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Sample records for biocontrol harlequin ladybird

  1. Predicting the potential geographical distribution of the harlequin ladybird, Harmonia axyridis, using the CLIMEX model - BioControl

    NARCIS (Netherlands)

    Poutsma, J.; Loomans, A.; Aukema, B.; Heijerman, Th.

    2008-01-01

    Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) is a ladybird beetle native to temperate and subtropical parts of Asia. Since 1916 populations of this species have been introduced throughout the world, either deliberately, or by accident through international transport. Harmonia axyridi

  2. The harlequin ladybird, Harmonia axyridis

    DEFF Research Database (Denmark)

    Roy, Helen E.; Brown, Peter M.J.; Adriaens, Tim;

    2016-01-01

    The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is native to Asia but has been intentionally introduced to many countries as a biological control agent of pest insects. In numerous countries, however, it has been introduced unintentionally. The dramatic spread of H...

  3. Entomopathogenic fungi recorded from the harlequin ladybird, Harmonia axyridis

    DEFF Research Database (Denmark)

    Steenberg, Tove; Harding, Susanne

    2009-01-01

    Entomopathogenic fungi were recorded from field samples of the harlequin ladybird Harmonia axyridis, an invasive coccinellid that has recently arrived in Denmark. Larvae, pupae and adults were found to be infected by Isaria farinosa, Beauveria bassiana and species of Lecanicillium...

  4. Comment on "Invasive harlequin ladybird carries biological weapons against native competitors".

    Science.gov (United States)

    de Jong, Peter W; van Lenteren, Joop C; Raak-van den Berg, C Lidwien

    2013-09-20

    We comment on the implications that Vilcinskas et al. (Reports, 17 May 2013, p. 862) attach to the finding that the exotic, invasive ladybird Harmonia axyridis carries microsporidia to which this species is insensitive but that is lethal to species that are native to the invaded areas. The authors suggest that these microsporidia might serve as "biological weapons" against the native competitors, but we cast doubt on the importance of this suggestion in the field.

  5. Natural flightless morphs of the ladybird beetle Adalia bipunctata improve biological control of aphids on single plants

    NARCIS (Netherlands)

    Lommen, S.T.E.; Middendorp, C.W.; Luijten, C.A.; Schelt, van J.; Brakefield, P.M.; Jong, de P.W.

    2008-01-01

    The challenge of using ladybird beetles for biological control of insect pests such as aphids is that the adult beetles tend to fly away from the host plants. Therefore, flightless ladybirds might improve biocontrol. There are several artificial ways to obtain flightless beetles, but it may be prefe

  6. First finding of the parasitic fungus Hesperomyces virescens (Laboulbeniales on native and invasive ladybirds (Coleoptera, Coccinellidae in South Africa

    Directory of Open Access Journals (Sweden)

    Haelewaters Danny

    2016-01-01

    Full Text Available Hesperomyces virescens is a fungal ectoparasite (Laboulbeniales that infects adult ladybirds. Research has recently focused on this parasite due to the discovery of its prevalence on the globally invasive harlequin ladybird Harmonia axyridis and for its potential use in studies of co-evolution and pathogen spread. We collected adults from ten species of ladybirds in the Western Cape Province, South Africa, and screened for the presence of H. virescens. Infections with H. virescens were found in the samples of two species, H. axyridis and the native Cheilomenes propinqua. This marks the first record of H. virescens on H. axyridis from the African continent and the first record on Cheilomenes worldwide.

  7. Persecutors, Victims and Rescuers in Harlequin Romances.

    Science.gov (United States)

    Hassencahl, Fran

    Based on a pattern of interaction, in which the interactants fulfill the roles of victim, persecutor, or rescuer, a study of ten Harlequin romantic novels was undertaken to determine what factors provided for the readers' identification with the Harlequin characters. It was found that Harlequin heroines manifested their status as victims by…

  8. Intraguild predation and successful invasion by introduced ladybird beetles.

    Science.gov (United States)

    Snyder, William E; Clevenger, Garrett M; Eigenbrode, Sanford D

    2004-08-01

    Introductions of two ladybird beetle (Coleoptera: Coccinellidae) species, Coccinella septempunctata and Harmonia axyridis, into North America for aphid biocontrol have been followed by declines in native species. We examined intraguild predation (IGP) between larvae of these two exotic species and larvae of the two most abundant native coccinellids in eastern Washington State, C. transversoguttata and Hippodamia convergens. In pairings between the two native species in laboratory microcosms containing pea ( Pisum sativum) plants, neither native had a clear advantage over the other in IGP. When the natives were paired with either Harmonia axyridis or C. septempunctata, the natives were more frequently the victims than perpetrators of IGP. In contrast, in pairings between the exotic species, neither had an IGP advantage, although overall rates of IGP between these two species were very high. Adding alternative prey (aphids) to microcosms did not alter the frequency and patterns of relative IGP among the coccinellid species. In observations of encounters between larvae, the introduced H. axyridis frequently survived multiple encounters with the native C. transversoguttata, whereas the native rarely survived a single encounter with H. axyridis. Our results suggest that larvae of the native species face increased IGP following invasion by C. septempunctata and H. axyridis, which may be contributing to the speed with which these exotic ladybird beetles displace the natives following invasion.

  9. Sudden Infant Death Syndrome with Harlequin Fetus

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    Selahattin Katar

    2007-01-01

    Full Text Available The harlequin fetus, a severe variant of ichthyosis, occurs rarely, and these babies die within the first few days of life. Early retinoid therapy may improve the disorder and help increase survival rates. The exact cause of the sudden infant death syndrome of the suckling is not known and the incidence approximately is 0.1-0.3 %. In general, these babies looked well and healthy at the time of the sleeping but were found dead in their bed in the morning. We report a harlequin fetus with sudden infant death syndrome.

  10. Potential for exploitative competition, not intraguild predation, between invasive harlequin ladybirds and flowerbugs in urban parks

    DEFF Research Database (Denmark)

    Howe, Andrew Gordon; Ravn, Hans Peter; Pipper, Christian Bressen

    2016-01-01

    -content analysis, we investigated the relative frequencies of IGP by H. axyridis on the predatory flowerbug Anthocoris nemoralis Fabricius (Heteroptera: Anthocoridae) and prey overlap for a shared prey, the lime aphid Eucallipterus tiliae L. (Hemiptera: Aphididae), in Tilia × europaea crowns in urban parks...

  11. Reproduction in Risky Environments: The Role of Invasive Egg Predators in Ladybird Laying Strategies.

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    Sarah C Paul

    Full Text Available Reproductive environments are variable and the resources available for reproduction are finite. If reliable cues about the environment exist, mothers can alter offspring phenotype in a way that increases both offspring and maternal fitness ('anticipatory maternal effects'-AMEs. Strategic use of AMEs is likely to be important in chemically defended species, where the risk of offspring predation may be modulated by maternal investment in offspring toxin level, albeit at some cost to mothers. Whether mothers adjust offspring toxin levels in response to variation in predation risk is, however, unknown, but is likely to be important when assessing the response of chemically defended species to the recent and pervasive changes in the global predator landscape, driven by the spread of invasive species. Using the chemically defended two-spot ladybird, Adalia bipunctata, we investigated reproductive investment, including egg toxin level, under conditions that varied in the degree of simulated offspring predation risk from larval harlequin ladybirds, Harmonia axyridis. H. axyridis is a highly voracious alien invasive species in the UK and a significant intraguild predator of A. bipunctata. Females laid fewer, larger egg clusters, under conditions of simulated predation risk (P+ than when predator cues were absent (P-, but there was no difference in toxin level between the two treatments. Among P- females, when mean cluster size increased there were concomitant increases in both the mass and toxin concentration of eggs, however when P+ females increased cluster size there was no corresponding increase in egg toxin level. We conclude that, in the face of offspring predation risk, females either withheld toxins or were physiologically constrained, leading to a trade-off between cluster size and egg toxin level. Our results provide the first demonstration that the risk of offspring predation by a novel invasive predator can influence maternal investment in

  12. Evolutionary Perspectives on Myrmecophily in Ladybirds

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    Amélie Vantaux

    2012-01-01

    Full Text Available Myrmecophiles are species that usually have developed specialized traits to cope with the aggressiveness of ants enabling them to live in their vicinity. Many coccinellid species are predators of Hemiptera; the latter is also often protected by ants. Therefore these ladybirds frequently interact with ants, and some species have become myrmecophilous. In this paper, we aim to provide an overview of the evolution of myrmecophilous traits in ladybirds. We then discuss the costs and benefits of myrmecophily and the dietary shift to myrmecophagy observed in a few species.

  13. Eating chemically defended prey: alkaloid metabolism in an invasive ladybird predator of other ladybirds (Coleoptera: Coccinellidae).

    Science.gov (United States)

    Sloggett, J J; Davis, A J

    2010-01-15

    By comparison with studies of herbivore physiological adaptation to plant allelochemicals, work on predator physiological adaptation to potentially toxic prey has been very limited. Such studies are important in understanding how evolution could shape predator diets. An interesting question is the specificity of predator adaptation to prey allelochemicals, given that many predators consume diverse prey with different chemical defences. The ladybird Harmonia axyridis, an invasive species in America, Europe and Africa, is considered a significant predatory threat to native invertebrates, particularly other aphid-eating ladybirds of which it is a strong intraguild predator. Although ladybirds possess species-specific alkaloid defences, H. axyridis exhibits high tolerance for allospecific ladybird prey alkaloids. Nonetheless, it performs poorly on species with novel alkaloids not commonly occurring within its natural range. We examined alkaloid fate in H. axyridis larvae after consumption of two other ladybird species, one containing an alkaloid historically occurring within the predator's native range (isopropyleine) and one containing a novel alkaloid that does not (adaline). Our results indicate that H. axyridis rapidly chemically modifies the alkaloid to which it has been historically exposed to render it less harmful: this probably occurs outside of the gut. The novel, more toxic alkaloid persists in the body unchanged for longer. Our results suggest metabolic alkaloid specialisation, in spite of the diversity of chemically defended prey that the predator consumes. Physiological adaptations appear to have made H. axyridis a successful predator of other ladybirds; however, limitations are imposed by its physiology when it eats prey with novel alkaloids.

  14. Congenital Cases of Concomitant Harlequin and Horner Syndromes.

    Science.gov (United States)

    Miquel, Juliette; Piyaraly, Saguiraly; Dupuy, Alain; Cochat, Pierre; Phan, Alice

    2017-03-01

    We report three pediatric cases of concomitant congenital Horner and Harlequin syndromes. This association suggests a lesion at the superior cervical ganglion or just inferior. Often, no underlying lesion is documented.

  15. Invasions by ladybugs, ladybirds, and other predatory Coleoptera

    OpenAIRE

    Evans, Edward W.; Soares, António O.; Yasuda, Hironori

    2011-01-01

    Copyright © International Organization for Biological Control (IOBC) 2011. Species of predatory Coleoptera have become abundant in new geographic regions recently, raising concerns for invaded ecosystems. We address this topic by focusing on invasive alien ladybird beetles (Coccinellidae; known also as ladybugs). Humans appear directly or indirectly responsible for all or most ladybird invasions. Factors hypothesized to have promoted ladybird invasions include genetic diversity (e.g., for ...

  16. Predation of Ladybird Beetles (Coleoptera: Coccinellidae by Amphibians

    Directory of Open Access Journals (Sweden)

    John J. Sloggett

    2012-07-01

    Full Text Available Studies of predation of ladybird beetles (Coccinellidae have focused on a limited number of predator taxa, such as birds and ants, while other potential predators have received limited attention. I here consider amphibians as predators of ladybirds. Published amphibian gut analyses show that ladybirds are quite often eaten by frogs and toads (Anura, with recorded frequencies reaching up to 15% of dietary items. Salamanders (Caudata eat ladybirds less frequently, probably as their habits less often bring them into contact with the beetles. Amphibians do not appear to be deleteriously affected by the potentially toxic alkaloids that ladybirds possess. Amphibians, especially frogs and toads, use primarily prey movement as a release cue to attack their food; it is thus likely that their ability to discriminate against ladybirds and other chemically defended prey is limited. Because of this poor discriminatory power, amphibians have apparently evolved non-specific resistance to prey defensive chemicals, including ladybird alkaloids. Although amphibian-related ladybird mortality is limited, in certain habitats it could outweigh mortality from more frequently studied predators, notably birds. The gut analyses from the herpetological literature used in this study, suggest that in studying predation of insects, entomologists should consider specialized literature on other animal groups.

  17. Idiopathic Harlequin Syndrome Manifesting during Exercise: A Case Report and Review of the Literature

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    Hussein Algahtani

    2017-01-01

    Full Text Available Harlequin syndrome is a rare autonomic disorder characterized by unilateral facial flushing and sweating with contralateral anhidrosis induced by exercise, heat, and emotion. It is usually idiopathic but could be the first manifestation of several serious underlying medical conditions. Medical or surgical treatments are not required for idiopathic Harlequin syndrome, but social and psychological factors may indicate sympathectomy or botulinum toxin injection. In this article, we report a case of idiopathic Harlequin syndrome and review the literature.

  18. Predator efficiency reconsidered for a ladybird-aphid system

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    Pavel eKindlmann

    2015-03-01

    Full Text Available Some experiments indicate that ladybirds can significantly suppress aphid abundance. For example, exclusion of predators by caging aphid-infested plants repeatedly results in higher aphid populations and faster aphid population growth rates. However, aphidophagous ladybirds have never proved effective in controlling aphid populations in the field, which is consistent with the theoretical prediction that long-lived predators cannot be effective in controlling a short-lived prey (the generation time ratio hypothesis, GTR. To resolve this paradox, field experiments, involving two species of ladybirds, Coccinella septempunctata bruckii and Harmonia axyridis were used to determine their efficiency in suppressing populations of the aphid, Aphis gossypii, on small shrubs of Hibiscus syriacus under natural conditions. Instead of by caging, the effect of each ladybird species on aphid population dynamics was determined by removing all the eggs of C. septempunctata from 8 shrubs, those of H. axyridis from a further 8 shrubs, all those of both species from an additional 12 shrubs and leaving the eggs on 6 control shrubs. These predators did not have a negative effect on the peak numbers of the aphids. Thus one should be cautious when interpreting the results of cage experiments, used to assess the efficiency of predators in reducing the abundance of their prey.

  19. Harlequin duck capture and EROD activity data from Prince William Sound, Alaska, 2011, 2013, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes capture information and ethoxyresorufin­O­deethylase (EROD) activity results for harlequin ducks sampled during March 2011, 2013, and 2014 in...

  20. Expecting the most unexpected – a harlequin baby! A case report and literature analysis

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    Sundaramoorthy M. Srinivasan

    2012-10-01

    Full Text Available Twenty eight years old primi gave birth to an amazing live baby by vaginal delivery – a Harlequin. The child was born with massive, diamond-shaped scales which limit the child’s movements. The term harlequin comes from the baby’s facial expression and diamond-shaped pattern of the scales like the 17th century entertainers, harlequins. As the skin cracks at places of movement the protective function of the skin is lost. Till now the prenatal diagnosis was based on biopsy of fetal skin carried out in an advanced stage of pregnancy. The most important indication of fetal cutaneous biopsy is the diagnosis of genodermatosis and hereditary diseases including Harlequin ichthyosis. It is predictable that for Harlequin Ichthyosis the prenatal test based on DNA will replace the fetal biopsy made before tenth week of gestation by chorionic villus sampling, or even before, with non-invasive analysis of the DNA of fetal cells in maternal circulation. Advances in neonatal intensive care along with scaling being made easier by the use of systemic retinoids has led to improved survival and the use of the name “Harlequin baby” to “Harlequin fetus”, “World’s Largest Baby” or “World’s Smallest Baby”. The mortality rate for harlequin ichthyosis is high. With neonatal intensive care and the advent of retinoid therapy, some babies have survived the newborn period. They are still at risk of dying from systemic infection. It’s the world’s most unconquired medical challenge.

  1. A Rare Case of Hemifacial Flushing and Hyperhydrosis: Harlequin Syndrome

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    Selma Korkmaz

    2015-09-01

    Full Text Available Harlequin syndrome (HS is a rare disorder, characterized by hemifacial flushing and sweating. This condition is induced by exercise, heat and emotional factors. There are sudomotor and vasomotor deficits in the cervical sympathetic chain. The syndrome is usually benign and does not require treatment. Most of the HS cases are primary in nature and no underlying cause can be identified, but may be associated with a secondary cause such as organic lesion. Here, we diagnosed idiopathic HS in a 20-year-old female who presented with increased facial flushing and sweating in the left half of the face which were mainly induced by exercise and emotional factors and it was reported together with literature.

  2. Differences in the predatory behaviour of male and female ladybird beetles (Coccinellidae

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    Jan Šipoš

    2012-09-01

    Full Text Available We investigated the response of males and females of ladybirds to different densities of aphids. This was studied using Coccinella septempunctata as the predator and Rhopalosiphum padi as the prey. Interactions between this ladybird and prey were observed on barley (Hordeum vulgare. We established aphid colonies on barley at three different densities, 16, 32 and 84 aphids per pot. Adult ladybirds placed in these colonies were then observed for 10 minutes or until they flew away. We hypothesized that females should consume more aphids than males per unit time. The results of this experiment revealed that the risk of aphid mortality per plant depended on the sex of the ladybird beetle. Female ladybirds consumed significantly more aphids than males per unit time. In addition the turning rate and time spent resting differed between the sexes.

  3. Attraction of harlequin bug (Hemiptera: Pentatomidae) to male-produced pheromone and host plants in the field

    Science.gov (United States)

    The harlequin bug is a serious stink bug pest of cruciferous vegetables. New tools are needed for vegetable growers to manage this pest with reduced or no pesticide inputs. We investigated attractants for harlequin bugs as part of a larger project to develop new traps or trap crops to manage this ...

  4. Host plant preference of harlequin bug (Hemiptera: Pentatomidae), and evaluation of a trap cropping strategy for its control in collard.

    Science.gov (United States)

    Wallingford, Anna K; Kuhar, Thomas P; Pfeiffer, Douglas G; Tholl, Dorothea B; Freeman, Joshua H; Doughty, Hélène B; Schultz, Peter B

    2013-02-01

    Harlequin bug, Murgantia histrionica (Hahn) (Hemiptera: Pentatomidae), is a piercing-sucking pest of cole crops, causing cosmetic damage in low populations, while heavy pest pressure can kill plants or entire fields. Field studies were conducted to evaluate a trap crop for control of harlequin bug in collard. Field-cage choice tests found that potential trap crop plant species, mustard (Brassica juncea 'Southern Giant Curled'), rapeseed (B. napus 'Athena'), rapini (B. rapa), and arugula (Eruca satica) attracted more harlequin bugs than collard (B. oleracea 'Champion') and a nonbrassica control, bean (Phaseolus vulgaris'Bronco'). Mustard was the most consistently selected by harlequin bug over collard in choice tests, and was found to be an effective trap crop for reducing feeding injury on collard at two experimental sites. Augmentation of the mustard trap crop with a systemic, neonicotinoid insecticide provided no added control of harlequin bug for the 10 wk duration in the spring season.

  5. Biocontrol of ticks.

    Science.gov (United States)

    Samish, M

    2000-01-01

    The increasing resistance of arthropodes to pesticides, their high price, and the growing public demand for safer food and a cleaner environment are obliging animal growers to minimize the use of pesticides by introducing alternative means for tick control. The development of a biological tick control method has been neglected as compared to the control of plant pests or dipterous insects harmful to men and animals. There are abundant observations, but only a few studies have as yet been conducted on pathogens, parasitoides, and predators of ticks. A first attempt at tick biocontrol was made with the introduction of tick-parasitic wasps from France to the USA and Russia. During the past decade, interest in developing antitick biocontrol agents such as birds (Brazil, Kenya, and Zimbabwe), parasitoides (Kenya and USA), entomopathogenic nematodes (Egypt, Israel, Guadeloupe, and USA), entomopathogenic fungi (Brazil, Cuba, Israel, Kenya, and USA), and bacteria (Brazil) has gained momentum. The reintroduction of oxpecker birds in some areas of Zimbabwe remains up to now the only known successful attempt at tick biocontrol.

  6. Slow and fast development in ladybirds: occurrence, effects and significance

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    G. Mishra

    2012-05-01

    Full Text Available Developmental and growth rates are known to vary in response to genetic, developmental, physiological and environmental factors. However, developmental variations that exist within a cohort under any constant rearing condition are not so well investigated. A few such prominent polymorphisms have been studied, but not the subtle ones. The current study investigates the presence of such varying rates of development, slow and fast, in a cohort reared under constant conditions in two ladybirds, Cheilomenes sexmaculata and Propylea dissecta. Our results reveal slow and fast developers in the cohorts of each species and the ratio of slow and fast developers was similar. Slow developers showed a female biased sex ratio. The two developmental variants differed significantly in juvenile duration only in the first instar and the pupal stage, though variations in developmental time were observed in all stages. Fecundity was higher in slow developers, but developmental rates did not affect egg viability. The similar ratio in both ladybirds indicates it to be a result of either presence of a constant ratio across species or an effect of the similar rearing environment.

  7. Harlequin ichthyosis in an infant born to a father with eczema.

    Science.gov (United States)

    Fatima, Saba; Rafiq, Ali; Majid, Zain

    2015-04-01

    Harlequin ichthyosis is characterized by thickening of the layer of the skin which contains keratin. Eczema is a chronic relapsing skin disorder which is also associated with disrupted epidermal barrier. We report the case of a 6-hour-old male patient who was brought to the neonatal intensive care unit of our hospital with crusting skin lesions all over the body, presence of a severe ectropion and deranged electrolytes. A diagnosis of harlequin ichthyosis was made, and the neonate was managed accordingly. However, the infant eventually expired on the seventh day of life. The infant's father was a patient of eczema with a chronic relapsing course and was on oral steroid therapy. As per our knowledge, this is the first reported case of an infant with harlequin ichthyosis born to a father suffering from eczema. The similarities in the pathogenesis of the two diseases and the genetic mutation of filaggrin might suggest an association between the two conditions. Harlequin ichthyosis can hence be looked out for in infants born of parents with eczema.

  8. PCB exposure in sea otters and harlequin ducks in relation to history of contamination by the Exxon Valdez oil spill

    Science.gov (United States)

    Ricca, Mark A.; Miles, A. Keith; Ballachey, Brenda E.; Bodkin, James L.; Esler, Daniel; Trust, Kimberly A.

    2010-01-01

    Exposure to contaminants other than petroleum hydrocarbons could confound interpretation of Exxon Valdez oil spill effects on biota at Prince William Sound, Alaska. Hence, we investigated polychlorinated biphenyls (PCBs) in blood of sea otters and harlequin ducks sampled during 1998. PCB concentrations characterized by lower chlorinated congeners were highest in sea otters from the unoiled area, whereas concentrations were similar among harlequin ducks from the oiled and unoiled area. Blood enzymes often elevated by xenobiotics were not related to PCB concentrations in sea otters. Only sea otters from the unoiled area had estimated risk from PCBs, and PCB composition or concentrations did not correspond to reported lower measures of population performance in sea otters or harlequin ducks from the oiled area. PCBs probably did not influence limited sea otter or harlequin duck recovery in the oiled area a decade after the spill.

  9. Evaluation of a Portable Automated Serum Chemistry Analyzer for Field Assessment of Harlequin Ducks, Histrionicus histrionicus

    OpenAIRE

    Michael K. Stoskopf; Daniel M. Mulcahy; Daniel Esler

    2010-01-01

    A portable analytical chemistry analyzer was used to make field assessments of wild harlequin ducks (Histrionicus histrionicus) inassociation with telemetry studies of winter survival in Prince William Sound, Alaska. We compared serum chemistry resultsobtained on-site with results from a traditional laboratory. Particular attention was paid to serum glucose and potassiumconcentrations as potential indicators of high-risk surgical candidates based on evaluation of the field data. Themedian dif...

  10. Mouse studies to shape clinical trials for mitochondrial diseases: high fat diet in Harlequin mice.

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    Manuel Schiff

    Full Text Available BACKGROUND: Therapeutic options in human mitochondrial oxidative phosphorylation (OXPHOS diseases have been poorly evaluated mostly because of the scarcity of cohorts and the inter-individual variability of disease progression. Thus, while a high fat diet (HFD is often recommended, data regarding efficacy are limited. Our objectives were 1 to determine our ability to evaluate therapeutic options in the Harlequin OXPHOS complex I (CI-deficient mice, in the context of a mitochondrial disease with human hallmarks and 2 to assess the effects of a HFD. METHODS AND FINDINGS: Before launching long and expensive animal studies, we showed that palmitate afforded long-term death-protection in 3 CI-mutant human fibroblasts cell lines. We next demonstrated that using the Harlequin mouse, it was possible to draw solid conclusions on the efficacy of a 5-month-HFD on neurodegenerative symptoms. Moreover, we could identify a group of highly responsive animals, echoing the high variability of the disease progression in Harlequin mice. CONCLUSIONS: These results suggest that a reduced number of patients with identical genetic disease should be sufficient to reach firm conclusions as far as the potential existence of responders and non responders is recognized. They also positively prefigure HFD-trials in OXPHOS-deficient patients.

  11. Characteristics and drivers of high-altitude ladybird flight: insights from vertical-looking entomological radar.

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    Daniel L Jeffries

    Full Text Available Understanding the characteristics and drivers of dispersal is crucial for predicting population dynamics, particularly in range-shifting species. Studying long-distance dispersal in insects is challenging, but recent advances in entomological radar offer unique insights. We analysed 10 years of radar data collected at Rothamsted Research, U.K., to investigate characteristics (altitude, speed, seasonal and annual trends and drivers (aphid abundance, air temperature, wind speed and rainfall of high-altitude flight of the two most abundant U.K. ladybird species (native Coccinella septempunctata and invasive Harmonia axyridis. These species cannot be distinguished in the radar data since their reflectivity signals overlap, and they were therefore analysed together. However, their signals do not overlap with other, abundant insects so we are confident they constitute the overwhelming majority of the analysed data. The target species were detected up to ∼1100 m above ground level, where displacement speeds of up to ∼60 km/h were recorded, however most ladybirds were found between ∼150 and 500 m, and had a mean displacement of 30 km/h. Average flight time was estimated, using tethered flight experiments, to be 36.5 minutes, but flights of up to two hours were observed. Ladybirds are therefore potentially able to travel 18 km in a "typical" high-altitude flight, but up to 120 km if flying at higher altitudes, indicating a high capacity for long-distance dispersal. There were strong seasonal trends in ladybird abundance, with peaks corresponding to the highest temperatures of mid-summer, and warm air temperature was the key driver of ladybird flight. Climatic warming may therefore increase the potential for long-distance dispersal in these species. Low aphid abundance was a second significant factor, highlighting the important role of aphid population dynamics in ladybird dispersal. This research illustrates the utility of radar for studying high

  12. Use of ryegrass strips to enhance biological control of aphids by ladybirds in wheat fields

    Institute of Scientific and Technical Information of China (English)

    Zhao-Ke Dong; Feng-Juan Gao; Run-Zhi Zhang

    2012-01-01

    Non-crop habitats may play a vital role in conservation biological control.This study tested the effect of ryegrass (Lolium muitiflorum L.) strips on aphid and ladybird populations in adjacent winter wheat fields.The field experiment was conducted in three ryegrass-margin wheat plots and three control plots in 2010 in North China.In spring,the same aphid species,Sitobion miscanthi (Takahashi),was found in both the ryegrass strips and wheat plots.The population density of ladybirds in the ryegrass strips (3.5±0.9/m2) was significantly higher than in the wheat plots (1.5±0.5/m2).We cut the ryegrass,forcing the ladybirds to migrate to the wheat fields.Three and eight days after cutting the ryegrass,the aphid numbers in the ryegrass-margin wheat plots decreased significantly:they were 19.9% and 53.6%,respectively,lower than in control plots.In the early period of ladybird population development,the percentage of larvae was greater in the ryegrass-margin wheat plots than in controls,and the peak number of pupae in the ryegrass-margin wheat plots occurred 5 days earlier than in the control plots.The results suggest that ryegrass strips may promote the development of ladybird populations.Cutting ryegrass can manipulate ladybirds to enhance biological aphid control in wheat fields.The efficiency of this management approach is discussed.

  13. Cessation of oil exposure in harlequin ducks after the Exxon Valdez oil spill: Cytochrome P4501A biomarker evidence.

    Science.gov (United States)

    Esler, Daniel; Ballachey, Brenda E; Bowen, Lizabeth; Miles, A Keith; Dickson, Rian D; Henderson, John D

    2016-10-20

    The authors quantified hepatic hydrocarbon-inducible cytochrome P4501A (CYP1A) expression, as ethoxyresorufin-O-deethylase (EROD) activity, in wintering harlequin ducks (Histrionicus histrionicus) captured in Prince William Sound, Alaska (USA), during 2011, 2013, and 2014 (22-25 yr following the 1989 Exxon Valdez oil spill). Average EROD activity was compared between birds from areas oiled by the spill and those from nearby unoiled areas. The present study replicated studies conducted from 1998 to 2009 demonstrating that harlequin ducks using areas oiled in 1989 had elevated EROD activity, indicative of oil exposure, up to 2 decades post spill. In the present study, it was found that average EROD activity during March 2011 was significantly higher in wintering harlequin ducks captured in oiled areas relative to unoiled areas, which the authors interpret to indicate that harlequin ducks continued to be exposed to residual Exxon Valdez oil up to 22 yr after the original spill. However, the 2011 results also indicated reductions in exposure relative to previous years. Average EROD activity in birds from oiled areas was approximately 2 times that in birds from unoiled areas in 2011, compared with observations from 2005 to 2009, in which EROD activity was 3 to 5 times higher in oiled areas. It was also found that average EROD activity during March 2013 and March 2014 was not elevated in wintering harlequin ducks from oiled areas. The authors interpret these findings to indicate that exposure of harlequin ducks to residual Exxon Valdez oil abated within 24 yr after the original spill. The present study finalizes a timeline of exposure, extending over 2 decades, for a bird species thought to be particularly vulnerable to oil contamination in marine environments. Environ Toxicol Chem 2016;9999:1-7. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

  14. Chronic hydrocarbon exposure of harlequin ducks in areas affected by the Selendang Ayu oil spill at Unalaska Island, Alaska

    Science.gov (United States)

    Flint, Paul L.; Schamber, J.L.; Trust, K.A.; Miles, A.K.; Henderson, J.D.; Wilson, B.W.

    2012-01-01

    We evaluated chronic exposure of harlequin ducks (Histrionicus histrionicus) to hydrocarbons associated with the 2004 M/V Selendang Ayu oil spill at Unalaska Island, Alaska. We measured levels of hepatic 7-ethoxyresorufin-O-deethylase activity (EROD) in liver biopsy samples as an indicator of hydrocarbon exposure in three oiled bays and one reference bay in 2005, 2006, and 2008. Median EROD activity in ducks from oiled bays was significantly higher than in the reference bay in seven of nine pairwise comparisons. These results indicated that harlequin ducks were exposed to lingering hydrocarbons more than three years after the spill.

  15. New record of predatory ladybird beetle (Coleoptera, Coccinellidae feeding on extrafloral nectaries

    Directory of Open Access Journals (Sweden)

    Lúcia M. Almeida

    2011-09-01

    Full Text Available New record of predatory ladybird beetle (Coleoptera, Coccinellidae feeding on extrafloral nectaries. Feeding by Exoplectra miniata (Germar on extrafloral nectaries of Inga edulis Mart. was observed in Nova Friburgo, Rio de Janeiro, Brazil. This is the first record of this behavior for Exoplectrini.

  16. The influence of age on reproductive performance of the predatory ladybird beetle, Propylea dissecta

    Directory of Open Access Journals (Sweden)

    Ahmad Pervez

    2004-07-01

    Full Text Available The influence of age on reproductive performance of an aphidophagous ladybird beetle, Propylea dissecta was examined using male and female beetles of varying ages (1-30 days after a single mating stimulus. All the intermediate (10 to 20 days old and old (30 days old age females mated with all intermediate and old age males, while only a fraction (0.29% of younger females, 1 to 5 days old, mated with males of similar or older age. The willingness to mate was male age dependent. It increased sigmoidally with increase in adult age. Adult males were more willing to mate with females irrespective of age. Mating duration was longest amongst older adults (30 day-old males and 20 day-old females. Male age did not contribute to shaping the fecundity of the female ladybird. Fecundity was female age dependent and it increased with age up to 20 days and thereafter decreased. 20 day-old females were most fecund producing 867 eggs after a single mating. Progeny production was male age dependent and eggs sired by 20-30 day-old males had significantly higher viability than those sired by younger males. Prolonged mating increased fecundity and egg viability. The results reveal that males of intermediate age were better mates. This information may improve our understanding of the effect of aging on reproduction in ladybirds and may help mass-multiplication of the ladybird beetles using adults of optimal age.

  17. Exploring and exploiting natural variation in the wings of a predatory ladybird beetle for biological control

    NARCIS (Netherlands)

    Lommen, Suzanne Theresia Esther

    2013-01-01

    The central theme of this PhD thesis is natural variation in the wing length of the predatory two-spot ladybird beetle, Adalia bipunctata. ‘Wingless’ individuals of this species occur occasionally. They possess truncated wing covers and flight wings and cannot fly, but the extent of the reduction is

  18. Bacteriophage biocontrol of foodborne pathogens.

    Science.gov (United States)

    Kazi, Mustafa; Annapure, Uday S

    2016-03-01

    Bacteriophages are viruses that only infect bacterial cells. Phages are categorized based on the type of their life cycle, the lytic cycle cause lysis of the bacterium with the release of multiple phage particles where as in lysogenic phase the phage DNA is incorporated into the bacterial genome. Lysogeny does not result in lysis of the host. Lytic phages have several potential applications in the food industry as biocontrol agents, biopreservatives and as tools for detecting pathogens. They have also been proposed as alternatives to antibiotics in animal health. Two unique features of phage relevant for food safety are that they are harmless to mammalian cells and high host specificity, keeping the natural microbiota undisturbed. However, the recent approval of bacteriophages as food additives has opened the discussion about 'edible viruses'. This article reviews in detail the application of phages for the control of foodborne pathogens in a process known as "biocontrol".

  19. Harlequin Syndrome in a Case of Toxic Goitre: A Rare Association

    Directory of Open Access Journals (Sweden)

    P. V. Pradeep

    2011-01-01

    Full Text Available Harlequin syndrome (HS is known to be associated with conditions like brain stem infarcts and superior mediastinal neurinoma. However, it has not been reported in association with autoimmune hyperthyroidism. We report a case of exacerbation of unilateral sweating in a patient with HS following the onset of toxic goitre. Previous reports have suggested that a tortuous inferior thyroid artery can produce neurovascular compression of the sympathetic chain which was not observed in our patient. Autoimmune aetiology for HS needs to be explored. Increased sweating in hyperthyroid patients needs to be assessed properly so as to prognosticate appropriately.

  20. Snowdrop lectin (GNA) has no acute toxic effects on a beneficial insect predator, the 2-spot ladybird (Adalia bipunctata L.).

    Science.gov (United States)

    Down, R E.; Ford, L; Woodhouse, S D.; Raemaekers, R J.M.; Leitch, B; Gatehouse, J A.; Gatehouse, A M.R.

    2000-04-01

    Two-spot ladybird (Adalia bipunctata L.) larvae were fed on aphids (Myzus persicae (Sulz.)) which had been loaded with snowdrop lectin (Galanthus nivalis agglutinin; GNA) by feeding on artificial diet containing the protein. Treatment with GNA significantly decreased the growth of aphids. No acute toxicity of GNA-containing aphids towards the ladybird larvae was observed, although there were small effects on development. When fed a fixed number of aphids, larvae exposed to GNA spent longer in the 4th instar, taking 6 extra days to reach pupation; however, retardation of development was not observed in ladybird larvae fed equal weights of aphids. Ladybird larvae fed GNA-containing aphids were found to be 8-15% smaller than controls, but ate a significantly greater number of aphids (approx. 40% to pupation). GNA was shown to be present on the microvilli of the midgut brush border membrane and within gut epithelial cells in ladybird larvae fed on GNA-dosed aphids, although disruption of the brush border was not observed. It is hypothesised that GNA does not have significant direct toxic or adverse effects on developing ladybird larvae, but that the effects observed may be due to the fact that the aphids fed on GNA are compromised and are thus a suboptimal food.

  1. Survival of captive and free-ranging Harlequin Ducks (Histrionicus histrionicus) following surgical liver biopsy

    Science.gov (United States)

    Mulcahy, Daniel M.; Esler, Daniel N.

    2010-01-01

    We measured intra- and postoperative mortality rates of captive and free-ranging Harlequin Ducks (Histrionicus histrionicus) undergoing surgical liver biopsy sampling for determination of the induction of cytochrome P4501A, a biomarker of oil exposure. Liver biopsies were taken from and radio transmitters were implanted into 157 free-ranging Harlequin Ducks over three winters (55 in 2000, 55 in 2001, and 47 in 2002). No birds died during surgery, but seven (4.5%) died during recovery from anesthesia (three in 2001 and four in 2002). None of the deaths could be attributed directly to the liver biopsy. Four of the 150 (2.7%) birds that were released died in the 2 wk period after surgery. All post-release deaths occurred in 2001; no birds died after release in 2000 or 2002. No mortalities of 36 captive birds occurred during surgery or recovery or in the 2 wk period following surgery. Hemorrhage was a minor problem with one captive bird. Surgical liver biopsies appear to be a safe procedure, but anesthetic complications may occur with overwintering ducks.

  2. Fast–slow continuum in the life history parameters of ladybirds revisited

    Directory of Open Access Journals (Sweden)

    A. F. G. Dixon

    2011-12-01

    Full Text Available A previous study of the rate of development of larvae of aphidophagous and coccidophagous ladybirds indicated that they both had the same lower developmental threshold (Ldt but that the coccidophagous species developed more slowly than the aphidophagous species. The current analysis of the rates of development of the eggs of 48 species belonging to 8 tribes, which were kept at a range of different temperatures, indicates that ladybirds do not all have the same Ldt, but that the of eggs of aphidophagous Coccinellini develop faster than those of coccidophagous Chilocorini and more importantly those of the aphidophagous genus Scymnus and the coccidophagous Nephus, both belonging to the same robust tribe, the Scymnini, also differ, with those of the latter genus developing more slowly. Possible reasons for this are discussed.

  3. Two strains of male-killing Wolbachia in a ladybird, Coccinella undecimpunctata, from a hot climate.

    Directory of Open Access Journals (Sweden)

    Sherif Elnagdy

    Full Text Available Ladybirds are a hot-spot for the invasion of male-killing bacteria. These maternally inherited endosymbionts cause the death of male host embryos, to the benefit of female sibling hosts and the bacteria that they contain. Previous studies have shown that high temperatures can eradicate male-killers from ladybirds, leaving the host free from infection. Here we report the discovery of two maternally inherited sex ratio distorters in populations of a coccinellid, Coccinella undecimpunctata, from a hot lowland region of the Middle East. DNA sequence analysis indicates that the male killing is the result of infection by Wolbachia, that the trait is tetracycline sensitive, and that two distinct strains of Wolbachia co-occur within one beetle population. We discuss the implications of these findings for theories of male-killing and suggest avenues for future field-work on this system.

  4. COMPARATIVE DEMOGRAPHICS OF A GENERALIST PREDATORY LADYBIRD ON FIVE APHID PREY: A LABORATORY STUDY

    Institute of Scientific and Technical Information of China (English)

    Omkar; AhmadPervez

    2004-01-01

    Prey driven demographic parameters of an aphidophagous ladybird, Propylea dissecta (Mulsant) were studied in attempt to answer how ladybird overcomes the problem of seasonally fluctuating food base. The ladybird reared for five generations in laboratory derived differential nutrition from five food sources (i.e. aphid species, Rhopalosiphum maidis (Fitch), Aphis craccivora Koch, Aphis gossypii Glover, Uroleucon compositae (Theobald) and Lipaphis erysimi (Kalt.)). The order of relative prey suitability was A. gossypii, A. craccivora, R. maidis, U. compositae and L.erysimi. Neonates suffered maximum mortality followed by eggs. Estimates of net reproductive rate,intrinsic rate of increase and finite rate of increase were highest (407.18, 0.2274 day-1, 1.2553 day-1) on A. gossypii and lowest (176.02, 0.1533 day-1, 1.1657 day-1) on L. erysimi. Generation time was shortest (26.43 days) on A. gossypii and longest (33.73 days) on L. erysimi. The present study thus,provides an explanation to the high incidence of P. dissecta on A. gossypii, as it experienced high intrinsic rate of increase and optimal values for related demographic parameters.

  5. Atomic force microscopy study of nano-physiological response of ladybird beetles to photostimuli.

    Directory of Open Access Journals (Sweden)

    Natalia V Guz

    Full Text Available BACKGROUND: Insects are of interest not only as the most numerous and diverse group of animals but also as highly efficient bio-machines varying greatly in size. They are the main human competitors for crop, can transmit various diseases, etc. However, little study of insects with modern nanotechnology tools has been done. METHODOLOGY/PRINCIPAL FINDINGS: Here we applied an atomic force microscopy (AFM method to study stimulation of ladybird beetles with light. This method allows for measuring of the internal physiological responses of insects by recording surface oscillations in different parts of the insect at sub-nanometer amplitude level and sub-millisecond time. Specifically, we studied the sensitivity of ladybird beetles to light of different wavelengths. We demonstrated previously unknown blindness of ladybird beetles to emerald color (∼500nm light, while being able to see UV-blue and green light. Furthermore, we showed how one could study the speed of the beetle adaptation to repetitive flashing light and its relaxation back to the initial stage. CONCLUSIONS: The results show the potential of the method in studying insects. We see this research as a part of what might be a new emerging area of "nanophysiology" of insects.

  6. Effect of age on reproductive attributes of an aphidophagous ladybird, Cheilomenes sexmaculata

    Institute of Scientific and Technical Information of China (English)

    OMKAR, SATYENDRA K. SINGH; KALPANA SINGH

    2006-01-01

    The effect of both male and female age was investigated on certain reproductive attributes, viz. mating incidence, mating duration, fecundity, percent egg viability, ratio of reproductive and non-reproductive periods and reproductive rate, of an aphidophagous ladybird, Cheilomenes sexmaculata (Fabricius). Females started mating at the age of 8 hours post-emergence (PE) and males at the age of 2 days PE. Mating in the laboratory was a maledominated phenomenon. The mating duration and reproductive rate of 10-day-old females when mated with males of varying ages increased up to the male age of 60 days, and thereafter decreased, whereas, fecundity, egg viability and ratio of reproductive and non-reproductive periods increased up to the male age of 50 days, and thereafter declined. However, when females of varying ages were mated with 10-day-old males, fecundity and reproductive rate increased up to 40 days of female age, respectively, then decreased. The ratio of reproductive and non-reproductive periods increased with increasing age of females. Mating age for optimal reproductive output was 10-50-day-old males and NE to 40-day-old females.Reproductive cessation in males was recorded after 50 days PE, whereas in females at the age of 40 days PE. Higher mating durations lead to elevated reproductive rates. Delay in the reproductive phase was positively correlated with longevity. The results of this study may aid mass multiplication of this ladybird by identifying and promoting usage of adults of optimal age. Our results also enhance our understanding of the effect of age on reproductive attributes in ladybirds.

  7. Does a change from whole to powdered food (Artemia franciscana eggs) increase oviposition in the ladybird Coleomegilla maculata

    Science.gov (United States)

    The limited availability of alternative foods to replace natural prey hinders cost-effective mass production of ladybird beetles for augmentative biological control. We compared the effects of powdered versus whole Artemia franciscana (brine shrimp) eggs with or without a dietary supplement on devel...

  8. Effects of bioflavonoids on oviposition behavior in the pink-spotted ladybird beetle Coleomegilla maculata (Coleoptera: Coccinellidae)

    Science.gov (United States)

    One goal of our current research is to mass produce ladybird beetles for biological control of plant pests in greenhouses and other protective structures. Cost-effective mass production involves the use of alternative prey/foods or artificial diets (rather than natural prey, e.g., aphids). One chall...

  9. Biotransfer of Cd along a soil-plant- mealybug-ladybird food chain: A comparison with host plants.

    Science.gov (United States)

    Wang, Xingmin; Zhang, Can; Qiu, Baoli; Ashraf, Umair; Azad, Rashid; Wu, Jianhui; Ali, Shaukat

    2017-02-01

    Agro-ecosystem contamination by the heavy metals present in different agricultural products is a serious challenge faced by the living organisms. This study explains the cadmium (Cd) transfer from soils contaminated with different cadmium concentrations through a plant (eggplant and tomato) - mealybug (Dysmicoccus neobrevipes) - predator (Cryptolaemus-montrouzieri) food chain. The soils were amended with Cd at the rates of 0, 12.5, 25 and 50 mg/kg (w/w). Our findings showed that considerably higher Cd transfer through tomato plant. Cadmium was biomagnified during soil-root transfer while bio-minimization of Cd was observed for shoot-mealybug - ladybird transfer. Our results further showed sequestration of Cd during the metamorphosis of ladybird beetle whilst transfer of Cd through soil-plant-mealybug-ladybird multi-trophic food chain increased in a dose dependent manner. Our results emphasize the need of further studies to elaborate possible mechanisms of Cd bio-minimization by plants, mealybugs and ladybirds observed during this study.

  10. Assessment of patch quality by aphidophagous ladybirds: laboratory study on the minimum density of aphids required for oviposition

    Directory of Open Access Journals (Sweden)

    B. C. Das

    2011-12-01

    Full Text Available Many studies indicate that there is a density of aphids below which ladybirds are unlikely to lay eggs. This is adaptive as theory indicates that a certain minimum population density of aphids is required if hatchling larvae are to survive. The responses of gravid females of the two spot ladybird, Adalia bipunctata (L. (Coleoptera: Coccinellidae, recorded over a period of an hour, to colonies of 5 and 50 pea aphids on bean plants and similar plants each previously infested with the same number of aphids for 48 hours were determined. Proportionally more of the ladybirds on plants with 50 aphids or that were previously infested with the same number of aphids for 48 hours laid eggs and larger clusters of eggs, and were less active than those on plants that were infested with or had previously been infested with five aphids. That is, gravid females showed similar oviposition and activity responses to aphid abundance and different levels of honeydew contamination. This indicates that honeydew contamination may be an important cue used by ladybirds when locating and assessing the abundance of prey in aphid colonies.

  11. Survival, development and life tables of two congeneric ladybirds in aphidophagous guilds

    Institute of Scientific and Technical Information of China (English)

    AVANISH K. GUPTA; SHEFALI SRIVASTAVA; GEETANJALI MISHRA; KALPANA SINGH; OMKAR

    2006-01-01

    Two congeneric aphidophagous ladybirds, Coccinella septempunctata and Coccinella transversalis, were reared on three aphid species, Lipaphis erysimi, Myzus persicae and Aphis nerii, to estimate the effect of prey quality and intra- and interspecific interactions on their survival and development of life stages. Mortality of first instar ladybirds of both species was highest feeding on A. Nerii. Preimaginal mortality was lowest when feeding on L. Erysimi (C. Septempunctata, 1.6% and C. Transversalis, 3.2%), and highest when feeding on A. Nerii ( C. Septempunctata, 6.2% and C. Transversalis, 8.2%).Comparatively higher weight and larger size of C. Septempunctata along with the lower levels of mortality recorded suggested that it is more likely to have acted as an intraguild predator than C. Transversalis. High recorded mortality of C. Transversalis is attributed to probable intraguild predation on account of its smaller size. The major sources of mortality were probably cannibalism, intraguild predation and other unknown factors. Lower prey quality increased the incidence of cannibalism and intraguild predation, especially in C. Transversalis. The investigation suggests an intrinsic competitive advantage forC. Septempunctata over C. Transversalis in guilds of three aphid species.

  12. Research on predatory function reaction of three species ladybirds to wildMyzus persicae andHyalopterus arundimis%3种瓢虫对野生型桃蚜和桃粉蚜的捕食功能反应

    Institute of Scientific and Technical Information of China (English)

    任向辉; 杨萌; 李鹏; 陈燕飞; 汪治鹏; 刘婉婉; 白钰; 刘迎春; 陈丹丹

    2015-01-01

    The indoor predatory function reactions of the main natural enemies includingCoccinella septempunctata, Propylea japonica andLeis axyridis to the wildMyzus persicae andHyalopterus arundimis were studied in this paper. The results showed that the type of functional responses was Holling’s type II with the temperature of 25℃. By using disc equations regression with improved simplex method, the attack coefficients of three species ladybirds toMyzus persicae were 1.53953, 1.64510 and 1.28469 respectively, but the values toHyalopterus arundimis were 1.33421, 1.18244 and 1.12258 respectively. Furthermore, the handling time values of three species ladybirds toMyzus persicae were 0.02392, 0.02747 and 0.00908 respectively, and the values toHyalopterus arundimis were 0.01381, 0.01476 and 0.01056 respectively. In conclusion these parameters would provide the guidance for the biocontrol of these aphides.%研究桃树蚜虫的主要捕食性天敌七星瓢虫、龟纹瓢虫和异色瓢虫对野生型桃蚜和桃粉蚜个体的室内捕食功能反应,发现25℃条件下3种瓢虫的成虫的捕食功能反应类型为Hol ingI 型。圆盘方程加速单纯形法回归分析表明,七星瓢虫、龟纹瓢虫和异色瓢虫对桃蚜无翅成蚜的攻击系数依次为1.53953、1.64510、1.28469,而对桃粉蚜无翅成蚜的攻击系数依次为1.33421、1.18244、1.12258;此外,七星瓢虫、龟纹瓢虫和异色瓢虫对桃蚜无翅成蚜的处理时间依次为0.02392、0.02747、0.00908,而对桃粉蚜无翅成蚜的处理时间依次为0.01381、0.01476、0.01056。这些参数为两种蚜虫的生物防治提供了理论指导。

  13. Commercialization of postharvest biocontrol: barriers and opportunities

    Science.gov (United States)

    The past twenty years has seen the field of postharvest biocontrol evolve from an unknown entity with one or two novel reports in the literature to a sophisticated science with strong research programs worldwide, hundreds of publications, patented technologies, and now several commercial products. ...

  14. Species sorting and patch dynamics in harlequin metacommunities affect the relative importance of environment and space.

    Science.gov (United States)

    Leibold, Mathew A; Loeuille, Nicolas

    2015-12-01

    Metacommunity theory indicates that variation in local community structure can be partitioned into components including those related to local environmental conditions vs. spatial effects and that these can be quantified using statistical methods based on variation partitioning. It has been hypothesized that joint associations of community composition with environment and space could be due to patch dynamics involving colonization-extinction processes in environmentally heterogeneous landscapes but this has yet to be theoretically shown. We develop a two-patch, type-two, species competition model in such a "harlequin" landscape (where different patches have different environments) to evaluate how composition is related to environmental and spatial effects as a function of background extinction rate. Using spatially implicit analytical models, we find that the environmental association of community composition declines with extinction rate as expected. Using spatially explicit simulation models, we further find that there is an increase in the spatial structure with extinction due to spatial patterning into clusters that are not related to environmental conditions but that this increase is limited. Natural metacommunities often show both environment and spatial determination even under conditions of relatively high isolation and these could be more easily explained by our model than alternative metacommunity models.

  15. Mutations in ABCA12 Underlie the Severe Congenital Skin Disease Harlequin Ichthyosis

    Science.gov (United States)

    Kelsell, David P.; Norgett, Elizabeth E.; Unsworth, Harriet; Teh, Muy-Teck; Cullup, Thomas; Mein, Charles A.; Dopping-Hepenstal, Patricia J.; Dale, Beverly A.; Tadini, Gianluca; Fleckman, Philip; Stephens, Karen G.; Sybert, Virginia P.; Mallory, Susan B.; North, Bernard V.; Witt, David R.; Sprecher, Eli; E. M. Taylor, Aileen; Ilchyshyn, Andrew; Kennedy, Cameron T.; Goodyear, Helen; Moss, Celia; Paige, David; Harper, John I.; Young, Bryan D.; Leigh, Irene M.; Eady, Robin A. J.; O’Toole, Edel A.

    2005-01-01

    Harlequin ichthyosis (HI) is the most severe and frequently lethal form of recessive congenital ichthyosis. Although defects in lipid transport, protein phosphatase activity, and differentiation have been described, the genetic basis underlying the clinical and cellular phenotypes of HI has yet to be determined. By use of single-nucleotide–polymorphism chip technology and homozygosity mapping, a common region of homozygosity was observed in five patients with HI in the chromosomal region 2q35. Sequencing of the ABCA12 gene, which maps within the minimal region defined by homozygosity mapping, revealed disease-associated mutations, including large intragenic deletions and frameshift deletions in 11 of the 12 screened individuals with HI. Since HI epidermis displays abnormal lamellar granule formation, ABCA12 may play a critical role in the formation of lamellar granules and the discharge of lipids into the intercellular spaces, which would explain the epidermal barrier defect seen in this disorder. This finding paves the way for early prenatal diagnosis. In addition, functional studies of ABCA12 will lead to a better understanding of epidermal differentiation and barrier formation. PMID:15756637

  16. A mouse model of harlequin ichthyosis delineates a key role for Abca12 in lipid homeostasis.

    Directory of Open Access Journals (Sweden)

    Ian Smyth

    Full Text Available Harlequin Ichthyosis (HI is a severe and often lethal hyperkeratotic skin disease caused by mutations in the ABCA12 transport protein. In keratinocytes, ABCA12 is thought to regulate the transfer of lipids into small intracellular trafficking vesicles known as lamellar bodies. However, the nature and scope of this regulation remains unclear. As part of an original recessive mouse ENU mutagenesis screen, we have identified and characterised an animal model of HI and showed that it displays many of the hallmarks of the disease including hyperkeratosis, loss of barrier function, and defects in lipid homeostasis. We have used this model to follow disease progression in utero and present evidence that loss of Abca12 function leads to premature differentiation of basal keratinocytes. A comprehensive analysis of lipid levels in mutant epidermis demonstrated profound defects in lipid homeostasis, illustrating for the first time the extent to which Abca12 plays a pivotal role in maintaining lipid balance in the skin. To further investigate the scope of Abca12's activity, we have utilised cells from the mutant mouse to ascribe direct transport functions to the protein and, in doing so, we demonstrate activities independent of its role in lamellar body function. These cells have severely impaired lipid efflux leading to intracellular accumulation of neutral lipids. Furthermore, we identify Abca12 as a mediator of Abca1-regulated cellular cholesterol efflux, a finding that may have significant implications for other diseases of lipid metabolism and homeostasis, including atherosclerosis.

  17. Evaluation of a Portable Automated Serum Chemistry Analyzer for Field Assessment of Harlequin Ducks, Histrionicus histrionicus.

    Science.gov (United States)

    Stoskopf, Michael K; Mulcahy, Daniel M; Esler, Daniel

    2010-01-01

    A portable analytical chemistry analyzer was used to make field assessments of wild harlequin ducks (Histrionicus histrionicus) in association with telemetry studies of winter survival in Prince William Sound, Alaska. We compared serum chemistry results obtained on-site with results from a traditional laboratory. Particular attention was paid to serum glucose and potassium concentrations as potential indicators of high-risk surgical candidates based on evaluation of the field data. The median differential for glucose values (N = 82) between methods was 0.6 mmol/L (quartiles 0.3 and 0.9 mmol/L) with the median value higher when assayed on site. Analysis of potassium on site returned a median of 2.7 mmol/L (N = 88; quartiles 2.4 and 3.0 mmol/L). Serum potassium values were too low for quantitation by the traditional laboratory. Changes in several serum chemistry values following a three-day storm during the study support the value of on site evaluation of serum potassium to identify presurgical patients with increased anesthetic risk.

  18. Harlequin, vampírur og mömmuklám. Um formúlu Twilight og Fifty Shades

    OpenAIRE

    Ragnheiður Jóhannsdóttir 1989

    2013-01-01

    Formúla Twilight seríunnar og Fifty Shades þríleiksins er tekin fyrir og skoðuð í samræmi við söguþráð Harlequin bækurnar, þar á eftir eru þær greindar út frá menningarlegu viðhorfi nútímans til fórnarlamba og gerenda, betur þekkt sem nauðgunarmenning.

  19. Intergenomic arms races: detection of a nuclear rescue gene of male-killing in a ladybird.

    Directory of Open Access Journals (Sweden)

    Tamsin M O Majerus

    Full Text Available Many species of arthropod are infected by deleterious inherited micro-organisms. Typically these micro-organisms are inherited maternally. Consequently, some, particularly bacteria of the genus Wolbachia, employ a variety of strategies that favour female over male hosts. These strategies include feminisation, induction of parthenogenesis and male-killing. These strategies result in female biased sex ratios in host populations, which lead to selection for host factors that promote male production. In addition, the intra-genomic conflict produced by the difference in transmission of these cytoplasmic endosymbionts and nuclear factors will impose a pressure favouring nuclear factors that suppress the effects of the symbiont. During investigations of the diversity of male-killing bacteria in ladybirds (Coccinellidae, unexpected patterns of vertical transmission of a newly discovered male-killing taxon were observed in the ladybird Cheilomenes sexmaculata. Initial analysis suggested that the expression of the bacterial male-killing trait varies according to the male(s a female has mated with. By swapping males between females, a male influence on the expression of the male-killing trait was confirmed. Experiments were then performed to determine the nature of the interaction. These studies showed that a single dominant allele, which rescues male progeny of infected females from the pathological effect of the male-killer, exists in this species. The gene shows typical Mendelian autosomal inheritance and is expressed irrespective of the parent from which it is inherited. Presence of the rescue gene in either parent does not significantly affect the inheritance of the symbiont. We conclude that C. sexmaculata is host to a male-killing gamma-proteobacterium. Further, this beetle is polymorphic for a nuclear gene, the dominant allele of which rescues infected males from the pathogenic effects of the male-killing agent. These findings represent the first

  20. Mating behavior of an aphidophagous ladybird beetle,Propylea dissecta (Mulsant)

    Institute of Scientific and Technical Information of China (English)

    OMKAR; AHMADPERVEZ

    2005-01-01

    The mating behavior of Propylea dissecta (Mulsant) was investigated in detail.Protandry was evident, as males mature earlier than females. Predicted age of sexual maturation of male and female ladybirds was 7.12 and 9.33 days, respectively. Males performed courtship in six steps, viz. approach, watch, examine, embrace, mount and attempt. Embrace is possibly an appeasement act, while examine serves to recognize mate.Chemical signals initiate male attraction toward females. Visual and tactile cues appear to secondarily help in mate recognition. Mating lasted longest (275.40 ± 12.23 min) when it occurred between unmated individuals. It was much shorter (176.60 ± 5.60 min) when prior mated individuals copulated. There was a significant decrease in mating durations when adults were subjected to five successive matings. Fecundity and percent egg viability increased significantly with increase in the number of matings.

  1. Olfactory cues from plants infected by powdery mildew guide foraging by a mycophagous ladybird beetle.

    Science.gov (United States)

    Tabata, Jun; De Moraes, Consuelo M; Mescher, Mark C

    2011-01-01

    Powdery mildews (Erysiphales) are economically important plant pathogens that attack many agricultural crops. Conventional management strategies involving fungicide application face challenges, including the evolution of resistance and concerns over impacts on non-target organisms, that call for investigation of more sustainable alternatives. Mycophagous ladybird beetles (Coleoptera: Coccinellidae) feed on powdery mildew and have considerable potential as biological control agents; however, the foraging ecology and behavior of these beetles is not well understood. Here we document the olfactory cues presented by squash plants (Cucurbita moschata) infected by powdery mildew (Podosphaera sp.) and the behavioral responses of twenty-spotted ladybird beetles (Psyllobora vigintimaculata) to these cues. Volatile analyses through gas chromatography revealed a number of volatile compounds characteristic of infected plants, including 3-octanol and its analogues 1-octen-3-ol and 3-octanone. These compounds are typical "moldy" odorants previously reported in volatiles collected from other fungi. In addition, infected plants exhibited elevated emissions of several compounds also observed in collections from healthy leaves, including linalool and benzyl alcohol, which are reported to have anti-fungal properties. In Y-tube choice assays, P. vigintimaculata beetles displayed a significant preference for the odors of infected plants compared to those of healthy plants. Moreover, beetles exhibited strong attraction to one individual compound, 1-octen-3-ol, which was the most abundant of the characteristic fungal compounds identified. These results enhance our understanding of the olfactory cues that guide foraging by mycophagous insects and may facilitate the development of integrated disease-management strategies informed by an understanding of underlying ecological mechanisms.

  2. Olfactory cues from plants infected by powdery mildew guide foraging by a mycophagous ladybird beetle.

    Directory of Open Access Journals (Sweden)

    Jun Tabata

    Full Text Available Powdery mildews (Erysiphales are economically important plant pathogens that attack many agricultural crops. Conventional management strategies involving fungicide application face challenges, including the evolution of resistance and concerns over impacts on non-target organisms, that call for investigation of more sustainable alternatives. Mycophagous ladybird beetles (Coleoptera: Coccinellidae feed on powdery mildew and have considerable potential as biological control agents; however, the foraging ecology and behavior of these beetles is not well understood. Here we document the olfactory cues presented by squash plants (Cucurbita moschata infected by powdery mildew (Podosphaera sp. and the behavioral responses of twenty-spotted ladybird beetles (Psyllobora vigintimaculata to these cues. Volatile analyses through gas chromatography revealed a number of volatile compounds characteristic of infected plants, including 3-octanol and its analogues 1-octen-3-ol and 3-octanone. These compounds are typical "moldy" odorants previously reported in volatiles collected from other fungi. In addition, infected plants exhibited elevated emissions of several compounds also observed in collections from healthy leaves, including linalool and benzyl alcohol, which are reported to have anti-fungal properties. In Y-tube choice assays, P. vigintimaculata beetles displayed a significant preference for the odors of infected plants compared to those of healthy plants. Moreover, beetles exhibited strong attraction to one individual compound, 1-octen-3-ol, which was the most abundant of the characteristic fungal compounds identified. These results enhance our understanding of the olfactory cues that guide foraging by mycophagous insects and may facilitate the development of integrated disease-management strategies informed by an understanding of underlying ecological mechanisms.

  3. Inflammatory reaction to fabric collars from percutaneous antennas attached to intracoelomic radio transmitters implanted in harlequin ducks (Histrionicus histrionicus)

    Science.gov (United States)

    Mulcahy, D.M.; Burek, K.A.; Esler, Daniel

    2007-01-01

    In wild birds implanted intracoelomically with radio transmitters, a synthetic fabric collar placed around the base of a percutaneous antenna is believed to function as a barrier to contamination of the coelom. We examined 13 fabric collars recovered from percutaneous antennas of radio transmitters implanted intracoelomically in harlequin ducks (Histrionicus histrionicus) 12 months earlier. Both the transmitters and antenna collars were encapsulated in fibrous connective tissue, with adhesions to internal organs. Histologically, bacteria were evident at the fabric-plastic interface in 8 of 10 collars examined in cross section and along the length of the collar in 3 collars examined longitudinally. Bacteria were confined within the fibrotic sheath surrounding the transmitter and the antenna collar in all birds. No evidence of chronic systemic effects secondary to implantation was present on hematologic or serum biochemical testing. These findings indicate that antenna collars do not prevent the entry of bacteria along the percutaneous antenna but may help stabilize the antenna and minimize coelomic contamination. We conclude that radio transmitters implanted into the coelom of harlequin ducks do not appear to cause significant health problems for at least 1 year after implantation.

  4. A numerical study of combined use of two biocontrol agents with different biocontrol mechanisms in controlling foliar pathogens.

    Science.gov (United States)

    Xu, X-M; Jeffries, P; Pautasso, M; Jeger, M J

    2011-09-01

    Effective use of biocontrol agents is an important component of sustainable agriculture. A previous numerical study of a generic model showed that biocontrol efficacy was greatest for a single biocontrol agent (BCA) combining competition with mycoparasitism or antibiosis. This study uses the same mathematical model to investigate whether the biocontrol efficacy of combined use of two BCAs with different biocontrol mechanisms is greater than that of a single BCA with either or both of the two mechanisms, assuming that two BCAs occupy the same host tissue as the pathogen. Within the parameter values considered, a BCA with two biocontrol mechanisms always outperformed the combined use of two BCAs with a single but different biocontrol mechanism. Similarly, combined use of two BCAs with a single but different biocontrol mechanism is shown to be far less effective than that of a single BCA with both mechanisms. Disease suppression from combined use of two BCAs was very similar to that achieved by the more efficacious one. As expected, a higher BCA introduction rate led to increased disease suppression. Incorporation of interactions between two BCAs did not greatly affect the disease dynamics except when a mycoparasitic and, to a lesser extent, an antibiotic-producing BCA was involved. Increasing the competitiveness of a mycoparasitic BCA over a BCA whose biocontrol mechanism is either competition or antibiosis may lead to improved biocontrol initially and reduced fluctuations in disease dynamics. The present study suggests that, under the model assumptions, combined use of two BCAs with different biocontrol mechanisms in most cases only results in control efficacies similar to using the more efficacious one alone. These predictions are consistent with published experimental results, suggesting that combined use of BCAs should not be recommended without clear understanding of their main biocontrol mechanisms and relative competitiveness, and experimental evaluation.

  5. Prevalence of type III secretion system in effective biocontrol pseudomonads.

    Science.gov (United States)

    Almario, Juliana; Gobbin, Davide; Défago, Geneviève; Moënne-Loccoz, Yvan; Rezzonico, Fabio

    2014-05-01

    Functional type III secretion system (T3SS) genes are needed for effective biocontrol of Pythium damping-off of cucumber by Pseudomonas fluorescens KD, but whether biocontrol Pseudomonas strains with T3SS genes display overall a higher plant-protecting activity is unknown. The assessment of 198 biocontrol fluorescent pseudomonads originating from 60 soils worldwide indicated that 32% harbour the ATPase-encoding T3SS gene hrcN, which was most often found in tomato isolates. The hrcN(+) biocontrol strains (and especially those also producing 2,4-diacetylphloroglucinol and displaying 1-aminocyclopropane-1-carboxylate deaminase activity) displayed higher plant-protecting ability in comparison with hrcN(-) biocontrol strains, both in the Pythium/cucumber and Fusarium/cucumber pathosystems.

  6. Spatial and taxonomical overlap of fungi on phylloplanes and invasive alien ladybirds with fungal infections in tree crowns of urban green spaces

    DEFF Research Database (Denmark)

    Howe, Andrew Gordon; Ravn, Hans Peter; Jensen, Annette Bruun;

    2016-01-01

    ), Lecanicillium spp. (13.6% H. axyridis; 4.8% natives), with fewer Beauveria spp. infections (2.6% H. axyridis). Molecular identification revealed B. bassiana, B. pseudobassiana, I. farinosa and L. muscarium among isolates of both tree and ladybird origin. Tilia x europaea phylloplanes support a diverse...... occurred as infections in ladybirds. Isaria spp. was most abundant on phylloplanes (mean colony forming units (CFU) per leaf ± SE, 0.33 ± 0.03) followed by Beauveria spp. (0.22 ± 0.02 CFU per leaf) and Lecanicillium spp. (0.19 ± 0.02 CFU per leaf). Densities of inoculum were higher in inner crowns...... and decreased with height, although Lecanicillium spp. peaked at 5 – 7m. Upper phylloplane surfaces harboured higher densities of Isaria spp. and Beauveria spp. than lower surfaces, whereas Lecanicillium spp. was equally distributed. Most prevalent on ladybirds were Isaria spp. (20. 6% H. axyridis; 4.8% natives...

  7. Non-competitive Inhibition of Nicotinic Acetylcholine Receptors by Ladybird Beetle Alkaloids.

    Science.gov (United States)

    Leong, Ron L; Xing, Hong; Braekman, Jean-Claude; Kem, William R

    2015-10-01

    Ladybird beetles (Family Coccinellidae) secrete an alkaloid rich venom from their leg joints that protects them from predators. Coccinellines, the major venom constituents, are alkaloids composed of three fused piperidine rings that share a common nitrogen atom. Although many coccinellines have been isolated and chemically characterized, their pharmacological properties are essentially unknown. Using radioligand binding and functional assays we investigated the actions of several coccinellines on skeletal muscle and α7 nicotinic acetylcholine receptors (nAChRs). The alkaloids were shown to displace the specific binding of tritiated piperidyl-N-(1-(2-thienyl)cyclohexyl)-3,4-piperidine ([(3)H]-TCP), which has been shown to bind deep within the ion channel of the electric fish (Torpedo) muscle nAChR. The stereoisomers precoccinelline and hippodamine (whose nitrogens are predicted to be ionized at physiological pH) and their respective analogs N-methyl-precoccinelline and N-methyl-hippodamine (whose quaternary nitrogens are permanently charged) displayed similar IC50s for inhibition of [(3)H]-TCP binding. However, the corresponding precoccinelline and hippodamine N-oxides, coccinelline and convergine (which have an electronegative oxygen bonded to an electropositive nitrogen) displayed significantly higher binding IC50s. Finally, exochomine, a dimeric coccinelline containing the hippodamine structure, displayed the highest IC50 (lowest affinity) for displacing specific [(3)H]-TCP binding. The presence of a desensitizing concentration (10(-3) M) of carbachol (CCh) had little or no effect on the affinity of the Torpedo nAChR for the three coccinellines tested. High concentrations of the coccinellid alkaloids did not affect binding of [(3)H]-cytisine to Torpedo receptor ACh binding sites. Inhibition of the alpha7 nAChR with pre-equilibrated precoccinelline was insurmountable with respect to ACh concentration. We conclude that the coccinellines bind to one or more

  8. Reinforcing and expanding the predictions of the disturbance vicariance hypothesis in Amazonian harlequin frogs: A molecular phylogenetic and climate envelope modelling approach

    OpenAIRE

    Lötters, Stefan; van der Meijden, Arie; Rödder, Dennis; Köster, Timo E.; Kraus, Tanja; La Marca, Enrique; Haddad, Célio F B; Veith, Michael

    2010-01-01

    The disturbance vicariance hypothesis (DV) has been proposed to explain speciation in Amazonia, especially its edge regions, e. g. in eastern Guiana Shield harlequin frogs (Atelopus) which are suggested to have derived from a cool-adapted Andean ancestor. In concordance with DV predictions we studied that (i) these amphibians display a natural distribution gap in central Amazonia; (ii) east of this gap they constitute a monophyletic lineage which is nested within a pre-Andean/western clade; (...

  9. Effects of Rearing Density on Survival, Growth, and Development of the Ladybird Coleomegilla maculata in Culture

    Directory of Open Access Journals (Sweden)

    Eric W. Riddick

    2015-10-01

    Full Text Available Our research focuses on developing techniques to rear ladybird beetles (Coleoptera: Coccinellidae. We evaluated the effects of rearing density on survival, growth, and development of Coleomegilla maculata. The hypothesis that a low to moderate rearing density has limited or no effects on survival and development was tested. C. maculata first instars were reared to pupae at a density of 1, 5, 10, 15, or 20 individuals per arena (2.5 cm high, 9.0 cm diameter, and 159 cm3 volume and fed powdered brine shrimp (Artemia franciscana eggs. More larvae survived at the 1 and 5 densities, but no differences were detected between the 10, 15, or 20 densities. Median survival rate was at least 90% for larvae and 100% for pupae at the 10, 15, and 20 densities. Development time, body weight, and sex ratio were unaffected by rearing density. Overall, this study suggests that C. maculata larvae can be reared successfully at a density of 20 larvae/159 cm3 (≈ 0.126 larvae/cm3 in containers provisioned with powdered A. franciscana eggs. Scaling-up the size of containers, and C. maculata density in these containers, should be possible.

  10. The effectivity of Tilletiopsis albescens in biocontrol of powdery mildew

    DEFF Research Database (Denmark)

    Knudsen, I.M.B.; Skou, J.P.

    1993-01-01

    Tilletiopsis albescens grows well on powdery mildew fungi inoculated on barley or cucumber leaves and causes collapse of the colonies. Application of ballistospores or cut mycelium was equally effective for biocontrol, and the effectiveness tended to increase exponentially with the concentration...... of germinating units (conidia and cut mycelium) applied. Seventy percent relative humidity or more is required for effective biocontrol. Two applications of T. albescens in the period from 3 days before to 3 days after inoculation with powdery mildew were more effective than one. Applications before inoculation...... or 7 days after inoculation with powdery mildew had little effect. T. albescens followed the powdery mildew as it was disseminated to uninoculated leaves, but this did not result in an effective biocontrol. The potential for using T. albescens for biocontrol of powdery mildews is discussed....

  11. Biocontrol of Rhizoctonia solani with Trichoderma Spp.

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ From over 800 fungal strains of Trichoderma Spp. , 6 strains were found to greatly inhibit the growing of Rhizocotonia solani, the pathogen of rice sheath blight in dual culture. Among them, strain T3 was the best antagonist,which reduced the growing of the pathogen by 52.54% (Table 1). In field, both the pesticide Jinggangmycin and the mixture of T1 T6 could reduce the severity of rice sheath blight(Table 2), which resulted in the increases of seed setting rate and 1000 grain weight. Because the effect of the antagonists on the control of the pathogen could be partially realized in the watery environment, studies on the biocontrol mechanism of the fungi should be strengthened to help the establishment of a best way of antagonist utilization.

  12. Protozoa Drive the Dynamics of Culturable Biocontrol Bacterial Communities.

    Science.gov (United States)

    Müller, Maren Stella; Scheu, Stefan; Jousset, Alexandre

    2013-01-01

    Some soil bacteria protect plants against soil-borne diseases by producing toxic secondary metabolites. Such beneficial biocontrol bacteria can be used in agricultural systems as alternative to agrochemicals. The broad spectrum toxins responsible for plant protection also inhibit predation by protozoa and nematodes, the main consumers of bacteria in soil. Therefore, predation pressure may favour biocontrol bacteria and contribute to plant health. We analyzed the effect of Acanthamoeba castellanii on semi-natural soil bacterial communities in a microcosm experiment. We determined the frequency of culturable bacteria carrying genes responsible for the production of the antifungal compounds 2,4-diacetylphloroglucinol (DAPG), pyrrolnitrin (PRN) and hydrogen cyanide (HCN) in presence and absence of A. castellanii. We then measured if amoebae affected soil suppressiveness in a bioassay with sugar beet seedlings confronted to the fungal pathogen Rhizoctonia solani. Amoebae increased the frequency of both DAPG and HCN positive bacteria in later plant growth phases (2 and 3 weeks), as well as the average number of biocontrol genes per bacterium. The abundance of DAPG positive bacteria correlated with disease suppression, suggesting that their promotion by amoebae may enhance soil health. However, the net effect of amoebae on soil suppressiveness was neutral to slightly negative, possibly because amoebae slow down the establishment of biocontrol bacteria on the recently emerged seedlings used in the assay. The results indicate that microfaunal predators foster biocontrol bacterial communities. Understanding interactions between biocontrol bacteria and their predators may thus help developing environmentally friendly management practices of agricultural systems.

  13. Protozoa Drive the Dynamics of Culturable Biocontrol Bacterial Communities.

    Directory of Open Access Journals (Sweden)

    Maren Stella Müller

    Full Text Available Some soil bacteria protect plants against soil-borne diseases by producing toxic secondary metabolites. Such beneficial biocontrol bacteria can be used in agricultural systems as alternative to agrochemicals. The broad spectrum toxins responsible for plant protection also inhibit predation by protozoa and nematodes, the main consumers of bacteria in soil. Therefore, predation pressure may favour biocontrol bacteria and contribute to plant health. We analyzed the effect of Acanthamoeba castellanii on semi-natural soil bacterial communities in a microcosm experiment. We determined the frequency of culturable bacteria carrying genes responsible for the production of the antifungal compounds 2,4-diacetylphloroglucinol (DAPG, pyrrolnitrin (PRN and hydrogen cyanide (HCN in presence and absence of A. castellanii. We then measured if amoebae affected soil suppressiveness in a bioassay with sugar beet seedlings confronted to the fungal pathogen Rhizoctonia solani. Amoebae increased the frequency of both DAPG and HCN positive bacteria in later plant growth phases (2 and 3 weeks, as well as the average number of biocontrol genes per bacterium. The abundance of DAPG positive bacteria correlated with disease suppression, suggesting that their promotion by amoebae may enhance soil health. However, the net effect of amoebae on soil suppressiveness was neutral to slightly negative, possibly because amoebae slow down the establishment of biocontrol bacteria on the recently emerged seedlings used in the assay. The results indicate that microfaunal predators foster biocontrol bacterial communities. Understanding interactions between biocontrol bacteria and their predators may thus help developing environmentally friendly management practices of agricultural systems.

  14. Spatial and taxonomical overlap of fungi on phylloplanes and invasive alien ladybirds with fungal infections in tree crowns of urban green spaces

    DEFF Research Database (Denmark)

    Howe, Andrew Gordon; Ravn, Hans Peter; Jensen, Annette Bruun

    2016-01-01

    Occurrence of entomopathogenic fungi on phylloplanes in Tilia x europaea crowns between 1 - 13m was assessed in urban parks. Prevalence of fungal infections in ladybirds (Coleoptera: Coccinellidae) collected from T. x europaea was assessed to determine whether fungi found on phylloplanes also occ...

  15. Development and use of a monoclonal antibody to detect semi-digested proteins of the English grain aphid, Sitobion avenae, in the guts of ladybird beetle predators

    NARCIS (Netherlands)

    Gao, S.J.; Zhou, X.R.; Pang, B.P.; Loon, van J.J.A.; Zhao, G.Q.

    2009-01-01

    A monoclonal antibody (McAb), EGA-4A9, was developed to detect the semi-digested proteins of the English grain aphid, Sitobion avenae (Fabricius) (Hemiptera: Aphididae), in predatory ladybird beetles (species of the genera Adonia, Coccinella, Hippodamia, and Propylea) using the gut homogenate of Ado

  16. Differences in thermal balance, body temperature and activity between non-melanic and melanic two-spot ladybird beetles (Adalia bipunctata) under controlled conditions

    NARCIS (Netherlands)

    de Jong, P.W.; Gussekloo, S.W.S.; Brakefield, P.M.

    1996-01-01

    The consequences of the elytral colour difference between non-melanic (red) and melanic (black) two-spot ladybirds for their thermal properties were studied by applying and testing a biophysical model. The expected differential effects of variation in transmission through the elytra, body size, widt

  17. Intraguild predation behaviour of ladybirds in semi-field experiments explains invasion success of Harmonia axyridis.

    Directory of Open Access Journals (Sweden)

    C Lidwien Raak-van den Berg

    Full Text Available Harmonia axyridis has been introduced as a biological control agent in Europe and the USA. Since its introduction, it has established and spread, and it is now regarded as an invasive alien species. It has been suggested that intraguild predation is especially important for the invasion success of H. axyridis. The aim of this study was to compare the intraguild predation behaviour of three ladybird species (Coccinella septempunctata, Adalia bipunctata, and H. axyridis. Predation behaviour was investigated in semi-field experiments on small lime trees (Tilia platyphyllos. Two fourth-instar larvae placed on a tree rarely made contact during 3-hour observations. When placed together on a single leaf in 23%-43% of the observations at least one contact was made. Of those contacts 0%-27% resulted in an attack. Harmonia axyridis attacked mostly heterospecifics, while A. bipunctata and C. septempunctata attacked heterospecifics as often as conspecifics. In comparison with A. bipunctata and C. septempunctata, H. axyridis was the most successful intraguild predator as it won 86% and 44% of heterospecific battles against A. bipunctata and C. septempunctata respectively, whilst A. bipunctata won none of the heterospecific battles and C. septempunctata won only the heterospecific battles against A. bipunctata. Coccinella septempunctata dropped from a leaf earlier and more often than the other two species but was in some cases able to return to the tree, especially under cloudy conditions. The frequency with which a species dropped did not depend on the species the larva was paired with. The results of these semi-field experiments confirm that H. axyridis is a strong intraguild predator as a consequence of its aggressiveness and good defence against predation from heterospecific species. The fact that H. axyridis is such a strong intraguild predator helps to explain its successful establishment as invasive alien species in Europe and the USA.

  18. Sexual dimorphism in the attachment ability of the ladybird beetle Coccinella septempunctata on soft substrates

    Science.gov (United States)

    Heepe, Lars; Petersen, Dennis S.; Tölle, Lisa; Wolff, Jonas O.; Gorb, Stanislav N.

    2017-01-01

    Many insects possess adhesive foot pads, which enable reliable attachment to diverse and unpredictable substrates. The function of these adhesive organs was shown to be affected by environmental conditions such as substrate roughness, chemistry, and ambient humidity. So far, the attachment ability of insects and also that of spiders and geckos has been tested on rigid substrates only. However, the natural habitats of climbing animals may provide a variety of substrate stiffness ranging from rigid rock surfaces to soft, biofilm covered substrates. In order to test the effect of different substrate stiffness on the attachment ability of insects, we have performed friction experiments with female and male ladybird beetles Coccinella septempunctata on smooth silicone elastomer substrates of different stiffness, using a centrifugal force tester. Whereas in females, the attachment ability was not affected by the substrate stiffness within the range of tested stiffness, males showed decreasing attachment ability with decreasing substrate stiffness. This sexual dimorphism in attachment ability is explained by the presence of a specialized, discoidal seta type in males, which is not present in females. It is argued that discoidal setae, when softer if compared to the substrate, may show an advantageous peak-free interfacial stress distribution when being pulled off the substrate. For such setae being stiffer if compared the substrate, they potentially show increased edge stress concentration. In this case, lower pull-off forces are expected, in agreement with the experimentally obtained results. With the present study, we demonstrate for the first time that the substrate stiffness may have an effect on the attachment ability of climbing animals, which may also be of relevance for technical and medical applications involving adhesion to soft substrates.

  19. Numerical studies of biocontrol efficacies of foliar plant pathogens in relation to the characteristics of a biocontrol agent.

    Science.gov (United States)

    Xu, X-M; Salama, N; Jeffries, P; Jeger, M J

    2010-08-01

    A previously published generic mathematic model has been used in a numerical study to understand the dynamics of foliar pathogens in relation to mechanisms, and timing and coverage of biocontrol agent (BCA) applications. With the model parameter values used, it was demonstrated that a BCA possessing either competition or induced resistance as the main mechanism of biological control was more effective in reducing disease development than a BCA with either mycoparasitism or antibiosis as its mechanism. Application coverage, ranging from 50 to 90%, had little effect on biocontrol efficacy, particularly for a BCA with competition and induced resistance as the main mechanism of biocontrol. Conversely, delayed application of BCA had more profound effects on biocontrol efficacy for those with competition or induced resistance as their main mechanism than those with mycoparasitism and antibiosis. Biocontrol efficacy was greatest for a single BCA combining competition with mycoparasitism or antibiosis. The efficacy for a single BCA combining induced resistance with competition critically depended on application time; the efficacy was greatly reduced for delayed applications. The present study suggests that development of an effective strategy for BCA application is critically dependent upon our quantitative understanding of several key biocontrol processes and their interactions. Without reliable quantitative estimation of these processes, it is impossible to make quantitative predictions about biological control and hence to optimize BCA application strategies.

  20. Tailoring biocontrol to maximize top-down effects: on the importance of underlying site fertility.

    Science.gov (United States)

    Hovick, Stephen M; Carson, Walter P

    2015-01-01

    The degree to which biocontrol agents impact invasive plants varies widely across landscapes, often for unknown reasons. Understanding this variability can help optimize invasive species management while also informing our understanding of trophic linkages. To address these issues, we tested three hypotheses with contrasting predictions regarding the likelihood of biocontrol success. (1) The biocontrol effort hypothesis: invasive populations are regulated primarily by top-down effects, predicting that increased biocontrol efforts alone (e.g., more individuals of a given biocontrol agent or more time since agent release) will enhance biocontrol success. (2) The relative fertility hypothesis: invasive populations are regulated primarily by bottom-up effects, predicting that nutrient enrichment will increase dominance by invasives and thus reduce biocontrol success, regardless of biocontrol efforts. (3) The fertility-dependent biocontrol effort hypothesis: top-down effects will only regulate invasive populations if bottom-up effects are weak. It predicts that greater biocontrol efforts will increase biocontrol success, but only in low-nutrient sites. To test these hypotheses, we surveyed 46 sites across three states with prior releases of Galerucella beetles, the most common biocontrol agents used against invasive purple loosestrife (Lythrum salicaria). We found strong support for the fertility-dependent biocontrol effort hypothesis, as biocontrol success occurred most often with greater biocontrol efforts, but only in low-fertility sites. This result held for early stage metrics of biocontrol success (higher Galerucella abundance) and ultimate biocontrol outcomes (decreased loosestrife plant size and abundance). Presence of the invasive grass Phalaris arundinacea was also inversely related to loosestrife abundance, suggesting that biocontrol-based reductions in loosestrife made secondary invasion by P. arundinacea more likely. Our data suggest that low-nutrient sites

  1. Parasitylenchus sp. (Tylenchomorpha: Allantonematidae) parasitizing field populations of Harmonia axyridis (Coleoptera: Coccinellidae)

    DEFF Research Database (Denmark)

    Harding, Susanne; Poinar, George O. Jr.; Dimitrova, Desislava V.;

    2011-01-01

    Adults of the invasive harlequin ladybird, Harmonia axyridis (Coleoptera: Coccinellidae), were found to be parasitized by nematodes (Tylenchomorpha: Allantonematidae) in Denmark. The nematodes were identified as Parasitylenchus sp. Major morphological characters of the nematodes did not differ...

  2. The roles of inoculants' carbon source use in the biocontrol of potato scab disease.

    Science.gov (United States)

    Sun, Pingping; Zhao, Xinbei; Shangguan, Nini; Chang, Dongwei; Ma, Qing

    2015-04-01

    Despite the application of multiple strains in the biocontrol of plant diseases, multistrain inoculation is still constrained by its inconsistency in the field. Nutrients, especially carbons, play an important role in the biocontrol processes. However, little work has been done on the systematic estimation of inoculants' carbon source use on biocontrol efficacies in vivo. In the present study, 7 nonpathogenic Streptomyces strains alone and in different combinations were inoculated as biocontrol agents against the potato scab disease, under field conditions and greenhouse treatments. The influence of the inoculants' carbon source use properties on biocontrol efficacies was investigated. The results showed that increasing the number of inoculated strains did not necessarily result in greater biocontrol efficacy in vivo. However, single strains with higher growth rates or multiple strains with less carbon source competition had positive effects on the biocontrol efficacies. These findings may shed light on optimizing the consistent biocontrol of plant disease with the consideration of inoculants' carbon source use properties.

  3. The demography of Atelopus decline: Harlequin frog survival and abundance in central Panama prior to and during a disease outbreak

    Directory of Open Access Journals (Sweden)

    Rebecca McCaffery

    2015-07-01

    Full Text Available Harlequin frogs (Bufonidae: Atelopus are a species-rich genus of Neotropical toads that have experienced disproportionately severe population declines and extinctions caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd. The genus Atelopus is of high conservation concern, but relatively little is known about the population dynamics and life history of the majority of species. We examined the demography of one population of Atelopus zeteki and two populations of A. varius in central Panama using three to six years of mark-recapture data collected prior to and during an outbreak of Bd. We estimated male survival probabilities prior to the arrival of Bd and sex-specific population sizes for these three populations using state-space Bayesian population models. Prior to the arrival of Bd, monthly apparent survival probabilities were higher for A. varius males than for A. zeteki males, and recaptures among years were low in both species. Abundance of both species varied over time and declined rapidly after the arrival of Bd. Male densities were generally greater than female densities, though female densities were higher or equivalent to males after the arrival of Bd. Estimates of survival and abundance over time may be explained by differences in the use of stream habitat by the two sexes and three populations, both during and between breeding seasons. These estimates provide key baseline population information that can be used to inform reintroductions from captive assurance colonies and studies of extant Atelopus populations as part of conservation and management programs.

  4. Quantitative Assessment of Current Risks to Harlequin Ducks in Prince William Sound, Alaska, from the Exxon Valdez Oil Spill

    Science.gov (United States)

    Harwell, Mark A.; Gentile, John H.; Parker, Keith R.; Murphy, Stephen M.; Day, Robert H.; Bence, A. Edward; Neff, Jerry M.; Wiens, John A.

    2012-01-01

    Harlequin Ducks (Histrionicus histrionicus) were adversely affected by the Exxon Valdez oil spill (EVOS) in Prince William Sound (PWS), Alaska, and some have suggested effects continue two decades later. We present an ecological risk assessment evaluating quantitatively whether PWS seaducks continue to be at-risk from polycyclic aromatic hydrocarbons (PAHs) in residual Exxon Valdez oil. Potential pathways for PAH exposures are identified for initially oiled and never-oiled reference sites. Some potential pathways are implausible (e.g., a seaduck excavating subsurface oil residues), whereas other pathways warrant quantification. We used data on PAH concentrations in PWS prey species, sediments, and seawater collected during 2001–2008 to develop a stochastic individual-based model projecting assimilated doses to seaducks. We simulated exposures to 500,000 individuals in each of eight age/gender classes, capturing the variability within a population of seaducks living in PWS. Doses to the maximum-exposed individuals are ∼400–4,000 times lower than chronic toxicity reference values established using USEPA protocols for seaducks. These exposures are so low that no individual-level effects are plausible, even within a simulated population that is orders-of-magnitude larger than exists in PWS. We conclude that toxicological risks to PWS seaducks from residual Exxon Valdez oil two decades later are essentially non-existent. PMID:23723680

  5. Harlequin syndrome in childhood: case report Síndrome de Arlequim na infância: relato de caso

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    Juliano de Avelar Breunig

    2012-12-01

    Full Text Available Harlequin syndrome happens in only one side of the face. In the affected half, the face does not sweat or flush even with simulation. Arms and trunk could also be affected. This condition is induced by heat, exercise and emotional factors. The article reports a case of a nine-year-old female with a 3-year history of unilateral flushing and sweating after exercise; a brief literature review is included. Despite the rarity of this syndrome, dermatologists should recognize this condition and refer these patients to ophthalmological and neurological examination.A Síndrome de Arlequim ocorre em apenas um lado da face. No metade afetada, a face não produz suor ou flushing, mesmo estimulada. Braços e tórax raramente podem ser afetados. Esta condição é geralmente induzida por calor, exercícios e fatores emocionais. O artigo relata um caso de uma menina de 9 anos de idade com uma história de 3 anos de flushing e sudorese unilaterais no rosto após exercícios e inclui uma revisão da literatura. Apesar da raridade desta síndrome, dermatologistas devem reconhecer esta condição e encaminhar estes pacientes a um exame oftalmológico e neurológico.

  6. Surgical and immediate postrelease mortality of harlequin ducks (Histrionicus histrionicus) implanted with abdominal radio transmitters with percutaneous antennae

    Science.gov (United States)

    Mulcahy, D.M.; Esler, Daniel

    1999-01-01

    Radiotelemetry is an essential tool in the study of free-ranging bird populations, and a variety of transmitter-attachment methods have been developed. A promising new method is abdominal implantation of a transmitter with a percutaneous antenna. Researchers using this technique should be concerned about and aware of mortality during surgery and during the immediate postrelease period (the 14-day period following surgery). Of 307 radio-implant surgeries performed between 1995 and 1997 in harlequin ducks (Histrionicus histrionicus), 7 (2.3%) deaths were documented during surgery or anesthetic recovery. Of 295 birds released with implanted radios, 10 (3.4%) died during the immediate postrelease period. Modifications to anesthetic procedures used in the 204 surgeries performed in 1996 and 1997 reduced mortality to 1.5% during surgery and 1.5% during the immediate postrelease period. Anesthetic modifications included intubation of all birds, placement of birds on an elevated platform that allowed the head to rest at a level lower than the body during surgery, placement of a heated water blanket under the birds during surgery, monitoring of body temperature, and use of electrocardiogram and Doppler ultrasound to monitor heart rates and arrhythmias. Low levels of mortality associated with abdominal implantation of radio transmitters may be unavoidable, but mortality can be minimized with adjustments to anesthetic technique. Copyright 1999 by American Association of Zoo Veterinarians.

  7. Methods for the Evaluation of the Bioactivity and Biocontrol Potential of Species of Trichoderma.

    Science.gov (United States)

    Steyaert, Johanna; Hicks, Emily; Kandula, Janaki; Kandula, Diwakar; Alizadeh, Hossein; Braithwaite, Mark; Yardley, Jessica; Mendoza-Mendoza, Artemio

    2016-01-01

    Members of the genus Trichoderma comprise the majority of commercial fungal biocontrol agents of plant diseases. As such, there is a wealth of information available on the analysis of their biocontrol potential and the mechanisms behind their superior abilities. This chapter aims to summarize the most common methods utilized within a Trichoderma biocontrol program for assessing the biological properties of individual strains.

  8. Vorticella sp: Prospective Mosquito Biocontrol agent

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    Chandrashekhar Devidas Patil

    2016-10-01

    Full Text Available Background: Considering the disadvantages of chemical insecticides, we aimed to evaluate Vorticella parasites for control of mosquito larvae of Anopheles stephensi and Aedes aegypti at different larval stages.Methods: Vorticella sp infected mosquito larvae were crushed in the 0.85% saline and homogenized well to get Vorti­cella in suspension. The effects of Vorticella sp infections on larval development were investigated by inoculat­ing protozoan on different larval instars of An. stephensi and Ae. aegypti and observed under light microscope. Le­thal time of the Vorticella infected larvae at different stages was calculated.Results: First and 2nd larval instars of both An. stephensi and Ae. aegypti did not show signs of infection by Vorti­cella sp., whereas 3rd instars of An. stephensi showed more Vorticella infection than those of Ae. aegypti. However, 4th larval instars of both mosquitoes were heavily infected with Vorticella parasite which was responsible for slug­gish movements of larvae and eventually death. Moreover, parasites (Vorticella spp were responsible for more than 90% reduction in adult emergence for both infected An. stephensi and Ae. aegypti.Conclusion: This study provides insights for mosquito larvicidal action of surface parasite Vorticella on different larval stages of An. stephensi and Ae. Aegypti. It could be suggested as a potential candidate in mosquito biocontrol programs.

  9. Cytochrome P4501A biomarker indication of oil exposure in harlequin ducks up to 20 years after the Exxon Valdez oil spill

    Science.gov (United States)

    Esler, Daniel; Trust, Kimberly A.; Ballachey, Brenda E.; Iverson, Samuel A.; Lewis, Tyler L.; Rizzolo, Daniel; Mulcahy, Daniel M.; Miles, A. Keith; Woodin, Bruce R.; Stegeman, John J.; Henderson, John D.; Wilson, Barry W.

    2010-01-01

    Hydrocarbon-inducible cytochrome P4501A (CYP1A) expression was measured, as ethoxyresorufin-O-deethylase (EROD) activity, in livers of wintering harlequin ducks (Histrionicus histrionicus) captured in areas of Prince William Sound, Alaska, USA, oiled by the 1989 Exxon Valdez spill and in birds from nearby unoiled areas, during 2005 to 2009 (up to 20 years following the spill). The present work repeated studies conducted in 1998 that demonstrated that in harlequin ducks using areas that received Exxon Valdez oil, EROD activity was elevated nearly a decade after the spill. The present findings strongly supported the conclusion that average levels of hepatic EROD activity were higher in ducks from oiled areas than those from unoiled areas during 2005 to 2009. This result was consistent across four sampling periods; furthermore, results generated from two independent laboratories using paired liver samples from one of the sampling periods were similar. The EROD activity did not vary in relation to age, sex, or body mass of individuals, nor did it vary strongly by season in birds collected early and late in the winter of 2006 to 2007, indicating that these factors did not confound inferences about observed differences between oiled and unoiled areas. We interpret these results to indicate that harlequin ducks continued to be exposed to residual Exxon Valdez oil up to 20 years after the original spill. This adds to a growing body of literature suggesting that oil spills have the potential to affect wildlife for much longer time frames than previously assumed.

  10. Exposure of sea otters and harlequin ducks in Prince William Sound, Alaska, USA, to shoreline oil residues 20 years after the Exxon Valdez oil spill.

    Science.gov (United States)

    Neff, Jerry M; Page, David S; Boehm, Paul D

    2011-03-01

    We assessed whether sea otters and harlequin ducks in an area of western Prince William Sound, Alaska, USA (PWS), oiled by the 1989 Exxon Valdez oil spill (EVOS), are exposed to polycyclic aromatic hydrocarbons (PAH) from oil residues 20 years after the spill. Spilled oil has persisted in PWS for two decades as surface oil residues (SOR) and subsurface oil residues (SSOR) on the shore. The rare SOR are located primarily on the upper shore as inert, nonhazardous asphaltic deposits, and SSOR are confined to widely scattered locations as small patches under a boulder/cobble veneer, primarily on the middle and upper shore, in forms and locations that preclude physical contact by wildlife and diminish bioavailability. Sea otters and harlequin ducks consume benthic invertebrates that they collect by diving to the bottom in the intertidal and subtidal zones. Sea otters also dig intertidal and subtidal pits in search of clams. The three plausible exposure pathways are through the water, in oil-contaminated prey, or by direct contact with SSOR during foraging. Concentrations of PAH in near-shore water off oiled shores in 2002 to 2005 were at background levels (<0.05 ng/L). Median concentrations of PAH in five intertidal prey species on oiled shores in 2002 to 2008 range from 4.0 to 34 ng/g dry weight, indistinguishable from background concentrations. Subsurface oil residues are restricted to locations on the shore and substrate types, where large clams do not occur and where sea otters do not dig foraging pits. Therefore, that sea otters and harlequin ducks continue to be exposed to environmentally significant amounts of PAH from EVOS 20 years after the spill is not plausible.

  11. Discovery and identification of a male-killing agent in the Japanese ladybird Propylea japonica (Coleoptera: Coccinellidae

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    Majerus Michael EN

    2010-02-01

    Full Text Available Abstract Background Endosymbionts that manipulate the reproduction of their hosts have been reported widely in invertebrates. One such group of endosymbionts is the male-killers. To date all male-killers reported are bacterial in nature, but comprise a diverse group. Ladybirds have been described as a model system for the study of male-killing, which has been reported in multiple species from widespread geographic locations. Whilst criteria of low egg hatch-rate and female-biased progenic sex ratio have been used to identify female hosts of male-killers, variation in vertical transmission efficiency and host genetic factors may result in variation in these phenotypic indicators of male-killer presence. Molecular identification of bacteria and screening for bacterial presence provide us with a more accurate method than breeding data alone to link the presence of the bacteria to the male-killing phenotype. In addition, by identifying the bacteria responsible we may find evidence for horizontal transfer between endosymbiont hosts and can gain insight into the evolutionary origins of male-killing. Phylogenetic placement of male-killing bacteria will allow us to address the question of whether male-killing is a potential strategy for only some, or all, maternally inherited bacteria. Together, phenotypic and molecular characterisation of male-killers will allow a deeper insight into the interactions between host and endosymbiont, which ultimately may lead to an understanding of how male-killers identify and kill male-hosts. Results A male-killer was detected in the Japanese coccinellid, Propylea japonica (Thunberg a species not previously known to harbour male-killers. Families produced by female P. japonica showed significantly female-biased sex ratios. One female produced only daughters. This male-killer trait was maternally inherited and antibiotic treatment produced a full, heritable cure. Molecular analysis identified Rickettsia to be associated

  12. Love as a Commodity: Brand-Name Romantic Fiction and its Readers. The Domain and Readership of Harlequin Enterprises, Both in Iceland and Abroad

    OpenAIRE

    Helena María Smáradóttir 1983

    2009-01-01

    In this thesis I explore the domain of Harlequin Enterprises, the publishing house of romantic fiction, and the company’s publication and its marketing strategies. I also look at the Icelandic market of romantic fiction and examine the readership of the Icelandic readers of brand-name romantic fiction. I seek to establish who the Icelandic readers are, explain the need that women fulfil by reading these books and why novels of romantic fiction are as popular as they are. In the first part...

  13. Potential biocontrol agents for biofouling on artificial structures.

    Science.gov (United States)

    Atalah, Javier; Newcombe, Emma M; Hopkins, Grant A; Forrest, Barrie M

    2014-09-01

    The accumulation of biofouling on coastal structures can lead to operational impacts and may harbour problematic organisms, including non-indigenous species. Benthic predators and grazers that can supress biofouling, and which are able to be artificially enhanced, have potential value as augmentative biocontrol agents. The ability of New Zealand native invertebrates to control biofouling on marina pontoons and wharf piles was tested. Caging experiments evaluated the ability of biocontrol to mitigate established biofouling, and to prevent fouling accumulation on defouled surfaces. On pontoons, the gastropods Haliotis iris and Cookia sulcata reduced established biofouling cover by >55% and largely prevented the accumulation of new biofouling over three months. On wharf piles C. sulcata removed 65% of biofouling biomass and reduced its cover by 73%. C. sulcata also had better retention and survival rates than other agents. Augmentative biocontrol has the potential to be an effective method to mitigate biofouling on marine structures.

  14. Biocontrol traits of Pseudomonas spp. are regulated by phase variation.

    Science.gov (United States)

    van den Broek, Daan; Chin-A-Woeng, Thomas F C; Eijkemans, Kevin; Mulders, Ine H M; Bloemberg, Guido V; Lugtenberg, Ben J J

    2003-11-01

    Of 214 Pseudomonas strains isolated from maize rhizosphere, 46 turned out to be antagonistic, of which 43 displayed clear colony phase variation. The latter strains formed both opaque and translucent colonies, designated as phase I and phase II, respectively. It appeared that important biocontrol traits, such as motility and the production of antifungal metabolites, proteases, lipases, chitinases, and biosurfactants, are correlated with phase I morphology and are absent in bacteria with phase II morphology. From a Tn5luxAB transposon library of Pseudomonas sp. strain PCL1171 phase I cells, two mutants exhibiting stable expression of phase II had insertions in gacS. A third mutant, which showed an increased colony phase variation frequency was mutated in mutS. Inoculation of wheat seeds with PCL1171 bacteria of phase I morphology resulted in efficient suppression of take-all disease, whereas disease suppression was absent with phase II bacteria. Neither the gacS nor the mutS mutant was able to suppress take-all, but biocontrol activity was restored after genetic complementation of these mutants. Furthermore, in a number of cases, complementation by gacS of wild-type phase II sectors to phase I phenotype could be shown. A PCL1171 phase I mutant defective in antagonistic activity appeared to have a mutation in a gene encoding a lipopeptide synthetase homologue and had lost its biocontrol activity, suggesting that biocontrol by strain PCL1171 is dependent on the production of a lipopeptide. Our results show that colony phase variation plays a regulatory role in biocontrol by Pseudomonas bacteria by influencing the expression of major biocontrol traits and that the gacS and mutS genes play a role in the colony phase variation process. Therefore phase variation not only plays a role in escaping animal defense but it also appears to play a much broader and vital role in the ecology of bacteria producing exoenzymes, antibiotics, and other secondary metabolites.

  15. No evidence that presence of sexually transmitted infection selects for reduced mating rate in the two spot ladybird, Adalia bipunctata

    Directory of Open Access Journals (Sweden)

    Sophie L. Jones

    2015-08-01

    Full Text Available Sexually transmitted infections (STIs are common in animals and plants, and frequently impair individual fertility. Theory predicts that natural selection will favour behaviours that reduce the chance of acquiring a STI. We investigated whether an STI, Coccipolipus hippodamiae has selected for increased rejection of mating by female Adalia bipunctata as a mechanism to avoid exposure. We first demonstrated that rejection of mating by females did indeed reduce the chance of acquiring the mite. We then examined whether rejection rate and mating rate differed between ladybirds from mite-present and mite-absent populations when tested in a common environment. No differences in rejection intensity or remating propensity were observed between the two populations. We therefore conclude there is no evidence that STIs have driven the evolution of female mating behaviour in this species.

  16. Use of a pollen-based diet to expose the ladybird beetle Propylea japonica to insecticidal proteins.

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    Xiaojie Zhang

    Full Text Available A rape seed pollen-based diet was developed and found to be suitable for use in a dietary exposure assay for Propylea japonica. Using the diet, we established and validated a dietary exposure assay by using the protease inhibitor E-64 as positive control. Dose-dependent responses were documented for all observed life-table parameters of P. japonica including survival, pupation and eclosion rates, development time and adult weight. Results suggested that the dietary assay can detect the effects of insecticidal compounds on the survival and development of P. japonica. Using the established dietary assay, we subsequently tested the toxicity of Cry1Ab, Cry1Ac and Cry1F proteins that are expressed by transgenic maize, cotton or rice plants to P. japonica larvae. The diet containing E-64 was included as a positive control. Survival and development of P. japonica larvae were not adversely affected when the diet contained purified Cry1Ab, Cry1Ac, or Cry1F at 500 µg/g diet representing a worst-case exposure scenario. In contrast, P. japonica larvae were adversely affected when the diet contained E-64. The bioactivity and stability of the Cry proteins in the diet and Cry protein uptake by the ladybird larvae were confirmed by bioassay with a Cry-sensitive insect species and by ELISA. The current study describes a suitable experimental system for assessing the potential effects of gut-active insecticidal compounds on ladybird beetle larvae. The experiments with the Cry proteins demonstrate that P. japonica larvae are not sensitive to Cry1Ab, Cry1Ac and Cry1F.

  17. Use of a pollen-based diet to expose the ladybird beetle Propylea japonica to insecticidal proteins.

    Science.gov (United States)

    Zhang, Xiaojie; Li, Yunhe; Romeis, Jörg; Yin, Xinming; Wu, Kongming; Peng, Yufa

    2014-01-01

    A rape seed pollen-based diet was developed and found to be suitable for use in a dietary exposure assay for Propylea japonica. Using the diet, we established and validated a dietary exposure assay by using the protease inhibitor E-64 as positive control. Dose-dependent responses were documented for all observed life-table parameters of P. japonica including survival, pupation and eclosion rates, development time and adult weight. Results suggested that the dietary assay can detect the effects of insecticidal compounds on the survival and development of P. japonica. Using the established dietary assay, we subsequently tested the toxicity of Cry1Ab, Cry1Ac and Cry1F proteins that are expressed by transgenic maize, cotton or rice plants to P. japonica larvae. The diet containing E-64 was included as a positive control. Survival and development of P. japonica larvae were not adversely affected when the diet contained purified Cry1Ab, Cry1Ac, or Cry1F at 500 µg/g diet representing a worst-case exposure scenario. In contrast, P. japonica larvae were adversely affected when the diet contained E-64. The bioactivity and stability of the Cry proteins in the diet and Cry protein uptake by the ladybird larvae were confirmed by bioassay with a Cry-sensitive insect species and by ELISA. The current study describes a suitable experimental system for assessing the potential effects of gut-active insecticidal compounds on ladybird beetle larvae. The experiments with the Cry proteins demonstrate that P. japonica larvae are not sensitive to Cry1Ab, Cry1Ac and Cry1F.

  18. Defects in Stratum Corneum Desquamation Are the Predominant Effect of Impaired ABCA12 Function in a Novel Mouse Model of Harlequin Ichthyosis

    Science.gov (United States)

    Feng, Weiguo; Hupe, Melanie; Crumrine, Debra A.; Chen, Jiang; Elias, Peter M.; Holleran, Walter M.; Niswander, Lee; Hohl, Daniel; Williams, Trevor; Torchia, Enrique C.; Roop, Dennis R.

    2016-01-01

    Harlequin Ichthyosis is a severe skin disease caused by mutations in the human gene encoding ABCA12. Here, we characterize a novel mutation in intron 29 of the mouse Abca12 gene that leads to the loss of a 5’ splice donor site and truncation of the Abca12 RNA transcript. Homozygous mutants of this smooth skin or smsk allele die perinatally with shiny translucent skin, typical of animal models of Harlequin Ichthyosis. Characterization of smsk mutant skin showed that the delivery of glucosylceramides and CORNEODESMOSIN was defective, while ultrastructural analysis revealed abnormal lamellar bodies and the absence of lipid lamellae in smsk epidermis. Unexpectedly, mutant stratum corneum remained intact when subjected to harsh chemical dissociation procedures. Moreover, both KALLIKREIN 5 and -7 were drastically decreased, with retention of desmoplakin in mutant SC. In cultured wild type keratinocytes, both KALLIKREIN 5 and -7 colocalized with ceramide metabolites following calcium-induced differentiation. Reducing the intracellular levels of glucosylceramide with a glucosylceramide synthase inhibitor resulted in decreased secretion of KALLIKREIN proteases by wild type keratinocytes, but not by smsk mutant keratinocytes. Together, these findings suggest an essential role for ABCA12 in transferring not only lipids, which are required for the formation of multilamellar structures in the stratum corneum, but also proteolytic enzymes that are required for normal desquamation. Smsk mutant mice recapitulate many of the pathological features of HI and can be used to explore novel topical therapies against a potentially lethal and debilitating neonatal disease. PMID:27551807

  19. A deficiency of apoptosis inducing factor (AIF in Harlequin mouse heart mitochondria paradoxically reduces ROS generation during ischemia-reperfusion

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    Qun eChen

    2014-07-01

    Full Text Available Background and Aims: AIF (apoptosis inducing factor is a flavin and NADH containing protein located within mitochondria required for optimal function of the respiratory chain. AIF may function as an antioxidant within mitochondria, yet when released from mitochondria it activates caspase-independent cell death. The Harlequin (Hq mouse has a markedly reduced content of AIF, providing an experimental model to query if the main role of AIF in the exacerbation of cell death is enhanced mitochondrial generation of reactive oxygen species (ROS or the activation of cell death programs. We asked if the ROS generation is altered in Hq heart mitochondria at baseline or following ischemia-reperfusion (IR.Methods: Buffer perfused mouse hearts underwent 30 min ischemia and 30 min reperfusion. Mitochondrial function including oxidative phosphorylation and H2O2 generation was measured. Immunoblotting was used to determine the contents of AIF and PAR [poly(ADP-ribose] in cell fractions.Results: There were no differences in the release of H2O2 between wild type (WT and Hq heart mitochondria at baseline. IR increased H2O2 generation from WT but not from Hq mitochondria compared to corresponding time controls. The complex I activity was decreased in WT but not in Hq mice following IR. The relocation of AIF from mitochondria to nucleus was increased in WT but not in Hq mice. IR activated PARP-1 only in WT mice. Cell injury was decreased in Hq mouse heart following in vitro IR.Conclusion: A deficiency of AIF within mitochondria does not increase ROS production during IR, indicating that AIF functions less as an antioxidant within mitochondria. The decreased cardiac injury in Hq mouse heart accompanied by less AIF translocation to the nucleus suggests that AIF relocation, rather than the AIF content within mitochondria, contributes to cardiac injury during IR.

  20. 瓢虫全年保护利用研究%Research in Year-round Protection and Utilization of Ladybirds

    Institute of Scientific and Technical Information of China (English)

    李峰; 鲁晋秀; 许玉娟; 安晓东

    2011-01-01

    已查清山西瓢虫资源共52种,其中捕食性47种,分属7亚科.通过20年监测资料分析,瓢虫与蚜害种群动态存在跟随现象;实施林带、诱集带、陪作带、秋菜园"三带一园"保护措施,保卵、保源、保转移、保越冬,取得良好效应.%There are 52 kinds of ladybirds in Shanxi Province, 47 kinds of which belongs to 7 subfamilies were in predacity. Analysis of twenty years monitoring data showed that, population dynamics of ladybirds followed that of aphids, and controlled the latter very efficiently. Carrying out forest belt, trap and attract belt, accompany cropping belt and summer vegetables garden, which defined three belts and one garden', can protect ovum and source of ladybirds, guarantee their migrates in summer, and their safety during winter.

  1. Challenges and opportunities for the commercialization of postharvest biocontrol

    Science.gov (United States)

    The past twenty years has seen the field of postharvest biocontrol evolve into a sophisticated science with global research programs worldwide, numerous yearly publications, patented technologies, and the development of new commercial products. The use of these products, however, still remains limi...

  2. Differential induction of systemic resistance in Arabidopsis by biocontrol bacteria

    NARCIS (Netherlands)

    Wees, A.C.M. van; Pieterse, C.M.J.; Trijssenaar, A.; Westende, Y.A.M. van 't; Hartog, F.; Loon, L.C. van

    1997-01-01

    Differential Induction of Systemic Resistance in Arabidopsis by Biocontrol Bacteria. Saskia C. M. Van Wees (1,2), Corné M. J. Pieterse (1,2), Annemiek Trijssenaar (1), Yvonne A. M. Van 't Westende (1), Femke Hartog (1), and Leendert C. Van Loon (1,2). (1) Department of Plant Ecology and Evolutionary

  3. Tritrophic interactions between transgenic potato expressing snowdrop lectin (GNA), an aphid pest (peach-potato aphid; Myzus persicae (Sulz.) and a beneficial predator (2-spot ladybird; Adalia bipunctata L.).

    Science.gov (United States)

    Down, Rachel E; Ford, Louise; Woodhouse, Stephen D; Davison, Gillian M; Majerus, Michael E N; Gatehouse, John A; Gatehouse, Angharad M R

    2003-04-01

    Tritrophic interactions between transgenic potato expressing the insecticidal lectin from snowdrop (Galanthus nivalis agglutinin; GNA), an aphid pest, Myzus persicae (Sulz.), and a beneficial predator, the 2-spot ladybird (Adalia bipunctata L.) were investigated. Clonal plants expressing GNA at 0.1-0.2% total soluble protein in leaves were used. No significant effects on development and survival of ladybird larvae fed on aphids from these transgenic plants were observed, with larval survival in the experimental group being 90% compared to 89% for controls. There were also no effects on subsequent female or male longevity. Female fecundity was also investigated. Although no significant differences (p > 0.05) were observed in egg production between control and experimental groups, a 10%, reduction (p < 0.01) in egg viability (determined by % hatch) occurred in ladybirds fed aphids reared on transgenic plants. Additional studies were carried out using aphids fed on artificial diet containing GNA, to deliver quantified levels of the protein to ladybird adults. GNA had no deleterious effects upon adult longevity, but resulted in a consistent trend for improved fecundity. Egg production was increased by up to 70% and egg viability also increased significantly. The results suggest that GNA is not deleterious to ladybirds. Results from these studies highlight the need to discriminate between direct and indirect effects when studying tritrophic interactions between plants/pests/natural enemies. Furthermore, it emphasises the importance of demonstrating 'cause and effect'.

  4. GMC oxidoreductase, a highly expressed protein in a potent biocontrol agent Fusarium oxysporum Cong:1-2, is dispensable for biocontrol activity.

    Science.gov (United States)

    Kawabe, Masato; Okabe Onokubo, Akiko; Arimoto, Yutaka; Yoshida, Takanobu; Azegami, Koji; Teraoka, Tohru; Arie, Tsutomu

    2011-01-01

    A spontaneous non-pathogenic variant (Cong:1-2) derived from Fusarium oxysporum f. sp. conglutinans (Cong: 1-1), a causal agent of cabbage yellows, carries biocontrol activity for cabbage yellows. We found a GMC oxidoreductase (ODX1) among the proteins expressed much more in Cong:1-2 than Cong:1-1 by 2D-DIGE comparison. GMC oxidoreductases have been reported to be involved in biocontrol activity of several plant pathogenic fungi. The gene encoding ODX1 in Cong:1-2 was cloned, and targeted disruption of the gene in Cong:1-2 did not affect its biocontrol activity, suggesting that GMC oxidoreductase is dispensable for biocontrol activity in the fungal biocontrol agent.

  5. First record and bionomics of the mycophagous ladybird Psyllobora bisoctonotata (Mulsant (Coleoptera: Coccinellidae in Sudan

    Directory of Open Access Journals (Sweden)

    Abdalla Abdelrahim Satti

    2015-01-01

    Full Text Available Powdery mildews caused by several fungi, particularly of the genera Erysiphe, Sphaerotheca and Leveillula, are destructive diseases of various cultivated and wild plants during winter season (December–March in Sudan. Application of synthetic fungicides is the only control measure practiced. Fortuitously, during a field survey, congregations of coccinellid adults and grubs were found associated with powdery mildews on a wild plant, Xanthium brasilicum Vell., locally known as “Ramtouk”, at Shambat area/Khartoum North. Therefore, the insect was subjected to some bionomical studies conducted during winter season 2011/12. Emphasis was devoted to morphometric investigations, supported with life cycle durations and seasonal trend on the foregoing host. Accordingly, the species was recognized as Psyllobora bisoctonotata (Muls., a well known powdery mildew feeder in several countries. This is the first record of a mycophagous insect in Sudan. Hence, the important morphological features of the different stages were presented. The rearing of the insect on powdery mildew infected Ramtouk leaves in the laboratory (27.50 ± 3.75 °C and 15.83 ± 3.82% R.H. revealed that the mean total lifecycle from egg to adult was 25.28 ± 1.57 days. The insect appeared on X. brasilicum in a very small number in December, peaked in February, and then gradually declined thereafter coinciding with an increase in temperature and a decrease in powdery mildew infection. So far, the real distribution of this mycophagous species and its host range are waiting for more investigations. Meticulous bio-ecological studies are important to ascertain the proper habitat for such insect throughout the year, and to evaluate its potential role as a biocontrol agent for the powdery mildews.

  6. Biology of the harlequin fish Othos dentex (Serranidae), with particular emphasis on sexual pattern and other reproductive characteristics.

    Science.gov (United States)

    French, B; Potter, I C; Hesp, S A; Coulson, P G; Hall, N G

    2014-01-01

    Key biological characteristics of the harlequin fish Othos dentex, a representative of a monospecific genus of the Anthiinae (Serranidae), were determined from samples collected around reefs on the south coast of Western Australia. The females of this relatively long-lived species (maximum recorded age in this study = 37 years) attained only a slightly greater maximum total length and age than males and neither the length nor the age-frequency distributions showed a conspicuous sex-based bimodality. Furthermore, gonads from a wide size and age range of O. dentex were shown by histology, at several locations along their length, to always comprise exclusively either ovarian or testicular tissues. Thus, O. dentex is a gonochorist, a sexual pattern only previously recorded definitively for one other anthiine serranid, i.e. Epinephelides armatus, which also occurs in south-western Australia. Similar to E. armatus, O. dentex possesses 'solid' testes with a central sperm duct, thereby differing in structure from those typically found in serranids, in which there is a central membrane-bound 'ovarian' lumen and peripherally located sperm sinuses. The gonadal characteristics and sexual pattern of these two gonochoristic anthiines are not consistent with a recent proposal for the trends exhibited by the evolution of gonochorism and protogyny within the Serranidae. Othos dentex has indeterminate fecundity and a protracted spawning period (7 months) and, on the basis of underwater observations and a low gonado-somatic index (I(G)) for males, is a pair spawner, which is unusual for a gonochorist of a serranid or member of a related family. While the large spots on the lower half of the body of O. dentex are shown quantitatively to be similarly yellow in juveniles and adult females, they then become blue in males at maturity and this intensifies during the spawning period, when they presumably play an important role in agonistic interactions among males and courtship with

  7. Phages of Listeria offer novel tools for diagnostics and biocontrol

    Directory of Open Access Journals (Sweden)

    Martin J Loessner

    2014-04-01

    Full Text Available Historically, bacteriophages infecting their hosts have perhaps been best known and even notorious for being a nuisance in dairy-fermentation processes. However, with the rapid progress in molecular microbiology and microbial ecology, a new dawn has risen for phages. This review will provide an overview on possible uses and applications of Listeria phages, including phage-typing, reporter phage for bacterial diagnostics, and use of phage as biocontrol agents for food safety. The use of phage-encoded enzymes such as endolysins for the detection and as antimicrobial will also be addressed. Desirable properties of candidate phages for biocontrol will be discussed. While emphasizing the enormous future potential for applications, we will also consider some of the intrinsic limitations dictated by both phage and bacterial ecology.

  8. Viral biocontrol: grand experiments in disease emergence and evolution.

    Science.gov (United States)

    Di Giallonardo, Francesca; Holmes, Edward C

    2015-02-01

    Although viral emergence is commonly associated with cross-species transmission, the processes and determinants of viral evolution in a novel host environment are poorly understood. We address key questions in virus emergence and evolution using data generated from two unique natural experiments: the deliberate release of myxoma virus (MYXV) and rabbit hemorrhagic disease virus (RHDV) as biological control (biocontrol) agents against the European rabbit in Australia, and which have been of enormous benefit to Australia's ecosystem and agricultural industries. Notably, although virulence evolution in MYXV and RHDV followed different trajectories, a strongly parallel evolutionary process was observed in Australia and Europe. These biocontrol agents were also characterized by a lack of transmission to nontarget host species, suggesting that there are major barriers to successful emergence.

  9. Novel routes for improving biocontrol activity of Bacillus based bioinoculants

    Directory of Open Access Journals (Sweden)

    Liming eWu

    2015-12-01

    Full Text Available Biocontrol formulations prepared from plant-growth-promoting bacteria are increasingly applied in sustainable agriculture. Especially inoculants prepared from endospore-forming Bacillus strains have been proven as efficient and environmental-friendly alternative to chemical pesticides due to their long shelf life, which is comparable with that of agrochemicals. However, these formulations of the first generation are sometimes hampered in their action and do not fulfill in each case the expectations of the appliers. In this review we use the well-known plant-associated Bacillus amyloliquefaciens type strain FZB42 as example for the successful application of different techniques offered today by comparative, evolutionary and functional genomics, site-directed mutagenesis and strain construction including marker removal, for paving the way for preparing a novel generation of biocontrol agents.

  10. Bioprospection of yeasts as biocontrol agents against phytopathogenic molds

    Directory of Open Access Journals (Sweden)

    Márcia Maria Rosa-Magri

    2011-02-01

    Full Text Available Yeasts isolated from sugar cane and maize rhizosphere, leaves and stalks were screened against the phytopathogenic molds Colletotrichum sublineolum and Colletotrichum graminicola, both causal agents of the anthracnose disease in sorghum and maize, respectively. Strains identified as Torulaspora globosa and Candida intermedia were able to inhibit the mold growth, with the first species also exhibiting killer activity. No previous report on the application and potentiality of these yeasts as biocontrol agents were found neither the killer phenotype in Torulaspora globosa.

  11. Does a Change from Whole to Powdered Food (Artemia franciscana eggs Increase Oviposition in the Ladybird Coleomegilla maculata?

    Directory of Open Access Journals (Sweden)

    Eric W. Riddick

    2015-09-01

    Full Text Available The limited availability of alternative foods to replace natural prey hinders cost-effective mass production of ladybird beetles for augmentative biological control. We compared the effects of powdered vs. whole Artemia franciscana (A. franciscana (brine shrimp eggs with or without a dietary supplement on development and reproduction of Coleomegilla maculata (C. maculata (Coleoptera: Coccinellidae. We tested the hypotheses that (1 powdered A. franciscana eggs are more suitable than whole eggs; and (2 palmitic acid, a common fatty acid in natural prey, i.e., aphids, is an effective dietary supplement. Development time, pre-imaginal survival, sex ratio, and body weight of adults did not differ significantly amongst individuals fed powdered vs. whole eggs, with or without 5% palmitic acid. Significantly more oviposition occurred when females were fed powdered eggs than whole eggs and powdered eggs with 5% palmitic acid than whole eggs with or without 5% palmitic acid. A weak functional relationship was found between pre-oviposition time and total oviposition by females fed powdered eggs with 5% palmitic acid; pre-oviposition time decreased as oviposition increased. Food treatments had no significant differential effect on progeny (egg hatch rate. In conclusion, a simple change in A. franciscana egg texture and particle size (i.e., blending whole eggs into a dust-like powder increases oviposition in C. maculata. Supplementing powdered eggs with 5% palmitic acid might accelerate oogenesis (egg maturation in some females.

  12. Burkholderia cepacia XXVI siderophore with biocontrol capacity against Colletotrichum gloeosporioides.

    Science.gov (United States)

    de Los Santos-Villalobos, Sergio; Barrera-Galicia, Guadalupe Coyolxauhqui; Miranda-Salcedo, Mario Alberto; Peña-Cabriales, Juan José

    2012-08-01

    Colletotrichum gloeosporioides is the causal agent of anthracnose in mango. Burkholderia cepacia XXVI, isolated from mango rhizosphere and identified by 16S rDNA sequencing as a member of B. cepacia complex, was more effective than 6 other mango rhizosphere bacteria in inhibiting the model mango pathogen, C. gloeosporioides ATCC MYA 456. Biocontrol of this pathogen was demonstrated on Petri-dishes containing PDA by > 90 % reduction of surface colonization. The nature of the biocontrol metabolite(s) was characterized via a variety of tests. The inhibition was almost exclusively due to production of agar-diffusible, not volatile, metabolite(s). The diffusible metabolite(s) underwent thermal degradation at 70 and 121 °C (1 atm). Tests for indole acetic acid production and lytic enzyme activities (cellulase, glucanase and chitinase) by B. cepacia XXVI were negative, indicating that these metabolites were not involved in the biocontrol effect. Based on halo formation and growth inhibition of the pathogen on the diagnostic medium, CAS-agar, as well as colorimetric tests we surmised that strain XXVI produced a hydroxamate siderophore involved in the biocontrol effect observed. The minimal inhibitory concentration test showed that 0.64 μg ml(-1) of siderophore (Deferoxamine mesylate salt-equivalent) was sufficient to achieve 91.1 % inhibition of the pathogen growth on Petri-dishes containing PDA. The biocontrol capacity against C. gloeosporioides ATCC MYA 456 correlated directly with the siderophore production by B. cepacia XXVI: the highest concentration of siderophore production in PDB on day 7, 1.7 μg ml(-1) (Deferoxamine mesylate salt-equivalent), promoted a pathogen growth inhibition of 94.9 %. The growth of 5 additional strains of C. gloeosporioides (isolated from mango "Ataulfo" orchards located in the municipality of Chahuites, State of Oaxaca in Mexico) was also inhibited when confronted with B. cepacia XXVI. Results indicate that B. cepacia XXVI or its

  13. Three encochitinase-encoding genes identified in the biocontrol fungus Clonostachys rosea are differentially expressed

    DEFF Research Database (Denmark)

    Mamarabadi, Mojtaba; Jensen, Birgit; Lübeck, Mette

    2008-01-01

    . rosea were made by disruption of the endochitinase genes via Agrobacterium-mediated transformation and their biocontrol activity was evaluated. While in planta bioassays showed no significant difference in biocontrol efficacy between the disruptants and the wildtype, the real time RT-PCR analysis showed...

  14. Advances in biocontrol mechanism and application of Trichoderma spp. for plant diseases

    Institute of Scientific and Technical Information of China (English)

    HUANG Caihong; YANG Qian

    2007-01-01

    Trichoderma spp. is a filamentous soil fungus known as an effective biocontrol agent of a range of important airborne and soilborne pathogens, it has universal distribution and economic importance. This article reviewed the researches on biocontrol mechanism for plant diseases and application of Trichoderma spp., especially Trichoderma harzianum in recent years.

  15. Discovery of secondary metabolites from Bacillus spp. biocontrol strains using genome mining and mass spectroscopy

    Science.gov (United States)

    Genome sequencing, data mining and mass spectrometry were used to identify secondary metabolites produced by several Bacillus spp. biocontrol strains. These biocontrol strains have shown promise in managing Fusarium head blight in wheat. Draft genomes were produced and screened in silico using genom...

  16. Potencialidade antagonística detectada em alguns procariotas agentes de biocontrole de enfermidades de plantas Antagonistic potentiality in prokaryotic biocontrol agents for plant diseases

    Directory of Open Access Journals (Sweden)

    Victor Rafael Barra

    2008-06-01

    Full Text Available Ao longo de vários anos, no Laboratório de Bacteriologia de Plantas e Controle Biológico (LBPCB do Departamento de Fitopatologia da Universidade Federal de Viçosa têm-se, sistematicamente, isolado, de rizosfera, rizoplano e filoplano de plantas cultivadas de importância econômica, milhares de procariotas os quais são testados, um a um, como agentes de biocontrole de enfermidades. A grande maioria deles, como esperado, não exibe qualquer potencialidade como agente de biocontrole e é descartada. Alguns poucos são selecionados, através de demorados ensaios de biocontrole experimental tanto em casa de vegetação como em campo. Neste trabalho, mostra-se que muitos dos organismos em estudo, mesmo havendo sido selecionados, principalmente, por induzirem resistência sistêmica na planta alvo, expressam constitutivamente mecanismos de antagonismo microbiano que parecem fazer parte de seu perfil enquanto agentes de biocontrole.Along several years, at the Laboratory of Plant Bacteriology and Biological Control of the Department of Plant Pathology of the Federal University of Viçosa, thousands of prokaryote isolates have been obtained from the rhizosphere, rhizoplane and phylloplane of economically important plants. Every obtained isolate is tested as biocontrol agents. As expected, the majority does not show any biocontrol potentiality and is discarded. Few are selected through time-consuming experimental biocontrol trials in greenhouse and field. Even being selected mainly for their ability to induce resistance in target plants, many of them constitutively express mechanisms of antagonism against pathogens that seem to be part of their performance while biocontrol agents.

  17. The Homeodomain Protein Ladybird Late Regulates Synthesis of Milk Proteins during Pregnancy in the Tsetse Fly (Glossina morsitans)

    Science.gov (United States)

    Attardo, Geoffrey M.; Benoit, Joshua B.; Michalkova, Veronika; Patrick, Kevin R.; Krause, Tyler B.; Aksoy, Serap

    2014-01-01

    Regulation of tissue and development specific gene expression patterns underlies the functional specialization of organs in multi-cellular organisms. In the viviparous tsetse fly (Glossina), the female accessory gland is specialized to generate nutrients in the form of a milk-like secretion to support growth of intrauterine larva. Multiple milk protein genes are expressed specifically in the female accessory gland and are tightly linked with larval development. Disruption of milk protein synthesis deprives developing larvae of nutrients and results in extended larval development and/or in abortion. The ability to cause such a disruption could be utilized as a tsetse control strategy. Here we identify and delineate the regulatory sequence of a major milk protein gene (milk gland protein 1:mgp1) by utilizing a combination of molecular techniques in tsetse, Drosophila transgenics, transcriptomics and in silico sequence analyses. The function of this promoter is conserved between tsetse and Drosophila. In transgenic Drosophila the mgp1 promoter directs reporter gene expression in a tissue and stage specific manner orthologous to that of Glossina. Analysis of the minimal required regulatory region of mgp1, and the regulatory regions of other Glossina milk proteins identified putative homeodomain protein binding sites as the sole common feature. Annotation and expression analysis of Glossina homeodomain proteins identified ladybird late (lbl) as being accessory gland/fat body specific and differentially expressed between lactating/non-lactating flies. Knockdown of lbl in tsetse resulted in a significant reduction in transcript abundance of multiple milk protein genes and in a significant loss of fecundity. The role of Lbl in adult reproductive physiology is previously unknown. These results suggest that Lbl is part of a conserved reproductive regulatory system that could have implications beyond tsetse to other vector insects such as mosquitoes. This system is critical

  18. Establishment of transgenic lines for jumpstarter method using a composite transposon vector in the ladybird beetle, Harmonia axyridis.

    Directory of Open Access Journals (Sweden)

    Hisashi Kuwayama

    Full Text Available In this post-genomic era, genome-wide functional analysis is indispensable. The recent development of RNA interference techniques has enabled researchers to easily analyze gene function even in non-model organisms. On the other hand, little progress has been made in the identification and functional analyses of cis-regulatory elements in non-model organisms. In order to develop experimental platform for identification and analyses of cis-regulatory elements in a non-model organism, in this case, the ladybird beetle, Harmonia axyridis, we established transgenic transposon-tagged lines using a novel composite vector. This vector enables the generation of two types of insertion products (jumpstarter and mutator. The jumpstarter portion carries a transposase gene, while the mutator segment carries a reporter gene for detecting enhancers. The full-composite element is flanked by functional termini (required for movement; however, the mutator region has an extra terminus making it possible for the mutator to remobilize on its own, thus leaving an immobile jumpstarter element behind. Each insertion type is stable on its own, but once crossed, jumpstarters can remobilize mutators. After crossing a jumpstarter and mutator line, all tested G2 females gave rise to at least one new insertion line in the next generation. This jumping rate is equivalent to the P-element-mediated jumpstarter method in Drosophila. These established transgenic lines will offer us the ideal experimental materials for the effective screening and identification of enhancers in this species. In addition, this jumpstarter method has the potential to be as effective in other non-model insect species and thus applicable to any organism.

  19. The homeodomain protein ladybird late regulates synthesis of milk proteins during pregnancy in the tsetse fly (Glossina morsitans.

    Directory of Open Access Journals (Sweden)

    Geoffrey M Attardo

    2014-04-01

    Full Text Available Regulation of tissue and development specific gene expression patterns underlies the functional specialization of organs in multi-cellular organisms. In the viviparous tsetse fly (Glossina, the female accessory gland is specialized to generate nutrients in the form of a milk-like secretion to support growth of intrauterine larva. Multiple milk protein genes are expressed specifically in the female accessory gland and are tightly linked with larval development. Disruption of milk protein synthesis deprives developing larvae of nutrients and results in extended larval development and/or in abortion. The ability to cause such a disruption could be utilized as a tsetse control strategy. Here we identify and delineate the regulatory sequence of a major milk protein gene (milk gland protein 1:mgp1 by utilizing a combination of molecular techniques in tsetse, Drosophila transgenics, transcriptomics and in silico sequence analyses. The function of this promoter is conserved between tsetse and Drosophila. In transgenic Drosophila the mgp1 promoter directs reporter gene expression in a tissue and stage specific manner orthologous to that of Glossina. Analysis of the minimal required regulatory region of mgp1, and the regulatory regions of other Glossina milk proteins identified putative homeodomain protein binding sites as the sole common feature. Annotation and expression analysis of Glossina homeodomain proteins identified ladybird late (lbl as being accessory gland/fat body specific and differentially expressed between lactating/non-lactating flies. Knockdown of lbl in tsetse resulted in a significant reduction in transcript abundance of multiple milk protein genes and in a significant loss of fecundity. The role of Lbl in adult reproductive physiology is previously unknown. These results suggest that Lbl is part of a conserved reproductive regulatory system that could have implications beyond tsetse to other vector insects such as mosquitoes. This

  20. Modulation of Human Immune Response by Fungal Biocontrol Agents

    Science.gov (United States)

    Konstantinovas, Cibele; de Oliveira Mendes, Tiago A.; Vannier-Santos, Marcos A.; Lima-Santos, Jane

    2017-01-01

    Although the vast majority of biological control agents is generally regarded as safe for humans and environment, the increased exposure of agriculture workers, and consumer population to fungal substances may affect the immune system. Those compounds may be associated with both intense stimulation, resulting in IgE-mediated allergy and immune downmodulation induced by molecules such as cyclosporin A and mycotoxins. This review discusses the potential effects of biocontrol fungal components on human immune responses, possibly associated to infectious, inflammatory diseases, and defective defenses. PMID:28217107

  1. Introducing the term 'Biocontrol Plants' for integrated pest management

    Directory of Open Access Journals (Sweden)

    Pia Parolin

    2014-02-01

    Full Text Available Studies of interactions between crops, additional plants, pests and beneficial organisms already exist as well as studies of natural enemy preference, dispersal, and abundance. However, these studies focus on tri-trophic interactions from an "arthropod" point of view. We think that in order to optimize crop protection methods we need to understand the effects that plant structures have on the various arthropods and on subsequent tri-trophic interactions. Although studies and reviews describing the role of secondary plants in Integrated Pest Management (IPM exist, to date a general term which encompasses all plants added to a cropping system with the aim of enhancing IPM strategies has yet to be formulated. Therefore, we suggest a new term, "biocontrol plants", which we define as plants that are intentionally added to a crop system with the aim of enhancing crop productivity through pest attraction and/or pest regulation; a term that will promote the use of biocontrol services, and can ultimately lead to an increase in the sustainability of cropping systems.

  2. Indigenous bacteria may interfere with the biocontrol of plant diseases

    Science.gov (United States)

    Someya, Nobutaka; Akutsu, Katsumi

    2009-06-01

    Prodigiosin is a reddish antibiotic pigment that plays an important role in the biocontrol of plant diseases by the bacterium Serratia marcescens. However, its activity is unstable under agricultural conditions; further, it can be degraded by various environmental factors. To examine the effect of epiphytic microbes on the stability of prodigiosin used for biological control processes, we collected a total of 1,280 bacterial isolates from the phylloplane of cyclamen and tomato plants. Approximately 72% of the bacterial strains isolated from the cyclamen plants and 66% of those isolated from the tomato plants grew on minimal agar medium containing 100 μg ml-1 prodigiosin. Certain isolates obtained from both plant species exhibited prodigiosin-degrading activity. We compared the 16S rRNA gene sequences derived from the isolates with sequences in a database. The comparison revealed that the sequences determined for the prodigiosin-degrading isolates were homologous to those of the genera Pseudomonas, Caulobacter, Rhizobium, Sphingomonas, Janthinobacterium, Novosphingobium, and Rathayibacter. These results indicate that indigenous epiphytic microorganisms may interfere with the interaction between plant pathogens and biocontrol agents by degrading the antibiotics produced by the agents.

  3. Biocontrol of Fusarium circinatum Infection of Young Pinus radiata Trees

    Directory of Open Access Journals (Sweden)

    Eugenia Iturritxa

    2017-01-01

    Full Text Available Pitch canker, caused by the fungus Fusarium circinatum, is a major disease of Pinus radiata currently controlled to some extent in nurseries by good hygiene and application of synthetic fungicides. The aim of this study was to evaluate alternative strategies to control fungal infections in nurseries and young pine plantations. The antagonistic effects of biocontrol bacteria and essential oils against F. circinatum in vitro and in young P. radiata trees were assessed. Pseudomonas fluorescens, Erwinia billingiae, and Bacillus simplex reduced the growth of the fungus in vitro by 17%–29%, and decreased the density of the mycelial mat. In young P. radiata trees, the length of F. circinatum lesions was reduced by 22%–25% by the same bacterial strains. Direct application of cinnamon and/or clove essential oils to wounds in stems of two-year-old P. radiata trees also limited the damage caused by F. circinatum. Lesion length was reduced by 51% following treatment with cinnamon oil (10% v/v, and by 45% following treatment with clove oil (15% v/v or a combination of both oils. However, the oils were toxic to younger trees. The biocontrol bacteria and essential oils show promise as prophylactic treatments to reduce the devastating effects of F. circinatum on P. radiata.

  4. Biocontrol of postharvest Rhizopus decay of peaches with Pichia caribbica.

    Science.gov (United States)

    Xu, Baitian; Zhang, Hongyin; Chen, Keping; Xu, Qin; Yao, Yao; Gao, Hui

    2013-08-01

    A new yeast antagonist, Pichia caribbica, isolated in our laboratory from the soil collected from unsprayed orchards, was evaluated for its biocontrol capability against Rhizopus stolonifer on peaches and the possible mechanisms involved. The decay incidence and lesion diameter of Rhizopus decay of peaches treated by P. caribbica were significantly reduced compared with the control fruits, and the higher the concentration of P. caribbica, the better the efficacy of the biocontrol. Rapid colonization of the yeast in peach wounds stored at 25 °C was observed. In peaches, the activities of peroxidase (POD), catalase (CAT), and phenylalanine ammonia-lyase (PAL) were significantly induced by P. caribbica treatment compared to those of the control fruits. All these results indicated that P. caribbica has a great potential for the development of commercial formulations to control postharvest Rhizopus decay of peaches. Its modes of action were based on competition for space and nutrients with pathogens, inducement of activities of defense-related enzymes such as POD, CAT, and PAL of peaches.

  5. Interspecific Competition Among Three Predacious Ladybirds (Coleoptera: Coccinelildae)%三种捕食性瓢虫的种间竞争作用

    Institute of Scientific and Technical Information of China (English)

    王甦; 谭晓玲; 徐红星; 张帆

    2012-01-01

    [目的]明确多种捕食性天敌田间混合释放后的种群动态,探索瓢虫种间干扰的行为学基础和在生态位上的竞争关系.[方法]在田间农业生态系统中混合释放异色瓢虫、龟纹瓢虫及多异瓢虫,对种群发展动态连续监测;在室内对3种瓢虫的1龄幼虫对卵及4龄幼虫之间互残现象进行观察;对自然生境中3种瓢虫的猎物资源进行确认和资源等级划分,并计算各瓢虫的生态位宽度及生态位重叠系数.[结果]3种捕食性瓢虫在混合种群释放后个体数量均线性上升,异色瓢虫的上升速率显著大于其余2种瓢虫.各瓢虫均倾向于取食异种瓢虫的卵和幼虫,其中异色瓢虫攻击取食卵的能力显著大于其余2种瓢虫.异色瓢虫4龄幼虫在互残后的存活数量显著大于其余2种瓢虫,且伤残比例仅为龟纹瓢虫的22.3%及多异瓢虫的29.8%.基于田间观测结果,异色瓢虫共取食17种猎物,占总量89.5%,龟纹瓢虫共取食12种猎物,占总量的63.2%,多异瓢虫共取食9种猎物,占总量的47.4%.计算异色瓢虫、龟纹瓢虫和多异瓢虫的生态位宽度分别为0.713,0.393和0.304;所得生态位重叠系数异色瓢虫与龟纹瓢虫为0.992,龟纹瓢虫与多异瓢虫为0.983,异色瓢虫与多异瓢虫为0.964.[结论]异色瓢虫与其它捕食性瓢虫在田间释放时表现出很强的竞争作用.异色瓢虫可以通过较高的种间互残及攻击防御能力提高自身在营养水平低下情况时的生存概率.异色瓢虫的生态位宽度高,且与其它瓢虫的生态位重叠程度大.因此异色瓢虫的存在会严重影响同生态位其它捕食性瓢虫的种群增长.%[Objective] The objective of this study is to determine the population dynamics of various predacious ladybird beetles after mixed releasing in the field, the behavioural bases in interspecific disturbance and the interspecific competition in niche level. [Method] The population dynamics

  6. Risk assessment: progress of quarantine biocontrol research on Chinese Tallow, Melaleuca, and Downy Rose Myrtle

    Science.gov (United States)

    Risk assessments of two biocontrol candidates for Chinese tallow, Triadica sebifera (Euphoriales: Euphorbiaceae), and one for Melaleuca, Melaleuca quinquenervia (Myrtales: Myrtaceae), were conducted during 2009 and continuing into 2010 by USDA scientists located at the Florida Department of Agricul...

  7. Differential effects of organic compounds on cucumber damping-off and biocontrol activity of antagonistic bacteria

    DEFF Research Database (Denmark)

    Li, Bin; Ravnskov, Sabine; Guanlin, X.;

    2011-01-01

    The influence of the organic compounds tryptic soy broth, cellulose, glucose and chitosan on cucumber damping-off caused by Pythium aphanidermatum and biocontrol efficacy of the biocontrol agents (BCAs) Paenibacillus macerans and P. polymyxa were examined in a seedling emergence bioassay. Results...... showed that the organic compounds differentially affected both pathogen and BCAs. Tryptic soy broth, glucose and chitosan increased Pythium damping-off of cucumber, compared to the control treatment without organic compounds, whereas cellulose had no effect. Both Paenibacillus species had biocontrol...... effects against Pythium damping-off compared with the corresponding treatments with P. aphanidermatum alone, but the biocontrol efficacy depended on the type of organic compounds added. Both BCAs counteracted damping-off in treatments with TSB and chitosan. However, P. polymyxa counteracted damping...

  8. Production of a biocontrol agent for crucifers black rot disease

    Directory of Open Access Journals (Sweden)

    C.L. Luna

    2002-04-01

    Full Text Available Of nine epiphytic isolates of the genus Bacillus, only B. subtilis R14, B. pumilus C116, B. megaterium pv. cerealis RAB7, and B. cereus C210 showed antibiotic activity when tested in vitro against the bacterium Xanthomonas campestris pv. campestris LFR-3. Aiming product a biocontrol agent for black rot in crucifers, the production of B. subtilis R14 was evaluated in a batch bioreactor. Rapid growth was observed in a medium containing molasses and yeast extract as C-source and N-source, respectively. During the exponential growth phase, the specific growth rate was 1.2 h-1. A quick sporulation was also observed in a C/N well-balanced medium. After the sporulation phase, maximum viable spore concentrations around 10(9 CFU/mL were obtained. Preliminary sedimentation tests at different pH values showed better biomass separation efficiencies at low pH values.

  9. Endophytic Bacteria as Biocontrol Agents of Tomato Bacterial Wilt Disease

    Directory of Open Access Journals (Sweden)

    Arika Purnawati

    2014-01-01

    Full Text Available Ralstonia solanacearum is a tomato pathogen causing wilt disease which can lose crop production up to 100%. This problem also has economical impact to Indonesia, though controlling this pathogen has been donebefore. Biological control using endophytic bacteria is one of alternative control methods to support agriculture sustainability. The objective of these experiments are isolating endophytic bacteria taken from healthy tomato stems and root as well as investigating patogens as biocontrol agents of tomato bacterial wilt disease. Among 10 isolates found, only Ps1 and Ps8 can inhibit R. solanacearum based on antagonistic test in vitro using seed coat method and 4-7 mm inhibition zone forming. In vivo test was applied in green house in 30 days old of tomatoes usingendophytic bacteria by theroot soak technique. The result shows Ps1 and Ps8 within 15-16 days incubation period have suppressed 8.07%-9.19% pathogen attack.

  10. Biocontrol of fouling pests: Effect of diversity, identity and density of control agents.

    Science.gov (United States)

    Atalah, Javier; Newcombe, Emma M; Zaiko, Anastasija

    2016-04-01

    Augmentative biocontrol, using native natural enemies, has been suggested as a promising tool to control marine biofouling pests on artificial structures. However, there are still important knowledge gaps to be addressed before biocontrol can be considered as a management tool. In a field experiment on floating marine structures we examined intra- and interspecific consumer interactions among biocontrol agents on different surface orientations. We tested the effect of identity, density and diversity of three invertebrates (the 11-arm seastar Coscinasterias muricata, the sea urchin Evechinus chloroticus and the gastropod Cook's turban Cookia sulcata) to reduce established biofouling and to prevent fouling growth on defouled surfaces. High densities of biocontrol agents were not more effective at fouling control (cover and biomass) than low densities. Nor did multi-species treatments function more effectively than mono-specific ones. However, biocontrol agent identity was important, with the 11-arm seastar and Cook's turban being the most effective at fouling reduction and prevention, respectively. Surface orientation had a strong effect on the effectiveness of control agents, with the best results obtained on vertical compared to diagonal and underside surfaces. This study confirmed the potential of biocontrol as a management tool for marine pest, indicating that identity is more important than richness and density of control agents. It also highlighted the limitations of this approach on diagonal and underside surfaces, where control agents have limited retention ability.

  11. Biocontrol Activity of the Local Strain of Metschnikowia pulcherrima on Different Postharvest Pathogens.

    Science.gov (United States)

    Türkel, Sezai; Korukluoğlu, Mihriban; Yavuz, Mümine

    2014-01-01

    The strains of the yeast Metschnikowia pulcherrima have strong biocontrol activity against various microorganisms. Biocontrol activity of M. pulcherrima largely depends on its iron immobilizing pigment pulcherrimin. Biocontrol activity of pulcherrimin producing strain, M. pulcherrima UMY15, isolated from local vineyards, was tested on different molds that cause food spoilage. M. pulcherrima UMY15 was a very effective biocontrol agent against Penicillium roqueforti, P. italicum, P. expansum, and Aspergillus oryzae in in-vitro plate tests. However, the inhibitory activity of M. pulcherrima UMY15 was less effective on Fusarium sp. and A. niger species in biocontrol assays. In addition, M. pulcherrima UMY15 strain completely inhibited the germination and mycelia growth of A. oryzae, A. parasiticus, and Fusarium sp. spores on artificial wounds of apples when they coinoculated with M. pulcherrima UMY15. Moreover, when coinoculated, M. pulcherrima UMY15 strain also inhibited the growth of P. roqueforti, P. italicum, P. expansum, A. oryzae, Fusarium sp., and Rhizopus sp. in grape juice, indicating that M. pulcherrima UMY15 can be used as a very effective biocontrol yeast against various species of postharvest pathogens, including Penicillium, Aspergillus, Fusarium, and Rhizopus.

  12. Biocontrol Activity of the Local Strain of Metschnikowia pulcherrima on Different Postharvest Pathogens

    Directory of Open Access Journals (Sweden)

    Sezai Türkel

    2014-01-01

    Full Text Available The strains of the yeast Metschnikowia pulcherrima have strong biocontrol activity against various microorganisms. Biocontrol activity of M. pulcherrima largely depends on its iron immobilizing pigment pulcherrimin. Biocontrol activity of pulcherrimin producing strain, M. pulcherrima UMY15, isolated from local vineyards, was tested on different molds that cause food spoilage. M. pulcherrima UMY15 was a very effective biocontrol agent against Penicillium roqueforti, P. italicum, P. expansum, and Aspergillus oryzae in in-vitro plate tests. However, the inhibitory activity of M. pulcherrima UMY15 was less effective on Fusarium sp. and A. niger species in biocontrol assays. In addition, M. pulcherrima UMY15 strain completely inhibited the germination and mycelia growth of A. oryzae, A. parasiticus, and Fusarium sp. spores on artificial wounds of apples when they coinoculated with M. pulcherrima UMY15. Moreover, when coinoculated, M. pulcherrima UMY15 strain also inhibited the growth of P. roqueforti, P. italicum, P. expansum, A. oryzae, Fusarium sp., and Rhizopus sp. in grape juice, indicating that M. pulcherrima UMY15 can be used as a very effective biocontrol yeast against various species of postharvest pathogens, including   Penicillium, Aspergillus, Fusarium, and Rhizopus.

  13. A Preliminary Report on the Use of Bench-Top X-Ray Micro-Computerised Tomography to Study the Malpighian Tubules of the Overwintering Seven Spotted Ladybird Coccinella septempunctata L. (Coleoptera: Coccinellidae

    Directory of Open Access Journals (Sweden)

    Duncan Bell

    2012-01-01

    Full Text Available The application of micro-CT scanning techniques on a small sample of “Seven-spot ladybirds” Coccinella septempunctata, collected in December 2009, identified an accumulation of material with a very high, relative X-ray attenuation value in the malpighian tubules of most but not all of the individuals sampled. The passage of metals such as cadmium in soil through a food chain to finally accumulate in high concentrations in ladybirds and lacewings has been previously reported. The identification of the dense material found in our sample of ladybirds, its origin, and the process by which it accumulates in, and is processed by, the malpighian tubules is the challenge ahead. The authors speculate that a straightforward means of monitoring levels of metallic pollutants in the environment might emerge.

  14. Indirect effects of biocontrol of an invasive riparian plant (Tamarix) alters habitat and reduces herpetofauna abundance

    Science.gov (United States)

    Bateman, H.L.; Merritt, D.M.; Glenn, E.P.; Nagler, P.L.

    2014-01-01

    The biological control agent (tamarisk leaf beetle, Diorhabda spp.) is actively being used to defoliate exotic saltcedar or tamarisk (Tamarix spp.) in riparian ecosystems in western USA. The Virgin River in Arizona and Nevada is a system where tamarisk leaf beetle populations are spreading. Saltcedar biocontrol, like other control methods, has the potential to affect non-target species. Because amphibians and reptiles respond to vegetation changes in habitat and forage in areas where beetles are active, herpetofauna are model taxa to investigate potential impacts of biocontrol defoliation. Our objectives related herpetofauna abundance to vegetation cover and indices (normalized difference vegetation index, NDVI; enhanced vegetation index, EVI) and timing of biocontrol defoliation. We captured herpetofauna and ground-dwelling arthropods in trap arrays and measured vegetation using remotely sensed images and on-the-ground measurements at 16–21 sites 2 years before (2009–2010) and 2 years following (2011–2012) biocontrol defoliation. Following defoliation, riparian stands (including stands mixed with native and exotic trees and stands of monotypic exotic saltcedar) had significantly lower NDVI and EVI values and fewer captures of marked lizards. Total captures of herpetofauna (toads, lizards, and snakes) were related to higher vegetation cover and sites with a lower proportion of saltcedar. Our results suggest that effects of biocontrol defoliation are likely to be site-specific and depend upon the proportion of native riparian trees established prior to biocontrol introduction and defoliation. The mechanisms by which habitat structure, microclimate, and ultimately vertebrate species are affected by exotic plant biocontrol riparian areas should be a focus of natural-resource managers.

  15. The Potential of Streptomyces as Biocontrol Agents against the Rice Blast Fungus, Magnaporthe oryzae (Pyricularia oryzae)

    Science.gov (United States)

    Law, Jodi Woan-Fei; Ser, Hooi-Leng; Khan, Tahir M.; Chuah, Lay-Hong; Pusparajah, Priyia; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

    2017-01-01

    Rice is a staple food source for more than three billion people worldwide. However, rice is vulnerable to diseases, the most destructive among them being rice blast, which is caused by the fungus Magnaporthe oryzae (anamorph Pyricularia oryzae). This fungus attacks rice plants at all stages of development, causing annual losses of approximately 10–30% in various rice producing regions. Synthetic fungicides are often able to effectively control plant diseases, but some fungicides result in serious environmental and health problems. Therefore, there is growing interest in discovering and developing new, improved fungicides based on natural products as well as introducing alternative measures such as biocontrol agents to manage plant diseases. Streptomyces bacteria appear to be promising biocontrol agents against a wide range of phytopathogenic fungi, which is not surprising given their ability to produce various bioactive compounds. This review provides insight into the biocontrol potential of Streptomyces against the rice blast fungus, M. oryzae. The ability of various Streptomyces spp. to act as biocontrol agents of rice blast disease has been studied by researchers under both laboratory and greenhouse/growth chamber conditions. Laboratory studies have shown that Streptomyces exhibit inhibitory activity against M. oryzae. In greenhouse studies, infected rice seedlings treated with Streptomyces resulted in up to 88.3% disease reduction of rice blast. Studies clearly show that Streptomyces spp. have the potential to be used as highly effective biocontrol agents against rice blast disease; however, the efficacy of any biocontrol agent may be affected by several factors including environmental conditions and methods of application. In order to fully exploit their potential, further studies on the isolation, formulation and application methods of Streptomyces along with field experiments are required to establish them as effective biocontrol agents. PMID:28144236

  16. An In vitro Study of Bio-Control and Plant Growth Promotion Potential of Salicaceae Endophytes

    Science.gov (United States)

    Kandel, Shyam L.; Firrincieli, Andrea; Joubert, Pierre M.; Okubara, Patricia A.; Leston, Natalie D.; McGeorge, Kendra M.; Mugnozza, Giuseppe S.; Harfouche, Antoine; Kim, Soo-Hyung; Doty, Sharon L.

    2017-01-01

    Microbial communities in the endosphere of Salicaceae plants, poplar (Populus trichocarpa) and willow (Salix sitchensis), have been demonstrated to be important for plant growth promotion, protection from biotic and abiotic stresses, and degradation of toxic compounds. Our study aimed to investigate bio-control activities of Salicaceae endophytes against various soil borne plant pathogens including Rhizoctonia solani AG-8, Fusarium culmorum, Gaeumannomyces graminis var. tritici, and Pythium ultimum. Additionally, different plant growth promoting traits such as biological nitrogen fixation (BNF), indole-3-acetic acid (IAA) biosynthesis, phosphate solubilization, and siderophore production were assessed in all bio-control positive strains. Burkholderia, Rahnella, Pseudomonas, and Curtobacterium were major endophyte genera that showed bio-control activities in the in-vitro assays. The bio-control activities of Burkholderia strains were stronger across all tested plant pathogens as compared to other stains. Genomes of sequenced Burkholderia strains WP40 and WP42 were surveyed to identify the putative genes involved in the bio-control activities. The ocf and hcnABC gene clusters responsible for biosynthesis of the anti-fungal metabolites, occidiofungin and hydrogen cyanide, are present in the genomes of WP40 and WP42. Nearly all endophyte strains showing the bio-control activities produced IAA, solubilized tricalcium phosphate, and synthesized siderophores in the culture medium. Moreover, some strains reduced acetylene into ethylene in the acetylene reduction assay, a common assay used for BNF. Salicaceae endophytes could be useful for bio-control of various plant pathogens, and plant growth promotion possibly through the mechanisms of BNF, IAA production, and nutrient acquisition.

  17. Heart tissue of harlequin (hq)/Big Blue mice has elevated reactive oxygen species without significant impact on the frequency and nature of point mutations in nuclear DNA

    Energy Technology Data Exchange (ETDEWEB)

    Crabbe, Rory A. [Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7 (Canada); Hill, Kathleen A., E-mail: khill22@uwo.ca [Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7 (Canada)

    2010-09-10

    Age is a major risk factor for heart disease, and cardiac aging is characterized by elevated mitochondrial reactive oxygen species (ROS) with compromised mitochondrial and nuclear DNA integrity. To assess links between increased ROS levels and mutations, we examined in situ levels of ROS and cII mutation frequency, pattern and spectrum in the heart of harlequin (hq)/Big Blue mice. The hq mouse is a model of premature aging with mitochondrial dysfunction and increased risk of oxidative stress-induced heart disease with the means for in vivo mutation detection. The hq mutation produces a significant downregulation in the X-linked apoptosis-inducing factor gene (Aif) impairing both the antioxidant and oxidative phosphorylation functions of AIF. Brain and skin of hq disease mice have elevated frequencies of point mutations in nuclear DNA and histopathology characterized by cell loss. Reports of associated elevations in ROS in brain and skin have mixed results. Herein, heart in situ ROS levels were elevated in hq disease compared to AIF-proficient mice (p < 0.0001) yet, mutation frequency and pattern were similar in hq disease, hq carrier and AIF-proficient mice. Heart cII mutations were also assessed 15 days following an acute exposure to an exogenous ROS inducer (10 mg paraquat/kg). Acute paraquat exposure with a short mutant manifestation period was insufficient to elevate mutation frequency or alter mutation pattern in the post-mitotic heart tissue of AIF-proficient mice. Paraquat induction of ROS requires mitochondrial complex I and thus is likely compromised in hq mice. Results of this preliminary survey and the context of recent literature suggest that determining causal links between AIF deficiency and the premature aging phenotypes of specific tissues is better addressed with assay of mitochondrial ROS and large-scale changes in mitochondrial DNA in specific cell types.

  18. Environmental factors affect the activity of biocontrol agents against ochratoxigenic Aspergillus carbonarius on wine grape.

    Science.gov (United States)

    De Curtis, F; de Felice, D V; Ianiri, G; De Cicco, V; Castoria, R

    2012-09-17

    The influence of temperature and relative humidity (RH) on the activity of three biocontrol agents-the yeast Metschnikowia pulcherrima LS16 and two strains of the yeast-like fungus Aureobasidium pullulans LS30 and AU34-2-against infection by A. carbonarius and ochratoxin A (OTA) accumulation in wine grape berries was investigated in lab-scale experiments. The presence of wounds on grape skin dramatically favored infection of berries by A. carbonarius strain A1102, since unwounded berries showed very low levels of infection at all conditions of RH and temperature tested. Artificially wounded berries pre-treated with the biocontrol agents were inoculated with the ochratoxigenic A. carbonarius strain A1102 and were incubated for 5 days at two levels of RH (60% and 100%) and three different temperatures (20, 25 and 30 °C). The three biocontrol agents were able to prevent infections at 60% RH and 20 °C. At 60% RH and 25 °C only strain AU34-2 achieved some protection on day 5, whereas at 30 °C a limited biocontrol efficacy was evident only up to day 2. At 100% RH, LS16, LS30 and AU34-2 showed effective protection of grape berries at 20 °C until the 5th day of incubation. The three biocontrol agents achieved significant protection at higher temperatures only until the 2nd day after the beginning of the experiment: all three strains at 25 °C, and only strain LS16 at 30 °C. After 5 days, the three biocontrol agents were able to significantly reduce the level of OTA in berries at all the conditions tested. This occurred even when protection from infection was not significant, except at 30 °C and 100% of RH for all the three strains, and at 25 °C and 100% of RH for strain LS16. The biocontrol agents displayed a higher rate of colonization on grape berries at 20 and 25 °C than at 30 °C. The higher value of RH (100%) appeared to increase the rate of colonization, in particular at 20 and 25 °C. Taken together, our results emphasize the significant influence of

  19. Biocontrol of Phytophthora Blight and Anthracnose in Pepper by Sequentially Selected Antagonistic Rhizobacteria against Phytophthora capsici

    Directory of Open Access Journals (Sweden)

    Mee Kyung Sang

    2013-06-01

    Full Text Available We previously developed a sequential screening procedure to select antagonistic bacterial strains against Phytophthora capsici in pepper plants. In this study, we used a modified screening procedure to select effective biocontrol strains against P. capsici; we evaluated the effect of selected strains on Phytophthora blight and anthracnose occurrence and fruit yield in pepper plants under field and plastic house conditions from 2007 to 2009. We selected four potential biocontrol strains (Pseudomonas otitidis YJR27, P. putida YJR92, Tsukamurella tyrosinosolvens YJR102, and Novosphingobium capsulatum YJR107 among 239 bacterial strains. In the 3-year field tests, all the selected strains significantly (P < 0.05 reduced Phytophthora blight without influencing rhizosphere microbial populations; they showed similar or better levels of disease suppressions than in metalaxyl treatment in the 2007 and 2009 tests, but not in the 2008 test. In the 2-year plastic house tests, all the selected strains significantly (P < 0.05 reduced anthracnose incidence in at least one of the test years, but their biocontrol activities were variable. In addition, strains YJR27, YJR92, and YJR102, in certain harvests, increased pepper fruit numbers in field tests and red fruit weights in plastic house tests. Taken together, these results indicate that the screening procedure is rapid and reliable for the selection of potential biocontrol strains against P. capsici in pepper plants. In addition, these selected strains exhibited biocontrol activities against anthracnose, and some of the strains showed plant growth-promotion activities on pepper fruit.

  20. Impact of a Recombinant Biocontrol Bacterium, Pseudomonas fluorescens pc78, on Microbial Community in Tomato Rhizosphere

    Directory of Open Access Journals (Sweden)

    Hyun Gi Kong

    2016-04-01

    Full Text Available Pseudomonas fluorescens pc78 is an effective biocontrol agent for soil-borne fungal diseases. We previously constructed a P43-gfp tagged biocontrol bacteria P. fluorescens pc78-48 to investigate bacterial traits in natural ecosystem and the environmental risk of genetically modified biocontrol bacteria in tomato rhizosphere. Fluctuation of culturable bacteria profile, microbial community structure, and potential horizontal gene transfer was investigated over time after the bacteria treatment to the tomato rhizosphere. Tagged gene transfer to other organisms such as tomato plants and bacteria cultured on various media was examined by polymerase chain reaction, using gene specific primers. Transfer of chromosomally integrated P43-gfp from pc78 to other organisms was not apparent. Population and colony types of culturable bacteria were not significantly affected by the introduction of P. fluorescens pc78 or pc78-48 into tomato rhizosphere. Additionally, terminal restriction fragment length polymorphism profiles were investigated to estimate the influence on the microbial community structure in tomato rhizosphere between non-treated and pc78-48-treated samples. Interestingly, rhizosphere soil treated with strain pc78-48 exhibited a significantly different bacterial community structure compared to that of non-treated rhizosphere soil. Our results suggest that biocontrol bacteria treatment influences microbial community in tomato rhizosphere, while the chromosomally modified biocontrol bacteria may not pose any specific environmental risk in terms of gene transfer.

  1. Biocontrol of the Potato Blackleg and Soft Rot Diseases Caused by Dickeya dianthicola.

    Science.gov (United States)

    Raoul des Essarts, Yannick; Cigna, Jérémy; Quêtu-Laurent, Angélique; Caron, Aline; Munier, Euphrasie; Beury-Cirou, Amélie; Hélias, Valérie; Faure, Denis

    2015-10-23

    Development of protection tools targeting Dickeya species is an important issue in the potato production. Here, we present the identification and the characterization of novel biocontrol agents. Successive screenings of 10,000 bacterial isolates led us to retain 58 strains that exhibited growth inhibition properties against several Dickeya sp. and/or Pectobacterium sp. pathogens. Most of them belonged to the Pseudomonas and Bacillus genera. In vitro assays revealed a fitness decrease of the tested Dickeya sp. and Pectobacterium sp. pathogens in the presence of the biocontrol agents. In addition, four independent greenhouse assays performed to evaluate the biocontrol bacteria effect on potato plants artificially contaminated with Dickeya dianthicola revealed that a mix of three biocontrol agents, namely, Pseudomonas putida PA14H7 and Pseudomonas fluorescens PA3G8 and PA4C2, repeatedly decreased the severity of blackleg symptoms as well as the transmission of D. dianthicola to the tuber progeny. This work highlights the use of a combination of biocontrol strains as a potential strategy to limit the soft rot and blackleg diseases caused by D. dianthicola on potato plants and tubers.

  2. Biocontrol of Phytophthora Blight and Anthracnose in Pepper by Sequentially Selected Antagonistic Rhizobacteria against Phytophthora capsici.

    Science.gov (United States)

    Sang, Mee Kyung; Shrestha, Anupama; Kim, Du-Yeon; Park, Kyungseok; Pak, Chun Ho; Kim, Ki Deok

    2013-06-01

    We previously developed a sequential screening procedure to select antagonistic bacterial strains against Phytophthora capsici in pepper plants. In this study, we used a modified screening procedure to select effective biocontrol strains against P. capsici; we evaluated the effect of selected strains on Phytophthora blight and anthracnose occurrence and fruit yield in pepper plants under field and plastic house conditions from 2007 to 2009. We selected four potential biocontrol strains (Pseudomonas otitidis YJR27, P. putida YJR92, Tsukamurella tyrosinosolvens YJR102, and Novosphingobium capsulatum YJR107) among 239 bacterial strains. In the 3-year field tests, all the selected strains significantly (P biocontrol activities were variable. In addition, strains YJR27, YJR92, and YJR102, in certain harvests, increased pepper fruit numbers in field tests and red fruit weights in plastic house tests. Taken together, these results indicate that the screening procedure is rapid and reliable for the selection of potential biocontrol strains against P. capsici in pepper plants. In addition, these selected strains exhibited biocontrol activities against anthracnose, and some of the strains showed plant growth-promotion activities on pepper fruit.

  3. Surfactin triggers biofilm formation of Bacillus subtilis in melon phylloplane and contributes to the biocontrol activity.

    Science.gov (United States)

    Zeriouh, Houda; de Vicente, Antonio; Pérez-García, Alejandro; Romero, Diego

    2014-07-01

    The biocontrol activity of many Bacillus species has been traditionally related to the direct antagonism of pathogens. In previous works, we reported that B. subtilis strain UMAF6614 was an efficient biocontrol agent that produced bacillomycin, fengycin and surfactin lipopeptides. Bacillomycins and fengycins were shown to have antagonistic activity towards fungal and bacterial pathogens of cucurbits; however, the functionality of surfactin remained unclear. In this study, the role of surfactin in the biocontrol activity of this strain was investigated. We observed that a deficiency in surfactin production led to a partial reduction of disease suppression by this biocontrol agent, which coincided with a defect in biofilm formation and the colonization of the melon phylloplane. These effects were due to a dramatic reduction in the production of exopolysaccharide and the TasA protein, which are the two major components of the extracellular matrix. We propose that the biocontrol activity of this strain is the result of the coordinated action of the three families of lipopeptides. B. subtilis UMAF6614 produces surfactin to trigger biofilm formation on melon phylloplane, which ensures the long-term persistence and the adequate secretion of suppressive lipopeptides, bacillomycins and fengycins, which efficiently target pathogens.

  4. Impact of a Recombinant Biocontrol Bacterium, Pseudomonas fluorescens pc78, on Microbial Community in Tomato Rhizosphere.

    Science.gov (United States)

    Kong, Hyun Gi; Kim, Nam Hee; Lee, Seung Yeup; Lee, Seon-Woo

    2016-04-01

    Pseudomonas fluorescens pc78 is an effective biocontrol agent for soil-borne fungal diseases. We previously constructed a P43-gfp tagged biocontrol bacteria P. fluorescens pc78-48 to investigate bacterial traits in natural ecosystem and the environmental risk of genetically modified biocontrol bacteria in tomato rhizosphere. Fluctuation of culturable bacteria profile, microbial community structure, and potential horizontal gene transfer was investigated over time after the bacteria treatment to the tomato rhizosphere. Tagged gene transfer to other organisms such as tomato plants and bacteria cultured on various media was examined by polymerase chain reaction, using gene specific primers. Transfer of chromosomally integrated P43-gfp from pc78 to other organisms was not apparent. Population and colony types of culturable bacteria were not significantly affected by the introduction of P. fluorescens pc78 or pc78-48 into tomato rhizosphere. Additionally, terminal restriction fragment length polymorphism profiles were investigated to estimate the influence on the microbial community structure in tomato rhizosphere between non-treated and pc78-48-treated samples. Interestingly, rhizosphere soil treated with strain pc78-48 exhibited a significantly different bacterial community structure compared to that of non-treated rhizosphere soil. Our results suggest that biocontrol bacteria treatment influences microbial community in tomato rhizosphere, while the chromosomally modified biocontrol bacteria may not pose any specific environmental risk in terms of gene transfer.

  5. Attachment capability of antagonistic yeast Rhodotorula glutinis to Botrytis cinerea contributes to biocontrol efficacy

    Directory of Open Access Journals (Sweden)

    Boqiang eLi

    2016-05-01

    Full Text Available Rhodotorula glutinis as an antagonism show good biocontrol performance against various postharvest diseases in fruits. In the present study, strong attachment capability of R. glutinis to spores and hyphae of Botrytis cinerea was observed. Further analysis showed that certain protein components on the yeast cell surface played critical role during the interaction between R. glutinis and B. cinerea. The components mainly distributed at the poles of yeast cells and might contain glycosylation modification, as tunicamycin treated yeast cells lost attachment capability to B. cinerea. To investigate contributions of attachment capability of R. glutinis to its biocontrol efficacy, yeast cells were mutagenized with 3% methane-sulfonic acid ethyl ester (EMS, and a mutant CE4 with stable non-attaching phenotype was obtained. No significant difference was found on colony, cell morphology, reproductive ability and capsule formation between the mutant and wild type. However, there was a distinct difference in India ink positive staining patterns between the two strains. Moreover, wild type strain of R. glutinis showed better performance on inhibiting spore germination and mycelial growth of B. cinerea than CE4 strain when yeast cells and B. cinerea were co-cultured in vitro. In biocontrol assay, both wild type and CE4 strains showed significant biocontrol efficacy against gray mould caused by B. cinerea in apple fruit, whereas, control effect of CE4 strain was lower than that of wild type. Our findings provided new evidences that attachment capability of R. glutinis to B. cinerea contributed to its biocontrol efficacy.

  6. Ochratoxin A Management in Vineyards by Lobesia botrana Biocontrol

    Directory of Open Access Journals (Sweden)

    Giuseppe Cozzi

    2013-01-01

    Full Text Available Grape berries attacked by Lobesia botrana larvae are more easily infected by Aspergillus section Nigri (black aspergilli ochratoxigenic species. Two-year field trials were carried out in Apulia (Italy to evaluate a bioinsecticide control strategy against L. botrana and the indirect effect on reducing ochratoxin A (OTA contamination in vineyards. A commercial Bacillus thuringiensis formulate and an experimental Beauveria bassiana (ITEM-1559 formulate were tested in two vineyards cultivated with the same grape variety, Negroamaro, but with two different training systems (espalier and little-arbor techniques. In both years and training systems the treatments by B. bassiana ITEM-1559 significantly controlled L. botrana larvae attacks with effectiveness similar to B. thuringensis (more than 20%. A significant reduction of OTA concentrations (up to 80% compared to untreated controls was observed only in the first year in both training systems, when the metereological parameters prior to harvest were more favorable to the insect attack. Results of field trials showed that B. bassiana ITEM-1559 is a valid bioinsecticide against L. botrana and that grape moth biocontrol is a strategy to reduce OTA contamination in vineyard in seasons with heavy natural infestation.

  7. Ochratoxin A management in vineyards by Lobesia botrana biocontrol.

    Science.gov (United States)

    Cozzi, Giuseppe; Somma, Stefania; Haidukowski, Miriam; Logrieco, Antonio F

    2013-01-02

    Grape berries attacked by Lobesia botrana larvae are more easily infected by Aspergillus section Nigri (black aspergilli) ochratoxigenic species. Two-year field trials were carried out in Apulia (Italy) to evaluate a bioinsecticide control strategy against L. botrana and the indirect effect on reducing ochratoxin A (OTA) contamination in vineyards. A commercial Bacillus thuringiensis formulate and an experimental Beauveria bassiana (ITEM-1559) formulate were tested in two vineyards cultivated with the same grape variety, Negroamaro, but with two different training systems (espalier and little-arbor techniques). In both years and training systems the treatments by B. bassiana ITEM-1559 significantly controlled L. botrana larvae attacks with effectiveness similar to B. thuringensis (more than 20%). A significant reduction of OTA concentrations (up to 80% compared to untreated controls) was observed only in the first year in both training systems, when the metereological parameters prior to harvest were more favorable to the insect attack. Results of field trials showed that B. bassiana ITEM-1559 is a valid bioinsecticide against L. botrana and that grape moth biocontrol is a strategy to reduce OTA contamination in vineyard in seasons with heavy natural infestation.

  8. Rhizobia: a potential biocontrol agent for soilborne fungal pathogens.

    Science.gov (United States)

    Das, Krishnashis; Prasanna, Radha; Saxena, Anil Kumar

    2017-03-12

    Rhizobia are a group of organisms that are well known for their ability to colonize root surfaces and form symbiotic associations with legume plants. They not only play a major role in biological nitrogen fixation but also improve plant growth and reduce disease incidence in various crops. Rhizobia are known to control the growth of many soilborne plant pathogenic fungi belonging to different genera like Fusarium, Rhizoctonia, Sclerotium, and Macrophomina. Antagonistic activity of rhizobia is mainly attributed to production of antibiotics, hydrocyanic acid (HCN), mycolytic enzymes, and siderophore under iron limiting conditions. Rhizobia are also reported to induce systemic resistance and enhance expression of plant defense-related genes, which effectively immunize the plants against pathogens. Seed bacterization with appropriate rhizobial strain leads to elicitation and accumulation of phenolic compounds, isoflavonoid phytoalexins, and activation of enzymes like L-phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), peroxidase (POX), polyphenol oxidase (PPO), and others involved in phenylpropanoid and isoflavonoid pathways. Development of Rhizobium inoculants with dual attributes of nitrogen fixation and antagonism against phytopathogens can contribute to increased plant growth and productivity. This compilation aims to bring together the available information on the biocontrol facet of rhizobia and identify research gaps and effective strategies for future research in this area.

  9. Cost modeling of pseudomonoas fluorescens and pseudomonoas chlororphis biocontrol for competitive exclusion of salmonella enterica on tomatoes

    Science.gov (United States)

    Biocontrol measures may enhance postharvest interventions, however; published research on process-based models for biocontrol of foodborne pathogens on produce is limited. The aim of this research was to develop cost model estimates for competitive exclusion process using Pseudomonas fluorescens and...

  10. Evaluation of recycled bioplastic pellets and a sprayable formulation for application of an Aspergillus flavus biocontrol strain

    Science.gov (United States)

    Biocontrol of Aspergillus flavus using inoculated bioplastic granules has been proven to be effective under laboratory and field conditions. In the present study, the use of low-density pellets from recycled bioplastic as a biocontrol strain carrier was evaluated. Applying recycled bioplastic pell...

  11. Utilization of winery wastes for Trichoderma viride biocontrol agent production by solid state fermentation

    Institute of Scientific and Technical Information of China (English)

    BAI Zhihui; JIN Bo; LI Yuejie; CHEN Jian; LI Zuming

    2008-01-01

    Biocontrol agents are safe and environmental friendly alternatives for pesticides in agriculture application.Trichoderma v/ride WEBL0703 performed a high level of antagonistic activity toward a broad spectrum of phytopathogens and was determined as a biocontrol agent,which was produced by solid state fermentation using grape marc and wine lees.The maximum yield of T.viride conidia was up to 6.65×109 CFU/g initial dry substrate (IDS) after 10 d fermentation.As important enzymes for protecting plants from disease,ehitinase,β-glucanase,and pectinase yields were 47.8 U/g IDS,8.32 U/g IDS and 9.83 U/g IDS,respectively.These results show that it is feasible to convert winery wastes to a value-added and environmental friendly biocontrol agent.

  12. Potencialidade antagonística detectada em alguns procariotas agentes de biocontrole de enfermidades de plantas

    OpenAIRE

    Barra,Victor Rafael; SILVA, Reginaldo da; Ferraz,Hélio Glelson Maciel; Macagnan,Dirceu; Silva, Harllen Sandro Alves; Moura,Andréa Bittencourt; Halfeld-Vieira,Bernardo de Almeida; Mendonça, Henrique Lopes de; Vieira Júnior,José Roberto

    2008-01-01

    Ao longo de vários anos, no Laboratório de Bacteriologia de Plantas e Controle Biológico (LBPCB) do Departamento de Fitopatologia da Universidade Federal de Viçosa têm-se, sistematicamente, isolado, de rizosfera, rizoplano e filoplano de plantas cultivadas de importância econômica, milhares de procariotas os quais são testados, um a um, como agentes de biocontrole de enfermidades. A grande maioria deles, como esperado, não exibe qualquer potencialidade como agente de biocontrole e é descartad...

  13. Whole genome shotgun sequence of Bacillus amyloliquefaciens TF28, a biocontrol entophytic bacterium.

    Science.gov (United States)

    Zhang, Shumei; Jiang, Wei; Li, Jing; Meng, Liqiang; Cao, Xu; Hu, Jihua; Liu, Yushuai; Chen, Jingyu; Sha, Changqing

    2016-01-01

    Bacillus amyloliquefaciens TF28 is a biocontrol endophytic bacterium that is capable of inhibition of a broad range of plant pathogenic fungi. The strain has the potential to be developed into a biocontrol agent for use in agriculture. Here we report the whole-genome shotgun sequence of the strain. The genome size of B. amyloliquefaciens TF28 is 3,987,635 bp which consists of 3754 protein-coding genes, 65 tandem repeat sequences, 47 minisatellite DNA, 2 microsatellite DNA, 63 tRNA, 7rRNA, 6 sRNA, 3 prophage and CRISPR domains.

  14. Bio-Control of Salmonella Enteritidis in Foods Using Bacteriophages.

    Science.gov (United States)

    Bao, Hongduo; Zhang, Pengyu; Zhang, Hui; Zhou, Yan; Zhang, Lili; Wang, Ran

    2015-08-24

    Two lytic phages, vB_SenM-PA13076 (PA13076) and vB_SenM-PC2184 (PC2184), were isolated from chicken sewage and characterized with host strains Salmonella Enteritidis (SE) ATCC13076 and CVCC2184, respectively. Transmission electron microscopy revealed that they belonged to the family Myoviridae. The lytic abilities of these two phages in liquid culture showed 104 multiplicity of infection (MOI) was the best in inhibiting bacteria, with PC2184 exhibiting more activity than PA13076. The two phages exhibited broad host range within the genus Salmonella. Phage PA13076 and PC2184 had a lytic effect on 222 (71.4%) and 298 (95.8%) of the 311 epidemic Salmonella isolates, respectively. We tested the effectiveness of phage PA13076 and PC2184 as well as a cocktail combination of both in three different foods (chicken breast, pasteurized whole milk and Chinese cabbage) contaminated with SE. Samples were spiked with 1 × 10(4) CFU individual SE or a mixture of strains (ATCC13076 and CVCC2184), then treated with 1 × 10(8) PFU individual phage or a two phage cocktail, and incubated at 4 °C or 25 °C for 5 h. In general, the inhibitory effect of phage and phage cocktail was better at 4 °C than that at 25 °C, whereas the opposite result was observed in Chinese cabbage, and phage cocktail was better than either single phage. A significant reduction in bacterial numbers (1.5-4 log CFU/sample, p < 0.05) was observed in all tested foods. The two phages on the three food samples were relatively stable, especially at 4 ºC, with the phages exhibiting the greatest stability in milk. Our research shows that our phages have potential effectiveness as a bio-control agent of Salmonella in foods.

  15. Bio-Control of Salmonella Enteritidis in Foods Using Bacteriophages

    Directory of Open Access Journals (Sweden)

    Hongduo Bao

    2015-08-01

    Full Text Available Two lytic phages, vB_SenM-PA13076 (PA13076 and vB_SenM-PC2184 (PC2184, were isolated from chicken sewage and characterized with host strains Salmonella Enteritidis (SE ATCC13076 and CVCC2184, respectively. Transmission electron microscopy revealed that they belonged to the family Myoviridae. The lytic abilities of these two phages in liquid culture showed 104 multiplicity of infection (MOI was the best in inhibiting bacteria, with PC2184 exhibiting more activity than PA13076. The two phages exhibited broad host range within the genus Salmonella. Phage PA13076 and PC2184 had a lytic effect on 222 (71.4% and 298 (95.8% of the 311 epidemic Salmonella isolates, respectively. We tested the effectiveness of phage PA13076 and PC2184 as well as a cocktail combination of both in three different foods (chicken breast, pasteurized whole milk and Chinese cabbage contaminated with SE. Samples were spiked with 1 × 104 CFU individual SE or a mixture of strains (ATCC13076 and CVCC2184, then treated with 1 × 108 PFU individual phage or a two phage cocktail, and incubated at 4 °C or 25 °C for 5 h. In general, the inhibitory effect of phage and phage cocktail was better at 4 °C than that at 25 °C, whereas the opposite result was observed in Chinese cabbage, and phage cocktail was better than either single phage. A significant reduction in bacterial numbers (1.5–4 log CFU/sample, p < 0.05 was observed in all tested foods. The two phages on the three food samples were relatively stable, especially at 4 ºC, with the phages exhibiting the greatest stability in milk. Our research shows that our phages have potential effectiveness as a bio-control agent of Salmonella in foods.

  16. Bio-Control of Salmonella Enteritidis in Foods Using Bacteriophages

    Science.gov (United States)

    Bao, Hongduo; Zhang, Pengyu; Zhang, Hui; Zhou, Yan; Zhang, Lili; Wang, Ran

    2015-01-01

    Two lytic phages, vB_SenM-PA13076 (PA13076) and vB_SenM-PC2184 (PC2184), were isolated from chicken sewage and characterized with host strains Salmonella Enteritidis (SE) ATCC13076 and CVCC2184, respectively. Transmission electron microscopy revealed that they belonged to the family Myoviridae. The lytic abilities of these two phages in liquid culture showed 104 multiplicity of infection (MOI) was the best in inhibiting bacteria, with PC2184 exhibiting more activity than PA13076. The two phages exhibited broad host range within the genus Salmonella. Phage PA13076 and PC2184 had a lytic effect on 222 (71.4%) and 298 (95.8%) of the 311 epidemic Salmonella isolates, respectively. We tested the effectiveness of phage PA13076 and PC2184 as well as a cocktail combination of both in three different foods (chicken breast, pasteurized whole milk and Chinese cabbage) contaminated with SE. Samples were spiked with 1 × 104 CFU individual SE or a mixture of strains (ATCC13076 and CVCC2184), then treated with 1 × 108 PFU individual phage or a two phage cocktail, and incubated at 4 °C or 25 °C for 5 h. In general, the inhibitory effect of phage and phage cocktail was better at 4 °C than that at 25 °C, whereas the opposite result was observed in Chinese cabbage, and phage cocktail was better than either single phage. A significant reduction in bacterial numbers (1.5–4 log CFU/sample, p < 0.05) was observed in all tested foods. The two phages on the three food samples were relatively stable, especially at 4 °C, with the phages exhibiting the greatest stability in milk. Our research shows that our phages have potential effectiveness as a bio-control agent of Salmonella in foods. PMID:26305252

  17. Biosynthetic mechanism for sunscreens of the biocontrol agent Lysobacter enzymogenes.

    Directory of Open Access Journals (Sweden)

    Yan Wang

    Full Text Available Lysobacter are ubiquitous environmental bacteria emerging as novel biocontrol agents and new sources of anti-infectives. So far, very little effort has been invested in the study of the biology of these Gram-negative gliding bacteria. Many Lysobacter species are characterized by their yellow-orange appearance. Using transposon mutagenesis, we identified a stand-alone polyketide synthase (PKS gene cluster required for the pigment production in L. enzymogenes OH11. The yellow pigments were abolished in the "white" mutants generated by target-specific deletions of ketosynthase (KS, acyl carrier protein, or ketoreductase. Spectroscopic data suggested that the pigments belong to xanthomonadin-like aryl polyenes. Polyene-type polyketides are known to be biosynthesized by modular PKS (Type I, not by stand-alone PKS (Type II which always contain the heterodimer KS-CLF (chain-length factor as the key catalytic component. Remarkably, this aryl polyene PKS complex only contains the KS (ORF17, but not the CLF. Instead, a hypothetical protein (ORF16 is located immediately next to ORF17. ORF16-17 homologs are widespread in numerous uncharacterized microbial genomes, in which an ORF17 homolog is always accompanied by an ORF16 homolog. The deletion of ORF16 eliminated pigment production, and homology modeling suggested that ORF16 shares a structural similarity to the N-terminal half of CLF. A point-mutation of glutamine (Q166A that is the conserved active site of known CLF abolished pigment production. The "white" mutants are significantly more sensitive to UV/visible light radiation or H2O2 treatment than the wild type. These results unveil the first example of Type II PKS-synthesized polyene pigments and show that the metabolites serve as Lysobacter "sunscreens" that are important for the survival of these ubiquitous environmental organisms.

  18. Tick control: trapping, biocontrol, host management and other alternative strategies

    Science.gov (United States)

    Ginsberg, Howard S.; Edited by Sonenshine, Daniel E.; Roe, R. Michael

    2014-01-01

    Biology of Ticks is the most comprehensive work on tick biology and tick-borne diseases. This second edition is a multi-authored work, featuring the research and analyses of renowned experts across the globe. Spanning two volumes, the book examines the systematics, biology, structure, ecological adaptations, evolution, genomics and the molecular processes that underpin the growth, development and survival of these important disease-transmitting parasites. Also discussed is the remarkable array of diseases transmitted (or caused) by ticks, as well as modern methods for their control. This book should serve as a modern reference for students, scientists, physicians, veterinarians and other specialists. Volume I covers the biology of the tick and features chapters on tick systematics, tick life cycles, external and internal anatomy, and others dedicated to specific organ systems, specifically, the tick integument, mouthparts and digestive system, salivary glands, waste removal, salivary glands, respiratory system, circulatory system and hemolymph, fat body, the nervous and sensory systems and reproductive systems. Volume II includes chapters on the ecology of non-nidicolous and nidicolous ticks, genetics and genomics (including the genome of the Lyme disease vector Ixodes scapularis) and immunity, including host immune responses to tick feeding and tick-host interactions, as well as the tick's innate immune system that prevents and/or controls microbial infections. Six chapters cover in depth the many diseases caused by the major tick-borne pathogens, including tick-borne protozoa, viruses, rickettsiae of all types, other types of bacteria (e.g., the Lyme disease agent) and diseases related to tick paralytic agents and toxins. The remaining chapters are devoted to tick control using vaccines, acaricides, repellents, biocontrol, and, finally, techniques for breeding ticks in order to develop tick colonies for scientific study.

  19. Microencapsulation Technique with Organic Additives for Biocontrol Agents

    Directory of Open Access Journals (Sweden)

    Szczech Magdalena

    2016-06-01

    Full Text Available The aim of these studies was to develop an effective formulation for microbial strains active in plant protection. Emulsification technique in oil was used to produce alginate microcapsules supplemented with organic additives to improve production process and stability of the preparations during storage. The release of microorganisms from the capsules in soil and their effectiveness in biocontrol of Fusarium wilt were evaluated. Three bacterial strains Burkholderia cepacia strain CAT5, Bacillus spp. strains PZ9 and SZ61, and fungus Trichoderma virens TRS106 were immobilized separately in calcium alginate supplemented with chitosan, peat powder, or skim milk. The productivity of microcapsules was enhanced by 60% when peat was added to the alginate matrix. Peat reduced also contamination of the capsules during storage, significantly enhancing their quality. By contrast, the addition of skim milk reduced quality of the microcapsules. The additives did not influence the viability of entrapped microorganisms and their release in soil. The survival of the microbial cells was mainly related to the kind of microorganism used, and the highest viability showed Bacillus sp. PZ9 and Trichoderma TRS106. Lyophilization of the microcapsules appeared to be unfavorable by reducing microbial viability in the capsules and in the soil after application. The best properties: good storage ability and sufficient microbial release in the soil, exhibited wet microcapsules amended with peat. These capsules were used to control Fusarium wilt in tomato plants. The protective effect was obtained when the microcapsule-entrapped bacteria PZ9 were used. The effectiveness of this bacterium was comparable with fungicide. Peat-amended microcapsules entrapping Bacillus PZ9 showed the best quality and may have potential for commercial use.

  20. Knockout of a transgene by transcription activator-like effector nucleases (TALENs) in the sawfly, Athalia rosae (Hymenoptera) and the ladybird beetle, Harmonia axyridis (Coleoptera).

    Science.gov (United States)

    Hatakeyama, M; Yatomi, J; Sumitani, M; Takasu, Y; Sekiné, K; Niimi, T; Sezutsu, H

    2016-02-01

    Transcription activator-like effector nucleases (TALENs) are efficient tools for targeted genome editing and have been utilized in a number of insects. Here, we demonstrate the gene disruption (knockout) caused by TALENs targeting a transgene, 3xP3-driven enhanced green fluorescence protein (EGFP), that is integrated in the genome of two species, the sawfly Athalia rosae (Hymenoptera) and the ladybird beetle Harmonia axyridis (Coleoptera). Messenger RNAs of TALENs targeting the sequences adjacent to the chromophore region were microinjected into the eggs/embryos of each species. In At. rosae, when microinjection was performed at the posterior end of eggs, 15% of G(0) individuals showed a somatic mosaic phenotype for eye EGFP fluorescence. Three-quarters of the somatic mosaics produced EGFP-negative G(1) progeny. When eggs were injected at the anterior end, 63% of the G(0) individuals showed somatic mosaicism, and 17% of them produced EGFP-negative G(1) progeny. In H. axyridis, 25% of posterior-injected and 8% of anterior-injected G(0) individuals produced EGFP-negative G(1) progeny. In both species, the EGFP-negative progeny retained the EGFP gene, and various deletions were detected in the target sequences, indicating that gene disruption was successfully induced. Finally, for both species, 18-21% of G(0) founders produced gene knockout progeny sufficient for establishing knockout strains.

  1. Cytokinin production by Pseudomonas fluorescens G20-18 determines biocontrol activity against Pseudomonas syringae in Arabidopsis.

    Science.gov (United States)

    Großkinsky, Dominik K; Tafner, Richard; Moreno, María V; Stenglein, Sebastian A; García de Salamone, Inés E; Nelson, Louise M; Novák, Ondřej; Strnad, Miroslav; van der Graaff, Eric; Roitsch, Thomas

    2016-03-17

    Plant beneficial microbes mediate biocontrol of diseases by interfering with pathogens or via strengthening the host. Although phytohormones, including cytokinins, are known to regulate plant development and physiology as well as plant immunity, their production by microorganisms has not been considered as a biocontrol mechanism. Here we identify the ability of Pseudomonas fluorescens G20-18 to efficiently control P. syringae infection in Arabidopsis, allowing maintenance of tissue integrity and ultimately biomass yield. Microbial cytokinin production was identified as a key determinant for this biocontrol effect on the hemibiotrophic bacterial pathogen. While cytokinin-deficient loss-of-function mutants of G20-18 exhibit impaired biocontrol, functional complementation with cytokinin biosynthetic genes restores cytokinin-mediated biocontrol, which is correlated with differential cytokinin levels in planta. Arabidopsis mutant analyses revealed the necessity of functional plant cytokinin perception and salicylic acid-dependent defence signalling for this biocontrol mechanism. These results demonstrate microbial cytokinin production as a novel microbe-based, hormone-mediated concept of biocontrol. This mechanism provides a basis to potentially develop novel, integrated plant protection strategies combining promotion of growth, a favourable physiological status and activation of fine-tuned direct defence and abiotic stress resilience.

  2. Enhancement of Biocontrol Activities and Cyclic Lipopeptides Production by Chemical Mutagenesis of Bacillus subtilis XF-1, a Biocontrol Agent of Plasmodiophora brassicae and Fusarium solani.

    Science.gov (United States)

    Li, Xing-Yu; Yang, Jing-Jing; Mao, Zi-Chao; Ho, Hon-Hing; Wu, Yi-Xing; He, Yue-Qiu

    2014-12-01

    Bacillus subtilis XF-1 has been used as a biocontrol agent of clubroot disease of crucifers infected by Plasmodiophora brassicae, an obligate pathogen. In order to maximize the growth inhibition of the pathogen, random mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine was applied to strain XF-1. The efficacy of 226 selected mutants was assessed against the growth of an indicator fungal pathogen: Fusarium solani using agar plate assay and the disruptive effects on the resting spores of P. brassicae. Four mutants exhibited inhibition activity significantly higher than the wild type. The cell extracts of these mutants and the XF-1 were subjected to matrix-assisted laser desorption ionization-time of flight mass spectra analysis, and three families of cyclic lipopeptides (CLPs) fengycin, surfactin and iturin were identified from the parental strain and the screened mutants. However, the relative contents and compound diversity changed after mutagenesis, and there was slight variation in the surfactin and fengycin. Notably, only 5 iturin components were discovered from the wild strain XF-1, but 13 were obtained from the mutant strains, and the relative CLPs contents of all mutant strains increased substantially. The results suggested that CLPs might be one of main biocontrol mechanisms of the clubroot disease by XF-1. The 4 mutants are far more effective than the parental strain, and they would be promising biocontrol candidates not only against P. brassicae but probably other plant diseases caused by fungi.

  3. Pseudomonas fluorescens F113 mutant with enhanced competitive colonization ability and improved biocontrol activity against fungal root pathogens.

    Science.gov (United States)

    Barahona, Emma; Navazo, Ana; Martínez-Granero, Francisco; Zea-Bonilla, Teresa; Pérez-Jiménez, Rosa María; Martín, Marta; Rivilla, Rafael

    2011-08-01

    Motility is one of the most important traits for efficient rhizosphere colonization by Pseudomonas fluorescens F113rif (F113). In this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the Gac posttranscriptional system, the Wsp chemotaxis-like pathway, and the SadB pathway. Here we show that the kinB gene, which encodes a signal transduction protein that together with AlgB has been implicated in alginate production, participates in swimming motility repression through the Gac pathway, acting downstream of the GacAS two-component system. Gac mutants are impaired in secondary metabolite production and are unsuitable as biocontrol agents. However, the kinB mutant and a triple mutant affected in kinB, sadB, and wspR (KSW) possess a wild-type phenotype for secondary metabolism. The KSW strain is hypermotile and more competitive for rhizosphere colonization than the wild-type strain. We have compared the biocontrol activity of KSW with those of the wild-type strain and a phenotypic variant (F113v35 [V35]) which is hypermotile and hypercompetitive but is affected in secondary metabolism since it harbors a gacS mutation. Biocontrol experiments in the Fusarium oxysporum f. sp. radicis-lycopersici/Lycopersicum esculentum (tomato) and Phytophthora cactorum/Fragaria vesca (strawberry) pathosystems have shown that the three strains possess biocontrol activity. Biocontrol activity was consistently lower for V35, indicating that the production of secondary metabolites was the most important trait for biocontrol. Strain KSW showed improved biocontrol compared with the wild-type strain, indicating that an increase in competitive colonization ability resulted in improved biocontrol and that the rational design of biocontrol agents by mutation is feasible.

  4. Pseudomonas fluorescens F113 Mutant with Enhanced Competitive Colonization Ability and Improved Biocontrol Activity against Fungal Root Pathogens ▿

    Science.gov (United States)

    Barahona, Emma; Navazo, Ana; Martínez-Granero, Francisco; Zea-Bonilla, Teresa; Pérez-Jiménez, Rosa María; Martín, Marta; Rivilla, Rafael

    2011-01-01

    Motility is one of the most important traits for efficient rhizosphere colonization by Pseudomonas fluorescens F113rif (F113). In this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the Gac posttranscriptional system, the Wsp chemotaxis-like pathway, and the SadB pathway. Here we show that the kinB gene, which encodes a signal transduction protein that together with AlgB has been implicated in alginate production, participates in swimming motility repression through the Gac pathway, acting downstream of the GacAS two-component system. Gac mutants are impaired in secondary metabolite production and are unsuitable as biocontrol agents. However, the kinB mutant and a triple mutant affected in kinB, sadB, and wspR (KSW) possess a wild-type phenotype for secondary metabolism. The KSW strain is hypermotile and more competitive for rhizosphere colonization than the wild-type strain. We have compared the biocontrol activity of KSW with those of the wild-type strain and a phenotypic variant (F113v35 [V35]) which is hypermotile and hypercompetitive but is affected in secondary metabolism since it harbors a gacS mutation. Biocontrol experiments in the Fusarium oxysporum f. sp. radicis-lycopersici/Lycopersicum esculentum (tomato) and Phytophthora cactorum/Fragaria vesca (strawberry) pathosystems have shown that the three strains possess biocontrol activity. Biocontrol activity was consistently lower for V35, indicating that the production of secondary metabolites was the most important trait for biocontrol. Strain KSW showed improved biocontrol compared with the wild-type strain, indicating that an increase in competitive colonization ability resulted in improved biocontrol and that the rational design of biocontrol agents by mutation is feasible. PMID:21685161

  5. Fungal root endophytes of tomato from Kenya and their nematode biocontrol potential

    NARCIS (Netherlands)

    Bogner, C.W.; Kariuki, George M.; Elashry, A.; Sichtermann, Gisela; Buch, Ann-Katrin; Mishra, Bagdevi; Thines, M.; Grundler, F.M.W.; Schouten, A.

    2016-01-01

    The significance of fungal endophytes in African agriculture, particularly Kenya, has not been well investigated. Therefore, the objective of the present work was isolation, multi-gene phylogenetic characterization and biocontrol assessment of endophytic fungi harbored in tomato roots for nematode i

  6. Identification of Biocontrol Agents to Control the Fungal Pathogen, Geomyces destructans, in Bats

    Science.gov (United States)

    Braunstein, S.; Cheng, T.

    2013-12-01

    The fungal pathogen Geomyces destructans (Gd) causes the disease White-nose Syndrome (WNS) in bats and is estimated to have killed millions of bats since its emergence in North America in 2006. Gd is predicted to cause the local extinction of at least three bat species if rates of decline continue unabated. Given the devastating impacts of Gd to bat populations, identifying a viable method for controlling the pathogen is pertinent for conservation of affected bat species. Our work focuses on identifying naturally-occurring skin bacteria on bats that are antagonistic to Gd that could potentially be used as a biocontrol. We cultured bacteria from skin swabs taken from wild bats (Myotis lucifugus, Eptesicus fuscus, Myotis sodalis, Perimyotis subflavus). We conducted challenge experiments to identify bacterial strains that inhibited Gd growth. Bacteria that exhibited antifungal properties were identified using 16S and gyrB markers. Our methods identified several bacteria in the Pseudomonas fluorescens complex as potential biocontrol agents. Future work will continue to test the viability of these bacteria as biocontrol agents via experimental treatments with live captive bats. The failure of previous non-biocontrol methods highlights the importance of developing these bacteria as a biologically-friendly method for controlling Gd. A bat infected with Geomyces destructans. Photo by West Virginia Division of Natural Resources Bacterial culture from the swab of a bat's wings

  7. Yeast Biocontrol of a Fungal Plant Disease: A Model for Studying Organism Interrelationships

    Science.gov (United States)

    Chanchaichaovivat, Arun; Panijpan, Bhinyo; Ruenwongsa, Pintip

    2008-01-01

    An experiment on the action of the yeast, "Saccharomyces cerevisiae", against a fungal plant disease is proposed for secondary students (Grade 11) to support their study of organism interrelationship. This biocontrol experiment serves as the basis for discussing relationships among three organisms (red chilli fruit, "Saccharomyces cerevisiae," and…

  8. Agar composition affects in vitro screening of biocontrol activity of antagonistic microorganisms.

    Science.gov (United States)

    Bosmans, L; De Bruijn, I; De Mot, R; Rediers, H; Lievens, B

    2016-08-01

    Agar-based screening assays are the method of choice when evaluating antagonistic potential of bacterial biocontrol-candidates against pathogens. We showed that when using the same medium, but different agar compositions, the activity of a bacterial antagonist against Agrobacterium was strongly affected. Consequently, results from in vitro screenings should be interpreted cautiously.

  9. Isolation and identification of actinomycetes from a compost-amended soils biocontrol agents

    Energy Technology Data Exchange (ETDEWEB)

    Garcia de la Fuente, R.; Cuesta, G.; Fornes, F.; Abad, M.

    2009-07-01

    Compost capability to suppress soil-borne plant pathogens has become an interesting subject as a strategy for reducing the adverse effects of massive fungicides application in the environmental. In this context, actinomycetes have received considerable attention as biocontrol agents, particularly Streptomyces species. (Author)

  10. Stress tolerance and biocontrol performance of the yeast antagonist, Candida diversa, change with morphology transition.

    Science.gov (United States)

    Li, Guangkun; Chi, Mengshan; Chen, Huizhen; Sui, Yuan; Li, Yan; Liu, Yongsheng; Zhang, Xiaojing; Sun, Zhiqiang; Liu, Guoqing; Wang, Qi; Liu, Jia

    2016-02-01

    As an eco-friendly management method, biological control of postharvest diseases, utilizing antagonistic yeasts, is a research topic receiving considerable attention. Detailed knowledge on the biology of yeast antagonists is crucial when considering their potential application and development as biocontrol products. Changes in the growth form, such as single-cell to pseudohyphae, have been associated with the mode of action in postharvest biocontrol yeasts. In this study, the antagonistic yeast, Candida diversa, reversibly shifted from a single-cell morphology on yeast peptone dextrose (YPD) medium with 2 % agar to a pseudohyphal morphology on YPD with 0.3 % agar. The tolerance of the pseudohyphal form to heat and oxidative stresses, as well as the biocontrol efficacy against Botrytis cinerea on apple and kiwifruit stored at 25 and 4 °C, was significantly higher as compared to the single-cell form. This study provides new information on the ability of C. diversa to change its morphology and the impact of the morphology shift on stress tolerance and biocontrol performance.

  11. Biocontrol potential of endophytes harbored in Radula marginata (liverwort) from the New Zealand ecosystem.

    Science.gov (United States)

    Kusari, Parijat; Kusari, Souvik; Spiteller, Michael; Kayser, Oliver

    2014-10-01

    Radula marginata and Cannabis sativa L. are two phylogenetically unrelated plant species containing structurally similar secondary metabolites like cannabinoids. The major objective of our work was the isolation, identification, biocontrol efficacies, biofilm forming potential and anti-biofilm ability of endophytic microbial community of the liverwort R. marginata, as compared to bacterial endophytic isolates harbored in C. sativa plants. A total of 15 endophytic fungal and 4 endophytic bacterial isolates were identified, including the presence of a bacterial endosymbiont within an endophytic fungal isolate. The endosymbiont was visible only when the fungus containing it was challenged with two phytopathogens Botrytis cinerea and Trichothecium roseum, highlighting a tripartite microbe-microbe interaction and biocontrol potency of endophytes under biotic stress. We also observed sixteen types of endophytic fungal-pathogen and twelve types of endophytic bacterial-pathogen interactions coupled to varying degree of growth inhibitions of either the pathogen or endophyte or both. This showed the magnitude of biocontrol efficacies of endophytes in aiding plant fitness benefits under different media (environmental) conditions. Additionally, it was ecologically noteworthy to find the presence of similar endophytic bacterial genera in both Radula and Cannabis plants, which exhibited similar functional traits like biofilm formation and general anti-biofilm activities. Thus far, our work underlines the biocontrol potency and defensive functional traits (in terms of antagonism and biofilm formation) of endophytes harbored in liverwort R. marginata as compared to the endophytic community of phylogenetically unrelated but phytochemically similar plant C. sativa.

  12. Efficacy of water dispersible formulations of biocontrol strains of Aspergillus flavus for aflatoxin management in corn

    Science.gov (United States)

    Field experiments were conducted in 2011 and 2012 to evaluate the efficacy of water dispersible granule (WDG) formulations of biocontrol strains of Aspergillus flavus in controlling aflatoxin contamination of corn. In 2011, when aflatoxin was present at very high levels, no WDG treatment provided s...

  13. [Correction of autonomic reactions parameters in organism of cosmonaut with adaptive biocontrol method

    Science.gov (United States)

    Kornilova, L. N.; Cowings, P. S.; Toscano, W. B.; Arlashchenko, N. I.; Korneev, D. Iu; Ponomarenko, A. V.; Salagovich, S. V.; Sarantseva, A. V.; Kozlovskaia, I. B.

    2000-01-01

    Presented are results of testing the method of adaptive biocontrol during preflight training of cosmonauts. Within the MIR-25 crew, a high level of controllability of the autonomous reactions was characteristic of Flight Commanders MIR-23 and MIR-25 and flight Engineer MIR-23, while Flight Engineer MIR-25 displayed a weak intricate dependence of these reactions on the depth of relaxation or strain.

  14. Draft genome sequences of the Pseudomonas fluorescens biocontrol strains Wayne1R and Wood1R.

    Science.gov (United States)

    Rong, Xiaoqing; Gurel, Fulya Baysal; Meulia, Tea; McSpadden Gardener, Brian B

    2012-02-01

    Pseudomonas fluorescens strains Wayne1R and Wood1R have proven capacities to improve plant health. Here we report the draft genome sequences and automatic annotations of both strains. Genome comparisons reveal similarities with P. fluorescens strain Pf-5, reveal the novelty of Wood1R, and indicate some genes that may be related to biocontrol.

  15. Study on Attenuation Characteristics of Biocontrol Strain Anti-8098A, Bacillus cereus, against Ralstoniasolanacearum

    Institute of Scientific and Technical Information of China (English)

    BoLIU; Ying-ZhiLIN; Yu-JingZHU; Ci-BinGE; YiCAO

    2004-01-01

    The present study dealt with the attenuation characteristics of bacterial-wilt-disease biocontrol strain Anti-8098A, Bacillus cereus, againstpathogeny Ralstonia solanacearum (RS). In order to distinguish the pathogenicity of RS, the attenuation index (radius of the center red ring/radius of the whole mycelium ring, on TTC culture medium) was established (Hayward, 1976), companying with the mortality of tomato

  16. Heat shock improves stress tolerance and biocontrol performance of Rhodotorula mucilaginosa

    Science.gov (United States)

    Biological control of postharvest diseases, utilizing wild species and strains of antagonistic yeasts, is a research topic and eco-friendly management approach that has received considerable attention. A few yeast-based biocontrol products are available in the market. Ecological fitness, stress to...

  17. Agar composition affects in vitro screening of biocontrol activity of antagonistic microorganisms

    NARCIS (Netherlands)

    Bosmans, Lien; De Bruijn, I.; de Mot, Rene; Readers, Hans; Lievens, Bart

    2016-01-01

    Agar-based screening assays are the method of choice when evaluating antagonistic potential of bacterial biocontrol-candidates against pathogens.Weshowed thatwhen using the samemedium, but different agar compositions, the activity of a bacterial antagonist against Agrobacteriumwas strongly affected.

  18. Linking habitat management and conservation biocontrol through gut-content analysis

    Science.gov (United States)

    Increasing the habitat diversity of agricultural fields can lead to more effective biocontrol of arthropod pests. Annual cropping systems are exposed to frequent disturbance and lack habitat diversity; therefore it is important to develop strategies that can improve ecosystem services such as bioco...

  19. [Effect of adaptive biocontrol sessions in the presence of strong professional skill].

    Science.gov (United States)

    Antonov, A A; Ershova, T A; Dudukin, A V

    2011-01-01

    Effect of adaptive biocontrol on efficiency of the operator possessing stable skills in simulating manual control of Soyuz hang-up and berthing to the International space station (ISS) was studied. Job quality was evaluated by the time, energy and precision parameters. The investigation used an ISS computer model and mock-ups of the board operating controls.

  20. Pantoea applied genomics to understand and improve biocontrol activity against fire blight

    Science.gov (United States)

    Pantoea agglomerans and P. vagans (ex. Erwinia herbicola) are common epiphytes of pome fruit flowers and three strains (E325, P10c, C9-1) have been commercially developed as effective biocontrol products for managing fire blight (Erwinia amylovora). Antibiotics as a standard, reliable chemical optio...

  1. Construction of new GFP-tagged fusants for Trichoderma harzianum with enhanced biocontrol activity

    Directory of Open Access Journals (Sweden)

    Kowsari Mojegan

    2014-07-01

    Full Text Available Trichoderma is one of the most exploited biocontrol agents for the management of plant diseases. In biocontrol ecology, the critical factors are detection, and the monitoring and recovery of specific biocontrol agents either naturally present or deliberately released into the environment. Protoplast fusion is an appropriate tool for the improvement of biocontrol Trichoderma strains. Protoplast isolation from Trichoderma harzianum was achieved using 24 h culture age, 6.6 mg/ml Novazym L 1412 at 30°C which resulted the maximum protoplast yield of 5 × 108/ml. The self-fused protoplasts were regenerated and 12 fusants were selected based on their growth rate on 2% colloidal chitin medium. Next, a comparison was done for chitinase and antagonistic activity. Transcriptomic analysis based on quantitative real-time RT-PCR, demonstrated that T8-05 fusant expressed 1.5 fold of chit42 transcript as compared with the parental line. This fusant with 7.02±0.15U chitinase activity showed a higher growth inhibition rate (100% than the parent strain, against Rhizoctonia solani. To obtain a genetically marked fusant that can be used as a biomonitor, the fusant was cotransformed with the gfp and amdS genes. The morphology and viability of selected cotransformant (FT8-7MK-05-2 was similar to the parent. Green fluorescing conidia were observed within the first 2 days of incubation in the soil, and this was followed by the formation of chlamydopores after 60 days. The colonisation of the gfp-tagged fusant was also monitored visually on R. solani sclerotia by scanning electron microscopy. Production of gfp-tagged fusant of Trichoderma spp. provides a potentially useful tool for monitoring hyphal growth patterns and the population of biocontrol agent isolates introduced into environmental systems.

  2. Biocontrol potential of Trichoderma harzianum isolate T-aloe against Sclerotinia sclerotiorum in soybean.

    Science.gov (United States)

    Zhang, Fuli; Ge, Honglian; Zhang, Fan; Guo, Ning; Wang, Yucheng; Chen, Long; Ji, Xiue; Li, Chengwei

    2016-03-01

    Sclerotinia stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary is a major disease of soybean (Glycine max (L.) Merr.). At present, we revealed the three-way interaction between Trichoderma harzianum T-aloe, pathogen S. sclerotiorum and soybean plants in order to demonstrate biocontrol mechanism and evaluate biocontrol potential of T-aloe against S. sclerotiorum in soybean. In our experiments, T-aloe inhibited the growth of S. sclerotiorum with an efficiency of 56.3% in dual culture tests. T-aloe hyphae grew in parallel or intertwined with S. sclerotiorum hyphae and produced hooked contact branches, indicating mycoparasitism. Plate tests showed that T-aloe culture filtrate inhibited S. sclerotiorum growth with an inhibition efficiency of 51.2% and sclerotia production. T-aloe pretreatment showed growth-promoting effect on soybean plants. The activities of peroxidase, superoxide dismutase, and catalase increased, and the hydrogen peroxide (H2O2) as well as the superoxide radical (O2(-)) content in soybean leaves decreased after T-aloe pretreatment in response to S. sclerotiorum pathogen challenge. T-aloe treatment diminished damage caused by pathogen stress on soybean leaf cell membrane, and increased chlorophyll as well as total phenol contents. The defense-related genes PR1, PR2, and PR3 were expressed in the leaves of T-aloe-treated plants. In summary, T-aloe displayed biocontrol potential against S. sclerotiorum. This is the first report of unraveling biocontrol potential of Trichoderma Spp. to soybean sclerotinia stem rot from the three-way interaction between the biocontrol agent, pathogen S. sclerotiorum and soybean plants.

  3. Attachment Capability of Antagonistic Yeast Rhodotorula glutinis to Botrytis cinerea Contributes to Biocontrol Efficacy.

    Science.gov (United States)

    Li, Boqiang; Peng, Huaimin; Tian, Shiping

    2016-01-01

    Rhodotorula glutinis as an antagonism show good biocontrol performance against various post-harvest diseases in fruits. In the present study, strong attachment capability of R. glutinis to spores and hyphae of Botrytis cinerea was observed. Further analysis showed that certain protein components on the yeast cell surface played critical role during the interaction between R. glutinis and B. cinerea. The components mainly distributed at the poles of yeast cells and might contain glycosylation modification, as tunicamycin treated yeast cells lost attachment capability to B. cinerea. To investigate contributions of attachment capability of R. glutinis to its biocontrol efficacy, yeast cells were mutagenized with 3% methane-sulfonic acid ethyl ester (EMS), and a mutant CE4 with stable non-attaching phenotype was obtained. No significant difference was found on colony, cell morphology, reproductive ability, and capsule formation between the mutant and wild-type. However, there was a distinct difference in India ink positive staining patterns between the two strains. Moreover, wild-type strain of R. glutinis showed better performance on inhibiting spore germination and mycelial growth of B. cinerea than CE4 strain when yeast cells and B. cinerea were co-cultured in vitro. In biocontrol assay, both wild-type and CE4 strains showed significant biocontrol efficacy against gray mold caused by B. cinerea in apple fruit, whereas, control effect of CE4 strain was lower than that of wild-type. Our findings provided new evidences that attachment capability of R. glutinis to B. cinerea contributed to its biocontrol efficacy.

  4. Trichoderma Biocontrol: Signal Transduction Pathways Involved in Host Sensing and Mycoparasitism

    Directory of Open Access Journals (Sweden)

    Susanne Zeilinger

    2007-01-01

    Full Text Available Fungi of the genus Trichoderma are used as biocontrol agents against several plant pathogenic fungi like Rhizoctonia spp., Pythium spp., Botrytis cinerea and Fusarium spp. which cause both soil-borne and leaf- or flower-borne diseases of agricultural plants. Plant disease control by Trichoderma is based on complex interactions between Trichoderma, the plant pathogen and the plant. Until now, two main components of biocontrol have been identified: direct activity of Trichoderma against the plant pathogen by mycoparasitism and induced systemic resistance in plants. As the mycoparasitic interaction is host-specific and not merely a contact response, it is likely that signals from the host fungus are recognised by Trichoderma and provoke transcription of mycoparasitism-related genes.In the last few years examination of signalling pathways underlying Trichoderma biocontrol started and it was shown that heterotrimeric G-proteins and mitogen-activated protein (MAP kinases affected biocontrol-relevant processes such as the production of hydrolytic enzymes and antifungal metabolites and the formation of infection structures. MAPK signalling was also found to be involved in induction of plant systemic resistance in Trichoderma virens and in the hyperosmotic stress response in Trichoderma harzianum. Analyses of the function of components of the cAMP pathway during Trichoderma biocontrol revealed that mycoparasitism-associated coiling and chitinase production as well as secondary metabolism are affected by the internal cAMP level; in addition, a cross talk between regulation of light responses and the cAMP signalling pathway was found in Trichoderma atroviride.

  5. Enhanced root colonization and biocontrol activity of Bacillus amyloliquefaciens SQR9 by abrB gene disruption.

    Science.gov (United States)

    Weng, Jun; Wang, Yang; Li, Juan; Shen, Qirong; Zhang, Ruifu

    2013-10-01

    Root colonization by antagonistic bacteria is a prerequisite for successful biological control, and the instability of colonization under varying environmental conditions has accentuated the need to improve the colonization activity. Root colonization by Bacillus spp. is mainly determined by chemotaxis and biofilm formation, and both functions are negatively controlled by the global transcription regulator AbrB. Here, we disrupted the gene abrB in Bacillus amyloliquefaciens SQR9, which has been proven to be a promising biocontrol agent of cucumber and watermelon wilt disease. Chemotaxis, biofilm formation, and colonization activities as well as biocontrol efficiency were measured and compared between the wild-type strain of SQR9 and the abrB mutant. The data presented in this article demonstrate that the colonization and biocontrol activity of B. amyloliquefaciens SQR9 could be significantly improved by abrB gene disruption. The results offer a new strategy to enhance the biocontrol efficacy of B. amyloliquefaciens SQR9.

  6. Growth kinetics and efficacy as parameters for ranking and selecting biocontrol agents that reduce pink rot in stored potatoes

    Science.gov (United States)

    Increased production of organic agricultural products and the relative ineffectiveness of traditional control measures support development of new biocontrol technologies for use against pink rot infections in storage. The microbiota of 84 different agricultural soils was individually transferred to...

  7. Evaluation of the sea anemone Anthothoe albocincta as an augmentative biocontrol agent for biofouling on artificial structures.

    Science.gov (United States)

    Atalah, Javier; Bennett, Holly; Hopkins, Grant A; Forrest, Barrie M

    2013-01-01

    Augmentative biocontrol, defined as the use of indigenous natural enemies to control pest populations, has not been explored extensively in marine systems. This study tested the potential of the anemone Anthothoe albocincta as a biocontrol agent for biofouling on submerged artificial structures. Biofouling biomass was negatively related to anemone cover. Treatments with high anemone cover (>35%) led to significant changes in biofouling assemblages compared to controls. Taxa that contributed to these changes differed among sites, but included reductions in cover of problematic fouling organisms, such as solitary ascidians and bryozoans. In laboratory trials, A. albocincta substantially prevented the settlement of larvae of the bryozoan Bugula neritina when exposed to three levels of larval dose, suggesting predation as an important biocontrol mechanism, in addition to space pre-emption. This study demonstrated that augmentative biocontrol using anemones has the potential to reduce biofouling on marine artificial structures, although considerable further work is required to refine this tool before its application.

  8. Lentinula edodes enhances the biocontrol activity of Cryptococcus laurentii against Penicillium expansum contamination and patulin production in apple fruits.

    Science.gov (United States)

    Tolaini, V; Zjalic, S; Reverberi, M; Fanelli, C; Fabbri, A A; Del Fiore, A; De Rossi, P; Ricelli, A

    2010-04-15

    Penicillium expansum is a post-harvest pathogen of apples which can produce the hazardous mycotoxin patulin. The yeast Cryptococcus laurentii (LS28) is a biocontrol agent able to colonize highly oxidative environments such as wounds in apples. In this study culture filtrates of the basidiomycete Lentinula edodes (LF23) were used to enhance the biocontrol activity of LS28. In vitro L. edodes culture filtrates improved the growth of C. laurentii and the activity of its catalase, superoxide dismutase and glutathione peroxidase, which play a key role in oxidant scavenging. In addition, LF23 also delayed P. expansum conidia germination. The biocontrol effect of LS28 used together with LF23 in wounded apples improved the inhibition of P. expansum growth and patulin production in comparison with LS28 alone, under both experimental and semi-commercial conditions. The biocontrol effect was confirmed by a semi-quantitative PCR analysis set up for monitoring the growth of P. expansum.

  9. 袖珍的麻烦虫%Tiny Troublemaker

    Institute of Scientific and Technical Information of China (English)

    凯瑟琳L·巴克; 韦晴

    2008-01-01

    @@ Don't be fooled by its pretty pattern and comical name-the harlequin ladybug is no joke.This Asian beetle(Brits call them ladybirds)was first seen in England in 2004.Experts wager that it flew or blew in from mainland Europe,where it was introduced in the 1990s to control crop pests.

  10. Test on Predatory Effect of Six Species Ladybird on Semiaphis heraclei Takahashi%6种瓢虫对胡萝卜微管蚜捕食功能反应的测试

    Institute of Scientific and Technical Information of China (English)

    欧善生; 简峰; 苏桂花; 黄雪兰; 石化玉; 黄奉茂; 陈彩贤; 覃连红; 黄艳花

    2011-01-01

    [目的]测试6种瓢虫对胡萝卜微管蚜的捕食功能反应.[方法]在室内分别测试了八斑和瓢虫[ Harmonia octomaculata(Fabricius)]、粗网巧瓢虫[ Denopie chinensis (Weise)]、六斑月瓢虫[Menochilus sexmaculata(Fabriciys)]、红星盘瓢虫[Phrynocaria congener( Billberg)]、龟纹瓢虫[Propyleajaponica (Thunberg)]、狭臀瓢虫[Coccinella transversalis(Fabricius)]6种瓢虫成虫对胡萝卜微管蚜(Semiaphis heracleiTakahashi)的捕食功能反应.[结果]胡萝卜微管蚜的密度与6种瓢虫各1头成虫对相应密度蚜虫的捕食率呈极显著负相关,6种瓢虫成虫对胡萝卜微管蚜的捕食功能反应符合Holling-Ⅱ型反应.八斑和瓢虫、粗网巧瓢虫、六斑月瓢虫、红星盘瓢虫、龟纹瓢虫、狭臀瓢虫各1头成虫对胡萝卜微管蚜的日最大潜在捕食量分别为159.52、193.53、129.57、140.76、120.20、147.34头,其中以粗网巧瓢虫成虫控制蚜虫的潜力最大.[结论]粗网巧瓢虫成虫可作为捕食蚜虫的瓢虫优势种加以保护利用.%[Objective] The aim was to test the predatory effect of six species ladybird on Semiaphis heraclei Takahashi. [ Method] Predatory effects of six species of ladybirds like Harmonia octomaculata Fabricius, Denopie chinensis Weise, Aferwchilus sexmaculata Fabriciys, Phryno caria congener Billberg, Propylea japonica Thunberg and Cocdnella transversalU Fabricius on Semiaphis heraclei Takahashi were tested under indoor conditions. [ Result] There was a negative correlation between the density of 5. Heraclei and predatory rate of each head of six species of ladybirds on corresponding density of aphids. Predatory effects of these six species ladybird on S. Heraclei were coincident with Holling-II type response. The daily max potential predation number of each head of these six species of ladybirds on S. Heraclei was 159. 52, 193. 53, 129.57, 140.76, 120.20 and 147.34 heads, respectively, among them Denopie chinensis Weise showed large

  11. Combining UV-C treatment with biocontrol yeast to control postharvest decay of melon.

    Science.gov (United States)

    Huang, Ke; Zou, Yong; Luo, Jie; Liu, Yiqing

    2015-09-01

    Significant losses in harvested melon can be directly attributable to decay fungi. In the present study, the use of UV-C treatment combined with biocontrol yeast, Pichia cecembensis, was evaluated for their ability to control postharvest decay of melon fruits after they were artificially inoculated with Fusarium oxysporum and Alternaria alternata. Natural infection of fruit was also assessed. As a stand-alone treatment, UV-C or P. cecembensis significantly reduced Fusarium rot and Alternaria rot, and also the level of natural infection on melon fruit, relative to the untreated control. The combination of UV-C or P. cecembensis, however, provided a superior level of decay control on artificially inoculated and naturally infected fruit, compared to either treatment alone. None of the treatments impaired fruit quality. Integrating the use of UV-C treatment with biocontrol yeast has potential as an effective method to control postharvest decay of melon.

  12. Biocontrol Efficacy of Two Antagonistic Yeasts Against Postharvest Diseases in Peach Fruits During Storage Periods

    Institute of Scientific and Technical Information of China (English)

    LIN Li; TIAN Shi-ping; QIN Guo-zheng; XU Yong

    2003-01-01

    Two antagonistic yeasts, Thichosporon pullulans and Cryptococcus laurentii, were investigated for their biocontrol potential to blue mold rot and rhizopus rot on harvested peach fruits (Prunus persica L. Batsch, cv. Okubao), alone or in combination with a Iow dose of iprodione (50 μg mi-1 ). The results indicated that T. pullulans and C. laurentii were effective at reducing disease incidence and severity of blue mold rot and rhizopus rot in peach fruits. Biocontrol efficacy of C. laurentii and T. pullulans were significantly enhanced by combination with a Iow dose of iprodione (50 μg mi-1) against blue mold and rhizopus rot in peach fruits. T. pullulans and C. laurentii combined with a low dose of iprodione (50 μg mi-1 ) resulted in better disease control than either iprodione or the yeasts used alone. Dipping fruits in suspensions of antagonist cells showed the similar control effect as the treatment with iprodione (500 μg ml-1 ).

  13. Multiplication of bio-control agents on locally available organic media

    OpenAIRE

    Devakumar, N.; Shubha, S.; Rao, G.G.E.

    2014-01-01

    Multiplication of micro organisms used as bio control agents can be done by using locally available organic materials viz., compost extract, Jeevamrutha, Press mud, digested biogas slurry only. Performance of bio control agents was better with the combination of digested biogas slurry+ Panchagavya; Press mud + Panchagavya and digested biogas slurry + Press mud. Bio-control agents can be multiplied locally with low cost by adding Jaggery solution.

  14. Biocontrol agents promote growth of potato pathogens, depending on environmental conditions.

    Science.gov (United States)

    Cray, Jonathan A; Connor, Mairéad C; Stevenson, Andrew; Houghton, Jonathan D R; Rangel, Drauzio E N; Cooke, Louise R; Hallsworth, John E

    2016-05-01

    There is a pressing need to understand and optimize biological control so as to avoid over-reliance on the synthetic chemical pesticides that can damage environmental and human health. This study focused on interactions between a novel biocontrol-strain, Bacillus sp. JC12GB43, and potato-pathogenic Phytophthora and Fusarium species. In assays carried out in vitro and on the potato tuber, the bacterium was capable of near-complete inhibition of pathogens. This Bacillus was sufficiently xerotolerant (water activity limit for growth = 0.928) to out-perform Phytophthora infestans (~0.960) and challenge Fusarium coeruleum (~0.847) and Fusarium sambucinum (~0.860) towards the lower limits of their growth windows. Under some conditions, however, strain JC12GB43 stimulated proliferation of the pathogens: for instance, Fusarium coeruleum growth-rate was increased under chaotropic conditions in vitro (132 mM urea) by >100% and on tubers (2-M glycerol) by up to 570%. Culture-based assays involving macromolecule-stabilizing (kosmotropic) compatible solutes provided proof-of-principle that the Bacillus may provide kosmotropic metabolites to the plant pathogen under conditions that destabilize macromolecular systems of the fungal cell. Whilst unprecedented, this finding is consistent with earlier reports that fungi can utilize metabolites derived from bacterial cells. Unless the antimicrobial activities of candidate biocontrol strains are assayed over a full range of field-relevant parameters, biocontrol agents may promote plant pathogen infections and thereby reduce crop yields. These findings indicate that biocontrol activity, therefore, ought to be regarded as a mode-of-behaviour (dependent on prevailing conditions) rather than an inherent property of a bacterial strain.

  15. Trichoderma spp.capable of growing at low temperatures with biocontrol potential

    Institute of Scientific and Technical Information of China (English)

    Szakacs G; Tavaszi A

    2004-01-01

    @@ Though there are successful commercial biocontrol products with Trichoderma spp. In many countries including US, Israel and Europe, their usefulness is limited in cold environments such as mid-and northern part of Europe, US and Canada, especially in the late fall, winter and early spring period.Trichoderma isolates capable of growing at low temperatures (5-10 ℃) and showing good antagonistic properties against plant pathogenic fungi may have therefore both scientific and commercial value.

  16. Field Surveys to Identify Biocontrol Agents of Hydrilla verticillata from June - September 2012

    Science.gov (United States)

    2015-07-01

    the Lijiang River in Guangxi Province and was also not specific, developing on Lagarosiphon alternifolia (Roxb.) Druce, E. nuttallii, Najas marina L...1 Invasion Biology and Biocontrol Lab, Wuhan Botanical Institute, CAS ERDC/TN APCRP-BC-36 July 2015 3 named previously as Bagous sp. 3 and...and 89 larvae). No adults or larvae were extracted from N. marina and Ceratophyllum demersum L. collected in the same survey. In September, 3

  17. Pathogenic fungi and Bio-control agents: Competitive bio-assay research

    OpenAIRE

    2014-01-01

    Fungi of the genus Trichoderma have a track record of being antagonist to quite of a number of agricultural important pathogens. Trichoderma have some unique characteristics that make it scientifically proven and suitable bio-control agents against varieties of pathogenic organism infecting economic food crops. Trichoderma has the advantage of being environment friendly and not hazardous to the health of human beings, livestock, soil and environment. Competitive bio-assay experiment was carri...

  18. Mechanisms involved in biocontrol and plant induced resistance by Trichoderna asperellun (T.harzianum T-203)

    Institute of Scientific and Technical Information of China (English)

    Chet I; Shoresh M; Yedidia I; Viterbo A

    2004-01-01

    @@ Growing awareness of the environmental damage caused by the use of chemical substances for plant disease control in agriculture has raised the need to study biological alternatives, such as activating the defense response of plant crops by inducers not toxic to the environment. Trichoderna spp. are effective biocontrol agents for a number of soilborne pathogens, and are also known for their ability to enhance plant growth and to induce systemic resistance (ISR) in plants.

  19. Mechanism of H₂O₂-induced oxidative stress regulating viability and biocontrol ability of Rhodotorula glutinis.

    Science.gov (United States)

    Chen, Jian; Li, Boqiang; Qin, Guozheng; Tian, Shiping

    2015-01-16

    The use of antagonistic yeasts to control postharvest pathogens is a promising alternative to fungicides. The effectiveness of the antagonists against fungal pathogens is greatly dependent on their viability, which is usually mediated by reactive oxygen species (ROS). Here, we investigated the effects of H₂O₂-induced oxidative stress on the viability and biocontrol efficacy of Rhodotorula glutinis and, using flow cytometric analysis, observed the changes of ROS accumulation and apoptosis in the yeast cells with or without H₂O₂ treatment. We found that the viability of R. glutinis decreased in a time- and dose-dependent manner under H₂O₂-induced oxidative stress. Compared to the control, yeast cells exposed to oxidative stress exhibited more accumulation of ROS and higher levels of protein oxidative damage, but showed lower efficacy for biocontrol of Penicillium expansum causing blue mold rot on peach fruit. The results indicate that apoptosis is a main cause of the cell viability loss in R. glutinis, which is attributed to ROS accumulation under oxidative stress. These findings offer a plausible explanation that oxidative stress affects biocontrol efficacy of R. glutinis via regulating its viability and cell apoptosis.

  20. Isolation of Dickeya dadantii strains from potato disease and biocontrol by their bacteriophages.

    Science.gov (United States)

    Soleimani-Delfan, Abbas; Etemadifar, Zahra; Emtiazi, Giti; Bouzari, Majid

    2015-01-01

    One of the most economically important bacterial pathogens of plants and plant products is Dickeya dadantii. This bacterium causes soft rot disease in tubers and other parts of the potato and other plants of the Solanaceae family. The application of restricted host range bacteriophages as biocontrol agents has recently gained widespread interest. This study purposed to isolate the infectious agent of the potato and evaluate its biocontrol by bacteriophages. Two phytopathogenic strains were isolated from infected potatoes, identified based on biochemical and 16S rRNA gene sequencing, and submitted to GenBank as D. dadantii strain pis3 (accession no. HQ423668) and D. dadantii strain sip4 (accession no. HQ423669). Their bacteriophages were isolated from Caspian Sea water by enriching the water filtrate with D. dadantii strains as hosts using spot or overlay methods. On the basis of morphotypes, the isolated bacteriophages were identified as members of the Myoviridae and Siphoviridae families and could inhibit the growth of antibiotic resistant D. dadantii strains in culture medium. Moreover, in Dickeya infected plants treated with bacteriophage, no disease progression was detected. No significant difference was seen between phage-treated and control plants. Thus, isolated bacteriophages can be suggested for the biocontrol of plant disease caused by Dickeya strains.

  1. Statistical media optimization for the biomass production of postharvest biocontrol yeast Rhodosporidium paludigenum.

    Science.gov (United States)

    Wang, Peng; Liu, Xia; Wang, Yifei; Ruan, Hui; Zheng, XiaoDong

    2011-01-01

    A cane molasses-based medium for the biomass production of biocontrol agent Rhodosporidium paludigenum was statistically optimized. Molasses concentration (after pretreatment), yeast extract, and initial pH were identified by the Plackett-Burman design to show significant influence on the biomass production. The three factors were further optimized by central composite design and response-surface methodology. The statistical analysis indicated the optimum values of the variables were 89.98 g/L for cane molasses, 2.35 g/L for yeast extract and an initial pH of 8.48. The biomass yield at the optimal culture achieved 15.89 g/L in flask fermentation, which was 2.1 times higher than that at the initial NYDB medium. In a 10-L fermenter, 18.97 g/L of biomass was obtained after 36 hr of cultivation. Moreover, the biocontrol efficacy of the yeast was investigated after culture optimization. The results showed the yeast harvested in the optimal medium maintained its initial biocontrol properties by reducing the percentage of decayed apples to below 20%.

  2. Influence of Oxidative Stress on Biocontrol Activity of Cryptococcus laurentii against Blue Mold on Peach Fruit.

    Science.gov (United States)

    Zhang, Zhanquan; Chen, Jian; Li, Boqiang; He, Chang; Chen, Yong; Tian, Shiping

    2017-01-01

    The limitations of chemical fungicides for the control of postharvest diseases have recently become more apparent. The utilization of antagonistic microorganisms is a promising alternative to that of fungicides to control postharvest decay. In previous studies, the antagonistic yeast Cryptococcus laurentii has shown excellent effects of biocontrol and great potential for practical application. Adverse conditions, such as oxidative stress, limit the practical application of antagonistic yeast. In this study, we investigated the oxidative stress tolerance of C. laurentii and the associated mechanisms. The results indicated that exogenous oxidative stress has a significant effect on the viability and biocontrol efficiency of C. laurentii. H2O2-induced oxidative stress led to the accumulation of reactive oxygen species. The results of flow cytometric analysis suggested that apoptosis is responsible for the reduced survival rate of C. laurentii under oxidative stress. Using tests of antioxidant activity, we found that C. laurentii could employ enzymatic systems to resist exogenous oxidative stress. The addition of exogenous glutathione, a non-enzymatic antioxidant, to the media can significantly enhance oxidative tolerance and biocontrol efficiency of C. laurentii.

  3. Influence of Oxidative Stress on Biocontrol Activity of Cryptococcus laurentii against Blue Mold on Peach Fruit

    Science.gov (United States)

    Zhang, Zhanquan; Chen, Jian; Li, Boqiang; He, Chang; Chen, Yong; Tian, Shiping

    2017-01-01

    The limitations of chemical fungicides for the control of postharvest diseases have recently become more apparent. The utilization of antagonistic microorganisms is a promising alternative to that of fungicides to control postharvest decay. In previous studies, the antagonistic yeast Cryptococcus laurentii has shown excellent effects of biocontrol and great potential for practical application. Adverse conditions, such as oxidative stress, limit the practical application of antagonistic yeast. In this study, we investigated the oxidative stress tolerance of C. laurentii and the associated mechanisms. The results indicated that exogenous oxidative stress has a significant effect on the viability and biocontrol efficiency of C. laurentii. H2O2-induced oxidative stress led to the accumulation of reactive oxygen species. The results of flow cytometric analysis suggested that apoptosis is responsible for the reduced survival rate of C. laurentii under oxidative stress. Using tests of antioxidant activity, we found that C. laurentii could employ enzymatic systems to resist exogenous oxidative stress. The addition of exogenous glutathione, a non-enzymatic antioxidant, to the media can significantly enhance oxidative tolerance and biocontrol efficiency of C. laurentii. PMID:28210254

  4. Evaluation of indigenous Trichoderma isolates from Manipur as biocontrol agent against Pythium aphanidermatum on common beans.

    Science.gov (United States)

    Kamala, Th; Indira, S

    2011-12-01

    Pythium aphanidermatum is one of the common causal pathogen of damping-off disease of beans (Phaseolus vulgaris L.) grown in Manipur. A total of 110 indigenous Trichoderma isolates obtained from North east India were screened for their biocontrol activity which can inhibit the mycelial growth of P. aphanidermatum, the causal organism of damping-off in beans. Out of the total isolates, 32% of them showed strong antagonistic activity against P. aphanidermatum under in vitro condition and subsequently 20 best isolates were selected based on their mycelial inhibition capacity against P. aphanidermatum for further analysis. Different biocontrol mechanisms such as protease, chitinase, β-1,3-glucanase activity, cellulase and production of volatile and non-volatile compounds were also assayed. Based on their relative biocontrol potency, only three indigenous Trichoderma isolates (T73, T80 and T105) were selected for pot culture experiment against damping-off diseases in common beans. In greenhouse experiment, Trichoderma isolates T-105 significantly reduced the pre- and post-emergence damping-off disease incidence under artificial infection with P. aphanidermatum and showed highest disease control percentage.

  5. Evaluation of the Biocontrol Potential of Purpureocillium lilacinum QLP12 against Verticillium dahliae in Eggplant

    Science.gov (United States)

    Zhang, Jing; Zong, Zhaofeng

    2017-01-01

    A fungus with broad spectrum antifungal activity was isolated from the soil in Qinling Mountain, Shaanxi Province, in China. The fungus was identified as Purpureocillium lilacinum based on ITS rDNA gene analysis. The strain, coded as QLP12, showed high inhibition activity on fungal mycelium growth in vitro, especially to Mucor piriformis, Trichothecium roseum, Rhizoctonia solani, and Verticillium dahliae, and its potential for biocontrol efficacy of eggplant. Verticillium wilt disease caused by Verticillium dahliae among 10 fungal species tested was explored. In greenhouse experiments, QLP12 showed an excellent growth-promoting effect on eggplant seed germination (76.7%), bud growth (79.4%), chlorophyll content (47.83%), root activity (182.02%), and so on. QLP12 can colonize the eggplant interior and also develop in rhizosphere soil. In greenhouse, the incidence of Verticillium wilt decreased by 83.82% with pretreated QLP12 fermentation broth in the soil. In the field, QLP12 showed prominent biocontrol effects on Verticillium wilt by reducing the disease index over the whole growth period, a decline of 40.1%. This study showed that the strain QLP12 is not only an effective biocontrol agent for controlling Verticillium wilt of eggplant, but also a plant growth-promoting fungus that deserves to be further developed.

  6. Use of mixed cultures of biocontrol agents to control sheep nematodes.

    Science.gov (United States)

    Baloyi, M A; Laing, M D; Yobo, K S

    2012-03-23

    Biological control is a promising non-chemical approach for the control of gastrointestinal nematodes of sheep. Use of combinations of biocontrol agents have been reported to be an effective method to increase the efficacy of biological control effects. In this study, combinations of either two Bacillus thuringiensis (Bt) or Clonostachys rosea (C. rosea) isolates and Bt+C. rosea isolates were evaluated in vitro in microtitre plates for their biocontrol activity on sheep nematodes. The Baermann technique was used to extract the surviving L3 larval stages of intestinal nematodes and counted under a dissecting microscope to determine the larval counts. Results indicate that there was a significant reduction of nematode counts due to combination of biocontrol agents (Pnematodes counts by 72.8%, 64% and 29.8%. The results revealed a control level of 57% when C. rosea isolates P3+P8 were combined. Combination of Bt and C. rosea isolates B10+P8 caused the greatest mortality of 76.7%. Most combinations were antagonistic, with only a few combinations showing an additive effect. None were synergistic. The isolate combinations were more effective than when isolates were used alone.

  7. "Repent, Harlequin!" Said the Ticktockman

    Science.gov (United States)

    Ellison, Harlan

    1973-01-01

    Topic 8, Our Contemporary World: Problems and Issues, in a theme issue on Teaching World History Through Science Fiction, presents this short story to motivate discussion on dehumanization, resulting in a society where the single driving force is order and unity and promptness and clocklike precision. (JB)

  8. Striga Biocontrol on a Toothpick: A Readily Deployable and Inexpensive Method for Smallholder Farmers

    Directory of Open Access Journals (Sweden)

    David Chandler Sands

    2016-08-01

    Full Text Available Striga hermonthica (witchweed is a parasitic weed that attacks and significantly reduces the yields of maize, sorghum, millet and sugarcane throughout sub-Saharan Africa. Low cost management methods such as hand weeding, short crop rotations, trap cropping, or conventional biocontrol have not been effective. Likewise, Striga-tolerant or herbicide-resistant maize cultivars are higher yielding, but are often beyond the economic means of sustenance farmers. The fungal pathogen, Fusarium oxysporum f.sp. strigae, has been the object of numerous studies to develop Striga biocontrol. Under experimental conditions this pathogen can reduce the incidence of Striga infestation but field use is not extensive, perhaps because it has not been sufficiently effective in restoring crop yield and reducing the soil Striga seed bank. Here we brought together Kenyan and US crop scientists with smallholder farmers to develop and validate an effective biocontrol strategy for management of Striga on smallholder farms. Key components of this research project were the following: 1. Development of a two-step method of fungal delivery, including laboratory coating of primary inoculum on toothpicks, followed by on-farm production of secondary field inoculum in boiled rice enabling delivery of vigorous, fresh inoculum directly to the seedbed; 2. Training of smallholder farmers (85% women, to produce the biocontrol agent and incorporate it into their maize plantings in Striga-infested soils and collect agronomic data. The field tests expanded from 30 smallholder farmers to a two-season, 500-farmer plot trial including paired plus and minus biocontrol plots with fertilizer and hybrid seed in both plots and; 3. Concerted selection of variants of the pathogen identified for enhanced virulence, as has been demonstrated in other host parasite systems were employed here on Striga via pathogen excretion of the amino acids L-leucine and L-tyrosine that are toxic to Striga but

  9. Striga Biocontrol on a Toothpick: A Readily Deployable and Inexpensive Method for Smallholder Farmers.

    Science.gov (United States)

    Nzioki, Henry S; Oyosi, Florence; Morris, Cindy E; Kaya, Eylul; Pilgeram, Alice L; Baker, Claire S; Sands, David C

    2016-01-01

    Striga hermonthica (witchweed) is a parasitic weed that attacks and significantly reduces the yields of maize, sorghum, millet, and sugarcane throughout sub-Saharan Africa. Low cost management methods such as hand weeding, short crop rotations, trap cropping, or conventional biocontrol have not been effective. Likewise, Striga-tolerant or herbicide-resistant maize cultivars are higher yielding, but are often beyond the economic means of sustenance farmers. The fungal pathogen, Fusarium oxysporum f.sp. strigae, has been the object of numerous studies to develop Striga biocontrol. Under experimental conditions this pathogen can reduce the incidence of Striga infestation but field use is not extensive, perhaps because it has not been sufficiently effective in restoring crop yield and reducing the soil Striga seed bank. Here we brought together Kenyan and US crop scientists with smallholder farmers to develop and validate an effective biocontrol strategy for management of Striga on smallholder farms. Key components of this research project were the following: (1) Development of a two-step method of fungal delivery, including laboratory coating of primary inoculum on toothpicks, followed by on-farm production of secondary field inoculum in boiled rice enabling delivery of vigorous, fresh inoculum directly to the seedbed; (2) Training of smallholder farmers (85% women), to produce the biocontrol agent and incorporate it into their maize plantings in Striga-infested soils and collect agronomic data. The field tests expanded from 30 smallholder farmers to a two-season, 500-farmer plot trial including paired plus and minus biocontrol plots with fertilizer and hybrid seed in both plots and; (3) Concerted selection of variants of the pathogen identified for enhanced virulence, as has been demonstrated in other host parasite systems were employed here on Striga via pathogen excretion of the amino acids L-leucine and L-tyrosine that are toxic to Striga but innocuous to maize

  10. Striga Biocontrol on a Toothpick: A Readily Deployable and Inexpensive Method for Smallholder Farmers

    Science.gov (United States)

    Nzioki, Henry S.; Oyosi, Florence; Morris, Cindy E.; Kaya, Eylul; Pilgeram, Alice L.; Baker, Claire S.; Sands, David C.

    2016-01-01

    Striga hermonthica (witchweed) is a parasitic weed that attacks and significantly reduces the yields of maize, sorghum, millet, and sugarcane throughout sub-Saharan Africa. Low cost management methods such as hand weeding, short crop rotations, trap cropping, or conventional biocontrol have not been effective. Likewise, Striga-tolerant or herbicide-resistant maize cultivars are higher yielding, but are often beyond the economic means of sustenance farmers. The fungal pathogen, Fusarium oxysporum f.sp. strigae, has been the object of numerous studies to develop Striga biocontrol. Under experimental conditions this pathogen can reduce the incidence of Striga infestation but field use is not extensive, perhaps because it has not been sufficiently effective in restoring crop yield and reducing the soil Striga seed bank. Here we brought together Kenyan and US crop scientists with smallholder farmers to develop and validate an effective biocontrol strategy for management of Striga on smallholder farms. Key components of this research project were the following: (1) Development of a two-step method of fungal delivery, including laboratory coating of primary inoculum on toothpicks, followed by on-farm production of secondary field inoculum in boiled rice enabling delivery of vigorous, fresh inoculum directly to the seedbed; (2) Training of smallholder farmers (85% women), to produce the biocontrol agent and incorporate it into their maize plantings in Striga-infested soils and collect agronomic data. The field tests expanded from 30 smallholder farmers to a two-season, 500-farmer plot trial including paired plus and minus biocontrol plots with fertilizer and hybrid seed in both plots and; (3) Concerted selection of variants of the pathogen identified for enhanced virulence, as has been demonstrated in other host parasite systems were employed here on Striga via pathogen excretion of the amino acids L-leucine and L-tyrosine that are toxic to Striga but innocuous to maize

  11. Phylogeny of certain biocontrol agents with special reference to nematophagous fungi based on RAPd.

    Science.gov (United States)

    Jarullah, B M S; Subramanian, R B; Jummanah, M S J

    2005-01-01

    A number of phylogenetic studies have been carried out on biocontrol agents having similar biological control activity. However, no work has been carried out to determine the phylogenetic relationship amongst various groups of biological control agents with varied biocontrol properties. Our aim was to derive a phylogenetic relationship between diverse biocontrol agents belonging to the deuteromycetes and determine its correlation with their spore morphology and their biocontrol activity. RAPD was used to assess genomic variability in fungi used as biological control agents which included ten isolates of nematophagous fungi such as Arthrobotrys sp., Duddingtonia sp., Paecilomyces sp. and Verticillium sp., along with two isolates of fungal biocontrol agents such as Trichoderma sp. and two isolates of entomopathogenic fungi including Beauveria sp. A plant pathogenic fungus, Verticillium alboatrum was also included to increase the diversity of Deuteromycetes used. A similarity matrix was created using Jaccard's similarity coefficient & clustering was done using unweighted pair group arithmetic mean method (UPGMA). The final dendogram was created using a combination of two programs, Freetree and TreeExplorer. The phylogenetic tree constructed from the RAPD data showed marked genetic variability among different strains of the same species. The spore morphologies of all these fungi were also studied. The phylogenetic pattern could be correlated with the conidial and conidiophore morphology, a criterion commonly used for the classification of fungi in general and Deuteromycetes in particular. Interestingly, the inferred phylogeny showed no significant grouping based on either their biological control properties or the trapping structures amongst the nematophagous fungi as reported earlier by other workers. The phylogenetic pattern was also similar to the tree obtained by comparing the 18S rRNA sequences from the database. The result clearly indicates that the classical

  12. 多食性瓢虫捕食5种蚜虫的统计学比较:实验室研究%COMPARATIVE DEMOGRAPHICS OF A GENERALIST PREDATORY LADYBIRD ON FIVE APHID PREY:A LABORATORY STUDY

    Institute of Scientific and Technical Information of China (English)

    Omkar; Ahmad Pervez

    2004-01-01

    Prey driven demographic parameters of an aphidophagous ladybird, Propylea dissecta (Mulsant) were studied in attempt to answer how ladybird overcomes the problem of seasonally fluctuating food base. The ladybird reared for five generations in laboratory derived differential nutrition from five food sources (i.e. aphid species, Rhopalosiphum maidis (Fitch), Aphis craccivora Koch, Aphis gossypii Glover, Uroleucon compositae (Theobald) and Lipaphis erysimi (Kalt.)). The order of relative prey suitability was A. gossypii, A. craccivora, R. maidis, U. compositae and L.erysimi. Neonates suffered maximum mortality followed by eggs. Estimates of net reproductive rate,intrinsic rate of increase and finite rate of increase were highest (407.18, 0.2274 day-1, 1.2553 day-1) on A. gossypii and lowest (176.02, 0.1533 day-i, 1.1657 day-1) on L. erysimi. Generation time was shortest (26.43 days) on A. gossypii and longest (33.73 days) on L. erysimi. The present study thus,provides an explanation to the high incidence of P. dissecta on A. gossypii, as it experienced high intrinsic rate of increase and optimal values for related demographic parameters.%通过食蚜瓢虫Propylea dissecta(Mulsant)的捕食统计学参数的比较,尝试回答瓢虫是如何克服食物基础季节性的变动问题.在实验室中饲养五世代的瓢虫从五种蚜虫(Rhopalosiphum maidis(Fitch),Aphis craccivora Kock,Aphis gossypii Glover,Uroleucon compositae(Theobald)和Lipaphis erysimi(Kalt))为食物来源获得营养.相对适合的猎物次序是A.gossypii,A.craccivora,R.maidis,U.compositae和L.erysimi.新生幼虫的死亡率最高,其次是卵.统计表明,净生殖率、内懔增长率和有限增长率为(407.18,0.2274天-1,1.2553天-1)最高的在A.gossypii和最低的(176.02,0.1533天-1,1.1657天-1)在L.erysimi,一个世代时间最短的26.43天是捕食A.gossypii;而最长的33.73天为捕食L.erysimi.本研究为P.dissecta捕食A.gossypii高发生提供一种解释,因为它经历了

  13. Functional Investigation of a Non-coding Variant Associated with Adolescent Idiopathic Scoliosis in Zebrafish: Elevated Expression of the Ladybird Homeobox Gene Causes Body Axis Deformation.

    Directory of Open Access Journals (Sweden)

    Long Guo

    2016-01-01

    Full Text Available Previously, we identified an adolescent idiopathic scoliosis susceptibility locus near human ladybird homeobox 1 (LBX1 and FLJ41350 by a genome-wide association study. Here, we characterized the associated non-coding variant and investigated the function of these genes. A chromosome conformation capture assay revealed that the genome region with the most significantly associated single nucleotide polymorphism (rs11190870 physically interacted with the promoter region of LBX1-FLJ41350. The promoter in the direction of LBX1, combined with a 590-bp region including rs11190870, had higher transcriptional activity with the risk allele than that with the non-risk allele in HEK 293T cells. The ubiquitous overexpression of human LBX1 or either of the zebrafish lbx genes (lbx1a, lbx1b, and lbx2, but not FLJ41350, in zebrafish embryos caused body curvature followed by death prior to vertebral column formation. Such body axis deformation was not observed in transcription activator-like effector nucleases mediated knockout zebrafish of lbx1b or lbx2. Mosaic expression of lbx1b driven by the GATA2 minimal promoter and the lbx1b enhancer in zebrafish significantly alleviated the embryonic lethal phenotype to allow observation of the later onset of the spinal curvature with or without vertebral malformation. Deformation of the embryonic body axis by lbx1b overexpression was associated with defects in convergent extension, which is a component of the main axis-elongation machinery in gastrulating embryos. In embryos overexpressing lbx1b, wnt5b, a ligand of the non-canonical Wnt/planar cell polarity (PCP pathway, was significantly downregulated. Injection of mRNA for wnt5b or RhoA, a key downstream effector of Wnt/PCP signaling, rescued the defective convergent extension phenotype and attenuated the lbx1b-induced curvature of the body axis. Thus, our study presents a novel pathological feature of LBX1 and its zebrafish homologs in body axis deformation at

  14. Development of a biocontrol agent for plant disease control with special emphasis on the near commercial fungal antagonist Clonostachys rosea strain "IK726"

    DEFF Research Database (Denmark)

    Jensen, Dan Funck; Knudsen, Inge M.B.; Lübeck, Mette;

    2007-01-01

    . Among the success stories for control of seed- and soilborne diseases are fungal biocontrol agents based on Trichoderma harzianum, Clonostachys rosea and Conithyrium minitans, and bacterial biocontrol agents based on strains of Agrobacterium, Pseudomonas and Streptomyces. We have developed C. rosea...

  15. 七星瓢虫优化算法及其在多学科协同优化中的应用%Seven-spot Ladybird Optimization and its Application in Multidisciplinary Collaborative Optimization

    Institute of Scientific and Technical Information of China (English)

    王鹏; 李洋; 王昆仑

    2015-01-01

    基于对七星瓢虫觅食行为的研究,提出一种新的生物学启发式算法——七星瓢虫优化算法(Seven-spot Ladybird Optimization,SLO).通过6个标准测试函数将其与现有的两种启发式算法(GA、PSO)进行比较,探知其寻优能力.在此基础上,针对多学科设计优化协同优化算法求解效率不高、鲁棒性差等缺陷,将SLO引入协同优化算法系统级优化器,通过工程实例验证了七星瓢虫优化算法良好的寻优能力.

  16. Hrp mutant bacteria as biocontrol agents: toward a sustainable approach in the fight against plant pathogenic bacteria.

    Science.gov (United States)

    Hanemian, Mathieu; Zhou, Binbin; Deslandes, Laurent; Marco, Yves; Trémousaygue, Dominique

    2013-10-01

    Sustainable agriculture necessitates development of environmentally safe methods to protect plants against pathogens. Among these methods, application of biocontrol agents has been efficiently used to minimize disease development. Here we review current understanding of mechanisms involved in biocontrol of the main Gram-phytopathogenic bacteria-induced diseases by plant inoculation with strains mutated in hrp (hypersensitive response and pathogenicity) genes. These mutants are able to penetrate plant tissues and to stimulate basal resistance of plants. Novel protection mechanisms involving the phytohormone abscisic acid appear to play key roles in the biocontrol of wilt disease induced by Ralstonia solanacearum in Arabidopsis thaliana. Fully understanding these mechanisms and extending the studies to other pathosystems are still required to evaluate their importance in disease protection.

  17. Preliminary in vitro insights into the use of natural fungal pathogens of leaf-cutting ants as biocontrol agents.

    Science.gov (United States)

    Folgarait, Patricia; Gorosito, Norma; Poulsen, Michael; Currie, Cameron R

    2011-09-01

    Leaf-cutting ants are one of the main herbivores of the Neotropics, where they represent an important agricultural pest. These ants are particularly difficult to control because of the complex network of microbial symbionts. Leaf-cutting ants have traditionally been controlled through pesticide application, but there is a need for alternative, more environmentally friendly, control methods such as biological control. Potential promising biocontrol candidates include the microfungi Escovopsis spp. (anamorphic Hypocreales), which are specialized pathogens of the fungi the ants cultivate for food. These pathogens are suppressed through ant behaviors and ant-associated antibiotic-producing Actinobacteria. In order to be an effective biocontrol agent, Escovopsis has to overcome these defenses. Here, we evaluate, using microbial in vitro assays, whether defenses in the ant-cultivated fungus strain (Leucoagaricus sp.) and Actinobacteria from the ant pest Acromyrmex lundii have the potential to limit the use of Escovopsis in biocontrol. We also explore, for the first time, possible synergistic biocontrol between Escovopsis and the entomopathogenic fungus Lecanicillium lecanii. All strains of Escovopsis proved to overgrow A. lundii cultivar in less than 7 days, with the Escovopsis strain isolated from a different leaf-cutting ant species being the most efficient. Escovopsis challenged with a Streptomyces strain isolated from A. lundii did not exhibit significant growth inhibition. Both results are encouraging for the use of Escovopsis as a biocontrol agent. Although we found that L. lecanii can suppress the growth of the cultivar, it also had a negative impact on Escovopsis, making the success of simultaneous use of these two fungi for biocontrol of A. lundii questionable.

  18. Characterization of the biocontrol activity of pseudomonas fluorescens strain X reveals novel genes regulated by glucose.

    Directory of Open Access Journals (Sweden)

    Gerasimos F Kremmydas

    Full Text Available Pseudomonas fluorescens strain X, a bacterial isolate from the rhizosphere of bean seedlings, has the ability to suppress damping-off caused by the oomycete Pythium ultimum. To determine the genes controlling the biocontrol activity of strain X, transposon mutagenesis, sequencing and complementation was performed. Results indicate that, biocontrol ability of this isolate is attributed to gcd gene encoding glucose dehydrogenase, genes encoding its co-enzyme pyrroloquinoline quinone (PQQ, and two genes (sup5 and sup6 which seem to be organized in a putative operon. This operon (named supX consists of five genes, one of which encodes a non-ribosomal peptide synthase. A unique binding site for a GntR-type transcriptional factor is localized upstream of the supX putative operon. Synteny comparison of the genes in supX revealed that they are common in the genus Pseudomonas, but with a low degree of similarity. supX shows high similarity only to the mangotoxin operon of Ps. syringae pv. syringae UMAF0158. Quantitative real-time PCR analysis indicated that transcription of supX is strongly reduced in the gcd and PQQ-minus mutants of Ps. fluorescens strain X. On the contrary, transcription of supX in the wild type is enhanced by glucose and transcription levels that appear to be higher during the stationary phase. Gcd, which uses PQQ as a cofactor, catalyses the oxidation of glucose to gluconic acid, which controls the activity of the GntR family of transcriptional factors. The genes in the supX putative operon have not been implicated before in the biocontrol of plant pathogens by pseudomonads. They are involved in the biosynthesis of an antimicrobial compound by Ps. fluorescens strain X and their transcription is controlled by glucose, possibly through the activity of a GntR-type transcriptional factor binding upstream of this putative operon.

  19. Small RNAs regulate the biocontrol property of fluorescent Pseudomonas strain Psd.

    Science.gov (United States)

    Upadhyay, Anamika; Kochar, Mandira; Upadhyay, Ashutosh; Tripathy, Soumya; Rajam, Manchikatla Venkat; Srivastava, Sheela

    2017-03-01

    The production of biocontrol factors by Pseudomonads is reported to be controlled at the post-transcriptional level by the GacS/GacA signal transduction pathway. This involves RNA-binding translational repressor proteins, RsmA and RsmE, and the small regulatory RNAs (sRNAs) RsmX, RsmY, and RsmZ. While the former represses genes involved in secondary metabolite production, the latter relieves this repression at the end of exponential growth. We have studied the fluorescent Pseudomonas strain Psd, possessing good biocontrol potential, and confirmed the presence of rsmY and rsmZ by PCR amplification. Gene constructs for all the three small RNAs (RsmX, RsmY and RsmZ) carried on broad host-range plasmid, pME6032 were mobilized into strain Psd. Expression analysis of gacA in the recombinant strains over-expressing rsmX (Psd-pME7320), rsmY (Psd-pME6359) and rsmZ (Psd-pME6918) revealed a significant upregulation of the response regulator. Besides, a remarkable down-regulation of rsmA was also reported in all the strains. The variant strains were found to produce comparatively higher levels of phenazines. Indole acetic acid levels were higher to some extent, and strain Psd-pME6918 also showed elevated production of HCN. The tomato seedlings infected with Fusarium oxysporum and Verticillium dahliae in the presence of culture filtrate of the recombinant strains showed better plant protection response in comparison to the wild-type strain Psd. These results suggest that small RNAs are important determinants in regulation of the biocontrol property of strain Psd.

  20. Role of gluconic acid production in the regulation of biocontrol traits of Pseudomonas fluorescens CHA0.

    Science.gov (United States)

    de Werra, Patrice; Péchy-Tarr, Maria; Keel, Christoph; Maurhofer, Monika

    2009-06-01

    The rhizobacterium Pseudomonas fluorescens CHA0 promotes the growth of various crop plants and protects them against root diseases caused by pathogenic fungi. The main mechanism of disease suppression by this strain is the production of the antifungal compounds 2,4-diacetylphloroglucinol (DAPG) and pyoluteorin (PLT). Direct plant growth promotion can be achieved through solubilization of inorganic phosphates by the production of organic acids, mainly gluconic acid, which is one of the principal acids produced by Pseudomonas spp. The aim of this study was to elucidate the role of gluconic acid production in CHA0. Therefore, mutants were created with deletions in the genes encoding glucose dehydrogenase (gcd) and gluconate dehydrogenase (gad), required for the conversion of glucose to gluconic acid and gluconic acid to 2-ketogluconate, respectively. These enzymes should be of predominant importance for rhizosphere-colonizing biocontrol bacteria, as major carbon sources provided by plant root exudates are made up of glucose. Our results show that the ability of strain CHA0 to acidify its environment and to solubilize mineral phosphate is strongly dependent on its ability to produce gluconic acid. Moreover, we provide evidence that the formation of gluconic acid by CHA0 completely inhibits the production of PLT and partially inhibits that of DAPG. In the Deltagcd mutant, which does not produce gluconic acid, the enhanced production of antifungal compounds was associated with improved biocontrol activity against take-all disease of wheat, caused by Gaeumannomyces graminis var. tritici. This study provides new evidence for a close association of gluconic acid metabolism with antifungal compound production and biocontrol activity in P. fluorescens CHA0.

  1. Bio-control potential of Cladosporium sp. (MCPL-461), against a noxious weed Parthenium hysterophorus L.

    Science.gov (United States)

    Kumar, Anuj; Verma, V C; Gond, S K; Kumar, V; Kharwar, R N

    2009-03-01

    The phenological survey of Parthenium hysterophorus L., in and around the campus of Banaras Hindu University (BHU) was done for about two years (2004-06). During Nov 2004, a few Parthenium plants were found diseased, and symptoms were restricted to the flowers, buds, and inflorescences. The disease causes sterility and reduces seed viability, which was observed with seed germination test from infected and healthy plants. The fungal pathogen was isolated and identified as Cladosporium sp. (MCPL-461). The severity of pathogen to the reproductive organs led to serious damages of the Parthenium plants. Thus in vitro and in vivo experiments were conducted to determine the bio-control potential of Cladosporium sp. (MCPL 461) against Parthenium weed. A combinatorial effort of Cladosporium sp. (MCPL 461) bio-control potential was evaluated with different culture media, incubation periods and spores strength. Spore suspension of 10(5) to 10(12) spores ml(-1) were used to spray on healthy Parthenium plants, and it was found that severe infection symptoms were appeared at 10(10) to 10(12) spores ml(-1) suspension. LD50 was found at 10(7) spores ml(-1). To enhance the myco-herbicide activity 3% sucrose was added to the spore suspension, which further resolute the bio-control efficacy of the isolates. Only 20-30% seeds of infected plants could germinate. However the safety of non-targeted and wild plants was also tested with Lantana camera, Chromolaena odorata and found that suspension up to 10(12) spores ml(-1) were not sufficient for disease outbreak in them.

  2. Characterization of the biocontrol activity of pseudomonas fluorescens strain X reveals novel genes regulated by glucose.

    Science.gov (United States)

    Kremmydas, Gerasimos F; Tampakaki, Anastasia P; Georgakopoulos, Dimitrios G

    2013-01-01

    Pseudomonas fluorescens strain X, a bacterial isolate from the rhizosphere of bean seedlings, has the ability to suppress damping-off caused by the oomycete Pythium ultimum. To determine the genes controlling the biocontrol activity of strain X, transposon mutagenesis, sequencing and complementation was performed. Results indicate that, biocontrol ability of this isolate is attributed to gcd gene encoding glucose dehydrogenase, genes encoding its co-enzyme pyrroloquinoline quinone (PQQ), and two genes (sup5 and sup6) which seem to be organized in a putative operon. This operon (named supX) consists of five genes, one of which encodes a non-ribosomal peptide synthase. A unique binding site for a GntR-type transcriptional factor is localized upstream of the supX putative operon. Synteny comparison of the genes in supX revealed that they are common in the genus Pseudomonas, but with a low degree of similarity. supX shows high similarity only to the mangotoxin operon of Ps. syringae pv. syringae UMAF0158. Quantitative real-time PCR analysis indicated that transcription of supX is strongly reduced in the gcd and PQQ-minus mutants of Ps. fluorescens strain X. On the contrary, transcription of supX in the wild type is enhanced by glucose and transcription levels that appear to be higher during the stationary phase. Gcd, which uses PQQ as a cofactor, catalyses the oxidation of glucose to gluconic acid, which controls the activity of the GntR family of transcriptional factors. The genes in the supX putative operon have not been implicated before in the biocontrol of plant pathogens by pseudomonads. They are involved in the biosynthesis of an antimicrobial compound by Ps. fluorescens strain X and their transcription is controlled by glucose, possibly through the activity of a GntR-type transcriptional factor binding upstream of this putative operon.

  3. Phaeobacter inhibens as biocontrol agent against Vibrio vulnificus in oyster models

    DEFF Research Database (Denmark)

    Porsby, Cisse Hedegaard; Gram, Lone

    2016-01-01

    acid (TDA), inhibited V. vulnificus as did pure TDA (MIC of 1-3.9 μM). P. inhibens DSM 17395 (at 106 cfu/ml) eradicated 105 cfu/ml V. vulnificus CMCP6 (a rifampicin resistant variant) from a co-culture oyster model system (oyster juice) whereas the pathogen grew to 107 cfu/ml when co......, the presence of P. inhibens could not prevent subsequently added V. vulnificus from entering the live animals, likely because of too low levels of the biocontrol strain. Whilst the oyster model studies provided indication that P. inhibens DSM 17395 could be a good candidate as biocontrol agent against V...

  4. Antagonismo direto e biocontrole da podridão-mole-do-tomateiro pelo uso de procariotas.

    OpenAIRE

    BARRA, V.R.; ROMEIRO, R. da S.; GARCIA, F.A. de O.; Moura,A.B.; SILVA, H. S. A.; MENDONÇA, H.L.; HALFELD-VIEIRA, B. de A.

    2009-01-01

    O objetivo deste trabalho foi avaliar procariotas quanto ao potencial de antagonismo direto para o biocontrole da podridão-mole-do-tomateiro (Pectobacterium carotovorum subsp. carotovorum). Avaliaram-se 45 isolados bacterianos pelo teste de antibiose contra o patógeno. Foram feitos dois ensaios em que sementes de tomate (Lycopersicon esculentum Mill.) cv. Santa Clara foram infectadas com isolados antagônicos. As mudas foram transplantadas para solos infestados com suspensões de propágulos P. ...

  5. Alternethanoxins A and B, polycyclic ethanones produced by Alternaria sonchi , potential mycoherbicides for Sonchus arvensis biocontrol.

    Science.gov (United States)

    Evidente, Antonio; Punzo, Biancavaleria; Andolfi, Anna; Berestetskiy, Alexander; Motta, Andrea

    2009-08-12

    Alternaria sonchi is a fungal pathogen isolated from Sonchus arvensis and proposed as a biocontrol agent of this noxious perennial weed. Different phytotoxic metabolites were isolated from solid culture of the fungus. Two new polycyclic ethanones, named alternethanoxins A and B, were characterized using essentially spectroscopic and chemical methods. Tested by leaf disk-puncture assay on the fungal host plant and a number of nonhost plants, alternethanoxins A and B were shown to be phytotoxic, whereas they did not possess antimicrobial activity tested at 100 microg/disk. Hence, alternethanoxins A and B have potential as nonselective natural herbicides. Some structure-activity relationship observations were also made.

  6. Isolation, characterization, and production of red pigment from Cercospora piaropi a biocontrol agent for waterhyacinth.

    Science.gov (United States)

    Jiménez, Maricela Martínez; Bahena, Selenia Miranda; Espinoza, César; Trigos, Angel

    2010-04-01

    A red pigment produced by a Mexican isolate of Cercospora piaropi (waterhyacinth pathogen) has been isolated and identified as cercosporin. The kinetic of cercosporin production in culture media during dark/light regimes was evaluated. When C. piaropi was cultivated in continuous light and potato dextrose broth culture, a maximum of cercosporin production was observed (72.59 mg/l). Despite other reports, C piaropi Mexican isolate produce cercosporin in dark conditions (25.70 mg/l). The results suggest that production of cercosporin in C. piaropi-waterhyacinth pathogenesis is an important factor to take into account in biocontrol strategies.

  7. [Fungal bio-control agents against ixodid tick--a review].

    Science.gov (United States)

    Sun, Ming; Wang, Xiaoyan; Luo, Jianxun

    2012-08-01

    Entomopathogenic fungi as potential agents for bio-control have been widely applied in the control of insect pests in agriculture. However, the application remains in laboratory scale for the control of ectoparasites. Owing to the need to combat the short lasting period of chemical acaricides and reduction of pollution, it is urgent to develop sufficient, stable and safe measures for tick control. We reviewed the primary scientific achievements in utilization of environmental microbes for controlling of ticks. Studies conducted in this field may benefit to sustainable development, environmental protection, maintaining ecological balance and production of green products.

  8. ROLE OF DRAGONFLY (Brachytron pratense NYMPH AS A BIOCONTROL AGENT OF LARVAL MOSQUITOES

    Directory of Open Access Journals (Sweden)

    G. Chandra

    2012-10-01

    Full Text Available The failure of traditional vector control operations through chemical insecticides renewed interest in biological control method. In the present study Dragonfly (Brachytron pratense nymph has been proved to be a strong biocontrol agent of Anopheles suhpictus larvae in the laboratory condition. Average daily larval feeding rate of B. pratense nymph decreased when the search area was increased. Feeding rate increased when prey density was increased. In the field conditions also, B. pratense played very effective role as predator of different species of larval mosquitoes.

  9. Screening of novel microorganisms for biosurfactant and biocontrol activity against Phytophthora infestans.

    Science.gov (United States)

    Tomar, Sonica; Singh, B P; Lal, Mehi; Ma, Khan; Hussain, Touseef; Sharma, Sanjeev; Kaushik, S K; Kumar, Satish

    2014-09-01

    In the present study, 95 isolates of bacteria were tested for their biosurfactant as well as biocontrol activity against Phytophthora infestans. The results revealed that only 15.8% isolates showed biosurfactant activity. The emulsification index ranged from 0-68% and 24.2% isolates showed positive reaction for biosurfactant properties. In emulsification assay and oil spreading test, 18.95% and 5.26% isolates, respectively scored positive for biosurfactant production. Among all, only five isolates were found effective against P. infestans, for biocontrol properties. Pseudomonas aeruginosa-1 showed 62.22% inhibition zone after 72 hrs while P. aeruginosa-3 showed 46.42%. Forty-eight hrs old culture supernatants were highly effective in food-poisoning test, tuber slice test and detached leaf method against P. infestans. In whole potato plant test, bacterial cell based formulation, culture supernatant and bacterial cell suspension of P. aeruginosa-1 showed 10.42%, 9.94% and 17.96% diseases severity respectively, as against 53.96% in control. This isolate holds promise as biological control agent against P. infestans in field.

  10. Biofertilization and Biocontrol in the fight against soilborne fungal root pathogens in Australian soils

    Science.gov (United States)

    Cooper, Sarah; Agnew, Linda; Pereg, Lily

    2015-04-01

    Control of soilborne fungal root pathogens that severely compromise cotton production and other crops worldwide has historically been through the use of synthetic fungicides and fertilizers, these often have hazardous implications for environmental and soil health. The search for sustainable alternatives has lead to heightened interest in biocontrol, using soil microorganisms that suppress the growth of phytopathogens directly and biofertilization, the use of microorganisms to increasing the nutrient availability in soils, increasing seedling vigour. Soil properties and consequently soil microbial properties are strongly impacted by agricultural practices, therefore we are isolating indigenous microorganisms from soils collected from ten different geographical locations within the Australian cotton-growing region. These differ vastly in soil type and management practices. Soils are being analysed to compare the abundance of phosphate solubilising, auxin producing and nitrogen cycling bacteria. Rhizospheric bacteria capable of plant growth promoting through a multiple actions are being isolated. In addition, a method for isolating soilborne fungal suppressive microbes directly from soil samples has been designed and is currently being used. Comparisons between agricultural practices and the plant growth promoting microbial component of soil microbiome will be reported on. We will discuss the microbial isolates identified, their modes of action and their potential use as biocontrol agents and/or biofertilizers in Australian cotton growing soils.

  11. Strain-level diversity of secondary metabolism in the biocontrol species Aneurinibacillus migulanus.

    Science.gov (United States)

    Alenezi, Faizah N; Rekik, Imen; Bełka, Marta; Ibrahim, Abrar F; Luptakova, Lenka; Jaspars, Marcel; Woodward, Steve; Belbahri, Lassaad

    2016-01-01

    Aneurinibacillus migulanus strains Nagano and NCTC 7096 show potential in biocontrol against fungal and fungus-like plant pathogens, including a wide range of Ascomycota, Basidiomycota, and Oomycetes. Differences in terms of the range of pathogens that each strain inhibits, however, suggested that production of a single antibiotic cyclic peptide, gramicidin S (GS), by the two strains, is not the sole mechanism of inhibition. The availability of four sequenced genomes of Aneurinibacillus prompted us to apply genome mining techniques to identify the bioactive potential of A. migulanus and to provide insights into the secondary metabolite arsenal of the genus Aneurinibacillus. Up to eleven secondary metabolite biosynthetic gene clusters were present in the three Aneurinibacillus species. Biosynthetic gene clusters specifying bacteriocins, microcins, non-ribosomal peptides, polyketides, terpenes, phosphonates, lasso peptides and linaridins were identified. Chitinolytic potential and iron metabolism regulation were also investigated. With increasing numbers of biocontrol bacterial genomes being sequenced and mined, the use of approaches similar to those described in this paper will lead to an increase in the numbers of environmentally friendly natural products available to use against plant diseases.

  12. Tamarisk biocontrol using tamarisk beetles: Potential consequences for riparian birds in the southwestern United States

    Science.gov (United States)

    Paxton, Eben H.; Theimer, Tad C.; Sogge, Mark K.

    2011-01-01

    The tamarisk beetle (Diorhabda spp.), a non-native biocontrol agent, has been introduced to eradicate tamarisk (Tamarix spp.), a genus of non-native tree that has become a dominant component of riparian woodlands in the southwestern United States. Tamarisk beetles have the potential to spread widely and defoliate large expanses of tamarisk habitat, but the effects of such a widespread loss of riparian vegetation on birds remains unknown. We reviewed literature on the effects of other defoliating insects on birds to investigate the potential for tamarisk beetles to affect birds positively or negatively by changing food abundance and vegetation structure. We then combined data on the temporal patterns of tamarisk defoliation by beetles with nest productivity of a well-studied riparian obligate, the Southwestern Willow Flycatcher (Empidonax traillii extimus), to simulate the potential demographic consequences of beetle defoliation on breeding riparian birds in both the short and long term. Our results highlight that the effects of tamarisk biocontrol on birds will likely vary by species and population, depending upon its sensitivity to seasonal defoliation by beetles and net loss of riparian habitat due to tamarisk mortality. Species with restricted distributions that include areas dominated by tamarisk may be negatively affected both in the short and long term. The rate of regeneration and/or restoration of native cottonwoods (Populus spp.) and willows (Salix spp.) relative to the rate of tamarisk loss will be critical in determining the long-term effect of this large-scale ecological experiment.

  13. Diversity, Biocontrol, and Plant Growth Promoting Abilities of Xylem Residing Bacteria from Solanaceous Crops

    Directory of Open Access Journals (Sweden)

    Gauri A. Achari

    2014-01-01

    Full Text Available Eggplant (Solanum melongena L. is one of the solanaceous crops of economic and cultural importance and is widely cultivated in the state of Goa, India. Eggplant cultivation is severely affected by bacterial wilt caused by Ralstonia solanacearum that colonizes the xylem tissue. In this study, 167 bacteria were isolated from the xylem of healthy eggplant, chilli, and Solanum torvum Sw. by vacuum infiltration and maceration. Amplified rDNA restriction analysis (ARDRA grouped these xylem residing bacteria (XRB into 38 haplotypes. Twenty-eight strains inhibited growth of R. solanacearum and produced volatile and diffusible antagonistic compounds and plant growth promoting substances in vitro. Antagonistic strains XB86, XB169, XB177, and XB200 recorded a biocontrol efficacy greater than 85% against BW and exhibited 12%–22 % increase in shoot length in eggplant in the greenhouse screening. 16S rRNA based identification revealed the presence of 23 different bacterial genera. XRB with high biocontrol and plant growth promoting activities were identified as strains of Staphylococcus sp., Bacillus sp., Streptomyces sp., Enterobacter sp., and Agrobacterium sp. This study is the first report on identity of bacteria from the xylem of solanaceous crops having traits useful in cultivation of eggplant.

  14. Biocontrol activity of Paenibacillus polymyxa AC-1 against Pseudomonas syringae and its interaction with Arabidopsis thaliana.

    Science.gov (United States)

    Hong, Chi Eun; Kwon, Suk Yoon; Park, Jeong Mee

    2016-04-01

    Paenibacillus polymyxa AC-1 (AC-1) is a plant growth-promoting rhizobacterium (PGPR) that has been used as a soil inoculant for biocontrol of plant pathogenic fungi and to promote plant growth. In this study, we examine the effects of AC-1 on the bacterial phytopathogen Pseudomonas syringae and internal colonization of AC-1 by counting bacterial populations that colonize plants. AC-1 inhibited the growth of both P. syringae pv. tomato DC3000 (Pst) and P. syringae pv. tabaci (Pta) in a concentration-dependent manner in in vitro assays. Upon treatment of AC-1 dropping at root tip of axenically grown Arabidopsis, we found that most of the AC-1 was detected in interior of leaves of Arabidiopsis plants rather than roots after 5 days post infection, indicating systemic spreading of AC-1 occur. We examined further AC-1 colonization patterns in Arabidopsis mutants deficient in phytohormone signaling pathways. These results indicated that abscisic acid (ABA) and jasmonic acid (JA) signaling pathways positively and negatively contributed, respectively, to AC-1 colonization of leaves, whereas epiphytic accumulation of AC-1 around root tissues was not affected. This study shows that AC-1 is an effective biocontrol agent to suppress P. syringae growth, possibly owing to its colonization patterns as a leaf-inhabiting endophyte. The results showed in this work will help to expand our understanding of the mode of action of AC-1 as a biological control agent and consequently, its application in agriculture.

  15. SCREENING OF FLUORESCENT RHIZOBACTERIA FOR THE BIOCONTROL OF SOILBORNE PLANT PATHOGENIC FUNGI

    Directory of Open Access Journals (Sweden)

    ANELISE DIAS

    2014-01-01

    Full Text Available The biocontrol of soilborne plant pathogens represents a promising approach from the environ- mental and practical points of view. Fluorescent pseudomonad rhizobacteria are well known by their antagonis- tic capacity towards several plant pathogens due to a diversity of antimicrobial metabolites they produce. This study was conceived to select and characterize rhizobacteria having antagonistic potential towards the patho- genic fungi Rhizoctonia solani and Sclerotium rolfsii. A total of 94 bacterial strains isolated from the rhizospheres of four vegetable species under organic cultivation were evaluated. Twenty-two strains which predominate in lettuce and rudbeckia rhizospheres showed identical biochemical profiles to Pseudomonas fluo- rescens, while in kale and parsley rhizospheres identical profiles to Pseudomonas putida (subgroups A and B strains prevailed. Two types of antagonism were verified in vitro and defined as competition and inhibition of mycelial growth. Sixty percent of the evaluated strains showed antagonistic potential and, among those, 24 strains expressed antagonism to both target fungi, with P. fluorescens being the most representative bacterial species. This work clearly identified a number of strains with potential for use as plant growth-promoting and biocontrol of the two soilborne fungal pathogens in vegetable crops production systems.

  16. Enhanced biocontrol activity of Trichoderma through inactivation of a mitogen-activated protein kinase

    Science.gov (United States)

    Mendoza-Mendoza, Artemio; Pozo, María J.; Grzegorski, Darlene; Martínez, Pedro; García, Juan M.; Olmedo-Monfil, Vianey; Cortés, Carlos; Kenerley, Charles; Herrera-Estrella, Alfredo

    2003-01-01

    The production of lytic enzymes in Trichoderma is considered determinant in its parasitic response against fungal species. A mitogen-activated protein kinase encoding gene, tvk1, from Trichoderma virens was cloned, and its role during the mycoparasitism, conidiation, and biocontrol was examined in tvk1 null mutants. These mutants showed a clear increase in the level of the expression of mycoparasitism-related genes under simulated mycoparasitism and during direct confrontation with the plant pathogen Rhizoctonia solani. The null mutants displayed an increased protein secretion phenotype as measured by the production of lytic enzymes in culture supernatant compared to the wild type. Consistently, biocontrol assays demonstrated that the null mutants were considerably more effective in disease control than the wild-type strain or a chemical fungicide. In addition, tvk1 gene disruptant strains sporulated abundantly in submerged cultures, a condition that is not conducive to sporulation in the wild type. These data suggest that Tvk1 acts as a negative modulator during host sensing and sporulation in T. virens. PMID:14673101

  17. Toxicology, biosynthesis, bio-control of aflatoxin and new methods of detection

    Institute of Scientific and Technical Information of China (English)

    Mohamed Amine Gacem; Aminata Ould El Hadj-Khelil

    2016-01-01

    Mycotoxins and their derivatives since their discoveries and until the present time are behind unspecified economic and medical damages. Aflatoxins are classified according to their physical–chemical and toxicological characters in the most dangerous row of the mycotoxins. These aflatoxins are in part responsible, of irreversible medical disasters that are not easily manageable such as cancer of the liver and kidneys, and in the other part, of losses in the stored cereal products. Based on these crucial findings, monitoring of this toxin became imperative in post-harvest food products, during storage, during trans-formation chain and even during the long phases of conservation. Vigilance of this toxin is delivered by detection methods using very advanced technologies to respond in the shortest possible times. In addition, the knowledge of factors supporting the biosynthesis of aflatoxins such as the temperature, moisture content, concentration of nitrogen and carbon, and the molecules responsible for the genetic control of the synthesis will be reflected later in the choice of bio-control techniques. This control is currently based on new strategies using the bioactives substances of the plants, the lactic bacteria and some strains of actinomycetes that have good inhibiting activity against aflatoxins with fewer side effects on Man. On the other hand, this brief review summarizes the results of new studies demonstrating the toxicity of the toxin, new detection methods and bio-control.

  18. Bio-control trials of Chaetomium spirale ND35 against apple canker

    Institute of Scientific and Technical Information of China (English)

    XINYa-fen; SHANGJin-jie

    2005-01-01

    A new endophytic antagonistic fungus, Chaetomium spirale ND35 from Populus tomentosa, was reported. The bio-control trials of C. spirale ND35 against the Valsa Canker of apple were preliminarily investigated. The results of dual culture on PDA plate showed that C. spirale ND35 was capable of strong antagonism against Valsa ceratosperma, and for inhibiting the mycelial growth of V. ceratosperma,.the crude extract of liquid culture of corn steep powder broth was more effective than that one of malt extract broth (MEB). The results of bio-control in greenhouse and field indicated that the disease incidence of apple tree treated with C. spirale ND35 was lower significantly than that treated by other methods. The re-isolation experiment suggested that C. spirale ND35 could colonize in stems and branches of apple trees successfully, and the ND35 colonization rate of the treatment with solid wheat bran culture was higher than that of corn steep powder broth, but the field experiment result the control effect of liquid culture of C. spirale ND35 was better than that of solid culture.

  19. Relationship between mycoparasites lifestyles and biocontrol behaviors against Fusarium spp. and mycotoxins production.

    Science.gov (United States)

    Kim, Seon Hwa; Vujanovic, Vladimir

    2016-06-01

    Global food security research is seeking eco-friendly solutions to control mycotoxins in grain infected by fungi (molds). In particular, mycotoxigenic Fusarium spp. outbreak is a chronic threat for cereal grain production, human, and animal health. In this review paper, we discuss up-to-date biological control strategies in applying mycoparasites as biological control agents (BCA) to prevent plant diseases in crops and mycotoxins in grain, food, and feed. The aim is to increase food safety and to minimize economic losses due to the reduced grain yield and quality. However, recent papers indicate that the study of the BCA specialists with biotrophic lifestyle lags behind our understanding of the BCA generalists with necrotrophic lifestyle. We examine critical behavioral traits of the two BCA groups of mycoparasites. The goal is to highlight their major characteristics in the context of future research towards an efficient biocontrol strategy against mycotoxin-producing Fusarium species. The emphasis is put on biocontrol of Fusarium graminearum, F. avenaceum, and F. culmorum causing Fusarium head blight (FHB) in cereals and their mycotoxins.

  20. Toxicology, biosynthesis, bio-control of aflatoxin and new methods of detection

    Directory of Open Access Journals (Sweden)

    Mohamed Amine Gacem

    2016-09-01

    Full Text Available Mycotoxins and their derivatives since their discoveries and until the present time are behind unspecified economic and medical damages. Aflatoxins are classified according to their physical–chemical and toxicological characters in the most dangerous row of the mycotoxins. These aflatoxins are in part responsible, of irreversible medical disasters that are not easily manageable such as cancer of the liver and kidneys, and in the other part, of losses in the stored cereal products. Based on these crucial findings, monitoring of this toxin became imperative in post-harvest food products, during storage, during transformation chain and even during the long phases of conservation. Vigilance of this toxin is delivered by detection methods using very advanced technologies to respond in the shortest possible times. In addition, the knowledge of factors supporting the biosynthesis of aflatoxins such as the temperature, moisture content, concentration of nitrogen and carbon, and the molecules responsible for the genetic control of the synthesis will be reflected later in the choice of bio-control techniques. This control is currently based on new strategies using the bioactives substances of the plants, the lactic bacteria and some strains of actinomycetes that have good inhibiting activity against aflatoxins with fewer side effects on Man. On the other hand, this brief review summarizes the results of new studies demonstrating the toxicity of the toxin, new detection methods and bio-control.

  1. Phaeobacter inhibens as biocontrol agent against Vibrio vulnificus in oyster models.

    Science.gov (United States)

    Porsby, Cisse Hedegaard; Gram, Lone

    2016-08-01

    Molluscan shellfish can cause food borne diseases and here we investigated if addition of Vibrio-antagonising bacteria could reduce Vibrio vulnificus in model oyster systems and prevent its establishment in live animals. Phaeobacter inhibens, which produces an antibacterial compound, tropodithietic acid (TDA), inhibited V. vulnificus as did pure TDA (MIC of 1-3.9 μM). P. inhibens DSM 17395 (at 10(6) cfu/ml) eradicated 10(5) cfu/ml V. vulnificus CMCP6 (a rifampicin resistant variant) from a co-culture oyster model system (oyster juice) whereas the pathogen grew to 10(7) cfu/ml when co-cultured with a TDA negative Phaeobacter mutant. P. inhibens grew well in oyster juice to 10(8) CFU/ml and sterile filtered samples from these cultures were inhibitory to Vibrio spp. P. inhibens established itself in live European flat oysters (Ostrea edulis) and remained at 10(5) cfu/g for five days. However, the presence of P. inhibens could not prevent subsequently added V. vulnificus from entering the live animals, likely because of too low levels of the biocontrol strain. Whilst the oyster model studies provided indication that P. inhibens DSM 17395 could be a good candidate as biocontrol agent against V. vulnificus further optimization is need in the actual animal rearing situation.

  2. Screening for Pseudomonas and Bacillus antagonistic rhizobacteria strains for the biocontrol of Fusarium wilt of chickpea

    Directory of Open Access Journals (Sweden)

    Hannane Abed

    2016-07-01

    Full Text Available The aim of this work is to study the ability of several isolates belonging to Rhizobacteria (Pseudomonas and Bacillus collected from several chickpea growing areas in Algeria, to control the mycelium growth of Fusarium oxysporum f. sp. ciceris. Interesting isolates were characterized for their morphological characteristics, physiological and biochemical activities as potential bio-control agent. Fungal inhibition tests were performed using plate assay and each isolate were tested for the production of protease, cyanide hydrogen, indole acetic acid, antifungal volatile and extracellular compound. According to API 50 CH, we are able to identify six Bacillus species (B. subtilis, B. circulans, B. lentus, B. aneurinilyticus, B. firmus, B. licheniformis; and with API 20NE test we have identified three Pseudomonas species (P. aeruginosa, P. luteola, P. fluorescens. The ability of bacterial isolates was varied in production of Protease, Gelatinase, Amylase, Cellulase, Acid Indole acetic, Lipase, Catalase and Cyanid Hydrogen. This is traduced in different rate of inhibition growth due to various extracellular compounds, where B61 (Bacillus aneurinilyticus and P39 (Pseudomonas luteola and P70 (Pseudomonas fluorescens were the most efficient with 77 and 55.5% respectively, while B39 (Bacillus firmus and P41 (Pseudomonas luteola were the most efficient by volatile compounds with 70.5 and 77.5% respectively. Our results indicate that these bacteria isolates can be used in the biocontrol of Fusarium oxysporum f. sp. ciceris.

  3. Systematics of the Trichoderma harzianum species complex and the re-identification of commercial biocontrol strains.

    Science.gov (United States)

    Chaverri, Priscila; Branco-Rocha, Fabiano; Jaklitsch, Walter; Gazis, Romina; Degenkolb, Thomas; Samuels, Gary J

    2015-01-01

    Trichoderma harzianum is known as a cosmopolitan, ubiquitous species associated with a wide variety of substrates. It is possibly the most commonly used name in agricultural applications involving Trichoderma, including biological control of plant diseases. While various studies have suggested that T. harzianum is a species complex, only a few cryptic species are named. In the present study the taxonomy of the T. harzianum species complex is revised to include at least 14 species. Previously named species included in the complex are T. guizhouense, T. harzianum, and T. inhamatum. Two new combinations are proposed, T. lentiforme and T. lixii. Nine species are described as new, T. afarasin, T. afroharzianum, T. atrobrunneum, T. camerunense, T. endophyticum, T. neotropicale, T. pyramidale, T. rifaii and T. simmonsii. We isolated Trichoderma cultures from four commercial biocontrol products reported to contain T. harzianum. None of the biocontrol strains were identified as T. harzianum s. str. In addition, the widely applied culture 'T. harzianum T22' was determined to be T. afroharzianum. Some species in the T. harzianum complex appear to be exclusively endophytic, while others were only isolated from soil. Sexual states are rare. Descriptions and illustrations are provided. A secondary barcode, nuc translation elongation factor 1-α (TEF1) is needed to identify species in this complex.

  4. Plant growth-promoting rhizobacteria (PGPR: their potential as antagonists and biocontrol agents

    Directory of Open Access Journals (Sweden)

    Anelise Beneduzi

    2012-01-01

    Full Text Available Bacteria that colonize plant roots and promote plant growth are referred to as plant growth-promoting rhizobacteria (PGPR. PGPR are highly diverse and in this review we focus on rhizobacteria as biocontrol agents. Their effects can occur via local antagonism to soil-borne pathogens or by induction of systemic resistance against pathogens throughout the entire plant. Several substances produced by antagonistic rhizobacteria have been related to pathogen control and indirect promotion of growth in many plants, such as siderophores and antibiotics. Induced systemic resistance (ISR in plants resembles pathogen-induced systemic acquired resistance (SAR under conditions where the inducing bacteria and the challenging pathogen remain spatially separated. Both types of induced resistance render uninfected plant parts more resistant to pathogens in several plant species. Rhizobacteria induce resistance through the salicylic acid-dependent SAR pathway, or require jasmonic acid and ethylene perception from the plant for ISR. Rhizobacteria belonging to the genera Pseudomonas and Bacillus are well known for their antagonistic effects and their ability to trigger ISR. Resistance-inducing and antagonistic rhizobacteria might be useful in formulating new inoculants with combinations of different mechanisms of action, leading to a more efficient use for biocontrol strategies to improve cropping systems.

  5. Involvement of fengycin-type lipopeptides in the multifaceted biocontrol potential of Bacillus subtilis.

    Science.gov (United States)

    Ongena, Marc; Jacques, Philippe; Touré, Yacine; Destain, Jacqueline; Jabrane, Abdelhamid; Thonart, Philippe

    2005-11-01

    In this work, the potential of Bacillus subtilis strain M4 at protecting plants against fungal diseases was demonstrated in different pathosystems. We provide evidence for the role of secreted lipopeptides, and more particularly of fengycins, in the protective effect afforded by the strain against damping-off of bean seedlings caused by Pythium ultimum and against gray mold of apple in post-harvest disease. This role was demonstrated by the strong biocontrol activity of lipopeptide-enriched extracts and through the detection of inhibitory quantities of fengycins in infected tissues. Beside such a direct antagonism of the pathogen, we show that root pre-inoculation with M4 enabled the host plant to react more efficiently to subsequent pathogen infection on leaves. Fengycins could also be involved in this systemic resistance-eliciting effect of strain M4, as these molecules may induce the synthesis of plant phenolics involved in or derived from the defense-related phenylpropanoid metabolism. Much remains to be discovered about the mechanisms by which Bacillus spp suppress disease. Through this study on strain M4, we reinforce the interest in B. subtilis as a pathogen antagonist and plant defense-inducing agent. The secretion of cyclic fengycin-type lipopeptides may be tightly related to the expression of these two biocontrol traits.

  6. Characterization of CMR5c and CMR12a, novel fluorescent Pseudomonas strains from the cocoyam rhizosphere with biocontrol activity

    NARCIS (Netherlands)

    Perneel, M.; Heyrman, J.; Adiobo, A.; Maeyer, de K.; Raaijmakers, J.M.; Vos, de P.; Höfte, M.

    2007-01-01

    Aim: To screen for novel antagonistic Pseudomonas strains producing both phenazines and biosurfactants that are as effective as Pseudomonas aeruginosa PNA1 in the biocontrol of cocoyam root rot caused by Pythium myriotylum. Material and Results: Forty pseudomonads were isolated from the rhizosphere

  7. Non-aflatoxigenic Aspergillus flavus as potential biocontrol agents to reduce aflatoxin contamination in peanuts harvested in Northern Argentina.

    Science.gov (United States)

    Alaniz Zanon, María Silvina; Barros, Germán Gustavo; Chulze, Sofía Noemí

    2016-08-16

    Biological control is one of the most promising strategies for preventing aflatoxin contamination in peanuts at field stage. A population of 46 native Aspergillus flavus nonaflatoxin producers were analysed based on phenotypic, physiological and genetic characteristics. Thirty-three isolates were characterized as L strain morphotype, 3 isolates as S strain morphotype, and 10 isolates did not produce sclerotia. Only 11 of 46 non-aflatoxigenic isolates did not produce cyclopiazonic acid. The vegetative compatibility group (VCG) diversity index for the population was 0.37. For field trials we selected the non-aflatoxigenic A. flavus AR27, AR100G and AFCHG2 strains. The efficacy of single and mixed inocula as potential biocontrol agents in Northern Argentina was evaluated through a 2-year study (2014-2015). During the 2014 peanut growing season, most of the treatments reduced the incidence of aflatoxigenic strains in both soil and peanut kernel samples, and no aflatoxin was detected in kernels. During the 2015 growing season, there was a reduction of aflatoxigenic strains in kernel samples from the plots treated with the potential biocontrol agents. Reductions of aflatoxin contamination between 78.36% and 89.55% were observed in treated plots in comparison with the un-inoculated control plots. This study provides the first data on aflatoxin biocontrol based on competitive exclusion in the peanut growing region of Northern Argentina, and proposes bioproducts with potential use as biocontrol agents.

  8. Potential of osmoadaptation for improving Pantoea agglomerans E325 as biocontrol agent for fire blight of apple and pear

    Science.gov (United States)

    Pantoea agglomerans biocontrol strain E325 is the active ingredient in a commercial product for fire blight, a destructive disease of apple and pear initiated by Erwinia amylovora in flowers. Osmoadaptation, involving the combination of saline osmotic stress and osmolyte amendment to growth media, w...

  9. Conidial quality of the biocontrol agent Coniothyrium minitans produced by solid-state cultivation in a packed-bed reactor

    NARCIS (Netherlands)

    Jones, E.E.; Weber, F.J.; Oostra, J.; Rinzema, A.; Mead, A.; Whipps, J.M.

    2004-01-01

    Conidial germination and novel sand- and soil-based sclerotial parasitism assays were used to test the quality of conidial inoculum of the biocontrol agent Coniothyrium minitans IVT1 produced in different packed bed reactor runs. The fermenter airflow rate was either kept constant, resulting in a tr

  10. Survival of Salmonella Typhimurium on soybean sprouts after treatment with gaseous chlorine dioxide and biocontrol Pseudomonas bacteria

    Science.gov (United States)

    Control of Salmonella Typhimurium on sprouts and minimally processed produce is crucial for food and consumer safety. The aim of this research was to assess natural microflora populations on soybean and evaluate the effects of gaseous chlorine dioxide (ClO2) and biocontrol Pseudomonas on the surviva...

  11. Inability to Find Consistent Bacterial Biocontrol Agents of Pythium aphanidermatum in Cucumber Using Screens Based on Ecophysiological Traits

    NARCIS (Netherlands)

    Folman, L.B.; Postma, J.; Veen, van J.A.

    2003-01-01

    A collection of 821 rhizobacteria from cucumber, originating from different root locations and stages of plant development, was screened for potential biocontrol agents of Pythium aphanidermatum (Edson) Fitzp. The screening procedure exploited carbon source utilization profiles and growth rates of b

  12. Inability to find consistent bacterial biocontrol agents of Pythium aphanidermatum in cucumber using screens based on ecophysiological traits

    NARCIS (Netherlands)

    Folman, L.B.; Postma, J.; Van Veen, J.A.

    2003-01-01

    A collection of 821 rhizobacteria from cucumber, originating from different root locations and stages of plant development, was screened for potential biocontrol agents of Pythium aphanidermatum (Edson) Fitzp. The screening procedure exploited carbon source utilization profiles and growth rates of b

  13. Phytohormone profiles induced by Trichoderma isolates correspond with their biocontrol and plant growth-promoting activity on melon plants

    NARCIS (Netherlands)

    Martínez-Medina, Ainhoa; Del Mar Alguacil, Maria; Pascual, Jose A.; van Wees, Saskia C M

    2014-01-01

    The application of Trichoderma strains with biocontrol and plant growth-promoting capacities to plant substrates can help reduce the input of chemical pesticides and fertilizers in agriculture. Some Trichoderma isolates can directly affect plant pathogens, but they also are known to influence the ph

  14. Involvement of phenazines and biosurfactants in biocontrol of Pythium myriotylum root rot on cocoyam by Pseudomonas sp. CMR12A

    Science.gov (United States)

    Pseudomonas sp. CMR12a was isolated from the rhizosphere of the tropical tuber crop cocoyam and produces both phenazines and cyclic lipopeptide (CLP) biosurfactants. CMR12a was shown to be an efficient biocontrol agent of P. myriotylum on cocoyam. To assess the importance of phenazine and biosurfact...

  15. Survival of Salmonella enterica on soybean sprouts following treatments with gaseous chlorine dioxide and biocontrol Pseudomonas bacteria

    Science.gov (United States)

    Control of Salmonella enterica on sprouts and minimally processed, ready-to-eat fruits and vegetables is important for food and consumer safety. The aim of this research was to assess the effects of gaseous chlorine dioxide(ClO2)and biocontrol microorganisms (Pseudomonas chlororaphis and P. fluoresc...

  16. 小丑火棘秋冬转色期叶色变化的生理特性%Physiological Characters of Pyracantha fortuneana ‘Harlequin' Leaves During Color-Changing Period in Autumn and Winter

    Institute of Scientific and Technical Information of China (English)

    李向茂

    2013-01-01

    Pyracantha fortuneana ‘ Harlequin' was used to study the year-round changing in leave color and the physiological-biochemical characteristic during color-changing period.The results showed that the leaves of Pyracantha fortuneana ‘Harlequin' changed to red when the mean daily temperature was 15 ℃.The red leaves ornamental period would last from late November to late February of next year.During color-changing period,the content of photosynthetic pigment was decreased,while the content of anthocyan was increased and the largest content was observed at stage Ⅲ with a 26-fold increase compared with stage Ⅰ.The pH value was decreased from 7 at stage 1 to 5 at stage Ⅲ along with the color-changing process.The content of soluble sugar was increased and the largest content was present at stage Ⅳ with a 2.1-fold increased compared with stage Ⅱ.Water content of leaves decreased gradually.A significant difference in content and changing trend in mineral element was observed among different stages.The result of correlation analysis suggested the relationship in various factors,revealing the cooperativity of various factors and the complexity during the color-changing process in plant leaves.%以1年中不同生长期小丑火棘为研究对象,记录小丑火棘叶色的周年表型变化,研究变色过程中的生理生化特性.结果表明,在日平均温度15℃左右小丑火棘叶色开始向红色转变,其红叶观赏期从11月下旬至翌年2月下旬;在变色过程中,小丑火棘叶片中的光合色素含量逐渐降低;花色素苷含量逐渐增加,变色中期的叶片花色素苷含量为花叶期的26倍;pH值则随叶色变红而逐渐降低,由花叶期的7降至红叶期的5;可溶性糖含量逐渐增加,变色终期为变色初期的2.1倍;叶片含水量逐渐降低.不同矿质元素在不同叶色阶段的含量有着明显差异,变化趋势也不尽相同.相关性分析表明,不同生理指标之间存在着一定的

  17. Biocontrol ability and putative mode of action of yeasts against Geotrichum citri-aurantii in citrus fruit.

    Science.gov (United States)

    Ferraz, Luriany Pompeo; Cunha, Tatiane da; da Silva, Aline Caroline; Kupper, Katia Cristina

    2016-01-01

    Sour rot is a major postharvest disease of citrus fruit and is caused by the fungal pathogen Geotrichum citri-aurantii. A lack of chemicals certified for the control of this disease has led to the consideration of alternative methods and strategies, such as the use of yeasts as biocontrol agents. The purpose of the present study was to test the ability of yeasts isolated from leaves, flowers, fruit, and soil, and six Saccharomyces cerevisiae isolates to control citrus sour rot, to assess the mechanisms of action of the yeast isolates that were demonstrated to be effective for biocontrol, and to identify the most effective yeast isolates for the biocontrol of G. citri-aurantii. In in vivo assays, three yeast isolates (ACBL-23, ACBL-44, and ACBL-77) showed a potential for controlling sour rot in citrus fruits, both preventatively and curatively. Most of the eight yeast isolates that were assessed for a mechanism of action did not produce antifungal compounds in an amount sufficient to inhibit the growth of the pathogen. Additionally, nutrient competition among the yeast strains was not found to be a biocontrol strategy. Instead, killer activity and hydrolytic enzyme production were identified as the major mechanisms involved in the biocontrol activity of the yeasts. Isolates ACBL-23, ACBL-44, and ACBL-77, which controlled sour rot most effectively, were identified as Rhodotorula minuta, Candida azyma, and Aureobasidium pullulans, respectively. To our knowledge, this is the first report of the potential of C. azyma as a biological control agent against a postharvest pathogen and its ability to produce a killer toxin.

  18. Root hairs play a key role in the endophytic colonization of olive roots by Pseudomonas spp. with biocontrol activity.

    Science.gov (United States)

    Prieto, Pilar; Schilirò, Elisabetta; Maldonado-González, María Mercedes; Valderrama, Raquel; Barroso-Albarracín, Juan Bautista; Mercado-Blanco, Jesús

    2011-08-01

    The use of indigenous bacterial root endophytes with biocontrol activity against soil-borne phytopathogens is an environmentally-friendly and ecologically-efficient action within an integrated disease management framework. The earliest steps of olive root colonization by Pseudomonas fluorescens PICF7 and Pseudomonas putida PICP2, effective biocontrol agents (BCAs) against Verticillium wilt of olive (Olea europaea L.) caused by the fungus Verticillium dahliae Kleb., are here described. A gnotobiotic study system using in vitro propagated olive plants, differential fluorescent-protein tagging of bacteria, and confocal laser scanning microscopy analysis have been successfully used to examine olive roots-Pseudomonas spp. interactions at the single-cell level. In vivo simultaneous visualization of PICF7 and PICP2 cells on/in root tissues enabled to discard competition between the two bacterial strains during root colonization. Results demonstrated that both BCAs are able to endophytically colonized olive root tissues. Moreover, results suggest a pivotal role of root hairs in root colonization by both biocontrol Pseudomonas spp. However, colonization of root hairs appeared to be a highly specific event, and only a very low number of root hairs were effectively colonized by introduced bacteria. Strains PICF7 and PICP2 can simultaneously colonize the same root hair, demonstrating that early colonization of a given root hair by one strain did not hinder subsequent attachment and penetration by the other. Since many environmental factors can affect the number, anatomy, development, and physiology of root hairs, colonization competence and biocontrol effectiveness of BCAs may be greatly influenced by root hair's fitness. Finally, the in vitro study system here reported has shown to be a suitable tool to investigate colonization processes of woody plant roots by microorganisms with biocontrol potential.

  19. Antifungal Activity of Isolated Bacillus amyloliquefaciens SYBC H47 for the Biocontrol of Peach Gummosis.

    Science.gov (United States)

    Li, Xunhang; Zhang, Yanzhou; Wei, Zhiwen; Guan, Zhengbing; Cai, Yujie; Liao, Xiangru

    2016-01-01

    The gummosis disease is caused by Botryosphaeria dothidea (Moug. ex. Fr) Ces. et de Not., and it is one of the most important diseases of stone fruits worldwide. The use of biocontrol as an alternative approach to synthetic chemical fungicides has aroused general concern about how to control plant diseases that are caused by phytopathogens. The aim of this study is to isolate Bacillus strains from raw honeys with the capacity to inhibit B. dothidea and to explore the mechanisms by which they could be used in the biocontrol of peach gummosis. Bacillus amyloliquefaciens SYBC H47 was isolated and identified on the basis of its physiological and biochemical characteristics and its 16S rRNA and gyrB gene sequences. The cell suspension and the cell-free supernatant of its culture showed significant antifungal activity against Aspergillus niger, Mucor racemosus, Fusarium oxysporum, Penicillium citrinum, and Candida albicans by agar-diffusion assays. The primary antifungal substances were bacillomycin L, fengycin, and surfactin, which were analyzed by HPLC LC/ESI-MS/MS. Bacillomycin L showed the best inhibitory effect against conidial germination of B. dothidea, followed by fengycin and surfactin. Surfactin had limited effects on mycelial growth, contrary to those of bacillomycin L and fengycin. However, a mixture of the three lipopeptides had a synergistic effect that disrupted the structure of the conidia and mycelia. In order to reduce the production cost, the use of waste frying peanut oil and soy oil as the sole carbon source increased the lipopeptide yield levels by approximately 17% (2.42 g/L) and 110% (4.35 g/L), respectively. In a field trial, the decreases in the infected gummosis rate (IGR) and the disease severity index (DSI) through cell suspension treatments were 20% and 57.5% (in 2014), respectively, and 40% and 57.5% (in 2015), respectively, in comparison with the control. In conclusion, B. amyloliquefaciens SYBC H47 could inhibit the germination of conidia

  20. Antifungal Activity of Isolated Bacillus amyloliquefaciens SYBC H47 for the Biocontrol of Peach Gummosis

    Science.gov (United States)

    Zhang, Yanzhou; Wei, Zhiwen; Guan, Zhengbing; Cai, Yujie; Liao, Xiangru

    2016-01-01

    The gummosis disease is caused by Botryosphaeria dothidea (Moug. ex. Fr) Ces. et de Not., and it is one of the most important diseases of stone fruits worldwide. The use of biocontrol as an alternative approach to synthetic chemical fungicides has aroused general concern about how to control plant diseases that are caused by phytopathogens. The aim of this study is to isolate Bacillus strains from raw honeys with the capacity to inhibit B. dothidea and to explore the mechanisms by which they could be used in the biocontrol of peach gummosis. Bacillus amyloliquefaciens SYBC H47 was isolated and identified on the basis of its physiological and biochemical characteristics and its 16S rRNA and gyrB gene sequences. The cell suspension and the cell-free supernatant of its culture showed significant antifungal activity against Aspergillus niger, Mucor racemosus, Fusarium oxysporum, Penicillium citrinum, and Candida albicans by agar-diffusion assays. The primary antifungal substances were bacillomycin L, fengycin, and surfactin, which were analyzed by HPLC LC/ESI-MS/MS. Bacillomycin L showed the best inhibitory effect against conidial germination of B. dothidea, followed by fengycin and surfactin. Surfactin had limited effects on mycelial growth, contrary to those of bacillomycin L and fengycin. However, a mixture of the three lipopeptides had a synergistic effect that disrupted the structure of the conidia and mycelia. In order to reduce the production cost, the use of waste frying peanut oil and soy oil as the sole carbon source increased the lipopeptide yield levels by approximately 17% (2.42 g/L) and 110% (4.35 g/L), respectively. In a field trial, the decreases in the infected gummosis rate (IGR) and the disease severity index (DSI) through cell suspension treatments were 20% and 57.5% (in 2014), respectively, and 40% and 57.5% (in 2015), respectively, in comparison with the control. In conclusion, B. amyloliquefaciens SYBC H47 could inhibit the germination of conidia

  1. Isolation and identification of biocontrol agent Streptomyces rimosus M527 against Fusarium oxysporum f. sp. cucumerinum.

    Science.gov (United States)

    Lu, Dandan; Ma, Zheng; Xu, Xianhao; Yu, Xiaoping

    2016-08-01

    Actinomycetes have received considerable attention as biocontrol agents against fungal plant pathogens and as plant growth promoters. In this study, a total of 320 actinomycetes were isolated from various habitats in China. Among which, 77 strains have been identified as antagonistic activities against Fusarium oxysporum f. sp. cucumerinum which usually caused fusarium wilt of cucumber. Of these, isolate actinomycete M527 not only displayed broad-spectrum antifungal activity but also showed the strongest antagonistic activity against the spore germination of F. oxysporum f. sp. cucumerinum. In pot experiments, the results indicated that isolate M527 could promote the shoot growth and prevent the development of the disease on cucumber caused by F. oxysporum f. sp. cucumerinum. The control efficacy against seedling fusarium wilt of cucumber after M527 fermentation broth root-irrigation was up to 72.1% as compared to control. Based on 16S rDNA sequence analysis, the isolate M527 was identified as Streptomyces rimosus.

  2. Biocontrol efficacy of Cestrum diurnum L. (Solanaceae: Solanales) against the larval forms of Anopheles stephensi.

    Science.gov (United States)

    Ghosh, Anupam; Chandra, Goutam

    2006-04-01

    Cestrum diurnum L. (Solanaceae: Solanales) is a multistemmed shrub that is also known as 'Day Jasmine'. The efficacy of the plant as a strong biocontrol agent of the larval anopheline mosquito was evaluated in the laboratory and bioactive ingredients were characterized by thin layer chromatography (TLC) and infrared (IR) analysis. Thin layer chromatographic analysis revealed the presence of steroidal compound as a bioactive ingredient and IR analysis reported the presence of O-H group, C-S bond as a -CH2S group, H bonded -C=O group and carbonyl stress of esters. The LC50 value of the active ingredient was determined as 0.70, 0.89, 0.90 and 1.03 mg/100 mL-1, for 1st, 2nd, 3rd and 4th instar larva respectively in 24 h study period. The active component was analyzed by GLC and GLC-MS and altogether 14 components were detected.

  3. Isolation and identification of actinomycetes from a compost-amended soil with potential as biocontrol agents.

    Science.gov (United States)

    Cuesta, Gonzalo; García-de-la-Fuente, Rosana; Abad, Manuel; Fornes, Fernando

    2012-03-01

    The search for new biocontrol strategies to inhibit the growth of phytopathogenic microorganisms has become widely widespread due to environmental concerns. Among actinomycetes, Streptomyces species have been extensively studied since they have been recognized as important sources of antibiotics. Actinomycete strains were isolated from a calcareous soil, 2 two-phase olive mill waste ('alperujo') composts, and the compost-amended soil by using selective media, and they were then co-cultured with 5 phytopathogenic fungi and 1 bacterium to perform an in vitro antagonism assay. Forty-nine actinomycete strains were isolated, 12 of them showing a great antagonistic activity towards the phytopathogenic microorganisms tested. Isolated strains were identified by 16S rDNA sequence analysis and phenotypic procedures. Eleven isolates concerned the genus Streptomyces and 1 actinomycete with chitinolytic activity belonged to the genus Lechevalieria.

  4. Native isolate of Trichoderma: a biocontrol agent with unique stress tolerance properties.

    Science.gov (United States)

    Mishra, N; Khan, S S; Sundari, S Krishna

    2016-08-01

    Species of Trichoderma are widely recognized for their biocontrol abilities, but seldom studied collectively, for their plant growth promotion, abiotic stress tolerance and bioremediation properties. Our study is a concentrated effort to establish the potential of native isolate Trichoderma harzianum KSNM (T103) to tolerate biotic (root pathogens) and abiotic stresses [high salt (100-1000 mM); heavy metal (chromium, nickel and zinc: 1-10 mM); pesticides: malathion (100-600 ppm), carbofuran (100-600 ppb)], along with its ability to support plant growth. In vitro growth promotion assays with T103 treated Vigna radiata, Vigna mungo and Hordeum vulgare confirmed 'non-species specific' growth promotion effects of T103. At lower metal concentration, T103 treatment was found to completely negate the impact of metal stress [60 % increase in radicle length (RL) with no significant decrease in %germination (%G)]. Even at 10 mM metal, T103 inoculation gave 80 % increase in %G and >50 % increase in RL. In vitro experiments confirmed high metal reduction capacity (47 %-Cr, 35 %-Ni and 42 %-Zn) of T103 at concentrations as high as 4 mM. At maximum residual concentrations of malathion (440 ppm) and carbofuran (100 ppb) reported in agricultural soils, T103 maintained 80 and 100 % survivability, respectively. T103 treatment has improved %G and RL in all three hosts challenged with pesticide. Isolate T103 was found to effectively suppress growth of three major root pathogens: Macrophomina phaseolina (65.83 %) followed by Sclerotium rolfsii (19.33 %) and Fusarium oxysporum (19.18 %). In the light of these observations, native T. harzianum (T103) seems to be a competent biocontrol agent for tropical agricultural soils contaminated with residual pesticides and heavy metals.

  5. Biocontrol of geosmin-producing Streptomyces spp. by two Bacillus strains from Chinese liquor.

    Science.gov (United States)

    Zhi, Yan; Wu, Qun; Du, Hai; Xu, Yan

    2016-08-16

    Streptomyces spp. producing geosmin have been regarded as the most frequent and serious microbial contamination causing earthy off-flavor in Chinese liquor. It is therefore necessary to control the Streptomyces community during liquor fermentation. Biological control, using the native microbiota present in liquor making, appears to be a better solution than chemical methods. The objective of this study was to isolate native microbiota antagonistic toward Streptomyces spp. and then to evaluate the possible action mode of the antagonists. Fourteen Bacillus strains isolated from different Daqu (the fermentation starter) showed antagonistic activity against Streptomyces sampsonii, which is one of the dominant geosmin producers. Bacillus subtilis 2-16 and Bacillus amyloliquefaciens 1-45 from Maotai Daqu significantly inhibited the growth of S. sampsonii by 57.8% and 84.3% respectively, and effectively prevented the geosmin production in the simulated fermentation experiments (inoculation ratio 1:1). To probe the biocontrol mode, the ability of strain 2-16 and 1-45 to produce antimicrobial metabolites and to reduce geosmin in the fermentation system was investigated. Antimicrobial substances were identified as lipopeptides by ultra-performance liquid chromatography tandem electrospray ionization/quadrupole-time-of-flight mass spectrometry (UPLC-ESI/Q-TOF MS) and in vitro antibiotic assay. In addition, strains 2-16 and 1-45 were able to remove 45% and 15% of the geosmin respectively in the simulated solid-state fermentation. This study highlighted the potential of biocontrol, and how the use of native Bacillus species in Daqu could provide an eco-friendly method to prevent growth of Streptomyces spp. and geosmin contamination in Chinese liquor fermentation.

  6. Cell wall degrading isoenzyme profiles of Trichoderma biocontrol strains show correlation with rDNA species

    Institute of Scientific and Technical Information of China (English)

    Sanz L; Hermosa M R; González F J; Monte E

    2004-01-01

    @@ Species of the fungus Trichoderma, a genus of Hyphomycetes, are ubiquitous in the environment, but especially in soil. They have been used in a wide range of commercial applications including the production of hydrolases and in the biological control of plant diseases. A fundamental part of the Trichoderma antifungal system consists of a series of genes coding for a surprising variety of extracellular cell wall degrading enzymes (CWDE).Characterisation and identification of strains at the species level is the first step in utilizing the full potential of fungi in specific applications. One aim when isolating Trichoderma strains is to identify those which can be used in new agricultural and industrial applications. In the past it was not uncommon that biocontrol strains were defined as T. harzianum Rifai, due to the limited classification system of the genus Trichoderma. In recent years, several PCR-based molecular techniques have been used to detect and discriminate among microorganisms. Sequence analysis of the ITS regions of the ribosomal DNA and gene fragments as those corresponding to tef1 gene have been helpful in the neotypification, description and characterization of species in the genus Trichoderna.Another useful method for the identification of Trichoderma strains is the randomly amplified polymorphic DNA (RAPD) technique.Isozyme polymorphisms evaluation of five putative extracellular lytic enzymes loci (β-1,3-glucanase, β-1,6-glucanase, cellulase, chitinase and protease antivities) were carried out using representative strains of defined molecular groups. CWDE groupings obtained from biocontrol strains are discussed in relation to their phylogenetic location and antifungal activities.Compiling morphological, biochemical and sequence information data into a common database would provide a useful resource that could be used to accurately name new haplotypes identified in the future and correctly place them within the genus Trichoderma.

  7. Interactions between conventional and organic farming for biocontrol services across the landscape.

    Science.gov (United States)

    Bianchi, F J J A; Ives, A R; Schellhorn, N A

    2013-10-01

    While the area of organic crop production increases at a global scale, the potential interactions between pest management in organic and conventionally managed systems have so far received little attention. Here, we evaluate the landscape-level codependence of insecticide-based and natural enemy-based pest management using a simulation model for parasitoid-host interactions in landscapes consisting of conventionally and organically managed fields. In our simulations conventional management consists of broad-spectrum or selective insecticide application, while organic management involves no insecticides. Simulations indicate that insecticide use can easily result in lose-lose scenarios whereby both organically and conventionally managed fields suffer from increased pest loads as compared to a scenario where no insecticides are used, but that under some conditions insecticide use can be compatible with biocontrol. Simulations also suggest that the pathway to achieve the insecticide reduction without triggering additional pest pressure is not straightforward, because increasing the proportion of organically managed fields or reducing the spray frequency in conventional fields can potentially give rise to dramatic increases in pest load. The disruptive effect of insecticide use, however, can be mitigated by spatially clustering organic fields and using selective insecticides, although the effectiveness of this mitigation depends on the behavioral traits of the biocontrol agents. Poorly dispersing parasitoids and parasitoids with high attack rates required a lower amount of organically managed fields for effective pest suppression. Our findings show that the transition from a landscape dominated by conventionally managed crops to organic management has potential pitfalls; intermediate levels of organic management may lead to higher pest burdens than either low or high adoption of organic management.

  8. Genome Sequencing and Comparative Analysis of the Biocontrol Agent Trichoderma harzianum sensu stricto TR274

    Energy Technology Data Exchange (ETDEWEB)

    Steindorff, Andrei S.; Noronha, Elilane F.; Ulhoa, Cirano J.; Kuo, Alan; Salamov, Asaf A.; Haridas, Sajeet; Riley, Robert W.; Druzhinina, Irina S.; Kubicek, Christian P.; Grigoriev, Igor V.

    2015-03-17

    Biological control is a complex process which requires many mechanisms and a high diversity of biochemical pathways. The species of Trichoderma harzianum are well known for their biocontrol activity against many plant pathogens. To gain new insights into the biocontrol mechanism used by T. harzianum, we sequenced the isolate TR274 genome using Illumina. The assembly was performed using AllPaths-LG with a maximum coverage of 100x. The assembly resulted in 2282 contigs with a N50 of 37033bp. The genome size generated was 40.8 Mb and the GC content was 47.7%, similar to other Trichoderma genomes. Using the JGI Annotation Pipeline we predicted 13,932 genes with a high transcriptome support. CEGMA tests suggested 100% genome completeness and 97.9% of RNA-SEQ reads were mapped to the genome. The phylogenetic comparison using orthologous proteins with all Trichoderma genomes sequenced at JGI, corroborates the Trichoderma (T. asperellum and T. atroviride), Longibrachiatum (T. reesei and T. longibrachiatum) and Pachibasium (T. harzianum and T. virens) section division described previously. The comparison between two Trichoderma harzianum species suggests a high genome similarity but some strain-specific expansions. Analyses of the secondary metabolites, CAZymes, transporters, proteases, transcription factors were performed. The Pachybasium section expanded virtually all categories analyzed compared with the other sections, specially Longibrachiatum section, that shows a clear contraction. These results suggests that these proteins families have an important role in their respective phenotypes. Future analysis will improve the understanding of this complex genus and give some insights about its lifestyle and the interactions with the environment.

  9. The importance of chorismate mutase in the biocontrol potential of Trichoderma parareesei

    Directory of Open Access Journals (Sweden)

    Esclaudys ePérez

    2015-10-01

    Full Text Available Species of Trichoderma exert direct biocontrol activity against soil-borne plant pathogens due to their ability to compete for nutrients and to inhibit or kill their targets through the production of antibiotics and/or hydrolytic enzymes. In addition to these abilities, Trichoderma spp. have beneficial effects for plants, including the stimulation of defenses and the promotion of growth. Here we study the role in biocontrol of the T. parareesei Tparo7 gene, encoding a chorismate mutase (CM, a shikimate pathway branch point leading to the production of aromatic amino acids, which are not only essential components of protein synthesis but also the precursors of a wide range of secondary metabolites. We isolated T. parareesei transformants with the Tparo7 gene silenced. Compared with the wild-type, decreased levels of Tparo7 expression in the silenced transformants were accompanied by reduced CM activity, lower growth rates on different culture media, and reduced mycoparasitic behavior against the phytopathogenic fungi Rhizoctonia solani, Fusarium oxysporum and Botrytis cinerea in dual cultures. By contrast, higher amounts of the aromatic metabolites tyrosol, 2-phenylethanol and salicylic acid were detected in supernatants from the silenced transformants, which were able to inhibit the growth of F. oxysporum and B. cinerea. In in vitro plant assays, Tparo7-silenced transformants also showed a reduced capacity to colonize tomato roots. The effect of Tparo7-silencing on tomato plant responses was examined in greenhouse assays. The growth of plants colonized by the silenced transformants was reduced and the plants exhibited an increased susceptibility to B. cinerea in comparison with the responses observed for control plants. In addition, the plants turned yellowish and were defective in jasmonic acid- and ethylene-regulated signaling pathways which was seen by expression analysis of lipoxygenase 1 (LOX1, ethylene-insensitive protein 2 (EIN2 and

  10. Biocontrole de Listeria monocytogenes por Pediococcus acidilactici em couve minimamente processada Biocontrol of Listeria monocytogenes by Pediococcus acidilactici in fresh-cut kale

    Directory of Open Access Journals (Sweden)

    Wanessa Altimiras Costa

    2009-12-01

    Full Text Available Este estudo avaliou um sistema de biocontrole para inibição de Listeria monocytogenes em couve minimamente processada, objetivando sua segurança durante estocagem sob refrigeração e em condições de abuso de temperatura. O potencial inibitório de bactérias láticas tolerantes ao sal e psicrotróficas contaminantes naturais da couve e Lactobacillus plantarum, Lactobacillus delbrueckii ATCC 9649 e Lactobacillus casei CCT 1465 foram avaliadas contra L. monocytogenes. O isolado de couve identificado como P. acidilactici CCA3 inibiu L. monocytogenes a 10 e 15 °C em ágar MRS e foi selecionado como possível agente de biocontrole. O número de L. monocytogenes na couve minimamente processada aumentou 3,7 e 4,7 ciclos logarítmicos a 5 e 10 °C, respectivamente, após 20 dias de armazenamento e 4,6 ciclos logarítmicos após oito dias a 15 °C. Entretanto, quando 10(8 UFC.g-1 de P. acidilactici CCA3 foram inoculados no produto processado, o crescimento de L. monocytogenes reduziu 2,3 ciclos logarítmicos sob temperatura abusiva de 15 °C. A acidez titulável e as características sensoriais da couve não foram alteradas pela presença de CCA3 ao longo do período de vida útil. Estes resultados sugerem o potencial de aplicação dos bioconservantes na couve minimamente processada, que necessitam estar associados à refrigeração e sanitização para garantir segurança.This study evaluated a biological control system for the inhibition of Listeria monocytogenes in minimally processed kale focusing on its freshness under refrigeration and extreme temperatures. The inhibitory potential of salt and cold tolerant lactic bacteria from natural microflora of kale, Lactobacillus delbrueckii ATCC 9649, Lactobacillus plantarum, and Lactobacillus casei CCT 1465 strains were evaluated against L. monocytogenes. Pediococcus acidilactici CCA3 isolated from kale exhibited a large inhibition zone of L. monocytogenes at 10 and 15 °C in MRS agar and was

  11. Effect of rice husbandry on mosquito breeding at Mwea Rice Irrigation Scheme with reference to biocontrol strategies.

    Science.gov (United States)

    Asimeng, E J; Mutinga, M J

    1993-03-01

    A study was carried out at Mwea Rice Irrigation Scheme, Kenya, to assess the impact of rice husbandry on mosquito breeding and identify indigenous biocontrol agents with potential for controlling mosquito breeding in the scheme. The study established a close relationship between the schedule of the farming practices (particularly the flooding phase) and mosquito breeding. Two groups of agents, entomopathogenic bacteria (Bacillus thuringiensis var. israelensis) and larvivorous fish, were identified. Laboratory evaluation of the agents produced encouraging results. The bacterial isolates showed broad-spectrum larvicidal potency against Anopheles, Culex and Aedes mosquito larvae and 2 of the fish species, Tilapia zilli and Oreochromis niloticus, demonstrated a strong predation for a mosquito larval diet. To facilitate their use in effective biocontrol strategies, the agents would require further evaluation under field conditions.

  12. Antimicrobial Activity of Bacillus sp. Natural Isolates and Their Potential Use in the Biocontrol of Phytopathogenic Bacteria

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    Tanja Berić

    2012-01-01

    Full Text Available Screening of 203 Bacillus sp. natural isolates for antimicrobial activity against phytopathogenic bacteria showed that 127 tested strains inhibit at least one sensitive strain, which illustrates their potential use as biocontrol agents. Among them, 104 isolates showed significant antagonism against Xanthomonas oryzae pv. oryzae, and only one of these (VPS50.2 synthesizes bacteriocin. An additional screening tested whether 51 isolates contained genes involved in the biosynthesis of lipopeptides of the iturin and surfactin classes. Results show that 33 isolates harbour the operon for iturin biosynthesis, and six of them carry the sfp gene, responsible for the biosynthesis of surfactin. Lipopeptide purification from the supernatant of isolate SS12.9 (identified as B. subtilis or B. amyloliquefaciens was performed using ethyl acetate extraction, ultrafiltration and reversed phase HPLC. Mass spectrometry analysis confirmed that isolate SS12.9 produces a substance of the iturin class with potential for biocontrol of X. oryzae pv. oryzae.

  13. Differential host-finding abilities by a weed biocontrol insect create within-patch spatial refuges for nontarget plants.

    Science.gov (United States)

    Catton, Haley A; Lalonde, Robert G; De Clerck-Floate, Rosemarie A

    2014-10-01

    Many modern weed biocontrol insects exhibit transient "spillover" nontarget herbivory when and where insects are in high density, such as following biocontrol releases, or around dense target weed infestations. Understanding spatial patterns of herbivory is important for predicting efficacy and safety of biocontrol, as refuges from herbivory can buffer plants from population-level impacts. Here, we demonstrate that differential host-finding and arrestment behaviors by an oligophagous biocontrol insect lead to spatial refuges from nontarget herbivory around insect release points within mixed patches of target and nontarget plants. We created transient insect outbreaks by releasing large numbers of Mogulones crucifer Pallas (Coleoptera: Curculionidae) into naturally occurring rangeland patches of the nontarget plant Hackelia micrantha (Eastwood) J.L. Gentry with varying densities of its target weed Cynoglossum officinale L., and monitored spatial patterns of herbivory around release points after 4-7 wk. In complement, we conducted a mark-release-recapture (MRR) experiment to compare M. crucifer's target and nontarget host-finding and arrestment behaviors. For rangeland releases, 95% of nontarget herbivory occurred within 4.25 m of release points, independent of target plant density. Target herbivory occurred throughout our evaluation radii (up to 14 m), where maximum density of diffusing M. crucifer was 1/10 of that in the nontarget herbivory radius. In the MRR experiment, more weevils were recaptured on C. officinale (but not H. micrantha) than expected by chance. M. crucifer's lack of specialized nontarget host-finding and arrestment behaviors means that spatial refuges from herbivory are created for H. micrantha just meters away from sources of high weevil density.

  14. Evidence for Biotrophic Lifestyle and Biocontrol Potential of Dark Septate Endophyte Harpophora oryzae to Rice Blast Disease

    OpenAIRE

    Zhen-Zhu Su; Li-Juan Mao; Na Li; Xiao-Xiao Feng; Zhi-Lin Yuan; Li-Wei Wang; Fu-Cheng Lin; Chu-Long Zhang

    2013-01-01

    The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the e...

  15. Arbuscular Mycorrhizal Fungi for the Biocontrol of Plant-Parasitic Nematodes: A Review of the Mechanisms Involved.

    Science.gov (United States)

    Schouteden, Nele; De Waele, Dirk; Panis, Bart; Vos, Christine M

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate root symbionts that can protect their host plant against biotic stress factors such as plant-parasitic nematode (PPN) infection. PPN consist of a wide range of species with different life styles that can cause major damage in many important crops worldwide. Various mechanisms have been proposed to play a role in the biocontrol effect of AMF against PPN. This review presents an overview of the different mechanisms that have been proposed, and discusses into more detail the plausibility of their involvement in the biocontrol against PPN specifically. The proposed mechanisms include enhanced plant tolerance, direct competition for nutrients and space, induced systemic resistance (ISR) and altered rhizosphere interactions. Recent studies have emphasized the importance of ISR in biocontrol and are increasingly placing rhizosphere effects on the foreground as well, both of which will be the focal point of this review. Though AMF are not yet widely used in conventional agriculture, recent data help to develop a better insight into the modes of action, which will eventually lead toward future field applications of AMF against PPN. The scientific community has entered an exciting era that provides the tools to actually unravel the underlying molecular mechanisms, making this a timely opportunity for a review of our current knowledge and the challenges ahead.

  16. Augmentative biocontrol in natural marine habitats: persistence, spread and non-target effects of the sea urchin Evechinus chloroticus.

    Directory of Open Access Journals (Sweden)

    Javier Atalah

    Full Text Available Augmentative biocontrol aims to control established pest populations through enhancement of their indigenous enemies. To our knowledge, this approach has not been applied at an operational scale in natural marine habitats, in part because of the perceived risk of adverse non-target effects on native ecosystems. In this paper, we focus on the persistence, spread and non-target effects of the sea urchin Evechinus chloroticus when used as biocontrol agent to eradicate an invasive kelp from Fiordland, New Zealand. Rocky reef macrobenthic assemblages were monitored over 17 months in areas where the indigenous algal canopy was either removed or left intact prior to the translocation of a large number of urchins (>50 ind.·m(-2. Urchin densities in treated areas significantly declined ∼9 months after transplant, and began spreading to adjacent sites. At the end of the 17-month study, densities had declined to ∼5 ind.·m(-2. Compared to controls, treatment sites showed persistent shifts from kelp forest to urchin barrens, which were accompanied by significant reductions in taxa richness. Although these non-target effects were pronounced, they were considered to be localised and reversible, and arguably outweigh the irreversible and more profound ecological impacts associated with the establishment of an invasive species in a region of high conservation value. Augmentative biocontrol, used in conjunction with traditional control methods, represents a promising tool for the integrated management of marine pests.

  17. Rhodococcus erythropolis and Its γ-Lactone Catabolic Pathway: An Unusual Biocontrol System That Disrupts Pathogen Quorum Sensing Communication

    Directory of Open Access Journals (Sweden)

    Xavier Latour

    2013-12-01

    Full Text Available Rhodococcus erythropolis is an environmental Gram-positive Actinobacterium with a versatile metabolism involved in various bioconversions and degradations. Rhodococci are best known for their great potential in numerous decontamination and industrial processes. However, they can also prevent plant disease by disrupting quorum sensing-based communication of Gram-negative soft-rot bacteria, by degrading N-acyl-homoserine lactone signaling molecules. Such biocontrol activity results partly from the action of the γ-lactone catabolic pathway. This pathway is responsible for cleaving the lactone bond of a wide range of compounds comprising a γ-butyrolactone ring coupled to an alkyl or acyl chain. The aliphatic products of this hydrolysis are then activated and enter fatty acid metabolism. This short pathway is controlled by the presence of the γ-lactone, presumably sensed by a TetR-like transcriptional regulator, rather than the presence of the pathogen or the plant-host in the environment of the Rhodococci. Both the density and biocontrol activity of R. erythropolis may be boosted in crop systems. Treatment with a cheap γ-lactone stimulator, for example, the food flavoring γ-caprolactone, induces the activity in the biocontrol agent, R. erythropolis, of the pathway degrading signaling molecules; such treatments thus promote plant protection.

  18. Augmentative biocontrol in natural marine habitats: persistence, spread and non-target effects of the sea urchin Evechinus chloroticus.

    Science.gov (United States)

    Atalah, Javier; Hopkins, Grant A; Forrest, Barrie M

    2013-01-01

    Augmentative biocontrol aims to control established pest populations through enhancement of their indigenous enemies. To our knowledge, this approach has not been applied at an operational scale in natural marine habitats, in part because of the perceived risk of adverse non-target effects on native ecosystems. In this paper, we focus on the persistence, spread and non-target effects of the sea urchin Evechinus chloroticus when used as biocontrol agent to eradicate an invasive kelp from Fiordland, New Zealand. Rocky reef macrobenthic assemblages were monitored over 17 months in areas where the indigenous algal canopy was either removed or left intact prior to the translocation of a large number of urchins (>50 ind.·m(-2)). Urchin densities in treated areas significantly declined ∼9 months after transplant, and began spreading to adjacent sites. At the end of the 17-month study, densities had declined to ∼5 ind.·m(-2). Compared to controls, treatment sites showed persistent shifts from kelp forest to urchin barrens, which were accompanied by significant reductions in taxa richness. Although these non-target effects were pronounced, they were considered to be localised and reversible, and arguably outweigh the irreversible and more profound ecological impacts associated with the establishment of an invasive species in a region of high conservation value. Augmentative biocontrol, used in conjunction with traditional control methods, represents a promising tool for the integrated management of marine pests.

  19. Integrated effect of gamma radiation and biocontrol agent on quality parameters of apple fruit: An innovative commercial preservation method

    Science.gov (United States)

    Ahari Mostafavi, Hossein; Mahyar Mirmajlessi, Seyed; Fathollahi, Hadi; Shahbazi, Samira; Mohammad Mirjalili, Seyed

    2013-10-01

    Effects of gamma irradiation and biocontrol agent (Pseudomonas fluorescens) on the physico-chemical parameters (including moisture, total soluble solids, antioxidant activity, phenolic content and firmness) of cv. Golden Delicious apples were investigated for their ability to avoid the post-harvest blue mold caused by Penicillium expansum during cold storage. Freshly harvested apples were inoculated with P. expansum. Treated fruits were irradiated at doses of 0, 200, 400, 600 and 800 Gy and then inoculated with P. fluorescens suspension. Samples were evaluated at 3 month intervals. The results demonstrated a clear link between antioxidant activity and phenolic content, so that dose range of 200-400 Gy significantly increased phenolic content and antioxidant activity. Effect of P. fluorescens was similar to irradiation at 200 and 400 Gy that could prevent lesion diameter in pathogen-treated apples. As dose and storage time increased firmness decreased but, combination of P. fluorescens as well as irradiation (at 200-400 Gy) could decrease softening apple fruits during storage. In all parameters, P. fluorescens (as biocontrol agent) inhibited P. expansum similar to irradiation at 200-400 Gy. So, integrated treatment of irradiation and biocontrol agent explored the potential dual benefit of low doses (200 and 400 Gy) as a suitable method to sustain physico-chemical quality and conclusively reduce apple fruits losses during post-harvest preservation.

  20. ppGpp controlled by the Gac/Rsm regulatory pathway sustains biocontrol activity in Pseudomonas fluorescens CHA0.

    Science.gov (United States)

    Takeuchi, Kasumi; Yamada, Kosumi; Haas, Dieter

    2012-11-01

    In Pseudomonas fluorescens CHA0 and other fluorescent pseudomonads, the Gac/Rsm signal transduction pathway is instrumental for secondary metabolism and biocontrol of root pathogens via the expression of regulatory small RNAs (sRNAs). Furthermore, in strain CHA0, an imbalance in the Krebs cycle can affect the strain's ability to produce extracellular secondary metabolites, including biocontrol factors. Here, we report the metabolome of wild-type CHA0, a gacA-negative mutant, which has lost Gac/Rsm activities, and a retS-negative mutant, which shows strongly enhanced Gac/Rsm-dependent activities. Capillary electrophoresis-based metabolomic profiling revealed that the gacA and retS mutations had opposite effects on the intracellular levels of a number of central metabolites, suggesting that the Gac/Rsm pathway regulates not only secondary metabolism but also primary metabolism in strain CHA0. Among the regulated metabolites identified, the alarmone guanosine tetraphosphate (ppGpp) was characterized in detail by the construction of relA (for ppGpp synthase) and spoT (for ppGpp synthase/hydrolase) deletion mutants. In a relA spoT double mutant, ppGpp synthesis was completely abolished, the expression of Rsm sRNAs was attenuated, and physiological functions such as antibiotic production, root colonization, and plant protection were markedly diminished. Thus, ppGpp appears to be essential for sustaining epiphytic fitness and biocontrol activity of strain CHA0.

  1. Comparative transcriptome analysis of the biocontrol strain Bacillus amyloliquefaciens FZB42 as response to biofilm formation analyzed by RNA sequencing.

    Science.gov (United States)

    Kröber, Magdalena; Verwaaijen, Bart; Wibberg, Daniel; Winkler, Anika; Pühler, Alfred; Schlüter, Andreas

    2016-08-10

    The strain Bacillus amyloliquefaciens FZB42 is a plant growth promoting rhizobacterium (PGPR) and biocontrol agent known to keep infections of lettuce (Lactuca sativa) by the phytopathogen Rhizoctonia solani down. Several mechanisms, including the production of secondary metabolites possessing antimicrobial properties and induction of the host plant's systemic resistance (ISR), were proposed to explain the biocontrol effect of the strain. B. amyloliquefaciens FZB42 is able to form plaques (biofilm-like structures) on plant roots and this feature was discussed to be associated with its biocontrol properties. For this reason, formation of B. amyloliquefaciens biofilms was studied at the transcriptional level using high-throughput sequencing of whole transcriptome cDNA libraries from cells grown under biofilm-forming conditions vs. planktonic growth. Comparison of the transcriptional profiles of B. amyloliquefaciens FZB42 under these growth conditions revealed a common set of highly transcribed genes mostly associated with basic cellular functions. The lci gene, encoding an antimicrobial peptide (AMP), was among the most highly transcribed genes of cells under both growth conditions suggesting that AMP production may contribute to biocontrol. In contrast, gene clusters coding for synthesis of secondary metabolites with antimicrobial properties were only moderately transcribed and not induced in biofilm-forming cells. Differential gene expression revealed that 331 genes were significantly up-regulated and 230 genes were down-regulated in the transcriptome of B. amyloliquefaciens FZB42 under biofilm-forming conditions in comparison to planktonic cells. Among the most highly up-regulated genes, the yvqHI operon, coding for products involved in nisin (class I bacteriocin) resistance, was identified. In addition, an operon whose products play a role in fructosamine metabolism was enhanced in its transcription. Moreover, genes involved in the production of the extracellular

  2. Nontarget herbivory by a weed biocontrol insect is limited to spillover, reducing the chance of population-level impacts.

    Science.gov (United States)

    Catton, Haley A; Lalonde, Robert G; De Clerck-Floate, Rosemarie A

    2015-03-01

    Insects approved for classical biocontrol of weeds are often capable of using close relatives of their target weed for feeding, oviposition, or larval development, with reduced preference and performance. When nontarget herbivory occurs and is suspected to reduce survival, growth, or fecundity of individual plants, and insects are capable of reproducing on their nontarget host, characterization of spatial and temporal patterns of the occurrence and intensity of herbivory is valuable for predicting potential population-level effects. Here, we perform a novel post-release manipulative field experiment with a root-feeding biocontrol weevil, Mogulones crucifer, released in Canada to control the rangeland weed Cynoglossum officinale, to test for its ability to establish on the nontarget plant Hackelia micrantha. After Cynoglossum, M. crucifer exhibits its highest preference for and performance on Hackelia spp. We released M. crucifer on Canadian rangeland sites with naturally occurring populations of H. micrantha growing interspersed with the target weed or in the near absence of the target weed. Adult weevil feeding on surrounding plants was monitored for three summers after release (years 0, 1, and 2), and, subsequently, subsets of plants were destructively sampled to determine M. crucifer oviposition levels. Additional oviposition and larval development data were obtained from seven non-experimental sites where weevils were released zero, three, or four years earlier. M. crucifer was not detected on experimental sites without C. officinale after two years, and nontarget herbivory was restricted to rare, low-level spillover. Visible evidence of adult herbivory (i.e., scars on shoots) was associated with oviposition in 90% of targets but only 30% of nontarget plants. We infer, through ecological refuge theory, that nontarget population-level impacts from M. crucifer spillover are unlikely because of temporal, spatial, and probabilistic refuges from herbivory, and make

  3. The Potential Use of Wolbachia-Based Mosquito Biocontrol Strategies for Japanese Encephalitis.

    Directory of Open Access Journals (Sweden)

    Claire L Jeffries

    Full Text Available Japanese encephalitis virus (JEV is a zoonotic pathogen transmitted by the infectious bite of Culex mosquitoes. The virus causes the development of the disease Japanese encephalitis (JE in a small proportion of those infected, predominantly affecting children in eastern and southern Asia. Annual JE incidence estimates range from 50,000-175,000, with 25%-30% of cases resulting in mortality. It is estimated that 3 billion people live in countries in which JEV is endemic. The virus exists in an enzootic transmission cycle, with mosquitoes transmitting JEV between birds as reservoir hosts and pigs as amplifying hosts. Zoonotic infection occurs as a result of spillover events from the main transmission cycle. The reservoir avian hosts include cattle egrets, pond herons, and other species of water birds belonging to the family Ardeidae. Irrigated rice fields provide an ideal breeding ground for mosquitoes and attract migratory birds, maintaining the transmission of JEV. Although multiple vaccines have been developed for JEV, they are expensive and require multiple doses to maintain efficacy and immunity. As humans are a "dead-end" host for the virus, vaccination of the human population is unlikely to result in eradication. Therefore, vector control of the principal mosquito vector, Culex tritaeniorhynchus, represents a more promising strategy for reducing transmission. Current vector control strategies include intermittent irrigation of rice fields and space spraying of insecticides during outbreaks. However, Cx. Tritaeniorhynchus is subject to heavy exposure to pesticides in rice fields, and as a result, insecticide resistance has developed. In recent years, significant advancements have been made in the potential use of the bacterial endosymbiont Wolbachia for mosquito biocontrol. The successful transinfection of Wolbachia strains from Drosophila flies to Aedes (Stegomyia mosquitoes has resulted in the generation of "dengue-refractory" mosquito

  4. Molecular characterization of alkaline protease of Bacillus amyloliquefaciens SP1 involved in biocontrol of Fusarium oxysporum.

    Science.gov (United States)

    Guleria, Shiwani; Walia, Abhishek; Chauhan, Anjali; Shirkot, C K

    2016-09-02

    An alkaline protease gene was amplified from genomic DNA of Bacillus amyloliquefaciens SP1 which was involved in effective biocontrol of Fusarium oxysporum. We investigated the antagonistic capacity of protease of B. amyloliquifaciens SP1, under in vitro conditions. The 5.62 fold purified enzyme with specific activity of 607.69U/mg reported 24.14% growth inhibition of F. oxysporum. However, no antagonistic activity was found after addition of protease inhibitor i.e. PMSF (15mM) to purified enzyme. An 1149bp nucleotide sequence of protease gene encoded 382 amino acids of 43kDa and calculated isoelectric point of 9.29. Analysis of deduced amino acid sequence revealed high homology (86%) with subtilisin E of Bacillus subtilis. The B. amyloliquefaciens SP1 protease gene was expressed in Escherichiax coli BL21. The expressed protease was secreted into culture medium by E. coli and exhibited optimum activity at pH8.0 and 60°C. The most reliable three dimensional structure of alkaline protease was determined using Phyre 2 server which was validated on the basis of Ramachandran plot and ERRAT value. The expression and structure prediction of the enzyme offers potential value for commercial application in agriculture and industry.

  5. The advantages of mosquito biocontrol by stocking edible fish in rice paddies.

    Science.gov (United States)

    Wu, N; Liao, G H; Li, D F; Luo, Y L; Zhong, G M

    1991-09-01

    Edible fish stocked in rice fields at a density of 600-800 fry per mu (1 mu = 1/15 hectare) for 150-170 days may act as an effective mosquito biocontrol agent. Common carp (Cyprinus carpio), grass carp Ctenopharyngodon idella) and Tilopia spp. killed late stage larvae and pupae of Anopheles sinensis and Culex tritaeniorrhyncus in laboratory and field trials. Stocking of fish in experimental rice fields decreased larval numbers significantly in comparison with control areas. Expansion of fish stocking in rice fields on a large scale over several years correlated with a marked decrease in malaria transmission. The addition of fish to the rice fields also resulted in increased yields. A ditch-ridge system of field arrangements is described for optimization of fish handling. Preliminary cost-benefit analysis indicates that this approach to mosquito control conveys considerable economic advantage and thus provides incentive to the community to participate in vector control programs. Farmers' experience in Guangxi over a number of years indicates that the use of edible fish for this purpose can be carried on a large, commercially viable scale.

  6. Selection rhizosphere-competent microbes for development of microbial products as biocontrol agents

    Science.gov (United States)

    Mashinistova, A. V.; Elchin, A. A.; Gorbunova, N. V.; Muratov, V. S.; Kydralieva, K. A.; Khudaibergenova, B. M.; Shabaev, V. P.; Jorobekova, Sh. J.

    2009-04-01

    Rhizosphere-borne microorganisms reintroduced to the soil-root interface can establish without inducing permanent disturbance in the microbial balance and effectively colonise the rhizosphere due to carbon sources of plant root exudates. A challenge for future development of microbial products for use in agriculture will be selection of rhizosphere-competent microbes that both protect the plant from pathogens and improve crop establishment and persistence. In this study screening, collection, identification and expression of stable and technological microbial strains living in soils and in the rhizosphere of abundant weed - couch-grass Elytrigia repens L. Nevski were conducted. A total of 98 bacteria isolated from the rhizosphere were assessed for biocontrol activity in vitro against phytopathogenic fungi including Fusarium culmorum, Fusarium heterosporum, Fusarium oxysporum, Drechslera teres, Bipolaris sorokiniana, Piricularia oryzae, Botrytis cinerea, Colletothrichum atramentarium and Cladosporium sp., Stagonospora nodorum. Biocontrol activity were performed by the following methods: radial and parallel streaks, "host - pathogen" on the cuts of wheat leaves. A culture collection comprising 64 potential biocontrol agents (BCA) against wheat and barley root diseases has been established. Of these, the most effective were 8 isolates inhibitory to at least 4 out of 5 phytopathogenic fungi tested. The remaining isolates inhibited at least 1 of 5 fungi tested. Growth stimulating activity of proposed rhizobacteria-based preparations was estimated using seedling and vegetative pot techniques. Seeds-inoculation and the tests in laboratory and field conditions were conducted for different agricultural crops - wheat and barley. Intact cells, liquid culture filtrates and crude extracts of the four beneficial bacterial strains isolated from the rhizosphere of weed were studied to stimulate plant growth. As a result, four bacterial strains selected from rhizosphere of weed

  7. Selection and Characterization of Endophytic Bacteria as Biocontrol Agents of Tomato Bacterial Wilt Disease

    Directory of Open Access Journals (Sweden)

    ABDJAD ASIH NAWANGSIH

    2011-06-01

    Full Text Available Biological control of bacterial wilt pathogen (Ralstonia solanacearum of tomato using endophytic bacteria is one of the alternative control methods to support sustainable agriculture. This study was conducted to select and characterize endophytic bacteria isolated from healthy tomato stems and to test their ability to promote plant growth and suppress bacterial wilt disease. Among 49 isolates successfully isolated, 41 were non-plant pathogenic. Green house test on six selected isolates based on antagonistic effect on R. solanacearum or ability to suppress R. solanacearum population in dual culture assays obtained BC4 and BL10 isolates as promising biocontrol agents. At six weeks after transplanting, plants treated with BC4 isolate showed significantly lower disease incidence (33% than that of control (83%. Plants height was not significantly affected by endophytic bacterial treatments. Based on 16S rRNA sequence, BC4 isolate had 97% similarity with Staphylococcus epidermidis (accession number EU834240.1, while isolate BL10 had 98% similarity with Bacillus amyloliquefaciens strain JK-SD002 (accession number AB547229.1.

  8. Conidia production of Beauveria sp. by solid-state fermentation for biocontrol of Ilex paraguariensis caterpillars.

    Science.gov (United States)

    Dalla Santa, H S; Sousa, N J; Brand, D; Dalla Santa, O R; Pandey, A; Sobotka, M; Paca, J; Soccol, C R

    2004-01-01

    Conidia production of Beauveria sp. strain LAG by solid-state fermentation (SSF) using blends of agro-industrial residues (residual potatoes and sugar-cane bagasse) was optimized with respect to cultivation conditions and the composition of substrate mixture in Erlenmeyer flasks and column-type bioreactor. With a blend of 60 % residual potatoes and 40 % sugar-cane bagasse the optimum conditions achieved were: incubation temperature 26 degrees C, initial substrate pH 6, inoculum concentration 10(7) conidia per g substrate; optimal initial moisture of the substrate was 70 % for Erlenmeyer flasks, in column-type bioreactor (with forced aeration) the optimal initial moisture of the substrate was 65 % with airflow of 60 mL/min. The highest production (1.07 x 10(10) conidia per g dry substrate) was achieved after a 10-d fermentation. The conidia were used in laboratory assays against Thelosia camina and Hylesia sp., caterpillars that are serious pests of mate plants. The mortality of T. camina was >90 % 10 d after spraying caterpillars with 1 mL conidia suspension at a concentration 10(5)-10(8)/mL. For Hylesia sp., the mortality was 70 %, 7 d after immersion in the conidia suspension containing 108 conidia per mL. Therefore, the Beauveria sp. LAG can be considered to be an important biocontrol instrument in the prospect of the Integrated Pest Management for mate plants.

  9. POTENCY OF VIBRIO ISOLATES FOR BIOCONTROL OF VIBRIOSIS IN TIGER SHRIMP (PENAEUS MONODON LARVAE

    Directory of Open Access Journals (Sweden)

    B. W. LAY

    2003-01-01

    Full Text Available This study was carried out to obtain Vibrio isolates able to function as biocontr ol of vibriosis in shrimp hatchery. Thirty one Vibrio isolates were isolated from tiger shrimp larvae and hatchery environments, i.e. Labuan, Pangandaran, and Lampung, Indonesia. Pathogenic V. harveyi MR5339 was obtained from Maros, South-Sulawesi and was made as a rifampicin resistant mutant (RFR to screen for those 31 Vibrio isolates in in vitro assays and to allow us to monitor their presence in shrimp larvae and larval rearing water. Almost all Vibrio isolates could inhibit the growth of pathogenic V. harveyi MR5339 RFR. SKT-b isolate from Skeletonema was the most effective to inhibit the growth of V. harveyi MR5339 Rf* and significantly reduced larval mortality in pathogen challenge assays. These prospective biocontrol bacteria, at concentration of 10" CFU/ml, did not show pathogenicity to shrimp larvae. SKT-b was Gram negative, short rod-shape, exhibited yellow colonies on TCBS and swarming on SWC-agar media, motile, u tilized glucose and sucrose but not lactose: produced extra-cellular protease and amylase, but did not produce chitmase. Partial sequencing of 16S-rRNA gene SKT-b showed SKT-b similarity to Vibrio alginofyticus.

  10. Bacterial-Feeding Nematode Growth and Preference for Biocontrol Isolates of the Bacterium Burkholderia cepacia.

    Science.gov (United States)

    Carta, L K

    2000-12-01

    The potential of different bacterial-feeding Rhabditida to consume isolates of Burkholderia cepacia with known agricultural biocontrol ability was examined. Caenorhabditis elegans, Diploscapter sp., Oscheius myriophila, Pelodera strongyloides, Pristionchus pacificus, Zeldia punctata, Panagrellus redivivus, and Distolabrellus veechi were tested for growth on and preference for Escherichia coli OP50 or B. cepacia maize soil isolates J82, BcF, M36, Bc2, and PHQM100. Considerable growth and preference variations occurred between nematode taxa on individual bacterial isolates, and between different bacterial isolates on a given nematode. Populations of Diploscapter sp. and P. redivivus were most strongly suppressed. Only Z. punctata and P. pacificus grew well on all isolates, though Z. punctata preferentially accumulated on all isolates and P. pacificus had no preference. Oscheius myriophila preferentially accumulated on growth-supportive Bc2 and M36, and avoided less supportive J82 and PHQM100. Isolates with plant-parasitic nematicidal properties and poor fungicidal properties supported the best growth of three members of the Rhabditidae, C. elegans, O. myriophila, and P. strongyloides. Distolabrellus veechi avoided commercial nematicide M36 more strongly than fungicide J82.

  11. Native Killer Yeasts as Biocontrol Agents of Postharvest Fungal Diseases in Lemons

    Science.gov (United States)

    Garnica, Nydia Mercedes; Fernández-Zenoff, María Verónica; Farías, María Eugenia; Sepulveda, Milena; Ramallo, Jacqueline; Dib, Julián Rafael

    2016-01-01

    Economic losses caused by postharvest diseases represent one of the main problems of the citrus industry worldwide. The major diseases affecting citrus are the "green mold" and "blue mold", caused by Penicillium digitatum and P. italicum, respectively. To control them, synthetic fungicides are the most commonly used method. However, often the emergence of resistant strains occurs and their use is becoming more restricted because of toxic effects and environmental pollution they generate, combined with trade barriers to international markets. The aim of this work was to isolate indigenous killer yeasts with antagonistic activity against fungal postharvest diseases in lemons, and to determine their control efficiency in in vitro and in vivo assays. Among 437 yeast isolates, 8.5% show to have a killer phenotype. According to molecular identification, based on the 26S rDNA D1/D2 domain sequences analysis, strains were identified belonging to the genera Saccharomyces, Wickerhamomyces, Kazachstania, Pichia, Candida and Clavispora. Killers were challenged with pathogenic molds and strains that caused the maximum in vitro inhibition of P. digitatum were selected for in vivo assays. Two strains of Pichia and one strain of Wickerhamomyces depicted a significant protection (p <0.05) from decay by P. digitatum in assays using wounded lemons. Thus, the native killer yeasts studied in this work showed to be an effective alternative for the biocontrol of postharvest fungal infections of lemons and could be promising agents for the development of commercial products for the biological control industry. PMID:27792761

  12. Experimental evaluation of Odonata nymph in the biocontrol of schistosomiasis intermediate hosts

    Institute of Scientific and Technical Information of China (English)

    Aly Younes; Hanaa El-Sherief; Fathia Gawish; Marwa Mahmoud

    2016-01-01

    Objective: To evaluate the predatory potential of the Odonata nymph on freshwater snails that serve as intermediate hosts for Schistosoma species (Bulinus truncatus and Biomphalaria alexandrina). Methods: Observations on the searching, attacking and devouring of the two snail types with series of laboratory-based predation experiments, whose aims were to determine daily predation rate, differential predation, prey preference considering small-, medium-and large-sized snails were conducted. Results: Laboratory evaluation revealed that, the Odonata nymph could kill and consume the two intermediate hosts. The number of snails consumed differed according to the snail type, size and density. The times taken for searching and handling times were dependent on the snail size, type and satiation of the predator. The predation rate varied also with respect to snail type, size and density. This study also evaluated that Odonata nymphs consumed more Bulinus truncatus than Biomphalaria alexandrina per unit time, and that there may be a preference for smaller than larger snails. Conclusions: According to our observation, the predator, Hemianax ephippiger nymph may be a suitable biocontrol agent in connection with Schistosoma intermediate hosts.

  13. The toolbox of Trichoderma spp. in the biocontrol of Botrytis cinerea disease.

    Science.gov (United States)

    Vos, Christine M F; De Cremer, Kaat; Cammue, Bruno P A; De Coninck, Barbara

    2015-05-01

    Botrytis cinerea is a necrotrophic fungal pathogen causing disease in many plant species, leading to economically important crop losses. So far, fungicides have been widely used to control this pathogen. However, in addition to their detrimental effects on the environment and potential risks for human health, increasing fungicide resistance has been observed in the B. cinerea population. Biological control, that is the application of microbial organisms to reduce disease, has gained importance as an alternative or complementary approach to fungicides. In this respect, the genus Trichoderma constitutes a promising pool of organisms with potential for B. cinerea control. In the first part of this article, we review the specific mechanisms involved in the direct interaction between the two fungi, including mycoparasitism, the production of antimicrobial compounds and enzymes (collectively called antagonism), and competition for nutrients and space. In addition, biocontrol has also been observed when Trichoderma is physically separated from the pathogen, thus implying an indirect systemic plant defence response. Therefore, in the second part, we describe the consecutive steps leading to induced systemic resistance (ISR), starting with the initial Trichoderma-plant interaction and followed by the activation of downstream signal transduction pathways and, ultimately, the defence response resulting in ISR (ISR-prime phase). Finally, we discuss the ISR-boost phase, representing the effect of ISR priming by Trichoderma spp. on plant responses after additional challenge with B. cinerea.

  14. Biocontrol agent Bacillus amyloliquefaciens LJ02 induces systemic resistance against cucurbits powdery mildew.

    Science.gov (United States)

    Li, Yunlong; Gu, Yilin; Li, Juan; Xu, Mingzhu; Wei, Qing; Wang, Yuanhong

    2015-01-01

    Powdery mildew is a fungal disease found in a wide range of plants and can significantly reduce crop yields. Bacterial strain LJ02 is a biocontrol agent (BCA) isolated from a greenhouse in Tianjin, China. In combination of morphological, physiological, biochemical and phylogenetic analyses, strain LJ02 was classified as a new member of Bacillus amyloliquefaciens. Greenhouse trials showed that LJ02 fermentation broth (LJ02FB) can effectively diminish the occurrence of cucurbits powdery mildew. When treated with LJ02FB, cucumber seedlings produced significantly elevated production of superoxide dismutase, peroxidase, polyphenol oxidase and phenylalanine ammonia lyase as compared to that of the control. We further confirmed that the production of free salicylic acid (SA) and expression of one pathogenesis-related (PR) gene PR-1 in cucumber leaves were markedly elevated after treating with LJ02FB, suggesting that SA-mediated defense response was stimulated. Moreover, LJ02FB-treated cucumber leaves could secrete resistance-related substances into rhizosphere that inhibit the germination of fungi spores and the growth of pathogens. Finally, we separated bacterium and its fermented substances to test their respective effects and found that both components have SA-inducing activity and bacterium plays major roles. Altogether, we identified a BCA against powdery mildew and its mode of action by inducing systemic resistance such as SA signaling pathway.

  15. Biocontrol of seed pathogens and growth promotion of common bean seedlings by Trichoderma harzianum

    Directory of Open Access Journals (Sweden)

    Daniel Diego Costa Carvalho

    2011-08-01

    Full Text Available The objective of this work was to evaluate isolates of Trichoderma harzianum regarding biocontrol of common bean seed-borne pathogens, plant growth promotion, and rhizosphere competence. Five isolates of T. harzianum were evaluated and compared with commercial isolate (Ecotrich, Carboxin+Thiram, and an absolute control. Bean seeds of the cultivar Jalo Precoce, contaminated with Aspergillus, Cladosporium, and Sclerotinia sclerotiorum, were microbiolized with antagonists, and seed health tests were carried out. Isolates were evaluated on autoclaved substrate and in field conditions. Ten days after sowing (DAS, plant length was measured. To test rhizosphere competence, isolates were applied in boxes containing autoclaved washed sand, and root colonization was evaluated at 10 DAS, using five plants per box. The most effective isolates in the seed health tests were: CEN287 and CEN289 to control Aspergillus; the commercial isolate to control Cladosporium; and CEN287 and CEN316 to control S. sclerotiorum. Isolates CEN289 and CEN290 promoted bean growth in greenhouse and field. Seed treatment with T. harzianum reduces the incidence of Aspergillus, Cladosporium, and S. sclerotiorum in 'Jalo Precoce' common bean seeds.

  16. Biosurfactants in plant-Pseudomonas interactions and their importance to biocontrol.

    Science.gov (United States)

    D'aes, Jolien; De Maeyer, Katrien; Pauwelyn, Ellen; Höfte, Monica

    2010-06-01

    Production of biosurfactants is a common feature in bacteria, and in particular in plant-associated species. These bacteria include many plant beneficial and plant pathogenic Pseudomonas spp., which produce primarily cyclic lipopeptide and rhamnolipid type biosurfactants. Pseudomonas-derived biosurfactants are involved in many important bacterial functions. By modifying surface properties, biosurfactants can influence common traits such as surface motility, biofilm formation and colonization. Biosurfactants can alter the bio-availability of exogenous compounds, such as nutrients, to promote their uptake, and of endogenous metabolites, including phenazine antibiotics, resulting in an enhanced biological activity. Antibiotic activity of biosurfactants towards microbes could play a role in intraspecific competition, self-defence and pathogenesis. In addition, bacterial surfactants can affect plants in different ways, either protecting them from disease, or acting as a toxin in a plant-pathogen interaction. Biosurfactants are involved in the biocontrol activity of an increasing number of Pseudomonas strains. Consequently, further insight into the roles and activities of surfactants produced by bacteria could provide means to optimize the use of biological control as an alternative crop protection strategy.

  17. Plot- and landscape-level changes in climate and vegetation following defoliation of exotic saltcedar (Tamarix sp.) from the biocontrol agent Diorhabda carinulata along a stream in the Mojave Desert (USA)

    Science.gov (United States)

    Bateman, H.L.; Nagler, P.L.; Glenn, E.P.

    2013-01-01

    The biocontrol agent, northern tamarisk beetle (Diorhabda carinulata), has been used to defoliate non-native saltcedar (Tamarix spp.) in USA western riparian systems since 2001. Biocontrol has the potential to impact biotic communities and climatic conditions in affected riparian areas. To determine the relationships between biocontrol establishment and effects on vegetation and climate at the plot and landscape scales, we measured temperature, relative humidity, foliage canopy, solar radiation, and used satellite imagery to assess saltcedar defoliation and evapotranspiration (ET) along the Virgin River in the Mojave Desert. Following defoliation solar radiation increased, daily humidity decreased, and maximum daily temperatures tended to increase. MODIS and Landsat satellite imagery showed defoliation was widespread, resulting in reductions in ET and vegetation indices. Because biocontrol beetles are spreading into new saltcedar habitats on arid western rivers, and the eventual equilibrium between beetles and saltcedar is unknown, it is necessary to monitor trends for ecosystem functions and higher trophic-level responses in habitats impacted by biocontrol.

  18. Selection and characterization of Argentine isolates of Trichoderma harzianum for effective biocontrol of Septoria leaf blotch of wheat.

    Science.gov (United States)

    Stocco, Marina C; Mónaco, Cecilia I; Abramoff, Cecilia; Lampugnani, Gladys; Salerno, Graciela; Kripelz, Natalia; Cordo, Cristina A; Consolo, Verónica F

    2016-03-01

    Species of the genus Trichoderma are economically important as biocontrol agents, serving as a potential alternative to chemical control. The applicability of Trichoderma isolates to different ecozones will depend on the behavior of the strains selected from each zone. The present study was undertaken to isolate biocontrol populations of Trichoderma spp. from the Argentine wheat regions and to select and characterize the best strains of Trichoderma harzianum by means of molecular techniques. A total of 84 out of the 240 strains of Trichoderma were able to reduce the disease severity of the leaf blotch of wheat. Thirty-seven strains were selected for the reduction equal to or greater than 50% of the severity, compared with the control. The percentage values of reduction of the pycnidial coverage ranged between 45 and 80%. The same last strains were confirmed as T. harzianum by polymerase chain reaction amplification of internal transcribed spacers, followed by sequencing. Inter-simple sequence repeat was used to examine the genetic variability among isolates. This resulted in a total of 132 bands. Further numerical analysis revealed 19 haplotypes, grouped in three clusters (I, II, III). Shared strains, with different geographical origins and isolated in different years, were observed within each cluster. The origin of the isolates and the genetic group were partially related. All isolates from Paraná were in cluster I, all isolates from Lobería were in cluster II, and all isolates from Pergamino and Santa Fe were in cluster III. Our results suggest that the 37 native strains of T. harzianum are important in biocontrol programs and could be advantageous for the preparation of biopesticides adapted to the agroecological conditions of wheat culture.

  19. Phytohormone profiles induced by trichoderma isolates correspond with their biocontrol and plant growth-promoting activity on melon plants.

    Science.gov (United States)

    Martínez-Medina, Ainhoa; Del Mar Alguacil, Maria; Pascual, Jose A; Van Wees, Saskia C M

    2014-07-01

    The application of Trichoderma strains with biocontrol and plant growth-promoting capacities to plant substrates can help reduce the input of chemical pesticides and fertilizers in agriculture. Some Trichoderma isolates can directly affect plant pathogens, but they also are known to influence the phytohormonal network of their host plant, thus leading to an improvement of plant growth and stress tolerance. In this study, we tested whether alterations in the phytohormone signature induced by different Trichoderma isolates correspond with their ability for biocontrol and growth promotion. Four Trichoderma isolates were collected from agricultural soils and were identified as the species Trichoderma harzianum (two isolates), Trichoderma ghanense, and Trichoderma hamatum. Their antagonistic activity against the plant pathogen Fusarium oxysporum f. sp. melonis was tested in vitro, and their plant growth-promoting and biocontrol activity against Fusarium wilt on melon plants was examined in vivo, and compared to that of the commercial strain T. harzianum T-22. Several growth- and defense-related phytohormones were analyzed in the shoots of plants that were root-colonized by the different Trichoderma isolates. An increase in auxin and a decrease in cytokinins and abscisic acid content were induced by the isolates that promoted the plant growth. Principal component analysis (PCA) was used to evaluate the relationship between the plant phenotypic and hormonal variables. PCA pointed to a strong association of auxin induction with plant growth stimulation by Trichoderma. Furthermore, the disease-protectant ability of the Trichoderma strains against F. oxysporum infection seems to be more related to their induced alterations in the content of the hormones abscisic acid, ethylene, and the cytokinin trans-zeatin riboside than to the in vitro antagonism activity against F. oxysporum.

  20. Characterization of antagonistic-potential of two Bacillus strains and their biocontrol activity against Rhizoctonia solani in tomato.

    Science.gov (United States)

    Solanki, Manoj Kumar; Singh, Rajesh Kumar; Srivastava, Supriya; Kumar, Sudheer; Kashyap, Prem Lal; Srivastava, Alok K

    2015-01-01

    To investigate the biocontrol mechanism of two antagonistic Bacillus strains (Bacillus subtilis MB14 and Bacillus amyloliquefaciens MB101), three in vitro antagonism assays were screened and the results were concluded that both strains inhibited Rhizoctonia solani growth in a similar manner by dual culture assay, but the maximum percent of inhibition only resulted with MB101 by volatile and diffusible metabolite assays. Moreover, cell free supernatant (CFS) of MB101 also showed significant (p > 0.05) growth inhibition as compared to MB14, when 10 and 20% CFS mix with the growth medium of R. solani. After in vitro-validation, both strains were evaluated under greenhouse and the results concluded that strain MB101 had significant biocontrol potential as compared to MB14. Strain MB101 was enhanced the plant height, biomass and chlorophyll content of tomato plant through a higher degree of root colonization. In field trials, strain MB101 showed higher lessening in root rot symptoms with significant fruit yield as compare to strain MB14 and infected control. Next to the field study, the presence of four antibiotic genes (srfAA, fenD, ituC, and bmyB) also concluded the antifungal nature of both Bacillus strains. Phylogenetic analysis of protein sequences revealed a close relatedness of three genes (srfAA, fenD, and ituC) with earlier reported sequences of B. subtilis and B. amyloliquefaciens. However, bmyB showed heterogeneity in among both strains (MB14 and MB101) and it may be concluded that higher degree of antagonism, root colonization and different antibiotic producing genes may play an important role in biocontrol mechanism of strain MB101.

  1. Phosphorus uptake of an arbuscular mycorrhizal fungus is not effected by the biocontrol bacterium ¤Burkholderia cepacia¤

    DEFF Research Database (Denmark)

    Ravnskov, S.; Larsen, J.; Jakobsen, I.

    2002-01-01

    the amount of branched PLFAs suggesting a reduction in the population of Gram-positive bacteria in these cases. In conclusion, the B. cepacia seems to have no impact on neither mycorrhiza formation nor on the functioning of the AM fungus G. intraradices in terms of P transport, whereas our results suggest......The biocontrol bacterium Burkholderia cepacia is known to suppress a broad range of root pathogenic fungi, while its impact on other beneficial non-target organisms such as arbuscular mycorrhizal (AM) fungi is unknown. Direct interactions between five B. cepacia strains and the AM fungus, Glomus...

  2. Evaluación de hongos y bacterias aislados de gallinaza en el biocontrol de Sclerotium cepivorum Berk

    OpenAIRE

    Gladys Amparo Sarmiento; Jorge Velandía-Monsalve

    2013-01-01

    Objetivo. Seleccionar hongos y bacterias de la gallinaza por su capacidad antagónica en el biocontrol de S. cepivorum in vitro y en invernadero. Materiales y métodos. De dos fuentes de gallinaza, una pura y otra compuesta, se tomaron sendas muestras de 100 g, se colocaron en erlemeyers, se agregó agua destilada estéril hasta completar un litro y se agitó durante 5 minutos. A partir de esta suspensión se prepararon diluciones de 1x10-1 hasta 1x10-4, y se evaluó el crecimiento y esporulación de...

  3. Biocontrol traits of plant growth suppressive arbuscular mycorrhizal fungi against root rot in tomato caused by Pythium aphanidermatum

    DEFF Research Database (Denmark)

    Larsen, John; Graham, James H.; Cubero, Jaime

    2012-01-01

    Arbuscular mycorrhizal (AM) fungi known to cause plant growth depressions in tomato were examined for their biocontrol effects against root rot caused by Pythium aphanidermatum. The main hypothesis was that plant growth suppressive AM fungi would elicit a defence response in the host plant reducing...... after AM fungi inoculation, roots were challenged with P. aphanidermatum. Variables evaluated at each harvest were root colonization levels of the interacting fungi, plant growth responses, and expression of a plant pathogenesis related protein gene (PR-1). All of the tested AM fungi caused marked...

  4. Evaluation of the enzymatic activity of Trichoderma inhamatum (BOL-12QD as possible biocontroller

    Directory of Open Access Journals (Sweden)

    García-Espejo Cielo Noemí

    2016-02-01

    Full Text Available It is known that Trichoderma spp. acts as a natural biocontroller of pathogen fungi, is for this reason, that this research studies the potential of its hydrolytic enzyme activity. In this article, first we determined that the speed of growth of Trichoderma inhamatum cepa BOL-12QD is 9 hours. Later, we proposed a simple and sensitive method based in the use of basal media (BM with coloidal chitin as the only carbon resource and supplemented with bromocresol purple for the qualitative determination of chitinase activi-ty. On the other hand, it was determined the celullolytic and proteolytic activities of Trichoderma in-hamatum cepa BOL-12QD and it was observed that agitation, type and concentration of sustrate are determinant factors in enzymatic production. Then, we evaluated the cellulolytic activity of Trichoderma inhamatum cepa BOL-12QD in agitation and stationary using carboxymethylcellulose (CMC as sustrate, finding that using a 2% of sustrate the highest activity is registered at 8 days of incubation in agitation with a value of 99.23 IU/L. In relation to the results at stationary the optimal value is at the fourth day with a value of 92.76 IU/L. The protease activity it was determined taking in consideration variables of agitation and stationary, using different types and concentration of sustrate at 2%, 4% y 6% (w/v of meat extract, 1%, 3%, 5% (w/v of jelly and 1%, 2%, 4% (w/v of casein. The highest protease activity was obtained at the end of the sev-enth day with an enzymatic activity of 3075.45 IU/L at stationary using a concentration of 6% (w/v of meat extract, and using jelly at 3% (w/v at stationary it was found an activity of 568.36 IU/L on the tenth day and in agitation a value of 547.27 IU/L was reached on the twelveth day, while using casein at 1% (w/v at stationary an activity of 407.06 IU/L is reached in the fifth day, and in agitation at 4% (w/v of casein a value of 547.27 IU/L is obtained on the twelfth day, while using

  5. Assessment of virally vectored autoimmunity as a biocontrol strategy for cane toads.

    Directory of Open Access Journals (Sweden)

    Jackie A Pallister

    Full Text Available BACKGROUND: The cane toad, Bufo (Chaunus marinus, is one of the most notorious vertebrate pests introduced into Australia over the last 200 years and, so far, efforts to identify a naturally occurring B. marinus-specific pathogen for use as a biological control agent have been unsuccessful. We explored an alternative approach that entailed genetically modifying a pathogen with broad host specificity so that it no longer caused disease, but carried a gene to disrupt the cane toad life cycle in a species specific manner. METHODOLOGY/PRINCIPAL FINDINGS: The adult beta globin gene was selected as the model gene for proof of concept of autoimmunity as a biocontrol method for cane toads. A previous report showed injection of bullfrog tadpoles with adult beta globin resulted in an alteration in the form of beta globin expressed in metamorphs as well as reduced survival. In B. marinus we established for the first time that the switch from tadpole to adult globin exists. The effect of injecting B. marinus tadpoles with purified recombinant adult globin protein was then assessed using behavioural (swim speed in tadpoles and jump length in metamorphs, developmental (time to metamorphosis, weight and length at various developmental stages, protein profile of adult globin and genetic (adult globin mRNA levels measures. However, we were unable to detect any differences between treated and control animals. Further, globin delivery using Bohle iridovirus, an Australian ranavirus isolate belonging to the Iridovirus family, did not reduce the survival of metamorphs or alter the form of beta globin expressed in metamorphs. CONCLUSIONS/SIGNIFICANCE: While we were able to show for the first time that the switch from tadpole to adult globin does occur in B. marinus, we were not able to induce autoimmunity and disrupt metamorphosis. The short development time of B. marinus tadpoles may preclude this approach.

  6. Chitinases from the Plant Disease Biocontrol Agent, Stenotrophomonas maltophilia C3.

    Science.gov (United States)

    Zhang, Z; Yuen, G Y; Sarath, G; Penheiter, A R

    2001-02-01

    ABSTRACT Stenotrophomonas maltophilia strain C3, a biocontrol agent of Bipolaris sorokiniana in turfgrass, produced chitinases in broth media containing chitin. Chitinases were partially purified from culture fluid by ammonium sulfate precipitation and chitin affinity chromatography. The chromatography fraction with the highest specific chitinase activity was inhibitory to conidial germination and germ-tube elongation of B. sorokiniana, but it was less inhibitory than the protein fraction or the raw culture filtrate. The fraction exhibited strong exochitinase and weak endo-chitinase activity. Optimum temperature and pH for chitinase activity were 45 to 50 degrees C and 4.5 to 5.0, respectively. Chitinase activity was inhibited by Hg(2+) and Fe(3+), but not by other metal ions or enzyme inhibitors. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the chromatography fraction revealed the presence of five protein bands of 25, 32, 48, 65, and 75 kDa. Partial amino acid sequences of the 32-, 65-, and 75-kDa proteins indicated that they are homologous to known bacterial chitinases. There was no homology found in the partial amino acid sequences of the 25- and 48-kDa proteins to any known chitinases. Five chitinase-active proteins were detected in the protein and chromatography fractions by activity gels, but when each protein was extracted and re-electrophoresed separately under denaturing conditions, only 32- or 48-kDa proteins were revealed. It was concluded that strain C3 produces at least two chitinases that are antifungal.

  7. Three New Pierce's Disease Pathogenicity Effectors Identified Using Xylella fastidiosa Biocontrol Strain EB92-1.

    Directory of Open Access Journals (Sweden)

    Shujian Zhang

    Full Text Available Xylella fastidiosa (X. fastidiosa infects a wide range of plant hosts and causes economically serious diseases, including Pierce's Disease (PD of grapevines. X. fastidiosa biocontrol strain EB92-1 was isolated from elderberry and is infectious and persistent in grapevines but causes only very slight symptoms under ideal conditions. The draft genome of EB92-1 revealed that it appeared to be missing genes encoding 10 potential PD pathogenicity effectors found in Temecula1. Subsequent PCR and sequencing analyses confirmed that EB92-1 was missing the following predicted effectors found in Temecula1: two type II secreted enzymes, including a lipase (LipA; PD1703 and a serine protease (PD0956; two identical genes encoding proteins similar to Zonula occludens toxins (Zot; PD0915 and PD0928, and at least one relatively short, hemagglutinin-like protein (PD0986. Leaves of tobacco and citrus inoculated with cell-free, crude protein extracts of E. coli BL21(DE3 overexpressing PD1703 exhibited a hypersensitive response (HR in less than 24 hours. When cloned into shuttle vector pBBR1MCS-5, PD1703 conferred strong secreted lipase activity to Xanthomonas citri, E. coli and X. fastidiosa EB92-1 in plate assays. EB92-1/PD1703 transformants also showed significantly increased disease symptoms on grapevines, characteristic of PD. Genes predicted to encode PD0928 (Zot and a PD0986 (hemagglutinin were also cloned into pBBR1MCS-5 and moved into EB92-1; both transformants also showed significantly increased symptoms on V. vinifera vines, characteristic of PD. Together, these results reveal that PD effectors include at least a lipase, two Zot-like toxins and a possibly redundant hemagglutinin, none of which are necessary for parasitic survival of X. fastidiosa populations in grapevines or elderberry.

  8. Biocontrol and Rapid Detection of Food-borne Pathogens Using Bacteriophages and Endolysins

    Directory of Open Access Journals (Sweden)

    Jaewoo eBai

    2016-04-01

    Full Text Available Bacteriophages have been suggested as natural food preservatives as well as rapid detection materials for food-borne pathogens in various foods. Since Listeria monocytogenes-targeting phage cocktail (ListShield was approved for applications in foods, numerous phages have been screened and experimentally characterized for phage applications in foods. A single phage and phage cocktail treatments to various foods contaminated with food-borne pathogens including E. coli O157:H7, Salmonella enterica, Campylobacter jejuni, Listeria monocytogenes, Staphylococcus aureus, Cronobacter sakazakii, and Vibrio spp. revealed that they have great potential to control various food-borne pathogens and may be alternative for conventional food preservatives. In addition, phage-derived endolysins with high host specificity and host lysis activities may be preferred to food applications rather than phages. For rapid detection of food-borne pathogens, cell-wall binding domains (CBDs from endolysins have been suggested due to their high host-specific binding. Fluorescence-tagged CBDs have been successfully evaluated and suggested to be alternative materials of expensive antibodies for various detection applications. Most recently, reporter phage systems have been developed and tested to confirm their usability and accuracy for specific detection. These systems revealed some advantages like rapid detection of only viable pathogenic cells without interference by food components in a very short reaction time, suggesting that these systems may be suitable for monitoring of pathogens in foods. Consequently, phage is the next-generation biocontrol agent as well as rapid detection tool to confirm and even identify the food-borne pathogens present in various foods.

  9. Biocontrol of Botrytis cinerea by successful introduction of Pantoea ananatis in the grapevine phyllosphere

    Directory of Open Access Journals (Sweden)

    Gasser F

    2012-12-01

    Full Text Available Florian Gasser,1 Massimiliano Cardinale,1 Barbara Schildberger,2 Gabriele Berg11Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria; 2Höhere Bundesanstalt und Bundesamt für Wein-und Obstbau, Klosterneuburg, AustriaBackground and aims: The fungus Botrytis cinerea is a common problem in viticulture and leads to serious losses in both yield and quality. The objective was to study the potential of the antagonist Pantoea ananatis BLBT1-08 for controlling this disease.Methods: Pathogen suppression by Pantoea treatments was investigated in different field trials and in detached leaf assays. The mode of action was studied by confocal laser scanning microscopy of treated grape leaves and by in vitro assays.Results: The introduction of P. ananatis BLBT1-08 in a 3-year field trial resulted in statistically significant reduction of disease symptoms. However, B. cinerea abundance, measured by quantitative real-time polymerase chain reaction of a B. cinerea specific gene, was not reduced when compared to non-treated, symptom-free leaves. A DsRed fluorescent protein labeled BLBT1-08 strain showed a high phyllosphere competence and competition on the leaf surface, but did not colonize the inner parts of plant tissue. Germination of B. cinerea was not inhibited by BLBT1-08 on the leaf, but mycelial growth and symptoms were suppressed without direct pathogen-antagonist contact. The antimicrobial activity was amino acid and temperature dependent.Conclusion: P. ananatis BLBT1-08 is a competitive and promising biocontrol agent for the control of B. cinerea and is highly effective at reducing disease incidence.Keywords: biological control, sustainable viticulture, antagonism

  10. Biocontrol and Rapid Detection of Food-Borne Pathogens Using Bacteriophages and Endolysins.

    Science.gov (United States)

    Bai, Jaewoo; Kim, You-Tae; Ryu, Sangryeol; Lee, Ju-Hoon

    2016-01-01

    Bacteriophages have been suggested as natural food preservatives as well as rapid detection materials for food-borne pathogens in various foods. Since Listeria monocytogenes-targeting phage cocktail (ListShield) was approved for applications in foods, numerous phages have been screened and experimentally characterized for phage applications in foods. A single phage and phage cocktail treatments to various foods contaminated with food-borne pathogens including E. coli O157:H7, Salmonella enterica, Campylobacter jejuni, Listeria monocytogenes, Staphylococcus aureus, Cronobacter sakazakii, and Vibrio spp. revealed that they have great potential to control various food-borne pathogens and may be alternative for conventional food preservatives. In addition, phage-derived endolysins with high host specificity and host lysis activities may be preferred to food applications rather than phages. For rapid detection of food-borne pathogens, cell-wall binding domains (CBDs) from endolysins have been suggested due to their high host-specific binding. Fluorescence-tagged CBDs have been successfully evaluated and suggested to be alternative materials of expensive antibodies for various detection applications. Most recently, reporter phage systems have been developed and tested to confirm their usability and accuracy for specific detection. These systems revealed some advantages like rapid detection of only viable pathogenic cells without interference by food components in a very short reaction time, suggesting that these systems may be suitable for monitoring of pathogens in foods. Consequently, phage is the next-generation biocontrol agent as well as rapid detection tool to confirm and even identify the food-borne pathogens present in various foods.

  11. Amblyseius swirskii: what made this predatory mite such a successful biocontrol agent?

    Science.gov (United States)

    Calvo, F Javier; Knapp, Markus; van Houten, Yvonne M; Hoogerbrugge, Hans; Belda, José E

    2015-04-01

    The predatory mite Amblyseius swirskii quickly became one of the most successful biocontrol agents in protected cultivation after its introduction into the market in 2005 and is now released in more than 50 countries. There are several key factors contributing to this success: (1) it can control several major pests including the western flower thrips, Frankliniella occidentalis, the whiteflies Bemisia tabaci and Trialeurodes vaporariorum and the broad mite, Polyphagotarsonemus latus, simultaneously in vegetables and ornamental crops; (2) it can develop and reproduce feeding on non-prey food sources such as pollen, which allows populations of the predator to build up on plants before the pests are present and to persist in the crop during periods when prey is scarce or absent; and (3) it can be easily reared on factitious prey, which allows economic mass production. However, despite the fact that A. swirskii provides growers with a robust control method, external demands were initially a key factor in promoting the use of this predator, particularly in Spain. In 2006, when exports of fresh vegetables from Spain were stopped due to the presence of pesticide residues, growers were forced to look for alternatives to chemical control. This resulted in the massive adoption of biological control-based integrated pest management programmes based on the use of A. swirskii in sweet pepper. Biological control increased from 5 % in 2005, 1 year before A. swirskii was commercially released, to almost 100 % of a total 6,000 ha of protected sweet pepper in Spain within 3 years. Later, it was demonstrated that A. swirskii was equally effective in other crops and countries, resulting in extensive worldwide use of A. swirskii in greenhouses.

  12. What magnitude are observed non-target impacts from weed biocontrol?

    Science.gov (United States)

    Suckling, David Maxwell; Sforza, René François Henri

    2014-01-01

    A systematic review focused by plant on non-target impacts from agents deliberately introduced for the biological control of weeds found significant non-target impacts to be rare. The magnitude of direct impact of 43 biocontrol agents on 140 non-target plants was retrospectively categorized using a risk management framework for ecological impacts of invasive species (minimal, minor, moderate, major, massive). The vast majority of agents introduced for classical biological control of weeds (>99% of 512 agents released) have had no known significant adverse effects on non-target plants thus far; major effects suppressing non-target plant populations could be expected to be detectable. Most direct non-target impacts on plants (91.6%) were categorized as minimal or minor in magnitude with no known adverse long-term impact on non-target plant populations, but a few cacti and thistles are affected at moderate (n = 3), major (n = 7) to massive (n = 1) scale. The largest direct impacts are from two agents (Cactoblastis cactorum on native cacti and Rhinocyllus conicus on native thistles), but these introductions would not be permitted today as more balanced attitudes exist to plant biodiversity, driven by both society and the scientific community. Our analysis shows (as far as is known), weed biological control agents have a biosafety track record of >99% of cases avoiding significant non-target impacts on plant populations. Some impacts could have been overlooked, but this seems unlikely to change the basic distribution of very limited adverse effects. Fewer non-target impacts can be expected in future because of improved science and incorporation of wider values. Failure to use biological control represents a significant opportunity cost from the certainty of ongoing adverse impacts from invasive weeds. It is recommended that a simple five-step scale be used to better communicate the risk of consequences from both action (classical biological control) and no

  13. Biocontrol Characteristics of Bacillus Species in Suppressing Stem Rot of Grafted Cactus Caused by Bipolaris cactivora.

    Science.gov (United States)

    Bae, Sooil; Kim, Sang Gyu; Kim, Young Ho

    2013-03-01

    One of the most important limiting factors for the production of the grafted cactus in Korea is the qualitative and quantitative yield loss derived from stem rots especially caused by Bipolaris cactivora. This study is aimed to develop microbial control agents useful for the control of the bipolaris stem rot. Two bacteria (GA1-23 and GA4-4) selected out of 943 microbial isolates because of their strong antibiotic activity against B. cactivora were identified as Bacillus subtilis and B. amyloliquefaciens, respectively, by the cultural characteristics, Biolog program and 16S rRNA sequencing analyses. Both bacterial isolates significantly inhibited the conidial germination and mycelial growth of the pathogen with no significant difference between the two, of which the inhibitory efficacies varied depending on the cultural conditions such as temperature, nutritional compositions and concentrations. Light and electron microscopy of the pathogen treated with the bacterial isolates showed the inhibition of spore germination with initial malformation of germ tubes and later formation of circle-like vesicles with no hyphal growth and hyphal disruption sometimes accompanied by hyphal swellings and shrinkages adjacent to the bacteria, suggesting their antibiotic mode of antagonistic activity. Control efficacy of B. subtilis GA1-23 and B. amyloliquefaciens GA4-4 on the cactus stem rot were not as high as but comparable to that of fungicide difenoconazole when they were treated simultaneously at the time of pathogen inoculation. All of these results suggest the two bacterial isolates have a good potential to be developed as biocontrol agents for the bipolaris stem rot of the grafted cactus.

  14. Biocontrol Characteristics of Bacillus Species in Suppressing Stem Rot of Grafted Cactus Caused by Bipolaris cactivora

    Directory of Open Access Journals (Sweden)

    Sooil Bae

    2013-03-01

    Full Text Available One of the most important limiting factors for the production of the grafted cactus in Korea is the qualitative and quantitative yield loss derived from stem rots especially caused by Bipolaris cactivora. This study is aimed to develop microbial control agents useful for the control of the bipolaris stem rot. Two bacteria (GA1-23 and GA4-4 selected out of 943 microbial isolates because of their strong antibiotic activity against B. cactivora were identified as Bacillus subtilis and B. amyloliquefaciens, respectively, by the cultural characteristics, Biolog program and 16S rRNA sequencing analyses. Both bacterial isolates significantly inhibited the conidial germination and mycelial growth of the pathogen with no significant difference between the two, of which the inhibitory efficacies varied depending on the cultural conditions such as temperature, nutritional compositions and concentrations. Light and electron microscopy of the pathogen treated with the bacterial isolates showed the inhibition of spore germination with initial malformation of germ tubes and later formation of circle-like vesicles with no hyphal growth and hyphal disruption sometimes accompanied by hyphal swellings and shrinkages adjacent to the bacteria, suggesting their antibiotic mode of antagonistic activity. Control efficacy of B. subtilis GA1-23 and B. amyloliquefaciens GA4-4 on the cactus stem rot were not as high as but comparable to that of fungicide difenoconazole when they were treated simultaneously at the time of pathogen inoculation. All of these results suggest the two bacterial isolates have a good potential to be developed as biocontrol agents for the bipolaris stem rot of the grafted cactus.

  15. Biocontrol Characteristics of Bacillus Species in Suppressing Stem Rot of Grafted Cactus Caused by Bipolaris cactivora

    Science.gov (United States)

    Bae, Sooil; Kim, Sang Gyu; Kim, Young Ho

    2013-01-01

    One of the most important limiting factors for the production of the grafted cactus in Korea is the qualitative and quantitative yield loss derived from stem rots especially caused by Bipolaris cactivora. This study is aimed to develop microbial control agents useful for the control of the bipolaris stem rot. Two bacteria (GA1-23 and GA4-4) selected out of 943 microbial isolates because of their strong antibiotic activity against B. cactivora were identified as Bacillus subtilis and B. amyloliquefaciens, respectively, by the cultural characteristics, Biolog program and 16S rRNA sequencing analyses. Both bacterial isolates significantly inhibited the conidial germination and mycelial growth of the pathogen with no significant difference between the two, of which the inhibitory efficacies varied depending on the cultural conditions such as temperature, nutritional compositions and concentrations. Light and electron microscopy of the pathogen treated with the bacterial isolates showed the inhibition of spore germination with initial malformation of germ tubes and later formation of circle-like vesicles with no hyphal growth and hyphal disruption sometimes accompanied by hyphal swellings and shrinkages adjacent to the bacteria, suggesting their antibiotic mode of antagonistic activity. Control efficacy of B. subtilis GA1-23 and B. amyloliquefaciens GA4-4 on the cactus stem rot were not as high as but comparable to that of fungicide difenoconazole when they were treated simultaneously at the time of pathogen inoculation. All of these results suggest the two bacterial isolates have a good potential to be developed as biocontrol agents for the bipolaris stem rot of the grafted cactus. PMID:25288927

  16. Evaluation of yeasts from Tibetan fermented products as agents for biocontrol of blue mold of Nashi pear fruits.

    Science.gov (United States)

    Hu, Hao; Xu, Yang; Lu, Huang-ping; Xiao, Rui; Zheng, Xiao-dong; Yu, Ting

    2015-04-01

    A total of 20 strains of yeast isolated from Tibetan fermented products were screened for antagonism against blue mold of pear caused by Penicillium expansum. Six isolates that inhibited incidence of postharvest decay by 35% or more were selected for further screening. Among them, the most effective was Rhodotorula mucilaginosa. The results showed that washed cell suspensions of R. mucilaginosa yielded better antagonistic efficacy than unwashed cell-culture mixtures, cell-free culture filtrates, and autoclaved cell cultures. Biocontrol activity improved with increasing concentrations of incubated cells. The best concentration was 1×10(8) cells/ml, at which the incidence of decay was only 16.7% after 6 d of incubation. The germination of conidia of P. expansum in vitro was significantly inhibited by both washed cell-suspensions and unwashed cell-culture mixtures. Rapid colonization by yeast at different concentrations showed a relationship between yeast-cell concentration and biocontrol activity. Although the titratable acidity of pear fruits increased after treatment, R. mucilaginosa did not affect the total soluble solids or ascorbic acid content. This is the first study to report that the yeast R. mucilaginosa from Tibet Autonomous Region of China may have potential as an antagonist to control the postharvest decay of pear fruits.

  17. A mutant of the nematophagous fungus Paecilomyces lilacinus (Thom) is a novel biocontrol agent for Sclerotinia sclerotiorum.

    Science.gov (United States)

    Yang, Fan; Abdelnabby, Hazem; Xiao, Yannong

    2015-12-01

    Sclerotinia sclerotiorum causes severe stem rot and yield loss in oilseed rape (Brassica napus L.) and other crops worldwide. Extensive studies have been conducted on Paecilomyces lilacinus as a nematophagous bioagent. However, no reports stated the effect of P. lilacinus as a biocontrol agent against oilseed rape rot S. sclerotiorum. This study describes such effect in lab and field trials using the new transformant pt361 derived from the wild strain P. lilacinus 36-1. Unlike the wild-type strain, the mutant pt361 showed high antagonistic effect against S. Sclerotiorum A. Under lab conditions, the pt361 inhibited (65%) radial mycelial growth of S. sclerotiorum in dual culture test producing 5.9 mm inhibition zone IZ in front of the S. sclerotiorum colony. Moreover, the cell-free filtrate of pt361 culture showed strong inhibitory effects (60.3-100%) on mycelial growth of S. sclerotiorum. In leaf detached assay, pt361 significantly (p biocontrol agent against oilseed rape Sclerotinia stem rot.

  18. Endospore production allows using spray-drying as a possible formulation system of the biocontrol agent Bacillus subtilis CPA-8.

    Science.gov (United States)

    Yánez-Mendizabal, V; Viñas, I; Usall, J; Cañamás, T; Teixidó, N

    2012-04-01

    The role of endospore production by Bacillus subtilis CPA-8 on survival during spray-drying was investigated by comparison with a non-spore-forming biocontrol agent Pantoea agglomerans CPA-2. Endospore formation promoted heat resistance in CPA-8 depending on growth time (72 h cultures were more resistant than 24 h ones). The survival of CPA-8 and CPA-2 after spray-drying was determined after being grown in optimised media for 24 and 72 h. Spray-dried 72 h CPA-8 had the best survival (32%), while CPA-2 viability was less than 2%. CPA-8 survival directly related with its ability to produce endospores. Spray-dried CPA-8 reduced Monilinia fructicola conidia germination similarly to fresh cells, demonstrating that spray-drying did not adversely affect biocontrol efficacy. Endospore production thus improves CPA-8 resistance to spray-drying. These results can provide a reliable basis for optimising of the spray-drying formulation process for CPA-8 and other microorganisms.

  19. Bacillus methylotrophicus Strain NKG-1, Isolated from Changbai Mountain, China, Has Potential Applications as a Biofertilizer or Biocontrol Agent

    Science.gov (United States)

    Ge, Beibei; Liu, Binghua; Nwet, Thinn Thinn; Zhao, Wenjun; Shi, Liming; Zhang, Kecheng

    2016-01-01

    Chemical pesticides are widely used in agriculture, which endangers both environmental health and food safety. Biocontrol is an environmentally-friendly and cost-effective green technique in environmental protection and agricultural production; it generally uses selected bioresources, including beneficial microorganisms. We isolated a novel bacterial strain (NKG-1) from the rare dormant volcanic soils of Changbai Mountain in China’s Jilin Province. The strain was identified as Bacillus methylotrophicus using morphological, biochemical, physiological, and phylogenetic 16S rDNA sequencing data. This strain was able to suppress mycelial growth and conidial germination of numerous plant pathogenic fungi on solid media. A greenhouse experiment showed that application of NKG-1 fermentation broth prior to inoculation of Botrytis cinerea, the cause of gray tomato mold, inhibited growth of the mold by 60%. Furthermore, application of a 100× dilution of NKG-1 fermentation broth to tomato seedlings yielded a significant increase in seedling fresh weight (27.4%), seedling length (12.5%), and root length (57.7%) compared to the control. When the same dosage was applied in the field, we observed increases in tomato plant height (14.7%), stem diameter (12.7%), crown width (16.3%), and maximum fruit diameter (11.5%). These results suggest that NKG-1 has potential commercial application as a biofertilizer or biocontrol agent. PMID:27832162

  20. Genetic responses induced in olive roots upon colonization by the biocontrol endophytic bacterium Pseudomonas fluorescens PICF7.

    Directory of Open Access Journals (Sweden)

    Elisabetta Schilirò

    Full Text Available Knowledge on the genetic basis underlying interactions between beneficial bacteria and woody plants is still very limited, and totally absent in the case of olive. We aimed to elucidate genetic responses taking place during the colonization of olive roots by the native endophyte Pseudomonas fluorescens PICF7, an effective biocontrol agent against Verticillium wilt of olive. Roots of olive plants grown under non-gnotobiotic conditions were collected at different time points after PICF7 inoculation. A Suppression Subtractive Hybridization cDNA library enriched in induced genes was generated. Quantitative real time PCR (qRT-PCR analysis validated the induction of selected olive genes. Computational analysis of 445 olive ESTs showed that plant defence and response to different stresses represented nearly 45% of genes induced in PICF7-colonized olive roots. Moreover, quantitative real-time PCR (qRT-PCR analysis confirmed induction of lipoxygenase, phenylpropanoid, terpenoids and plant hormones biosynthesis transcripts. Different classes of transcription factors (i.e., bHLH, WRKYs, GRAS1 were also induced. This work highlights for the first time the ability of an endophytic Pseudomonas spp. strain to mount a wide array of defence responses in an economically-relevant woody crop such as olive, helping to explain its biocontrol activity.

  1. Evidence for biotrophic lifestyle and biocontrol potential of dark septate endophyte Harpophora oryzae to rice blast disease.

    Science.gov (United States)

    Su, Zhen-Zhu; Mao, Li-Juan; Li, Na; Feng, Xiao-Xiao; Yuan, Zhi-Lin; Wang, Li-Wei; Lin, Fu-Cheng; Zhang, Chu-Long

    2013-01-01

    The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA) signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS) and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast.

  2. Teste de especificidade hospedeira de Phaedon confinis (Coleoptera, Chrysomelidae, um potencial agente de biocontrole de Senecio brasiliensis (Asteraceae.

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    Julianne Milléo

    2011-07-01

    Abstract. Senecio brasiliensis (Spreng. Less when ingested by cattle and horses, the plant causes seneciosis, a serious poisoning. Due to the great financial losses to cattle ranchers, controlling the plant using insects has become attractive. Systematic survey efforts have revealed that Phaedon confinis Klug causes serious damage to the plant, and may be a great biocontrol agent. The object was to extend the tests of host specificity to 52 plants using 1st larval instar and adult chrysomelid bettles. The insects were submitted to “no-choice” and “multiple-choice” tests. The following results were obtained: “NO-CHOICE” L1 – 52 plants tested: null 90.39%; negligible damage 5.77%; light 1.92%; and normal in only S. brasiliensis 1.92%, where 31.67% of larvae obtained an adult phase. “NO-CHOICE” ADULTS – 46 plants. Null damage was recorded in 82.60%; 13.04% showed negligible damage; 2.17% light; 2.17% normal in S. brasiliensis. The chysomelids oviposited during observation days only on S. brasiliensis leaves. 615 eggs were oviposited with 73.01% viability. “MULTIPLE CHOICE” LARVAE – nine plants tested. 66.67% null; 11.11% weak; 11.11% negligible damage; and 11.11% normal in S. brasiliensis. The results indicate that the normal diet, oviposition, survival and development of P. confinis is restricted to S. brasiliensis and corroborates its potential as a biocontrol agent.

  3. Intracellular trehalose and sorbitol synergistically promoting cell viability of a biocontrol yeast, Pichia anomala, for aflatoxin reduction.

    Science.gov (United States)

    Hua, Sui Sheng T; Hernlem, Bradley J; Yokoyama, Wallace; Sarreal, Siov Bouy L

    2015-05-01

    Pichia anomala (Wickerhamomyces anomalus) WRL-076 was discovered by a visual screening bioassay for its antagonism against Aspergillus flavus. The yeast was shown to significantly inhibit aflatoxin production and the growth of A. flavus. P. anomala is a potential biocontrol agent for reduction of aflatoxin in the food chain. Maintaining the viability of biocontrol agents in formulated products is a great challenge for commercial applications. Four media, NYG, NYGS, NYGT and NYGST are described which support good growth of yeast cells and were tested as storage formulations. Post growth supplement of 5 % trehalose to NYGST resulted in 83 % viable yeast cells after 12 months in cold storage. Intracellular sorbitol and trehalose concentrations were determined by HPLC analysis at the beginning of the storage and at the end of 12 month. Correlation of cell viability to both trehalose and sorbitol suggested a synergistic effect. Bonferroni (Dunn) t Test, Tukey's Studentized Range (HSD) Test and Duncan's Multiple Range Test, all showed that yeast cell viability in samples with both intracellular trehalose and sorbitol were significantly higher than those with either or none, at a 95 % confidence level. DiBAC4(5) and CFDA-AM were used as the membrane integrity fluorescent stains to create a two-color vital staining scheme with red and green fluorescence, respectively. Yeast cells stored in formulations NYG and NYGS with no detectable trehalose, displayed mostly red fluorescence. Yeast cells in NYGST+5T showed mostly green fluorescence.

  4. The transition from a phytopathogenic smut ancestor to an anamorphic biocontrol agent deciphered by comparative whole-genome analysis.

    Science.gov (United States)

    Lefebvre, François; Joly, David L; Labbé, Caroline; Teichmann, Beate; Linning, Rob; Belzile, François; Bakkeren, Guus; Bélanger, Richard R

    2013-06-01

    Pseudozyma flocculosa is related to the model plant pathogen Ustilago maydis yet is not a phytopathogen but rather a biocontrol agent of powdery mildews; this relationship makes it unique for the study of the evolution of plant pathogenicity factors. The P. flocculosa genome of ~23 Mb includes 6877 predicted protein coding genes. Genome features, including hallmarks of pathogenicity, are very similar in P. flocculosa and U. maydis, Sporisorium reilianum, and Ustilago hordei. Furthermore, P. flocculosa, a strict anamorph, revealed conserved and seemingly intact mating-type and meiosis loci typical of Ustilaginales. By contrast, we observed the loss of a specific subset of candidate secreted effector proteins reported to influence virulence in U. maydis as the singular divergence that could explain its nonpathogenic nature. These results suggest that P. flocculosa could have once been a virulent smut fungus that lost the specific effectors necessary for host compatibility. Interestingly, the biocontrol agent appears to have acquired genes encoding secreted proteins not found in the compared Ustilaginales, including necrosis-inducing-Phytophthora-protein- and Lysin-motif- containing proteins believed to have direct relevance to its lifestyle. The genome sequence should contribute to new insights into the subtle genetic differences that can lead to drastic changes in fungal pathogen lifestyles.

  5. Evidence for biotrophic lifestyle and biocontrol potential of dark septate endophyte Harpophora oryzae to rice blast disease.

    Directory of Open Access Journals (Sweden)

    Zhen-Zhu Su

    Full Text Available The mutualism pattern of the dark septate endophyte (DSE Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast.

  6. Phytic acid enhances biocontrol activity of Rhodotorula mucilaginosa against Penicillium expansum contamination and patulin production in apples

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    Qiya eYang

    2015-11-01

    Full Text Available The effect of Rhodotorula mucilaginosa in combination with phytic acid (PA on blue mold decay and patulin contamination of apples was investigated. Results from this study show that different concentrations of PA were effective in reducing the disease incidence of apples and that PA at concentration of 4 μmol/mL, decreased the incidence of blue mold decay in apples from 86.1% to 62.5%, and showed higher control efficacy compared to untreated, control fruit during storage at 20 °C. However, R. mucilaginosa combined with PA (4 μmol/mL showed better control efficacy of blue mold decay than R. mucilaginosa used as single treatment, the disease incidence was reduced to 62.5% and lesion diameter on apples was reduced to 16.59cm. In in vitro experiments, the addition of PA enhanced the biocontrol effect of R. mucilaginosa against the growth of P. expansum and reduced patulin level when compared with either R. mucilaginosa or PA used separately. R. mucilaginosa together with PA, improved the inhibition of patulin production in wounded apples, decreasing the content of patulin by 89.6% compared to the control, under experimental conditions. Both R. mucilaginosa and R. mucilaginosa in combination with PA degraded patulin in vitro. In conclusion, the appropriate combination of R. mucilaginosa and PA may provide an effective biocontrol method for reducing postharvest decay of apples.

  7. Phytic Acid Enhances Biocontrol Activity of Rhodotorula mucilaginosa against Penicillium expansum Contamination and Patulin Production in Apples.

    Science.gov (United States)

    Yang, Qiya; Zhang, Hongyin; Zhang, Xiaoyun; Zheng, Xiangfeng; Qian, Jingya

    2015-01-01

    The effect of Rhodotorula mucilaginosa in combination with phytic acid (PA) on blue mold decay and patulin contamination of apples was investigated. Results from this study show that different concentrations of PA were effective in reducing the disease incidence of apples and that PA at concentration of 4 μmol/mL, decreased the incidence of blue mold decay in apples from 86.1 to 62.5%, and showed higher control efficacy compared to untreated, control fruit during storage at 20°C. However, R. mucilaginosa combined with PA (4 μmol/mL) showed better control efficacy of blue mold decay than R. mucilaginosa used as single treatment, the disease incidence was reduced to 62.5% and lesion diameter on apples was reduced to 16.59 cm. In in vitro experiments, the addition of PA enhanced the biocontrol effect of R. mucilaginosa against the growth of Penicillium expansum and reduced patulin level when compared with either R. mucilaginosa or PA used separately. R. mucilaginosa together with PA, improved the inhibition of patulin production in wounded apples, decreasing the content of patulin by 89.6% compared to the control, under experimental conditions. Both R. mucilaginosa and R. mucilaginosa in combination with PA degraded patulin in vitro. In conclusion, the appropriate combination of R. mucilaginosa and PA may provide an effective biocontrol method for reducing postharvest decay of apples.

  8. POTENCY OF BIOCONTROL AGENTS ISOLATED FROM COMPOST AND PEAT SOIL OF TROPICAL PEAT SWAMP FOREST IN KALAMPANGAN ZONE, CENTRAL KALIMANTAN

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    Yuliar Yuliar

    2011-12-01

    Full Text Available Rhizoctonia solani is a soil pathogen that causes diseases in wide range of hosts of agricultural, horticultural and flower crops. Biological control is the most promising way for the diseases management and it is environment friendly too. The objective of this study was to isolate and screen the potency of soil bacteria as biological control from various local compost and peat soil of tropical peat swamp forest in Kalampangan Zone, Central Kalimantan. Forty seven isolates from peat soil and compost were screened for biocontrol agent of Rhizoctonia solani . R. Solani Seven out of thirteen peat soil isolates, and six out of thirty three compost isolates showed antagonistic activity against in Potato Dextrose Agar. The cultivation of the antagonistic isolates in Trypticase Soy Broth (TSB was extracted and analysed by high performance liquid chromatography (HPLC column. The HPLC analyzes indicated that the antagonistic isolates produce an antifungal iturin A. Macroscopic observation of isolates colonies showed that form of their colonies were amuboid, myceloid, curled, circular, rhizoid, irregular and filamentous. These achievement indicate peat swamp forest not only offer a potential biocontrol agents of damping off but also provide a new source for production of antibiotics.

  9. The S-adenosyl-L-homocysteine hydrolase gene ahcY of Agrobacterium radiobacter K84 is required for optimal growth, antibiotic production, and biocontrol of crown gall disease.

    Science.gov (United States)

    Penyalver, Ramón; Oger, Phil M; Su, Shengchang; Alvarez, Belén; Salcedo, Carmina I; López, María M; Farrand, Stephen K

    2009-06-01

    Agrobacterium radiobacter K84 is a commercial agent used worldwide to control crown gall disease caused by pathogenic isolates of A. tumefaciens. More than 2,000 transposon insertion derivatives of strain K84 were screened by a standardized greenhouse bioassay to identify mutants defective in biocontrol. Three mutants affected in biocontrol properties were identified. All three mutants displayed normal levels of attachment to tomato seed and root colonization. One of these mutants, M19-164, exhibited partial biocontrol and did not produce detectable levels of agrocin 84. In this mutant, the transposon is located in the agn locus of pAgK84, which codes for agrocin 84 biosynthesis. The second mutant, M19-158, also exhibited partial biocontrol and produced reduced amounts of agrocin 84 as a result of a mutation in a chromosomal gene of unknown function. The third mutant, M9-22, failed to biocontrol, was impaired in both growth in minimal medium and siderophore production, and failed to produce detectable levels of agrocin 84. The chromosomal gene ahcY, which encodes S-adenosyl-l-homocysteine hydrolase, was disrupted in this mutant. Expression of a functional copy of ahcY in M9-22 restored all of the altered phenotypes. The fact that all identified biocontrol mutants exhibited a partial or total defect in production of agrocin 84 indicates that this antibiotic is required for optimum biocontrol. This study also identified two chromosomally encoded genes required for agrocin 84 production. That a mutation in ahcY abolishes biocontrol suggests that the intracellular ratio of S-adenosyl-l-methionine to S-adenosyl-l-homocysteine is an important factor for agrocin 84 biosynthesis. Finally, we demonstrate that the ahcY gene in strain K84 is also required for optimal growth as well as for antibiotic production and biocontrol of crown gall disease.

  10. Response of tomato wilt pathogen Ralstonia solanacearum to the volatile organic compounds produced by a biocontrol strain Bacillus amyloliquefaciens SQR-9.

    Science.gov (United States)

    Raza, Waseem; Ling, Ning; Yang, Liudong; Huang, Qiwei; Shen, Qirong

    2016-04-22

    It is important to study the response of plant pathogens to the antibiosis traits of biocontrol microbes to design the efficient biocontrol strategies. In this study, we evaluated the role of volatile organic compounds (VOCs) produced by a biocontrol strain Bacillus amyloliquefaciens SQR-9 on the growth and virulence traits of tomato wilt pathogen Ralstonia solanacearum (RS). The VOCs of SQR-9 significantly inhibited the growth of RS on agar medium and in soil. In addition, the VOCs significantly inhibited the motility traits, production of antioxidant enzymes and exopolysaccharides, biofilm formation and tomato root colonization by RS. The strain SQR-9 produced 22 VOCs, but only nine VOCs showed 1-11% antibacterial activity against RS in their corresponding amounts; however, the consortium of all VOCs showed 70% growth inhibition of RS. The proteomics analysis showed that the VOCs of SQR-9 downregulated RS proteins related to the antioxidant activity, virulence, carbohydrate and amino acid metabolism, protein folding and translation, while the proteins involved in the ABC transporter system, amino acid synthesis, detoxification of aldehydes and ketones, methylation, protein translation and folding, and energy transfer were upregulated. This study describes the significance and effectiveness of VOCs produced by a biocontrol strain against tomato wilt pathogen.

  11. Regulation of aflatoxin biosynthesis and branched-chain amino acids metabolism in Aspergillus flavus by 2-phenylethanol reveal biocontrol mechanism of Pichia anomala

    Science.gov (United States)

    Pichia anomala WRL-076 is a biocontrol yeast which has been shown to inhibit growth and aflatoxin production of A. flavus. Using the SPME-GC/MS analysis we identified that the volatile, 2-phenylethanol (2-PE) produced by this yeast and demonstrated that the compound inhibited aflatoxin production. W...

  12. Biocontrol Potential of Lariophagus distinguendus (Hymenoptera: Pteromalidae) Against Sitophilus granarius (Coleoptera: Curculionidae) at Low Temperatures: Reproduction and Parasitoid-Induced Mortality

    DEFF Research Database (Denmark)

    Hansen, Lise Stengård

    2007-01-01

    , it amounted to 70% of the total mortality exerted by the parasitoid; at 18 and 16°C, it was 57 and 42% of the total, respectively. L. distinguendus is a promising biocontrol agent for grain stores in temperate regions because it is able to develop and reproduce at temperatures down to 16°C; its development...

  13. The phosphotransferase system gene ptsI in the endophytic bacterium Bacillus cereus is required for biofilm formation, colonization, and biocontrol against wheat sharp eyespot.

    Science.gov (United States)

    Xu, Yu-Bin; Chen, Mai; Zhang, Ying; Wang, Miao; Wang, Ying; Huang, Qiu-bin; Wang, Xue; Wang, Gang

    2014-05-01

    Natural resistance of wheat plants to wheat sharp eyespot is inadequate, and new strategies for controlling the disease are required. Biological control is an alternative and attractive way of reducing the use of chemicals in agriculture. In this study, we investigated the biocontrol properties of endophytic bacterium Bacillus cereus strain 0-9, which was isolated from the root systems of healthy wheat varieties. The phosphotransferase system is a major regulator of carbohydrate metabolism in bacteria. Enzyme I is one of the protein components of this system. Specific disruption and complementation of the enzyme I-coding gene ptsI from B. cereus was achieved through homologous recombination. Disruption of ptsI in B. cereus caused a 70% reduction in biofilm formation, a 30.4% decrease in biocontrol efficacy, and a 1000-fold reduction in colonization. The growth of ΔptsI mutant strain on G-tris synthetic medium containing glucose as the exclusive carbon source was also reduced. Wild-type properties could be restored to the ΔptsI mutant strain by ptsI complementation. These results suggested that ptsI may be one of the key genes involved in biofilm formation, colonization, and biocontrol of B. cereus and that B. cereus wild-type strain 0-9 may be an ideal biocontrol agent for controlling wheat sharp eyespot.

  14. Draft Genome Sequences of Pseudomonas fluorescens Strains SF39a and SF4c, Potential Plant Growth Promotion and Biocontrol Agents.

    Science.gov (United States)

    Ly, Lindsey K; Underwood, Grace E; McCully, Lucy M; Bitzer, Adam S; Godino, Agustina; Bucci, Vanni; Brigham, Christopher J; Príncipe, Analía; Fischer, Sonia E; Silby, Mark W

    2015-03-26

    Pseudomonas fluorescens SF4c and SF39a, strains isolated from wheat rhizosphere, have potential applications in plant growth promotion and biocontrol of fungal diseases of crop plants. We report the draft genome sequences of SF4c and SF39a with estimated sizes of 6.5 Mb and 5.9 Mb, respectively.

  15. Selection of a biocontrol agent based on a potential mechanism of action: degradation of nicotinic acid, a growth factor essential for Erwinia amylovora.

    Science.gov (United States)

    Paternoster, Thomas; Défago, Geneviève; Duffy, Brion; Gessler, Cesare; Pertot, Ilaria

    2010-12-01

    This work describes a medium-based screening method for selecting microbial biocontrol agents against Erwinia amylovora based on the degradation of a specific growth factor. Erwinia amylovora, the causal agent of the devastating fire blight disease, requires nicotinic acid or nicotinamide as an essential growth factor. Potential biocontrol agents are either selected for antimicrobial production in plate or directly on immature pears or apple blossoms. In this work, we have attempted to streamline the selection of a new potential biocontrol agent with a lower risk of non-target effects by isolation based on the ability to degrade nicotinic acid in vitro, using therefore few plant materials. A total of 735 bacteria and 1237 yeast were isolated from apple blossoms and pre-screened for nicotinic acid-degradation. Pseudomonas rhizosphaerae strain JAN was able to degrade both nicotinic acid and nicotinamide. Mutants deficient in this ability were constructed. JAN, but not the mutants, controlled E. amylovora on pear slices. On detached apple blossoms, JAN colonized apple hypanthia and strongly suppressed E. amylovora growth. Under greenhouse conditions, JAN was more effective in controlling blossom blight than P. fluorescens A506, a commercial biocontrol agent of fire blight unable to degrade nicotinic acid and nicotinamide.

  16. Polysaccharide Production Benefits Dry Storage Survival of the Biocontrol Agent Pseudomonas fluorescens S11:P:12 Effective Against Several Maladies of Stored Potatoes

    Science.gov (United States)

    Pseudomonas fluorescens S11:P:12 (NRRL B-21133) is a biological control agent able to suppress several potato diseases and sprouting. Notably, it produces a polysaccharide during liquid cultivation; and the objective of this work was to determine the role of this material in the bio-control process...

  17. Role of 2-hexyl, 5-propyl resorcinol production by Pseudomonas chlororaphis PCL1606 in the multitrophic interactions in the avocado rhizosphere during the biocontrol process.

    Science.gov (United States)

    Calderón, Claudia E; de Vicente, Antonio; Cazorla, Francisco M

    2014-07-01

    Different bacterial traits can contribute to the biocontrol of soilborne phytopathogenic fungus. Among others, (1) antagonism, (2) competition for nutrients and niches, (3) induction of systemic resistance of the plants and (4) predation and parasitism are the most studied. Pseudomonas chlororaphis PCL1606 is an antagonistic rhizobacterium that produces the antifungal metabolite 2-hexyl, 5-propyl resorcinol (HPR). This bacterium can biologically control the avocado white root rot caused by Rosellinia necatrix. Confocal laser scanning microscopy of the avocado rhizosphere revealed that this biocontrol bacterium and the fungal pathogen compete for the same niche and presumably also for root exudate nutrients. The use of derivative mutants in the geners related to HPR biosynthesis (dar genes) revealed that the lack of HPR production by P. chlororaphis PCL1606 negatively influences the bacterial colonisation of the avocado root surface. Microscopical analysis showed that P. chlororaphis PCL1606 closely interacts and colonises the fungal hyphae, which may represent a novel biocontrol mechanism in this pseudomonad. Additionally, the presence of HPR-producing biocontrol bacteria negatively affects the ability of the fungi to infect the avocado root. HPR production negatively affects hyphal growth, leading to alterations in the R. necatrix physiology visible under microscopy, including the curling, vacuolisation and branching of hyphae, which presumably affects the colonisation and infection abilities of the fungus. This study provides the first report of multitrophic interactions in the avocado rhizosphere, advancing our understanding of the role of HPR production in those interactions.

  18. RNA interference of endochitinases in the sugarcane endophyte Trichoderma virens 223 reduces its fitness as a biocontrol agent of pineapple disease.

    Directory of Open Access Journals (Sweden)

    Aline S Romão-Dumaresq

    Full Text Available The sugarcane root endophyte Trichoderma virens 223 holds enormous potential as a sustainable alternative to chemical pesticides in the control of sugarcane diseases. Its efficacy as a biocontrol agent is thought to be associated with its production of chitinase enzymes, including N-acetyl-ß-D-glucosaminidases, chitobiosidases and endochitinases. We used targeted gene deletion and RNA-dependent gene silencing strategies to disrupt N-acetyl-ß-D-glucosaminidase and endochitinase activities of the fungus, and to determine their roles in the biocontrol of soil-borne plant pathogens. The loss of N-acetyl-ß-D-glucosaminidase activities was dispensable for biocontrol of the plurivorous damping-off pathogens Rhizoctonia solani and Sclerotinia sclerotiorum, and of the sugarcane pathogen Ceratocystis paradoxa, the causal agent of pineapple disease. Similarly, suppression of endochitinase activities had no effect on R. solani and S. sclerotiorum disease control, but had a pronounced effect on the ability of T. virens 223 to control pineapple disease. Our work demonstrates a critical requirement for T. virens 223 endochitinase activity in the biocontrol of C. paradoxa sugarcane disease, but not for general antagonism of other soil pathogens. This may reflect its lifestyle as a sugarcane root endophyte.

  19. Superoxide anion and hydrogen peroxide in the yeast antagonist-fruit interaction: a new role for reactive oxygen species in postharvest biocontrol?

    Science.gov (United States)

    The importance of reactive oxygen species (ROS) in plant defense responses against certain pathogens is well documented. There is some evidence that microbial biocontrol agents also induce a transient production of ROS in a host plant which triggers local and systemic defense responses to pathogens....

  20. Use of Hypocrea jecorina (anamorph Trichoderma reesei) as a model system for Trichoderma biocontrol of Pythium blight identifies new targets for genetic strain improvement

    Institute of Scientific and Technical Information of China (English)

    Seidl V; Schmoll M; Scherm B; Balmas V; Seiboth B; Migheli Q; Kubicek C P

    2004-01-01

    @@ Biocontrol by Trichoderma has been studied mainly with selected isolates of T. harzianum, T.atroviride and T. asperellum, which are members of sections Pachybasium and Trichoderma. In contrast, species from section Longibrachiatum have only rarely been studied. On the other hand, one taxon from this section-Hypocrea jecorina (anamorph: Trichoderma reesei)-has been widely used for the production of cellulolytic and hemicellulolytic enzymes and recombinant proteins. As far as Trichoderma is concerned, molecular genetic methods and tools are most advanced in H. jecorina,and its genome has recently been fully sequenced, thus making this taxon a model organism for the genus. Here we will demonstrate that H. jecorina is able to antagonize plant pathogenic fungi in plate confrontation tests, and can protect tomato and cucumber plants against Pythium ultimum blight.Using this as a model case, we made use of available H. jecorina mutants to investigate (a) whether carbon catabolite repression via the Cre1-regulator protein has an impact on biocontrol, and (b)whether cellulase gene expression is necessary for biocontrol of P. ultimum. In the first case, plate confrontation tests and in planta experiments yielded opposite results, i.e. while a Cre1 mutant was more active in antagonization of fungi on plates, the survival rates of P. ultimum-inoculated cucumber plants was lower than with the H. jecorina wild-type strain. Mutants of H. jecorina,unable to form cellulases, were still able to antagonize fungi on plates and provided similar protection of tomatos against P. ultimum as the wild type, indicating that the pronounced biocontrol ability of H.jecorina against fungi with cellulose-containing cell-walls is not due to its high cellulolytic activity. A strain disrupted in the light-modulator gene envoy (Schmoll et al., ms submitted) exhibited in planta biocontrol activity strongly exceeding that of the wild-type strain, thereby providing a first link between Trichoderma

  1. Towards understanding the ecology and mechanisms of biocontrol of Clonostachys rosea IK726

    Institute of Scientific and Technical Information of China (English)

    Mette Lübeck; Inge M B Knudsen; Birgit Jensen; Mojtaba Mamarabadi; Dan Funck Jensen

    2004-01-01

    @@ Clonostachys rosea (syn. Gliocladium roseum ) IK726 was originally selected as an effective biocontrol agent (BCA) against cereal seed borne diseases caused by Fusarium culmorum and Bipolaris sorokiniana. We have studied the efficacy of the antagonist against different pathogens in several crops and found that the antagonist also is able to control Alternaria radicina and A. dauci on carrot seeds and different cold-storage fungi in acorns. IK726 is also able to reduce severity of soil borne Pythium spp. in cabbage, carrot and sugar beet. In addition, growth-promoting effects of IK726 have been demonstrated in barley and tomato. In order to develop and improve application methods and control strategies, essential basic studies of ecology and the mechanisms of control of IK726 is needed and has led us to use various molecular tools. The UP-PCR technology is used for strain recognition and we have developed GUS and GFP-transformants that resembles the wildtype strain in ecological fitness parameters. Using either the GUS-transformant or UP-PCR we have found that IK726, when applied with seeds, reproduces and survives several months in the rhizosphere of field grown barley and carrot.The GFP-transformant is used to study the behavior and in situ interactions of the antagonist with pathogens and plants. Using the GFP marker, we have observed conidial germination, colonization and conidiogenesis in natural soil, in vermiculite and on carrot and barley seed and roots and on barley leaves. Moreover in situ interactions with Alternaria on carrot material have been studied. The modes of action of C. rosea are not well understood but enzymatic activity, mycoparasitism, substrate competition, antibiosis and induced resistance are thought to play a role. Barley treated with C. rosea IK726 has an enhanced chitinolytic and glucanolytic activity compared to the activity in non-treated barley in pot experiments with field soil. Identification of chitinases from IK726 and studies

  2. What magnitude are observed non-target impacts from weed biocontrol?

    Directory of Open Access Journals (Sweden)

    David Maxwell Suckling

    Full Text Available A systematic review focused by plant on non-target impacts from agents deliberately introduced for the biological control of weeds found significant non-target impacts to be rare. The magnitude of direct impact of 43 biocontrol agents on 140 non-target plants was retrospectively categorized using a risk management framework for ecological impacts of invasive species (minimal, minor, moderate, major, massive. The vast majority of agents introduced for classical biological control of weeds (>99% of 512 agents released have had no known significant adverse effects on non-target plants thus far; major effects suppressing non-target plant populations could be expected to be detectable. Most direct non-target impacts on plants (91.6% were categorized as minimal or minor in magnitude with no known adverse long-term impact on non-target plant populations, but a few cacti and thistles are affected at moderate (n = 3, major (n = 7 to massive (n = 1 scale. The largest direct impacts are from two agents (Cactoblastis cactorum on native cacti and Rhinocyllus conicus on native thistles, but these introductions would not be permitted today as more balanced attitudes exist to plant biodiversity, driven by both society and the scientific community. Our analysis shows (as far as is known, weed biological control agents have a biosafety track record of >99% of cases avoiding significant non-target impacts on plant populations. Some impacts could have been overlooked, but this seems unlikely to change the basic distribution of very limited adverse effects. Fewer non-target impacts can be expected in future because of improved science and incorporation of wider values. Failure to use biological control represents a significant opportunity cost from the certainty of ongoing adverse impacts from invasive weeds. It is recommended that a simple five-step scale be used to better communicate the risk of consequences from both action (classical biological

  3. Theoretical modeling suggests that synergy may result from combined use of two biocontrol agents for controlling foliar pathogens under spatial heterogeneous conditions.

    Science.gov (United States)

    Xu, X-M; Jeger, M J

    2013-08-01

    There has been a trend for combined use of several biocontrol agents (BCAs) with an expectation of synergistic interactions among BCAs. However, previous modeling studies suggested that, under homogeneous and temporal-fluctuating conditions, combined use of two BCAs, in most cases, only results in efficacies similar to the more efficacious one used alone; a result consistent with published experimental data. The present modeling study investigated whether combined use of two mycoparasitic BCAs, two competitive BCAs, or a mycoparasitic and a competitive BCA leads to synergistic interactions under spatially heterogeneous conditions. In the model, there were two patches with varying relative sizes and two BCAs differentially adapted to the two patches. Within the range of model parameter values considered, combined use of two BCAs is more effective than the more efficacious BCA used alone in 72% of the simulated cases. There was also a considerable proportion (≈21%) of model simulations in which combined use of two BCAs led to synergy (i.e., efficacy was greater than expected under the assumption of Bliss independence, especially when each of the two BCAs can only survive in one [different] patch). Combined use of a mycoparasitic BCA with a competitive one is more likely to result in synergy than the other two BCA combinations. When biocontrol activities of individual BCAs are low or moderate, biocontrol efficacy arising from combined use of two BCAs does not depend greatly on biocontrol mechanisms. However, for high BCA activities, combined use with at least one competitive BCA resulted in better control than combined use of two mycoparasitic BCAs. The present modeling study emphasized the need for understanding the degree of spatial patchiness and quantitative relationships between biocontrol activities and external conditions in order to apply commercial BCAs effectively.

  4. STUDIES ON SELECTIVE TOXICITY OF SIX INSECTICIDES BETWEEN GREEN PEACH APHID AND LADYBIRDS%几种药剂对桃蚜和两种瓢虫的毒力选择性研究

    Institute of Scientific and Technical Information of China (English)

    薛明; 李强

    2002-01-01

    在室内分别测定了吡虫啉、吡虫啉+增效剂、氰戊菊酯、硫丹、乐果和灭多威6种杀虫剂对桃蚜Myzus persicae Sul-zer、七星瓢虫Coccinella septempunctata Linnaeus和龟纹瓢虫Propyleajaponica(Thunbery)的毒力;比较了药剂在桃蚜和两种瓢虫之间的选择毒力比值(STR),以及药剂之间选择性差异;研究了桃蚜对不同药剂相对适合度.结果表明:吡虫啉+增效剂(SV1)和吡虫啉对桃蚜的毒力均很高,LC50分别是0.4628 mg/L和0.9535 mg/L.吡虫啉在七星瓢虫和桃蚜之间、龟纹瓢虫和桃蚜之间的STR值分别是37.6和13.0,吡虫啉+增效剂的STR分别是9.84和7.75,硫丹的SR分别是54.0和7.28,都表现出显著的毒力选择性.而氰戊菊酯、乐果和灭多威的STR值均很小(0.02~0.21),不仅对桃蚜毒力低,而且对两种瓢虫也不安全.用吡虫啉和吡虫啉+SV1的LC50浓度处理桃蚜,其存活个体的产仔率和单雌产仔量明显减少,与其它药剂处理相比,显著降低了桃蚜的相对适合度.六种杀虫剂处理的桃蚜种群,其相对适合度大小排列为:乐果EC(0.92)>氰戊菊酯EC(0.67)>灭多威EC(0.66)>硫丹EC(0.51)>吡虫啉WP(0.40)>吡虫啉+增效剂(SV1)EC(0.18).由此证明,吡虫啉不仅对桃蚜毒力高,对天敌瓢虫杀伤力小,而且对桃蚜种群有持续控制作用.%The selective toxicity of six kinds of insecticides, including imidacloprid, imidacloprid + synergist (SV1), fenvaler-ate, endosulfan, methomyl and dimaethoate, between the green peach aphid ( Myzus persicae Sulzer) and two species of ladybirds( Coccinella septempunctata Linnaeus and Propylaea japonica Th unbery), was investigated in the laboratory. The results showed thatboth imidacloprid WP and imidacloprid + synergist (SV1) EC possessed the highest toxicity to the aphids. Between C. septempunc-tata and M. persicae and between P. japonica and M. persicae, the selective toxicity ratios (STRs) of imidacloprid WP, imidaclo-prid+ synergist (SV1) EC

  5. Combinative effects of a bacterial type-III effector and a biocontrol bacterium on rice growth and disease resistance

    Indian Academy of Sciences (India)

    Haiying Ren; Ganyu Gu; Juying Long; Qian Yin; Tingquan Wu; Tao Song; Shujian Zhang; Zhiyi Chen; Hansong Dong

    2006-12-01

    Expression of HpaGXoo, a bacterial type-III effector, in transgenic plants induces disease resistance. Resistance also can be elicited by biocontrol bacteria. In both cases, plant growth is often promoted. Here we address whether biocontrol bacteria and HpaGXoo can act together to provide better results in crop improvement. We studied effects of Pseudomonas cepacia on the rice variety R109 and the hpaGXoo-expressing rice line HER1. Compared to R109, HER1 showed increased growth, grain yield, and defense responses toward diseases and salinity stress. Colonization of roots by P. cepacia caused 20% and 13% increase, in contrast to controls, in root growth of R109 and HER1. Growth of leaves and stems also increased in R109 but that of HER1 was inhibited. When P. cepacia colonization was subsequent to plant inoculation with Rhizoctonia solani, a pathogen that causes sheath blight, the disease was less severe than controls in both R109 and HER1; HER1, nevertheless, was more resistant, suggesting that P. cepacia and HpaGXoo cooperate in inducing disease resistance. Several genes that critically regulate growth and defense behaved differentially in HER1 and R109 while responding to P. cepacia. In R109 leaves, the OsARF1 gene, which regulates plant growth, was expressed in consistence with growth promotion by P. cepacia. Inversely, OsARF1 expression was coincident with inhibition in growth of HER1 leaves. In both plants, the expression of OsEXP1, which encodes an expansin protein involved in plant growth, was concomitant with growth promotion in leaves instead of roots, in response to P. cepacia. We also studied OsMAPK, a gene that encodes a mitogen-activated protein kinase and controls defense responses toward salinity and infection by pathogens in rice. In response to P. cepacia, an early expression of OsMAPK was coincident with R109 resistance to the disease, while HER1 expressed the gene similarly whether P. cepacia was present or not. Evidently, P. cepacia and GXoo

  6. Identification of Volatile Metabolites from Fungal Endophytes with Biocontrol Potential towards Fusarium oxysporum F. sp. cubense Race 4

    Directory of Open Access Journals (Sweden)

    A. S. Y. Ting

    2010-01-01

    Full Text Available Problem statement: Fungal endophytes are widely studied for their potential as biocontrol agents towards fungal pathogens. In vitro assessments usually reveal their antibiosis and mycoparasitism nature, but little is understood regarding their production of volatile metabolites as mechanisms of antagonism. Approach: This study explored the potential of fungal endophytes in controlling the pathogen responsible for Fusarium wilt disease. Nine fungal endophytes were tested for their ability to inhibit the growth of the pathogenic Fusarium oxysporum F. sp. cubense race 4 (FocR4 via production of volatile inhibitory metabolites. The type of volatile metabolites produced were subsequently characterized and identified using the Gas-Chromatography Mass-Spectrophotometry (GCMS. Results: Eight of the isolates (BTF05, BTF07, BTF08, BTF15, BTF21, WAA03, WAA02, MIF01 showed positive results with percentages of inhibition varying from 1.43-31.43% while one isolate (ALF01, showed negative result (0% inhibition. Volatile profiles showed that these fungal endophytes produced between 15-47 volatile metabolites per isolate. However, the more volatile metabolites produced by a single endophyte does not indicate better biocontrol potential. Isolate BTF05 produced 47 different volatile metabolites, but has only 8.57% inhibition, compared to isolate BTF21 with 15 metabolites but a percentage of 11.43% inhibition. The potency of the volatile metabolites produced may also influenced the biocontrol potential of the fungal endophytes as some isolates such as BTF08 and MIF01 have only two to three known inhibitory metabolites but have higher PIDG values at 31.43 and 11.43%, respectively. Contrary, isolates WAA02 and WAA03 which has five to six metabolites but PIDG values of less than 3%. Conclusion: Fungal endophytes have the ability to produce several types of volatile metabolites to inhibit the growth of FocR4. These volatile inhibitory metabolites can be further

  7. Characterization of streptomycetes with potential to promote plant growth and biocontrol Caracterização de estreptomicetos com potencial para promoção de crescimento de plantas e biocontrole

    Directory of Open Access Journals (Sweden)

    Carla da Silva Sousa

    2008-02-01

    Full Text Available Studies with streptomycetes in biocontrol programs and plant growth promotion are presented as technological alternatives for environmental sustainable production. This work has the objective of characterizing six isolates of streptomycetes aiming the production of extracellular enzymes, indole acetic acid, capacity for phosphate solubilization, root colonization and growth under different pH and salinity levels. For detection of enzyme activity the isolates were grown in culture media with the enzyme substrates as sole carbon source. The root colonization assay was performed on tomato seedlings grown on 0.6% water-agar medium. Growth under different pH and salinity levels was evaluated in AGS medium with 1%, 1.5%, 2%, 2.5%, and 3% NaCl, and pH levels adjusted to 5.0, 5.5, 6.0, 6.5, and 7.0. All isolates produced the enzymes amylase, catalase, and lipase, as well as indole acetic acid. With one exception (AC-92, all isolates presented cellulolytic and chitinolytic activity, and only AC-26 did not show xylanolytic activity. The isolates AC-147, AC-95, and AC-29 were the highest producers of siderophores. The isolates AC-26 and AC-29 did not show capacity for phosphate solubilization. All isolates colonized tomato roots in vitro, and AC-92 grew under all pH and salinity levels tested. The streptomycetes tested were considered as potential biocontrol and plant growth promotion agents.Estudos com estreptomicetos em programas de biocontrole e promoção de crescimento de plantas são alternativas tecnológicas de produção sustentáveis ao ambiente. O presente trabalho teve como objetivo caracterizar seis isolados de estreptomicetos quanto à produção de enzimas extracelulares, ácido indolacético e sideróforos, capacidade de solubilização de fosfatos, colonização radicular e de crescimento em diferentes níveis de pH e salinidade. Para detectar a produção das enzimas extracelulares, os isolados foram cultivados em meio de cultura contendo

  8. 不同玉米品种对玉米蚜的抗性及其与瓢虫的联合控害作用%Resistance to corn aphid (Rhopalosiphum maidis Fitch) of different corn varieties (lines) and its association with predator ladybirds in controlling aphid population

    Institute of Scientific and Technical Information of China (English)

    张衍干; 黄吉; 施伟迪; 王碧媛; 贾永超; 禹田; 李强

    2016-01-01

    调查了26个玉米品种(系)在云南昭通地区的玉米蚜及其捕食型天敌瓢虫的发生情况,采用蚜量比值法比较了玉米品种在田间对玉米蚜的抗性,并分析了不同玉米品种的抗蚜性与益害比(瓢虫/玉米蚜)的关系。结果表明:在田间自然感蚜条件下,高抗品种有9个,分别为路单15号、胜玉6号、云瑞62、靖单11号、云瑞339、云瑞407、云瑞668、云瑞89、云瑞7号;抗性品种6个,分别为云瑞392、云瑞222、临玉9号、云瑞999、云瑞10号、云瑞505;中抗品种1个,为珍禾99;感蚜品种4个,分别为云瑞666、足单808、宣黄单5号、临玉8号;高感品种6个,分别为临玉10号(白粒)、大天一号、海玉92、宣黄单2号、云瑞108、师单4号。不同玉米品种的抗蚜性与益害比有显著的正相关性,益害比与蚜量比值呈幂函数关系,说明玉米的抗蚜性与瓢虫对玉米蚜有明显的联合控制作用。%The dynamics of corn aphid ( Rhopalosiphum maidis Fitch) and predator ladybirds in 26 corn varieties (lines) were systematically investigated in Zhaotong , Yunnan Province, to compare their resistance to aphid among varieties in corn field by using the methods of aphid number ratio , and to study the relationship between resistance and the population ratio of ladybirds to aphid in different corn varieties .The results indicated that there were 9 highly resistant varieties (Ludan 15, Shengyu 6, Yunrui 62, Jingdan 11, Yunrui 339, Yunrui 407, Yunrui 668, Yunrui 89, Yunrui 7), 6 resistant varieties (Yunrui 392, Yunrui 222, Linyu 9, Yunrui 999, Yunrui 10, Yunrui 505), 1 moderately resistant varieties (Zhenhe 99), 4 susceptible varieties (Yunrui 666, Zudan 808, Xuanhuangdan 5, Linyu 8), and 6 highly susceptible varieties [Linyu 10 (white), Datian 1, Haiyu 92, Xuanhuangdan 2, Yunrui 108, Shidan 4].Among the above 26 varieties, the variety with high resistance tended to have high ratio of

  9. Biocontrol of Botrytis allii Munn the Causal Agent of Neck Rot, the Post Harvest Disease in Onion, by use of a New Iranian Isolate of Streptomyces

    OpenAIRE

    Jorjandi, M.; G. H.S. Bonjar; A. Baghizadeh; G. R. S. Sirchi; H. Massumi; F. Baniasadi; S. Aghighi; P. R. Farokhi

    2009-01-01

    Problem statement: Soil actinomycetes particularly Streptomyces spp. showed antagonistic activity against wide range of plant pathogens. In the recent decades they have attracted high interests as biocontrol agents. Onion neck rot or gray mold caused by Botrytis allii have imposed economic post harvest damages to onion bulbs and decreased its storage durability and market value. Approach: To investigate for biocontrol means against the pathogen, antagonisti...

  10. Complete genome sequence of Bacillus velezensis M75, a biocontrol agent against fungal plant pathogens, isolated from cotton waste.

    Science.gov (United States)

    Kim, Sang Yoon; Lee, Sang Yeob; Weon, Hang-Yeon; Sang, Mee Kyung; Song, Jaekyeong

    2017-01-10

    Bacillus species have been widely used as biological control agents in agricultural fields due to their ability to suppress plant pathogens. Bacillus velezensis M75 was isolated from cotton waste used for mushroom cultivation in Korea, and was found to be antagonistic to fungal plant pathogens. Here, we report the complete genome sequence of the M75 strain, which has a 4,007,450-bp single circular chromosome with 3921 genes and a G+C content of 46.60%. The genome contained operons encoding various non-ribosomal peptide synthetases and polyketide synthases, which are responsible for the biosynthesis of secondary metabolites. Our results will provide a better understanding of the genome of B. velezensis strains for their application as biocontrol agents against fungal plant pathogens in agricultural fields.

  11. Yeasts from native Brazilian Cerrado plants: Occurrence, diversity and use in the biocontrol of citrus green mould.

    Science.gov (United States)

    Sperandio, Eugenio Miranda; do Vale, Helson Mario Martins; Moreira, Geisianny Augusta Monteiro

    2015-11-01

    Yeasts are some of the most important postharvest biocontrol agents. Postharvest oranges frequently deteriorate due to green mould (Penicillium digitatum), which causes significant losses. The aims of this study were to determine the composition and diversity of yeasts on plants of the Brazilian Cerrado and to explore their potential for inhibiting citrus green mould. Leaves and fruit of Byrsonima crassifolia and Eugenia dysenterica were collected from Cerrado conservation areas, and thirty-five yeasts were isolated and identified by sequencing the D1-D2 domain of the rDNA large subunit (26S). The isolates represented the Aureobasidium, Meyerozyma, Candida, and Pichia genera. Three isolates identified as Aureobasidium pullulans exhibited potential for the control of P. digitatum in both in vitro and in vivo tests; these isolates reduced the incidence of disease and increased the storage time of fruit. Aureobasidium. pullulans has immense potential for the biological control of filamentous fungi.

  12. Identification of Volatiles Produced by Cladosporium cladosporioides CL-1, a Fungal Biocontrol Agent That Promotes Plant Growth

    Directory of Open Access Journals (Sweden)

    Diby Paul

    2013-10-01

    Full Text Available Certain microbial Volatile Organic Compounds (VOCs have been reported to enhance the growth and development of plants. The biocontrol fungi, Cladosporium cladosporioides CL-1 significantly improved the growth of tobacco seedlings in vitro when they were co-cultivated without physical contact. SPME Quadrupole GC/MS/MS revealed that CL-1 emited the volatiles α-pinene, (−-trans-caryophyllene, tetrahydro-2,2,5,5-tetramethylfuran, dehydroaromadendrene, and (+-sativene. Potential roles of these volatiles in plant growth and development are discussed. Even though there were several fungal VOCs reported in the past that could influence plant growth, their exact mechanisms of action are not fully known. Fungal VOC-mediated plant growth promotion requires in-depth study in order for this technology to be used in large scale for crops, especially those grown under greenhouse conditions.

  13. Identification of volatiles produced by Cladosporium cladosporioides CL-1, a fungal biocontrol agent that promotes plant growth.

    Science.gov (United States)

    Paul, Diby; Park, Kyung Seok

    2013-10-16

    Certain microbial Volatile Organic Compounds (VOCs) have been reported to enhance the growth and development of plants. The biocontrol fungi, Cladosporium cladosporioides CL-1 significantly improved the growth of tobacco seedlings in vitro when they were co-cultivated without physical contact. SPME Quadrupole GC/MS/MS revealed that CL-1 emited the volatiles α-pinene, (-)-trans-caryophyllene, tetrahydro-2,2,5,5-tetramethylfuran, dehydroaromadendrene, and (+)-sativene. Potential roles of these volatiles in plant growth and development are discussed. Even though there were several fungal VOCs reported in the past that could influence plant growth, their exact mechanisms of action are not fully known. Fungal VOC-mediated plant growth promotion requires in-depth study in order for this technology to be used in large scale for crops, especially those grown under greenhouse conditions.

  14. Antagonistic and Biocontrol Potential of Trichoderma asperellum ZJSX5003 Against the Maize Stalk Rot Pathogen Fusarium graminearum.

    Science.gov (United States)

    Li, Yaqian; Sun, Ruiyan; Yu, Jia; Saravanakumar, Kandasamy; Chen, Jie

    2016-09-01

    The efficacy of seven strains of Trichoderma asperellum collected from the fields in Southern China was assessed against Fusarium graminearum (FG) the causal agent of corn stalk rot of maize were in vitro for their antagonistic properties followed by statistical model of principal compound analysis to identify the beneficial antagonist T. asperellum strain. The key factors of antagonist activity were attributed to a total of 13 factors including cell wall degrading enzymes (chitnase, protease and β-glucanases), secondary metabolites and peptaibols and these were analyzed from eight strains of Trichoderma. A linear regression model demonstrated that interaction of enzymes and secondary metabolites of T. asperellum strain ZJSX5003 enhanced the antagonist activity against FG. Further, this strain displayed a disease reduction of 71 % in maize plants inoculated with FG compared to negative control. Pointing out that the T. asperellum strain ZJSX5003 is a potential source for the development of a biocontrol agent against corn stalk rot.

  15. Biocontrol of Postharvest Anthracnose of Mango Fruit with Debaryomyces Nepalensis and Effects on Storage Quality and Postharvest Physiology.

    Science.gov (United States)

    Luo, Shanshan; Wan, Bin; Feng, Shuhan; Shao, Yuanzhi

    2015-11-01

    Anthracnose is presently recognized as one of the most important postharvest disease of mango worldwide. To control the disease, chemical fungicides for a long time was widely used among fruit farmers, but recently found that pathogen had developed increasingly resistance to it. With people's growing desire of healthy and green food, finding new and environmentally friendly biological control approach was very necessary. In this paper, we provided a kind of new antagonistic yeast which enriched the strain resources and the efficacy of Debaryomyces nepalensis against postharvest anthracnose of mango fruit and the influence on quality parameters were investigated. The results showed that the decay incidence and lesion diameter of postharvest anthracnose of mango treated by D. nepalensis were significantly reduced compared with the control fruit stored at 25 °C for 30 d or at 15 °C for 40 d, and the higher concentration of D. nepalensis was, the better the efficacy of the biocontrol was. Study also found that 1 h was the best treatment duration and antagonistic yeast inoculated earlier had good biocontrol effect on anthracnose. Meanwhile, treatment by D. nepalensis could significantly reduce postharvest anthracnose of mango, delay the decrease in firmness, TSS, TA, and ascorbic acid value, and do not impair surface color during postharvest storage. Moreover, the increase in MDA (malondialdehyde) content and increase in cell membrane permeability of fruit treated by D. nepalensis was highly inhibited. The results suggested D. nepalensis treatment could not only maintain storage quality of mango fruit, but also decrease the decay incidence to anthracnose disease. All these results indicated that D. nepalensis has great potential for development of commercial formulations to control postharvest pathogens of mango fruit.

  16. Colonization pattern of the biocontrol strain Pseudomonas chlororaphis MA 342 on barley seeds visualized by using green fluorescent protein.

    Science.gov (United States)

    Tombolini, R; van der Gaag, D J; Gerhardson, B; Jansson, J K

    1999-08-01

    Pseudomonas chlororaphis MA 342 is a potent biocontrol agent that can be used against several seed-borne diseases of cereal crops, including net blotch of barley caused by the fungus Drechslera teres. In this study, strain MA 342 was tagged with the gfp gene (encoding the green fluorescent protein) in order to study the fate of cells after seed inoculation. The gfp-tagged strain, MA 342G2, had the same biocontrol efficacy as the wild type when it was applied at high cell concentrations to seeds but was less effective at lower cell concentrations. By comparing cell counts determined by microscopy to the number of CFU, we found that the number of culturable cells was significantly lower than the total number of bacteria on seeds which were inoculated and dried for 20 h. Confocal microscopy and epifluorescence stereomicroscopy were used to determine the pattern of MA 342G2 colonization and cell aggregation on barley seeds. Immediately after inoculation of seeds, bacteria were found mainly under the seed glume, and there was no particular aggregation pattern. However, after the seeds were sown, irregularly distributed areas of bacterial aggregation were found, which reflected epiphytic colonization of glume cells. There was a trend towards bacterial aggregation near the embryo but never within the embryo. Bacterial aggregates were regularly found in the groove of each seed formed by the base of the coleoptile and the scutellum. Based on these results, we suggest that MA 342 colocalizes with the pathogen D. teres, which facilitates the action of the fungistatic compound(s) produced by this strain.

  17. Bacillus amyloliquefaciens GA1 as a source of potent antibiotics and other secondary metabolites for biocontrol of plant pathogens

    Directory of Open Access Journals (Sweden)

    Brans Alain

    2009-11-01

    Full Text Available Abstract Background Phytopathogenic fungi affecting crop and post-harvested vegetables are a major threat to food production and food storage. To face these drawbacks, producers have become increasingly dependent on agrochemicals. However, intensive use of these compounds has led to the emergence of pathogen resistance and severe negative environmental impacts. There are also a number of plant diseases for which chemical solutions are ineffective or non-existent as well as an increasing demand by consumers for pesticide-free food. Thus, biological control through the use of natural antagonistic microorganisms has emerged as a promising alternative to chemical pesticides for more rational and safe crop management. Results The genome of the plant-associated B. amyloliquefaciens GA1 was sample sequenced. Several gene clusters involved in the synthesis of biocontrol agents were detected. Four gene clusters were shown to direct the synthesis of the cyclic lipopeptides surfactin, iturin A and fengycin as well as the iron-siderophore bacillibactin. Beside these non-ribosomaly synthetised peptides, three additional gene clusters directing the synthesis of the antibacterial polyketides macrolactin, bacillaene and difficidin were identified. Mass spectrometry analysis of culture supernatants led to the identification of these secondary metabolites, hence demonstrating that the corresponding biosynthetic gene clusters are functional in strain GA1. In addition, genes encoding enzymes involved in synthesis and export of the dipeptide antibiotic bacilysin were highlighted. However, only its chlorinated derivative, chlorotetaine, could be detected in culture supernatants. On the contrary, genes involved in ribosome-dependent synthesis of bacteriocin and other antibiotic peptides were not detected as compared to the reference strain B. amyloliquefaciens FZB42. Conclusion The production of all of these antibiotic compounds highlights B. amyloliquefaciens GA1 as

  18. The biocontrol endophytic bacterium Pseudomonas fluorescens PICF7 induces systemic defense responses in aerial tissues upon colonization of olive roots

    Directory of Open Access Journals (Sweden)

    Carmen eGómez-Lama Cabanás

    2014-09-01

    Full Text Available Pseudomonas fluorescens PICF7, a native olive root endophyte and effective biocontrol agent (BCA against Verticillium wilt of olive, is able to trigger a broad range of defense responses in root tissues of this woody plant. In order to elucidate whether strain PICF7 also induces systemic defense responses in above-ground organs, aerial tissues of olive plants grown under non-gnotobiotic conditions were collected at different time points after root bacterization with this endophytic BCA. A suppression subtractive hybridization (SSH cDNA library, enriched in up-regulated genes, was generated. This strategy enabled the identification of 376 ESTs (99 contigs and 277 singlets, many of them related to response to different stresses. Five ESTs, involved in defense responses, were selected to carry out time-course quantitative real-time PCR (qRT-PCR experiments aiming to: (i validate the induction of these genes, and (ii shed light on their expression pattern along time (from 1 to 15 days. Induction of olive genes potentially coding for lypoxigenase 2, catalase, 1-aminocyclopropane-1-carboxylate oxidase and phenylananine ammonia-lyase was thus confirmed at some time points. Computational analysis also revealed that different transcription factors were up-regulated in olive aerial tissues (i.e. jerf, bHLH, WRKYs, as previously reported for roots. Results confirmed that root colonization by this endophytic bacterium does not only trigger defense responses in this organ but also mount a wide array of systemic defense responses in distant tissues (stems, leaves. This sheds light on how olive plants respond to the ‘non-hostile’ colonization by a bacterial endophyte and how induced defense response can contribute to the biocontrol activity of strain PICF7.

  19. Biocontrol of Aspergillus species on peanut kernels by antifungal diketopiperazine producing Bacillus cereus associated with entomopathogenic nematode.

    Science.gov (United States)

    Kumar, Sasidharan Nishanth; Sreekala, Sreerag Ravikumar; Chandrasekaran, Dileep; Nambisan, Bala; Anto, Ruby John

    2014-01-01

    The rhabditid entomopathogenic nematode associated Bacillus cereus and the antifungal compounds produced by this bacterium were evaluated for their activity in reducing postharvest decay of peanut kernels caused by Aspergillus species in in vitro and in vivo tests. The results showed that B. cereus had a significant effect on biocontrol effectiveness in in vitro and in vivo conditions. The antifungal compounds produced by the B. cereus were purified using silica gel column chromatography and their structure was elucidated using extensive spectral analyses. The compounds were identified as diketopiperazines (DKPs) [cyclo-(L-Pro-Gly), cyclo(L-Tyr-L-Tyr), cyclo-(L-Phe-Gly) and cyclo(4-hydroxy-L-Pro-L-Trp)]. The antifungal activities of diketopiperazines were studied against five Aspergillus species and best MIC of 2 µg/ml was recorded against A. flavus by cyclo(4-hydroxy-L-Pro-L-Trp). To investigate the potential application of cyclo(4-hydroxy-L-Pro-L-Trp) to eliminate fungal spoilage in food and feed, peanut kernels was used as a food model system. White mycelia and dark/pale green spores of Aspergillus species were observed in the control peanut kernels after 2 days incubation. However the fungal growth was not observed in peanut kernels treated with cyclo(4-hydroxy-L-Pro-L-Trp). The cyclo(4-hydroxy-L-Pro-L-Trp) was nontoxic to two normal cell lines [fore skin (FS) normal fibroblast and African green monkey kidney (VERO)] up to 200 µg/ml in MTT assay. Thus the cyclo(4-hydroxy-L-Pro-L-Trp) identified in this study may be a promising alternative to chemical preservatives as a potential biopreservative agent which prevent fungal growth in food and feed. To the best of our knowledge, this is the first report demonstrating that the entomopathogenic nematode associated B. cereus and cyclo(4-hydroxy-L-Pro-L-Trp) could be used as a biocontrol agents against postharvest fungal disease caused by Aspergillus species.

  20. Effect of pyrimethanil on Cryptococcus laurentii, Rhodosporidium paludigenum, and Rhodotorula glutinis biocontrol of Penicillium expansum infection in pear fruit.

    Science.gov (United States)

    Yu, Chen; Zhou, Tao; Sheng, Kuang; Zeng, Lizhen; Ye, Changzhou; Yu, Ting; Zheng, Xiaodong

    2013-06-17

    The effect of biocontrol yeasts and pyrimethanil at low concentration on inhibition of blue mold rot caused by Penicillium expansum in pear fruit was investigated. Pyrimethanil at low concentration (40μg/mL) alone had little inhibitory activity against the P. expansum infection in pear fruit wounds although it was effective in inhibiting the survival of P. expansum on Asp-agar medium. Pyrimethanil at this low concentration significantly enhanced the efficacy of Cryptococcus laurentii at 1×10(7)CFU/mL in reducing blue mold rot in vivo compared with C. laurentii at 1×10(7)CFU/mL alone. However, there was no additive inhibitory activity when pyrimethanil was combined for application with biocontrol yeasts Rhodosporidium paludigenum or Rhodotorula glutinis. Combination of pyrimethanil and C. laurentii at low concentration also inhibited blue mold rot when P. expansum was inoculated into fruit wounds 12h before treatment and fruit was stored at low temperature (4°C). Pyrimethanil at 0.04 to 400μg/mL did not influence the survival of C. laurentii in vitro, and it only slightly reduced the population growth of C. laurentii after 48h of incubation in the pear fruit wounds. There was no significant difference in quality parameters including total soluble solids, titratable acidity and ascorbic acid of pear fruit wounds among all treatments after 5days of treatment at 25°C. Integration of C. laurentii and pyrimethanil at low concentration might be an effective and safe strategy to control P. expansum infection in pear fruit, especially in an integrated postharvest disease management strategy.

  1. Selection, Identification and Optimization of the Growth Water Probiotic Consortium of Mangrove Ecosystems as Bioremediation and Biocontrol in Shrimp Ponds

    Directory of Open Access Journals (Sweden)

    Wilis Ari Setyati

    2015-01-01

    Full Text Available Shrimp aquaculture is an activity that potentially generates organic waste. The accumulation of organic matter is becoming one of the main factors causing the emergence of disease. Problem-solving approach that is most effective is through bioremediation. The aims of this study were to select, identify and cultivate bacteria from mangrove sediments from Cilacap, Rembang and Banyuwangi which potentially as probiotic consortium of bioremediation activity and biocontrol. The results showed that total of 45 isolates (proteolytic, 35 isolates (amylolytic, 35 isolates (lipolytic, and 18 isolates (cellulolytic. There were 59 bacterial isolates had antibacterial activity of vibrio (V. harveyi, V. alginolyticus, V. vulnificus and V. anguilarum. Based on the identification of 16 S-rRNA genes, 4 isolates showed that the C2 isolate was identified as Bacillus subtilis, C11 isolate was identified as Bacillus firmus, C13 and C14 isolates were identified as B. Flexus. This study concluded that cultivation of Bacillus subtilis C2 optimum at 2% molase and yeast extract 0.5% at pH 8 and 30 0C. Bacillus firmus C11 optimum at 2% molase and yeast extract 0.5% at pH 8 and 30 0C. Bacillus flexus C13 optimum at 2% glucose and yeast extract 0.5% at pH 8 and 30 0C. Bacillus flexus C14 optimum at 4% molase and yeast extract 0.25% at pH 8 and 30 0C. The result of culture applications of 4 isolates showed an effect of increasing shrimp weight by 141, 9% compared by the control.Keywords: sediment, mangrove, bioremediation, biocontrol

  2. Complete genome sequence of Pseudomonas fluorescens strain PICF7, an indigenous root endophyte from olive (Olea europaea L.) and effective biocontrol agent against Verticillium dahliae.

    Science.gov (United States)

    Martínez-García, Pedro Manuel; Ruano-Rosa, David; Schilirò, Elisabetta; Prieto, Pilar; Ramos, Cayo; Rodríguez-Palenzuela, Pablo; Mercado-Blanco, Jesús

    2015-01-01

    Pseudomonas fluorescens strain PICF7 is a native endophyte of olive roots. Previous studies have shown this motile, Gram-negative, non-sporulating bacterium is an effective biocontrol agent against the soil-borne fungus Verticillium dahliae, the causal agent of one of the most devastating diseases for olive (Olea europaea L.) cultivation. Here, we announce and describe the complete genome sequence of Pseudomonas fluorescens strain PICF7 consisting of a circular chromosome of 6,136,735 bp that encodes 5,567 protein-coding genes and 88 RNA-only encoding genes. Genome analysis revealed genes predicting factors such as secretion systems, siderophores, detoxifying compounds or volatile components. Further analysis of the genome sequence of PICF7 will help in gaining insights into biocontrol and endophytism.

  3. Short communication. A review on the efficacy tests and risk analyses conducted on Chondrostereum purpureum, a potential biocontrol agent, in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Hantula, J.; Hamberg, L.; Vartiamaki, H.; Korhonen, K.; Uotila, A.

    2012-11-01

    Hardwood sprouting is a problem in forest regeneration areas, under electric lines, on roadsides and railways. In Finland, isolates of Chondrostereum purpureum were screened by field experiments for their efficiency to control sprouting. The proportion of dead stumps with the best isolates exceeded 80% on birch (Betula pendula and B. pubescens), and C. purpureum was also found to affect the sprouting of aspen (Populus tremula) and rowan (Sorbus aucuparia). The risks of C. purpureum based biocontrol were evaluated by population genetic analysis. It showed that C. purpureum is a geographically undifferentiated species that does not reproduce clonally. The risk of infection of non-target trees was found to be highest in early spring. These findings suggest that the risks of using C. purpureum in biocontrol are small. (Author) 36 refs.

  4. Field Studies on the Relationship between Fusarium verticillioides and Maize (Zea mays L.: Effect of Biocontrol Agents on Fungal Infection and Toxin Content of Grains at Harvest

    Directory of Open Access Journals (Sweden)

    Paola Pereira

    2011-01-01

    Full Text Available Maize (Zea mays L. is a staple food for the majority of the world's population. Fusarium verticillioides (Sacc. Nirenberg (Teleomorph: Gibberella moniliformis Wineland; synonym: F. moniliformis is both a saprophyte and a parasite of maize and can also be found as an endophyte. The presence of this fungus in maize constitutes an imminent risk due to its ability to produce fumonisins, mycotoxins with proven carcinogenic effects. The present work investigated biocontrol activity of Bacillus amyloliquefaciens and Microbacterium oleovorans against F. verticillioides infection and fumonisin B1 production in field-grown maize during four consecutive growing seasons. Treatment with B. amyloliquefaciens consistently reduced F. verticillioides inoculum and fumonisin content of harvested grains. F. verticillioides count and fumonisin levels correlated negatively with rainfall regimes; however, none of these parameters showed significant correlation with yields. Treatment with these biocontrol agents may improve phytosanitary quality of the grains and reduce toxicological risk in the maize agroecosystem.

  5. The ABC transporter ABCG29 is involved in H2O2 tolerance and biocontrol traits in the fungus Clonostachys rosea.

    Science.gov (United States)

    Dubey, Mukesh; Jensen, Dan Funck; Karlsson, Magnus

    2016-04-01

    For successful biocontrol interactions, biological control organisms must tolerate toxic metabolites produced by themselves or plant pathogens during mycoparasitic/antagonistic interactions, by host plant during colonization of the plant, and xenobiotics present in the environment. ATP-binding cassette (ABC) transporters can play a significant role in tolerance of toxic compounds by mediating active transport across the cellular membrane. This paper reports on functional characterization of an ABC transporter ABCG29 in the biocontrol fungus Clonostachys rosea strain IK726. Gene expression analysis showed induced expression of abcG29 during exposure to the Fusarium spp. mycotoxin zearalenone (ZEA) and the fungicides Cantus, Chipco Green and Apron. Expression of abcG29 in C. rosea was significantly higher during C. rosea-C. rosea (Cr-Cr) interaction or in exposure to C. rosea culture filtrate for 2 h, compared to interaction with Fusarium graminearum or 2 h exposure to F. graminearum culture filtrate. In contrast with gene expression data, ΔabcG29 strains did not display reduced tolerance towards ZEA, fungicides or chemical agents known for inducing oxidative, cell wall or osmotic stress, compared to C. rosea WT. The exception was a significant reduction in tolerance to H2O2 (10 mM) in ΔabcG29 strains when conidia were used as an inoculum. The antagonistic ability of ΔabcG29 strains towards F. graminearum, Fusarium oxysporum or Botrytis cinerea in dual plate assays were not different compared with WT. However, in biocontrol assays ΔabcG29 strains displayed reduced ability to protect Arabidopsis thaliana leaves from B. cinerea, and barley seedling from F. graminearum as measured by an A. thaliana detached leaf assay and a barley foot rot disease assay, respectively. These data show that the ABCG29 is dispensable for ZEA and fungicides tolerance, and antagonism but not H2O2 tolerance and biocontrol effects in C. rosea.

  6. Complete genome sequence of Pseudomonas fluorescens strain PICF7, an indigenous root endophyte from olive (Olea europaea L.) and effective biocontrol agent against Verticillium dahliae

    OpenAIRE

    2015-01-01

    Pseudomonas fluorescens strain PICF7 is a native endophyte of olive roots. Previous studies have shown this motile, Gram-negative, non-sporulating bacterium is an effective biocontrol agent against the soil-borne fungus Verticillium dahliae, the causal agent of one of the most devastating diseases for olive (Olea europaea L.) cultivation. Here, we announce and describe the complete genome sequence of Pseudomonas fluorescens strain PICF7 consisting of a circular chromosome of 6,136,735 bp that...

  7. 大豆胞囊线虫病生物防治研究进展%Riview of the Biocontrol on Soybean Cyst Nematode (Heterodera glycines)

    Institute of Scientific and Technical Information of China (English)

    陈立杰; 王媛媛; 朱晓峰; 段玉玺

    2011-01-01

    The biological control is an effective method to control soybean cyst nematode (Heterodera giycines). Through the in- depth researches on different methods of biological control of H.glycines, the biocontrol will be helpful on soybean production. Therefore, the biocontrol methods will play an important role in suppressing occurrence and damage of the nematodes. The article summarized the advances in the biocontrol of soybean cyst nematode, which has been done by the nematologists of Shenyang Agricultural University and some other domestic and foreign scientists in recent years. The problems and prospects on biological control of soybean cyst nematode were discussed, and the advantages and disadvantages of the biocontrol measures were mentioned. To develop new methods for soybean cyst nematode disease on biological control, the new effective methods will be researched in the future.%大豆胞囊线虫病的生物防治是有效控制大豆胞囊线虫群体的重要措施.通过对各种生物防治方法的逐渐深入研究,生物防治这一措施将在大豆生产上有效控制大豆胞囊线虫的发生与为害发挥重要作用.对近年来沈阳农业大学植物线虫研究室及部分国内外的线虫研究室在大豆胞囊线虫病生物防治方面的研究进展进行了综述,研讨过去生防措施的利弊,探索大豆胞囊线虫病生物防治的新方法,为有效控制大豆胞囊线虫病开辟新的途径.

  8. Pea Broth Enhances the Biocontrol Efficacy of Lysobacter capsici AZ78 by Triggering Cell Motility Associated with Biogenesis of Type IV Pilus.

    Science.gov (United States)

    Tomada, Selena; Puopolo, Gerardo; Perazzolli, Michele; Musetti, Rita; Loi, Nazia; Pertot, Ilaria

    2016-01-01

    Bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type IV pili. To date, little information on the mechanisms involved in the motility of the Lysobacter species has been available. Recently, L. capsici AZ78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. Pea broth medium improved also the biocontrol activity of L. capsici AZ78 against Plasmopara viticola under greenhouse conditions. Noteworthy, the quantity of pea residues remaining on grapevine leaves fostered cell motility in L. capsici AZ78. Based on these results, this unusual motility related to the composition of the growth medium was investigated in bacterial strains belonging to several Lysobacter species. The six L. capsici strains tested developed dendrite-like colonies when grown on jellified pea broth, while the development of dendrite-like colonies was not recorded in the media commonly used in motility assays. To determine the presence of genes responsible for biogenesis of the flagellum and type IV pili, the genome of L. capsici AZ78 was mined. Genes encoding structural components and regulatory factors of type IV pili were upregulated in L. capsici AZ78 cells grown on the above-mentioned medium, as compared with the other tested media. These results provide new insight into the motility mechanism of L. capsici members and the role of type IV pili and pea compounds on the epiphytic fitness and biocontrol features of L. capsici AZ78.

  9. Bacillus amyloliquefaciens subsp. plantarum GR53, a potent biocontrol agent resists Rhizoctonia disease on Chinese cabbage through hormonal and antioxidants regulation.

    Science.gov (United States)

    Kang, Sang-Mo; Radhakrishnan, Ramalingam; Lee, In-Jung

    2015-10-01

    The fungus Rhizoctonia solani is one of the causal agents of numerous diseases that affect crop growth and yield. The aim of this present investigation was to identify a biocontrol agent that acts against R. solani and to determine the agent's protective effect through phytohormones and antioxidant regulation in experimentally infected Chinese cabbage plants. Four rhizospheric soil bacterial isolates GR53, GR169, GR786, and GR320 were tested for their antagonistic activity against R. solani. Among these isolates, GR53 significantly suppressed fungal growth. GR53 was identified as Bacillus amyloliquefaciens subsp. plantarum by phylogenetic analysis of the 16S rDNA sequence. The biocontrol activity of B. amyloliquefaciens subsp. plantarum GR53 was tested in Chinese cabbage plants under controlled conditions. Results showed that R. solani inhibited plant growth (length, width, fresh and dry weight of leaves) by reducing chlorophyll and total phenolic content, as well as by increasing the levels of salicylic acid, jasmonic acid, abscisic acid, and DPPH scavenging activity. By regulating the levels of these compounds, the co-inoculation of B. amyloliquefaciens subsp. plantarum GR53 heightened induced systemic resistance in infected Chinese cabbage, effectively mitigating R. solani-induced damaging effects and improving plant growth. The results obtained from this study suggest that B. amyloliquefaciens subsp. plantarum GR53 is an effective biocontrol agent to prevent the damage caused by R. solani in Chinese cabbage plants.

  10. Endophytic colonization and biocontrol performance of Pseudomonas fluorescens PICF7 in olive (Olea europaea L.) are determined neither by pyoverdine production nor swimming motility.

    Science.gov (United States)

    Maldonado-González, M Mercedes; Schilirò, Elisabetta; Prieto, Pilar; Mercado-Blanco, Jesús

    2015-09-01

    Pseudomonas fluorescens PICF7 is an indigenous inhabitant of olive (Olea europaea L.) rhizosphere, able to display endophytic lifestyle in roots, to induce a wide range of defence responses upon colonization of this organ and to exert effective biological control against Verticillium wilt of olive (VWO) (Verticillium dahliae). We aimed to evaluate the involvement of specific PICF7 phenotypes in olive root colonization and VWO biocontrol effectiveness by generating mutants impaired in swimming motility (fliI) or siderophore pyoverdine production (pvdI). Besides, the performance of mutants with diminished in vitro growth in potato dextrose agar medium (gltA) and cysteine (Cys) auxotrophy was also assessed. Results showed that olive root colonization and VWO biocontrol ability of the fliI, pvdI and gltA mutants did not significantly differ from that displayed by the parental strain PICF7. Consequently, altered in vitro growth, swimming motility and pyoverdine production contribute neither to PICF7 VWO suppressive effect nor to its colonization ability. In contrast, the Cys auxotroph mutant showed reduced olive root colonization capacity and lost full biocontrol efficacy. Moreover, confocal laser scanning microscopy revealed that all mutants tested were able to endophytically colonize root tissue to the same extent as wild-type PICF7, discarding these traits as relevant for its endophytic lifestyle.

  11. In Planta Biocontrol of Pectobacterium atrosepticum by Rhodococcus erythropolis Involves Silencing of Pathogen Communication by the Rhodococcal Gamma-Lactone Catabolic Pathway.

    Science.gov (United States)

    Barbey, Corinne; Crépin, Alexandre; Bergeau, Dorian; Ouchiha, Asma; Mijouin, Lily; Taupin, Laure; Orange, Nicole; Feuilloley, Marc; Dufour, Alain; Burini, Jean-François; Latour, Xavier

    2013-01-01

    The virulence of numerous Gram-negative bacteria is under the control of a quorum sensing process based on synthesis and perception of N-acyl homoserine lactones. Rhodococcus erythropolis, a Gram-positive bacterium, has recently been proposed as a biocontrol agent for plant protection against soft-rot bacteria, including Pectobacterium. Here, we show that the γ-lactone catabolic pathway of R. erythropolis disrupts Pectobacterium communication and prevents plant soft-rot. We report the first characterization and demonstration of N-acyl homoserine lactone quenching in planta. In particular, we describe the transcription of the R. erythropolis lactonase gene, encoding the key enzyme of this pathway, and the subsequent lactone breakdown. The role of this catabolic pathway in biocontrol activity was confirmed by deletion of the lactonase gene from R. erythropolis and also its heterologous expression in Escherichia coli. The γ-lactone catabolic pathway is induced by pathogen communication rather than by pathogen invasion. This is thus a novel and unusual biocontrol pathway, differing from those previously described as protecting plants from phytopathogens. These findings also suggest the existence of an additional pathway contributing to plant protection.

  12. In Planta Biocontrol of Pectobacterium atrosepticum by Rhodococcus erythropolis Involves Silencing of Pathogen Communication by the Rhodococcal Gamma-Lactone Catabolic Pathway.

    Directory of Open Access Journals (Sweden)

    Corinne Barbey

    Full Text Available The virulence of numerous Gram-negative bacteria is under the control of a quorum sensing process based on synthesis and perception of N-acyl homoserine lactones. Rhodococcus erythropolis, a Gram-positive bacterium, has recently been proposed as a biocontrol agent for plant protection against soft-rot bacteria, including Pectobacterium. Here, we show that the γ-lactone catabolic pathway of R. erythropolis disrupts Pectobacterium communication and prevents plant soft-rot. We report the first characterization and demonstration of N-acyl homoserine lactone quenching in planta. In particular, we describe the transcription of the R. erythropolis lactonase gene, encoding the key enzyme of this pathway, and the subsequent lactone breakdown. The role of this catabolic pathway in biocontrol activity was confirmed by deletion of the lactonase gene from R. erythropolis and also its heterologous expression in Escherichia coli. The γ-lactone catabolic pathway is induced by pathogen communication rather than by pathogen invasion. This is thus a novel and unusual biocontrol pathway, differing from those previously described as protecting plants from phytopathogens. These findings also suggest the existence of an additional pathway contributing to plant protection.

  13. Biocontrol ability and action mechanism of food-isolated yeast strains against Botrytis cinerea causing post-harvest bunch rot of table grape.

    Science.gov (United States)

    Parafati, Lucia; Vitale, Alessandro; Restuccia, Cristina; Cirvilleri, Gabriella

    2015-05-01

    Strains belonging to the species Saccharomyces cerevisiae, Wickerhamomyces anomalus, Metschnikowia pulcherrima and Aureobasidium pullulans, isolated from different food sources, were tested in vitro as biocontrol agents (BCAs) against the post-harvest pathogenic mold Botrytis cinerea. All yeast strains demonstrated antifungal activity at different levels depending on species and medium. Killer strains of W. anomalus and S. cerevisiae showed the highest biocontrol in vitro activity, as demonstrated by largest inhibition halos. The competition for iron and the ability to form biofilm and to colonize fruit wounds were hypothesized as the main action mechanisms for M. pulcherrima. The production of hydrolytic enzymes and the ability to colonize the wounds were the most important mechanisms for biocontrol activity in A. pullulans and W. anomalus, which also showed high ability to form biofilm. The production of volatile organic compounds (VOCs) with in vitro and in vivo inhibitory effect on pathogen growth was observed for the species W. anomalus, S. cerevisiae and M. pulcherrima. Our study clearly indicates that multiple modes of action may explain as M. pulcherrima provide excellent control of postharvest botrytis bunch rot of grape.

  14. Saprotrophic competitiveness and biocontrol fitness of a genetically modified strain of the plant-growth-promoting fungus Trichoderma hamatum GD12.

    Science.gov (United States)

    Ryder, Lauren S; Harris, Beverley D; Soanes, Darren M; Kershaw, Michael J; Talbot, Nicholas J; Thornton, Christopher R

    2012-01-01

    Trichoderma species are ubiquitous soil fungi that hold enormous potential for the development of credible alternatives to agrochemicals and synthetic fertilizers in sustainable crop production. In this paper, we show that substantial improvements in plant productivity can be met by genetic modification of a plant-growth-promoting and biocontrol strain of Trichoderma hamatum, but that these improvements are obtained in the absence of disease pressure only. Using a quantitative monoclonal antibody-based ELISA, we show that an N-acetyl-β-d-glucosaminidase-deficient mutant of T. hamatum, generated by insertional mutagenesis of the corresponding gene, has impaired saprotrophic competitiveness during antagonistic interactions with Rhizoctonia solani in soil. Furthermore, its fitness as a biocontrol agent of the pre-emergence damping-off pathogen Sclerotinia sclerotiorum is significantly reduced, and its ability to promote plant growth is constrained by the presence of both pathogens. This work shows that while gains in T. hamatum-mediated plant-growth-promotion can be met through genetic manipulation of a single beneficial trait, such a modification has negative impacts on other aspects of its biology and ecology that contribute to its success as a saprotrophic competitor and antagonist of soil-borne pathogens. The work has important implications for fungal morphogenesis, demonstrating a clear link between hyphal architecture and secretory potential. Furthermore, it highlights the need for a holistic approach to the development of genetically modified Trichoderma strains for use as crop stimulants and biocontrol agents in plant agriculture.

  15. Pea broth enhances the biocontrol efficacy of Lysobacter capsici AZ78 by triggering cell motility associated with biogenesis of type IV pilus

    Directory of Open Access Journals (Sweden)

    Selena Tomada

    2016-07-01

    Full Text Available Bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type IV pili. To date, little information on the mechanisms involved in the motility of the Lysobacter species has been available. Recently, L. capsici AZ78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. Pea broth medium improved also the biocontrol activity of L. capsici AZ78 against Plasmopara viticola under greenhouse conditions. Noteworthy, the quantity of pea residues remaining on grapevine leaves fostered cell motility in L. capsici AZ78. Based on these results, this unusual motility related to the composition of the growth medium was investigated in bacterial strains belonging to several Lysobacter species. The six L. capsici strains tested developed dendrite-like colonies when grown on jellified pea broth, while the development of dendrite-like colonies was not recorded in the media commonly used in motility assays. To determine the presence of genes responsible for biogenesis of the flagellum and type IV pili, the genome of L. capsici AZ78 was mined. Genes encoding structural components an d regulatory factors of type IV pili were upregulated in L. capsici AZ78 cells grown on the above-mentioned medium, as compared with the other tested media. These results provide new insight into the motility mechanism of L. capsici members and the role of type IV pili and pea compounds on the epiphytic fitness and biocontrol features of L. capsici AZ78.

  16. Survival of the biocontrol agents Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116 on the spikes of barley in the field

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin; ZHANG Bing-xin; ZHANG Zhen; SHEN Wei-feng; YANG Ching-hong; YU Jing-quan; ZHAO Yu-hua

    2005-01-01

    Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating disease that results in extensive yield losses to wheat and barley. A green fluorescent protein (GFP) expressing plasmid pRP22-GFP was constructed for monitoring the colonization of two biocontrol agents, Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116, on the spikes of barley and their effect on suppression of FHB. Survival and colonization of the Brevibacillus brevis ZJY- 1 and Bacillus subtilis ZJY- 116 strains on spikes of barley were observed by tracking the bacterial transformants with GFP expression. Our field study revealed that plasmid pRP22-GFP was stably maintained in the bacterial strains without selective pressure. The retrieved GFP-tagged strains showed that the bacterial population fluctuation accorded with that of the rain events. Furthermore, both biocontrol strains gave significant protection against FHB on spikes of barley in fields. The greater suppression of barley FHB disease was resulted from the treatment of barley spikes with biocontrol agents before inoculation with F. graminearum.

  17. Improvement of Biocontrol of Damping-off and Root Rot/Wilt of Faba Bean by Salicylic Acid and Hydrogen Peroxide.

    Science.gov (United States)

    Abdel-Monaim, Montaser Fawzy

    2013-03-01

    Rhizoctonia solani, Fusarium solani, F. oxysporum, and Macrophomina phaseolina were found to be associated with root rott and wilt symptoms of faba bean plants collected from different fieldes in New Valley governorate, Egypt. All the obtained isolates were able to attack faba bean plants (cv. Giza 40) causing damping-off and root rot/wilt diseases. R. solani isolates 2 and 5, F. solani isolate 8, F. oxysporum isolate 12 and M. phaseolina isolate 14 were the more virulent ones in the pathogenicity tests. Biocontrol agents (Trichoderma viride and Bacillus megaterium) and chemical inducers (salicylic acid [SA] and hydrogen peroxide) individually or in combination were examined for biological control of damping-off and root rot/wilt and growth promoting of faba bean plants in vitro and in vivo. Both antagonistic biocontrol agents and chemical inducers either individually or in combination inhibited growth of the tested pathogenic fungi. Biocontrol agents combined with chemical inducers recorded the highest inhibited growth especially in case SA + T. viride and SA + B. megaterium. Under green house and field conditions, all treatments significantly reduced damping-off and root rot/wilt severity and increased of survival plants. Also, these treatments increased fresh and weights of the survival plants in pots compared with control. The combination between biocontrol agents and chemical inducers were more effective than used of them individually and SA + T. viride was the best treatment in this respect. Also, under field conditions, all these treatments significantly increased growth parameters (plant height and number of branches per plant) and yield components (number of pods per plant and number of seeds per plant, weight of 100 seeds and total yield per feddan) and protein content in both seasons (2010~2011 and 2011~2012). Faba bean seeds soaked in SA + T. viride and SA + B. megaterium were recorded the highest growth parameters and yield components. Generally, the

  18. A river system to watch: documenting the effects of saltcedar (Tamarix spp.) biocontrol in the Virgin River valley

    Science.gov (United States)

    Bateman, Heather L.; Dudley, Tom L.; Bean, Dan W.; Ostoja, Steven M.; Hultine, Kevin R.; Kuehn, Michael J.

    2010-01-01

    Throughout riparian areas of the southwestern United States, non-native saltcedar (also known as tamarisk; Tamarix spp.) can form dense, monotypic stands and is often reported to have detrimental effects on native plants and habitat quality (Everitt 1980; Shafroth et al. 2005). Natural resource managers of these riparian areas spend considerable time and resources controlling saltcedar using a variety of techniques, including chemical (Duncan and McDaniel 1998), mechanical, and burning methods (Shafroth et al. 2005). Approximately one billion dollars are spent each year on river restoration projects nationally (Bernhardt et al. 2005), and a majority of these projects focus on invasive species control in the Southwest (Follstad Shah et al. 2007). A technique that has drawn much attention is the use of the saltcedar leaf beetle (Diorhabda spp.), a specialist herbivore, as biological control of saltcedar (Lewis et al. 2003). Research testing was conducted with beetles housed in secure enclosures in six states in 1998 and 1999 (Dudley et al. 2001), followed by open release at some of those sites starting in 2001 (DeLoach et al. 2004). By 2005, full-scale saltcedar biocontrol was implemented in 13 states, led by the USDA Animal and Plant Health Inspection Service (APHIS), the agency that oversees biological control programs, and with the participation and support of the U.S. Fish and Wildlife Service (USFWS). Despite the widespread application of Diorhabda, however, only limited research has quantified the consequences (benefits and costs) on biotic communities and ecosystem services. Alterations to riparian areas caused by various non-native species control activities have the potential to affect a variety of habitat types used by wildlife (Bateman et al. 2008a); processes like water availability, fluvial deposition, and erosion; and the establishment of other non-native species (Carruthers and D'Antonio 2005, Shafroth et al. 2005, DeLoach et al. 2006). Similarly

  19. Biocontrol of Aspergillus species on peanut kernels by antifungal diketopiperazine producing Bacillus cereus associated with entomopathogenic nematode.

    Directory of Open Access Journals (Sweden)

    Sasidharan Nishanth Kumar

    Full Text Available The rhabditid entomopathogenic nematode associated Bacillus cereus and the antifungal compounds produced by this bacterium were evaluated for their activity in reducing postharvest decay of peanut kernels caused by Aspergillus species in in vitro and in vivo tests. The results showed that B. cereus had a significant effect on biocontrol effectiveness in in vitro and in vivo conditions. The antifungal compounds produced by the B. cereus were purified using silica gel column chromatography and their structure was elucidated using extensive spectral analyses. The compounds were identified as diketopiperazines (DKPs [cyclo-(L-Pro-Gly, cyclo(L-Tyr-L-Tyr, cyclo-(L-Phe-Gly and cyclo(4-hydroxy-L-Pro-L-Trp]. The antifungal activities of diketopiperazines were studied against five Aspergillus species and best MIC of 2 µg/ml was recorded against A. flavus by cyclo(4-hydroxy-L-Pro-L-Trp. To investigate the potential application of cyclo(4-hydroxy-L-Pro-L-Trp to eliminate fungal spoilage in food and feed, peanut kernels was used as a food model system. White mycelia and dark/pale green spores of Aspergillus species were observed in the control peanut kernels after 2 days incubation. However the fungal growth was not observed in peanut kernels treated with cyclo(4-hydroxy-L-Pro-L-Trp. The cyclo(4-hydroxy-L-Pro-L-Trp was nontoxic to two normal cell lines [fore skin (FS normal fibroblast and African green monkey kidney (VERO] up to 200 µg/ml in MTT assay. Thus the cyclo(4-hydroxy-L-Pro-L-Trp identified in this study may be a promising alternative to chemical preservatives as a potential biopreservative agent which prevent fungal growth in food and feed. To the best of our knowledge, this is the first report demonstrating that the entomopathogenic nematode associated B. cereus and cyclo(4-hydroxy-L-Pro-L-Trp could be used as a biocontrol agents against postharvest fungal disease caused by Aspergillus species.

  20. Study on antifungal activities of biocontrol yeasts against Botrytis cinerea%三株生防酵母菌对Botrytis cinerea的抑菌作用研究

    Institute of Scientific and Technical Information of China (English)

    王傲雪; 关鑫; 张俊峰; 张珍珠; 王瑞虎; 陈秀玲

    2014-01-01

    In this study, the antifungal activities of biocontrol yeasts Cryptococcus albidus 63(Ca63), Cryptococcus albidus 64 (Ca64) and Candida parapsilosis yett1006 against Botrytis cinerea were investigated. The dual culture between three biocontrol yeasts and B. cinerea t08016b results showed that no obvious inhibiting zone appeared, but the pathogen growed more weakly than the control. The results of chitinase andβ-1, 3-glucanase activities assay showed that the levels of the two enzymes activities did not change significantly (P>0.05) when the three biocontrol yeasts cultured with pathogen. The inhibition rates of three biocontrol yeast strains on mycelium growth were 88.57%, 90.66% and 85.65%, respectively. High concentrations of biocontrol yeasts had a strong inhibitory effect on the spore germination of B. cinerea t08016b. Especial y, 1 × 108 cfu·mL-1 biocontrol yeasts almost stopped the spore germination of B. cinerea t08016b. Heat-inactived yeast suspension and culture supernatant had no significant inhibitory effects on B. cinerea. These results il ustrated that the antagonic effect of biocontrol yeasts was mainly due to the competition of limited space and nutrient conditions, not secreting antifungal substances.%针对三株生防酵母菌Cryptococcus albidus 63(Ca63)、Cryptococcus albidus 64(Ca64)、Candida parapsilosis yett1006对番茄灰霉病病原菌B. cinerea t08016b的抑菌作用进行研究。三株生防酵母菌与B. cinerea t08016b的对峙培养过程中,未产生明显抑菌圈,均可减弱B. cinerea t08016b生长势;几丁质酶和β-1,3-葡聚糖酶活性测定结果表明, t08016b并无诱导三株酵母菌分泌酶活显著增加(P>0.05);研究酵母菌对B. cinerea t08016b菌丝生长和孢子萌发率影响发现,C.albidus 63、C.albidus 64和C.parapsilosis yett1006对菌丝生长量的抑制率分别为88.57%、90.66%和85.65%,高浓度菌液对孢子萌发有显著抑制效果,1×108 cfu·mL-1菌体活

  1. Isolation and Selection of Epiphytic Yeast for Biocontrol of Botrytis cinerea Pers. on Table Grapes Aislación y Selección de Levaduras Epífitas para el Biocontrol de Botrytis cinerea Pers. en Uva de Mesa

    Directory of Open Access Journals (Sweden)

    Marisol Vargas

    2012-09-01

    Full Text Available Botrytis cinerea Pers., the causal agent of gray mold, infects more than 200 plant species. This pathogen has traditionally been controlled by fungicides. However, with the increasing demand for pesticide-free foods new control strategies are needed. The objective of this study was to isolate and select grapevine (Vitis vinifera L. epiphytic yeasts for the biocontrol of B. cinerea in table grapes. Of the total isolated yeasts (n = 256, 32 exhibited mycelial growth inhibition in dual cultures with a halo > 4 mm, and eight of these isolates inhibited > 90% of conidial germination. When evaluating increasing concentrations on conidial germination inhibition, a dose-dependent response was observed with EC90 values from 0.45 x 10(5 to 0.22 x 10(8 cells mL-1. The antagonistic activity of six yeasts against B. cinerea in table grape berries 'Flame Seedless' increased as the yeast colonization time increased from 1 to 24 h on the berries, resulting in a higher biocontrol activity on B. cinerea. These results show the effectiveness of grapevine epiphytic yeasts as biocontrol agents of B. cinerea on table grapes.Botrytis cinerea Pers., agente causal de la pudrición gris, infecta a más de 200 especies vegetales. Tradicionalmente, este patógeno ha sido controlado con fungicidas; sin embargo, la creciente demanda de alimentos libres de pesticidas hace necesario el uso de nuevas estrategias de control. El objetivo de este estudio fue aislar y seleccionar levaduras epífitas de vid (Vitis vinifera L. para el biocontrol de B. cinerea en uva de mesa. Del total de levaduras aisladas (n = 256, 32 presentaron inhibición del crecimiento micelial, en cultivos duales, con un halo > 4 mm y ocho de estos aislamientos inhibieron la germinación de conidias > 90%. Al evaluar concentraciones crecientes de levaduras sobre la inhibición de la germinación de conidias, se observó una respuesta dosis-dependiente, con valores de CE90 de 0,45 x 10(5 a 0,22 x 10(8 c

  2. Improving biocontrol activity of Pseudomonas fluorescens through chromosomal integration of 2,4-diacetylphloro- glucinol biosynthesis genes

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hongyou; WEI Hailei; LIU Xili; WANG Ye; ZHANG Liqun; TANG Wenhua

    2005-01-01

    Antibiotic 2,4-diacetylphloroglucinol (2,4- DAPG) produced by Pseudomonas fluorescens CPF-10 and 2P24 is a principal factor enabling bacteria to suppress plant diseases caused by soilborne pathogens. In this study, a 2,4-DAPG biosynthesis locus phlACBDE cloned from strain CPF-10 was assembled into a mini-Tn5 transposon and introduced into the chromosome of P. fluorescens P32 (2,4- DAPG-), CPF-10 and 2P24 to construct the 2,4-DAPG overproducing derivatives P32-38, CPF10-9 and 2P24-48, respectively. All the transgenic strains showed an enhanced antibiosis capacity against plant microbial pathogens in vitro and two strains, P32-38 and CPF10-9, provided significantly better protection against wheat take-all disease caused by Gaeumannomyces graminis var. tritici and tomato bacterial wilt caused by Ralstonia solanacearum in greenhouse. Compared to their parental strains, the 2,4-DAPG overproducing derivatives colonized to the same extent on the wheat tips in the autoclaved soil, but developed larger populations in natural soil. These results indicated that production of antibiotics 2,4- DAPG by biological control pseudomonads can contribute not only to their disease suppression capacities but also to the ecological competence in the resident microflora. Our research also suggests that it is a realistic approach to improve biocontrol capacity of P. fluorescens through the genetic modification of its antibiotic 2,4-DAPG production.

  3. Effects of local vegetation and plantation age for the parasitoid Asecodes mento-a biocontrol agent in organic strawberry fields

    Institute of Scientific and Technical Information of China (English)

    Johan A.Stenberg

    2012-01-01

    The parasitoid Asecodes mento (Walker,1839) (Hymenoptera:Eulophidae)is the most important biocontrol agent of the strawberry leaf beetle Galerucella tenella (L.) (Coleoptera:Chrysomelidae) in northern Europe.Here,I investigated whether natural parasitism in organic strawberry plantations was affected by the presence of the alternative host plant meadowsweet (Filipendula ulmaria),and whether parasitism rates differed between plantations of different ages (6 to 79 years).I also investigated whether parasitoid brood size,body size and sex ratio differed between the two host plants in the field.Parasitism was very low (0%) in newly established plantations and increased to a plateau (~40%) in fields where strawberries had been grown for approximately 20 years or longer.Such an extended colonization process is unacceptable for commercial growers.It would thus be desirable to find a method to catalyze parasitoid population buildup in young plantations.Parasitoid brood sizes were larger in beetles collected from meadowsweet,while body size and sex ratio did not differ between parasitoids collected from the two plants.These findings suggest that meadowsweet can export parasitoids to neighboring strawberry fields.Although this is a possibility,I did not find any significant differences in parasitism rates between isolated strawberry fields and fields adjacent to meadowsweet stands,indicating that effects of local vegetation are small on parasitism rates.Releasing parasitoids in newly established strawberry plantations may be a better strategy for quickly obtaining high parasitism than intercropping with meadowsweet.

  4. Biocontrol of Late Blight (Phytophthora capsici Disease and Growth Promotion of Pepper by Burkholderia cepacia MPC-7

    Directory of Open Access Journals (Sweden)

    Mao Sopheareth

    2013-03-01

    Full Text Available A chitinolytic bacterial strain having strong antifungal activity was isolated and identified as Burkholderia cepacia MPC-7 based on 16S rRNA gene analysis. MPC-7 solubilized insoluble phosphorous in hydroxyapatite agar media. It produced gluconic acid and 2-ketogluconic acid related to the decrease in pH of broth culture. The antagonist produced benzoic acid (BA and phenylacetic acid (PA. The authentic compounds, BA and PA, showed a broad spectrum of antimicrobial activity against yeast, several bacterial and fungal pathogens in vitro. To demonstrate the biocontrol efficiency of MPC-7 on late blight disease caused by Phytophthora capsici, pepper plants in pot trials were treated with modified medium only (M, M plus zoospore inoculation (MP, MPC-7 cultured broth (B and B plus zoospore inoculation (BP. With the sudden increase in root mortality, plants in MP wilted as early as five days after pathogen inoculation. However, plant in BP did not show any symptom of wilting until five days. Root mortality in BP was markedly reduced for as much as 50%. Plants in B had higher dry weight, P concentration in root, and larger leaf area compared to those in M and MP. These results suggested that B. cepacia MPC-7 should be considered as a candidate for the biological fertilizer as well as antimicrobial agent for pepper plants.

  5. Tomato progeny inherit resistance to the nematode Meloidogyne javanica linked to plant growth induced by the biocontrol fungus Trichoderma atroviride

    Science.gov (United States)

    Medeiros, Hugo Agripino de; Araújo Filho, Jerônimo Vieira de; Freitas, Leandro Grassi de; Castillo, Pablo; Rubio, María Belén; Hermosa, Rosa; Monte, Enrique

    2017-01-01

    Root-knot nematodes (RKN) are major crop pathogens worldwide. Trichoderma genus fungi are recognized biocontrol agents and a direct activity of Trichoderma atroviride (Ta) against the RKN Meloidogyne javanica (Mj), in terms of 42% reduction of number of galls (NG), 60% of number of egg masses and 90% of number of adult nematodes inside the roots, has been observed in tomato grown under greenhouse conditions. An in vivo split-root designed experiment served to demonstrate that Ta induces systemic resistance towards Mj, without the need for the organisms to be in direct contact, and significantly reduces NG (20%) and adult nematodes inside tomato roots (87%). The first generation (F1) of Ta-primed tomato plants inherited resistance to RKN; although, the induction of defenses occurred through different mechanisms, and in varying degrees, depending on the Ta-Mj interaction. Plant growth promotion induced by Ta was inherited without compromising the level of resistance to Mj, as the progeny of Ta-primed plants displayed increased size and resistance to Mj without fitness costs. Gene expression results from the defense inductions in the offspring of Ta-primed plants, suggested that an auxin-induced reactive oxygen species production promoted by Ta may act as a major defense strategy during plant growth. PMID:28071749

  6. Biocontrol agents-mediated suppression of oxalic acid induced cell death during Sclerotinia sclerotiorum-pea interaction.

    Science.gov (United States)

    Jain, Akansha; Singh, Akanksha; Singh, Surendra; Sarma, Birinchi Kumar; Singh, Harikesh Bahadur

    2015-05-01

    Oxalic acid (OA) is an important pathogenic factor during early Sclerotinia sclerotiorum-host interaction and might work by reducing hydrogen peroxide production (H2 O2 ). In the present investigation, oxalic acid-induced cell death in pea was studied. Pea plants treated with biocontrol agents (BCAs) viz., Pseudomonas aeruginosa PJHU15, Bacillus subtilis BHHU100, and Trichoderma harzianum TNHU27 either singly and/or in consortium acted on S. sclerotiorum indirectly by enabling plants to inhibit the OA-mediated suppression of oxidative burst via induction of H2 O2 . Our results showed that BCA treated plants upon treatment with culture filtrate of the pathogen, conferred the resistance via. significantly decreasing relative cell death of pea against S. sclerotiorum compared to control plants without BCA treatment but treated with the culture filtrate of the pathogen. The results obtained from the present study indicate that the microbes especially in consortia play significant role in protection against S. sclerotiorum by modulating oxidative burst and partially enhancing tolerance by increasing the H2 O2 generation, which is otherwise suppressed by OA produced by the pathogen.

  7. Toxicity assessment of metabolites of fungal biocontrol agents using two different (Artemia salina and Daphnia magna) invertebrate bioassays.

    Science.gov (United States)

    Favilla, M; Macchia, L; Gallo, A; Altomare, C

    2006-11-01

    Fungal biocontrol agents (BCAs) have been marketed for control of crop pests, weeds, and diseases. However, BCAs may produce toxic metabolites, whose presence in the formulated products, in the crops and in the environment should be considered along with the associated risk. Two invertebrate models, viz. Artemia salina and Daphnia magna were used to assess the acute toxicity of seven BCA metabolites, characterized by different chemical nature and mode of action, namely alamethicin (ALA), paracelsin (PCS), antiamoebin (AAM), gliotoxin (GTX), destruxin A (DA), oosporein (OOS), and elsinochrome A (EA). The two invertebrates were very sensitive to all the metabolites examined, except OOS. The LC50s after 24 and 36 h exposures showed the following toxicity ranks: A. salina, DA > ALA > EA > GTX > AAM > PCS (LC50s ranging from 9.78 to 40.84 microg/ml at 24 h and from 2.92 to 18.56 microg/ml at 36 h); D. magna, DA > GTX = EA > ALA > PCS > AAM (LC50s ranging from 0.20 to 24.41 microg/ml at 24h and from 0.16 to 11.98 microg/ml at 36 h). LC50 of OOS to D. magna increased dramatically in 36 h exposure, compared to 24 h exposures (5.84 and 68.40 microg/ml, respectively). A. salina and D. magna proved to be suitable models for rapid and inexpensive screening of toxicity of BCAs at an early stage of product development.

  8. The Sensor Kinase GacS Negatively Regulates Flagellar Formation and Motility in a Biocontrol Bacterium, Pseudomonas chlororaphis O6

    Directory of Open Access Journals (Sweden)

    Ji Soo Kim

    2014-06-01

    Full Text Available The GacS/GacA two component system regulates various traits related to the biocontrol potential of plant-associated pseudomonads. The role of the sensor kinase, GacS, differs between strains in regulation of motility. In this study, we determined how a gacS mutation changed cell morphology and motility in Pseudomonas chlororaphis O6. The gacS mutant cells were elongated in stationary-phase compared to the wild type and the complemented gacS mutant, but cells did not differ in length in logarithmic phase. The gacS mutant had a two-fold increase in the number of flagella compared with the wild type strain; flagella number was restored to that of the wild type in the complemented gacS mutant. The more highly flagellated gacS mutant cells had greater swimming motilities than that of the wild type strain. Enhanced flagella formation in the gacS mutant correlated with increased expression of three genes, fleQ, fliQ and flhF, involved in flagellar formation. Expression of these genes in the complemented gacS mutant was similar to that of the wild type. These findings show that this root-colonizing pseudomonad adjusts flagella formation and cell morphology in stationary-phase using GacS as a major regulator.

  9. Production of trichodiene by Trichoderma harzianum alters the perception of this biocontrol strain by plants and antagonized fungi.

    Science.gov (United States)

    Malmierca, Mónica G; McCormick, Susan P; Cardoza, Rosa E; Alexander, Nancy J; Monte, Enrique; Gutiérrez, Santiago

    2015-08-01

    Trichothecenes are phytotoxic sesquiterpenic mycotoxins that can act as virulence factors in plant diseases. Harzianum A (HA) is a non-phytotoxic trichothecene produced by Trichoderma arundinaceum. The first step in HA biosynthesis is the conversion of farnesyl diphosphate to trichodiene (TD), a volatile organic compound (VOC), catalysed by a sesquiterpene synthase encoded by the tri5 gene. Expression of tri5 in the biocontrol strain Trichoderma harzianum CECT 2413 resulted in production of TD in parallel with a reduction of ergosterol biosynthesis and an unexpected increase in the level of squalene. Transformants expressing tri5 displayed low chitinase activity and induced expression of Botrytis cinerea BOT genes, although their total antagonistic potential against phytopathogenic fungi was not reduced. VOCs released by the tri5-transformant induced expression of tomato defence genes related to salicylic acid (SA), and TD itself strongly induced the expression of SA-responsive genes and reduced the development of lateral roots. Together, these results suggest that TD acts as a signalling VOC in the interactions of Trichoderma with plants and other microorganisms by modulating the perception of this fungus to a given environment. Moreover, the TD ability to induce systemic defences indicates that complex trichothecene structures may not be necessary for inducing such responses.

  10. Silver nanoparticles from Prosopis glandulosa and their potential application as biocontrol of Acinetobacter calcoaceticus and Bacillus cereus

    Directory of Open Access Journals (Sweden)

    Ali Abdelmoteleb

    2017-01-01

    Full Text Available In the present study the characterization and properties of silver nanoparticles from Prosopis glandulosa leaf extract (AgNPs were investigated using UV–Vis spectroscopic techniques, energy dispersive X-ray spectrometers (EDS, zeta potential and dynamic light scattering. The UV–Vis spectroscopic analysis showed the absorbance peaked at 487 nm, which indicated the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles had Z-average diameter of 421 nm with higher stability (−200 mV. The EDS analysis also exhibited presentation of silver element. Additionally, the different concentrations of AgNPs (25, 50, 75 and 100 mg/mL showed antibacterial activity against Acinetobacter calcoaceticus and Bacillus cereus. Finally, AgNPs from leaf extracts of P. glandulosa may be used as an agent of biocontrol of microorganism of importance medical. However, further studies will be needed to fully understand the antimicrobial activity of silver nanoparticles obtain from P. glandulosa.

  11. Effect of biocontrol agents Candida sake and Pantoea agglomerans on Penicillium expansum growth and patulin accumulation in apples.

    Science.gov (United States)

    Morales, Hector; Sanchis, Vicente; Usall, Josep; Ramos, Antonio J; Marín, Sonia

    2008-02-29

    Penicillium expansum is the major responsible of fruit pome decaying in cold storage. Apples spoiled by P. expansum are expected to contain patulin, a mycotoxin which is proven to affect human health. The use of chemicals is the most common procedure to prevent rots in postharvest but legislation is becoming more and more restrictive. The use of biocontrol agents (BCA) as an alternative tool is currently being proposed. The aim of this study was to evaluate the effect of two BCA (Candida sake CPA-2 and Pantoea agglomerans CPA-1) on P. expansum growth and patulin accumulation in cold storage and further deck (ambient) storage. Wounded apples were inoculated with a cell suspension of either C. sake or P. agglomerans and with a P. expansum conidial suspension. Apples were cold stored at 1 degrees C until lesion diameter reached 2 or 4 cm. Half the apples of each treatment were further stored at 20 degrees C for three days before patulin analyses. Both BCA tested controlled blue rot and patulin accumulation during cold storage. The control of P. expansum growth was enhanced in C. sake treated apples. On the other side, control of patulin accumulation in P. agglomerans treated apples seemed to be more efficient. BCA treatment could not control blue rot and patulin accumulation during further storage at room temperature and in some cases, an increase in P. expansum aggressiveness was observed.

  12. In vitro evaluation of Pseudomonas bacterial isolates from rice phylloplane for biocontrol of Rhizoctonia solani and plant growth promoting traits.

    Science.gov (United States)

    Akter, Shamima; Kadir, Jugah; Juraimi, Abdul Shukor; Saud, Halimi Mohd

    2016-07-01

    The ability for biocontrol and plant growth promotion of three Pseudomonas bacterial isolates namely Pseudomonas fluorescens (UMB20), Pseudomonas aeruginosa (KMB25) and Pseudomonas asplenii (BMB42) obtained from rice plants was investigated. Fungal growth inhibition by the isolates ranged from 86.85 to 93.15% in volatile and 100% in diffusible metabolites test. Among the isolates, BMB42 showed fungal growth inhibition significantly in the volatile metabolite test. Isolates UMB20 and BMB42 were able to synthesis chitinase with chitinolytic indices of 13.66 and 13.50, respectively. In case of -1,3-glucanase, all the isolates showed activity to produce this enzyme at varied levels and isolate KMB25 showed significantly highest activity (53.53 ppm). Among the three isolates, KMB25 showed positive response to protease production and all of them were negative to pectinase and lipase and positive to the production of siderophore, and HCN, and were able to solubilize tricalcium phosphate. All the three bacterial isolates were capable of forming biofilm at different levels. Above results suggest that phylloplane Pseudomonas bacterial isolates have potential for antifungal activities and plant growth promotion.

  13. Screening, identification, optimization of fermentation conditions, and extraction of secondary metabolites for the biocontrol of Rhizoctonia Solani AG-3

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    Taswar Ahsan

    2017-01-01

    Full Text Available In this study a strain of Streptomyces sp. was isolated from soil and identified by 16S rRNA gene sequencing technology. The strain was screened for antibiotics production effective against biocontrol of Rhizoctonia solani AG-3 to cure the target spot disease in tobacco. For enhance production of secondary metabolites, central composite design of response surface methodology (RSM was applied in submerged fermentation. The maximum metabolite production was using medium volume of 55 mL in 250 mL flask, agitation speed of 165 rpm, incubation temperature 30 °C, initial medium pH of 6.8 and inoculum size of 7%. Solvent extraction method was used to extract the secondary metabolites and active compounds were purified by silica gel column chromatography. The purified fractions were further investigated by gas chromatography-mass spectrophotometer (GC-MS. GC-MS analysis showed 48 compounds, among them 12 were active against pathogen. These findings indicated that the strain Streptomyces TA 1123 was a potential antagonist against R. solani AG-3.

  14. [Discussion on applications and mechanisms of biocontrol microoganisms used for controlling medicinal plant soil-borne diseases].

    Science.gov (United States)

    Yang, Li; Chen, Mei-Lan; Shao, Ai-Juan; Yang, Guang

    2012-11-01

    In recent years, the soil borne disease of medicinal plants becomes severely during the process of cultivation and directly endangered the production and quality of raw materials used in traditional Chinese medicine (TCM). The chemical pesticides have been constantly used to prevent and control the soil borne disease, but only a few are effective. Meanwhile, the excessive uses of chemical pesticides also lead pesticide residues in TCM, which often exceed limit of the standard, and harm the human health and cause environmental pollution. Therefore, biological control has become a hot research point for its environmental advantages. This paper mainly discussed the mechanisms of different species of microorganisms, which could control the soil borne disease of medicinal plants, from the following aspects: improving host plants' nutrient absorption, the nutrient and space competition with the pathogenic bacteria, changing the morphology and anatomical structure of roots, adjusting the host plants' endogenous hormones, restoring the balance of host rhizosphere soil microecology and activating the host plants' defense system etc. Then put forward the prospect of biocontrol agents in the future.

  15. In Vitro Screening for Abiotic Stress Tolerance in Potent Biocontrol and Plant Growth Promoting Strains of Pseudomonas and Bacillus spp.

    Directory of Open Access Journals (Sweden)

    G. Praveen Kumar

    2014-01-01

    Full Text Available Plant growth promoting rhizobacteria (PGPR has been identified as a group of microbes that are used for plant growth enhancement and biocontrol for management of plant diseases. The inconsistency in performance of these bacteria from laboratory to field conditions is compounded due to the prevailing abiotic stresses in the field. Therefore, selection of bacterial strains with tolerance to abiotic stresses would benefit the end-user by successful establishment of the strain for showing desired effects. In this study we attempted to isolate and identify strains of Bacillus and Pseudomonas spp. with stress tolerance and proven ability to inhibit the growth of potential phytopathogenic fungi. Screening of bacterial strains for high temperature (50°C, salinity (7% NaCl, and drought (−1.2 MPa showed that stress tolerance was pronounced less in Pseudomonas isolates than in Bacillus strains. The reason behind this could be the formation of endospores by Bacillus isolates. Tolerance to drought was high in Pseudomonas strains than the other two stresses. Three strains, P8, P20 and P21 showed both salinity and temperature tolerance. P59 strain possessed promising antagonistic activity and drought tolerance. The magnitude of antagonism shown by Bacillus isolates was also higher when compared to Pseudomonas strains. To conclude, identification of microbial candidate strains with stress tolerance and other added characteristic features would help the end-user obtain the desired beneficial effects.

  16. PhoR/PhoP two component regulatory system affects biocontrol capability of Bacillus subtilis NCD-2

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    Qinggang Guo

    2010-01-01

    Full Text Available The Bacillus subtilis strain NCD-2 is an important biocontrol agent against cotton verticillium wilt and cotton sore shin in the field, which are caused by Verticillium dahliae Kleb and Rhizoctonia solani Kuhn, respectively. A mutant of strain NCD-2, designated M216, with decreased antagonism to V. dahliae and R. solani, was selected by mini-Tn10 mutagenesis and in vitro virulence screening. The inserted gene in the mutant was cloned and identified as the phoR gene, which encodes a sensor kinase in the PhoP/PhoR two-component system. Compared to the wild-type strain, the APase activities of the mutant was decreased significantly when cultured in low phosphate medium, but no obvious difference was observed when cultured in high phosphate medium. The mutant also grew more slowly on organic phosphate agar and lost its phosphatidylcholine-solubilizing ability. The suppression of cotton seedling damping-off in vivo and colonization of the rhizosphere of cotton also decreased in the mutant strain when compared with the wild type strain. All of these characteristics could be partially restored by complementation of the phoR gene in the M216 mutant.

  17. Isolation, evaluation and characterization of Bacillus subtilis from cotton rhizospheric soil with biocontrol activity against Fusarium oxysporum.

    Science.gov (United States)

    Gajbhiye, Archana; Rai, Alok R; Meshram, Sudhir U; Dongre, A B

    2010-07-01

    Present investigation is based on the isolation of Bacillus subtilis from cotton rhizosphere and their evaluation as biocontrol agent against Fusarium oxysporum. The production of extracellular hydrolytic enzyme was studied for determining the antagonism. 43% of 21 isolates were identified under the B. subtilis group on the basis of biochemical characterization. 38% isolates showed competitive activity against Fusarium oxysporum and exhibit more than 50% mycelial inhibition in dual culture bioassay. The pot assay of cotton by seed treatment and soil amendment technique under green house condition showed the competent activity of the isolates in preventing the wilting of cotton seedlings due to F. oxysporum infection. SVI values of 30 day old seedlings indicated that the soil inoculation with B. subtilis BP-2 and seed treatment with B. subtilis BP-9 significantly promoted the growth of cotton seedlings. RAPD profiling revealed the diversity in the Bacillus subtilis group, ranging from 10 to 32%. The discriminative pattern among the isolates belonging to the same species was validated by 16S rDNA partial sequencing which identified them into four different strains of B. subtilis.

  18. PhoR/PhoP two component regulatory system affects biocontrol capability of Bacillus subtilis NCD-2.

    Science.gov (United States)

    Guo, Qinggang; Li, Shezeng; Lu, Xiuyun; Li, Baoqing; Ma, Ping

    2010-04-01

    The Bacillus subtilis strain NCD-2 is an important biocontrol agent against cotton verticillium wilt and cotton sore shin in the field, which are caused by Verticillium dahliae Kleb and Rhizoctonia solani Kuhn, respectively. A mutant of strain NCD-2, designated M216, with decreased antagonism to V. dahliae and R. solani, was selected by mini-Tn10 mutagenesis and in vitro virulence screening. The inserted gene in the mutant was cloned and identified as the phoR gene, which encodes a sensor kinase in the PhoP/PhoR two-component system. Compared to the wild-type strain, the APase activities of the mutant was decreased significantly when cultured in low phosphate medium, but no obvious difference was observed when cultured in high phosphate medium. The mutant also grew more slowly on organic phosphate agar and lost its phosphatidylcholine-solubilizing ability. The suppression of cotton seedling damping-off in vivo and colonization of the rhizosphere of cotton also decreased in the mutant strain when compared with the wild type strain. All of these characteristics could be partially restored by complementation of the phoR gene in the M216 mutant.

  19. In Vitro Screening for Abiotic Stress Tolerance in Potent Biocontrol and Plant Growth Promoting Strains of Pseudomonas and Bacillus spp.

    Science.gov (United States)

    Praveen Kumar, G; Mir Hassan Ahmed, S K; Desai, Suseelendra; Leo Daniel Amalraj, E; Rasul, Abdul

    2014-01-01

    Plant growth promoting rhizobacteria (PGPR) has been identified as a group of microbes that are used for plant growth enhancement and biocontrol for management of plant diseases. The inconsistency in performance of these bacteria from laboratory to field conditions is compounded due to the prevailing abiotic stresses in the field. Therefore, selection of bacterial strains with tolerance to abiotic stresses would benefit the end-user by successful establishment of the strain for showing desired effects. In this study we attempted to isolate and identify strains of Bacillus and Pseudomonas spp. with stress tolerance and proven ability to inhibit the growth of potential phytopathogenic fungi. Screening of bacterial strains for high temperature (50°C), salinity (7% NaCl), and drought (-1.2 MPa) showed that stress tolerance was pronounced less in Pseudomonas isolates than in Bacillus strains. The reason behind this could be the formation of endospores by Bacillus isolates. Tolerance to drought was high in Pseudomonas strains than the other two stresses. Three strains, P8, P20 and P21 showed both salinity and temperature tolerance. P59 strain possessed promising antagonistic activity and drought tolerance. The magnitude of antagonism shown by Bacillus isolates was also higher when compared to Pseudomonas strains. To conclude, identification of microbial candidate strains with stress tolerance and other added characteristic features would help the end-user obtain the desired beneficial effects.

  20. Parasitylenchus bifurcatus n. sp. (Tylenchida: Allantonematidae parasitizing Harmonia axyridis (Coleoptera: Coccinellidae

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    Poinar George O

    2012-10-01

    Full Text Available Abstract Background The harlequin ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae is native to central and eastern Asia and was purposely introduced into Europe to control aphids. While it proved to be a good biological control agent, its rapid spread and buildup of large populations made it a nuisance, since it overwinters in homes, emits unpleasant odors, stains fabrics, occasionally bites humans and feeds on apples, pears and grapes. Aside from the above, the ravenous appetite of H. axyridis results in their consumption of harmless native insects, including even other ladybird beetles. A study of the natural enemies of H. axyridis in Denmark revealed the presence of nematodes. The present study describes this nematode parasite and discusses aspects of its development and ecology. Methods Adult harlequin ladybird beetles were collected from March to November from four localities in Copenhagen on different plant species. In addition, groups of last-instar larvae and pupae (n = 50 were examined for the presence of nematodes. Living and recently dead nematodes were removed from adult H. axyridis in 0.5% saline solution, the nematodes were then heat killed (at 75C, fixed in 5% formalin and transferred to glycerin on slides for further examination and measurements. Results A new species of Allantonematidae (Tylenchida, Parasitylenchus bifurcatus n. sp., is described from adults of the harlequin ladybird, Harmonia axyridis in Denmark. The new species is characterized by a straight stylet lacking basal thickenings, a bursa and a forked tail tip in the vermiform (infective females and juvenile males. The new species is compared with P. coccinellinae previously described from ladybird beetles in France. Parasitism resulted in depletion of the fat body and partial or complete atrophy of the reproductive organs of the beetles. Infections occurred throughout the year with rates of parasitism reaching up to 35%. The rate increased to 60

  1. The SRAP based molecular diversity related to antifungal and antioxidant bioactive constituents for biocontrol potentials of Trichoderma against Sclerotium rolfsii Scc.

    Science.gov (United States)

    Hirpara, Darshna G; Gajera, H P; Bhimani, R D; Golakiya, B A

    2016-08-01

    The study was performed to examine 11 isolates of Trichoderma for their bio-control potentials against Sclerotium rolfsii Sacc. causing stem rot in groundnut. The antagonists Trichoderma were subjected to sequence related amplified polymorphism (SRAP) based molecular diversity analysis and compared with their hardness to S. rolfsii with respect to secretary antifungal and antioxidant profile. T. virens NBAII Tvs 12 evident highest (87.91 %) growth inhibition of test pathogen followed by T. koningii MTCC 796 (67.03 %) at 7 days after inoculation (DAI). Microscopic study confirmed biocontrol mechanism as mycoparasitism for Tvs 12 and antibiosis for MTCC 796. The growth inhibition of test pathogen was significantly negatively correlated with sclerotia formation and lipid peroxidation during antagonism due to release of secretary bioactive antioxidants by antagonists to terminate oxidative burst generated by S. rolfsii and causing inhibition of sclerotium formation. The GC-MS profile identified antifungal and antioxidant constituents hexadecane, 1,2-benzenedicarboxylic acid, mono (2-ethylhexyl) ester, 1-hexadecanesulfonyl chloride, and octadecane in potent antagonists Tvs 12; and nonacosane and octadecane in MTCC 796 along with two novel compounds 1-pentadecene and 1-heneicosyl formate for biocontrol activity. Molecular diversity of Trichoderma isolates associated with antagonistic activity was assessed by SRAP markers. The 115 primer combinations generate total 1328 amplified products of which, 1095 are shared polymorphic and 199 are unique polymorphic. The 15 SRAP combinations produced 18 bands to diagnose best antagonist Tvs 12 and 13 SRAP combinations generated 19 unique bands for identification of MTCC 796. The mycoparasitic antagonist Tvs 12 would be the best antagonist and released unique antifungal and antioxidant constituents to combat pathogen infection. The SRAP based genetic diversity indicates Tvs12 strain clustered with T. viride NBAII Tv23 and shared

  2. Requirement of Simultaneous Assessment of Crystal- and Supernatant-Related Entomotoxic Activities of Bacillus thuringiensis Strains for Biocontrol-Product Development

    Science.gov (United States)

    Argôlo-Filho, Ronaldo Costa; Costa, Robson Luz; Pinheiro, Daniele Heloisa; Corrêa, Fábio Mathias; Valicente, Fernando Hercos; Pomella, Alan William Vilela; Loguercio, Leandro Lopes

    2014-01-01

    Bioinsecticides with lower concentrations of endospores/crystals and without loss of efficiency are economically advantageous for pest biocontrol. In addition to Cry proteins, other Bacillus thuringiensis (Bt) toxins in culture supernatants (SN) have biocontrol potential (e.g., Vip3A, Cry1I, Sip1), whereas others are unwanted (β-exotoxins), as they display widespread toxicity across taxa. A strain simultaneously providing distinct toxin activities in crystals and SN would be desirable for bioinsecticides development; however, strains secreting β-exotoxins should be discarded, independently of other useful entomotoxins. Entomotoxicity of crystals and SN from a Brazilian Bt tolworthi strain (Btt01) was tested against Spodoptera frugiperda to assess the potential for biocontrol-product development based on more than one type of toxin/activity. Tests showed that 107 endospores mL−1 caused >80% of larvae mortality, suggesting Btt01 may be used in similar concentrations as those of other Bt-based biopesticides. When it was applied to cornfields, a significant 60% reduction of larvae infestation was observed. However, bioassays with Btt01 SN revealed a thermostable toxic activity. Physicochemical characterization strongly suggests the presence of unwanted β-exotoxins, with isolate-specific temporal variation in its secretion. Knowledge of the temporal pattern of secretion/activity in culture for all forms of toxins produced by a single strain is required to both detect useful activities and avoid the potential lack of identification of undesirable toxins. These findings are discussed in the contexts of commercial Bt product development, advantages of multiple-activity strains, and care and handling recommended for large-scale fermentation systems. PMID:24854738

  3. Endophytic fungal diversity in Theobroma cacao (cacao) and T. grandiflorum (cupuaçu) trees and their potential for growth promotion and biocontrol of black-pod disease.

    Science.gov (United States)

    Hanada, Rogério Eiji; Pomella, Alan William V; Costa, Heron Salazar; Bezerra, José Luiz; Loguercio, Leandro L; Pereira, José O

    2010-01-01

    The endophytic niches of plants are a rich source of microbes that can directly and indirectly promote plant protection, growth and development. The diversity of culturable endophytic fungi from stems and branches of Theobroma cacao (cacao) and Theobroma grandiflorum (cupuaçu) trees growing in the Amazon region of Brazil was assessed. The collection of fungal endophytic isolates obtained was applied in field experiments to evaluate their potential as biocontrol agents against Phytophthora palmivora, the causal agent of the black-pod rot disease of cacao, one of the most important pathogens in cocoa-producing regions worldwide. The isolated endophytic fungi from 60 traditional, farmer-planted, healthy cacao and 10 cupuaçu plants were cultured in PDA under conditions inducing sporulation. Isolates were classified based upon the morphological characteristics of their cultures and reproductive structures. Spore suspensions from a total of 103 isolates that could be classified at least up to genus level were tested against P. palmivora in pods attached to cacao trees in the field. Results indicated that ∼70% of isolates showed biocontrol effects to a certain extent, suggesting that culturable endophytic fungal biodiversity in this system is of a mostly mutualistic type of interaction with the host. Eight isolates from genera Trichoderma (reference isolate), Pestalotiopsis, Curvularia, Tolypocladium and Fusarium showed the highest level of activity against the pathogen, and were further characterized. All demonstrated their endophytic nature by colonizing axenic cacao plantlets, and confirmed their biocontrol activity on attached pods trials by showing significant decrease in disease severity in relation to the positive control. None, however, showed detectable growth-promotion effects. Aspects related to endophytic biodiversity and host-pathogen-endophyte interactions in the environment of this study were discussed on the context of developing sustainable strategies

  4. Requirement of simultaneous assessment of crystal- and supernatant-related entomotoxic activities of Bacillus thuringiensis strains for biocontrol-product development.

    Science.gov (United States)

    Argôlo-Filho, Ronaldo Costa; Costa, Robson Luz; Pinheiro, Daniele Heloisa; Corrêa, Fábio Mathias; Valicente, Fernando Hercos; Pomella, Alan William Vilela; Loguercio, Leandro Lopes

    2014-05-20

    Bioinsecticides with lower concentrations of endospores/crystals and without loss of efficiency are economically advantageous for pest biocontrol. In addition to Cry proteins, other Bacillus thuringiensis (Bt) toxins in culture supernatants (SN) have biocontrol potential (e.g., Vip3A, Cry1I, Sip1), whereas others are unwanted (β-exotoxins), as they display widespread toxicity across taxa. A strain simultaneously providing distinct toxin activities in crystals and SN would be desirable for bioinsecticides development; however, strains secreting β-exotoxins should be discarded, independently of other useful entomotoxins. Entomotoxicity of crystals and SN from a Brazilian Bt tolworthi strain (Btt01) was tested against Spodoptera frugiperda to assess the potential for biocontrol-product development based on more than one type of toxin/activity. Tests showed that 10(7) endospores mL(-1) caused >80% of larvae mortality, suggesting Btt01 may be used in similar concentrations as those of other Bt-based biopesticides. When it was applied to cornfields, a significant 60% reduction of larvae infestation was observed. However, bioassays with Btt01 SN revealed a thermostable toxic activity. Physicochemical characterization strongly suggests the presence of unwanted β-exotoxins, with isolate-specific temporal variation in its secretion. Knowledge of the temporal pattern of secretion/activity in culture for all forms of toxins produced by a single strain is required to both detect useful activities and avoid the potential lack of identification of undesirable toxins. These findings are discussed in the contexts of commercial Bt product development, advantages of multiple-activity strains, and care and handling recommended for large-scale fermentation systems.

  5. Requirement of Simultaneous Assessment of Crystal- and Supernatant-Related Entomotoxic Activities of Bacillus thuringiensis Strains for Biocontrol-Product Development

    Directory of Open Access Journals (Sweden)

    Ronaldo Costa Argôlo-Filho

    2014-05-01

    Full Text Available Bioinsecticides with lower concentrations of endospores/crystals and without loss of efficiency are economically advantageous for pest biocontrol. In addition to Cry proteins, other Bacillus thuringiensis (Bt toxins in culture supernatants (SN have biocontrol potential (e.g., Vip3A, Cry1I, Sip1, whereas others are unwanted (β-exotoxins, as they display widespread toxicity across taxa. A strain simultaneously providing distinct toxin activities in crystals and SN would be desirable for bioinsecticides development; however, strains secreting β-exotoxins should be discarded, independently of other useful entomotoxins. Entomotoxicity of crystals and SN from a Brazilian Bt tolworthi strain (Btt01 was tested against Spodoptera frugiperda to assess the potential for biocontrol-product development based on more than one type of toxin/activity. Tests showed that 107 endospores mL−1 caused >80% of larvae mortality, suggesting Btt01 may be used in similar concentrations as those of other Bt-based biopesticides. When it was applied to cornfields, a significant 60% reduction of larvae infestation was observed. However, bioassays with Btt01 SN revealed a thermostable toxic activity. Physicochemical characterization strongly suggests the presence of unwanted β-exotoxins, with isolate-specific temporal variation in its secretion. Knowledge of the temporal pattern of secretion/activity in culture for all forms of toxins produced by a single strain is required to both detect useful activities and avoid the potential lack of identification of undesirable toxins. These findings are discussed in the contexts of commercial Bt product development, advantages of multiple-activity strains, and care and handling recommended for large-scale fermentation systems.

  6. Soil type dependent rhizosphere competence and biocontrol of two bacterial inoculant strains and their effects on the rhizosphere microbial community of field-grown lettuce.

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    Susanne Schreiter

    Full Text Available Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 10(6 colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they

  7. Evaluación de microorganismos aislados de gallinaza por su potencial para el biocontrol de fusarium (f. oxysporum) en plántulas de uchuva (physalis peruviana).

    OpenAIRE

    Rodríguez Amézquita, Jorge Enrique; Velandia Monsalve, Jorge; Viteri Rosero, Silvio Edgar

    2011-01-01

    En Colombia, las pérdidas económicas ocasionadas por Fusarium oxysporum en el cultivo de uchuva son considerables. Se evaluaron hongos y bacterias aislados de 2 fuentes de gallinaza, su potencial como agentes de biocontrol de este patógeno. La evaluación se realizó en cajas de Petri con PDA para lo cual se colocó en el centro de las mismas, un disco de 5 mm de diámetro colonizado por el patógeno y a 3 cm del centro, sobre los ejes horizontal y vertical, cada uno de los aislamientos de la gall...

  8. Identification and application of biocontrol agents against Cotton leaf curl virus disease in Gossypium hirsutum under greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Memoona Ramzan

    2016-05-01

    Full Text Available Biological control is a novel approach in crop protection. Bacteria, such as Bacillus spp. and Pseudomonas spp., are reported for this purpose and some of their products are already commercially available. In this study, the rhizosphere and phyllosphere of healthy cotton plants were used as a source of bacterial isolates with properties of potential biocontrol agents. The isolates were screened for phosphate solubilization activity, indole acetic acid (IAA production and antifungal activity. Two isolates, S1HL3 and S1HL4, showed phosphate solubilization and IAA production simultaneously, while another two, JS2HR4 and JS3HR2, demonstrated potential to inhibit fungal pathogens. These bacteria were identified as Pseudomonas aeruginosa (S1HL3, Burkholderia sp. (S1HL4 and Bacillus sp. (JS2HR4 and JS3HR2 based on biochemical and molecular characteristics. The isolates were tested against Cotton leaf curl virus (CLCuV in greenhouse conditions, both as individual bacterial isolates and consortia. Treated plants were healthy as compared to control plants, where up to 74% of the plants were symptomatic for CLCuV infection. Maximum inhibition of CLCuV was observed in the plants treated with a mixture of bacterial isolates: the viral load in the treated plants was only 0.4% vs. up to 74% in controls. This treatment consortium included P. aeruginosa S1HL3, Burkholderia sp. S1HL4 and Bacillus spp. isolates, JS2HR4 and JS3HR2. The principal-component biplot showed a highly significant correlation between the viral load percentage and the disease incidence.

  9. Do biopesticides affect the demographic traits of a parasitoid wasp and its biocontrol services through sublethal effects?

    Directory of Open Access Journals (Sweden)

    Antonio Biondi

    Full Text Available Pesticide risk assessments are usually based on short-term acute toxicity tests, while longer-term population dynamic related traits, critical to the success of biological control and Integrated Pest Management (IPM programs, are often overlooked. This is increasingly important with respect to new biopesticides that frequently cause no short-term acute effects, but that can induce multiple physiological and behavioral sublethal effects, leading to a decrease in population growth and ecosystem services. In this study we assessed the lethal and sublethal effects of six biopesticides [abamectin, azadirachtin, Bacillus thuringiensis, borax plus citrus oil (Prev-Am®, emamectin benzoate, and spinosad], used in tomato crops to control the invasive pest Tuta absoluta (Lepidoptera: Gelechiidae, on adults and pupae of the parasitoid Bracon nigricans (Hymenoptera: Braconidae. Data on female survival and production of female offspring were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinosad caused 100% and 80% mortality in exposed adults (even 10 d after the treatment and pupae, respectively. Although most of the biopesticides had low levels of acute toxicity, multiple sublethal effects were observed. The biocontrol activity of both females that survived 1-h and 10-d old residues, and females that emerged from topically treated pupae was significantly affected by the application of the neurotoxic insecticides emamectin benzoate and abamectin. Furthermore, very low B. nigricans demographic growth indices were estimated for these two insecticides, indicating potential local extinction of the wasp populations. Among the tested products, Bt proved to be the safest for B. nigricans adults and pupae. Our findings emphasize that acute toxicity assessment alone cannot fully predict the actual impact of pesticides on non-target parasitoids. Thus, sublethal effects related to the species specific life

  10. Peptaibol, secondary-metabolite, and hydrophobin pattern of commercial biocontrol agents formulated with species of the Trichoderma harzianum complex.

    Science.gov (United States)

    Degenkolb, Thomas; Fog Nielsen, Kristian; Dieckmann, Ralf; Branco-Rocha, Fabiano; Chaverri, Priscila; Samuels, Gary J; Thrane, Ulf; von Döhren, Hans; Vilcinskas, Andreas; Brückner, Hans

    2015-04-01

    The production of bioactive polypeptides (peptaibiotics) in vivo is a sophisticated adaptation strategy of both mycoparasitic and saprotrophic Trichoderma species for colonizing and defending their natural habitats. This feature is of major practical importance, as the detection of peptaibiotics in plant-protective Trichoderma species, which are successfully used against economically relevant bacterial and fungal plant pathogens, certainly contributes to a better understanding of these complex antagonistic interactions. We analyzed five commercial biocontrol agents (BCAs), namely Canna(®) , Trichosan(®) , Vitalin(®) , Promot(®) WP, and TrichoMax(®) , formulated with recently described species of the Trichoderma harzianum complex, viz. T. afroharzianum, T. simmonsii, and T. guizhouense. By using the well-established, HPLC/MS-based peptaibiomics approach, it could unequivocally be demonstrated that all of these formulations contained new and recurrent peptaibols, i.e., peptaibiotics carrying an acetylated N-terminus, the C-terminus of which is reduced to a 1,2-amino alcohol. Their chain lengths, including the amino alcohol, were 11, 14, and 18 residues, respectively. Peptaibols were also to be the dominating secondary metabolites in plate cultures of the four strains obtained from four of the Trichoderma- based BCAs, contributing 95% of the UHPLC-UV/VIS peak areas and 99% of the total ion count MS peak area from solid media. Furthermore, species-specific hydrophobins, as well as non-peptaibiotic secondary metabolites, were detected, the latter being known for their antifungal, siderophore, or plant-growth-promoting activities. Notably, none of the isolates produced low-molecular weight mycotoxins.

  11. Chitinolytic Bacteria Isolated from Chili Rhizosphere: Chitinase Characterization and Its Application as Biocontrol for Whitefly (Bemisia tabaci Genn.

    Directory of Open Access Journals (Sweden)

    Nisa R. Mubarik

    2010-01-01

    Full Text Available Problem statement: Chitin, a common constituent of insect exoskeleton, could be hydrolyzed by chitinase. The research was conducted to screen chitinolytic rhizobacteria isolated from rhizosphere of chilli pepper and to determine their chitinase activity in degrading chitin of whitefly, Bemisia tabaci Genn. (Hemiptera: Aleyrodidae. Whitefly is recognized as an important pest on many crops including chilli pepper. Approach: Screening and molecular identification based on 16S rRNA sequence of chitinolytic isolates, chitinase productions, measurement of chitinase activity, characterization of chitinase and effect of the chitinase treatment on whitefly were studied. Results: A total of 25 isolates of rhizobacteria formed a clear zone on solid chitin media. Two isolates, i.e., I.5 and I.21 isolates had the highest chitinolytic index. Based on sequence of 16S rRNA gene, the isolates of I.5 and I.21 were identified as Bacillus sp. and Bacillus cereus, respectively. The highest chitinolytic index and specific activity of I.5 isolate was 0.94 and 0.11 U mg-1 proteins, respectively. Maximum production of I.5 chitinase was occured after 36 h cultivation at 30°C and pH 7.0. The highest chitinolytic index and specific activity of I.21isolate was 0.75 and 0.114 U mg-1 proteins, respectively. Maximum production of I.21 chitinase was occured after 36 h cultivation at 55°C and pH 7.0. Cell culture and crude enzyme of the isolates were tested on chitin of B. tabaci and the effect was observed using a microscope and sterile water was used as a negative control. Hydrolytic observation showed that crude enzyme of I.21 isolate could degrade chitin of B. tabaci exoskeleton and the activity was better than that of I.5 isolate. Conclusion: Chitinase produced by Bacillus cereus I.21 strain has potential application as biocontrol agents for B. tabaci.

  12. Can the halophilic ciliate Fabrea salina be used as a bio-control of microalgae blooms in solar salterns?

    Science.gov (United States)

    Hong, Hyun Pyo; Choi, Joong Ki

    2015-09-01

    The microlage Dunaliella salina, a major producer in salterns, is a serious problem for salt production. In this study we tried to assess if Fabrea salina can control D. salina. By parameterising numerical and functional response (growth and grazing vs prey abundance, respectively) at 90 psu and 30°C, where the ciliate is abundant and grows well, we developed a predator-prey model. The model is used to explore how change in microalga growth rate affect the dynamics, and the functional response is used in combination with field data to assess the potential impact of F. salina on D. salina. Over the 20 d simulation the ciliate controlled the prey population under all prey growth rates; although once D. salina were exhausted below the threshold level, F. salina died due to starvation, allowing the alga to increase in abundance, resulting in one or two predatorprey cycle, depending on prey growth rate. In general, the model predicted trends observed by others in the field, suggesting that it provided a good prediction of what may occur under the conditions we examined. Likewise we show that the ciliate can have a high impact on microalgal populations in the field. Finally, a literature review indicated that F. salina could be a good competitor with other protozoa and metazoan in salterns, depending on salinity and temperature, which requires further study and attention. In summary, we encourage continued studies on this unique ciliate on solar salterns and suggest that it may be useful in the bio-control of micoalgae.

  13. Evaluación de hongos y bacterias aislados de gallinaza en el biocontrol de Sclerotium cepivorum Berk

    Directory of Open Access Journals (Sweden)

    Gladys Amparo Sarmiento

    2013-07-01

    Full Text Available Objetivo. Seleccionar hongos y bacterias de la gallinaza por su capacidad antagónica en el biocontrol de S. cepivorum in vitro y en invernadero. Materiales y métodos. De dos fuentes de gallinaza, una pura y otra compuesta, se tomaron sendas muestras de 100 g, se colocaron en erlemeyers, se agregó agua destilada estéril hasta completar un litro y se agitó durante 5 minutos. A partir de esta suspensión se prepararon diluciones de 1x10-1 hasta 1x10-4, y se evaluó el crecimiento y esporulación de S. cepivorum. Los microorganismos seleccionados in vitro fueron evaluados en el control de la enfermedad en invernadero. Se evaluó la incidencia de la enfermedad y el porcentaje de plantas muertas. Resultados. De las dos fuentes de gallinaza se aislaron 13 colonias de hongos y 26 de bacterias, para un total de 39 aislamientos, de los cuales, tras ser evaluados in vitro, fueron seleccionados tres aislamientos de hongos (H2, H5, H6 y una bacteria (B21 por su capacidad antagónica a S. cepivorum, a los 6, 9, 12 y 15 días, y la producción de esclerocios, con diferencias altamente significativas en comparación con el testigo. Los aislamientos H2 y H6 corresponden al género Trichoderma; el H5, a Penicillium, y B21, a Bacillus. Con H2, H5, H6 y B21, los síntomas de la enfermedad fueron observados en la semana 13, con una incidencia del 20%, y en el testigo, en la semana novena, con una incidencia del 70%, y 40% de muerte de plántulas. Conclusión. Las gallinazas son una fuente de microorganismos biocontroladores de S. cepivorum.

  14. Ustilago maydis killer toxin as a new tool for the biocontrol of the wine spoilage yeast Brettanomyces bruxellensis.

    Science.gov (United States)

    Santos, Antonio; Navascués, Eva; Bravo, Enrique; Marquina, Domingo

    2011-01-31

    Brettanomyces bruxellensis is one of the most damaging species for wine quality, and tools for controlling its growth are limited. In this study, thirty-nine strains belonging to Saccharomyces cerevisiae and B. bruxellensis have been isolated from wineries, identified and then tested against a panel of thirty-nine killer yeasts. Here, for the first time, the killer activity of Ustilago maydis is proven to be effective against B. bruxellensis. Mixed cultures in winemaking conditions show that U. maydis CYC 1410 has the ability to inhibit B. bruxellensis, while S. cerevisiae is fully resistant to its killer activity, indicating that it could be used in wine fermentation to avoid the development of B. bruxellensis without undesirable effects on the fermentative yeast. The characterization of the dsRNAs isolated and purified from U. maydis CYC 1410 indicated that this strain produces a KP6-related toxin. Killer toxin extracts were active against B. bruxellensis at pH values between 3.0 and 4.5 and temperatures comprised between 15 °C and 25 °C, confirming their biocontrol activity in winemaking and wine aging conditions. Furthermore, small amounts (100 AU/ml) of killer toxin extracts from U. maydis significantly reduced the amount of 4-ethylphenol produced by B. bruxellensis, indicating that in addition to the growth inhibition observed for high killer toxin concentrations (ranging from 400 to 2000 AU/ml), small amounts of the toxin are able to reduce the production of volatile phenols responsible for the aroma defects in wines caused by B. bruxellensis.

  15. Functional analysis of the class II hydrophobin gene HFB2-6 from the biocontrol agent Trichoderma asperellum ACCC30536.

    Science.gov (United States)

    Huang, Ying; Mijiti, Gulijimila; Wang, Zhiying; Yu, Wenjing; Fan, Haijuan; Zhang, Rongshu; Liu, Zhihua

    2015-02-01

    A class II hydrophobin gene, HFB2-6, was cloned from Trichoderma asperellum ACCC30536 and its biocontrol function was studied. According to our previous transcriptome data, six of the eight class II hydrophobin genes were obviously differential expression in four inducing conditions, especially the gene HFB2-6. Moreover, HFB2-6 proven to be differentially transcribed under eight different treatments. HFB2-6 transcripts were up-regulated under 1% Alternaria alternata cell wall and 5% A. alternata fermentation liquid treatments, and by nutritional stress conditions, suggesting that HFB2-6 plays roles in interactions with both biotic and abiotic environmental conditions. HFB2-6 expression was down-regulated under 1% poplar leaf powder culture conditions, but its expression was up-regulated under 1% poplar root powder, indicating that HFB2-6 has a function in root colonization. Furthermore, the recombinant hydrophobin rHFB2-6 was successfully expressed in Escherichia coli BL21-HFB2-6 and purified from the recombinant strain. Genes related to both the jasmonic acid and salicylic acid signal transduction pathways were up-regulated by interaction with renatured rHFB2-6. The ORCA3 (octadecanoid-derivative responsive Catharanthus AP2-domain) gene of the poplar jasmonic acid signal transduction pathway showed a peak expression of 4.48 times at 2 h, and the peak expression of PR1 (pathogenesis-related protein gene) in the salicylic acid signal transduction pathway was 4.58 times at 72 h. Two genes, MP (monopteros) and GH3.17 (auxin original response gene), in the auxin signal transduction pathway were also up-regulated after induction with rHFB2-6, indicating that rHFB2-6 can promote poplar growth and confer broad-spectrum resistance to pathogens.

  16. Influence of container design on predation rate of potential biocontrol agent, Toxorhynchites splendens (Diptera: Culicidae) against dengue vector.

    Science.gov (United States)

    Mohamad, N; Zuharah, W F

    2014-03-01

    Toxorhynchites splendens larvae are a natural predator of dengue vector mosquito larvae, Aedes albopictus. This study was carried out to evaluate the predation rate of Tx. splendens third instar larvae on Ae. albopictus larvae in 24 h. Each predator was offered prey at a density between 10 to 50 individuals. Predation rate of Tx. splendens were also tested with two manipulated factors; various types of container and different water volumes. The experiment was evaluated in man-made containers (tin cans, plastic drinking glasses and rubber tires) and natural container (bamboo stumps) which were filled with different water volumes (full, half full, 1/4 full, and 1/8 full). The prey density and the characteristics of the container were found as significant factors which influence the predation rate of Tx. splendens. The predator consumed significantly more prey at higher prey densities (40 and 50 preys) compared to the lowest density (10 preys) (F=3.935, df=4, p=0.008). The results showed significantly higher consumption in horizontal shaped container of rubber tire than in vertical shape of bamboo stumps (F=3.100, df=3, p=0.029). However, the water volume had no significant effect on predation rate of Tx. splendens (F=1.736, df=3, p=0.162). We generally suggest that Tx. splendens is best to be released in discarded tires or any other containers with horizontal shape design with wide opening since Tx. splendens can become more effective in searching prey in this type of container design. This predator is also a suitable biocontrol candidates to be introduced either in wet and dry seasons in Malaysia.

  17. Variations on conserved signaling pathways in biocontrol and development:G protein and MAPK genes of Trichoderma.atroviride and T.virens

    Institute of Scientific and Technical Information of China (English)

    Benjiamin A Horwitz

    2004-01-01

    @@ Filamentous fungi employ conserved eukaryotic signaling pathway to detect and respond to environmental signals, including the presence of the host. Genetic experiment in which a particular signaling protein is lost, or its activity enhanced, have defined some of the function of heterotrimeric G proteins and MAP kinases in development and virulence. A hallmark of these studies is that orthologs in different species may have different functions. Antagonistic fungal-fungal interactions form the basis for biological control of plant disease. These interactions may employ novel modes of regulation by conserved signaling elements. Tag1, a G protein a subunit of Trichoderma. atroviride belonging to fungal Gi class, is involved in repression of sporulation and hyphal coiling(1). Deletion of ortholog of this gene, TgaA, in Trichoderma (Gliocladium) virens, however, did not affect sporulation and growth, yet tgaA mutants are unable to parasitize S. rolfsii sclerotia(2). Mutation of a second G αsubunit gene is now under study. TmkA, a MAPK gene of T. virens, is involved in biocontrol properties and repression of conidiation (3). Using suppression-subtraction hybridization and other approaches, we are beginning to identify additional elements of the signaling cascades and their downsteam targets. The role of G protein and MAPK genes are sometimes specific to a particular host fungus or to parasitism of mycelia or sclerotia (2, 3). Also of relevance to biocontrol, signal transduction pathway provide a means to alter the balance between sporulation, mycelial growth and hyphal coiling.

  18. A phenazine-1-carboxylic acid producing polyextremophilic Pseudomonas chlororaphis (MCC2693) strain, isolated from mountain ecosystem, possesses biocontrol and plant growth promotion abilities.

    Science.gov (United States)

    Jain, Rahul; Pandey, Anita

    2016-09-01

    The genus Pseudomonas is known to comprise a huge diversity of species with the ability to thrive in different habitats, including those considered as extreme environments. In the present study, a psychrotolerant, wide pH tolerant and halotolerant strain of Pseudomonas chlororaphis GBPI_507 (MCC2693), isolated from the wheat rhizosphere growing in a mountain location in Indian Himalayan Region (IHR), has been investigated for its antimicrobial potential with particular reference to phenazine production and plant growth promoting traits. GBPI_507 showed phenazine production at the temperatures ranged from 14 to 25°C. The benzene extracted compound identified as phenazine-1-carboxylic acid (PCA) through GC-MS exhibited antimicrobial properties against Gram positive bacteria and actinomycetes. The inhibition of phytopathogens in diffusible biocontrol assays was recorded in an order: Alternaria alternata>Phytophthora sp.>Fusarium solani>F. oxysporum. In volatile metabolite assays, all the pathogens, except Phytophthora sp. produced distorted colonies, characterized by restricted sporulation. The isolate also possessed other growth promoting and biocontrol traits including phosphate solubilization and production of siderophores, HCN, ammonia, and lytic enzymes (lipase and protease). Molecular studies confirmed production of PCA by the bacterium GBPI_507 through presence of phzCD and phzE genes in its genome. The polyextremophilic bacterial strain possesses various important characters to consider it as a potential agent for field applications, especially in mountain ecosystem, for sustainable and eco-friendly crop production.

  19. The Transition from a Phytopathogenic Smut Ancestor to an Anamorphic Biocontrol Agent Deciphered by Comparative Whole-Genome Analysis[W][OPEN

    Science.gov (United States)

    Lefebvre, François; Joly, David L.; Labbé, Caroline; Teichmann, Beate; Linning, Rob; Belzile, François; Bakkeren, Guus; Bélanger, Richard R.

    2013-01-01

    Pseudozyma flocculosa is related to the model plant pathogen Ustilago maydis yet is not a phytopathogen but rather a biocontrol agent of powdery mildews; this relationship makes it unique for the study of the evolution of plant pathogenicity factors. The P. flocculosa genome of ∼23 Mb includes 6877 predicted protein coding genes. Genome features, including hallmarks of pathogenicity, are very similar in P. flocculosa and U. maydis, Sporisorium reilianum, and Ustilago hordei. Furthermore, P. flocculosa, a strict anamorph, revealed conserved and seemingly intact mating-type and meiosis loci typical of Ustilaginales. By contrast, we observed the loss of a specific subset of candidate secreted effector proteins reported to influence virulence in U. maydis as the singular divergence that could explain its nonpathogenic nature. These results suggest that P. flocculosa could have once been a virulent smut fungus that lost the specific effectors necessary for host compatibility. Interestingly, the biocontrol agent appears to have acquired genes encoding secreted proteins not found in the compared Ustilaginales, including necrosis-inducing-Phytophthora-protein- and Lysin-motif- containing proteins believed to have direct relevance to its lifestyle. The genome sequence should contribute to new insights into the subtle genetic differences that can lead to drastic changes in fungal pathogen lifestyles. PMID:23800965

  20. Interspecific Interactions between the Invasive Beetle Harmonia axyridis, Native Anthocorids and Entomopathogenic Fungi

    DEFF Research Database (Denmark)

    Howe, Andrew Gordon

    . The harlequin ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae) was introduced to North America from Asia in the early 20th century as a biological control agent against insect agricultural pests. In the late 20th century a specific population in eastern North America became invasive. Invasive H...... that an invasive eastern North American and native Chinese population displayed greater dispersal activity than three other populations. Although an invasive/native dichotomy was not established, results suggest that trait differences may reflect population-level adaptions. Findings underline that intraspecific...

  1. Wonder world of phages: potential biocontrol agents safeguarding biosphere and health of animals and humans- current scenario and perspectives.

    Science.gov (United States)

    Tiwari, Ruchi; Chakraborty, Sandip; Dhama, Kuldeep; Wani, Mohd Yaqoob; Kumar, Amit; Kapoor, Sanjay

    2014-02-01

    Darwin's theory of natural selection and concept of survival of fittest of Wallace is a universal truth which derives the force of life among all live entities on this biosphere. Issues regarding food safety along with increased drug resistance and emerging zoonotic infections have proved that multidisciplinary efforts are in demand for human and animal welfare. This has led to development of various novel therapies the list of which remains incomplete without mentioning about phages. Homologous and non-homologous recombination along with point mutation and addition of new genes play role in their evolution. The rapid emergence of the antibiotic resistant strains of bacteria have created keen interest in finding necessary alternatives to check microbial infections and there comes the importance of phages. Phages kill the bacteria either by lysis or by releasing holins. Bacteriophages; the viruses that live on bacteria are nowadays considered as the best biocontrol agents. They are used as replacers of antibiotics; food industry promoter; guard of aquatic life as well as of plants; pre-slaughter treatment agents; Generally Recognized As Safe (GRAS) food additives; Typing agent of bacteria; active tool of super bug therapy; in post harvest crops and food and during post infection and also to combat intracellular pathogens viz. Mycobacteria and Mycoplasma. Cyanophages/phycophages are particularly useful in controlling blooms produced by various genera of algae and cyanobacteria. By performing centrifugation studies and based on electron microscopy certain virus like particles containing ds RNA have been confirmed as mycophages. They are well proven as threat to pathogenic fungi (both fungal hyphae and yeast). Those that infect yeasts are called zymophages. Virophages have exquisite specificity for their viral host, hence can extensively be used for genetic studies and can also act as evolutionary link. After the discovery of very first virophage till now, a total of 3

  2. Sporulation of several biocontrol fungi as affected by carbon and nitrogen sources in a two-stage cultivation system.

    Science.gov (United States)

    Gao, Li; Liu, Xingzhong

    2010-12-01

    The development of fungal biopesticides requires the efficient production of large numbers spores or other propagules. The current study used published information concerning carbon concentrations and C:N ratios to evaluate the effects of carbon and nitrogen sources on sporulation of Paecilomyces lilacinus (IPC-P and M-14) and Metarhizium anisopliae (SQZ-1-21 and RS-4-1) in a two-stage cultivation system. For P. lilacinus IPCP, the optimal sporulation medium contained urea as the nitrogen source, dextrin as the carbon source at 1 g/L, a C:N ratio of 5:1, with ZnSO(4)·7H(2)O at 10 mg/L and CaCl(2) at 3 g/L. The optimal sporulation medium for P. lilacinus M-14 contained soy peptone as the nitrogen source and maltose as the carbon source at 2 g/L, a C:N ratio of 10:1, with ZnSO(4)·7H(2)O at 250 mg/L, CuSO(4)·5H(2)O at 10 mg/L, H(3)BO(4) at 5 mg/L, and Na(2)MoO(4)·2H(2)O at 5 mg/L. The optimum sporulation medium for M. anisopliae SQZ-1-21 contained urea as the nitrogen source, sucrose as the carbon source at 16 g/ L, a C:N ratio of 80:1, with ZnSO(4)·7H(2)O at 50 mg/L, CuSO(4)·5H(2)O at 50 mg/L, H(3)BO(4) at 5 mg/L, and MnSO(4)·H(2)O at 10 mg/L. The optimum sporulation medium for M. anisopliae RS-4-1 contained soy peptone as the nitrogen source, sucrose as the carbon source at 4 g/L, a C:N ratio of 5:1, with ZnSO(4)·7H(2)O at 50 mg/L and H(3)BO(4) at 50 mg/L. All sporulation media contained 17 g/L agar. While these results were empirically derived, they provide a first step toward low-cost mass production of these biocontrol agents.

  3. Effects of actinomyces bio-control on growth of cucumber%生防放线菌对黄瓜生长效应的影响

    Institute of Scientific and Technical Information of China (English)

    禚苏; 郑璐; 张丽琼

    2011-01-01

    [Objective]The present experiment was conducted to study the effect of actinomyces bio-control on growth of cucumber to offer the reference on cultivation and disease control in cucumber plantations. [Method]Different mixed ratios of bio-control actinomyces and plant ash (1:50,1 :25,1:10) used for coating cucumber seeds were designed to investigate their effects on seed germination, plant height, root length and physiological and chemical characteristics of cucumber. [Result] Bio-control actinomyces had inhibitory effects on germination of cucumber, while suitable concentration of actinomycetes preparations promoted the growth of plant, improved the plant height and root length, and increased the chlorophyll content and activities of CAT and nitrate reductase in leaves. [Conclusion]The actinomycetes and plant ash in ratio of 1:25 used to coat seeds was found most favorable to enhance the yield, quality and economic benefits.%[目的]研究生防放线菌与草木灰混合包农黄瓜种子对黄瓜的生长效应,为黄瓜栽培与病害防治提供理论依据.[方法]设生防放线菌与草木灰1:50、1:25、1:10及纯草木灰混合包衣黄瓜种子处理,探讨不同比例的生防放线菌对黄瓜种子出苗、黄瓜幼苗株高、根长及生理生化指标的影响.[结果]生防放线菌对黄瓜出苗有抑制作用,但适宜浓度的生防放线菌制剂能促进黄瓜幼苗株高和根的生长,提高叶片叶绿素含量和过氧化氧酶及硝酸还原酶活性.[结论]在黄瓜生产中,可以采用生防放线菌制剂:草木灰=1:25的菌粉包衣黄瓜种子,以提高黄瓜的产量和品质,提高黄瓜种植的经济效益.

  4. Typhlodromus pyri and Euseius finlandicus (Acari: Phytoseiidae) as potential biocontrol agents against spider mites (Acari: Tetranychidae) inhabiting willows: laboratory studies on predator development and reproduction on four diets.

    Science.gov (United States)

    Puchalska, Ewa K; Kozak, Marcin

    2016-01-01

    Typhlodromus pyri Scheuten and Euseius finlandicus (Oudemans) are important predators of phytophagous mites. The present laboratory study aimed to determine whether both species can develop and reach maturity feeding on spider mites occurring on willows, i.e., Schizotetranychus schizopus (Zacher), Schizotetranychus garmani Pritchard & Baker, and Tetranychus urticae Koch, and on Brassica napus L. pollen. The predators' development, reproduction and demographic parameters were significantly affected by diet. The data suggest that rape pollen can be useful in mass rearing of E. finlandicus but is completely unsuitable as alternative food for T. pyri. Short development time and high values of population parameters achieved by T. pyri feeding on larvae and protonymphs of S. schizopus and by E. finlandicus feeding on juvenile stages of S. garmani indicate great suitability of these preys as food for the phytoseiids, and make both predatory species promising biocontrol agents in spider mite control on willows.

  5. Bacterial Feeders, the Nematode Caenorhabditis elegans and the Flagellate Cercomonas longicauda, have different Effects on Outcome of Competition among the Pseudomonas Biocontrol Strains CHA0 and DSS73

    DEFF Research Database (Denmark)

    Pedersen, Annette; Nybroe, Ole; Winding, Anne;

    2009-01-01

    selective feeding flagellate Cercomonas longicauda versus the non-selective feeding nematode Caenorhabditis elegans) influence the abundance of two bacteria that compete for resources in simple model communities. Microcosms consisted of either one gfp-tagged bacterial strain (Pseudomonas fluorescens DSM......50090 or one of two biocontrol strains P. fluorescens CHA0 or Pseudomonas sp. DSS73) or combinations of two bacterial strains. DSM50090 is a suitable food bacterium, DSS73 is of intermediate food quality, and CHA0 is inedible to the bacterial feeders. Bacterial and protozoan cell numbers were measured......How bacterial feeding fauna affects colonization and survival of bacteria in soil is not well understood, which constrains the applicability of bacterial inoculants in agriculture. This study aimed to unravel how food quality of bacteria and bacterial feeders with different feeding habits (the...

  6. Complete genome sequence of the biocontrol strain Pseudomonas protegens Cab57 discovered in Japan reveals strain-specific diversity of this species.

    Directory of Open Access Journals (Sweden)

    Kasumi Takeuchi

    Full Text Available The biocontrol strain Pseudomonas sp. Cab57 was isolated from the rhizosphere of shepherd's purse growing in a field in Hokkaido by screening the antibiotic producers. The whole genome sequence of this strain was obtained by paired-end and whole-genome shotgun sequencing, and the gaps between the contigs were closed using gap-spanning PCR products. The P. sp. Cab57 genome is organized into a single circular chromosome with 6,827,892 bp, 63.3% G+C content, and 6,186 predicted protein-coding sequences. Based on 16S rRNA gene analysis and whole genome analysis, strain Cab57 was identified as P. protegens. As reported in P. protegens CHA0 and Pf-5, four gene clusters (phl, prn, plt, and hcn encoding the typical antibiotic metabolites and the reported genes associated with Gac/Rsm signal transduction pathway of these strains are fully conserved in the Cab57 genome. Actually strain Cab57 exhibited typical Gac/Rsm activities and antibiotic production, and these activities were enhanced by knocking out the retS gene (for a sensor kinase acting as an antagonist of GacS. Two large segments (79 and 115 kb lacking in the Cab57 genome, as compared with the Pf-5 genome, accounted for the majority of the difference (247 kb between these genomes. One of these segments was the complete rhizoxin analog biosynthesis gene cluster (ca. 79 kb and another one was the 115-kb mobile genomic island. A whole genome comparison of those relative strains revealed that each strain has unique gene clusters involved in metabolism such as nitrite/nitrate assimilation, which was identified in the Cab57 genome. These findings suggest that P. protegens is a ubiquitous bacterium that controls its biocontrol traits while building up strain-specific genomic repertoires for the biosynthesis of secondary metabolites and niche adaptation.

  7. The Pochonia chlamydosporia serine protease gene vcp1 is subject to regulation by carbon, nitrogen and pH: implications for nematode biocontrol.

    Directory of Open Access Journals (Sweden)

    Elaine Ward

    Full Text Available The alkaline serine protease VCP1 of the fungus Pochonia chlamydosporia belongs to a family of subtilisin-like enzymes that are involved in infection of nematode and insect hosts. It is involved early in the infection process, removing the outer proteinaceous vitelline membrane of nematode eggs. Little is known about the regulation of this gene, even though an understanding of how nutrients and other factors affect its expression is critical for ensuring its efficacy as a biocontrol agent. This paper provides new information on the regulation of vcp1 expression. Sequence analysis of the upstream regulatory region of this gene in 30 isolates revealed that it was highly conserved and contained sequence motifs characteristic of genes that are subject to carbon, nitrogen and pH-regulation. Expression studies, monitoring enzyme activity and mRNA, confirmed that these factors affect VCP1 production. As expected, glucose reduced VCP1 expression and for a few hours so did ammonium chloride. Surprisingly, however, by 24 h VCP1 levels were increased in the presence of ammonium chloride for most isolates. Ambient pH also regulated VCP1 expression, with most isolates producing more VCP1 under alkaline conditions. There were some differences in the response of one isolate with a distinctive upstream sequence including a variant regulatory-motif profile. Cryo-scanning electron microscopy studies indicated that the presence of nematode eggs stimulates VCP1 production by P. chlamydosporia, but only where the two are in close contact. Overall, the results indicate that readily-metabolisable carbon sources and unfavourable pH in the rhizosphere/egg-mass environment may compromise nematode parasitism by P. chlamydosporia. However, contrary to previous indications using other nematophagous and entomopathogenic fungi, ammonium nitrate (e.g. from fertilizers may enhance biocontrol potential in some circumstances.

  8. Biocontrol Potential of Streptomyces hydrogenans Strain DH16 toward Alternaria brassicicola to Control Damping Off and Black Leaf Spot of Raphanus sativus

    Science.gov (United States)

    Manhas, Rajesh K.; Kaur, Talwinder

    2016-01-01

    Biocontrol agents and their bioactive metabolites provide one of the best alternatives to decrease the use of chemical pesticides. In light of this, the present investigation reports the biocontrol potential of Streptomyces hydrogenans DH16 and its metabolites towards Alternaria brassicicola, causal agent of black leaf spot and damping off of seedlings of crucifers. In vitro antibiosis of strain against pathogen revealed complete suppression of mycelial growth of pathogen, grown in potato dextrose broth supplemented with culture supernatant (20% v/v) of S. hydrogenans DH16. Microscopic examination of the fungal growth showed severe morphological abnormalities in the mycelium caused by antifungal metabolites. In vivo studies showed the efficacy of streptomycete cells and culture supernatant as seed dressings to control damping off of Raphanus sativus seedlings. Treatment of pathogen infested seeds with culture supernatant (10%) and streptomycete cells significantly improved seed germination (75–80%) and vigor index (1167–1538). Furthermore, potential of cells and culture supernatant as foliar treatment to control black leaf spot was also evaluated. Clearly visible symptoms of disease were observed in the control plants with 66.81% disease incidence and retarded growth of root system. However, disease incidence reduced to 6.78 and 1.47% in plants treated with antagonist and its metabolites, respectively. Additionally, treatment of seeds and plants with streptomycete stimulated various growth traits of plants over uninoculated control plants in the absence of pathogen challenge. These results indicate that S. hydrogenans and its culture metabolites can be developed as biofungicides as seed dressings to control seed borne pathogens, and as sprays to control black leaf spot of crucifers. PMID:28018402

  9. In Vitro Evaluation Of Selected Plant Extracts As Biocontrol Agents Against Black Mold Aspergillus Niger Van Tieghem Of Onion Bulbs Allium Cepa L.

    Directory of Open Access Journals (Sweden)

    Saifeldin A. F. El-Nagerabi

    2015-08-01

    Full Text Available Black mold disease caused by Aspergillus niger V. Tiegh. is the most devastating infection occurs in onions Allium cepa L. under field and store conditions. The use of biocontrol agents is ecofriendly approach for controlling seedborne and soilborne diseases compared to the use of toxic synthetic fungicides. This study has been designed to assess the contamination levels of onion seeds with A. niger and its effect on seed germination and to evaluate the in vitro antifungal activity of Prunus mahaleb seeds Commiphora myrrha resin 0.5 1.0 1.5 2.0 g100 ml Syzygium aromaticum dry buds clove and Panax ginseng roots extracts 0.5 1.0 2.0 2.5 g100 ml against black mold of onion bulbs. The fungus is seedborne pathogen which significantly contaminated onion seeds 89-100 and reduced seed germination 39-83. The extracts of clove caused 43-96 inhibition in spore germination followed by mahaleb 37-96 myrrha 33-88 and ginseng 34-87. The highest concentration of these extracts 3.0 did not affect seed germination but significantly reduced seed contamination by A. niger up to 84 80 71 and 65 for Syzygium aromaticum Syzygium aromaticum Panax ginseng and Prunus mahaleb respectively. The extracts apparently inhibited the fungal growth and mold development on stored onion bulbs which indicates the antifungal property of these extracts against A. niger. Therefore they can be recommended as effective biocontrol agents to reduce seed contamination and enhance the storability of onion bulbs. Thus the use of healthy and certified seeds for onion production is a priority.

  10. Bacillomycin L and surfactin contribute synergistically to the phenotypic features of Bacillus subtilis 916 and the biocontrol of rice sheath blight induced by Rhizoctonia solani.

    Science.gov (United States)

    Luo, Chuping; Zhou, Huafei; Zou, Jincheng; Wang, Xiaoyu; Zhang, Rongsheng; Xiang, Yaping; Chen, Zhiyi

    2015-02-01

    The antagonistic activity of lipopeptides in Bacillus subtilis 916 has been well documented, yet relatively little is known about their mechanism in biofilm formation and environmental colonization. This study sought to examine the interaction of B. subtilis 916 on Rhizoctonia solani-infected rice sheath to elucidate the mechanism of colonization on plant leaves. Results showed that the mutants Δbac, Δsrf, and Δsrf + bac of B. subtilis 916, deficient in bacillomycin L and surfactin production, respectively, not only altered colony morphology but also changed swarming motility, reduced antagonistic activity, and decreased biofilm formation. In particular, biofilm formation in mutant Δbac, not Δsrf or Δsrf + bac, were restored with addition of surfactin and bacillomycin L at 10 and 50 μg/mL, respectively. Moreover, surfactin and bacillomycin L were able to restore or enhance swarming motility in the corresponding mutants at 10 μg/mL, respectively. With the aid of green fluorescent protein tagging, it was demonstrated that B. subtilis 916 formed a robust biofilm on the rice sheath blight lesion and colonized well on R. solani-infected rice sheath, while its corresponding mutants performed poorly. These observations also correlated with the rice cultivar pot experiments, in which B. subtilis 916 exhibited greater biocontrol than its mutants. Our results suggest that surfactin and bacillomycin L contribute differently but synergistically to the biocontrol of rice sheath blight in B. subtilis 916 through its antifungal activity, biofilm formation, and colonization.

  11. Biocontrol of Botrytis allii Munn the Causal Agent of Neck Rot, the Post Harvest Disease in Onion, by use of a New Iranian Isolate of Streptomyces

    Directory of Open Access Journals (Sweden)

    M. Jorjandi

    2009-01-01

    Full Text Available Problem statement: Soil actinomycetes particularly Streptomyces spp. showed antagonistic activity against wide range of plant pathogens. In the recent decades they have attracted high interests as biocontrol agents. Onion neck rot or gray mold caused by Botrytis allii have imposed economic post harvest damages to onion bulbs and decreased its storage durability and market value. Approach: To investigate for biocontrol means against the pathogen, antagonistic activity of 50 isolates of soil Actinomycetes were assayed through agar disk method and dual culture bioassays. Active isolates were exposed to chloroform for detection of antibiotic. Minimum Inhibitory Concentration (MIC value and solubility of active crude extract in organic solvents were determined for Streptomyces isolate No. 347 which showed a unique and stable property of inhibiting Botrytis allii. To investigate the antagonistic effect of Streptomyces isolate No. 347 on control of onion gray mold, 4 different treatments were tested by means of Tukey HSD test. Results: From the tested isolates, 13 showed anti gray mold activities. Exposure of active isolates to chloroform revealed that Streptomyces isolates No. 347, 263 and 350 retained their antifungal activities. The active metabolite(s of Streptomyces isolate No. 347 was polar, soluble in H2O but insoluble in chloroform and methanol. MIC of the crude was determined as 0.05 mg mL-1 against B. allii. Stability of the active crude in distilled water at room temperature (12-30°C was about 6 months. Statistical studies indicated that Streptomyces isolates No. 347 can decrease losses of neck rot with significant level (pConclusion: The future goals include investigation of the antifungal genes in active isolates as candidates for genetic engineering of onion for increased tolerance against B. allii.

  12. Biocontrol Potential of Streptomyces hydrogenans strain DH16 Towards Alternaria brassicicola to Control Damping Off and Black Leaf Spot of Raphanus sativus

    Directory of Open Access Journals (Sweden)

    Rajesh Kumari Manhas

    2016-12-01

    Full Text Available Biocontrol agents and their bioactive metabolites provide one of the best alternatives to decrease the use of chemical pesticides. In light of this, the present investigation reports the biocontrol potential of Streptomyces hydrogenans DH16 and its metabolites towards Alternaria brassicicola, causal agent of black leaf spot and damping off of seedlings of crucifers. In vitro antibiosis of strain against pathogen revealed complete suppression of mycelial growth of pathogen, grown in potato dextrose broth supplemented with culture supernatant (20% v/v of Streptomyces hydrogenans DH16. Microscopic examination of the fungal growth showed severe morphological abnormalities in the mycelium caused by antifungal metabolites. In vivo studies showed the efficacy of streptomycete cells and culture supernatant as seed dressings to control damping off of Raphanus sativus seedlings. Treatment of pathogen infested seeds with culture supernatant (10% and streptomycete cells significantly improved seed germination (75-80% and vigour index (1167-1538. Furthermore, potential of cells and culture supernatant as foliar treatment to control black leaf spot was also evaluated. Clearly visible symptoms of disease were observed in the control plants with 66.81% disease incidence and retarded growth of root system. However, disease incidence reduced to 6.78 and 1.47% in plants treated with antagonist and its metabolites, respectively. Additionally, treatment of seeds and plants with streptomycete stimulated various growth traits of plants over uninoculated control plants in the absence of pathogen challenge. These results indicate that S. hydrogenans and its culture metabolites can be developed as biofungicides as seed dressings to control seed borne pathogens, and as sprays to control black leaf spot of crucifers.

  13. ADHERENCE AND PA THOGENICITY ASSA Y OF VIBRIO HARVE YI IN TIGER SHRIMP (PENAEUS MONODON LARVAE FOR SC REENING BIOCONTROL AGE NT

    Directory of Open Access Journals (Sweden)

    YUSMINAH H ALA

    2002-01-01

    Full Text Available Rifampicin-resistant marker w as empl oyed as a repor ter t o detect the ad here nce and colonization of V. harve yi in s hrimp larvae. Vibri o h arve yi P1B and YA3 2. 2 were isolated f rom dead s hrimp la rv ae i n Besuki, Norther n C oast of East Jav a, while V. harveyi HB3, was isolated from pris tine sea water in Pacita n, S outhe rn Coast of E ast Ja va . Vi brio metsc hnikovii used a s bioc ontr ol a gent was i solated fr om healthy shrimp larvae in Serang, We st Java. Spontane ous mutation was c onducted to generate V. harveyi P1B, YA32.2 and HB3 resistant to rifampi cin. These mutants exhibit ed similar survival ability to t heir parent al (wild type strai ns. Signifi cant larval mortalit y was o bserv ed i n s hrimp l arv ae i noculated with YA32.2 than that of larvae ino culated with P1B. Larvae inoculated with H B 3 showed the lo w est mortality. Bacterial cell c ount of Vi brio Rf* in dead larvae w ere 103-104 cells/larvae. Isolates of Vi brio metschnikovii Z an d M as biocontrol candid ates effectively r educed the growth a nd a dherence ability of YA32.2 t o shrimp larvae. Larval mort ality in rearing water inoculat ed simultaneousl y w ith YA32.2 and V. metschnikovii was lower than the one inoculated with YA32.2 alone. Therefore, Vibrio metschnikovii Z or M could be develope d as an effective pro biotic or biocontrol agent for V. harvey i in shrimp hatcheri es.

  14. Colonization and degradation of senescent flowers of zucchini squash by Trichoderma harzianum YC459, a biocontrol agent of gray mold, Botrytis cinerea

    Institute of Scientific and Technical Information of China (English)

    Geun Gon Kim; Young Ryun Chung

    2004-01-01

    @@ In commercial greenhouses, senescent flower petals or flowers of vegetables such as tomato,strawberry, hot pepper and zucchini squash were blighted to be removed from fruits within five days after spraying of Trichoderna harzianun YC459 (TORY() , JGreen Inc.), a biocontrol agent with good and consistent efficacy as chemical fungicides for the control of gray mold rot caused by B.cinerea. The mechanism for selective colonization of senescent floral tissues by T. harzianum YCA59was elucidated using fresh and senescent (4 days and 14 days after pollination, respectively) floral tissues of zucchini squash (Cucurbita moschata Duchesne) . The spores of T. harzianum YCA59were produced much more on water agar and liquid culture media supplemented with 5% dry powder of senescent floral tissues than with fresh tissues during 15 days incubation. Mycelial growth was also much better in the media with senescent tissues than with fresh tissues. Enzyme activities of carboxymethyl cellulase, amylase and polygalacturonase in the liquid media, which might be involved in the colonization and degradation of tissues by T. harzianum YCA59 were compared. The activities of three enzymes were significantly higher in the media with senescent floral tissues than with fresh floral tissues reaching to the maximum during 9 to 12 days of incubation. Especially, the activities of carboxymethyl cellulase and polygalacturonase of T. harzianum YC459 were much higher than those of other Trichoderma species, T. asperellum, T. viride and T. koningii in the liquid media with senescent floral tissues. Based on the results, the selective colonization and degradation of senescent floral tissues, an important habitat for B. cinerea, may be another mechanism for the biocontrol of gray mold rot of vegetables by T. harzianurm YC459.

  15. Real-time RT-PCR expression analysis of chitinase and endoglucanase genes in the three-way interaction between the biocontrol strain Clonostachys rosea IK726, Botrytis cinera and strawberry

    DEFF Research Database (Denmark)

    Mamarabadi, Mojtaba; Jensen, Birgit; Jensen, Søren Dan Funck

    2008-01-01

    Clonostachys rosea is a well-known biocontrol agent against Botrytis cinerea, the causal agent of gray mold in strawberry. The activity of cell wall-degrading enzymes might play a significant role for successful biocontrol by C. rosea. The expression pattern of four chitinases, and two...... endoglucanase genes from C. rosea strain IK726 was analyzed using real-time RT-PCR in vitro and in strawberry leaves during interaction with B. cinerea. Specific primers were designed for ß-tubulin genes from C. rosea and B. cinerea, respectively, and a gene encoding a DNA-binding protein (DBP) from strawberry......, allowing in situ activity assessment of each fungus in vitro and during their interaction on strawberry leaves. Growth of B. cinerea was inhibited in all pathogen-antagonist interactions while the activity of IK726 was slightly increased. In all in vitro interactions, four of the six genes were upregulated...

  16. Evaluation of potential antagonistism in yeasts, seeking biocontrol of spoilage by Penicillium expansumAvaliação do potencial antagônico de leveduras, visando biocontrole de deterioração por Penicillium expansum

    Directory of Open Access Journals (Sweden)

    Kei-ichi Harada

    2011-12-01

    polpa, produz a patulina, micotoxina teratogênica e cancerígena. Entre as alternativas ao tradicional tratamento químico de doenças pós-colheita de frutos, enfoca-se o biocontrole por leveduras antagonistas, com ênfase em linhagens killer, em função da baixa possibilidade de resíduos tóxicos e com ampla inocuidade demonstrada nos processos fermentativos. O objetivo deste trabalho foi analisar o potencial antagônico de leveduras no controle de P. expansum, mediante antifungigrama em meio sólido e líquido. Do total de 44 leveduras isoladas (16 de frutas, 10 de silagem de milho e 18 de formigueiro de laboratório, 20 apresentaram antagonismo perante esporos de P. expansum em ágar Meio Para Levedura, sendo Debaryomyces hansenii C1 responsável por maior atividade associada à competição por nutrientes (zona de inibição de 31 mm e D. hansenii C7 por antibiose/hiperparasitismo (15 mm. Entretanto, o ensaio realizado com o sobrenadante de cultivo reduziu o número de cepas ativas em cinco, sendo Pichia ohmeri 158 e Candida guilliermondii P3 as de maior atividade antagônica. No antifungigrama em meio líquido (caldo MPL o sobrenadante do cultivo de C. guilliermondii (25ºC/72 horas inibiu 58,15% da germinação dos esporos de P. expansum e P. ohmeri (25ºC/48 horas inibiu o desenvolvimento de hifas em 66,17%. A atividade do meio extracelular baseado em antibiose sugeriu mecanismo associado ao caráter killer, uma vez que ambas as leveduras foram positivas perante as linhagens padrão S. cerevisiae NCYC 1006 e P. kluyveri CAY-15. A diferença entre os sobrenadantes obtidos do cultivo destas leveduras isoladamente e em interação com o fungo teste, visando estímulo adicional na produção de substância antifúngica, não foi significativa (P > 0,05. De acordo com os resultados obtidos, conclui-se que a aplicação de leveduras antagonistas constitui ferramenta promissora no controle biológico de P. expansum em pós-colheita de maçã.

  17. 生防菌解淀粉芽孢杆菌抗菌蛋白的研究进展%Research Advances of Antifungal Proteins Produced by Biocontrol Bacterium,Bacillus amyloliquefaciens

    Institute of Scientific and Technical Information of China (English)

    出晓铭; 林毅雄; 张珅; 严芬; 林河通

    2014-01-01

    Bacillus amyloliquefaciens is a kind of biocontrol bacterium which has great ability against fungi and bacteria,thereby it has high research values and potential for development in biological control of posthar-vest diseases of fruits and vegetables.The separation and purification of antifungal proteins produced by Bacil-lus amyloliquefaciens,the disease resistant mechanisms and the application of biocontrol of antifungal proteins were summarized.The future potential application in biocontrol of postharvest diseases of fruits and vegetables was also discussed.%生防解淀粉芽孢杆菌具有强烈抑制真菌和细菌的能力,在果蔬采后病害防治方面具有巨大的应用潜力。该文对解淀粉芽孢杆菌产生的抗菌蛋白、蛋白的分离纯化、抑菌机理和生防应用等方面进行了综述,并对其在果蔬采后病害防治应用前景进行了展望。

  18. 生防细菌SF-16产芽胞条件的研究%Studies on Biocontrol Bacteria SF-16 Spore Production Condition

    Institute of Scientific and Technical Information of China (English)

    张明; 李欢; 朱莹

    2012-01-01

    生防细菌SF-16为土壤中筛选得到的1株细菌,研究表明,其对多种植物致病真菌有抑制作用。为了提高生防细菌SF-16的芽胞形成率及芽胞数量,以及为工厂化生产生物菌剂提供理论依据,采用摇瓶发酵对芽胞形成的主要影响因素进行了考察。通过单因素实验和正交实验对SF-16菌株产芽胞条件进行了分析,确定了摇瓶发酵最佳条件为:乳糖0.5%、黄豆饼粉2.0%、MnSO4·5H2O0.30%。在该优化条件下,发酵液中颉颃菌的出芽率达到98.3%,最终生物量达到2×109个/mL。%Biocontrol bacteria SF-16 was a selected bacteria strain,research showed that its inhibitory effect on multiple plants.In order to improve biocontrol bacteria SF-16 spore formation rate and quantity,provide theoretical basis for factory production of biological agent,use flask fermentation with a survey on main influencing factors of spore formation.Through single factor experiment and orthogonal experiment,the optimal shaking flask fermentation condition was determined as follow:media composed of 0.5% lactose,2.0% soybean meal,0.30% MnSO4·5H2O.Under this optimum condition,the germination rate achieves 98.3 percentages,Biomass achieves 2×109/mL.

  19. Harlequin, Holberg and the (in)visible masks

    DEFF Research Database (Denmark)

    Holm, Bent

    1998-01-01

    A reading of Holberg's harquinades "Ulysses Von Itacia" and "The Invisibles" placed in a context of European grotesque theatre with a specific regard to the texts relation to respectively older and newer French-Italian masque theatre. The analysis suggeststhat the first text is in perfect...

  20. Characterization and evaluation of Bacillus amyloliquefaciens strain WF02 regarding its biocontrol activities and genetic responses against bacterial wilt in two different resistant tomato cultivars.

    Science.gov (United States)

    Huang, Chu-Ning; Lin, Chan-Pin; Hsieh, Feng-Chia; Lee, Sook-Kuan; Cheng, Kuan-Chen; Liu, Chi-Te

    2016-11-01

    Bacillus amyloliquefaciens strain WF02, isolated from soil collected at Wufeng Mountain, Taiwan, has siderophore-producing ability and in vitro antagonistic activity against bacterial wilt pathogen. To determine the impact of plant genotype on biocontrol effectiveness, we treated soil with this strain before infecting susceptible (L390) and moderately resistant (Micro-Tom) tomato cultivars with Ralstonia solanacearum strain Pss4. We also compared the efficacy of this strain with that of commercial Bacillus subtilis strain Y1336. Strain WF02 provided longer lasting protection against R. solanacearum than did strain Y1336 and controlled the development of wilt in both cultivars. To elucidate the genetic responses in these plants under WF02 treatment, we analyzed the temporal expression of defense-related genes in leaves. The salicylic acid pathway-related genes phenylalanine ammonia-lyase and pathogenesis-related protein 1a were up-regulated in both cultivars, whereas expression of the jasmonic acid pathway-related gene lipoxygenase was only elevated in the susceptible tomato cultivar (L390). These results suggest that WF02 can provide protection against bacterial wilt in tomato cultivars with different levels of disease resistance via direct and indirect modes of action.

  1. Selection of the N-acylhomoserine lactone-degrading bacterium Alteromonas stellipolaris PQQ-42 and of its potential for biocontrol in aquaculture

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    Marta eTorres

    2016-05-01

    Full Text Available The production of virulence factors by many pathogenic microorganisms depends on the intercellular communication system called quorum sensing (QS, which involves the production and release of signal molecules known as autoinducers. Based on this, new-therapeutic strategies have emerged for the treatment of a variety of infections, such as the enzymatic degradation of signalling molecules, known as quorum quenching (QQ. In this study, we present the screening of QQ activity amongst 450 strains isolated from a bivalve hatchery in Granada (Spain, and the selection of the strain PQQ-42, which degrades a wide range of N-acylhomoserine lactones (AHLs. The selected strain, identified as Alteromonas stellipolaris, degraded the accumulation of AHLs and reduced the production of protease and chitinase and swimming motility of a Vibrio species in co-cultivation experiments in vitro. In the bio-control experiment, strain PQQ-42 significantly reduced the pathogenicity of V. mediterranei VibC-Oc-097 upon the coral Oculina patagonica showing a lower degree of tissue damage (29.25±14.63 % in its presence, compared to when the coral was infected with V. mediterranei VibC-Oc-097 alone (77.53±13.22 %. Our results suggest that this AHL-degrading bacterium may have biotechnological applications in aquaculture.

  2. Effects of a non-native biocontrol weevil, Larinus planus, and other emerging threats on populations of the federally threatened Pitcher's thistle, Cirsium pitcheri

    Science.gov (United States)

    Havens, Kayri; Jolls, Claudia L.; Marik, Julie E.; Vitt, Pati; McEachern, A. Kathryn; Kind, Darcy

    2012-01-01

    Larinus planus Frabicius (Curculionidae), is a seed-eating weevil that was inadvertently introduced into the US and was subsequently distributed in the US and Canada for the control of noxious thistle species of rangelands. It has been detected recently in the federally threatened Pitcher's thistle (Cirsium pitcheri). We assayed weevil damage in a natural population of Pitcher's thistle at Whitefish Dunes State Park, Door County, WI and quantified the impact on fecundity. We then estimated the impact of this introduced weevil and other emerging threats on two natural, uninvaded populations of Pitcher's thistle for which we have long-term demographic data for 16 yr (Wilderness State Park, Emmet County, MI) and 23 yr (Miller High Dunes, Indiana Dunes National Lakeshore, Porter County, IN). We used transition matrices to determine growth rates and project the potential effects of weevil damage, inbreeding, goldfinch predation, and vegetative succession on Pitcher's thistle population viability. Based on our models, weevil seed predation reduced population growth rate by 10–12%, but this reduction was enough to reduce time to extinction from 24 yr to 13 yr and 8 yr to 5 yr in the MI and IN population, respectively. This impact is particularly severe, given most populations of Pitcher's thistle throughout its range hover near or below replacement. This is the first report of unanticipated ecological impacts from a biocontrol agent on natural populations of Cirsium pitcheri.

  3. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Maldonado-González, M. Mercedes; Bakker, Peter A. H. M.; Prieto, Pilar; Mercado-Blanco, Jesús

    2015-01-01

    The effective management of Verticillium wilts (VW), diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control VW of olive caused by the highly virulent, defoliating (D) pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V. dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i) olive D and non-defoliating V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii) strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii) strain PICF7 controls VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. A. thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7. PMID:25904904

  4. Colonization process of olive tissues by Verticillium dahliae and its in planta interaction with the biocontrol root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Prieto, Pilar; Navarro‐Raya, Carmen; Valverde‐Corredor, Antonio; Amyotte, Stefan G.; Dobinson, Katherine F.; Mercado‐Blanco, Jesús

    2009-01-01

    Summary The colonization process of Olea europaea by the defoliating pathotype of Verticillium dahliae, and the in planta interaction with the endophytic, biocontrol strain Pseudomonas fluorescens PICF7 were determined. Differential fluorescent protein tagging was used for the simultaneous visualization of P. fluorescens PICF7 and V. dahliae in olive tissues. Olive plants were bacterized with PICF7 and then transferred to V. dahliae‐infested soil. Monitoring olive colonization events by V. dahliae and its interaction with PICF7 was conducted using a non‐gnotobiotic system, confocal laser scanner microscopy and tissue vibratoming sections. A yellow fluorescently tagged V. dahliae derivative (VDAT‐36I) was obtained by Agrobacterium tumefaciens‐mediated transformation. Isolate VDAT‐36I quickly colonized olive root surface, successfully invaded root cortex and vascular tissues via macro‐ and micro‐breakages, and progressed to the aerial parts of the plant through xylem vessel cells. Strain PICF7 used root hairs as preferred penetration site, and once established on/in root tissues, hindered pathogen colonization. For the first time using this approach, the entire colonization process of a woody plant by V. dahliae is reported. Early and localized root surface and root endophytic colonization by P. fluorescens PICF7 is needed to impair full progress of verticillium wilt epidemics in olive. PMID:21255281

  5. Isolation of Stem rot Disease Causing Organism of Brinjal and their in-vitro Inhibition with Fungicides and Bio-control Agents

    Directory of Open Access Journals (Sweden)

    Shaily Javeria

    2014-09-01

    Full Text Available Different strains of Sclerotinia sclerotiorum were isolated from the diseased samples collected from different hosts and locations. Among the 14 isolates, 12 isolates colonies covered the entire Petri plates within 96 hours but, two isolates from fababean and yellow mustard showed slow colony growth within 96 hours. All isolates produced sclerotia which were varied in number, but the fenugreek isolate produced maximum (43 number of sclerotia and lambs quarter isolate produced minimum number of sclerotia (12 on PDA medium. To examine inhibitory effect of fungicide on the mycelial growth of the pathogen, 9 fungicides were tested in vitro against Sclerotinia sclerotiorum, of those carbendazim, carboxin, topsin-M and carbendazim+ mancozeb (SAAF were found most effective and inhibited the mycelial growth of pathogen up to 100 per cent at 0.05%, 0.1%, and 0.2% concentration. The effect of different bioagents viz., Trichoderma harzianum, T. viride, T. koningii, T. atroviride, T. longibraciatum, Aspergillus niger, Chaetomium globosome and Penicillium notatum in inhibiting the growth of Sclerotinia sclerotiorum was studied through “Dual Culture Technique”. The data showed that among the eight biocontrol agent six were fond effective. The maximum inhibition was found by T. harzianum causing 70.82% inhibition of mycelial growth of the pathogen S. sclerotiorum.

  6. Characterization of novel Trichoderma spp. isolates as a search for effective biocontrollers of fungal diseases of economically important crops in Argentina.

    Science.gov (United States)

    Consolo, Verónica Fabiana; Mónaco, Cecilia Inés; Cordo, Cristina Alicia; Salerno, Graciela Lidia

    2012-04-01

    Monoconidial cultures of 33 isolates of Trichoderma from Buenos Aires Province, Argentina were characterized on the basis of twenty eight morphological, physiological and biochemical features. All of them were screened for proteinase, endochitinase and β-1,3 glucanase activity. Universally primed PCR (UP-PCR) and inter-simple sequence repeat (ISSR) techniques were used to examine the genetic variability among isolates, which resulted in 127 bands for the total number of isolates. These results were subjected to numerical analysis revealing 20 haplotypes grouped in five clusters. The ability of Trichoderma isolates to antogonize soil-borne fungal plant pathogens using a dual culture assay was done against five fungal species: Alternaria sp., Bipolaris sorokiniana, Fusarium graminearum, F. solani, and Pyricularia oryzae. The highest inhibition values (85% RI) were obtained against B. sorokiniana and P. oryzae. Three isolates of T. harzianum named as FCCT2, FCCT3 and FCCT9 were capable of causing a high growth inhibition on four of the fungal species assayed, which was in agreement with their higher extracellular hydrolytic activity. Our results suggest that these isolates have the potential to be effective agents for biocontrol of cereal and tomato fungal pathogens.

  7. Effect of organic fertilizers prepared from organic waste materials on the production of antibacterial volatile organic compounds by two biocontrol Bacillus amyloliquefaciens strains.

    Science.gov (United States)

    Raza, Waseem; Wei, Zhong; Ling, Ning; Huang, Qiwei; Shen, Qirong

    2016-06-10

    Three organic fertilizers made of different animal and plant waste materials (BOFs) were evaluated for their effects on the production of antibacterial volatile organic compounds (VOCs) by two Bacillus amyloliquefaciens strains SQR-9 and T-5 against the tomato wilt pathogen Ralstonia solanacearum (RS). Both strains could produce VOCs that inhibited the growth and virulence traits of RS; however, in the presence of BOFs, the production of antibacterial VOCs was significantly increased. The maximum inhibition of growth and virulence traits of RS by VOCs of T-5 and SQR-9 was determined at 1.5% BOF2 and 2% BOF3, respectively. In case of strain T-5, 2-nonanone, nonanal, xylene, benzothiazole, and butylated hydroxy toluene and in case of strain SQR-9, 2-nonanone, nonanal, xylene and 2-undecanone were the main antibacterial VOCs whose production was increased in the presence of BOFs. The results of this study reveal another significance of using organic fertilizers to improve the antagonistic activity of biocontrol agents against phytopathogens.

  8. Winter prevalence of obligate aphid pathogen Pandora neoaphidis mycosis in the host Myzus persicae populations in southern China: modeling description and biocontrol implication

    Directory of Open Access Journals (Sweden)

    Xiang Zhou

    2012-03-01

    Full Text Available Pandora neoaphidis overwintering had been investigated by monitoring its prevalence in Myzus persicae populations in open fields. Cabbage plants in field plots were weekly taken after mycosis initiation, to count and examine the living and dead aphids infected by P. neoaphidis. Based on the field data, infection levels (I varied with field temperature (T, relative humidity (RH and aphid count (numbers of living aphids per plant, N over days (D, fitting well to the modified logistic equation I=0.91/[1+exp(8.5+(2.0H T H RH-20.2NI0D] (r²=0.897, where H T indicated daily hours of low temperature (90% RH and I0 primary infection level. The model demonstrated the abiotic and biotic factors influencing P. neoaphidis mycosis development in winter, and also verifies the fungal overwintering by infecting available host aphids without a resting stage. Ultimately, P. neoaphidis mycosis reduced 81.4% of aphid populations, presenting great potential for biocontrol.

  9. Potential of Burkholderia seminalis TC3.4.2R3 as Biocontrol Agent Against Fusarium oxysporum Evaluated by Mass Spectrometry Imaging

    Science.gov (United States)

    Araújo, Francisca Diana da Silva; Araújo, Welington Luiz; Eberlin, Marcos Nogueira

    2017-02-01

    Species of genus Burkholderia display different interaction profiles in the environment, causing either several diseases in plants and animals or being beneficial to some plants, promoting their growth, and suppressing phytopathogens. Burkholderia spp. also produce many types of biomolecules with antimicrobial activity, which may be commercially used to protect crops of economic interest, mainly against fungal diseases. Herein we have applied matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to investigate secondary metabolites produced by B. seminalis TC3.4.2R3 in monoculture and coculture with plant pathogen Fusarium oxysporum. The siderophore pyochelin and the rhamnolipid Rha-Rha-C15-C14 were detected in wild-type B. seminalis strain, and their productions were found to vary in mutant strains carrying disruptions in gene clusters associated with antimicrobial compounds. Two mycotoxins were detected in F. oxysporum. During coculture with B. seminalis, metabolites probably related to defense mechanisms of these microorganisms were observed in the interspecies interaction zone. Our findings demonstrate the effective application of MALDI-MSI in the detection of bioactive molecules involved in the defense mechanism of B. seminalis, and these findings suggest the potential use of this bacterium in the biocontrol of plant diseases caused by F. oxysporum.

  10. Biocontrol of Rhizoctonia solani damping-off and promotion of tomato plant growth by endophytic actinomycetes isolated from native plants of Algerian Sahara.

    Science.gov (United States)

    Goudjal, Yacine; Toumatia, Omrane; Yekkour, Amine; Sabaou, Nasserdine; Mathieu, Florence; Zitouni, Abdelghani

    2014-01-20

    Thirty-four endophytic actinomycetes were isolated from the roots of native plants of the Algerian Sahara. Morphological and chemical studies showed that twenty-nine isolates belonged to the Streptomyces genus and five were non-Streptomyces. All isolates were screened for their in vitro antifungal activity against Rhizoctonia solani. The six that had the greatest pathogen inhibitory capacities were subsequently tested for their in vivo biocontrol potential on R. solani damping-off in sterilized and non-sterilized soils, and for their plant-growth promoting activities on tomato seedlings. In both soils, coating tomato seeds with antagonistic isolates significantly reduced (P<0.05) the severity of damping-off of tomato seedlings. Among the isolates tested, the strains CA-2 and AA-2 exhibited the same disease incidence reduction as thioperoxydicarbonic diamide, tetramethylthiram (TMTD) and no significant differences (P<0.05) were observed. Furthermore, they resulted in a significant increase in the seedling fresh weight, the seedling length and the root length of the seed-treated seedlings compared to the control. The taxonomic position based on 16S rDNA sequence analysis and phylogenetic studies indicated that the strains CA-2 and AA-2 were related to Streptomyces mutabilis NBRC 12800(T) (100% of similarity) and Streptomyces cyaneofuscatus JCM 4364(T) (100% of similarity), respectively.

  11. Biological studies on the snail intermediate hosts of schistosomiasis with a special emphasis on using larval echinostomes as biocontrol agent against larval schistosomes and snails.

    Science.gov (United States)

    Rashed, A A

    2002-12-01

    The present investigation deals with the infectivity of the two snail intermediate hosts of schistosomiasis, Biomphalaria alexandrina and Bulinus truncatus collected from nine drains in Sharkia Governorate, Egypt. The rate of infection among the snails was general low being 0% in many drains. Regarding B. alexandrina, the rate of infection ranged from 4-16%, and in B. truncatus ranged from 4-8%. Infection with larval echinostomes was dominant over larval schistosomes in the two snail vectors. The distribution of larval schistosomes was restricted to the hepatopancreas of the two snail vectors, while larval echinostomes were distributed in head, foot, kidney, haemocoelic cavity, hepatopancreas...etc. The predation of larval schistosomes by larval echinostomes and the severe histopathological effects induced by larval ecbinostomes strongly enhances using them as biocontrol agent. The physico-chemical parameters and pollution condition in the drains seem to have no effect on the process of snails infectivity. It is concluded that larval echinostomes can resist the polluting conditions in the drain. The two snail vectors exhibit very minimal or rare host response against larval echinostomes. Probably, the toxicants and pollutants in the drain may act as stressor that makes the snails much more susceptible to infection by larval trematodes.

  12. Evaluación de microorganismos con potencial de promoción de crecimiento vegetal y biocontrol de Spongospora subterranea

    Directory of Open Access Journals (Sweden)

    Juliana Soler Arango

    2012-04-01

    Full Text Available Normal 0 21 false false false ES-CO X-NONE X-NONE MicrosoftInternetExplorer4 Título en ingles: Evaluation of microorganisms  with potential  for plant  growth  promotion and biological control of    Spongospora subterranea Resumen: La sarna polvosa de la papa es causada por el patógeno Spongospora subterranea, que disminuye la calidad y producción de tubérculos y facilita la entrada de otros patógenos. Esta enfermedad afecta las principales zonas productoras del mundo, debido a la falta de tratamientos efectivos contra el patógeno y al comercio de tubérculos-semilla infectados. Algunas investigaciones indican que los agentes biocontroladores podrían contribuir a reducir la actividad de S. subterranea a través de efectos sobre la viabilidad de sus quistosoros o mediante efectos estimulantes del crecimiento de la planta. En este estudio se emplearon bacterias aisladas del interior de raíz, rizósfera y superficie de tubérculos de un cultivo de papa (Solanum tuberosum variedad Diacol Capiro y seleccionadas por su capacidad para producir indoles totales y quitinasas. En estudios paralelos se determinó su capacidad para promover la velocidad de germinación en brotes de tubérculos o para controlar  S. subterranea en raíces y promover el crecimiento vegetal de plántulas en invernadero. La mayoria de los aislamientos evaluados incrementraron la longitud de brotes de tubérculos en el laboratorio. En el invernadero, en suelo no estéril y en presencia del patógeno, se encontró que 2 de los 10 aislamientos seleccionados por su capacidad para producir indoles totales y quitinasas, presentaron promoción de crecimiento vegetal y posible biocontrol del patógeno. Estos resultados sugieren un gran potencial para la selección de microorganismos biocontroladores y desarrollo de bioproductos a partir de recursos microbiológicos locales. Palabras clave: sarna polvosa de la papa; indoles totales; quitinasas; control biológico. Abstract

  13. Partial purification, characterization, and kinetic studies of a low-molecular-weight, alkali-tolerant chitinase enzyme from Bacillus subtilis JN032305, A potential biocontrol strain.

    Science.gov (United States)

    Shivakumar, Srividya; Karmali, Anika Nayak; Ruhimbana, Charles

    2014-01-01

    A new alkalophilic low-molecular-mass chitinase of 14 kD from the potent biocontrol agent Bacillus subtilis JN032305 was partially purified and enzymology of the chitinase was studied. The enzyme showed optimal pH of 9.0 and temperature of 50°C. The enzyme was found stable during the 60-min incubation at 50 °C. The chitinase was inhibited by group specific agents like IAA, DAN, TLCK, and SDS and metal ions Mg(2+), Ca(2+), Fe(2+), Mn(2+), Ba(2+), and Hg(2+), whereas Zn(2+) did not show significant inhibitory effect against the chitinase. PMSF partially inhibited the enzyme. Substrates specificity tests indicated that the enzyme showed 75% of relative activity on glycol chitin, 58% on carboxymethylcellulose (CMC), 33% on chitin flakes, and 166% laminarin compared to that on colloidal chitin. The enzyme also hydrolyzed 4-methylumbelliferyl-N-acetyl-D-glucosaminide, indicating its chitobiase activity. The chitinase of this study has broad specificity, which could hydrolyze not only the glycosidic bond in GlcNAc-GlcNAc but also that of related carbohydrates with glycosidic linkages. The partially purified chitinase not only showed antifungal activity against Rhizoctonia solani and Colletotrichum gloeosporioides, two potent phytopathogens of chilli, but also increased the germination of chilli seeds when infected with the two potent phytopathogenic fungi.

  14. Genomic and metabolic traits endow Bacillus velezensis CC09 with a potential biocontrol agent in control of wheat powdery mildew disease.

    Science.gov (United States)

    Cai, Xun-Chao; Liu, Chang-Hong; Wang, Bao-Tong; Xue, Ya-Rong

    2017-03-01

    Bacillus velezensis CC09, which was isolated from healthy leaves of Cinnamomum camphora and previously identified as Bacillus amyloliquefaciens CC09, shows great potential as a new biocontrol agent, in control of many phytopathogenic diseases. To extend our understanding of the potential antifungal capacities, we did a whole genome analysis of strain CC09. Result shows that strain CC09 has a relatively large genome size (4.17Mb) with an average GC content of 46.1%, and 4021 predicted genes. Thirteen secondary metabolites encoding clusters have been identified within the genome of B. velezensis CC09 using genome mining technique. Data of comparative genomic analysis indicated that 3 of the clusters are conserved by all strains of B. velezensis, B. amyloliquefaciens and B. subtilis 168, 9 by B. velezensis and B. amyloliquefaciens, and 2 by all strains of B. velezensis. Another 2 clusters encoding NRPS (Non-Ribosomal Peptide Synthetases) and NRPS-TransATPKS (NRPS and trans-Acyl Transferase Polyketide Synthetases) respectively are observed only in 15 B. velezensis strains, which might lead to the synthesis of novel bioactive compounds and could be explored as antimicrobial agents in the future. These clusters endow B. velezensis CC09 with strong and broad antimicrobial activities, for example, in control of wheat powdery mildew disease. Moreover, our data further confirmed the taxonomy of strain CC09 is a member of B. velezensis rather than a strain of B. amyloliquefaciens based on core genome sequence analysis using phylogenomic approach.

  15. Secretome of the biocontrol agent metarhizium anisopliae induced by the cuticle of the cotton pest Dysdercus peruvianus reveals new insights into infection.

    Science.gov (United States)

    Beys-da-Silva, Walter O; Santi, Lucélia; Berger, Markus; Calzolari, Diego; Passos, Dario O; Guimarães, Jorge A; Moresco, James J; Yates, John R

    2014-05-02

    Metarhizium anisopliae is an entomopathogenic fungus that has evolved specialized strategies to infect insect hosts. Here we analyzed secreted proteins related to Dysdercus peruvianus infection. Using shotgun proteomics, abundance changes in 71 proteins were identified after exposure to host cuticle. Among these proteins were classical fungal effectors secreted by pathogens to degrade physical barriers and alter host physiology. These include lipolytic enzymes, Pr1A, B, C, I, and J proteases, ROS-related proteins, oxidorreductases, and signaling proteins. Protein interaction networks were generated postulating interesting candidates for further studies, including Pr1C, based on possible functional interactions. On the basis of these results, we propose that M. anisopliae is degrading host components and actively secreting proteins to manage the physiology of the host. Interestingly, the secretion of these factors occurs in the absence of a host response. The findings presented here are an important step in understanding the host-pathogen interaction and developing more efficient biocontrol of D. peruvianus by M. anisopliae.

  16. Biocontrol traits and antagonistic potential of Bacillus amyloliquefaciens strain NJZJSB3 against Sclerotinia sclerotiorum, a causal agent of canola stem rot.

    Science.gov (United States)

    Wu, Yuncheng; Yuan, Jun; Raza, Waseem; Shen, Qirong; Huang, Qiwei

    2014-10-01

    Bacillus amyloliquefaciens strain NJZJSB3 has shown antagonism of several phytopathogens in vitro, especially Sclerotinia sclerotiorum. Both the broth culture and cell suspension of strain NJZJSB3 could completely protect the detached leaves of canola (Brassica napus) from S. sclerotiorum infection. In pot experiments, the application of strain NJZJSB3 cell suspension (10(8) CFU/ml) decreased the disease incidence by 83.3%, a result similar to commercially available fungicide (Dimetachlone). In order to investigate the potential biocontrol mechanisms of strain NJZJSB3, the nonvolatile antifungal compounds it produces were identified as iturin homologs using HPLC-ESI-MS. Antifungal volatile organic compounds were identified by gas chromatography-mass spectrometry. The detected volatiles toluene, phenol, and benzothiazole showed antifungal effects against S. sclerotiorum in chemical control experiments. Strain NJZJSB3 also produced biofilm, siderophores and cell-wall-degrading enzymes (protease and β-1,3-glucanase). These results suggest that strain NJZJSB3 can be a tremendous potential agent for the biological control of sclerotinia stem rot.

  17. Differential Expression of Malate Dehydrogenase and Isocitrate Dehydrogenase in Diapaused Ladybird, Coccinella septempunctata L%苹果酸脱氢酶与异柠檬酸脱氢酶在滞育七星瓢虫中的差异表达

    Institute of Scientific and Technical Information of China (English)

    刘遥; 张礼生; 陈红印; 黄凤霞; 蒋莎; 任小云

    2014-01-01

    To analyze the categories and functions of the diapause related proteins in ladybird, Coccinella septempunctata, proteomics methods, such as two-dimensional electrophoresis, ESI-QUAD-TOF and bioinformatics, were used to identify the proteins with more than 2 folds of expression quantity. Mascot database search determined two matching proteins which showed different expression and are associated with the Krebs cycle, malate dehydrogenase (gi|212508346) and isocitrate dehydrogenase (gi|21392222), which were up-regulated and down-regulated, respectively. We analyzed the possible reasons and provided a theoretical basis for the diapauses environmental regulation at the protein level.%为分析七星瓢虫滞育相关蛋白质的类别和功能,在滞育调控及滞育后生物学研究的基础上,应用双向电泳、质谱分析(ESI-QUAD-TOF)、生物信息学等蛋白质组学方法,对表达量存在2倍及以上差异且差异显著的蛋白点进行鉴定。应用 Mascot 软件进行数据库检索,根据数据的匹配程度鉴定蛋白质。所得蛋白质中,参与三羧酸循环的两种关键酶呈现差异性表达,其中苹果酸脱氢酶(gi|212508346)呈上调表达,异柠檬酸脱氢酶(gi|21392222)则呈下调表达。苹果酸脱氢酶的增加,推测与滞育状态下的生理需求相关:一方面与昆虫对 NAD 的合成和利用有关,另一方面或是七星瓢虫应对滞育环境条件的一种应激方式,与正常个体的代谢通路相比,滞育个体开启了另外的代谢通路以适应环境条件的改变。异柠檬酸脱氢酶作为三羧酸循环中起关键调节作用的限速酶,在滞育个体中下调表达,或反映了三羧酸循环整体速率的降低,表现在滞育七星瓢虫体内维持了低水平的能量代谢。本文的研究结果,为从蛋白质水平深入揭示七星瓢虫滞育调控及其机理提供一定的参考。

  18. 木霉菌生物防治作用机理与应用研究进展%Progress on Mechanism and Applications of Trichoderma as a Biocontrol Microbe

    Institute of Scientific and Technical Information of China (English)

    陈捷; 朱洁伟; 张婷; 王秉丽

    2011-01-01

    Trichoderma is widely used as a biocontrol microbe against plant diseases in the world, which is mainly applied for controlling a variety of soil bome plant diseases and some plant aboveground diseases. With the advent of MAMPs (microbe-associated molecular patterns) theory, the study on mechanism of plant disease control and improved plant resistance to stress factors with Trichoderma as a biocontrol agent has come into a new stage, especially as the development of technologies based on systems biology, it has become possible to understand the nature of interaction of plant- Trichoderma -pathogen from point of "omics" view, which therefore would intensively enrich the theory basis of Trichoderma as biocontrol agent. Meanwhile, a diversified technical system for applying Trichoderma products developed in national agricultural industry would provide great promotion to sustainable development of agriculture in the future. This review will focus on new research progress on biocontrol mechanism with Trichoderma against plant diseases at molecular level.%木霉菌Trichoderma是国际上应用非常普遍的生防真菌.随着植物免疫的MAMPs(微生物互作分子模式)理论的发展,利用木霉菌防治病害和提高作物抗逆性机理研究进入了一个新阶段,尤其是系统生物学方法的应用,使得人们在"组学"尺度上认识木霉菌与植物和病原菌互作的本质成为可能,这将极大丰富木霉菌生物防治植物病害的理论基础.在我国建立木霉菌多样化应用技术途径是发挥木霉菌在农业可持续发展中作用的重要发展方向.本文重点介绍木霉菌生物防治分子机理研究的新进展.

  19. Biocontrol Efficacy of Three Antagonistic Yeasts Against Penicillium expansum in Harvested Apple Fruits%三种拮抗酵母菌对苹果采后青霉病的抑制效果

    Institute of Scientific and Technical Information of China (English)

    秦国政; 田世平; 刘海波; 徐勇

    2003-01-01

    从苹果果实上分离获得的50余种酵母菌中筛选出了能够有效地抑制苹果青霉病(Penicilium expansum Link)的丝孢酵母(Trichosporon pullulans (Lindner.) Diddens and Lodder)、罗伦隐球酵母(Cryptococcus laurentii (Kuffer.) Skinner)和粘红酵母(Rhodotorula glutinis (Fresen.) F. C. Harrison).其中,抑病效果最好的T. pullulans 是一种用于采后果实生物防治的新型拮抗菌.研究了这三种拮抗菌不同浓度处理和外加营养物质以及与钙配合使用对苹果青霉病的抑病效果.实验结果表明:酵母菌浓度越高,抑病作用越强;外源营养物质的加入削弱了酵母菌的拮抗效果;在C. laurentii的细胞悬浮液中加入0.18 mol/L 的CaCl2能显著提高其抑病能力,但增加CaCl2 对T. pullulans 和R. glutinis 的抑病效果却没有明显作用.%Three antagonistic yeasts, Trichosporon pullulans (Lindner.) Diddens and Lodder, Cryptococcus laurentii (Kuffer.) Skinner and Rhodotorula glutinis (Fresen.) F. C. Harrison, selected from over 50 yeasts on apple fruits, were investigated of their biocontrol efficacy against blue mould rot caused by Penicillium expansum Link in apple fruits. T. pullulans was identified to be a new yeast antagonist and was the most effective at inhibiting blue mould rot in the three yeasts. The effects of different concentrations of the three yeasts and addition of nutrients, as well as combination with calcium on controlling blue mould rot in apples were presented in the paper. The results indicated that the higher the yeast concentrations, the more effective the yeasts on biocontrol activity. Addition of nutrients reduced the biocontrol capacity of the yeasts. Combination of 0.18 mol/L CaCl2 with C. laurentii cell suspensions could significantly enhance its effect to P. expansum in apple fruits, while the efficacy of calcium on biocontrol activity of T. pullulans or R. glutinis was not remarkable.

  20. The potential for biocontrol in stored products in general, with specific attention to application of parasitoids against Sitophilus granarius in grains stores at low temperatures

    DEFF Research Database (Denmark)

    Hansen, Lise Stengård

    : This presentation will give an overview of the current state of biocontrol in stored products. An EU-funded COST Action Working Group, active during 2000-2006. evaluated the possibilities in different sectors: grain stores, mills and bakeries, pasta factories, stored nuts and dried fruit, etc. Three situations were...... identified with the greatest potential for widespread application: (1) empty room treatment against mites, beetles and moths, (2) treatment of bulk commodities against Sitophilus spp. and mites, and (3) application of egg-parasitoids against moths in packaged products. As an example, results of research...

  1. 黄曲霉毒素生物防控菌的筛选及鉴定%Screening and Identification of Aflatoxin Bio-Controlling Bacterial Strain

    Institute of Scientific and Technical Information of China (English)

    宫小明; 马荣桧; 孙军; 张艺兵; 于金玲; 丁葵英; 郭礼强

    2015-01-01

    Aflatoxin bio-controlling bacterial strain was screened in order to provide support for controlling aflatoxin. The growth,sporogenesis,and aflatoxin degradable experiments were carried out to the needed and inhibition strains screened from soil collected in peanut source land adopting Oxford-cup method. Two aflatoxin bio-controlling bacterial strains were screened and numbered as 21-1-2 and 17-3,they were characterized by authorized institution,the inhibi-tion strain 21-1-2 to be Bacillus subtilis,and inhibition strain 17-3 to be Bacillus licheniformis. They were studied on several aspects including the inhibition against the germination of Aspergillus spores,the inhibition against the growth of A. flavus,the extension of their mycelia,and the reduction of the aflatoxin production,and the degradation effects of aflatoxin. The results showed that the inhibition strains could significantly inhibit the spore germination of toxin-pro-ducing Aspergillus strains,their growth,and the extension of their mycelia,reduce the production of aflatoxin,as well as the degradation of aflatoxin.%筛选黄曲霉毒素生物防控菌,为黄曲霉毒素的生物防控提供支持。以花生原产地土壤为材料,采用牛津杯法筛选所需菌株。对筛选出的拮抗菌株进行抑制产毒曲霉菌株的生长、产孢、降解黄曲霉毒素实验。筛选出2株黄曲霉毒素生防细菌,编号21-1-2、17-3,经鉴定,拮抗菌21-1-2为枯草芽胞杆菌,拮抗菌17-3为地衣芽胞杆菌。分别对拮抗菌对曲霉孢子萌发的抑制、抑制黄曲霉的生长和菌丝延长以及减少黄曲霉毒素的产生、对黄曲霉毒素的分解作用等几个方面进行研究,结果表明,拮抗菌可以明显抑制产毒曲霉孢子的萌发、生长、菌丝的延长,减少黄曲霉毒素的产生以及分解黄曲霉毒素。

  2. Suppression of the biocontrol agent trichoderma harzianum by mycelium of the arbuscular mycorrhizal fungus glomus intraradices in root-free soil

    Science.gov (United States)

    Green; Larsen; Olsson; Jensen; Jakobsen

    1999-04-01

    Trichoderma harzianum is an effective biocontrol agent against several fungal soilborne plant pathogens. However, possible adverse effects of this fungus on arbuscular mycorrhizal fungi might be a drawback in its use in plant protection. The objective of the present work was to examine the interaction between Glomus intraradices and T. harzianum in soil. The use of a compartmented growth system with root-free soil compartments enabled us to study fungal interactions without the interfering effects of roots. Growth of the fungi was monitored by measuring hyphal length and population densities, while specific fatty acid signatures were used as indicators of living fungal biomass. Hyphal 33P transport and beta-glucuronidase (GUS) activity were used to monitor activity of G. intraradices and a GUS-transformed strain of T. harzianum, respectively. As growth and metabolism of T. harzianum are requirements for antagonism, the impact of wheat bran, added as an organic nutrient source for T. harzianum, was investigated. The presence of T. harzianum in root-free soil reduced root colonization by G. intraradices. The external hyphal length density of G. intraradices was reduced by the presence of T. harzianum in combination with wheat bran, but the living hyphal biomass, measured as the content of a membrane fatty acid, was not reduced. Hyphal 33P transport by G. intraradices also was not affected by T. harzianum. This suggests that T. harzianum exploited the dead mycelium but not the living biomass of G. intraradices. The presence of external mycelium of G. intraradices suppressed T. harzianum population development and GUS activity. Stimulation of the hyphal biomass of G. intraradices by organic amendment suggests that nutrient competition is a likely means of interaction. In conclusion, it seemed that growth of and phosphorus uptake by the external mycelium of G. intraradices were not affected by the antagonistic fungus T. harzianum; in contrast, T. harzianum was adversely

  3. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Directory of Open Access Journals (Sweden)

    M. Mercedes eMaldonado-González

    2015-04-01

    Full Text Available The effective management of Verticillium wilts, diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control Verticillium wilt of olive caused by the highly-virulent, defoliating (D pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V.dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i olive D and non-defoliating (ND V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii strain PICF7 controls Verticillium wilt (VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. Arabidopsis thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7.

  4. Identification of Biocontrol Bacteria against Soybean Root Rot with Biolog Automatic Microbiology Analysis System%拮抗大豆根腐病细菌的Biolog鉴定

    Institute of Scientific and Technical Information of China (English)

    许艳丽; 刘海龙; 李春杰; 潘凤娟; 李淑娴; 刘新晶

    2012-01-01

    In order to identify the systematic position of taxonomy of two biocontrol bacteria against soybean root rot. Traditional morphological identification and BIOLOG automatic microbiology analysis system were used to identify strain B021a and B04b. The results showed that similarity value of strain B021a with Vibrio tubiashii was 0. 634, possibility to 86% and genetic distance to 4.00,and similarity value of strain B04b with Pasteurella trehalosi was 0. 610,probability to 75% and genetic distance to 2. 77. Strain B021a was identified as Vibrio tubiashii and strain B04b as Pasteurella trehalosi by colony morphological propertie and BIOLOC analysis system.%为明确2株生防细菌的分类地位,采用传统形态学方法结合Biolog微生物自动分析系统,鉴定了大豆根腐病的2株生防细菌.结果表明,菌株B021a与塔式弧菌相似度值为0.634,可能性是86%,遗传距离为4.00.菌株B04b与海藻巴斯德菌相似度值为0.610,可能性是75%,遗传距离为2.77.综合形态学和Biolog鉴定结果,认为菌株B021a是塔式弧菌,菌株B04b是海藻巴斯德菌.

  5. The use of annual killifish in the biocontrol of the aquatic stages of mosquitoes in temporary bodies of fresh water; a potential new tool in vector control

    Directory of Open Access Journals (Sweden)

    Adrias Araceli Q

    2010-05-01

    Full Text Available Abstract Background Mosquitoes that breed in temporary pools in remote areas that dry up seasonally are especially difficult to control through chemical or biological means. The annual killifish has been suggested as a means of eradicating the aquatic stages of mosquitoes in transient pools because they can maintain permanent populations in such habitats by undergoing suspended animation or diapause during the embryonic stages to survive periodic drought. However, very little is known about the predatory activity of annual killifish and their usefulness in mosquito control. Results The annual killifish, Nothobranchius guentheri, native to Tanzania, was used in this investigation. Food preference was tested under laboratory conditions by feeding juvenile killifish with 2nd instar mosquito larvae of Culex quinquefasciatus in the presence of alternative food sources, such as rotifers and chironomid larvae. Semi-field tests were conducted by introduction of hibernating killifish embryos and juvenile fish to artificial ponds in an outdoor open environment that allowed natural oviposition of Cx. quinquefasciatus. Food preference studies show that N. guentheri preferred to prey on mosquito larvae than either chironomid or rotifers. When hibernating killifish embryos were added to ponds simultaneously with the addition of freshwater, the embryos hatched and fed on mosquito larval population resulting in complete elimination of the immature stages. The introduction of juvenile fish to ponds with high density of mosquito larvae resulted in total eradication of the mosquito population due to predation by fish. Complete biocontrol of the mosquito larval population was achieved in the presence of 3 fish per m2 of pond surface area. Conclusions The annual killifish provides yet another tool that may be employed in the eradication diseases carried by mosquitoes through vector control, particularly in temporary bodies of freshwater. The fish can be conveniently

  6. Investigating the compatibility of the biocontrol agent Clonostachys rosea IK726 with prodigiosin-producing Serratia rubidaea S55 and phenazine-producing Pseudomonas chlororaphis ToZa7.

    Science.gov (United States)

    Kamou, Nathalie N; Dubey, Mukesh; Tzelepis, Georgios; Menexes, Georgios; Papadakis, Emmanouil N; Karlsson, Magnus; Lagopodi, Anastasia L; Jensen, Dan Funck

    2016-05-01

    This study was carried out to assess the compatibility of the biocontrol fungus Clonostachys rosea IK726 with the phenazine-producing Pseudomonas chlororaphis ToZa7 or with the prodigiosin-producing Serratia rubidaea S55 against Fusarium oxysporum f. sp. radicis-lycopersici. The pathogen was inhibited by both strains in vitro, whereas C. rosea displayed high tolerance to S. rubidaea but not to P. chlororaphis. We hypothesized that this could be attributed to the ATP-binding cassette (ABC) proteins. The results of the reverse transcription quantitative PCR showed an induction of seven genes (abcB1, abcB20, abcB26, abcC12, abcC12, abcG8 and abcG25) from subfamilies B, C and G. In planta experiments showed a significant reduction in foot and root rot on tomato plants inoculated with C. rosea and P. chlororaphis. This study demonstrates the potential for combining different biocontrol agents and suggests an involvement of ABC transporters in secondary metabolite tolerance in C. rosea.

  7. Biocontrol of collar rot disease of betelvine (Piper betle L.) caused by Sclerotium rolfsii by using rhizosphere-competent Pseudomonas fluorescens NBRI-N6 and P. fluorescens NBRI-N.

    Science.gov (United States)

    Singh, Anand; Mehta, Sangeeta; Singh, Harikesh Bahadur; Nautiyal, Chandra Shekhar

    2003-08-01

    Collar rot disease of betelvine (Piper betle L.) caused by Sclerotium rolfsii is difficult to control by conventional means by use of chemicals; therefore, use of biocontrol agents is desirable. In the present study, 186 bacterial strains of different morphological types were screened for their biocontrol activity against S. rolfsii under in vitro conditions. Two strains, Pseudomonas fluorescens NBRI-N6 and P. fluorescens NBRI-N, were selected for further studies because of their ability to inhibit the mycelial growth of the pathogen significantly. Spontaneous rifampicin-resistant (Rif) derivatives of P. fluorescens NBRI-N6 and P. fluorescens NBRI-N showing growth rate and membrane protein composition comparable to the wild type were selected to facilitate their monitoring in the rhizosphere. Field trials demonstrated that strain P. fluorescens NBRI-N6 was better than P. fluorescens NBRI-N in increasing the yield of betelvine significantly, whereas a consortium of the two strains controlled the disease more than either of the strains. The screening method should prove useful in identifying rhizosphere bacteria with the greatest potential for controlling diseases caused by phytopathogenic fungi.

  8. 枯草芽孢杆菌生防菌产孢条件的优化%Optimization on Sporulation Conditions of Biocontrol Bacteria Bacillus subtilis

    Institute of Scientific and Technical Information of China (English)

    李忠; 乐峰松; 殷红福; 刘华玉

    2013-01-01

    [Objective] The aim was to explore the optimal sporulation conditions of biocontrol bacteria Bacillus subtilis. [Method] The fermentation medium and conditions of Bacillus subtilis were optimized by using single factor experiment and orthogonal experimental design. [ Result ] The optimal fermentation medium was as followed; 1.500% glucose, 1.000% starch, 1.500% peanut cake,0.005% MnSO4 · H2O,0.050% Mg-SO4,0.150% KH2PO4,0.300% K2HPO4 · 3H2O and 0.050% CaCO3. The optimal fermentation conditions were as followed: culture transferring time 18 -20 h,temperature 37 ℃,initial pH 7.5 .rotational speed 250 r/min,volume of inoculation 10%. [ Conclusion] The research result provides reference for improving the yield of Bacillus subtilis and decreasing production cost.%[目的]探讨枯草芽孢杆菌生防菌的最优产孢条件.[方法]通过单因素试验及正交试验设计对枯草芽孢杆菌发酵培养基和发酵条件进行了优化.[结果]枯草芽孢杆菌的优化培养基为:葡萄糖1.500%,淀粉1.000%,花生饼1.500%,MnSO4·H2O 0.005%,无水MgSO40.050%,KH2PO40.150%,K2HPO4·3H2O 0.300%,CaCO30.050%;最适培养条件为:最佳移种时间18~20 h,温度37℃,pH7.5,转速250 r/min,接种量10%.[结论]为提高枯草芽孢杆菌的芽孢产量及降低生产成本提供了参考.

  9. The Biocontrol Effects of Pseudomonas in the Rhizosphere of Tomatoes%番茄根际促生菌-假单胞菌的生防作用

    Institute of Scientific and Technical Information of China (English)

    岳东霞; 张要武

    2009-01-01

    The colonization and biocontrol effects of plant growth promoting rhizobacteria-Pseudomonads in the rhizo-sphere of tomatoes were investigated. Pseudomonas CBT1 can colonize the rhizosphere of cucumbers by the methods of seed soaking and root watering. The antimicrobial activity results showed that some isolates suppressed the mycelial growth of B. cinerea and F. oxysporum f. sp. cucumerinum, the highest inhibitory rate was 89.1% and 65.6% ,respectively. The efficient isolates were tested and found relative control effects on grey mold and fusarium wilt diseases of cucumber were 44.0% -67.7% and 47.7% -55.4% in pot experiments,respectively.%研究了番茄根际促生菌--假单胞菌在黄瓜根部的定殖能力以及对黄瓜灰霉病和枯萎病的生防作用.结果表明,假单胞菌在浸种和灌根两种情况下均能够定殖在黄瓜根部.拮抗测定表明,一些株系对黄瓜灰霉病菌和黄瓜枯萎病菌有较好的抑制作用,最高抑制率分别达到89.1%和65.6%.离体及盆栽试验表明,CBT1、CBT3、CBT6对黄瓜灰霉病有较好的防治效果,相对防效分别为51.1%~62.4%和44.0%~67.7%;CBT1、CBT6、CBT7对黄瓜枯萎病有一定的防治效果,相对防效分别为55.3%~59.3%和47.7%~55.4%.

  10. 硬蜱生防真菌制剂的研究及应用%Fungal bio-control agents against Ixodid tick——A review

    Institute of Scientific and Technical Information of China (English)

    孙明; 王晓燕; 罗建勋

    2012-01-01

    Entomopathogenic fungi as potential agents for bio-control have been widely applied in the control of insect pests in agriculture.However, the application remains in laboratory scale for the control of ectoparasites.Owing to the need to combat the short lasting period of chemical acaricides and reduction of pollution, it is urgent to develop sufficient, stable and safe measures for tick control.We reviewed the primary scientific achievements in utilization of environmental microbes for controlling of ticks.Studies conducted in this field may benefit to sustainable development, environmental protection, maintaining ecological balance and production of green products.%昆虫病原真菌作为一种很有潜力的生物控制因子,已在农业害虫生物防治领域得到广泛的应用,而在兽医外寄生虫病防治的研究才刚刚起步.针对目前用于蜱化学药物防治的药效持久期短的技术难点,建立和改进蜱虫的防治体系,降低环境污染,减少或禁用化学农药势在必行,开发高效、稳定的生物农药已成为当务之急.作者等结合蜱生物防治的初步研究成果,特别是针对栖息土壤环境中的昆虫病原微生物对蜱的致病力筛选及其生防制剂进行探讨,以促进这一研究领域的可持续发展,这对于保护环境、维持生态平衡、发展无污染的绿色畜牧业产品以及对畜牧业的可持续发展具有极为重要的意义.

  11. Environmental distribution and genetic diversity of vegetative compatibility groups determine biocontrol strategies to mitigate aflatoxin contamination of maize by Aspergillus flavus.

    Science.gov (United States)

    Atehnkeng, Joseph; Donner, Matthias; Ojiambo, Peter S; Ikotun, Babatunde; Augusto, Joao; Cotty, Peter J; Bandyopadhyay, Ranajit

    2016-01-01

    > 400 km away. The present study identified widely distributed VCGs in Nigeria such as AV0222, AV3279, AV3304 and AV16127, whose atoxigenic members can be deployed for a region-wide biocontrol of toxigenic isolates to reduce aflatoxin contamination in maize.

  12. 植物内生细菌及其生防作用研究进展%Endophytic bacteria:research advances and biocontrol applications

    Institute of Scientific and Technical Information of China (English)

    何玲敏; 叶建仁

    2014-01-01

    植物内生细菌定殖于健康植物体内,与寄主植物在长期进化过程中形成了和谐联合关系,对寄主植物具有防病、促生、固氮和生物修复等生物学作用,目前已被广泛应用于植物病害的生物防治。近年来,通过基因工程手段对植物内生细菌进行基因改造,增强了内生细菌的生防潜能和综合防治效果。笔者从植物内生细菌的概念、分类鉴定方法、与寄主植物的互作等方面概述了植物内生细菌的国内外研究成果,并着重探讨了内生细菌的植物修复能力和内生细菌在农林业病虫害防治上的应用潜力以及存在的问题。%Endophytic bacteria colonizes in healthy plant tissue, and formes a harmonious relationship with their hosts during a long coevolutionary process. Endophytic bacteria has been widely used in biological control of plant disease due to a variety of biological functions, such as disease resistance,growth promotion,nitrogen fixation, bioremediation and so on. In recent years, the biological control potential and integrated control effect of endophytic bacteria have been en⁃hanced by the technology of genetic engineering.This paper summarized the research achievements of endophytic bacteria at home and abroad, involving the aspects of concept, classification, identification methods of endophytic bacteria, and the interaction of endophytic bacteria with their hosts. Moreover, the phytoremediation capacity of endophytic bacteria, the potential applications and problems of endophytic bacteria on agricultural and forestry biocontrol were mainly dis⁃cussed.

  13. 生防解淀粉芽胞杆菌(Bacillus amyloliquefaciens)最新研究进展%The Latest Advances in Bio-Control Bacillus amyloliquefaciens

    Institute of Scientific and Technical Information of China (English)

    李红晓; 张殿朋; 卢彩鸽; 赵洪新

    2016-01-01

    Bacillus amyloliquefaciens is a strain similar to B. subtilis,a beneficial microbe that can produce spore, Gram-positive,and possessing biocontrolling activity. During its metabolism it produces antibiotic substance,a varie-ty of antibiotic preparations or antibiotic extracts with broad antibiotic spectrum,non toxic,non harms,non residues, long effectiveness for a given period of time,and other advantages. It can be widely applied in keeping fruits and vegetables fresh,and in biocontrolling microbial pests during their growth and post-harvest. It is a very ideal biocon-trolling microbe with the most developing value. In this paper the studies,the current application of B. amyloliquefa-ciens were drawn and summarized from aspect of the antibiotic mechanism,the antibiotic gene component,the estab-lishment of genetic engineering strain,the development of resistance products,the controlling against microbial pests,and other aspects,and accordingly to provide references for its large-scale safety application in agricultural bio-engineering.%解淀粉芽胞杆菌(Bacillus amyloliquefaciens)是与枯草芽胞杆菌相似,可产芽胞、革兰阳性(G +)、具有生防活性的益生细菌。其代谢过程中产生的抗菌物质种类多、抗菌谱广,其抗菌制剂或抗菌提取物具有无毒、无害、无残留、抑菌时效长等优点,可广泛应用于果蔬保鲜、果蔬生长期及采后微生物病害的生物防治,是极具开发价值的生防菌。本文从抗菌机理、抗性基因组成、基因工程菌构建、抗性产品开发及对微生物病害防治等几个方面,对解淀粉芽胞杆菌的研究及应用现状进行了归纳和总结,为其在农业生物工程中的规模化安全应用提供参考。

  14. Distribución Diferencial de Bacterias con Potencial Biocontrolador de Spongospora subterranea en Plantas de Papa (Solanum tuberosum cv. Diacol Capiro Differential Distrubution of Candidadate Biocontrol Bacteria against Spongospora subterranea in Potato Plants (Solanum tuberosum cv. Diacol Capiro

    Directory of Open Access Journals (Sweden)

    Juliana Soler Arango

    2012-06-01

    Full Text Available Resumen. La búsqueda de microorganismos promisorios para biocontrol de patógenos de plantas en el suelo con frecuencia se ha orientado a la detección de productores de hormonas y enzimas líticas, condiciones asociadas a su capacidad para promover crecimiento vegetal. Sin embargo, el suelo es altamente variable en escalas pequeñas y se conoce poco sobre la distribución espacial de microorganismos que expresan esas funciones. Este estudio determinó la capacidad de producción de indoles totales y quitinasas en bacterias cultivables aisladas del interior de la raíz, la rizósfera, la superficie de los tubérculos o suelo de un cultivo de papa (Solanum tuberosum variedad Diacol Capiro. Las muestras se obtuvieron en un campo comercial en el municipio de la Unión en el departamento de Antioquia, Colombia, en plantas que presentaban síntomas de infección por Spongospora subterranea. Se encontró una producción diferencial de indoles o quitinasas según el sitio de aislamiento de las bacterias. No se encontró una alta producción de ambas actividades en un sólo aislamiento, la mayor producción de indoles totales y quitinasas se encontró en bacterias aisladas a partir de raíz y rizósfera, comparada con las aisladas de tubérculos y suelo. Estos resultados sugieren que en el suelo no es aleatoria la distribución de funciones deseables en controladores biológicos. Con estos resultados es posible orientar su búsqueda para optimizar el uso de recursos y el desarrollo de nuevos bioproductos.Abstract. Searching for promising microorganisms to biocontrol soil-borne plant pathogens has been often focused on producers of hormone and lytic enzymes, since these traits are linked to plant growth promotion. However, the environment from inner roots to bulk soil is quite variable, and little is known about the spatial distribution of microorganisms expressing these desirable traits. Using potato plants (Solanum tuberosum var. Diacol Capiro from a

  15. Potential for Water Salvage by Release of the Biocontrol Beetle, Diorhabda carinulata, on Tamarisk (Tamarix ramosissima) Dominated Western U.S. Rivers

    Science.gov (United States)

    Murray, R. S.; Nagler, P. L.; van Riper, C.; Bean, D.; Glenn, E. P.

    2009-12-01

    The biocontrol beetle, Diorhabda carinulata, has been widely released in the upper basin of the Colorado River to control Tamarisk in the western U.S. A primary motivation for beetle release is to salvage water that would otherwise be lost to transpiration by Tamarisk. We summarize preliminary findings of our assessment of tamarisk, beetle and avian phenology and tamarisk water usage. We used the Enhanced Vegetation Index (EVI) from the MODIS sensors on the Terra satellite to evaluate the prospects for water salvage at 15 riparian release sites in Utah, Colorado, Nevada and Wyoming. EVI was combined with meteorological data to estimate evapotranspiration (ET) at the release sites and in adjacent sites to which the beetle might have spread. ET was estimated at 16-day intervals from 2000 to 2008, encompassing pre-release and post-release periods at each site. Baseline ET rates tended to be low, from 2-6 mm d-1 in summer (less than half of potential ET). At 4 of 15 sites, ET rates estimated by MODIS EVI decreased markedly one to two years after release. At other sites, however, no decrease in ET was detected, and ET tended to recover to pre-release levels at affected sites. Ground observations confirmed that beetles were active at all sites following release, defoliating stands of Tamarisk over areas as large as 200 ha. Along approximately 300 km of the Dolores and Colorado Rivers, ground based monitoring of tamarisk defoliation and refoliation was done using hand held GPS units and GIS software. Monitoring here began at the time beetles entered the system in 2004. Selected sites (15 ha) were also monitored for beetle presence and life stage as well as tamarisk condition. Additional ground data collected at four sites on the Dolores River includes vegetation structure, composition and phenology as well as bird monitoring and productivity. The four sites are dominated by saltcedar, with components of willow and cottonwood. For the last 3 years, monthly monitoring of

  16. Survivorship and feeding preferences among size classes of outplanted sea urchins, Tripneustes gratilla, and possible use as biocontrol for invasive alien algae

    Science.gov (United States)

    Ringang, Rory R.; Cantero, Sean Michael A.; Toonen, Robert J.

    2015-01-01

    We investigate the survivorship, growth and diet preferences of hatchery-raised juvenile urchins, Tripneustes gratilla, to evaluate the efficacy of their use as biocontrol agents in the efforts to reduce alien invasive algae. In flow-through tanks, we measured urchin growth rates, feeding rates and feeding preferences among diets of the most common invasive algae found in Kāneʻohe Bay, Hawaiʻi: Acanthophora spicifera, Gracilaria salicornia, Eucheuma denticulatum and Kappaphycus clade B. Post-transport survivorship of outplanted urchins was measured in paired open and closed cages in three different reef environments (lagoon, reef flat and reef slope) for a month. Survivorship in closed cages was highest on the reef flat (∼75%), and intermediate in the lagoon and reef slope (∼50%). In contrast, open cages showed similar survivorship on the reef flat and in the lagoon, but only 20% of juvenile urchins survived in open cages placed on the reef slope. Urchins grew significantly faster on diets of G. salicornia (1.58 mm/week ± 0.14 SE) and Kappaphycus clade B (1.69 ± 0.14 mm/wk) than on E. denticulatum (0.97 ± 0.14 mm/wk), with intermediate growth when fed on A. spicifera (1.23 ± 0.11 mm/wk). Interestingly, urchins display size-specific feeding preferences. In non-choice feeding trials, small urchins (17.5–22.5 mm test diameter) consumed G. salicornia fastest (6.08 g/day ± 0.19 SE), with A. spicifera (4.25 ± 0.02 g/day) and Kappaphycus clade B (3.83 ± 0.02 g/day) intermediate, and E. denticulatum was clearly the least consumed (2.32 ± 0.37 g/day). Medium-sized (29.8–43.8 mm) urchins likewise preferentially consumed G. salicornia (12.60 ± 0.08 g/day), with less clear differences among the other species in which E. denticulatum was still consumed least (9.35 ± 0.90 g/day). In contrast, large urchins (45.0–65.0 mm) showed no significant preferences among the different algae species at all (12.43–15.24 g/day). Overall consumption rates in non

  17. Survivorship and feeding preferences among size classes of outplanted sea urchins, Tripneustes gratilla, and possible use as biocontrol for invasive alien algae.

    Science.gov (United States)

    Westbrook, Charley E; Ringang, Rory R; Cantero, Sean Michael A; Toonen, Robert J

    2015-01-01

    We investigate the survivorship, growth and diet preferences of hatchery-raised juvenile urchins, Tripneustes gratilla, to evaluate the efficacy of their use as biocontrol agents in the efforts to reduce alien invasive algae. In flow-through tanks, we measured urchin growth rates, feeding rates and feeding preferences among diets of the most common invasive algae found in Kāne'ohe Bay, Hawai'i: Acanthophora spicifera, Gracilaria salicornia, Eucheuma denticulatum and Kappaphycus clade B. Post-transport survivorship of outplanted urchins was measured in paired open and closed cages in three different reef environments (lagoon, reef flat and reef slope) for a month. Survivorship in closed cages was highest on the reef flat (∼75%), and intermediate in the lagoon and reef slope (∼50%). In contrast, open cages showed similar survivorship on the reef flat and in the lagoon, but only 20% of juvenile urchins survived in open cages placed on the reef slope. Urchins grew significantly faster on diets of G. salicornia (1.58 mm/week ± 0.14 SE) and Kappaphycus clade B (1.69 ± 0.14 mm/wk) than on E. denticulatum (0.97 ± 0.14 mm/wk), with intermediate growth when fed on A. spicifera (1.23 ± 0.11 mm/wk). Interestingly, urchins display size-specific feeding preferences. In non-choice feeding trials, small urchins (17.5-22.5 mm test diameter) consumed G. salicornia fastest (6.08 g/day ± 0.19 SE), with A. spicifera (4.25 ± 0.02 g/day) and Kappaphycus clade B (3.83 ± 0.02 g/day) intermediate, and E. denticulatum was clearly the least consumed (2.32 ± 0.37 g/day). Medium-sized (29.8-43.8 mm) urchins likewise preferentially consumed G. salicornia (12.60 ± 0.08 g/day), with less clear differences among the other species in which E. denticulatum was still consumed least (9.35 ± 0.90 g/day). In contrast, large urchins (45.0-65.0 mm) showed no significant preferences among the different algae species at all (12.43-15.24 g/day). Overall consumption rates in non-choice trials

  18. Survivorship and feeding preferences among size classes of outplanted sea urchins, Tripneustes gratilla, and possible use as biocontrol for invasive alien algae

    Directory of Open Access Journals (Sweden)

    Charley E. Westbrook

    2015-09-01

    Full Text Available We investigate the survivorship, growth and diet preferences of hatchery-raised juvenile urchins, Tripneustes gratilla, to evaluate the efficacy of their use as biocontrol agents in the efforts to reduce alien invasive algae. In flow-through tanks, we measured urchin growth rates, feeding rates and feeding preferences among diets of the most common invasive algae found in Kāneʻohe Bay, Hawaiʻi: Acanthophora spicifera, Gracilaria salicornia, Eucheuma denticulatum and Kappaphycus clade B. Post-transport survivorship of outplanted urchins was measured in paired open and closed cages in three different reef environments (lagoon, reef flat and reef slope for a month. Survivorship in closed cages was highest on the reef flat (∼75%, and intermediate in the lagoon and reef slope (∼50%. In contrast, open cages showed similar survivorship on the reef flat and in the lagoon, but only 20% of juvenile urchins survived in open cages placed on the reef slope. Urchins grew significantly faster on diets of G. salicornia (1.58 mm/week ± 0.14 SE and Kappaphycus clade B (1.69 ± 0.14 mm/wk than on E. denticulatum (0.97 ± 0.14 mm/wk, with intermediate growth when fed on A. spicifera (1.23 ± 0.11 mm/wk. Interestingly, urchins display size-specific feeding preferences. In non-choice feeding trials, small urchins (17.5–22.5 mm test diameter consumed G. salicornia fastest (6.08 g/day ± 0.19 SE, with A. spicifera (4.25 ± 0.02 g/day and Kappaphycus clade B (3.83 ± 0.02 g/day intermediate, and E. denticulatum was clearly the least consumed (2.32 ± 0.37 g/day. Medium-sized (29.8–43.8 mm urchins likewise preferentially consumed G. salicornia (12.60 ± 0.08 g/day, with less clear differences among the other species in which E. denticulatum was still consumed least (9.35 ± 0.90 g/day. In contrast, large urchins (45.0–65.0 mm showed no significant preferences among the different algae species at all (12.43–15.24 g/day. Overall consumption rates in non

  19. 生防放线菌的酶学特性及其代谢产物%Enzymatic Characteristics and Metabol ites of Biocontrol Actinomycetes

    Institute of Scientific and Technical Information of China (English)

    李堆淑

    2015-01-01

    为获得更多特异性各异的生防放线菌,采用皿内琼脂块法和试管斜面划线法,对从陕西省商洛市土壤分离的11株生防放线菌菌株(MX1,MX2,MX3,MX4,MX5,MX6,MX7,MX8,MX9,SY1,SY2)和供试细黄链霉菌进行生理生化试验。结果表明:有8株菌株产脂肪酶,SY1、MX1和细黄链霉菌的浑浊圈很明显,直径大于15 mm 的菌株共计4株;有10株菌株产生卵磷脂酶,直径大于15 mm 的菌株共计5株;有11株菌株对淀粉的水力较强,直径大于15 mm 的共计6株;仅4株菌株可水解酪蛋白。12株供试菌株革兰氏染色均呈阳性;V-P 试验,MX1、MX2和 SY1呈阳性,MX6呈弱阳性;甲基红试验,MX2、MX3和细黄链霉菌呈阳性,MX9呈弱阳性;共有9株菌株可使明胶液化,占供试菌株的75%;仅 SY2产纤维素酶,有3株菌株产过氧化氢酶;有2株菌株能使牛奶培养基凝固,4株菌株能使其胨化。%The biophysical and biochemical test of 11 actinomycetes strains(MX1,MX2,MX3,MX4, MX5,MX6,MX7,MX8,MX9,SY1 and SY2)isolated from soil of Shangluo City in Shaanxi and tested Streptomyces microflavus was conducted by the agar block and test-tube slant streak plate methods to obtain more biocontrol actinomycetes with different specificities.Results:The diameter of hydrolyzation circle of 4 strains from 8 strains with producing lipase is more than 15 mm, and SY1, MX1 and Streptomyces microflavus strains have obvious hydrolyzation circles.The diameter of hydrolyzation circle of 5 strains from 10 strains with producing lecithinase is more than 15 mm.The diameter of hydrolyzation circle of 6 strains from 11 strains with strong starch hydrolysis capacity is more than 15 mm.4 strains can hydrolyze casein.12 tested strains present positive in gram stain test.MX1,MX2 and SY1 strains present positive and MX6 strain presents weakly positive in V-P test.MX2,MX3 and Streptomyces microflavus strains present positive and

  20. Potential analysis of grass endophytes Neotyphodium as biocontrol agents%禾草内生真菌作为生防因子的潜力分析

    Institute of Scientific and Technical Information of China (English)

    李秀璋; 姚祥; 李春杰; 南志标

    2015-01-01

    Many grasses in the subfamily Pooideae develop symbioses with Neotyphodium fungal endophytes, which exist widely in nature. The stably symbiotic relationship not only ensures accessible nutrients required by Neotypho-dium fungal endophytes, but also significantly increases the resistance of host grasses to biological stresses through the production of secondary metabolites. Previous studies show that infected grasses with endophytic fungi have prominently enhanced resistance to pests, plant diseases, companion plants and other biological stresses. Grass endophytic fungi show remarkable resistant to at least 79 species of pests from three classes;arachnida, nematode and insecta, and to at least 22 species of pathogenic fungi. Although the biotechnological application of endophytic fungi in grass breeding for variety selection and quality improvement has progressed well, opportunities remain for further exploring the use of fungal endophytes among different host grasses coupled with the examination of genetic stability of Neotyphodium in novel host grasses. In the future application of endophytic fungi as a bio-control method, researchers should not only consider specificities of host grasses, but also need to have comprehensive analysis and knowledge about the mutual relationships among grasses, endo-phytic fungi and ecological environments, which will help use endophytic fungi to better serve humanity.%早熟禾亚科多种禾草可与Neotyphodium内生真菌形成禾草-内生真菌共生体,这种植物-微生物共生体性状较为稳定,且在自然界中广泛存在。禾草-内生真菌共生体稳定的互利共生关系不但保证了内生真菌所需的全部营养物质,而且共生体产生的次生代谢物又可显著提高宿主禾草对生物胁迫的抗逆性。众多研究表明,内生真菌的侵染可显著提高宿主禾草对虫害、病害及伴生植物等多种生物胁迫的抗性。据不完全统计,禾草内生真菌对蛛

  1. Weed biocontrol in landscape restoration

    Science.gov (United States)

    Weed biological control programs in natural areas are often undertaken with the goal of restoring native plant communities and/or ecosystem services to a pre-invasion level. These objectives may be achieved in some areas with biological control alone; however, in other sites integration of biologica...

  2. Demographic Modelling in Weed Biocontrol

    Science.gov (United States)

    Demographic matrix modeling of plant populations can be a powerful tool to identify key life stage transitions that contribute the most to population growth of an invasive plant and hence should be targeted for disruption. Therefore, this approach has the potential to guide the pre-release selection...

  3. Biocontrol Methods in Cotton Management

    Institute of Scientific and Technical Information of China (English)

    SHOIRA Ashuralieva

    2008-01-01

    @@ The quantity of bio-laboratories and bio-factories in Uzbekistan increases every year.In 1970,there were only 4,in 1971,16,in 1985,710,in 1990,774,and in 2000,790.At present there are 864 biofactories and biolahoratories in our Republic,which produce trichograrnma,bracons,and golden eyes.Currently they make 9953.5 kg of trichogramma,2814.8 million individuals of bracon,and 3162.9 million individuals of goldeneyes.It has been achieved great successes in development and introduction of biological method of plant protection in our Republic at last time.In 1970,the area of this method was 2.6 thousand hectares,in 1971,12.5 thousand hectares,in 1985,3622 thousand hectares,in 1990,5919 thousand hectares,in 2000,7574 thousand hectares,and in 2007,10893 thousand hectares (85.7% of total crop area of our Republic).It will be planned to increase the biological method of plant protection in Uzbekistan by Program of integrated plant protection from pests, diseases and weeds in 2008.The big attention will be given to construction the new 83 bio-laborato-ries.

  4. Compatibilidade de Dicyma pulvinata com defensivos agrícolas e eficiência do biocontrole do mal-das-folhas da seringueira em campo Compatibility of Dicyma pulvinata with pesticides and biocontrol efficiency of South American leaf blight of rubber tree under field conditions

    Directory of Open Access Journals (Sweden)

    Débora Ferreira Melo

    2008-02-01

    Full Text Available O objetivo deste trabalho foi avaliar quatro isolados do fungo antagonista Dicyma pulvinata quanto à compatibilidade com defensivos agrícolas e adjuvantes, e a eficiência desses isolados no controle do mal-das-folhas (Microcyclus ulei da seringueira (Hevea sp. em campo. A compatibilidade dos isolados com defensivos e adjuvantes foi avaliada com base no crescimento micelial e na esporulação do fungo, em testes conduzidos in vitro. Para avaliação da eficiência do antagonista contra M. ulei, em campo, os quatros isolados do antagonista foram comparados ao controle exercido pelo tratamento com os fungicidas propiconazol + mancozeb. Os ensaios conduzidos em laboratório indicaram a incompatibilidade de D. pulvinata com os fungicidas benomyl, carbendazim, mancozeb, propiconazol e, ainda, com o inseticida acaricida endosulfan. Dois dos adjuvantes testados (Tween 20 e Tween 80 não afetaram o desenvolvimento do fungo. Foi comprovada a ação do antagonista D. pulvinata sobre M. ulei, em campo, com destaque para os isolados CEN 62 e CEN 93, que apresentaram eficiência de controle semelhante ao tratamento fungicida padrão.The objective of this work was to evaluate four isolates of the antagonist fungus Dicyma pulvinata in terms of its compatibility with chemical pesticides and adjuvants products, and the efficiency of these isolates as biocontrol agent against South American leaf blight (Microcyclus ulei of rubber tree (Hevea sp. under field conditions. Isolates compatibility with chemical pesticides and adjuvants was evaluated on mycelial growth and fungus sporulation in vitro. To assess the efficiency of the antagonist against M. ulei under field conditions, the four isolates were compared to the control by the fungicide mixture propiconazol + mancozeb. The assays showed incompatibility of the antagonistic fungus with the fungicides benomyl, carbendazim, mancozeb, propiconazol, besides the insecticide-acaricide endosulfan. Two of the adjuvants

  5. Biocontrol Ability and Action Mechanism of Starmerella bacillaris (Synonym Candida zemplinina) Isolated from Wine Musts against Gray Mold Disease Agent Botrytis cinerea on Grape and Their Effects on Alcoholic Fermentation.

    Science.gov (United States)

    Lemos, Wilson J; Bovo, Barbara; Nadai, Chiara; Crosato, Giulia; Carlot, Milena; Favaron, Francesco; Giacomini, Alessio; Corich, Viviana

    2016-01-01

    Gray mold is one of the most important diseases of grapevine in temperate climates. This plant pathogen affects plant growth and reduces wine quality. The use of yeasts as biocontrol agents to apply in the vineyard have been investigated in recent years as an alternative to agrochemicals. In this work, fermenting musts obtained from overripe grape berries, therefore more susceptible to infection by fungal pathogens such as Botrytis cinerea, were considered for the selection of yeasts carrying antifungal activity. Thirty-six isolates were identified as Starmerella bacillaris, a species recently proven to be of enological interest. Among them 14 different strains were studied and antifungal activity against B. cinerea was demonstrated, for the first time, to be present in S. bacillaris species. The production of volatile organic compounds (VOCs), tested in vitro, was found to be the main responsible of S. bacillaris antifungal effects. All the strains were able to reduce B. cinerea decay on wounded grape berries artificially inoculated with gray mold. The colonization level of wound was very high reaching, after 5 days, a concentration of 10(6) cells per ml of grape juice obtained after berry crushing. At this cell concentration S. bacillaris strains were used to ferment synthetic and natural musts. The sequential yeast inoculation, performed by adding S. cerevisiae 48 h after S. bacillaris, was needed to complete sugar consumption and determined a significant increase in glicerol content and a reduction of ethanol and acetic acid concentrations. The high wound colonization ability, found in this work, together with the propensity to colonize grape berry and the interesting enological traits possessed by the selected S. bacillaris strains allow the use of this yeast as biocontrol agent on vine and grape berries with possible positive effects on must fermentation, although the presence of S. cerevisiae is needed to complete the fermentation process. This work

  6. Induction of banana Fusarium Wilt disease with biocontrol bacteria and pathogen by inoculation%接种生防菌和病原菌对香蕉抗枯萎病的诱导

    Institute of Scientific and Technical Information of China (English)

    薛玉潇; 贾慧升; 王国芬; 刘磊; 黄俊生

    2012-01-01

    Banana vitroplants of 4--5 leaves were inoculated in different ways with two biocontrol bacteria Bacillus subtilis strains A5-6 and C10-1 and the banana Fusarium wilt pathogen (Foc4) to observe their changes of polyphenol oxidase ( PPO), peroxidase (POD) and phenylalanine ammonialyase (PAL) activities in leaves, which are related to plant tolerance to the disease. The PPO, POD and PAL activities in the leaves of the banana plants were determined by using the physiological and biochemical methods. The banana plants inoculated with the strains A5 -6 and C10-1 separately showed higher leaf PPO, POD and PAL activities than those inoculated with the sterile water control, and the banana plants inoculated with mixture of the biocontrol bacteria and Foc4 pathogen had higher leaf PPO, POD and PAL activities than those inoculated with Foc4 alone.%使用2株生防枯草芽孢杆菌A5-6,C10-1和香蕉枯萎病病原菌(Foc4),以不同的接种方式对4~5叶香蕉组培苗进行根部接种,以苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)这3种与植物抗病性密切相关的酶活性变化为指标,研究植物产生抗性的时间和强度的变化趋势。结果表明,经过生防菌A5-6和C10-1诱导处理的叶片PAL,POD,PPO的活性均高于对照(CK),生防菌和病原菌混合接种处理的POD和PPO酶活峰值高于生防菌和病原菌单独接种的处理。