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Sample records for biocontrol harlequin ladybird

  1. Evolution in biocontrol strains: insight from the harlequin ladybird Harmonia axyridis

    OpenAIRE

    Tayeh, Ashraf; Estoup, Arnaud; Laugier, Guillaume; Loiseau, Anne; Turgeon, Julie; Toepfer, Stefan

    2012-01-01

    After being used as a biocontrol agent against aphids for decades without harmful consequences, the Asian harlequin ladybird Harmonia axyridis has suddenly become an invasive pest on a worldwide scale. We investigate the impact of captive breeding on several traits of this ladybird such as genetic diversity, fecundity, survival and pathogen resistance. We conducted an experiment in the laboratory to compare the fecundity and the susceptibility to the entomopathogenic fungus Beauveria bassiana...

  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. 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

    In aphidophagous insect communities invaded by the harlequin ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), intraguild predation (IGP) is widely implicated in the displacement of native predators, however, indirect trophic interactions are rarely assessed. Using molecular gut-cont...... investigation. Our results emphasize the need to incorporate indirect interactions in studies of insect communities following invasion, not least because they potentially affect more species than direct interactions alone....

  4. 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. This is the fi...... first record of entomopathogenic fungi infecting larvae and pupae. Winter mortality due to fungal infection reached 17.9% in adults collected at one location. The larval stage was most susceptible to fungal infection, as confirmed through bioassay with I. farinosa....

  5. Expression and characterization of a recombinant i-type lysozyme from the harlequin ladybird beetle Harmonia axyridis.

    Science.gov (United States)

    Beckert, A; Wiesner, J; Schmidtberg, H; Lehmann, R; Baumann, A; Vogel, H; Vilcinskas, A

    2016-06-01

    Lysozymes are enzymes that destroy bacterial cell walls by hydrolysing the polysaccharide component of peptidoglycan. In insects, there are two classes of lysozymes, the c-type with muramidase activity and the i-type whose prototypical members from annelids and molluscs possess both muramidase and isopeptidase activities. Many insect genes encoding c-type and i-type lysozymes have been identified during genome and transcriptome analyses, but only c-type lysozymes have been functionally characterized at the protein level. Here we produced one of five i-type lysozymes represented in the immunity-related transcriptome of the invasive harlequin ladybird beetle Harmonia axyridis as recombinant protein. This was the only one containing the serine and histidine residues that are thought to be required for isopeptidase activity. This i-type lysozyme was recombinantly expressed in the yeast Pichia pastoris, but the purified protein was inactive in both muramidase and isopeptidase assays. Transcription and immunofluorescence analysis revealed that this i-type lysozyme is produced in the fat body but is not inducible by immune challenge. These data suggest that i-type lysozymes in insects may have acquired novel and as yet undetermined functions in the course of evolution. PMID:26778648

  6. The invasion history, distribution and colour pattern forms of the harlequin ladybird beetle Harmonia axyridis (Pall. (Coleoptera, Coccinellidae in Slovakia, Central Europe

    Directory of Open Access Journals (Sweden)

    Ľubomír Panigaj

    2014-05-01

    Full Text Available The harlequin ladybird beetle Harmonia axyridis (Coleoptera, Coccinellidae has invaded and established in Slovakia. Following unintentional introduction in 2008, the spread of the alien coccinellid was very fast. By the end of 2009, it was recorded across the whole country, and by the end of 2012 it was widely distributed and common in various habitats, particularly gardens, orchards and urban areas, where it was most frequent on trees. The rate of eastward spread was approximately 200 km year-1, similar to the overall rate of spread in Europe. Between 2008 and 2012, the coccinellid was recorded in a total of 153 localities, in altitudes ranging from 98 to 1,250 m. Most records of this species were made in lowlands, hilly areas and valleys separating mountain ridges. However, it was only rarely documented in areas above 700 m a.s.l. The non-melanic colour form (f. succinea was dominant along alongitudinal transect including eight urban areas across Slovakia, with the frequency of melanic forms (f. spectabilis and f. conspicua together between 6.3 and 19.2% and a median equal to 10.5%. The invasion history and distribution of H. axyridis in Slovakia are discussed with regard to the time sequence of records, rate of spread, altitudinal distribution, anthropogenic dispersal, effective recording, proportion of melanic forms and other relevant aspects associated with the spread of this successful invader.

  7. Genetics Home Reference: harlequin ichthyosis

    Science.gov (United States)

    ... harlequin ichthyosis with moderate clinical severity. J Invest Dermatol. 2006 Jul;126(7):1518-23. Epub 2006 ... of severe congenital ichthyosis of the neonate. J Dermatol Sci. 1999 Sep;21(2):96-104. Review. ...

  8. 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; Aebi, Alexandre

    2016-01-01

    frequency of IGP by H. axyridis was low: 2.7 % of larvae and 3.4 % of adults tested positive for A. nemoralis DNA. The presence of lime aphid DNA in predators was higher: 56.5 and 47.9 % of H. axyridis larvae and adults, respectively, contained E. tiliae DNA, whereas 60.8 % of adult A. nemoralis tested...

  9. Predator efficiency reconsidered for a ladybird-aphid system

    Czech Academy of Sciences Publication Activity Database

    Kindlmann, Pavel; Yasuda, H.; Kajita, Y.; Sato, S.; Dixon, Anthony F. G.

    2015-01-01

    Roč. 3, mar (2015), s. 27. ISSN 2296-701X R&D Projects: GA MŠk(CZ) LO1415; GA ČR GB14-36098G Institutional support: RVO:67179843 Keywords : biological control * generation time ratio * population dynamics * predator-prey systems * ladybirds * aphids Subject RIV: EH - Ecology, Behaviour

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Effects of ACTH, capture, and short term confinement on glucocorticoid concentrations in harlequin ducks (Histrionicus histrionicus)

    Science.gov (United States)

    Nilsson, P.B.; Hollmén, Tuula E.; Atkinson, S.; Mashburn, K.L.; Tuomi, P.A.; Esler, Daniel; Mulcahy, D.M.; Rizzolo, D.J.

    2008-01-01

    Little is known about baseline concentrations of adrenal hormones and hormonal responses to stress in sea ducks, although significant population declines documented in several species suggest that sea ducks are exposed to increased levels of environmental stress. Such declines have been observed in geographically distinct harlequin duck populations. We performed an adrenocorticotropic hormone (ACTH) challenge to evaluate adrenal function and characterize corticosterone concentrations in captive harlequin ducks and investigated the effects of capture, surgery, and short term confinement on corticosterone concentrations in wild harlequin ducks. Harlequin ducks responded to the ACTH challenge with an average three-fold increase in serum corticosterone concentration approximately 90??min post injection, and a four- to five-fold increase in fecal glucocorticoid concentration 2 to 4??h post injection. Serum corticosterone concentrations in wild harlequin ducks increased within min of capture and elevated levels were found for several hours post capture, indicating that surgery and confinement maintain elevated corticosterone concentrations in this species. Mean corticosterone concentrations in wild harlequin ducks held in temporary captivity were similar to the maximum response levels during the ACTH challenge in captive birds. However, large variation among individuals was observed in responses of wild birds, and we found additional evidence suggesting that corticosterone responses varied between hatch year and after hatch year birds. ?? 2008.

  12. Invasive alien predator causes rapid declines of native European ladybirds

    DEFF Research Database (Denmark)

    Roy, Helen E.; Adriaens, Tim; Isaac, Nick J.B.;

    2012-01-01

    Aim Invasive alien species (IAS) are recognized as major drivers of biodiversity loss, but few causal relationships between IAS and species declines have been documented. In this study, we compare the distribution (Belgium and Britain) and abundance (Belgium, Britain and Switzerland) of formerly...... common and widespread native ladybirds before and after the arrival of Harmonia axyridis, a globally rapidly expanding IAS. Location Europe Methods We used generalized linear mixed-effects models (GLMMs) to assess the distribution trends of eight conspicuous and historically widespread and common species...... surveys of deciduous trees in Belgium, Britain and Switzerland. Results Five (Belgium) and seven (Britain) of eight species studied show substantial declines attributable to the arrival of H. axyridis. Indeed, the two-spot ladybird, Adalia bipunctata, declined by 30% (Belgium) and 44% (Britain) over 5...

  13. Evolution of slow and fast development in predatory ladybirds

    Czech Academy of Sciences Publication Activity Database

    Dixon, Anthony F. G.; Sato, S.; Kindlmann, Pavel

    2016-01-01

    Roč. 140, 1-2 (2016), s. 103-114. ISSN 0931-2048 R&D Projects: GA MŠk(CZ) LO1415; GA ČR GB14-36098G Institutional support: RVO:67179843 Keywords : aphid consumption * growth polymorphism * ladybirds * optimum growth rate * rate of development * survival Subject RIV: EH - Ecology, Behaviour Impact factor: 1.650, year: 2014

  14. Invasive alien predator causes rapid declines of native European ladybirds

    OpenAIRE

    Roy, Helen E; Adriaens, Tim; Isaac, Nick J. B.; Kenis, Marc; Onkelinx, Thierry; Martin, Gilles San; Brown, Peter M. J.; Hautier, Louis; Poland, Remy; Roy, David B.; Comont, Richard; Eschen, René; Frost, Robert; Zindel, Renate; Vlaenderen, Johan Van

    2012-01-01

    Aim  Invasive alien species (IAS) are recognized as major drivers of biodiversity loss, but few causal relationships between IAS and species declines have been documented. In this study, we compare the distribution (Belgium and Britain) and abundance (Belgium, Britain and Switzerland) of formerly common and widespread native ladybirds before and after the arrival of Harmonia axyridis, a globally rapidly expanding IAS.Location  EuropeMethods  We used generalized linear mixed-effects models (GL...

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 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. PMID:23448042

  17. Harlequin Infant Born to a Varicella Infected Mother: A Case Report.

    Science.gov (United States)

    Rajagopal, Meyyappa Devan; Ch Toi, Pampa; Plakkal, Nishad; Ayyanar, Pavithra

    2015-01-01

    Harlequin ichthyosis is a rare, severe form of congenital ichthyosis characterised by distinct physical appearance of the infant. It has occurrence of 1 in 1 million births and over 100 cases have been reported so far. It is caused by mutation in ABCA12 gene involved in lipid transport leading to profound thickening of stratum corneum. The mainstay of management relies on supportive care & administration of retinoid derivatives. Outcome is usually fatal and most of the babies die during neonatal period. In this article, we report a case of harlequin baby born of non-consanguineous marriage with history of chicken pox in the mother during first trimester of pregnancy. PMID:26083791

  18. Functional morphology and structural characteristics of wings of the ladybird beetle, Coccinella septempunctata (L.).

    Science.gov (United States)

    Xiang, Jinwu; Du, Jianxun; Li, Daochun; Zhen, Chong

    2016-06-01

    In recent years, the surface morphology and microstructure of ladybird (Coccinella septempunctata) wings have been used to help design the flapping-wing micro air vehicle (FWMAV). In this study, scanning electron microscopy (SEM) was used to verify the functional roles of the ladybird forewing and hindwing. Surface morphology and the cross-sectional microstructure of the wings are presented. Detailed morphology of ladybird forewings was observed using atomic force microscopy (AFM) and the composition of the wings was characterized using Fourier transformed infrared spectroscopy (FTIR). The ladybird forewing may possess different performance characteristics than the beetle, Allomyrina dichotoma. Additionally, the circular holes in the forewing might be important for decreasing the weight of the forewing and to satisfy requirements of mechanical behavior. Microsc. Res. Tech. 79:550-556, 2016. © 2016 Wiley Periodicals, Inc. PMID:27111868

  19. Seven-Spot Ladybird Optimization: A Novel and Efficient Metaheuristic Algorithm for Numerical Optimization

    OpenAIRE

    Peng Wang; Zhouquan Zhu; Shuai Huang

    2013-01-01

    This paper presents a novel biologically inspired metaheuristic algorithm called seven-spot ladybird optimization (SLO). The SLO is inspired by recent discoveries on the foraging behavior of a seven-spot ladybird. In this paper, the performance of the SLO is compared with that of the genetic algorithm, particle swarm optimization, and artificial bee colony algorithms by using five numerical benchmark functions with multimodality. The results show that SLO has the ability to find the best solu...

  20. The invasion history, distribution and colour pattern forms of the harlequin ladybird beetle Harmonia axyridis (Pall.) (Coleoptera, Coccinellidae) in Slovakia, Central Europe

    Czech Academy of Sciences Publication Activity Database

    Panigaj, L.; Zach, P.; Honěk, A.; Nedvěd, Oldřich; Kulfan, J.; Martínková, Z.; Selyemová, D.; Viglášová, S.; Roy, H. E.

    -, č. 412 (2014), s. 89-102. ISSN 1313-2989 Grant ostatní: Slovak Research and Development Agency(SK) APVV 0200/11; Grant Agency of Ministry of Education and SAS(SK) 1/1025/12; Grant Agency of Ministry of Education and SAS(SK) 2/0035/13; Grant Agency of Ministry of Education and SAS(SK) 2/0157/11; Mze ČR(CZ) QH82047; MŠMT ČR(CZ) 7AMB12SK141; EU COST(CZ) TD1209 Institutional support: RVO:60077344 Keywords : alien * altitude * colour morphs Subject RIV: EH - Ecology, Behaviour Impact factor: 0.933, year: 2014 http://europepmc.org/articles/PMC4042697;jsessionid=aEQnuIZkqJpBc2xpenqy.0

  1. Biocontrol agents in signalling resistance

    OpenAIRE

    Loon, L C; Pieterse, C.M.J.

    2002-01-01

    The mechanisms by which biological control agents suppress disease comprise competition for nutrients, notably iron, production of antibiotics, and secretion of lytic enzymes, as well as inducing resistance in the plant. The former three mechanisms act primarily on the pathogen by decreasing its activity, growth, and/or survival and require the biocontrol agent and the pathogen to be in close proximity. Because microorganisms with biocontrol properties and soilborne pathogens are both attract...

  2. Attractiveness of harlequin bug, Murgantia histrionica, aggregation pheromone: field response to isomers, ratios, and dose.

    Science.gov (United States)

    Weber, Donald C; Cabrera Walsh, Guillermo; DiMeglio, Anthony S; Athanas, Michael M; Leskey, Tracy C; Khrimian, Ashot

    2014-12-01

    A two-component pheromone, (3S,6S,7R,10S)- and (3S,6S,7R,10R)-10,11-epoxy-1-bisabolen-3-ol (murgantiol), present in emissions from adult male harlequin bugs, Murgantia histrionica, is most attractive in field bioassays to adults and nymphs in the naturally occurring ratio of ca. 1.4:1. Each of the two individual synthetic stereoisomers is highly attractive to male and female adults and nymphs, but is more attractive in combination and when deployed with a harlequin bug host plant. Blends of 8 stereoisomers also are highly attractive, suggesting that isomers not found in the natural pheromone are not repellent. Deployment of an inexpensive non-stereospecific synthetic pheromone holds promise for efficient trapping and/or use in trap-crops for this important pest in North America. PMID:25380993

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

    Directory of Open Access Journals (Sweden)

    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

  4. Seven-spot ladybird optimization: a novel and efficient metaheuristic algorithm for numerical optimization.

    Science.gov (United States)

    Wang, Peng; Zhu, Zhouquan; Huang, Shuai

    2013-01-01

    This paper presents a novel biologically inspired metaheuristic algorithm called seven-spot ladybird optimization (SLO). The SLO is inspired by recent discoveries on the foraging behavior of a seven-spot ladybird. In this paper, the performance of the SLO is compared with that of the genetic algorithm, particle swarm optimization, and artificial bee colony algorithms by using five numerical benchmark functions with multimodality. The results show that SLO has the ability to find the best solution with a comparatively small population size and is suitable for solving optimization problems with lower dimensions. PMID:24385879

  5. Seven-Spot Ladybird Optimization: A Novel and Efficient Metaheuristic Algorithm for Numerical Optimization

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2013-01-01

    Full Text Available This paper presents a novel biologically inspired metaheuristic algorithm called seven-spot ladybird optimization (SLO. The SLO is inspired by recent discoveries on the foraging behavior of a seven-spot ladybird. In this paper, the performance of the SLO is compared with that of the genetic algorithm, particle swarm optimization, and artificial bee colony algorithms by using five numerical benchmark functions with multimodality. The results show that SLO has the ability to find the best solution with a comparatively small population size and is suitable for solving optimization problems with lower dimensions.

  6. Rickettsial relative associated with male-killing in the ladybird beetle (Adalia bipunctata).

    OpenAIRE

    Werren, J.H.; Hurst, G.G.D.; Zhang, W.; Breeuwer, J.A.J.; Stouthamer, R; Majerus, M. E. N.

    1994-01-01

    A cytoplasmically inherited microorganism associated with male killing in the two-spot ladybird beetle, Adalia bipunctata, is shown to be closely related to bacteria in the genus Rickettsia. Sequencing of a PCR-amplified product of the 16S genes coding for rRNA (16S rDNA) shows the organism associated with male killing in ladybirds to share a common ancestry with the Rickettsias relative to other genera (e.g., Anaplasma, Ehrlichia, and Cowdria). The rickettsial 16S rDNA product is found in fo...

  7. Habitat or prey specialization in predatory ladybird beetles: a case study of two closely related species

    Czech Academy of Sciences Publication Activity Database

    Ferrer, A.; Dixon, Anthony F. G.; Hemptinne, J. L.

    -, - (2016). ISSN 0931-2048 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : aphids * habitat * ladybirds * prey * reproductive investment * specialization Subject RIV: EH - Ecology, Behaviour Impact factor: 1.650, year: 2014

  8. Does the volatile hydrocarbon profile differ between the sexes: a case study on five aphidophagous ladybirds.

    Science.gov (United States)

    Pattanayak, Rojalin; Mishra, Geetanjali; Omkar; Chanotiya, Chandan Singh; Rout, Prasant Kumar; Mohanty, Chandra Sekhar

    2014-11-01

    Insect hydrocarbons (HCs) primarily serve as a waterproofing cuticular layer and function extensively in chemical communication by facilitating species, sex, and colony recognition. In this study, headspace solid-phase microextraction is employed for investigating the sex-specific volatile HC profile of five ladybirds collected from Lucknow, India namely, Coccinella septempunctata (L.), Coccinella transversalis (Fabr.), Menochilus sexmaculatus (Fabr.), Propylea dissecta (Mulsant), and Anegleis cardoni (Weise) for the first time. Major compounds reported in C. septempunctata, C. transversalis, and A. cardoni are methyl-branched saturated HCs, whereas in M. sexmaculatus, and P. dissecta, they are unsaturated HCs. Other than A. cardoni, both the sexes of the other four ladybirds had similar compounds at highest peak but with statistically significant differences. However, in A. cardoni, which is a beetle with a narrow niche, the major compound in both male and female was different. The difference in volatile HC profile of the sexes of the five ladybirds indicates that gender-specific differences primarily exist due to quantitative differences in chemicals with only very few chemicals being unique to a gender. This variation in semiochemicals might have a role in behavioral or ecological aspects of the studied ladybirds. PMID:25060353

  9. Spotlight on the positive effects of the ladybird Harmonia axyridis on agriculture

    Science.gov (United States)

    In the midst of considerable negativity surrounding the ladybird Harmonia axyridis (Pallas), this paper sheds some light on the positive effects that this predator has had on agriculture. Using resources available at the USDA, National Agricultural Library (DigiTop literature database, Navigator pla...

  10. Fecundity and fertility of ladybird beetle Harmonia axyridis after prolonged cold storage

    Czech Academy of Sciences Publication Activity Database

    Awad, Mona; Kalushkov, P.; Nedvědová, T.; Nedvěd, Oldřich

    2013-01-01

    Roč. 58, č. 5 (2013), s. 657-666. ISSN 1386-6141 Grant ostatní: MZe ČR(CZ) QH82047 Institutional support: RVO:60077344 Keywords : ladybird * hatching rate * overwintering Subject RIV: ED - Physiology Impact factor: 2.253, year: 2013 http://link.springer.com/article/10.1007%2Fs10526-013-9512-4#

  11. 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.

  12. 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.

  13. 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". PMID:27570260

  14. Biocontrol mechanisms of Thrichoderma strains

    OpenAIRE

    Benítez Fernández, Concepción Tahía; Rincón Romero, Ana María; Limón Mirón, María del Carmen; Carballo Codón, Antonio

    2004-01-01

    The genus Trichoderma comprises a great number of fungal strains that act as biological control agents, the antagonistic properties of which are based on the activation of multiple mechanisms. Trichoderma strains exert biocontrol against fungal phytopathogens either indirectly, by competing for nutrients and space, modifying the environmental conditions, or promoting plant growth and plant defensive mechanisms and antibiosis, or directly, by mechanisms such as mycoparasitism. These indirect a...

  15. Postharvest Biocontrol: Introspection and Paradigm Shifts

    Science.gov (United States)

    The use of postharvest biocontrol agents as an alternative to the synthetic, chemical fungicides on a widespread basis has many constraints. During the last twenty years, the field of postharvest biocontrol research has significantly grown and developed and seen the creation of several products. Des...

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

    Science.gov (United States)

    Mulcahy, D.M.; Esler, Daniel

    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. ?? Wildlife Disease Association 2010.

  17. Loss from harlequin ducks of abdominally implanted radio transmitters equipped with percutaneous antennas

    Science.gov (United States)

    Mulcahy, D.M.; Esler, Daniel; Stoskopf, M.K.

    1999-01-01

    We documented extrusion and loss of abdominally implanted radio transmitters with percutaneous antennas from adult female Harlequin Ducks (Histrionicus histrionicus). Birds were captured during wing molt (late August to mid-September) in 1995-1997. Of 44 Harlequin Ducks implanted with radios and recaptured, 7 (16%) had lost their transmitters and 5 (11%) had radios in the process of extruding. Most (11 of 12) extrusions and losses occurred in birds implanted with radios in 1996 and recaptured in 1997. We suggest that transmitter extrusions and losses were due largely to changes in transmitter design made between 1095 and 1996. Transmitters implanted in 1996 were cylindrical rather than spherical, had a flat end with an abrupt edge, and the lower portion of the antenna was reinforced. Radio losses occurred after the 7-mo monitoring period and caused no apparent harm to the birds. Investigators using implanted radios with percutaneous antennas for long-term projects should be aware of the potential for radio extrusion and should minimize the problem by using transmitters that have no sharp edges and that are wide, rather than narrow.

  18. 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.

  19. Mechanisms involved in biocontrol by microbial inoculants

    OpenAIRE

    Dunne, Colum; Delany, Isabel; Fenton, Anne; O'Gara, Fergal

    1996-01-01

    Biological control offers alternative environmentally friendly strategies for the control of phytopathogens in agriculture and horticulture. Biocontrol metabolites are designed so that they do not have any adverse effects on host plants or on indigenous microflora and, in addition, resistance to these metabolites does not appear to develop. As promising alternatives to chemical pesticides, some biocontrol agents have been found to produce a variety of antifungal secondary metaboli...

  20. Targeted precision biocontrol and enhanced pollination

    OpenAIRE

    Hokkanen, Heikki; Boecking, Otto; Cokl, Andrej; Cotes, Belen; Eken, Cafer; Karise, Reet; Krajl, Jasna; Maccagnani, Bettina; Menzler-Hokkanen, Ingeborg; Mommaerts, Veerle; Mänd, Marika; Smagghe, Guy; Söderlund, Niklas; Tuncer, Serdar; Veromann, Eve

    2012-01-01

    BICOPOLL and BICOPOLL-NET connect 12 research units from 10 European countries and autonomous regions into a concerted effort to develop and bring into practice improved methods of biocontrol and pollination services, using strawberry as the case study. BICOPOLL partners will use bees to (i) precision deliver biocontrol agents to the flowers of the target crops to provide control of diseases, (ii) improve the pollination of horticultural crops.

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

    OpenAIRE

    Rebecca McCaffery; Richards-Zawacki, Corinne L.; Karen R Lips

    2015-01-01

    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. variu...

  2. Evaluating Group Housing Strategies for the Ex-Situ Conservation of Harlequin Frogs (Atelopus spp.) Using Behavioral and Physiological Indicators

    OpenAIRE

    Cikanek, Shawna J.; Simon Nockold; Brown, Janine L.; James W Carpenter; Angie Estrada; Jorge Guerrel; Katharine Hope; Roberto Ibáñez; Sarah B Putman; Brian Gratwicke

    2014-01-01

    We have established ex situ assurance colonies of two endangered Panamanian harlequin frogs, Atelopus certus and Atelopus glyphus, but observed that males fought with each other when housed as a group. Housing frogs individually eliminated this problem, but created space constraints. To evaluate the potential stress effects from aggressive interactions when grouping frogs, we housed male frogs in replicated groups of one, two, and eight. We measured aggressive behavioral interactions and feca...

  3. 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.

  4. 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.

  5. Phylogeography and demography of Guianan harlequin toads (Atelopus): diversification within a refuge.

    Science.gov (United States)

    Noonan, Brice P; Gaucher, Philippe

    2005-09-01

    We investigated the genetic structure of populations of Guianan harlequin toads (genus Atelopus) and their evolutionary affinities to extra-Guianan congeners. Phylogenetic analysis of mitochondrial cytochrome b (cyt b) and NADH dehydrogenase subunit 2 (ND2) gene sequences produced well-supported clades largely corresponding to the four recognized taxa in the Guianas (Atelopus spumarius hoogmoedi, Atelopus spumarius barbotini, Atelopus franciscus, and Atelopus flavescens). Our findings suggest that the Guianan A. spumarius represent distinct evolutionary lineages that merit distinction from Amazonian conspecifics, and that the status of A. flavescens and A. franciscus is somewhat less clear. Approximately 69% of the observed genetic variation is accounted for by differences between these four recognized taxa. Coalescent-based estimates of gene flow between taxa suggest that these lineages are largely isolated from one another. Negligible rates of migration between populations and significant divergence within such close proximity suggests that although the region inhabited by these taxa is almost entirely undisturbed, significant habitat heterogeneity exists as to have produced a remarkable diversification of Atelopus within the eastern Guiana Shield. These results contradict the commonly held view of the Guiana Shield as a 'refuge' whose stability during late Tertiary and Quaternary climatic fluctuations served as a biotic reservoir. Instead, we provide evidence that climatic fluctuations during this time had a diversifying effect within the Guianan region. PMID:16101771

  6. 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.

  7. 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

  8. Spread of the invasive ladybird Harmonia axyridis in the Czech Republic and Denmark

    DEFF Research Database (Denmark)

    Nedved, Oldrich; Steenberg, Tove; Harding, Susanne

    Spread of the invasive ladybird Harmonia axyridis in the Czech Republic and Denmark Oldřich Nedvěd1,2 and Tove Steenberg3 and SUSANNE HARDING4 1Faculty of Science, University of South Bohemia, and 2Institute of Entomology, Biology Centre; Branišovská 31, CZ370 05 České Budějovice, Czech Republic. 3......Faculty of Agricultural Sciences, University OF Aarhus, Skovbrynet 14, DK-2800 Kgs. Lyngby, Denmark 4 Faculty of Life Sciences, University of Copenhagen, Bülowsvej 13, DK - 1870 Frederiksberg C, Denmark nedved@prf.jcu.cz Introduction: Harmonia axyridis (Coleoptera: Coccinellidae) is an invasive alien...... that H. axyridis will continue to spread rapidly in Europe, particularly northwards and eastwards. Although there may consequently be a reduction in pest insects, our records support that this species may have significant detrimental impact. The records of the axyridis colour morph in the Czech Republic...

  9. 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. ?? 2007 by the Association of Avian Veterinarians.

  10. Climate and change in clines for melanism in the two-spot ladybird, Adalia bipunctata (Coleoptera: Coccinellidae)

    OpenAIRE

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

    1998-01-01

    The polymorphic two-spot ladybird, Adalia bipunctata, shows clinal variation in the frequency with which melanic and non-melanic morphs occur. Here we show that the clines in melanism in The Netherlands have changed over the past two decades: they have become shallower. This change has coincided with an increase in local ambient spring temperatures at most meteorological stations close to the sampling sites. The potential contribution of thermal melanism to the change in the shape of the clin...

  11. Molecular Characterization and Identification of Biocontrol Isolates of Trichoderma spp.

    OpenAIRE

    Hermosa, M. R.; Grondona, I; Iturriaga, E A; Diaz-Minguez, J. M.; Castro, C.; Monte, E.; Garcia-Acha, I.

    2000-01-01

    The most common biological control agents (BCAs) of the genus Trichoderma have been reported to be strains of Trichoderma virens, T. harzianum, and T. viride. Since Trichoderma BCAs use different mechanisms of biocontrol, it is very important to explore the synergistic effects expressed by different genotypes for their practical use in agriculture. Characterization of 16 biocontrol strains, previously identified as “Trichoderma harzianum” Rifai and one biocontrol strain recognized as T. virid...

  12. Biocontrol Agents for Take-all.

    OpenAIRE

    Raaijmakers, J. M.; Weller, D.M.; Thomashow, L S; Cook, R J

    1997-01-01

    Fluorescent Pseudomonas spp. are described which are effective for the control of diseases caused by the soil-borne fungus, Gaeumannomyces graminis (Gg), such as take-all, in small grain crops or turf grass. The subject biocontrol strains have a unique genotype as shown by a characteristic banding pattern, and exhibit root-colonizing ability which is characterized by both higher population density on roots and extended colonizing activity compared to known Gg-suppressive strains. A further pr...

  13. Complete Genome Sequence of Biocontrol Strain Pseudomonas fluorescens LBUM 223

    OpenAIRE

    Roquigny, Roxane; Arseneault, Tanya; Gadkar, Vijay J.; Novinscak, Amy; Joly, David L.; Filion, Martin

    2015-01-01

    Pseudomonas fluorescens LBUM 223 is a plant growth-promoting rhizobacterium (PGPR) with biocontrol activity against various plant pathogens. It produces the antimicrobial metabolite phenazine-1-carboxylic acid, which is involved in the biocontrol of Streptomyces scabies, the causal agent of common scab of potato. Here, we report the complete genome sequence of P. fluorescens LBUM 223.

  14. A blood survey of elements, viral antibodies, and hemoparasites in wintering Harlequin Ducks (Histrionicus histrionicus) and Barrow's Goldeneyes (Bucephala islandica)

    Science.gov (United States)

    Heard, D.J.; Mulcahy, D.M.; Iverson, S.A.; Rizzolo, D.J.; Greiner, E.C.; Hall, J.; Ip, H.; Esler, Daniel

    2008-01-01

    Twenty-eight Harlequin Ducks (Histrionicus histrionicus) and 26 Barrow's Goldeneyes (Bucephala islandica) were captured in Prince William Sound, Alaska, between 1 and 15 March 2005. Blood was collected for quantification of element concentrations, prevalence of antibodies to several viruses, and hemoparasite prevalence and identification. Although we found selenium concentrations that have been associated with selenosis in some birds (???.0 ppm ww), our findings contribute to a growing literature describing relatively high selenium in apparently healthy birds in marine environments. Avian influenza virus antibodies were detected in the plasma of 28% of the ducks. No antibodies against adenovirus, reovirus, or paramyxovirus 1 were detected. Several hemoparasite species were identified in 7% of ducks. Our findings are similar to those in other free-living marine waterfowl and do not indicate unusual concerns for the health of these species in this area in late winter. ?? Wildlife Disease Association 2008.

  15. Evaluating group housing strategies for the ex-situ conservation of harlequin frogs (Atelopus spp.) using behavioral and physiological indicators.

    Science.gov (United States)

    Cikanek, Shawna J; Nockold, Simon; Brown, Janine L; Carpenter, James W; Estrada, Angie; Guerrel, Jorge; Hope, Katharine; Ibáñez, Roberto; Putman, Sarah B; Gratwicke, Brian

    2014-01-01

    We have established ex situ assurance colonies of two endangered Panamanian harlequin frogs, Atelopus certus and Atelopus glyphus, but observed that males fought with each other when housed as a group. Housing frogs individually eliminated this problem, but created space constraints. To evaluate the potential stress effects from aggressive interactions when grouping frogs, we housed male frogs in replicated groups of one, two, and eight. We measured aggressive behavioral interactions and fecal glucocorticoid metabolite (GC) concentrations as indicators of stress in each tank. In both small and large groups, frogs initially interacted aggressively, but aggressive interactions and fecal GCs declined significantly after the first 2 weeks of being housed together, reaching the lowest levels by week 4. We conclude that aggressive interactions in same-sex groups of captive Atelopus may initially cause stress, but the frogs become habituated within a few weeks and they can safely be housed in same-sex groups for longer periods of time. PMID:24587290

  16. Evaluating group housing strategies for the ex-situ conservation of harlequin frogs (Atelopus spp. using behavioral and physiological indicators.

    Directory of Open Access Journals (Sweden)

    Shawna J Cikanek

    Full Text Available We have established ex situ assurance colonies of two endangered Panamanian harlequin frogs, Atelopus certus and Atelopus glyphus, but observed that males fought with each other when housed as a group. Housing frogs individually eliminated this problem, but created space constraints. To evaluate the potential stress effects from aggressive interactions when grouping frogs, we housed male frogs in replicated groups of one, two, and eight. We measured aggressive behavioral interactions and fecal glucocorticoid metabolite (GC concentrations as indicators of stress in each tank. In both small and large groups, frogs initially interacted aggressively, but aggressive interactions and fecal GCs declined significantly after the first 2 weeks of being housed together, reaching the lowest levels by week 4. We conclude that aggressive interactions in same-sex groups of captive Atelopus may initially cause stress, but the frogs become habituated within a few weeks and they can safely be housed in same-sex groups for longer periods of time.

  17. Investigating host plant selection of harlequin bug, Murgantia histrionica (Hahn), in order to improve a trap cropping system for its management.

    OpenAIRE

    Wallingford, Anna Kate

    2012-01-01

    Harlequin bug (HB), Murgantia histrionica (Hahn), is a pest of cole crops. Alternative control strategies were investigated for control of HB, including trap cropping and systemic neonicotinoid insecticide applications. Potential trap crops, mustard (Brassica juncea â Southern Giant Curledâ ), rapeseed (B. napus â Athenaâ ), rapini (B. rapa) and arugula (Eruca sativa) were preferred over collard (B. oleracea â Championâ ), and a non-brassica control, bean (Phaseolus vulgaris â Bron...

  18. 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...... assemblage of entomopathogenic fungal species with a different prevalence in coccinellids compared to their relative abundance in this habitat....

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

    Science.gov (United States)

    Howe, Andy G; Ravn, Hans Peter; Jensen, Annette B; Meyling, Nicolai V

    2016-09-01

    Occurrence of entomopathogenic fungi on phylloplanes in Tilia × europaea crowns between 1 and 13 m was assessed in urban parks. Prevalence of fungal infections in ladybirds (Coleoptera: Coccinellidae) collected from Tilia × europaea was assessed to determine whether fungi found on phylloplanes also 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 5-7 m. 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% Harmonia axyridis; 4.8% natives), Lecanicillium spp. (13.6% H. axyridis; 4.8% natives), with fewer Beauveria spp. infections (2.6% H. axyridis). Molecular identification revealed Beauveria bassiana, B. pseudobassiana, Isaria farinosa and Lecanicillium muscarium among isolates of both tree and ladybird origin. Tilia × europaea phylloplanes support a diverse assemblage of entomopathogenic fungal species with a different prevalence in coccinellids compared to their relative abundance in this habitat. PMID:27353660

  20. Vulnerability of larvae of two species of aphidophagous ladybirds, Adalia bipunctata Linnaeus and Harmonia axyridis Pallas, to cannibalism and intraguild predation

    Czech Academy of Sciences Publication Activity Database

    Sato, S.; Yasuda, H.; Evans, E.W.; Dixon, Anthony F. G.

    2009-01-01

    Roč. 12, č. 2 (2009), s. 111-115. ISSN 1343-8786 Institutional research plan: CEZ:AV0Z60870520 Keywords : cannibalism * chemical protection * Coccinellidae * intraguild predation * predatory ladybirds Subject RIV: EG - Zoology Impact factor: 0.663, year: 2009

  1. Genomic Basis of Plant Pathogen Suppression by Biocontrol Pseudomonas Species

    Science.gov (United States)

    Various plant commensal bacterial species, which naturally colonize the plant rhizosphere, are able to suppress fungal, bacterial, viral and even insect plant pathogens. These biocontrol activities are elicited primarily through the production of secreted exoenzymes and secondary metabolites that ma...

  2. Nitrogen fertilization impacts biocontrol of tomato gray mold

    OpenAIRE

    Abro, Manzoor Ali; Lecompte, François; Bardin, Marc

    2014-01-01

    Gray mold, caused by Botrytis cinerea, is a common threat for greenhouse production of tomatoes. Control of this disease can be difficult even with chemical treatments, and alternative methods are needed. Nitrogen (N) fertilization is known to modify the impact of pathogens on plants. However, there is scarce knowledge about the effect of fertilization on the efficacy of biocontrol. Here, we studied the effect of N fertilization on biocontrol agents Trichoderma atroviride and Microdochium dim...

  3. Influence of Environmental Parameters on Trichoderma Strains with Biocontrol Potential

    OpenAIRE

    Kredics, László; Antal, Zsuzsanna; Manczinger, László; Szekeres, András; Kevei, Ferenc; Nagy, Erzsébet

    2003-01-01

    Several mycoparasitic strains belonging to the filamentous fungal genus Trichoderma are promising candidates for the biological control of plant pathogenic fungi. When planning the application of antagonistic Trichoderma strains for the purposes of biological control, it is very important to consider the environmental parameters affecting the biocontrol agents in the soil. A series of abiotic and biotic environmental parameters has an influence on the biocontrol efficacy of Trichoderma. Some ...

  4. 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.

  5. [Improvement of Trichoderma strains for biocontrol].

    Science.gov (United States)

    Benítez, T; Rey, M; Delgado-Jarana, J; Rincón, A M; Limón, M C

    2000-03-01

    The use of the fungal genus Trichoderma to control fungal plant diseases is a promising alternative to the use of chemical compounds. The aim of this work has been to obtain Trichoderma strains with improved capacity as biological control agents. To do so, the hydrolytic capacity on fungal cell walls of strains of the fungus Trichoderma harzianum has been increased. On one hand, transformation experiments with genes which coded for chitinases and glucanases have been carried out in T. harzianumstra ins. On the other hand, the medium composition has also been modified in order to eliminate proteolytic degradation of some of the overproduced enzymes. Finally, hybrid chitinolytic enzymes with substrate-binding domains have been produced as an alternative to obtain improved biocontrol strains. The transformant strains, when compared with the wild type, showed improved antifungal capacity against the phytopathogenic fungus Rhizoctonia solani, in in vitro experiments. PMID:15762779

  6. 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.; Steenberg, Tove

    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 si...

  7. 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.

  8. 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.

  9. Selective Media for In Vitro Activity Evaluation of Bacterial Biocontrol Against Pathogenic Vibrio

    OpenAIRE

    ALIM ISNANSETYO; MUHTADI; INDAH ISTIQOMAH; KAMISO HANDOYO NITIMULYO; TRIYANTO

    2011-01-01

    In vitro activity test is a critical evaluation to screen the potential biocontrol agent. We developed a selective medium for quantitative in vitro activity evaluation of bacterial biocontrol agents against pathogenic Vibrio in aquaculture. Sensitivity test of bacterial biocontrol and Vibrio spp. to nine antibiotics showed that oxytetracycline inhibited the growth of Vibrio spp., but did not inhibit the growth of the bacterial biocontrol. This selective inhibition activity of oxytetracycline ...

  10. 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.

  11. 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...

  12. History of infection with different male-killing bacteria in the two-spot ladybird beetle Adalia bipunctata revealed through mitochondrial DNA sequence analysis.

    OpenAIRE

    v d Schulenburg, J Hinrich G; Hurst, Gregory D. D.; Tetzlaff, Dagmar; Booth, Gwendolen E; Zakharov, Ilia A; Majerus, Michael E. N.

    2002-01-01

    The two-spot ladybird beetle Adalia bipunctata (Coleoptera: Coccinellidae) is host to four different intracellular maternally inherited bacteria that kill male hosts during embryogenesis: one each of the genus Rickettsia (alpha-Proteobacteria) and Spiroplasma (Mollicutes) and two distinct strains of Wolbachia (alpha-Proteobacteria). The history of infection with these male-killers was explored using host mitochondrial DNA, which is linked with the bacteria due to joint maternal inheritance. T...

  13. 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.

  14. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  16. A role for reactive oxygen species in postharvest biocontrol

    Science.gov (United States)

    Reactive oxygen species (ROS) play an important role in plant defense responses against pathogens. There is evidence that microbial biocontrol agents also induce a transient production of ROS in a host plant which triggers local and systemic defense responses. In this study, we explored the abilit...

  17. Farmer evaluation of biocontrol methods against rootknot nematodes in tomatoes

    OpenAIRE

    McLeod, Anni; Ndungu, Beth; Karanja, Daniel; Karanja, Peter

    2002-01-01

    This report was presented at the UK Organic Research 2002 Conference. Root-knot nematodes in tomatoes cause financial loss to Kenyan smallholders. While soil fumigation appears to be losing effectiveness two bio-control agents (bcas), Pasteuria penetrans and Verticillium chlamydosporium, appear promising. Participatory budgeting is being used to compare the bcas with chemical and other biological controls on commercial and organic smallholdings.

  18. ROLE OF BIOFILMS IN BIOCONTROL OF BOTRYTIS CINEREA

    Science.gov (United States)

    Microorganisms often inhabit the leaf surface in organized structures termed biofilms. Burkholderia sp., FP62 is a biocontrol agent of B. cinerea in geranium and forms extensive biofilms in the phyllosphere. Scanning electron micrographs demonstrate extensive phyllosphere colonization (60-70% of t...

  19. Grouper as a natural biocontrol of invasive lionfish.

    Science.gov (United States)

    Mumby, Peter J; Harborne, Alastair R; Brumbaugh, Daniel R

    2011-01-01

    Lionfish (Pterois volitans/miles) have invaded the majority of the Caribbean region within five years. As voracious predators of native fishes with a broad habitat distribution, lionfish are poised to cause an unprecedented disruption to coral reef diversity and function. Controls of lionfish densities within its native range are poorly understood, but they have been recorded in the stomachs of large-bodied Caribbean groupers. Whether grouper predation of lionfish is sufficient to act as a biocontrol of the invasive species is unknown, but pest biocontrol by predatory fishes has been reported in other ecosystems. Groupers were surveyed along a chain of Bahamian reefs, including one of the region's most successful marine reserves which supports the top one percentile of Caribbean grouper biomass. Lionfish biomass exhibited a 7-fold and non-linear reduction in relation to the biomass of grouper. While Caribbean grouper appear to be a biocontrol of invasive lionfish, the overexploitation of their populations by fishers, means that their median biomass on Caribbean reefs is an order of magnitude less than in our study. Thus, chronic overfishing will probably prevent natural biocontrol of lionfishes in the Caribbean. PMID:21731769

  20. Grouper as a natural biocontrol of invasive lionfish.

    Directory of Open Access Journals (Sweden)

    Peter J Mumby

    Full Text Available Lionfish (Pterois volitans/miles have invaded the majority of the Caribbean region within five years. As voracious predators of native fishes with a broad habitat distribution, lionfish are poised to cause an unprecedented disruption to coral reef diversity and function. Controls of lionfish densities within its native range are poorly understood, but they have been recorded in the stomachs of large-bodied Caribbean groupers. Whether grouper predation of lionfish is sufficient to act as a biocontrol of the invasive species is unknown, but pest biocontrol by predatory fishes has been reported in other ecosystems. Groupers were surveyed along a chain of Bahamian reefs, including one of the region's most successful marine reserves which supports the top one percentile of Caribbean grouper biomass. Lionfish biomass exhibited a 7-fold and non-linear reduction in relation to the biomass of grouper. While Caribbean grouper appear to be a biocontrol of invasive lionfish, the overexploitation of their populations by fishers, means that their median biomass on Caribbean reefs is an order of magnitude less than in our study. Thus, chronic overfishing will probably prevent natural biocontrol of lionfishes in the Caribbean.

  1. 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.

  2. Draft Genome Sequence of a Chitinase-producing Biocontrol Bacterium Serratia sp. C-1

    OpenAIRE

    Seur Kee Park; Young Cheol Kim

    2015-01-01

    The chitinase-producing bacterial strain C-1 is one of the key chitinase-producing biocontrol agents used for effective bioformulations for biological control. These bioformulations are mixed cultures of various chitinolytic bacteria. However, the precise identification, biocontrol activity, and the underlying mechanisms of the strain C-1 have not been investigated so far. Therefore, we evaluated in planta biocontrol efficacies of C-1 and determined the draft genome sequence of the strain in ...

  3. 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.

  4. 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.

  5. Citrus blackfly in Florida: Eradication or bio-control?

    OpenAIRE

    Tefertiller, Kenneth R.; McKee, Vernon C.; Perry, Vernon G.

    1991-01-01

    The citrus blackfly (CBF) invaded south Florida in January 1976. It was considered by scientists to be a major threat to the Florida citrus industry located in the central part of the state. The CBF was successfully contained in a 1000 square mile tri-county quarantined area surrounding Ft. Lauderdale for several months before breaking out to an area near the commercial citrus production area. During this time federal and state research agencies were evaluating a bio-control approach involvin...

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

    OpenAIRE

    MartinJLoessner; StevenHagens

    2014-01-01

    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-...

  7. Responses of Yeast Biocontrol Agents to Environmental Stress

    OpenAIRE

    Sui, Yuan; Wisniewski, Michael; Droby, Samir; Liu, Jia

    2015-01-01

    Biological control of postharvest diseases, utilizing wild species and strains of antagonistic yeast species, is a research topic that has received considerable attention in the literature over the past 30 years. In principle, it represents a promising alternative to chemical fungicides for the management of postharvest decay of fruits, vegetables, and grains. A yeast-based biocontrol system is composed of a tritrophic interaction between a host (commodity), a pathogen, and a yeast species, a...

  8. Novel Routes for Improving Biocontrol Activity of Bacillus Based Bioinoculants

    OpenAIRE

    Wu, Liming; Wu, Hui-Jun; Qiao, Junqing; Gao, XueWen; Borriss, Rainer

    2015-01-01

    Biocontrol (BC) 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 e...

  9. Biocontrol: Bacillus penetrans and Related Parasites of Nematodes

    OpenAIRE

    Sayre, R. M.

    1980-01-01

    Bacillus penetrans Mankau, 1975, previously described as Duboscqia penetrans Thorne 1940, is a candidate agent for biocontrol of nematodes. This review considers the life stages of this bacterium: vegetative growth phase, colony fragmentation, sporogenesis, soil phase, spore attachment, and penetration into larvae of root-knot nematodes. The morphology of the microthallus colonies and the unusual external features of the spore are discussed. Taxonomic affinities with the actinomycetes, partic...

  10. Environmental impact assessment of genetically modified biocontrol agents

    International Nuclear Information System (INIS)

    This review summarises the theoretical basis of risk analysis, and the political and social implications of introducing new biotechnology products in agricultural environments. The main factors to be considered under the present European regulation in the environmental impact assessment of genetically modified biocontrol agents are briefly discussed. Finally, an alternative risk assessment paradigm is proposed for genetically modified microorganisms, which shall consider the intrinsic properties of each antagonist, rather than the method used for generating it

  11. Genome Sequence of the Biocontrol Strain Pseudomonas fluorescens F113

    OpenAIRE

    Redondo-Nieto, M.; M. Barret; Morrisey, J; Germaine, K.; Martínez-Granero, F.; Barahona, E.; Navazo, A.; Sánchez-Contreras, M.; Moynihan, J.; Giddens, S.; Coppoolse, E.; Muriel, C.; Stiekema, W.; Rainey, P; Dowling, D

    2012-01-01

    Pseudomonas fluorescens F113 is a plant growth-promoting rhizobacterium (PGPR) that has biocontrol activity against fungal plant pathogens and is a model for rhizosphere colonization. Here, we present its complete genome sequence, which shows that besides a core genome very similar to those of other strains sequenced within this species, F113 possesses a wide array of genes encoding specialized functions for thriving in the rhizosphere and interacting with eukaryotic organisms.

  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. 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.

  14. 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

  15. The relationship of biofilm production to biocontrol activity of Burkholderia pyrrocinia FP62

    Science.gov (United States)

    Foliar biocontrol agent (BCA) efficacy is often inconsistent due to poor colonization and survival on plant surfaces. Burkholderia pyrrocinia FP62, a superior leaf colonist and BCA of Botrytis cinerea, forms unsaturated biofilms on plant surfaces. To determine the relationship between biocontrol act...

  16. 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.

  17. Yeast microflora of nectarines and their potential for biocontrol of brown rot

    Science.gov (United States)

    Resident fruit microflora has been the source of biocontrol agents for the control of postharvest decays of fruits and the active ingredient in commercialized biocontrol products. With the exception of grapes and apples, information on the resident microflora of other fruits is only fragmentary; ho...

  18. Efficacy of Pseudomonas fluorescens for biocontrol of Escherichia coli 0157:H7 on spinach

    Science.gov (United States)

    Control of foodborne pathogens on leafy green vegetables is crucial for consumer food safety. Biocontrol microbes may inhibit or suppress foodborne pathogen growth and enhance existing post-harvest intervention controls. The efficacy of Pseudomonas fluorescens for biocontrol of Escherichia coli O157...

  19. Draft Genome Sequence of a Chitinase-producing Biocontrol Bacterium Serratia sp. C-1

    Directory of Open Access Journals (Sweden)

    Seur Kee Park

    2015-09-01

    Full Text Available The chitinase-producing bacterial strain C-1 is one of the key chitinase-producing biocontrol agents used for effective bioformulations for biological control. These bioformulations are mixed cultures of various chitinolytic bacteria. However, the precise identification, biocontrol activity, and the underlying mechanisms of the strain C-1 have not been investigated so far. Therefore, we evaluated in planta biocontrol efficacies of C-1 and determined the draft genome sequence of the strain in this study. The bacterial C-1 strain was identified as a novel Serratia sp. by a phylogenic analysis of its 16S rRNA sequence. The Serratia sp. C-1 bacterial cultures showed strong in planta biocontrol efficacies against some major phytopathogenic fungal diseases. The draft genome sequence of Serratia sp. C-1 indicated that the C-1 strain is a novel strain harboring a subset of genes that may be involved in its biocontrol activities.

  20. 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

  1. Biocontrol potential of Trichoderma Sp. against plant pathogens

    Directory of Open Access Journals (Sweden)

    Anand S.

    2009-12-01

    Full Text Available Forty two strains of Trichoderma sp. were isolated from cultivated lands around Bangalore andanalyzed for their antagonistic potential against Sclerotium rolfsii and Fusarium ciceri. The potential ofbiocontrol agents ultimately lies in their capacity to control pathogens in vivo. Bioefficacy studies were henceconducted using chickpea (Cicer argentums c.v. Annigeri as an experimental plant by the roll paper towelmethod. Overall the isolates T40, T35, T30 and T25 showed better antagonistic potential in addition toenhancing plant growth. The production of chitinases to break down the mycelial cell walls of fungal plantpathogens has been implicated as a major cause of biocontrol activity (Inbar and Chet, 1995. In order tostudy the mechanism of biocontrol, ten better performing strains were plated on media, amended withcolloidal chitin and Sclerotium rolfsii cell wall extract. All the isolates showed chitinolytic activity on day threeas well as day five. Production of endochitinase and exochitinase were assayed in liquid media usingcolloidal chitin amended broth. Strains T35 and T6 displayed maximum endochitinase and exochitinaseactivity. Although all strains exhibited cellulase activity, the quantum of enzyme produced was higher in T35and T6. The results also indicate a positive correlation between enzyme production and bioefficacy.

  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. 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.

  4. Effect of fungicides and of biocontrol agents against powdery mildew of turnip.

    Science.gov (United States)

    Gilardi, G; Gullino, M L; Garibaldi, A

    2008-01-01

    The activity of several fungicides and of two biocontrol agents, Bacillus subtilis and Ampelomyces quisqualis, alone and in combination, against Erysiphe cruciferarum, causal agent of powdery mildew, was evaluated on turnip under controlled conditions. Among the tested fungicides, quinoxyfen and azoxystrobin provided the best disease control, followed by penconazole, myclobutanil, dinocap and meptyldinocap. Sulphur provided a only partial control. The two biocontrol agents used alone provided a only partial disease control, with B. subtilis being generally more effective. The mixture B. subtilis + azoxystrobin was very effective and generally more active than the two components applied alone. The possibility of introducing biocontrol agents into IPM is discussed. PMID:19226738

  5. 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-off in...

  6. LACK OF ANTAGONISM BETWEEN THE BIOCONTROL AGENT GLIOCLADIUM VIRENS AND VESICULAR ARBUSCULAR MYCORRHIZAL FUNGI

    Science.gov (United States)

    Fungal biocontrol agent Gliocladium virens Miller, Giddens & Foster on the colonization of cucumber by the VA mycorrhizal fungi Glomus etunicatum Becker & Gerdemann and Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe was investigated. noculum of G. virens grown on wheat bran o...

  7. Trichoderma spp.: a biocontrol agent for sustainable management of plant diseases

    International Nuclear Information System (INIS)

    Trichoderma spp. are mainly asexual fungi that are present in all types of agricultural soils and also in decaying wood. The antagonistic activity of Trichoderma species showed that it is parasitic on many soil-borne and foliage pathogens. The fungus is also a decomposer of cellulosic waste materials. Recent discoveries show that the fungi not only act as biocontrol agents, but also stimulate plant resistance, and plant growth and development resulting in an increase in crop production. The biocontrol activity involving mycoparasitism, antibiotics and competition for nutrients, also induces defence responses or systemic resistance responses in plants. These responses are an important part of Trichoderma in biocontrol program. Currently, Trichoderma spp., is being used to control plant diseases in sustainable diseases management systems. This paper reviews the published information on Trichoderma spp., and its biocontrol activity in sustainable disease management programs. (author)

  8. 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...

  9. 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.

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

    OpenAIRE

    Susanne Zeilinger; Markus Omann

    2007-01-01

    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 pla...

  11. Test of biocontrol products against fungal pathogens of tomato and lettuce

    OpenAIRE

    Lenaerts, Ruben

    2011-01-01

    Chemical control remains the main measure to reduce the incidence of fungal diseases in various fruits and vegetables. A serious problem against the effective use of these chemicals is the development of resistance by the fungi. The exploitation of biocontrol agents, safer to consumers and the environment, is urgently needed. Furthermore, the demand for reduction in the use of pesticides in agriculture and horticulture increases interest in the possibility of the application of biocontrol age...

  12. EFFECT OF BIO-CONTROL AGENTS ON RADIAL GROWTH OF SCLEROTIUM ROLFSII IN VITRO

    OpenAIRE

    G. Darvin; V. Prasanna Kumari

    2013-01-01

    To know the efficacy of bio-control agents on growth of Sclerotium rolfsii causing stem rot of groundnut, an in vitro study was conducted in the Department of Plant Pathology, Agricultural College, Bapatla. For this, three Trichoderma spp., two Pseudomonas fluorescens isolates and one Bacillus subtilis were selected as biocontrol agents. We observed that, there is a significant difference among all the treatments. The lowest radial growth (1.9 cm) and highest per cent inhibition (79.26%) were...

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

    OpenAIRE

    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 is...

  14. Potential Pseudomonas Isolated from Soybean Rhizosphere as Biocontrol against Soilborne Phytopathogenic Fungi

    OpenAIRE

    ANTONIUS SUWANTO; YULIN LESTARI; ARIS TRI WAHYUDI; ARI SUSILOWATI; SURYO WIYONO

    2011-01-01

    Plants are liable to be attacked by soilborne fungal pathogens which are responsible to reduce plant growth and losses in yield. In Indonesia, indigenous soybeans’ rhizobacteria such as antifungal producing Pseudomonas sp. have not many been reported yet. Therefore, the potential of the Pseudomonas sp. as biocontrol agent should be deeply explored. The aim of this study was to screen the indigenous soybeans’ rhizobacteria Pseudomonas sp. that possessing biocontrol characters against soilborne...

  15. Screening criteria for the development of commercial products for biocontrol of plant pathogens

    OpenAIRE

    Köhl, Jurgen; Blum, Bernard; Nicot, Philippe; Ruocco, Michelina

    2012-01-01

    Antagonists for use in commercial biocontrol products have to fulfil many different requirements. Besides being active control agents against the specific targeted plant pathogens, they must be safe and cost effective. The development of new biocontrol products starts with screening programs including hundreds or thousands of candidates. For commercial use, important criteria are market size, efficacy, ecological characteristics, production costs, safety, environmental risks and protection of...

  16. Myco-Biocontrol of Insect Pests: Factors Involved, Mechanism, and Regulation

    OpenAIRE

    Sardul Singh Sandhu; Sharma, Anil K; Vikas Beniwal; Gunjan Goel; Priya Batra; Anil Kumar; Sundeep Jaglan; Sharma, A K; Sonal Malhotra

    2012-01-01

    The growing demand for reducing chemical inputs in agriculture and increased resistance to insecticides have provided great impetus to the development of alternative forms of insect-pest control. Myco-biocontrol offers an attractive alternative to the use of chemical pesticides. Myco-biocontrol agents are naturally occurring organisms which are perceived as less damaging to the environment. Their mode of action appears little complex which makes it highly unlikely that resistance could be dev...

  17. Plant pathogens as biocontrol agents of Cirsium arvense – an overestimated approach?

    OpenAIRE

    Esther Müller; Wolfgang Nentwig

    2011-01-01

    Cirsium arvense is one of the worst weeds in agriculture. As herbicides are not very effective and not accepted by organic farming and special habitats, possible biocontrol agents have been investigated since many decades. In particular plant pathogens of C. arvense have received considerable interest and have been promoted as “mycoherbicides” or “bioherbicides”. A total of 10 fungi and one bacterium have been proposed and tested as biocontrol agents against C. arvense...

  18. Facilitating the registration of biocontrol organisms, plant extracts and semiochemicals in Europe

    OpenAIRE

    Speiser, B.; Tamm, L.; Bale, J.; Fjelsted, A.; Hokkanen, H; Menzler-Hokkanen, I; Kuhlmann, U.; Strasser, H; Hauschild, R.; Strauch, O.; Ehlers, R.U.

    2008-01-01

    The legal regulation of plant protection products (Dir. 91/414/ EEC) is a bottleneck in the market introduction of new microbial biocontrol agents, plant extracts and pheromones. In contrast, invertebrate biocontrol agents (“beneficials”) are not registered at EU level. The EU-funded project REBECA suggested improvements to accelerate the regulation process and make it more cost-effective, without compromises to the level of safety. Representatives of all stakeholder groups participated in...

  19. Relationship between the aggressiveness of Botrytis cinerea on tomato and the efficacy of biocontrol

    OpenAIRE

    Bardin, Marc; Comby, Morgane; Troulet, Claire; Nicot, Philippe

    2013-01-01

    The development of BCAs represents an attractive alternative to fungicides for the protection of crops against plant pathogens but the durability of this method has not been studied in details. The objective of the present work was to estimate the risk of loss of biocontrol efficacy towards Botrytis cinerea, by evaluating the sensibility of various isolates of the pathogen to the biocontrol agent Microdochium dimerum. The protective efficacy of M. dimerum was evaluated on tomato plants agains...

  20. Potential biocontrol of fumonisin b1 production by fusarium verticillioides under different ecophysiological conditions in maize

    OpenAIRE

    Samsudin, Nik Iskandar Putra Bin

    2015-01-01

    Fusarium verticillioides contaminates maize with the fumonisin group of mycotoxins for which there are strict legislative limits in many countries including the EU. The objectives of this project were (a) to examine the microbial diversity of maize samples from different regions and isolate potential biocontrol agents which could antagonize F. verticillioides and reduce fumonisin B1 (FB1) production, (b) to screen the potential biocontrol candidates using antagonistic interacti...

  1. 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. PMID:26845376

  2. Biocontrol of larval mosquitoes by Acilius sulcatus (Coleoptera: Dytiscidae

    Directory of Open Access Journals (Sweden)

    Banerjee Siddhartha S

    2008-10-01

    Full Text Available Abstract Background Problems associated with resistant mosquitoes and the effects on non-target species by chemicals, evoke a reason to find alternative methods to control mosquitoes, like the use of natural predators. In this regard, aquatic coleopterans have been explored less compared to other insect predators. In the present study, an evaluation of the role of the larvae of Acilius sulcatus Linnaeus 1758 (Coleoptera: Dytiscidae as predator of mosquito immatures was made in the laboratory. Its efficacy under field condition was also determined to emphasize its potential as bio-control agent of mosquitoes. Methods In the laboratory, the predation potential of the larvae of A. sulcatus was assessed using the larvae of Culex quinquefasciatus Say 1823 (Diptera: Culicidae as prey at varying predator and prey densities and available space. Under field conditions, the effectiveness of the larvae of A. sulcatus was evaluated through augmentative release in ten cemented tanks hosting immatures of different mosquito species at varying density. The dip density changes in the mosquito immatures were used as indicator for the effectiveness of A. sulcatus larvae. Results A single larva of A. sulcatus consumed on an average 34 IV instar larvae of Cx. quinquefasciatus in a 24 h period. It was observed that feeding rate of A. sulcatus did not differ between the light-on (6 a.m. – 6 p.m., and dark (6 p.m. – 6 a.m. phases, but decreased with the volume of water i.e., space availability. The prey consumption of the larvae of A. sulcatus differed significantly (P A. sulcatus larvae, while with the withdrawal, a significant increase (p A. sulcatus in regulating mosquito immatures. In the control tanks, mean larval density did not differ (p > 0.05 throughout the study period. Conclusion the larvae of the dytiscid beetle A. sulcatus proved to be an efficient predator of mosquito immatures and may be useful in biocontrol of medically important mosquitoes.

  3. GENETIC DIVERSITY OF POTENTIAL BIOCONTROL AGENTS AGAINST COLLECTOTRICHUM GLOEOSPORIOIDES CAUSING MANGO ANTHRACNOSE AGAINST COLLECTOTRICHUM GLOEOSPORIOIDES CAUSING MANGO ANTHRACNOSE

    OpenAIRE

    NAGALAKSHMI DEVAMMA M; J. Patricia Rajkumari; P. Suvarnalatha Devi

    2014-01-01

    The antagonistic potential biocontrol agents was evaluated against the isolate PTR6 since it was found to be highly virulent based on the results obtained in pathogenic variability test. The antagonistic effect of native microflora was assessed based on their ability to inhibit the pathogen growth in dual culture technique. Among the 21 bacterial biocontrol agents, the antagonist BP6 and BL5 completely (100%) inhibited growth of the pathogen. Among the 21Trichoderma biocontrol...

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

    OpenAIRE

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

    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...

  5. 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

    International Nuclear Information System (INIS)

    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.

  6. 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.

  7. 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 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. PMID:25288942

  8. 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

    2016-01-01

    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. PMID:26497457

  9. 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

    2016-01-01

    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. PMID:27147933

  10. 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.

  11. 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. PMID:27147933

  12. Draft Genome Sequence of a Biocontrol Rhizobacterium, Chryseobacterium kwangjuense Strain KJ1R5, Isolated from Pepper (Capsicum annuum).

    Science.gov (United States)

    Jeong, Jin-Ju; Park, Hongjae; Park, Byeong Hyeok; Mannaa, Mohamed; Sang, Mee Kyung; Choi, In-Geol; Kim, Ki Deok

    2016-01-01

    Strain KJ1R5 of the rhizobacterium ITALIC! Chryseobacterium kwangjuenseis an effective biocontrol agent against Phytophthora blight of pepper caused by a destructive soilborne oomycete, ITALIC! Phytophthora capsici Here, we present the draft genome sequence of strain KJ1R5, which contains genes related to biocontrol, plant growth promotion, and environmental stress adaptation. PMID:27103726

  13. 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...

  14. Draft Genome Sequence of a Biocontrol Rhizobacterium, Chryseobacterium kwangjuense Strain KJ1R5, Isolated from Pepper (Capsicum annuum)

    Science.gov (United States)

    Jeong, Jin-Ju; Park, Hongjae; Park, Byeong Hyeok; Mannaa, Mohamed; Sang, Mee Kyung

    2016-01-01

    Strain KJ1R5 of the rhizobacterium Chryseobacterium kwangjuense is an effective biocontrol agent against Phytophthora blight of pepper caused by a destructive soilborne oomycete, Phytophthora capsici. Here, we present the draft genome sequence of strain KJ1R5, which contains genes related to biocontrol, plant growth promotion, and environmental stress adaptation. PMID:27103726

  15. Trichoderma harzianum: a biocontrol agent against Bipolaris oryzae.

    Science.gov (United States)

    Abdel-Fattah, Gamal M; Shabana, Yasser M; Ismail, Adel E; Rashad, Younes Mohamed

    2007-08-01

    Rice brown spot, caused by Bipolaris oryzae, can be a serious disease causing a considerable yield loss. Trichoderma harzianum is an effective biocontrol agent for a number of plant fungal diseases. Thus, this research was carried out to investigate the mechanisms of action by which T. harzianum antagonizes Bipolaris oryzae in vitro, and the efficacy of spray application of a spore suspension of T. harzianum for control of rice brown spot disease under field conditions. In vitro, the antagonistic behavior of T. harzianum resulted in the overgrowth of B. oryzae by T. harzianum, while the antifungal metabolites of T. harzianum completely prevented the linear growth of B. oryzae. Light and scanning electron microscope (SEM) observations showed no evidence that mycoparasitism contributed to the aggressive nature of the tested isolate of T. harzianum against B. oryzae. Under field conditions, spraying of a spore suspension of T. harzianum at 10(8)spore ml(-1) significantly reduced the disease severity (DS) and disease incidence (DI) on the plant leaves, and also significantly increased the grain yield, total grain carbohydrate, and protein, and led to a significant increase in the total photosynthetic pigments (chlorophyll a and b and carotenoids) in rice leaves. PMID:17592758

  16. 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.

  17. Insight into tick biocontrol with special regard to fungi.

    Science.gov (United States)

    Lonc, Elżbieta; Guz-Regner, Katarzyna; Kiewra, Dorota; Szczepańska, Anna

    2014-01-01

    The epidemiological and epizootic importance of ticks has been known for a few decades since of the discovery of their role as vectors of many new diseases, and the better detection of those already known. Given the durability of chemical preparations in the environment and the increasing problem of developing tick resistance, natural strategies for biological control are sought. A promising alternative to chemical pesticides is the use of entomopathogenic organisms for effective integrated pest management of low environmental impact. A number of promising microbes have been identified during the search for effective means of controlling the tick population, but the knowledge about the impact of these pathogens on the environment and other non-target organisms is still insufficient. Previous research has still not provided a definite answer about the safety of their use. It is known, however,that the chemicals which are currently used have a negative impact on the environment and/or cause resistance. No efficient biocompound has yet been devised for commercial use. Potential microorganisms for tick biocontrol (mainly bacteria and fungi) are natural tick pathogens, living in the same environment. With their adhesive properties, and their ability to digest the cuticle, they may constitute an appropriate ingredient of bioacaricides. Until now, fungal insecticides have been used only to control crop pests. PMID:25281814

  18. 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.

  19. 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.

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

    Science.gov (United States)

    Ginsberg, Howard S.

    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.

  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

    2016-01-01

    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. PMID:26984671

  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

    OpenAIRE

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

    2014-01-01

    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....

  3. 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. PMID:25320450

  4. The Development and Use of Microbial Biocontrol Agents for Agricultural Pests

    Science.gov (United States)

    The idea of using microbial pathogens of agronomic pests as a method of biological control dates back to the 19th century. Two approaches to biological control have been employed: the “classical” and the “inundative” approach. The classical approach to biocontrol is generally practiced on public o...

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

    Science.gov (United States)

    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 ...

  6. COMPARATIVE ASSESSMENT OF MOSQUITO BIOCONTROL EFFICIENCY BETWEEN GUPPY (POECILIA RETICULATA AND PANCHAX MINNOW (APLOCHEILUS PANCHAX

    Directory of Open Access Journals (Sweden)

    Sandipan Gupta and Samir Banerjee

    2013-01-01

    Full Text Available The present work was designed to compare the mosquito biocontrol efficiency of guppy and panchax minnow, the two popular fish species which so far have been used for mosquito biocontrol here in India. Study of the predation efficiency in relation to fish size and larval size has revealed significant better predation efficiency of panchax minnow over guppy in all size groups except for pupae in small size group fishes. Study of the comparative predation efficiency under vegetative cover has revealed significant (P<0.01 higher predation efficiency for panchax minnow over guppy. Study of the comparative predation efficiency under different depth of water has revealed superior predation efficiency of guppy under shallow water depth whereas panchax minnow has shown significantly better predation efficiency with increasing water depth. So, panchax minnow is a better mosquito biocontrol agent in waterbodies with vegetative covering and in comparatively deep water bodies whereas guppy can be used for mosquito control in very shallow water depth. But overall the study has depicted the superiority of panchax minnow over guppy as mosquito biocontrol agent.

  7. SELECTING FUNGAL BIOCONTROL AGENTS AMENABLE TO PRODUCTION BY LIQUID CULTURE FERMENTATION

    Science.gov (United States)

    Numerous fungi show excellent potential for use as biocontrol agents due to their ability to selectively infect and kill a variety of weedy and insect pests or their ability to antagonize or exclude plant disease-causing organisms through parasitism or competitive exclusion. The lack of suitable me...

  8. 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

  9. 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...

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

    International Nuclear Information System (INIS)

    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)

  11. 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)

  12. Incorporating Ecologically Relevant Measures of Pesticide Effect for Estimating the Compatibility of Pesticides and Biocontrol Agents

    Science.gov (United States)

    The compatibility of biological control agents with pesticides is a central concern in integrated pest management programs. The most common assessments of compatibility consist of simple comparisons of acute toxicity among pest species and select biocontrol agents. A more sophisticated approach, d...

  13. Draft Genome Sequences of the Pseudomonas fluorescens Biocontrol Strains Wayne1R and Wood1R

    OpenAIRE

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

    2012-01-01

    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.

  14. 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. PMID:26637302

  15. Assessment of biocontrol strains for reduction of mycotoxins (aflatoxin and CPA) in maize

    Science.gov (United States)

    Aspergillus flavus strains K49, NRRL 21882 (from Afla-Guard®) and AF36 are being developed as biocontrol agents for the control of aflatoxin in maize. In this study, the three non-aflatoxigenic strains were compared to evaluate which is most effective in reducing aflatoxin. Also, we tested these st...

  16. 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...

  17. 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…

  18. Draft Genome Sequence of the Commercial Biocontrol Strain Pantoea agglomerans P10c.

    Science.gov (United States)

    Smits, Theo H M; Rezzonico, Fabio; Blom, Jochen; Goesmann, Alexander; Abelli, Azzurra; Kron Morelli, Roberto; Vanneste, Joël L; Duffy, Brion

    2015-01-01

    We report here the draft genome sequence of the biocontrol strain Pantoea agglomerans P10c, composed of a draft chromosome and two plasmids: the 559-kb large Pantoea plasmid 1 (pPag3) and a 182-kb plasmid (pPag1). A genomic island containing pantocin A biosynthesis genes was identified. PMID:26659685

  19. Draft Genome Sequence of the Commercial Biocontrol Strain Pantoea agglomerans P10c

    OpenAIRE

    Smits, Theo H. M.; Rezzonico, Fabio; Blom, Jochen; Goesmann, Alexander; Abelli, Azzurra; Kron Morelli, Roberto; Vanneste, Joël L.; Duffy, Brion

    2015-01-01

    We report here the draft genome sequence of the biocontrol strain Pantoea agglomerans P10c, composed of a draft chromosome and two plasmids: the 559-kb large Pantoea plasmid 1 (pPag3) and a 182-kb plasmid (pPag1). A genomic island containing pantocin A biosynthesis genes was identified.

  20. 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. PMID:26774866

  1. 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. PMID:27199931

  2. 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.

  3. 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. PMID:20206395

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

    OpenAIRE

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

    2011-01-01

    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 gnoto...

  5. Improvement of the Fungal Biocontrol Agent Trichoderma atroviride To Enhance both Antagonism and Induction of Plant Systemic Disease Resistance

    OpenAIRE

    Brunner, Kurt; Zeilinger, Susanne; Ciliento, Rosalia; Woo, Sheridian L.; Lorito, Matteo; Kubicek, Christian P; Mach, Robert L.

    2005-01-01

    Biocontrol agents generally do not perform well enough under field conditions to compete with chemical fungicides. We determined whether transgenic strain SJ3-4 of Trichoderma atroviride, which expresses the Aspergillus niger glucose oxidase-encoding gene, goxA, under a homologous chitinase (nag1) promoter had increased capabilities as a fungal biocontrol agent. The transgenic strain differed only slightly from the wild-type in sporulation or the growth rate. goxA expression occurred immediat...

  6. Effect of nitrogen fertilisation of strawberry plants on the efficacy of defence-stimulating biocontrol products against Botrytis cinerea

    OpenAIRE

    Nicot, Philippe; Bardin, Marc; Debruyne, François; Duffaud, Magali; Lecompte, François; Neu, Laurent; Pascal, Michel

    2013-01-01

    Although Nitrogen (N) is a key component in many compounds implicated in host-pathogen interactions, little is known on the possible effect of N fertilisation of the plant on the efficacy of defence-stimulating biocontrol agents. In the present work we examined the effect of five levels of N nutrition on the susceptibility of strawberry leaves to Botrytis cinerea and on the protective efficacy of two biocontrol products presumed to induce plant defence mechanisms. Two days after the app...

  7. Combinations of Biocontrol Agents for Management of Plant-Parasitic Nematodes and Soilborne Plant-Pathogenic Fungi

    OpenAIRE

    Meyer, Susan L. F.; Roberts, Daniel P.

    2002-01-01

    Numerous microbes are antagonistic to plant-parasitic nematodes and soilborne plant-pathogenic fungi, but few of these organisms are commercially available for management of these pathogens. Inconsistent performance of applied biocontrol agents has proven to be a primary obstacle to the development of successful commercial products. One of the strategies for overcoming inconsistent performance is to combine the disease-suppressive activity of two (or more) beneficial microbes in a biocontrol ...

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

    OpenAIRE

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

    2013-01-01

    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 penetra...

  9. Augmentative Biocontrol in Natural Marine Habitats: Persistence, Spread and Non-Target Effects of the Sea Urchin Evechinus chloroticus

    OpenAIRE

    Javier Atalah; 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 Fiord...

  10. Influence of Commercial Antibiotics on Biocontrol of Soft Rot and Plant Growth Promotion in Chinese Cabbages by Bacillus vallismortis EXTN-1 and BS07M

    OpenAIRE

    Mee Kyung Sang; Swarnalee Dutta; Kyungseok Park

    2015-01-01

    We investigated influence of three commercial antibiotics viz., oxolinic acid, streptomycin, and validamycin A, on biocontrol and plant growth promoting activities of Bacillus vallismortis EXTN-1 and BS07M in Chinese cabbage. Plants were pre-drenched with these strains followed by antibiotics application at recommended and ten-fold diluted concentration to test the effect on biocontrol ability against soft rot caused by Pectobacterium carotovorum SCC1. The viability of the two biocontrol stra...

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

    OpenAIRE

    Wanessa Altimiras Costa; Maria Cristina Dantas Vanetti; Rolf Puschamann

    2009-01-01

    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...

  12. Antagonismo direto e biocontrole da podridão-mole-do-tomateiro pelo uso de procariotas Direct antagonism and biocontrol of tomato soft rot using prokaryotes

    OpenAIRE

    Victor Rafael Barra; Reginaldo da Silva Romeiro; Flávio Augusto de Oliveira Garcia; Andréa Bittencourt Moura; Harllen Sandro Alves Silva; Henrique Lopes Mendonça; Bernardo de Almeida Halfeld-Vieira

    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. ...

  13. 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 ).

  14. 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. PMID:25976334

  15. Bio-prospecting of distillery yeasts as bio-control and bio-remediation agents.

    Science.gov (United States)

    Ubeda, Juan F; Maldonado, María; Briones, Ana I; Francisco, J Fernández; González, Francisco J

    2014-05-01

    This work constitutes a preliminary study in which the capacity of non-Saccharomyces yeasts isolated from ancient distilleries as bio-control agents against moulds and in the treatment of waste waters contaminated by heavy metals-i.e. bio-remediation-is shown. In the first control assays, antagonist effect between non-Saccharomyces yeasts, their extracts and supernatants against some moulds, analysing the plausible (not exhaustive) involved factors were qualitatively verified. In addition, two enzymatic degrading properties of cell wall plant polymers, quitinolitic and pectinolitic, were screened. Finally, their use as agents of bio-remediation of three heavy metals (cadmium, chromium and lead) was analysed semi-quantitatively. The results showed that all isolates belonging to Pichia species effectively inhibited all moulds assayed. Moreover, P. kudriavzevii is a good candidate for both bio-control and bio-remediation because it inhibited moulds and accumulated the major proportion of the three tested metals. PMID:24370629

  16. EFFICACY OF BIOCONTROL AGENTS IN CONTROLLING RHIZOCTONIA SOLANI ON NAGA KING CHILLI ( Capsicum chinense Jacq.)

    OpenAIRE

    Marinus Ngullie; Loli Daiho

    2013-01-01

    Available biocontrol agents were evaluated either alone or in various combinations for finding out their efficacy in suppressing Rhizoctonia seedling rot incidence and promoting plant growth of Naga king chilli (Capsicum chinense Jacq.) in green house as well field conditions. Among all tested combination, the treatment containing combination of T. viride +P. fluorescens was found most effective in reducing the incidence of seedling rot in both greenhouse and field condition. Highest pe...

  17. 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.

  18. Method To Enhance Growth and Sporulation of Pelletized Biocontrol Fungi †

    OpenAIRE

    Knudsen, G R; Eschen, D. J.; Dandurand, L. M.; Wang, Z. G.

    1991-01-01

    The biocontrol fungi Trichoderma harzianum, used to control soilborne plant pathogens, and Beauveria bassiana, used to control insect pests, were formulated as mycelial biomass in alginate pellets with wheat bran added. After drying for 0, 4, or 16 h, pellets were placed in water or in aqueous solutions of polyethylene glycol (PEG) 8000 for 4 to 24 h and then allowed to continue drying. PEG-treated pellets containing T. harzianum showed significantly greater proliferation of hyphae in soil th...

  19. Ecology of Anti-Biofilm Agents II: Bacteriophage Exploitation and Biocontrol of Biofilm Bacteria

    OpenAIRE

    Stephen T. Abedon

    2015-01-01

    Bacteriophages are the viruses of bacteria. In the guise of phage therapy they have been used for decades to successfully treat what are probable biofilm-containing chronic bacterial infections. More recently, phage treatment or biocontrol of biofilm bacteria has been brought back to the laboratory for more rigorous assessment as well as towards the use of phages to combat environmental biofilms, ones other than those directly associated with bacterial infections. Considered in a companion ar...

  20. Viunalikeviruses are environmentally common agents of horizontal gene transfer in pathogens and biocontrol bacteria

    OpenAIRE

    Matilla, M. A.; Fang, X.; Salmond, George P. C.

    2014-01-01

    Bacteriophages have been used as natural biocontrol and therapeutic agents, but also as biotechnological tools for bacterial engineering. We showed recently that the transducing bacteriophage ϕMAM1 is a ViI-like phage and a member of the new genus, ‘Viunalikevirus'. Here, we show that four additional ViI-like phages and three new environmentally isolated viunalikeviruses, all infecting plant and human pathogens, are very efficient generalised transducers capable of transducing chromosomal mar...

  1. Plant growth-promoting rhizobacteria (PGPR): Their potential as antagonists and biocontrol agents

    OpenAIRE

    Anelise Beneduzi; Adriana Ambrosini; Luciana M.P. Passaglia

    2012-01-01

    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 growt...

  2. 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.

  3. Ecophysiological approaches to production and formulation of the biocontrol yeast Pichia anomala

    OpenAIRE

    Mokiou, Stella

    2004-01-01

    To produce commercial biocontrol agents (BCAs) successfully, it is important that cheap and economic substrates are used which support high numbers of good quality inoculum. Production of formulations conserving ecological competence and shelf-life should also be ensured. With this in mind, studies focusing on yeast ecophysiology were conducted to produce and formulate ecologically competent P. anomala cells for controlling spoilage of moist cereal grain. The liquid culture systems used were ...

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

    OpenAIRE

    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 ...

  5. Selection of Yeasts Antagonists as Biocontrol Agent of Mango Fruit Rot caused by Botryodiplodia theobromae

    OpenAIRE

    DWI SUGIPRIHATINI; SURYO WIYONO; WIDODO

    2011-01-01

    Fruit rot caused by Botryodiplodia theobromae is one of the most important post harvest disease of mango in Indonesia. Study on biological control on the disease is required to develop environmentally-sound control technology. The research objectives were to study the potency of yeasts in controlling post harvest mango disease i.e. fruit rot caused by B. theobromae and mechanism involve in the biocontrol. Total yeast isolates used for screening were twenty one, four from collection of Plant ...

  6. Rhizospheric bacteria of maize with potential for biocontrol of Fusarium verticillioides

    OpenAIRE

    Figueroa-López, Alejandro Miguel; Cordero-Ramírez, Jesús Damián; Martínez-Álvarez, Juan Carlos; López-Meyer, Melina; Lizárraga-Sánchez, Glenda Judith; Félix-Gastélum, Rubén; Castro-Martínez, Claudia; Maldonado-Mendoza, Ignacio Eduardo

    2016-01-01

    The stalk, ear and root rot (SERR) of maize caused by Fusarium verticillioides (Fv) severely impacts crop production in tropical and subtropical regions. The aim of the present work was to screen bacterial isolates in order to find novel native biocontrol agents against Fv. A culturable bacterial collection consisting of 11,520 isolates enriched in Firmicutes and Proteobacteria was created from rhizosphere samples taken from SERR symptomatic or asymptomatic maize plants. The complete collecti...

  7. Lactic acid bacteria from fresh fruit and vegetables as biocontrol agents of phytopathogenic bacteria and fungi

    OpenAIRE

    Trias Mansilla, Rosalia; Bañeras Vives, Lluís; Montesinos Seguí, Emilio; Badosa Romañó, Esther

    2008-01-01

    This study evaluated the efficacy of lactic acid bacteria (LAB) isolated from fresh fruits and vegetables as biocontrol agents against the phytopathogenic and spoilage bacteria and fungi, Xanthomonas campestris, Erwinia carotovora, Penicillium expansum, Monilinia laxa, and Botrytis cinerea. The antagonistic activity of 496 LAB strains was tested in vitro and all tested microorganisms except P. expansum were inhibited by at least one isolate. The 496 isolates were also analyzed for the inhibit...

  8. What Magnitude Are Observed Non-Target Impacts from Weed Biocontrol?

    OpenAIRE

    David Maxwell Suckling; René François Henri Sforza

    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 (>9...

  9. Enhancement of biocontrol efficacy against Botrytis cinerea through the manipulation of nitrogen fertilization of tomato plants

    OpenAIRE

    Abro, Manzoor Ali; Lecompte, François; Bardin, Marc; Duffaud, Magali

    2013-01-01

    Although nitrogen fertilization is known to affect plant susceptibility to certain pathogens, little is known on its possible effect on the efficacy of biological control. In the present study we examined the effect of five levels of NO3- nutrition on the efficacy of two biocontrol agents (Trichoderma harzianum and Microdochium dimerum) to protect pruning wounds of tomato against Botrytis cinerea. Plants were grown for two months in a greenhouse with a soil-less drip-irrigationsystem. Differe...

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

    OpenAIRE

    Olabiyi, T.I.; Ruocco, M.; Lanzuize, S.

    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...

  11. Biocontrol of sheath blight by Trichoderma asperellum in tropical lowland rice

    OpenAIRE

    de França, Suenny Kelly Santos; Cardoso, Aline Figueiredo; Lustosa, Denise Castro; Ramos, Edson Marcos Leal Soares; de Filippi, Marta Cristina Corsi; da Silva, Gisele Barata

    2015-01-01

    Crop damage by rice sheath blight, Rhizoctonia solani, can decrease rice yield by up to 45 %. The classical control method of rice sheath blight in the Amazon region is the application of fungicides. Therefore, we tested here the efficiency of a biocontrol agent, Trichoderma asperellum, and fungicides. Two experiments of rice cultivation were carried out with seven treatments: four isolates of T. asperellum, a mixture of the four isolates, the fungicide pencycuron, and the control. The first ...

  12. Cucumber Rhizosphere Microbial Community Response to Biocontrol Agent Bacillus subtilis B068150

    OpenAIRE

    Lihua Li; Jincai Ma; A. Mark Ibekwe; Qi Wang; Ching-Hong Yang

    2015-01-01

    Gram-positive bacteria Bacillus subtilis B068150 has been used as a biocontrol agent against the pathogen Fusarium oxysporum cucumerinum. Cucumber was grown in three soils with strain B068150 inoculated in a greenhouse for 90 days, and the colonization ability of strain B068150 in cucumber rhizosphere and non-rhizosphere soils was determined. Changes in total bacteria and fungi community composition and structures using denaturing gradient gel electrophoresis (DGGE) and sequencing were determ...

  13. 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. PMID:26880001

  14. Use of Biocontrol Fungi with Carbofuran in the Control Of Root Knot Nematodes in Okra

    Directory of Open Access Journals (Sweden)

    M. J. Zaki

    1998-01-01

    Full Text Available Use of biocontrol fungi viz, Verticillium chlamydosporium, Paecilomyces lilacinus and Talaromyces flavus alone or mixed with carbofuran significantly (P<0.05 reduced root knot indices on okra plants as compared to control. Maximum reduction in glass formation was observed in the treatments where carbofuran was used either with V. chlamydosporium or P. lilacinus. Greater increase in fresh weight of shoot was observed where P. lilacinus was used with carbofuran followed by the use of P. lilacinus alone.

  15. Is it possible to improve biocontrol agents to practical applications? the pantoea agglomerans CPA-2 example

    OpenAIRE

    Teixidó, Neus; Cañamás, Teresa Paula; Torres, Rosario; Usall, Josep; Viñas, Inma

    2010-01-01

    A major hurdle in exploitation of biocontrol agents is the limited tolerance of fluctuating environmental conditions practically and the difficulties in developing a shelf-stable formulated product as effective as fresh cells. Most of microorganisms are very sensitive to drying processes involved in formulation and biological control is usually limited by the narrow range of conditions below microorganisms are able to survive, establish and effectively control pests and diseases. ...

  16. Biocontrol Activity of Myxococcus sp. KYC 1126 against Phytophthora Blight on Hot Pepper

    OpenAIRE

    Sung Chul Yun; Sung Taek Kim

    2011-01-01

    Bacteriolytic myxobacteria have been known to secrete various antifungal metabolites against several soilborne phytopathogens including Phytophthora. Among the three isolates of Myxococcus spp., KYC 1126 and KYC 1136 perfectly inhibited the mycelial growth of Phytophtora capsici in vitro. In order to show the biocontrol activity on Phytophthora blight of hot pepper, we tried to find the best way of application of myxobacterial isolate. Although KYC 1126 fruiting body was easily grown on the c...

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

    Directory of Open Access Journals (Sweden)

    Abbas Soleimani-Delfan

    2015-09-01

    Full Text Available 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.

  18. 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. PMID:26413062

  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. PMID:25462935

  20. Antagonismo direto e biocontrole da podridão-mole-do-tomateiro pelo uso de procariotas Direct antagonism and biocontrol of tomato soft rot using prokaryotes

    Directory of Open Access Journals (Sweden)

    Victor Rafael Barra

    2009-03-01

    Full Text Available 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. carotovorum com OD540 de 0,45 e 0,65. Os antagonistas UFV-0005, UFV-043, UFV-BF112 e UFV-0006 foram eficientes em proteger plantas de tomateiro contra a podridão-mole.This work aimed to evaluate prokaryotes to provide direct antagonism and biocontrol of tomato soft rot (Pectobacterium carotovorum subsp. carotovorum. Forty-five bacterial isolates previously selected for biological control of several tomato (Lycopersicon esculentum Mill. diseases were evaluated using an antibiosis test. 'Santa Clara' tomato seeds were inoculated with potential antagonist isolates and transplanted to a soil infested with the pathogen, in two asseys, at a propagule concentration of OD540 0.45 and 0.65. Antagonists UFV-0005, UFV-043, UFV-BF112, and UFV-0006 protected tomato plants against soft rot disease.

  1. 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

  2. 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

  3. Effects of autumn kaolin, pyrethrin, and ladybird larvae (Adalia bipunctata) applications on the spring populations of the rosy apple aphid (Dysaphis plantaginea) in an experimental apple orchard (cv. Glockenapfel)

    OpenAIRE

    Wyss, Eric; Daniel, Claudia

    2003-01-01

    Effects of different strategies (insecticide treatment, physical barrier, biocontrol) to control autumn forms of Dysaphis plantaginea. Question 1: Efficacy of pyrethrum, kaolin, and larvae of A. bipunctata to control Dysaphis plantaginea. Question 2: Date of application and number of applications for a valuable efficacy.

  4. Effects of autumn kaolin, pyrethrin, and ladybird larvae (Adalia bipunctata) applications on the spring populations of the rosy apple aphid (Dysaphis plantaginea) in an on-farm apple orchard (cv. Topaz)

    OpenAIRE

    Wyss, Eric; Daniel, Claudia

    2003-01-01

    Effects of different strategies (insecticide treatment, physical barrier, biocontrol) to control autumn forms of Dysaphis plantaginea. Question 1: Efficacy of pyrethrum, kaolin, and larvae of A. bipunctata to control Dysaphis plantaginea. Question 2: Date of application and number of applications for a valuable efficacy.

  5. 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...

  6. 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. PMID:21739253

  7. Biocontrol of Soil Fungi in Tomato with Microencapsulates Containing Bacillus subtilis

    Directory of Open Access Journals (Sweden)

    Marcela H. Suarez

    2011-01-01

    Full Text Available Problem statement: An option to reduce pollution by synthetic agro-chemical in root plant disease management is the use of antagonist rhizobacteria belonging to Bacillus genus, because their inhibitory properties, stimulation of plant growth and crop yield increase. Approach: This study was carried out in order to evaluate if Bacillus subtilis strains could play an antagonists role of plant pathogens and if they can be microencapsulated inside a biopolymer matrix. It was adapted an equipment and evaluated a technique for microcapsules elaboration, in order to incorporate B. subtilis strains and to analyze their potential as biocontrol agents by determining their antagonistic effect against pathogenic soil fungi; in addition, it was analyzed their effect on tomato plant growth promotion under greenhouse conditions. B. subtilis strains identified as B1, J1, M2 and their mixture were used; microcapsules containing bacterial strains were inoculated to tomato seeds cv. Floradade. When seedlings emerged, a second application of microcapsules containing B. subtilis was performed on the pots, which previously were inoculated with the fungi Rhizoctonia solani and Fusarium oxysporum. Response variables were: Incidence and disease severity, plant growth, aerial and root dry weight, leaf area and fruit yield. Results: The outcome showed that the equipment designed and adapted for microcapsules elaboration was useful to obtain microcapsules containing the bacterial strains. B. subtilis strains exerted apparent biocontrol, since incidence and disease severity was reduced and for that reason inhibited the infective activity of the inoculated plant pathogens, also microcapsules containing Bacillus strains stimulated tomato growth and fruit yield. Conclusion: Microcapsules containing B. subtilis strains could be effective biocontrol agents against soil fungi plant pathogens and could have a potential biofertilizer effect, since they stimulated growth and yield

  8. 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.

  9. 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. PMID:20121037

  10. Mathematical models and stabilizing bio-control mechanisms for microbial populations in a cultured environment

    International Nuclear Information System (INIS)

    In this paper we have analyzed a limited nutrient-consumer dynamic model involving distributed time delays both in material recycling and growth response of consumer. It is established that the system exhibits instability characteristics due to the presence of time delays. Three different types of naturally feasible bio-control mechanisms are proposed. It is established that these mechanisms have a stabilizing effect on the system in their own respect. Several independent sets of sufficient conditions for the global asymptotic stability are obtained in each case. Examples and simulations are provided for a clear understanding of the results

  11. 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

  12. 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.

  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. Diversity, biocontrol, and plant growth promoting abilities of xylem residing bacteria from solanaceous crops.

    Science.gov (United States)

    Achari, Gauri A; Ramesh, Raman

    2014-01-01

    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. PMID:24963298

  15. Potential Bio-Control Agent from Rhodomyrtus tomentosa against Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Grace Fiyinfoluwa Odedina

    2015-09-01

    Full Text Available Listeria monocytogenes is an important foodborne pathogen implicated in many outbreaks of listeriosis. This study aimed at screening for the potential use of Rhodomyrtus tomentosa ethanolic leaf extract as a bio-control agent against L. monocytogenes. Twenty-two L. monocytogenes isolates were checked with 16 commercial antibiotics and isolates displayed resistance to 10 antibiotics. All the tested isolates were sensitive to the extract with inhibition zones ranging from 14 to 16 mm. Minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC values ranged from 16 to 32 µg/mL and 128 to 512 µg/mL, respectively. Time-kill assay showed that the extract had remarkable bactericidal effects on L. monocytogenes. The extract at a concentration of 16 µg/mL reduced tolerance to 10% NaCl in L. monocytogenes in 4 h. Stationary phase L. monocytogenes cells were rapidly inactivated by greater than 3-log units within 30 min of contact time with R. tomentosa extract at 128 µg/mL. Electron microscopy revealed fragmentary bacteria with changes in the physical and morphological properties. Our study demonstrates the potential of the extract for further development into a bio-control agent in food to prevent the incidence of L. monocytogenes contamination.

  16. 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. PMID:27121573

  17. Potential Bio-Control Agent from Rhodomyrtus tomentosa against Listeria monocytogenes

    Science.gov (United States)

    Odedina, Grace Fiyinfoluwa; Vongkamjan, Kitiya; Voravuthikunchai, Supayang Piyawan

    2015-01-01

    Listeria monocytogenes is an important foodborne pathogen implicated in many outbreaks of listeriosis. This study aimed at screening for the potential use of Rhodomyrtus tomentosa ethanolic leaf extract as a bio-control agent against L. monocytogenes. Twenty-two L. monocytogenes isolates were checked with 16 commercial antibiotics and isolates displayed resistance to 10 antibiotics. All the tested isolates were sensitive to the extract with inhibition zones ranging from 14 to 16 mm. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranged from 16 to 32 µg/mL and 128 to 512 µg/mL, respectively. Time-kill assay showed that the extract had remarkable bactericidal effects on L. monocytogenes. The extract at a concentration of 16 µg/mL reduced tolerance to 10% NaCl in L. monocytogenes in 4 h. Stationary phase L. monocytogenes cells were rapidly inactivated by greater than 3-log units within 30 min of contact time with R. tomentosa extract at 128 µg/mL. Electron microscopy revealed fragmentary bacteria with changes in the physical and morphological properties. Our study demonstrates the potential of the extract for further development into a bio-control agent in food to prevent the incidence of L. monocytogenes contamination. PMID:26371033

  18. 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.

  19. Management of Brown Leaf Rust, Puccinia recondita of Wheat Using Natural Products and Biocontrol Agents

    Directory of Open Access Journals (Sweden)

    Hamdy A. Eldoksch

    2001-01-01

    Full Text Available The effect of biocontrol agents and natural products on brown leaf rust, Puccinia recondita f.sp. tritici, of wheat were studied under greenhouse and field conditions in 1998/99 and 1999/2000 seasons. Under greenhouse conditions, application of Plant guard (Trichoderma harizianum, Rhizo-N (Bacillus subtilis and the yeast (Saccharomyces cerevisiae gave reasonable control of leaf rust severity with disease reduction percentages of 64.29, 57.14 and 19.14%, respectively. Field application of formulated natural products during two successive seasons gave effective control of brown rust disease. Natural oil, peppermint oil, jojoba oil, eucalyptus oil and chenopodium oil were the most effective treatments in reducing leaf rust severity and also in improving grain yield. All natural products significantly reduced the rust disease incidence in wheat by 55.5-98.2% and subsequently led to an increase in the grain yield that ranged from 8.5-51.8%. Of the biocontrol agents applied in the field, Plant guard was the most effective treatment followed by yeast and then Rhizo-N. These bioagents significantly improved grain yield and increased 100 kernel weight relative to the untreated control. Sumi-8 fungicide (diniconazole showed complete protection against rust disease incidence in both greenhouse and field trials.

  20. 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. PMID:27052703

  1. 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

    2003-12-23

    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

  2. Implementing plant biostimulants and biocontrol strategies in the agroecological management of cultivated ecosystems. A review

    Directory of Open Access Journals (Sweden)

    Le Mire, G.

    2016-01-01

    Full Text Available Introduction. In the context of sustainable agricultural production, agroecology aims at optimizing the economic and environmental performances of beneficial ecosystem services in order to (i increase the productivity and resilience of cultivated ecosystems and (ii preserve their natural resources. The maintenance of such performances is supported by research via the development of new tools that enhance plant tolerance to numerous biotic and abiotic stresses. Literature. Biostimulants can be used as a tool to complement the use of chemical inputs, by involving non-living-based products, or living-based products containing beneficial rhizosphere microbiome, such as plant growth-promoting rhizobacteria (PGPR. Pest management research has also made major advances in the development of efficient biocontrol methods. Elicitors and semiochemicals are considered to be some of the most promising tools for inducing plant resistance to various diseases and enhancing natural predation, respectively. Several products are already on the market. This review discusses current methods for exploiting and applying biostimulant and biocontrol products in contemporary agricultural systems. Future applications of these tools for sustainable management of cultivated ecosystems are also discussed. Conclusions. These tools are still difficult to use because of their lack of reliability in the field and their uneasy integration in the cropping systems. Further studies are needed to better understand the parameters influencing the efficiency of PGPR, elicitors and semiochemicals. Special attention needs to be given to the formulation and the interactions of these products with plant physiology and the environment.

  3. 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.

  4. Lactic acid bacteria from fresh fruit and vegetables as biocontrol agents of phytopathogenic bacteria and fungi.

    Science.gov (United States)

    Trias, Rosalia; Bañeras, Lluís; Montesinos, Emilio; Badosa, Esther

    2008-12-01

    This study evaluated the efficacy of lactic acid bacteria (LAB) isolated from fresh fruits and vegetables as biocontrol agents against the phytopathogenic and spoilage bacteria and fungi, Xanthomonas campestris, Erwinia carotovora, Penicillium expansum, Monilinia laxa, and Botrytis cinerea. The antagonistic activity of 496 LAB strains was tested in vitro and all tested microorganisms except P. expansum were inhibited by at least one isolate. The 496 isolates were also analyzed for the inhibition of P. expansum infection in wounds of Golden Delicious apples. Four strains (TC97, AC318, TM319, and FF441) reduced the fungal rot diameter of the apples by 20%; only Weissella cibaria strain TM128 decreased infection levels by 50%. Cell-free supernatants of selected antagonistic bacteria were studied to determine the nature of the antimicrobial compounds produced. Organic acids were the preferred mediators of inhibition but hydrogen peroxide was also detected when strains BC48, TM128, PM141 and FF441 were tested against E. carotovora. While previous reports of antifungal activity by LAB are scarce, our results support the potential of LAB as biocontrol agents against postharvest rot. PMID:19204894

  5. 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. PMID:26686620

  6. 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.

  7. 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. PMID:26946374

  8. Controlled release of Pantoea agglomerans E325 for biocontrol of fire blight disease of apple.

    Science.gov (United States)

    Kim, In-Yong; Pusey, Paul Lawrence; Zhao, Youfu; Korban, Schuyler S; Choi, Hyungsoo; Kim, Kyekyoon Kevin

    2012-07-10

    Microencapsulation and controlled release of the biocontrol agent Pantoea agglomerans strain E325 (E325), an antagonist to the bacterial plant pathogen Erwinia amylovora that causes fire blight, a devastating disease of apple and pear, have been investigated. Uniform core-shell alginate microcapsules (AMCs), 60-300 μm in diameter, were fabricated to encapsulate E325 within the core, along with nutrients, to preserve viability and promote proliferation. Controlled release of E325 was achieved by separately adjusting alginate concentrations in the shell and core solutions, and by modifying the AMC size. Viability of E325 was monitored via fluorescent staining, revealing either lack of or minimal stress during or after encapsulation. Proliferation of E325 within AMCs, followed by their subsequent release, and colonization activities within confines of apple flowers were studied under different encapsulation conditions using rfp-labeled E325 to obtain highly promising results. This study provided a 'proof of concept' of the successful use of a microencapsulated biocontrol agent, E325, against E. amylovora, and could serve as a model for further studies on the development of effective plant disease management strategies. PMID:22516094

  9. Biocontrol mechanism by root-associated Bacillus amyloliquefaciens FZB42 - a review

    Directory of Open Access Journals (Sweden)

    Soumitra ePaul Chowdhury

    2015-07-01

    Full Text Available Bacillus amyloliquefaciens subsp. plantarum FZB42 is a gram-positive model bacterium for unraveling plant-microbe interactions in Bacilli. In addition, FZB42 is used commercially as biofertilizer and biocontrol agent in agriculture. Genome analysis of FZB42 revealed that nearly 10% of the FZB42 genome is devoted to synthesizing antimicrobial metabolites and their corresponding immunity genes. However, recent investigations in planta demonstrated that - except surfactin - the amount of such compounds found in vicinity of plant roots is relatively low, making doubtful a direct function in suppressing competing microflora including plant pathogens. These metabolites have been also suspected to induce changes within the rhizosphere microbial community, which might affect environment and plant health. However, sequence analysis of rhizosphere samples revealed only marginal changes in the root microbiome, suggesting that secondary metabolites are not the key factor in protecting plants from pathogenic microorganisms. On the other hand, adding FZB42 to plants compensate, at least in part, changes in the community structure caused by the pathogen, indicating an interesting mechanism of plant protection by beneficial Bacilli.Sub-lethal concentrations of cyclic lipopeptides and volatiles produced by plant-associated Bacilli trigger pathways of induced systemic resistance (ISR, which protect plants against attacks of pathogenic microbes, viruses and nematodes. Stimulation of ISR by bacterial metabolites is likely the main mechanism responsible for biocontrol action of FZB42.

  10. Effects of nitrogen availability and spore concentration on the biocontrol activity of Ascochyta caulina in common lambsquarters (Chenopodium album)

    NARCIS (Netherlands)

    Ghorbani, R.; Scheepens, P.C.; Zweerde, van der W.; Leifert, C.; McDonald, A.J.S.; Seel, W.

    2002-01-01

    Common lambsquarters is an annual weed of many important crops. Ascochyta caulina is a plant pathogenic fungus that causes necrotic lesions on the leaves and stems of common lambsquarters. The objective of the present study was to estimate the effect of plant N supply on the biocontrol activity of A

  11. Biocontrol potential of Steinernema thermophilum and its symbiont Xenorhabdus indica against lepidopteran pests: virulence to egg and larval stages

    Science.gov (United States)

    Under laboratory conditions, the biocontrol potential of Steinernema thermophilum was tested against eggs and larval stages of two important lepidopteran insect pests, Helicoverpa armigera and Spodoptera litura (polyphagous pests), as well as Galleria mellonella (used as a model host) . In terms of ...

  12. Functional and Structural Microbial Diversity in Organic and Conventional Viticulture: Organic Farming Benefits Natural Biocontrol Agents ▿ †

    OpenAIRE

    Schmid, Florian; Moser, Gerit; Müller, Henry; Berg, Gabriele

    2011-01-01

    Statistically significant differences in the structure and function of above-ground grapevine-associated microorganisms from organically and conventionally managed vineyards were found. Aureobasidium pullulans, a copper-detoxifying fungus and biocontrol agent, plays a key role in explaining these differences. The black fungus was strongly enriched in the communities of organically managed plants and yielded a higher indigenous antiphytopathogenic potential.

  13. CUTICULAR HYDROCARBONS OF THE FLEA BEETLES, APHTHONA LACERTOSA AND APHTHONA NIGRISCUTIS, BIOCONTROL AGENTS FOR LEAFY SPURGE, EUPHORBIA ESULA

    Science.gov (United States)

    The adult beetles, Aphthona lacertosa and Aphthona nigriscutis, used as biocontrol agents for leafy spurge, had a complex mixture of hydrocarbons on their cuticular surface consisting of alkanes, methylalkanes, alkenes and alkadienes as determined by gas chromatography-mass spectrometry. In both ...

  14. Biocontrol of Escherichia coli O157:H7 on fresh-cut lettuce and cantaloupe by treatment with bacteriophage

    Science.gov (United States)

    Introduction: Outbreaks of foodborne illness have been associated with the consumption of cantaloupes and fresh-cut lettuce. Bacteriophage mixtures may be effective biocontrol agents to reduce E. coli O157:H7 on produce. Purpose: The effectiveness of a mixture of bacteriophages (ECP-100) in reducin...

  15. Complete Genome Sequence of Pseudomonas fluorescens LBUM636, a Strain with Biocontrol Capabilities against Late Blight of Potato.

    Science.gov (United States)

    Morrison, Christopher K; Novinscak, Amy; Gadkar, Vijay J; Joly, David L; Filion, Martin

    2016-01-01

    Herein provided is the full-genome sequence of Pseudomonas fluorescens LBUM636. This strain is a plant growth-promoting rhizobacterium (PGPR) which produces phenazine-1-carboxylic acid, an antibiotic involved in the biocontrol of numerous plant pathogens, including late blight of potato caused by the plant pathogen Phytophthora infestans. PMID:27231373

  16. 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

  17. 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. PMID:27220011

  18. Use of biocontrol organisms and compost amendments for improved control of soilborne diseases and increased potato production

    Science.gov (United States)

    Soilborne potato diseases are persistent problems in potato production and alternative management practices are needed. In this research, biocontrol agents (Bacillus subtilis GB03 and Rhizoctonia solani hypovirulent isolate Rhs1A1) and compost amendments (from different source material), were evalua...

  19. 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...

  20. Transformation of Cyclaneusma minus with Green Fluorescent Protein (GFP to Enable Screening of Fungi for Biocontrol Activity

    Directory of Open Access Journals (Sweden)

    Alison Stewart

    2012-02-01

    Full Text Available Cyclaneusma needle-cast has a major impact on the New Zealand forest industry. The causal agent, Cyclaneusma minus, causes most severe damage to 11–20 year-old trees and currently there are no economically viable procedures for control of the disease in New Zealand. Here we present a method for genetic transformation of C. minus using protoplasts generated by incubation with Glucanex™ enzyme. C. minus was transformed with a gene encoding green fluorescent protein (GFP and expression was stable after successive sub-culturing of the strain in the absence of selective pressure. Expression of the gfp gene allowed us to utilize an in vitro GFP-based screening method to identify strains of Trichoderma with potential for biocontrol of this disease. The strain that showed the most promise as a potential biocontrol candidate exhibited a low level of inhibition by uncharacterized metabolite(s that C. minus secretes into the medium, and consistently caused a loss of GFP expression from the GFP-labeled C. minus strain. The interaction between C. minus and the biocontrol strain, in the interaction zone where GFP expression was lost, was determined to be fungicidal. The utility of such biocontrol strains is discussed. This study represents the first genetic manipulation of C. minus and will pave the way for further studies of the life cycle and infection biology of this organism.

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

    International Nuclear Information System (INIS)

    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. - Highlights: • A suitable method to reduce apple quality losses during 9 month storage period. • Effects of γ radiation in combination with biocontrol agent on physico-chemical parameters of the apple fruits during cold storage. • The potential dual benefit of low irradiation dose combined with biocontrol agent. • Radiation dose determination for Penicillium expansum (postharvest pathogen) control

  2. 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

  3. Potencialidade de um actinomiceto de rizosfera de tomateiro como agente de biocontrole de doenças Potenciality of an actinomycete from tomato rhizosphere as a biocontrol agent for tomato diseases

    Directory of Open Access Journals (Sweden)

    Renato Carrer Filho

    2009-09-01

    Full Text Available Um actinomiceto (Streptomyces setonii, isolado 'UFV-RD1', obtido de rizosfera de planta sadia de tomateiro, foi selecionado dentre outros 117, como promissor agente de biocontrole de enfermidades da cultura. Em testes de antagonismo in vitro contra patógenos do tomateiro, o isolado 'UFV-RD1' foi incapaz de inibir o crescimento de bactérias (Pseudomonas syringae pv. tomato, Ralstonia solanacearum, Pectobacterium carotovorum subsp. carotovorum, Xanthomonas campestris pv. vesicatoria mas inibiu a germinação de conídios de alguns fungos (Alternaria solani, Phytophthora infestans, Corynespora cassiicola, Stemphylium solani. Em ensaios de biocontrole experimental in vivo, em casa de vegetação, o actinomiceto foi efetivo em reduzir a severidade de sintomas no caso de patógenos fúngicos e bacterianos testados como desafiantes. A campo, quando A. solani e P. infestans ocorreram naturalmente, as plantas originárias de sementes microbiolizadas com propágulos da estirpe 'UFV-RD1' exibiram sintomas menos severos que as plantas controle para o caso da pinta preta. O agente de biocontrole é promissor para futuros protocolos de manejo integrado, como forma de reduzir a quantidade de defensivos utilizados.An actinomycete (Streptomyces setonii, isolate 'UFV-RD1', isolated from the rhizosphere of a healthy tomato plant was selected out of 117 as a promising biocontrol agent for tomato diseases. In in vitro antagonism tests against tomato pathogens, the isolate 'UFV-RD1' was unable to inhibit growth of bacterial pathogens (Pseudomonas syringae pv. tomato, Ralstonia solanacearum, Pectobacterium carotovorum subsp. carotovorum, Xanthomonas campestris pv. vesicatoria but inhibited conidium germination of fungi (Alternaria solani, Phytophthora infestans, Corynespora cassiicola, Stemphylium solani. Experimental biocontrol assays in a greenhouse indicated that the actinomycete was effective for reducing symptom severity in the case of bacteria and fungi tested

  4. 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. PMID:21190787

  5. 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

  6. EFFICACY OF BIOCONTROL AGENTS IN CONTROLLING RHIZOCTONIA SOLANI ON NAGA KING CHILLI ( Capsicum chinense Jacq.

    Directory of Open Access Journals (Sweden)

    Marinus Ngullie

    2013-07-01

    Full Text Available Available biocontrol agents were evaluated either alone or in various combinations for finding out their efficacy in suppressing Rhizoctonia seedling rot incidence and promoting plant growth of Naga king chilli (Capsicum chinense Jacq. in green house as well field conditions. Among all tested combination, the treatment containing combination of T. viride +P. fluorescens was found most effective in reducing the incidence of seedling rot in both greenhouse and field condition. Highest per plant yield was also recorded from the same combination and it was followed by T. viride. However, the commercially available fungicide Copper oxychloride (0.1% showed 9.82 % and11.88% disease incidence in greenhouse and field condition respectively

  7. Production of a newly isolated Paenibacillus polymyxa biocontrol agent using monosodium glutamate wastewater and potato wastewater.

    Science.gov (United States)

    Gu, Likun; Bai, Zhihui; Jin, Bo; Zhang, Jianyun; Li, Wenying; Zhuang, Guoqiang; Zhang, Hongxun

    2010-01-01

    A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater (MGW) and potato wastewater (PW) as culture medium. The maximum yield of 6.5 x 10(9) CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28 degrees C, pH 6.0-7.5 using the mixture of MGW and PW (1:9). PMID:21174972

  8. A Novel Bacteriophage Targeting Cronobacter sakazakii Is a Potential Biocontrol Agent in Foods.

    Science.gov (United States)

    Lee, Ju-Hoon; Bai, Jaewoo; Shin, Hakdong; Kim, Yeran; Park, Bookyung; Heu, Sunggi; Ryu, Sangryeol

    2016-01-01

    Cronobacter sakazakii is an important pathogen that causes high mortality in infants. Due to its occasional antibiotic resistance, a bacteriophage approach might be an alternative effective method for the control of this pathogen. To develop a novel biocontrol agent using bacteriophages, the C. sakazakii-infecting phage CR5 was newly isolated and characterized. Interestingly, this phage exhibited efficient and relatively durable host lysis activity. In addition, a specific gene knockout study and subsequent complementation experiment revealed that this phage infected the host strain using the bacterial flagella. The complete genome sequence analysis of phage CR5 showed that its genome contains 223,989 bp of DNA, including 231 predicted open reading frames (ORFs), and it has a G+C content of 50.06%. The annotated ORFs were classified into six functional groups (structure, packaging, host lysis, DNA manipulation, transcription, and additional functions); no gene was found to be related to virulence or toxin or lysogen formation, but >80% of the predicted ORFs are unknown. In addition, a phage proteomic analysis using SDS-PAGE and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) revealed that seven phage structural proteins are indeed present, supporting the ORF predictions. To verify the potential of this phage as a biocontrol agent against C. sakazakii, it was added to infant formula milk contaminated with a C. sakazakii clinical isolate or food isolate, revealing complete growth inhibition of the isolates by the addition of phage CR5 when the multiplicity of infection (MOI) was 10(5). PMID:26497465

  9. 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.

  10. Identification of bacteriophages for biocontrol of the kiwifruit canker phytopathogen Pseudomonas syringae pv. actinidiae.

    Science.gov (United States)

    Frampton, Rebekah A; Taylor, Corinda; Holguín Moreno, Angela V; Visnovsky, Sandra B; Petty, Nicola K; Pitman, Andrew R; Fineran, Peter C

    2014-04-01

    Pseudomonas syringae pv. actinidiae is a reemerging pathogen which causes bacterial canker of kiwifruit (Actinidia sp.). Since 2008, a global outbreak of P. syringae pv. actinidiae has occurred, and in 2010 this pathogen was detected in New Zealand. The economic impact and the development of resistance in P. syringae pv. actinidiae and other pathovars against antibiotics and copper sprays have led to a search for alternative management strategies. We isolated 275 phages, 258 of which were active against P. syringae pv. actinidiae. Extensive host range testing on P. syringae pv. actinidiae, other pseudomonads, and bacteria isolated from kiwifruit orchards showed that most phages have a narrow host range. Twenty-four were analyzed by electron microscopy, pulse-field gel electrophoresis, and restriction digestion. Their suitability for biocontrol was tested by assessing stability and the absence of lysogeny and transduction. A detailed host range was performed, phage-resistant bacteria were isolated, and resistance to other phages was examined. The phages belonged to the Caudovirales and were analyzed based on morphology and genome size, which showed them to be representatives of Myoviridae, Podoviridae, and Siphoviridae. Twenty-one Myoviridae members have similar morphologies and genome sizes yet differ in restriction patterns, host range, and resistance, indicating a closely related group. Nine of these Myoviridae members were sequenced, and each was unique. The most closely related sequenced phages were a group infecting Pseudomonas aeruginosa and characterized by phages JG004 and PAK_P1. In summary, this study reports the isolation and characterization of P. syringae pv. actinidiae phages and provides a framework for the intelligent formulation of phage biocontrol agents against kiwifruit bacterial canker. PMID:24487530

  11. 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. PMID:27161758

  12. 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. PMID:24261038

  13. 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. PMID:27339311

  14. 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.

  15. An alpha-glucan elicitor from the cell wall of a biocontrol binucleate Rhizoctonia isolate.

    Science.gov (United States)

    Wolski, Erika A; Lima, Carlos; Agusti, Rosalía; Daleo, Gustavo R; Andreu, Adriana B; de Lederkremer, Rosa M

    2005-03-21

    Binucleate Rhizoctonia (BNR) isolate (232-C6) is an effective biocontrol agent for protection of potato from Rhizoctonia canker, a disease caused by Rhizoctonia solani. Production of hydrolytic enzymes is one of the best known inducible defense responses following microbial infection. We isolated and characterized a cell wall alpha-glucan from BNR, which induces beta-1,3 glucanase activities in potato sprouts, the primary site of infection by R. solani. An autoclaving method, previously reported for isolation of oligosaccharide elicitors was used, and the glucan purified by chromatographic techniques. Maximal induction of beta-1,3 glucanase activity in potato sprouts was obtained with 250 microg of the alpha-glucan elicitor after 6 days from inoculation time. Both, BNR mycelium and the alpha-glucan produced a similar kinetic response of beta-1,3 glucanase. However, the alpha-glucan did not induce phytoalexin accumulation, previously correlated with the defense response. Uronic acids (approximately 10% with respect to total neutral sugars) were determined and identified as glucuronic acid by high-pH anion-exchange chromatography. Methylation analysis showed that the glucan consists of (1-->3) and (1-->4)-linked glucose units with preponderance of the first ones. Some of the (1-->4) linkages were branched at position 6. The glucan was partially degraded with amyloglucosidase. This, together with the NMR spectra data and the high optical rotation of the original (+195 degrees ) and degraded glucans (+175 degrees ) proved the alpha configuration. Further methylation of the amyloglucosidase degraded glucans indicated that they consist of (1-->3)-linked glucoses. The present study is the first report on the isolation and characterization of an alpha-glucan from Rhizoctonia, that may be important as a biocontrol factor. PMID:15721332

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

    Science.gov (United States)

    Pérez, Esclaudys; Rubio, M Belén; Cardoza, Rosa E; Gutiérrez, Santiago; Bettiol, Wagner; Monte, Enrique; Hermosa, Rosa

    2015-01-01

    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 pathogenesis

  17. 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

  18. 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

  19. Microscopic Examination of Chitosan Polyphosphate Beads with Entrapped Spores of the Biocontrol Agent, Streptomyces melanosporofaciens EF-76

    Science.gov (United States)

    Jobin, Guy; Grondin, Gilles; Couture, Geneviève; Beaulieu, Carole

    2005-04-01

    Spores of the biocontrol agent, Streptomyces melanosporofaciens EF-76, were entrapped by complex coacervation in beads composed of a macromolecular complex (MC) of chitosan and polyphosphate. A proportion of spores entrapped in beads survived the entrapment procedure as shown by treating spores from chitosan beads with a dye allowing the differentiation of live and dead cells. The spore-loaded chitosan beads could be digested by a chitosanase, suggesting that, once introduced in soil, the beads would be degraded to release the biocontrol agent. Spore-loaded beads were examined by optical and scanning electron microscopy because the release of the biological agent depends on the spore distribution in the chitosan beads. The microscopic examination revealed that the beads had a porous surface and contained a network of inner microfibrils. Spores were entrapped in both the chitosan microfibrils and the bead lacuna.

  20. Isolation and selection of local isolates of chitinolitic bacteria that potent to biocontrol of larva stadia of Aedes aegypti L.

    Directory of Open Access Journals (Sweden)

    SRI PUJIYANTO

    2008-01-01

    Full Text Available The dengue fever was the most dangerously epidemic in Indonesia, so it is important to prevent the population of Aedes aegypti L. The larva stages of Ae. aegypti had an exosceleton from chitin, so if its exosceleton had been degraded the larva would be died. Many bacteria had chitin degradation activities, and the bacteria had potential as a biocontrol for Ae. aegypti larva stages. This research was got many of the local chitinolitic bacteria that had been potential as a biocontrol for Ae. aegypti larva stages. The chitinolitic bacteria were isolated with selective agar medium. The sources of isolates were collected from Central Java and West Java water resources. Selected isolates was done to get the higher chitinolitic activity in mineral water medium. The isolate LMB1-5 was potential as a bioinsecticide for Ae. aegypti larva stages. This isolate decreased 86.7% of the larva population in 7 days.

  1. Ecological impacts of Phlebiopsis gigantea biocontrol treatment against Heterobasidion spp. as revealed by fungal community profiling and population analyses

    OpenAIRE

    Vainio, Eeva Johanna

    2008-01-01

    Wood decay fungi belonging to the species complex Heterobasidion annosum sensu lato are among the most common and economically important species causing root rot and stem decay in conifers of the northern temperate regions. New infections by these pathogens can be suppressed by tree stump treatments using chemical or biological control agents. In Finland, the corticiaceous fungus Phlebiopsis gigantea has been formulated into a commercial biocontrol agent called Rotstop (Verdera Ltd.). Th...

  2. Production and oil-emulsion formulation of Cadophora malorum and Alternaria jacinthicola, two biocontrol agents against Water Hyacinth (Eichhornia crassipes)

    OpenAIRE

    Dagno, Karim; Lahlali, Rachid; Diourté, Mamourou; Jijakli, Haissam

    2011-01-01

    Cadophora malorum isolate Mln715 and Alternaria jacinthicola strain MUCL 53159 are under development as biocontrol agents against Water Hyacinth (Eichhornia crassipes) in Mali. Production of spores of these agents on locally available substrates (Water Hyacinth, powdered paddy rice chaff, wheat semolina) was assessed with a view to mass production. The C. malorum isolate sporulated best on Water Hyacinth (4.08 × 107 spores ml-1), followed by wheat (1.06 ×107 spores ml-1), whereas A. jacint...

  3. 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. PMID:25259695

  4. Compounds produced by two robust Bacillus amyloliquefaciens biocontrol strains involved in antimicrobial activity and plant-growth promotion

    OpenAIRE

    Magno-Pérez, Maria Concepción; Hierrezuelo, Jesús; de Vicente, Antonio; Pérez-García, Alejandro; Romero, Diego

    2015-01-01

    Several members of the Bacillus genus are potential candidates to be used as biological control agents to combat pests or plant diseases. The bacterial attributes associated to Bacillus behaviour are mainly: the production of antimicrobial compounds, the plant-growth promotion capability and the induction of systemic resistance in plant host. In previous works, we have demonstrated this multifaceted biocontrol activity of B. amyloliquefaciens CECT8237 (UMAF6639) and CECT8238 (UMAF6614) strain...

  5. Nonribosomal peptides, key biocontrol components for Pseudomonas fluorescens In5, isolated from a Greenlandic suppressive soil

    OpenAIRE

    Michelsen, Charlotte Frydenlund; Watrous, Jeramie; Glaring, Mikkel Andreas; Kersten, Roland; Koyama, Nobuhiro; Dorrestein, Pieter C.; Peter STOUGAARD

    2015-01-01

    ABSTRACT Potatoes are cultivated in southwest Greenland without the use of pesticides and with limited crop rotation. Despite the fact that plant-pathogenic fungi are present, no severe-disease outbreaks have yet been observed. In this report, we document that a potato soil at Inneruulalik in southern Greenland is suppressive against Rhizoctonia solani Ag3 and uncover the suppressive antifungal mechanism of a highly potent biocontrol bacterium, Pseudomonas fluorescens In5, isolated from the s...

  6. In Vitro Screening for Abiotic Stress Tolerance in Potent Biocontrol and Plant Growth Promoting Strains of Pseudomonas and Bacillus spp.

    OpenAIRE

    G. Praveen Kumar; Mir Hassan Ahmed, S. K.; Suseelendra Desai; Leo Daniel Amalraj, E.; Abdul Rasul

    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 desire...

  7. 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.

  8. 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.

  9. 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.

  10. 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. PMID:26635750

  11. [Colonization characteristics of endophytic bacteria NJ13 in Panax ginseng and its biocontrol efficiency against Alternaria leaf spot of ginseng].

    Science.gov (United States)

    Chen, Chang-Qing; Li, Tong; Li, Xin-Lian; Jiang, Yun; Tian, Lei; Xu, Peng

    2014-05-01

    To reveal the colonization characteristics in host of endophytic biocontrol bacteria NJ13 isolated from Panax ginseng, this study obtained the marked strain NJ13-R which was double antibiotic resistant to rifampicin and streptomycin through enhancing the method of inducing antibiotic. The colonization characteristics in ginseng and its biocontrol efficiency against Alternaria spot of ginseng in the field were studied. The results showed that the strain could colonize in root, stem and leaf of ginseng and the colonization amount was positive correlated with inoculation concentration. Meanwhile, the strain could infect and then transfer in different tissues of ginseng The colonization amount of strain in roots and leaves of ginseng increased first and then decreased. However, the tendency of colonization amount of strain in stems was ascend at first and then descend slowly, and was more than that in roots and leaves along with time, which had a preference to specific tissue of its host. In field experiment, the endophytic bacteria NJ13 was proved to be effective in controlling Alternaria leaf spot of ginseng. The biocontrol efficiency of fermentation broth at the concentration of 0.76 x 10(8) cfu x mL(-1) reached 75.62%, which was close to the controlling level (73.06%) of 0.67 mg x L(-1) 50% cyprodinil WG. PMID:25282882

  12. Development of species-, strain- and antibiotic biosynthesis-specific quantitative PCR assays for Pantoea agglomerans as tools for biocontrol monitoring.

    Science.gov (United States)

    Braun-Kiewnick, Andrea; Lehmann, Andreas; Rezzonico, Fabio; Wend, Chris; Smits, Theo H M; Duffy, Brion

    2012-09-01

    Pantoea agglomerans is a cosmopolitan plant epiphytic bacterium that includes some of the most effective biological antagonists against the fire blight pathogen Erwinia amylovora, a major threat to pome fruit production worldwide. Strain E325 is commercially available as Bloomtime Biological™ in the USA and Canada. New quantitative PCR (qPCR) assays were developed for species- and strain -specific detection in the environment, and for detection of indigenous strains carrying the biocontrol antibacterial peptide biosynthesis gene paaA. The qPCR assays were highly specific, efficient and sensitive, detecting fewer than three cells per reaction or 700 colony forming units per flower, respectively. The qPCR assays were tested on field samples, giving first indications to the incidence of P. agglomerans E325 related strains, total P. agglomerans and pantocin A producing bacteria in commercial orchards. These assays will facilitate monitoring the environmental behavior of biocontrol P. agglomerans after orchard application for disease protection, proprietary strain-tracking, and streamlined screening for discovery of new biocontrol strains. PMID:22705381

  13. IMPROVMENT BIOCONTROL OF DAMPING-OFF AND ROOT ROT/WILT OF FABA BEAN BY SALICYLIC ACID AND HYDROGEN PEROXIDE

    Directory of Open Access Journals (Sweden)

    Montaser F. Abdel-Monaim

    2013-04-01

    Full Text Available Rhizoctonia solani, Fusarium solani, F. oxysporum and Macrophomina phaseolina were found to be associated with root rot and wilt symptoms of faba bean plants collected from different fields 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, Bacillus megaterium and chemical inducers (salicylic acid and hydrogen peroxide individually or in combination were examined for biological control of damping-off and root rot/wilt and growth promotion 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 survival of plants. Also, these treatments increased fresh and dry weights of the survived plants in pots compared with control.  The combination of biocontrol agents and chemical inducers were more effective than using them individually and SA+ T. viride was the best treatment in this respect. Under field conditions, all these treatments significantly increased growth parameters (plant height and No. of branches plant-1 and yield components (No. of pods and seedsplant-1, weight of 100 seeds and total yield feddan-1 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 combination of biocontrol agents and

  14. 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

  15. Current and potential management strategies against Harmonia axyridis

    OpenAIRE

    Kenis, Marc; Roy, Helen E.; Zindel, Renate; Majerus, Michael E. N.

    2008-01-01

    This paper reviews the current and potential methods to control the harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), an Asian predatory beetle invasive in Europe and the Americas where it has become a human nuisance, a grape and wine pest and a threat to native biodiversity. Current methods to manage this invasive species include: techniques to mechanically prevent adult beetles from entering buildings in autumn or to remove aggregates of beetles inside buildings, e...

  16. 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.

  17. Chitin enhances biocontrol of Rhodotorula mucilaginosa to postharvest decay of peaches.

    Science.gov (United States)

    Zhang, Hongyin; Yang, Qiya; Ge, Lingling; Zhang, Guochao; Zhang, Xiaoli; Zhang, Xiaoyun

    2016-07-01

    Biological control using microbial antagonists is a promising alternative approach to synthetic fungicides. However, effective biological control requires enhancing the consistency and efficacy of the antagonists used to control postharvest diseases. This study investigated the effect of chitin on the biocontrol efficacy of Rhodotorula mucilaginosa against blue mold and Rhizopus decay of peaches and on the protein expression profiles of R. mucilaginosa. The antagonistic activity of R. mucilaginosa harvested from the nutrient yeast dextrose broth (NYDB) with 0.5% chitin added was significantly improved compared with culture in NYDB without chitin. The R. mucilaginosa population cultured in chitin-supplement NYDB and nutrient yeast chitin borth (NYCB) harvested from peach wounds was more than that of R. mucilaginosa cultured in NYDB without chitin throughout the storage period except at 1 d. The protein expression profiles findings revealed that there were several differentially expressed proteins of R. mucilaginosa in the 0.5% chitin-supplemented NYDB and NYCB compared with that of R. mucilaginosa in NYDB. Most of these were cellular proteomes relating to the primary metabolic reactions such as glycoside hydrolases, phosphoribosyl pyrophosphate, and NADH dehydrogenases. Some proteins were also related to signal transmission and stress response. PMID:27064085

  18. Purification of an antifungal endochitinase from a potential biocontrol Agent Streptomyces griseus.

    Science.gov (United States)

    Rabeeth, M; Anitha, A; Srikanth, Geetha

    2011-08-15

    Streptomyces griseus (MTCC 9723) is a chitinolytic bacterium isolated from prawn cultivated pond soil of Peddapuram Village; East Godavari District was studied in detailed. Chitinase (EC 3.2.1.14) was extracted from the culture filtrate of Streptomyces griseus and purified by ammonium sulfate precipitation, DEAE-cellulose ionexchange chromatography, Sephadex G-100 and Sephadex G-200 gel filtration chromatography. The molecular mass of the purified chitinase was estimated to be 34, 32 kDa by SDS gel electrophoresis and confirmed by activity staining with Calcofluor White M2R. Chitinase was optimally active at pH of 6.0 and at 40 degrees C. The enzyme was stable from pH 5-9 and up to 20-50 degrees C. The chitinase exhibited Km and Vmax values of 400 mg and 180 IU mL(-1) for colloidal chitin. Among the metals and inhibitors that were tested, the Hg+, Hg2+ and P-chloromercuribenzoic acid completely inhibited the chitinase activity at 1 mM concentration. The purified chitinase showed high activity on colloidal chitin, chitobiose, and chitooligosaccharide. An in vitro assay proved that the crude chitinase, actively growing cells of S. griseus having antifungal activity against all studied fungal pathogen. This result implies that characteristics of S. griseus producing endochitinase made them suitable for biotechnological purpose such as for degradation of chitin containing waste and it might be a promising biocontrol agent for plant pathogens. PMID:22545353

  19. Chitinolytic Bacteria Isolated from Chili Rhizosphere: Chitinase Characterization and Application as Biocontrol for Aphis gossypii

    Directory of Open Access Journals (Sweden)

    TARUNI SRI PRAWASTI

    2010-12-01

    Full Text Available Chitin, a common constituent of insect exoskeleton, could be hydrolyzed by chitinase. This research was conducted to select rhizobacteria isolated from the rhizosphere of chili pepper that produced chitinase and to examine their chitinase activity in degrading chitin of the Aphis gossypii. A total of 25 rhizobacteria isolates formed a clear zone when grown on chitin agar. Three of them had the highest chitinolytic index and were identified as Bacillus sp. strain I.5, I.21, and II.14. The II.14 was chosen for characterization of chitinase activity. The isolate showed maximum chitinase activity at 48-h-incubation. Maximum temperature and pH of the chitinase activity were 55°C and 7.0, respectively. The cell culture and the enzyme crude extract of the above three isolates were tested against A. gossypii and the result was compared to the control through microscopic observation. Hydrolytic analysis showed that the enzyme crude extract of these isolates were able to degrade chitin of insect exoskeleton since the first 3-h-incubation. Meanwhile, the cell culture treatment on the chitin showed degrading activity after 12 h (Bacillus sp. strain I.21 and II.14, and 9 h (Bacillus sp. strain I.5. Chitin degradation of A. gossypii exoskeleton by enzyme crude extract was better than the cell culture treatment. Chitinases produced by Bacillus sp. strains I.5, I.21, and II.14 are potential as biocontrol agents for A. gossypii.

  20. A full factorial analysis of nine factors influencing in vitro antagonistic screens for potential biocontrol agents.

    Science.gov (United States)

    Dickie, G A; Bell, C R

    1995-03-01

    The effect of nine factors on the outcome of classic in vitro screens testing the antagonistic action of endophytic bacterial isolates from grape vines against virulent Agrobacterium vitis has been examined. These factors were (i) the strain of A. vitis, (ii) the strain of endophyte, (iii) the growth medium of the pathogen, (iv) the growth medium of the endophyte, (v) the temperature of growth of the pathogen, (vi) the temperature of growth of the endophyte, (vii) the pH of growth of the pathogen, (viii) the pH of growth of the endophyte, and (ix) the medium of the assay plate. Analyses of variance of the full factorial design incorporating main effects and two- and three-way interactions accounted for 66% of the variance. All nine factors had a significant effect on the diameter of inhibition zones (p antagonism (especially the composition of the growth medium and the temperature of growth), had a profound effect on the outcome of the test. Generally the more chemically defined media produced less inhibition whereas the lower growth temperature of 15 degrees C produced more inhibition. These findings could be relevant to in situ inhibitory activity. The method used to conduct the inhibitory screen (order of strain application and the medium of the assay plate) had a profound influence on the results. These influences add to the caution necessary in the use of in vitro antagonistic screens for finding successful biocontrol agents. PMID:7736357

  1. 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

    2016-09-01

    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. PMID:27294522

  2. Rhizospheric bacteria of maize with potential for biocontrol of Fusarium verticillioides.

    Science.gov (United States)

    Figueroa-López, Alejandro Miguel; Cordero-Ramírez, Jesús Damián; Martínez-Álvarez, Juan Carlos; López-Meyer, Melina; Lizárraga-Sánchez, Glenda Judith; Félix-Gastélum, Rubén; Castro-Martínez, Claudia; Maldonado-Mendoza, Ignacio Eduardo

    2016-01-01

    The stalk, ear and root rot (SERR) of maize caused by Fusarium verticillioides (Fv) severely impacts crop production in tropical and subtropical regions. The aim of the present work was to screen bacterial isolates in order to find novel native biocontrol agents against Fv. A culturable bacterial collection consisting of 11,520 isolates enriched in Firmicutes and Proteobacteria was created from rhizosphere samples taken from SERR symptomatic or asymptomatic maize plants. The complete collection was screened for potential activity against Fv using a liquid antagonism assay followed by dual cultures in solid medium, selecting for 42 bacteria (Bacillus, Pseudomonas and Paenibacillus) that inhibit Fv growth (>45 %). In planta assays demonstrated that three Bacillus isolates: B. megaterium (B5), B. cereus sensu lato (B25) and Bacillus sp. (B35) displayed the highest antagonistic activity against Fv. Pot experiments performed in a greenhouse with Bacillus cereus sensu lato B25 confirmed these findings and showed a reduction of Fv disease severity and incidence on plants. Antagonistic activity analysis revealed that these strains produce glucanases, proteases or chitinases, as well as siderophores and auxins and suggests these as possible control mechanisms against Fv. PMID:27066355

  3. Improved delivery of biocontrol Pseudomonas and their antifungal metabolites using alginate polymers.

    Science.gov (United States)

    Russo, A; Moënne-Loccoz, Y; Fedi, S; Higgins, P; Fenton, A; Dowling, D N; O'Regan, M; O'Gara, F

    1996-02-01

    Alginate polymer was evaluated as a carrier for seed inoculation with a genetically modified strain Pseudomonas fluorescens F113LacZY, which protects sugar-beet against Pythium-mediated damping-off. F113LacZY survived in alginate beads at 5 log10 CFU/bead or higher counts for 8 weeks of storage, regardless of the conditions of incubation. In plant inoculation experiments, colonisation of the growing area of the root by F113LacZY, derived from alginate beads placed in the soil next to the seed or from an alginate coating around the seeds, was improved compared with application of just free cells of the strain. F113LacZY trapped in alginate beads was an effective producer of antifungal phloroglucinols as indicated by direct HPLC quantification of phloroglucinols and in vitro inhibition of both the indicator bacterium Bacillus subtilis A1 and the pathogenic fungus Pythium ultimum. Alginate polymer represents a promising carrier for the delivery of biocontrol inoculants for root colonisation and production of antifungal metabolites. PMID:8867631

  4. 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

  5. Characterization of Novel Trichoderma asperellum Isolates to Select Effective Biocontrol Agents Against Tomato Fusarium Wilt.

    Science.gov (United States)

    El Komy, Mahmoud H; Saleh, Amgad A; Eranthodi, Anas; Molan, Younes Y

    2015-03-01

    The use of novel isolates of Trichoderma with efficient antagonistic capacity against Fusarium oxysporum f. sp. lycopersici (FOL) is a promising alternative strategy to pesticides for tomato wilt management. We evaluated the antagonistic activity of 30 isolates of T. asperellum against 4 different isolates of FOL. The production of extracellular cell wall degrading enzymes of the antagonistic isolates was also measured. The random amplified polymorphic DNA (RAPD) method was applied to assess the genetic variability among the T. asperellum isolates. All of the T. asperellum isolates significantly reduced the mycelial growth of FOL isolates but the amount of growth reduction varied significantly as well. There was a correlation between the antagonistic capacity of T. asperellum isolates towards FOL and their lytic enzyme production. Isolates showing high levels of chitinase and β-1,3-glucanase activities strongly inhibited the growth of FOL isolates. RAPD analysis showed a high level of genetic variation among T. asperellum isolates. The UPGMA dendrogram revealed that T. asperellum isolates could not be grouped by their anta- gonistic behavior or lytic enzymes production. Six isolates of T. asperellum were highly antagonistic towards FOL and potentially could be used in commercial agriculture to control tomato wilt. Our results are consistent with the conclusion that understanding the genetic variation within Trichoderma isolates and their biochemical capabilities are required for the selection of effective indigenous fungal strains for the use as biocontrol agents. PMID:25774110

  6. OPTIMIZATION AND EVALUATION OF MICROBE FORTIFIED COMPOSTS AS BIOCONTROL AGENTS AGAINST PHYTOPATHOGENIC FUNGI

    Directory of Open Access Journals (Sweden)

    Ajinath S. Dukare

    2013-04-01

    Full Text Available A set of bacterial (B1-10 and cyanobacterial strains (C1-C14 were evaluated for their fungicidal activity against selected phytopathogenic fungi - Fusarium solani, Fusarium oxysporum, Fusarium oxysporum lycopersici, Fusarium moniliforme, Pythium debaryanum and Rhizoctonia solani. Further, they were used to amend rice straw compost and the filtrates were evaluated against the selected fungi after 10 and 20 days of incubation. Six promising strains, including three bacterial and three cyanobacterial strains were selected and characterised in terms of activity of hydrolytic enzymes. Interestingly, C12 strain (Anabaena spp. showed highest activity of cellulase, chitosanase and β 1, 3 glucanase. These strains were then evaluated by optimization of inoculum levels (1-5% in the rice straw compost. The strains B3, B5, C8 and C12 were observed to be most promising as they exhibited inhibition and significantly higher activity of microbiological parameters and hydrolytic enzymes at 1-2% level of inoculum in the compost. Further investigations are being undertaken to scale up the development of compost based biocontrol agents using these strains for evaluation at field level.

  7. 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.

  8. 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. PMID:25171761

  9. Candida parapsilosis as a Potent Biocontrol Agent against Growth and Aflatoxin Production by Aspergillus Species

    Science.gov (United States)

    Niknejad, F; Zaini, F; Faramarzi, MA; Amini, M; Kordbacheh, P; Mahmoudi, M; Safara, M

    2012-01-01

    Background: Aflatoxin contamination of food and feed stuff is a serious health problem and significant economic concerns. In the present study, the inhibitory effect of Candida parapsilosis IP1698 on mycelial growth and aflatoxin production in aflatoxigenic strains of Aspergillus species was investigated. Methods: Mycelial growth inhibitions of nine strains of aflatoxigenic and non-aflatoxigenic Aspergillus species in the presence of C. parapsilosis investigated by pour plate technique at different pH, temperature and time of incubation. Reduction of aflatoxin was evaluated in co-cultured fungi in yeast extract sucrose broth after seven days of incubation using HPLC method. The data were analyzed by SPSS 11.5. Results: The presence of the C. parapsilosis at different pH did not affect significantly the growth rate of Aspergillus isolates. On the other hand, temperature and time of incubation showed to be significantly effective when compared to controls without C. parapsilosis (P≤0.05). In aflatoxigenic strains, minimum percentage of reductions in total aflatoxin and B1, B2, G1, G2 fractions were 92.98, 92.54, 77.48, 54.54 and 72.22 and maximum percentage of reductions were 99.59, not detectable, 94.42, and not detectable in both G1 and G2, respectively. Conclusion: C. parapsilosis might employ as a good biocontrol agent against growth and aflatoxin production by aflatoxigenic Aspergillus species PMID:23308351

  10. Candida Parapsilosis as a Potent Biocontrol Agent against Growth and Aflatoxin Production by Aspergillus Species

    Directory of Open Access Journals (Sweden)

    F Niknejad

    2012-10-01

    Full Text Available Background: Aflatoxin contamination of food and feed stuff is a serious health problem and significant economic concerns. In the present study, the inhibitory effect of Candida parapsilosis IP1698 on mycelial growth and aflatoxin production in aflatoxigenic strains of Aspergillus species was investigated.Methods: Mycelial growth inhibitions of nine strains of aflatoxigenic and non-aflatoxigenic Aspergillus species in thepresence of C. parapsilosis investigated by pour plate technique at different pH, temperature and time of incubation.Reduction of aflatoxin was evaluated in co-cultured fungi in yeast extract sucrose broth after seven days of incubation using HPLC method. The data were analyzed by SPSS 11.5.Results: The presence of the C. parapsilosis at different pH did not affect significantly the growth rate of Aspergillus isolates. On the other hand, temperature and time of incubation showed to be significantly effective when compared to controls without C. parapsilosis (P≤0.05. In aflatoxigenic strains, minimum percentage of reductions in total aflatoxin and B1, B2, G1, G2 fractions were 92.98, 92.54, 77.48, 54.54 and 72.22 and maximum percentage ofreductions were 99.59, not detectable, 94.42, and not detectable in both G1 and G2, respectively.Conclusion: C. parapsilosis might employ as a good biocontrol agent against growth and aflatoxin production by aflatoxigenic Aspergillus species.

  11. Cucumber Rhizosphere Microbial Community Response to Biocontrol Agent Bacillus subtilis B068150

    Directory of Open Access Journals (Sweden)

    Lihua Li

    2015-12-01

    Full Text Available Gram-positive bacteria Bacillus subtilis B068150 has been used as a biocontrol agent against the pathogen Fusarium oxysporum cucumerinum. Cucumber was grown in three soils with strain B068150 inoculated in a greenhouse for 90 days, and the colonization ability of strain B068150 in cucumber rhizosphere and non-rhizosphere soils was determined. Changes in total bacteria and fungi community composition and structures using denaturing gradient gel electrophoresis (DGGE and sequencing were determined. Colony counts showed that B068150 colonization in the rhizosphere was significantly higher (p < 0.001 than in non-rhizosphere soils. Based on our data, the introduction of B. bacillus B068150 did not change the diversity of microbial communities significantly in the rhizosphere of three soils. Our data showed that population density of B068150 in clay soil had a significant negative correlation on bacterial diversity in cucumber rhizosphere in comparison to loam and sandy soils, suggesting that the impact of B068150 might be soil specific.

  12. 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.

  13. Cold-acclimation increases the predatory efficiency of the aphidophagous coccinellid Adalia bipunctata

    DEFF Research Database (Denmark)

    Sørensen, Christian Hougaard; Toft, Søren; Kristensen, Torsten Nygård

    2013-01-01

    a heat knock down assay as well as the effects of rearing temperature on pupal survival and adult mass. We demonstrate that ladybirds acclimated to a certain temperature consume more aphids at that temperature than ladybirds acclimated to other temperatures. Acclimating ladybirds to cold temperatures...... thermal regimes. Here, we report on the effects of rearing temperature (15, 20 and 25 °C) of A. bipunctata on aphid predation at similar test temperatures and under cold semi-natural conditions. Furthermore we assessed the upper thermal critical limit of ladybirds from the three rearing temperatures using...... also increased their body-size but reduced pupal survival and heat resistance, suggesting costs associated with acclimation. Our findings have implications for the application of ladybirds as bio-control agents in different thermal environments. The results can be used to improve the efficiency of pest...

  14. 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. PMID:26873560

  15. 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. PMID:24277414

  16. Screening of Pseudomonas sp. Isolated from Rhizosphere of Soybean Plant as Plant Growth Promoter and Biocontrol Agent

    Directory of Open Access Journals (Sweden)

    Aris T. Wahyudi

    2011-01-01

    Full Text Available Problem statement: Pseudomonas spesies are one of the rihizobacterial group that have an important role in plant growth promoter and plant health. To prepare them as inoculants, they must have a range of characters as growth promoter such as Indole Acetic Acid (IAA producers which can promote the growth of plants and solubilize phosphates. In addition, they must also have the various characters that act as biocontrol agents such as siderofor, chitinase and anti-fungal compound producers. Approach: Pseudomonas sp isolated from soybeans rhizospere and identified based on physiological reactions and 16S rRNA gene sequences. Various tests for the determination of the growth promoter were based on IAA production, phosphate solubilization and growth promoter of length of root and stems and number of lateral roots of soybean sprouts. Test of siderophore, chitinase, as well as anti anti-fungal compounds productions to inhibit the growth of Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii, were used as a biocontrol agent determination. Hypersensitivity test was used to screen for Pseudomonas sp classified as non-pathogenic rhizobacteria. Results: Fourteen isolates identified as a non-pathogenic Pseudomonas sp that produced IAA and Promoted enhancement of root length, shoot length, or number of lateral root. Among those 14 isolates, 8 isolates showed phosphate solubilizing activity, 12 isolates capable of producing siderophore and six isolates were observed to have chitinolytic activity. Only three isolates were able to inhibit the growth of Fusarium oxysporum in high level. While one and two isolates inhibited Sclerotium rolfsii and Rhizoctonia solani in high level, respectively. Conclusion: On the basis of excellent growth promoter and biocontrol activities, we recommended 5 isolates of Pseudomonas sp which were Crb-3, Crb-16, Crb-17, Crb-44 and Crb-94 as potential isolates of Pseudomonas sp that could be applied as

  17. 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. PMID:25023078

  18. New solid-state fermentation chamber for bulk production of aerial conidia of fungal biocontrol agents on rice.

    Science.gov (United States)

    Ye, S D; Ying, S H; Chen, C; Feng, M G

    2006-06-01

    A novel solid-state fermentation apparatus, namely an upright multi-tray conidiation chamber, was developed to facilitate the production of aerial conidia of fungal biocontrol agents, such as Beauveria bassiana. The chamber with 25 bottom-meshed metal trays had a capacity of > or =50 kg rice with each tray holding > or =2 kg. In repeated trials, a mean yield of 2.4 (1.8-2.7) x 10(12) conidia kg(-1) rice was harvested from the 7-day cultures of B. bassiana in a fully loaded chamber. The new apparatus has a high potential for bulk production of fungal conidia. PMID:16786244

  19. 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

  20. 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.

  1. Killer yeasts as biocontrol agents of spoilage yeasts and bacteria isolated from wine

    Directory of Open Access Journals (Sweden)

    Fernández de Ullivarri Miguel

    2014-01-01

    Full Text Available During the winemaking process Saccharomyces cerevisiae is the main yeast species but other yeasts called non-Saccharomyces as well as different species of lactic acid bacteria (LAB are also present. Then, one strategy to prevent or reduce microbial contamination during the winemaking process is the use of killer yeasts. The aim of this study was to evaluate the killer activity (KA of autochthonous yeasts from Northwest region of Argentine (S. cerevisiae Cf8 and Wickerhamomyces anomalus Cf20 on spoilage yeasts and in LAB of the wine. The KA was evaluated using cell-free supernatants obtained from pure and mixed cultures of strains Cf8-Cf20. S. cerevisiae Cf8 showed a growth reduction between 7 and 48% on D. anomala BDa15, P. membranifaciens BPm481 and Z. bailii Bzb317 while W. anomalus Cf20 exhibited KA of 20, 61, 91 and 92% against B. bruxellensis Ld1, D. anomala BDa15, P. membranifaciens BPm481 and P. guilliermondii Cd6, respectively. Killer mixed supernatants showed growth inhibition similar to strain Cf20. Screening against LAB showed that both killer toxins were able to inhibit the growth of L. hilgardii 5w as well as to reduce a 16–31% histamine production by this LAB strain. These results confirm the potential of autochthonous killer yeasts as biocontrol agents in winemaking process. The mixed culture S. cerevisiae Cf8-W. anomalus Cf20 presented a wide range of KA on spoilage yeasts as well as on L. hilgardii. Therefore, the use of killer yeasts as starter cultures would allow producing wines with controlled quality.

  2. 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. PMID:27092128

  3. Biocontrol efficacy and plant growth promoting activity of Bacillus altitudinis isolated from Darjeeling hills, India.

    Science.gov (United States)

    Sunar, Kiran; Dey, Pannalal; Chakraborty, Usha; Chakraborty, Bishwanath

    2015-01-01

    A total of 18 bacterial isolates were obtained from the rhizosphere of Sechium edule growing in the lower foothills of Darjeeling, India. The bacterial isolates were tested for PGPR traits in vitro such as phosphate solubilization, HCN, siderophore, IAA, chitinase, protease production as well as inhibition of pthytopathogens. Of all the bacterial isolates, one bacterium designated as BRHS/S-73 was found to possess all the tested characters which was identified on the basis of 16S rRNA gene sequence analysis as Bacillus altitudinis and was selected for in vivo studies. A significant improvement in growth measured in terms of increase in root length, shoot length, and increase in root and shoot biomass was observed when seeds of Vigna radiata, Cicer arietinum, and Glycine max were bacterized prior to sowing in field condition. Besides, the bacterium could also solubilize soil phosphate. Apart form growth promotion, root rot disease of Vigna radiata caused by Thanatephorus cucumeris was also significantly reduced by 74% when the bacterium was applied to the rhizosphere prior to pathogen challenge. The biocontrol efficacy of the bacterium was found to be 66.6% even after 30 days of pathogen inoculation. Activities of key defense related enzymes such as phenylalanine ammonia lyase, peroxidase, β-1,3-glucanase, and chitinase in both roots and leaves of treated plants were also enhanced. Results clearly suggest that B. altitudinis (BRHS/S-73) is a potential PGPR which can be used as efficient microorganism for enhancement of plant growth and suppression of fungal disease. PMID:23996212

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

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    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.

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

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    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.

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

    Science.gov (United States)

    Zhang, Shujian; Chakrabarty, Pranjib K; Fleites, Laura A; Rayside, Patricia A; Hopkins, Donald L; Gabriel, Dean W

    2015-01-01

    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. PMID:26218423

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

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    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

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

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    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.

  9. 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. PMID:25700743

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

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    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.

  11. Screening of bacterial biocontrols against sapstain fungus (Lasiodiplodia theobromae Pat.) of rubberwood (Hevea brasiliensis Muell.Arg.).

    Science.gov (United States)

    Sajitha, K L; Maria Florence, E J; Dev, Suma Arun

    2014-09-01

    Diverse bacterial biocontrol agents from various sources of aerobic composts against the sapstain fungus Lasiodiplodia theobromae in rubberwood (Hevea brasiliensis) were isolated, screened and identified by various morphological, biochemical and molecular techniques. The inhibitory effect of seventeen bacterial isolates was examined and seven exhibited inhibition towards the sapstain fungus. Among the seven antagonists, six were conclusively identified as Bacillus subtilis and one as Paenibacillus polymyxa using 16S rRNA-encoding gene sequencing. This is the first report on the occurrence of P. polymyxa, a potent biofertilizer and antagonist in vermicompost. HiCrome Bacillus agar was identified as an effective medium for differentiation of B. subtilis from other Bacillus species. The present work demonstrates the efficacy of the antagonistic property of B. subtilis strains against rubberwood sapstain fungus. Culture-based antagonistic inhibition displayed by B. subtilis can be extended to cater to the biocontrol requirements of wood-based industries against the stain fungus. The study showed the utility of an integrated approach, employing morphological, biochemical and molecular tools for conclusive identification of several bacterial isolates present in aerobic composts from diverse sources. PMID:25049165

  12. Antifungal modes of action of Saccharomyces and other biocontrol yeasts against fungi isolated from sour and grey rots.

    Science.gov (United States)

    Nally, M C; Pesce, V M; Maturano, Y P; Rodriguez Assaf, L A; Toro, M E; Castellanos de Figueroa, L I; Vazquez, F

    2015-07-01

    The aim of this study was to determine the putative modes of action of 59 viticultural yeasts (31 Saccharomyces and 28 non-Saccharomyces) that inhibited fungi isolated from sour and grey rot in grapes. Inhibition of fungal mycelial growth by metabolites, enzyme activities (laminarinases, chitinases), antifungal volatiles, competition for nutrients (siderophores, Niche Overlap Index (NOI)), inhibition of fungal spore germination and decreased germinal tube length and induction of resistance were assayed. Biofungicide yeasts were classified into "antifungal patterns", according to their mechanisms of action. Thirty isolates presented at least two of the mechanisms assayed. We propose that inhibition of fungal mycelial growth by metabolites, laminarinases, competition for nutrients, inhibition of fungal spore germination and decreased germinal tube length, and antifungal volatiles by Saccharomyces and non-Saccharomyces viticultural yeasts is used as putative biocontrol mechanisms against phytopathogenic fungi. Twenty-four different antifungal patterns were identified. Siderophore production (N)and a combination of siderophore production and NOI>0.92 (M)were the most frequent antifungal patterns observed in the biofungicide yeasts assayed. Elucidation of these mechanisms could be useful for optimization of an inoculum formulation, resulting in a more consistent control of grey and sour rot with Saccharomyces and non-Saccharomyces biocontrol yeasts. PMID:25863340

  13. Cow dung extract: a medium for the growth of pseudomonads enhancing their efficiency as biofertilizer and biocontrol agent in rice.

    Science.gov (United States)

    Srivastava, Rashmi; Aragno, Michel; Sharma, A K

    2010-09-01

    Some pseudomands are being utilized as biofertilizers and biopesticides because of their role in plant growth promotion and plant protection against root parasites, respectively. Two strains of Pseudomonas, P. jessenii LHRE62 and P. synxantha HHRE81, recovered from wheat rhizosphere, have shown their potential in field bioinoculation tests under rice-wheat and pulse-wheat rotation systems. Normally, pseudomonads are cultivated on synthetic media-like King's B and used for inoculation on seeds/soil drench with talcum or charcoal as carrier material. Cow dung is being used for different purposes from the ancient time and has a significant role in crop growth because of the content in humic compounds and fertilizing bioelements available in it. Here, cow dung extract was tested as a growth medium for strains LHRE62 and HHRE81, in comparison with growth in King's B medium. The log phase was delayed by 2 h as compared to growth in King's B medium. The bacterial growth yield, lower in plain cow dung extract as compared to King's B medium, was improved upon addition of different carbon substrates. Growth of rice var. Pant Dhan 4 in pot cultures was increased using liquid formulation of cow dung extract and bacteria as foliar spray, compared to their respective controls. Biocontrol efficacy of the bioagents was assessed by challenging rice crop with Rhizoctonia solani, a sheath blight pathogen. The growth promotion and biocontrol efficiencies were more pronounced in the case of mixed inocula of strains LHRE62 and HHRE81. PMID:23100852

  14. Transaldolase gene Tal67 enhances the biocontrol activity of Clonostachys rosea 67-1 against Sclerotinia sclerotiorum.

    Science.gov (United States)

    Liu, Jing-Yu; Li, Shi-Dong; Sun, Man-Hong

    2016-06-01

    Clonostachys rosea is a promising biocontrol agent that parasitizes various fungal plant pathogens. In this paper, transaldolase gene Tal67 was found to be greatly upregulated in C. rosea isolate 67-1 during mycoparasitism of Sclerotinia sclerotiorum sclerotia. Quantitative real-time PCR revealed a significant increase in expression at 0-48 h after induction by sclerotia, and the level peaked at 13.9-fold higher than the control at 24 h. Gene disruption led to a decrease in the growth rate of the Tal67-deficient strain ΔTal67 to 5.3 mm/day, which was much lower than the wild type and the complemented strain ΔTal67+ (P Botrytis cinerea was 15.8% lower than the wild type, and the parasitic rate to S. sclerotiorum decreased by 24.6%. However, reinsertion of the transaldolase gene recovered the fungicidal activity of C. rosea. The efficacy of the mutants against soybean Sclerotinia stem rot was evaluated in the greenhouse, and the control efficiency of isolate 67-1 reached 65.3%, while the efficiency of the ΔTal67 strain decreased sharply to 17.8%, and the complemented strain ΔTal67+ recovered to 64.8%. These results suggest that Tal67 plays an important role in the growth and biocontrol activity of C. rosea. PMID:27130824

  15. 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 rape stem rot, promoted growth and increased yield compared to the control and exceeded, at dose 100%, the action of the fungicide procymidone(®). In conclusion, the mutant pt361 of P. lilacinus is a novel and promising biocontrol agent against oilseed rape Sclerotinia stem rot. PMID:26521137

  16. 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.

  17. 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.

  18. 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 reduci...

  19. MUTATION OF A DEGS HOMOLOG IN ENTEROBACTER CLOACAE DECREASES SEED AND ROOT COLONIZATION BUT DOES NOT AFFECT BIOCONTROL OF DAMPING-OFF CAUSED BY PYTHIUM ULTIMUM ON CUCUMBER

    Science.gov (United States)

    Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops. E. cloacae strain C10 is a mini-Tn5 Km transposon mutant of strain 501R3. Strain C10 was reduced in colonization of cucumber, sunflower, and pea seeds, but unaffecte...

  20. 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.

  1. Evaluation of yeasts obtained from Antarctic soil samples as biocontrol agents for the management of postharvest diseases of apple (Malus x domestica)

    Science.gov (United States)

    Psychrotrophic yeasts isolated from soils collected in Antarctica and selected by its capacity of growing in apple juice at low temperatures were evaluated for their potential as biocontrol agents for the management of postharvest diseases of apple during cold storage. Among the species recovered, ...

  2. RNA interference of endochitinases in the sugarcane endophyte Trichoderma virens 223 reduces its fitness as a biocontrol agent of pineapple disease.

    Science.gov (United States)

    Romão-Dumaresq, Aline S; de Araújo, Welington Luiz; Talbot, Nicholas J; Thornton, Christopher R

    2012-01-01

    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. PMID:23110120

  3. 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

    2016-01-01

    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. PMID:27103342

  4. 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....

  5. 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

    2016-01-01

    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. PMID:27103342

  6. 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...

  7. Draft Genome Sequence of Cryptococcus flavescens Strain OH182.9_3C, a Biocontrol Agent against Fusarium Head Blight of Wheat

    OpenAIRE

    Rong, Xiaoqing; McSpadden Gardener, Brian B.

    2013-01-01

    Cryptococcus flavescens strain OH182.9_3C (3C) is a novel biopesticidal agent that can be used to control fusarium head blight of wheat. Here we present the draft genome sequence for 3C, the first for the species C. flavescens. Additionally, several genes that may contribute to the biocontrol activities of 3C were identified in silico.

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. Detection and quantification by PCR assay of the biocontrol agent Pantoea agglomerans CPA-2 on apples.

    Science.gov (United States)

    Soto-Muñoz, Lourdes; Teixidó, Neus; Usall, Josep; Viñas, Inmaculada; Torres, Rosario

    2014-04-01

    The registration of biological control agents requires the development of monitoring systems to detect and quantify the agent in the environment. Pantoea agglomerans CPA-2 is an effective biocontrol agent for postharvest diseases of citrus and pome fruits. The monitoring of CPA-2 in postharvest semi-commercial trials was evaluated by Rodac impression plates and the colonies isolated were confirmed by conventional PCR using the SCAR primers PAGA1 and PAGB1. Samples were taken from different surfaces that had contact with CPA-2, the surrounding environment and working clothes worn by handlers. Moreover, population dynamics of the strain CPA-2 were determined on apple surfaces using both the classical plating technique and real-time quantitative PCR (qPCR). A qPCR assay using a 3'-minor groove-binding (MGB) probe was developed for the specific detection and quantification of P. agglomerans strain CPA-2. Based on the nucleotide sequence of a SCAR fragment of CPA-2, one primer set and TaqMan MGB probe were designed. The primers SP2-F/SP2-R and the TaqMan MGB probe showed a specific detection of strain CPA-2 on apple surfaces, which was verified tested against purified DNA from 17 strains of P. agglomerans, 4 related Pantoea species, and 21 bacterial strains from other genera isolated from whole and also freshly-cut fruit and vegetables. The detection level was approximately 10(3) cells per reaction, and the standard curve was linear within a range of 5log units. Results from semi-commercial trials showed that CPA-2 had a low impact. The maximum persistence of P. agglomerans CPA-2 was not longer than 5days in plastic boxes stored at 0°C. Significant differences in CPA-2 population level dynamics were observed in results obtained by qPCR and dilution plating. These differences may indicate the presence of non-degraded DNA from non-viable cells. In conclusion, qPCR is a novel potential tool to quickly and specifically monitor recent surface colonisation by CPA-2

  14. Seleção de bactérias endofíticas de tomateiro como potenciais agentes de biocontrole e de promoção de crescimento Screening of endophytic bacteria isolated from tomato plants as potencial biocontrol agents and growth promotion

    Directory of Open Access Journals (Sweden)

    Patrícia Baston Barretti

    2009-01-01

    Full Text Available Quarenta isolados bacterianos endofíticos de plantas sadias de tomateiro foram avaliados quanto à sua potencialidade como agentes de biocontrole de doenças do tomateiro. Foi realizada, em casa de vegetação, uma seleção massal utilizando-se Pseudomonas syringae pv. tomato e Alternaria solani, como patógenos desafiantes. Com base na média do número de lesões por planta, quatro isolados foram selecionados como potenciais agentes de biocontrole dessas enfermidades fúngica e bacteriana do tomateiro. Esses isolados foram identificados, por meio do sequenciamento do gene 16S do DNA ribossômico, como Acinetobacter johnsonii (UFV-E05, Serratia marcescens (UFV-E13, Sinorhizobium sp. (UFV-E25 e Bacillus megaterium (UFV-E26. Os mesmos isolados selecionados para o biocontrole também foram avaliados quanto à sua capacidade de promover o crescimento em plantas e somente S. marcescens (UFV-E13 proporcionou aumento na altura das plantas.Forty isolates of endophytic bacteria obtained from healthy tomato plants were tested for their potential as biocontrol agents of tomato diseases. A massal screening was performed at greenhouse using Pseudomonas syringae pv. tomato and Alternaria solani as challenging pathogens. Based on the average number of lesions per plant, four isolates were selected as potential agents of biocontrol of these tomato diseases caused by fungi and bacteria. These isolates were identified by 16S ribosomal DNA sequence analysis as Acinetobacter johnsonii (UFV-E05, Serratia marcescens (UFV-E13, Sinorhizobium sp. (UFV-E25 and Bacillus megaterium (UFV-E26. The four endophytes selected for biocontrol were also evaluated for their ability of promoting plant growth and only S. marcescens (UFV-E13 presented increase in the height of the plants.

  15. 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

  16. 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

  17. 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

  18. 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. PMID:27407296

  19. Peptaibol, Secondary‐Metabolite, and Hydrophobin Pattern of Commercial Biocontrol Agents Formulated with Species of the Trichoderma harzianum Complex

    DEFF Research Database (Denmark)

    Degenkolb, Thomas; Nielsen, Kristian Fog; Dieckmann, Ralf;

    2015-01-01

    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...

  20. 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.

  1. 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. PMID:26466874

  2. Potencial de la cepa CPA-8 de Bacillus subtilis como agente de biocontrol de enfermedades de postcosecha de fruta

    OpenAIRE

    Yánez Mandizábal, Viviana del Rocío

    2012-01-01

    La limitació en l’ús de fungicides per al control de malalties en postcollita de fruita és una problemàtica d’elevada magnitud en el sector fructícola actual. Degut a això l’ús d’estratègies alternatives com el control biològic microbià són fonamentals per a la producció de fruita de qualitat. Malgrat tot, el desenvolupament de programes de biocontrol eficaços requereix d’un coneixement profund de la capacitat de control i els mecanismes d’acció utilitzats per l’agent microbià ...

  3. In-vitro evaluation of fungicides, plant extracts and bio-control agents against rice blast pathogen magnaporthe oryzae couch

    International Nuclear Information System (INIS)

    Among 5 fungicides viz., Thiophanate-methyl, Carbendazim, Fosetyl-aluminium, Mancozeb and Copper oxychloride, used against the Magnaporthe oryzae, only Mancozeb appeared as the highly effective fungicide that completely inhibited the mycelial growth of the fungus. All other fungicides showed little effect at higher concentrations. The extracts of garlic (Allium sativum L.), neem (Azadirachta indica L.) and calatropis (Calotropis procera L.) when used against M. oryzae by food poisoning method, only higher dose of garlic completely inhibited the mycelial growth of the test fungus. Six bio-control agents viz., Trichoderma harzianum, Trichoderma polysporum, Trichoderma pseudokoningii, Gliocladium virens, Paecilomyces variotii and Paecilomyces lilacinus were used. Maximum mycelial inhibition of M. oryzae was provided by P. lilacinus followed by Trichoderma spp. (author)

  4. 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. PMID:26445226

  5. Chitinase production by Bacillus subtilis ATCC 11774 and its effect on biocontrol of Rhizoctonia diseases of potato.

    Science.gov (United States)

    Saber, Wesam I A; Ghoneem, Khalid M; Al-Askar, Abdulaziz A; Rashad, Younes M; Ali, Abeer A; Rashad, Ehsan M

    2015-12-01

    Stem canker and black scurf of potato, caused by Rhizoctonia solani, can be serious diseases causing an economically significant damage. Biocontrol activity of Bacillus subtilis ATCC 11774 against the Rhizoctonia diseases of potato was investigated in this study. Chitinase enzyme was optimally produced by B. subtilis under batch fermentation conditions similar to those of the potato-growing soil. The maximum chitinase was obtained at initial pH 8 and 30 °C. In vitro, the lytic action of the B. subtilis chitinase was detected releasing 355 μg GlcNAc ml⁻¹ from the cell wall extract of R. solani and suggesting the presence of various chitinase enzymes in the bacterial filtrate. In dual culture test, the antagonistic behavior of B. subtilis resulted in the inhibition of the radial growth of R. solani by 48.1% after 4 days. Moreover, the extracted B. subtilis chitinase reduced the growth of R. solani by 42.3% when incorporated with the PDA plates. Under greenhouse conditions, application of a bacterial suspension of B. subtilis at 109 cell mL⁻¹ significantly reduced the disease incidence of stem canker and black scurf to 22.3 and 30%, respectively. In addition, it significantly improved some biochemical parameters, growth and tubers yield. Our findings indicate two points; firstly, B. subtilis possesses a good biocontrol activity against Rhizoctonia diseases of potato, secondly, the harmonization and suitability of the soil conditions to the growth and activity of B. subtilis guaranteed a high controlling capacity against the target pathogen. PMID:26616375

  6. 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

  7. 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.

  8. DegQ regulates the production of fengycins and biofilm formation of the biocontrol agent Bacillus subtilis NCD-2.

    Science.gov (United States)

    Wang, Peipei; Guo, Qinggang; Ma, Yinan; Li, Shezeng; Lu, Xiuyun; Zhang, Xiaoyun; Ma, Ping

    2015-09-01

    Bacillus subtilis NCD-2 is an excellent biocontrol agent for tomato gray mold and cotton soil-borne diseases. The fengycin lipopeptides serve as a major role in its biocontrol ability. A previous study revealed that insertion of degQ with the mini-Tn10 transposon decreased the antifungal activity of strain NCD-2 against the growth of Botrytis cinerea. To clarify the regulation of degQ on the production of fengycin, we deleted degQ by in-frame mutagenesis. Compared with the wild-type strain NCD-2, the degQ-null mutant had decreased extracellular protease and cellulase activities as well as antifungal ability against the growth of B. cinerea in vitro. The lipopeptides from the degQ-null mutant also had significantly decreased antifungal activity against B. cinerea in vitro and in vivo. This result was confirmed by the decreased fengycin production in the degQ-null mutant that was detected by fast protein liquid chromatography analysis. Quantitative reverse transcription PCR further demonstrated that degQ positively regulated the expression of the fengycin synthetase gene. In addition, the degQ-null mutant also had a flatter colony phenotype and significantly decreased biofilm formation ability relative to the wild-type strain. All of those characteristics from degQ-null mutant could be restored to the strain NCD-2 wild-type level by complementation of intact degQ in the mutant. Therefore, DegQ may be an important regulator of fengycin production and biofilm formation in B. subtilis NCD-2. PMID:26302846

  9. 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.

  10. Screening of Mutation High-Yielding Biocontrol Bacterium BJ1 by Ion Beam Irradiation and Effect of Controlling Fusarium oxysporum cucunerinum Disease

    International Nuclear Information System (INIS)

    BJ1 of Bacillus subtilis is an important biocontrol factor in control of fungus disease. In order to improve the antagonistic ability of the strain,and obtain high-efficiency strains, 12C6+ of different doses and linear energy transfer (LET) was used to irradiate the biocontrol bacterium BJ1. The optimum dose and LET of ion beam irradiation for the BJ1 are 200-400 Gy and 60 keV/μm,respectively. The antagonistic ability is increased by 2%-21%. The control effect of mutation to Fusarium oxysporum f. sp. cucunerinum is increased by 17.48% over that of BJ1, and mutation also has better plant growth-promoting effect. (authors)

  11. GUS and GFP transformation of the biocontrol strain Clonostachys rosea IK726 and the use of these marker genes in ecological studies

    DEFF Research Database (Denmark)

    Lübeck, M.; Knudsen, I.M.B.; Jensen, B.; Thrane, Ulf; Janvier, C.; Jensen, D.F.

    2002-01-01

    Marker genes were introduced in the biocontrol strain Clonostachys rosea IK726 (IBT 9371) as a tool for monitoring the strain in ecological studies. The beta-glucuronidase (GUS) reporter gene and a gene encoding the green fluorescent protein (GFP) were, in separate experiments, integrated into the...... genome of IK726 using the Hygromycin B (HygB) resistance gene as selective marker. In order to select GUS and GFP transformants that resembled the wildtype strain, growth rate, production of enzymes and of metabolites of four GUS positive and six GFP positive transformants were tested in vitro. In...... addition, the biocontrol efficacy against disease caused by seed-borne Fusarium culmorum was evaluated on barley grown in sand. Compared to the wildtype, two selected GUS and GFP transformants, IK726c5 and IK726d11, did not vary in physiological properties. Both maintained the ability to colonize barley...

  12. 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.

  13. DUAL EFFECT OF AZOSPIRILLUM EXOPOLYSACCHARIDES (EPS) ON THE ENHANCEMENT OF PLANT GROWTH AND BIOCONTROL OF BLAST (PYRICULARIA ORYZAE) DISEASE IN UPLAND RICE (VAR. ASD-19)

    OpenAIRE

    A. Arul Selvi; S. Kalai Arasu

    2014-01-01

    The dual effect of exopolysaccharides of pseudomonas isolates viz, A17, A-18, A-26 and A-37 and certain ISR inducing chemicals viz, Salicylic acid, Jasmonic acid and Azibenzolar on the enhancement of plant growth and bio-control against blast disease in upland rice crop was studied under in-vitro condition. It was observed that the application of EPS, collected from pseudomonas isolates, augmented the height of rice plant and reduced the blast disease incidence in upland r...

  14. In Vitro Evaluation Of Selected Plant Extracts As Biocontrol Agents Against Black Mold Aspergillus Niger Van Tieghem Of Onion Bulbs Allium Cepa L.

    OpenAIRE

    SAIFELDIN A. F. EL-NAGERABI; Awad H. M. Ahmed; ABDULKADIR E. ELSHAFIE

    2015-01-01

    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 ...

  15. Survival of the biocontrol agents Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116 on the spikes of barley in the field*

    OpenAIRE

    Xin ZHANG; 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 strai...

  16. RNA Interference of Endochitinases in the Sugarcane Endophyte Trichoderma virens 223 Reduces Its Fitness as a Biocontrol Agent of Pineapple Disease

    OpenAIRE

    Aline S Romão-Dumaresq; Welington Luiz Araújo; Nicholas J Talbot; Thornton, Christopher R.

    2012-01-01

    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 t...

  17. Survivorship and feeding preferences among size classes of outplanted sea urchins, Tripneustes gratilla, and possible use as biocontrol for invasive alien algae

    OpenAIRE

    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 Kāneʻohe Bay, Hawaiʻi: Acanthophora spicifera, Gracilaria salicornia, Eucheuma denticulatum and Kappaphycus clade B. Post-...

  18. Zoospore Homing and Infection Events: Effects of the Biocontrol Bacterium Burkholderia cepacia AMMDR1 on Two Oomycete Pathogens of Pea (Pisum sativum L.)

    OpenAIRE

    Heungens, K; Parke, J. L.

    2000-01-01

    Burkholderia cepacia AMMDR1 is a biocontrol agent that protects pea and sweet corn seeds from Pythium damping-off in field experiments. The goal of this work was to understand the effect of B. cepacia AMMDR1 on Pythium aphanidermatum and Aphanomyces euteiches zoospore homing events and on infection of pea seeds or roots. In vitro, B. cepacia AMMDR1 caused zoospore lysis, prevented cyst germination, and inhibited germ tube growth of both oomycetes. B. cepacia AMMDR1 also reduced the attractive...

  19. Physiological manipulation and formulation of the biocontrol yeast Pichia anomala for control of Penicillium verrucosum and ochratoxin A contamination of moist grain.

    OpenAIRE

    Mokiou, Stella; Magan, Naresh

    2008-01-01

    The major hurdle in the production of commercial biocontrol agents (BCAs) has been the lack of production of appropriate formulations. Of particular importance is the conservation of viability and ecological competence after application. With this in mind studies were conducted to develop formulations of P. anomala which would have these attributes. Cells were grown in molasses-based medium modified with proline to different water availability levels (0.98 and 0.96) which significantly increa...

  20. Loss of GltB Inhibits Biofilm Formation and Biocontrol Efficiency of Bacillus subtilis Bs916 by Altering the Production of γ-Polyglutamate and Three Lipopeptides

    Science.gov (United States)

    Luo, Chuping; Fang, Xianwen; Xiang, Yaping; Wang, Xiaoyu; Zhang, Rongsheng; Chen, Zhiyi

    2016-01-01

    Aims This study examined the contribution of GltB on biofilm formation and biocontrol efficiency of B. subtilis Bs916. Methods and Results The gltB gene was identified through a biofilm phenotype screen and a bioinformatics analysis of serious biofilm formation defects, and then a gltB single knockout mutant was constructed using homologous recombination. This mutant demonstrated severe deficits in biofilm formation and colonisation along with significantly altered production ofγ-polyglutamate (γ-PGA) and three lipopeptide antibiotics (LPs) as measured by a transcriptional analysis of both the wild type B. subtilis Bs916 and the gltB mutant. Consequently, the mutant strain retained almost no antifungal activity against Rhizoctonia solani and exhibited decreased biocontrol efficiency against rice sheath blight. Very few gltB mutant cells colonised the rice stem, and they exhibited no significant nutrient chemotaxis compared to the wild type B. subtilis Bs916. The mechanism underlying these deficits in the gltB mutant appears to be decreased significantly in production of γ-PGA and a reduction in the production of both bacillomycin L and fengycin. Biofilm restoration of gltB mutant by additionγ-PGA in the EM medium demonstrated that biofilm formation was able to restore significantly at 20 g/L. Conclusions GltB regulates biofilm formation by altering the production ofγ-PGA, the LPs bacillomycin L and fengcin and influences bacterial colonisation on the rice stem, which consequently leads to poor biocontrol efficiency against rice sheath blight. Significance and Impact of Study This is the first report of a key regulatory protein (GltB) that is involved in biofilm regulation and its regulation mechanism and biocontrol efficiency by B. subtilis. PMID:27223617

  1. 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. PMID:26520102

  2. TmkA, a Mitogen-Activated Protein Kinase of Trichoderma virens, Is Involved in Biocontrol Properties and Repression of Conidiation in the Dark

    OpenAIRE

    Mukherjee, Prasun K.; Latha, Jagannathan; Hadar, Ruthi; Horwitz, Benjamin A.

    2003-01-01

    Trichoderma virens is a mycoparasitic fungus used in biocontrol of soilborne plant pathogens. It inhibits or kills plant-pathogenic fungi through production of antifungal antibiotics and parasitism of hyphae and sclerotia. Conidiation, or the production of asexual spores, an inducible process triggered by light or nutrient stress, is an important trait in survival and also development of formulation products. In many fungi, signaling pathways, including mitogen-activated protein kinase (MAPK)...

  3. Biocontrol proteomics:Implication of the pentoses phosphates pathway in the antagonist effect of Pichia anomala against Botrytis cinerea on apple

    OpenAIRE

    Kwasiborski, Anthony; Renaut, Jenny; Lepoivre, Philippe; Jijakli, Haissam

    2011-01-01

    The growing interest of the consumers for the wholesome food and the protection of the environment as well as the development of resistant pathogens to pesticides, stimulate the interest of growers to apply biological control methods. Pichia anomala strain K was previously identified as an efficient biocontrol agent of the main apple pathogens, Botrytis cinerea and Penicillum expansum. Further study demonstrated the complexicity of the mode of action of P. anomala against B. cinerea. A cDNA-A...

  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

    OpenAIRE

    Paola Pereira; Andrea Nesci; Carlos Castillo; Miriam Etcheverry

    2011-01-01

    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 a...

  5. 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.

  6. Occurrence and impact of the root-rot biocontrol agent Phlebiopsis gigantea on soil fungal communities in Picea abies forests of northern Europe.

    Science.gov (United States)

    Menkis, Audrius; Burokienė, Daiva; Gaitnieks, Talis; Uotila, Antti; Johannesson, Hanna; Rosling, Anna; Finlay, Roger D; Stenlid, Jan; Vasaitis, Rimvydas

    2012-08-01

    The aim of this study was to assess belowground occurrence, persistence and possible impact of the biocontrol agent Phlebiopsis gigantea (Fr.) Jülich on soil fungi. Sampling of soil and roots of Picea abies (L.) H. Karst. was carried out at 12 P. gigantea-treated and five nontreated control sites representing 1- to 60-month-old clear-cuts and thinned forest sites in Finland and Latvia. The 454-sequencing of ITS rRNA from fine roots, humus and mineral soil resulted in 8626 high-quality fungal sequences. Phlebiopsis gigantea represented 1.3% of all fungal sequences and was found in 14 treated and nontreated sites and in all three substrates. In different substrates, the relative abundance of P. gigantea at stump treatment sites either did not differ significantly or was significantly lower than in nontreated controls. No significant correlation was found between the time elapsed since the tree harvesting and/or application of the biocontrol and abundance of P. gigantea in different substrates. In conclusion, the results demonstrate that P. gigantea occasionally occurs belowground in forest ecosystems but that stump treatment with the biocontrol agent has little or no impact on occurrence and persistence of P. gigantea belowground, and consequently no significant impact on soil fungi. PMID:22443512

  7. 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. PMID:25583341

  8. 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. PMID:26160009

  9. 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. PMID:21835878

  10. Characterization of the biosynthetic operon for the antibacterial peptide herbicolin in Pantoea vagans biocontrol strain C9-1 and incidence in Pantoea species.

    Science.gov (United States)

    Kamber, Tim; Lansdell, Theresa A; Stockwell, Virginia O; Ishimaru, Carol A; Smits, Theo H M; Duffy, Brion

    2012-06-01

    Pantoea vagans C9-1 is a biocontrol strain that produces at least two antibiotics inhibiting the growth of Erwinia amylovora, the causal agent of fire blight disease of pear and apple. One antibiotic, herbicolin I, was purified from culture filtrates of P. vagans C9-1 and determined to be 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine, also known as N(ß)-epoxysuccinamoyl-DAP-valine. A plasposon library was screened for mutants that had lost the ability to produce herbicolin I. It was shown that mutants had reduced biocontrol efficacy in immature pear assays. The biosynthetic gene cluster in P. vagans C9-1 was identified by sequencing the flanking regions of the plasposon insertion sites. The herbicolin I biosynthetic gene cluster consists of 10 coding sequences (CDS) and is located on the 166-kb plasmid pPag2. Sequence comparisons identified orthologous gene clusters in Pantoea agglomerans CU0119 and Serratia proteamaculans 568. A low incidence of detection of the biosynthetic cluster in a collection of 45 Pantoea spp. from biocontrol, environmental, and clinical origins showed that this is a rare trait among the tested strains. PMID:22504810

  11. Evaluation of antifungal activity of carbonate and bicarbonate salts alone or in combination with biocontrol agents in control of citrus green mold.

    Science.gov (United States)

    Zamani, M; Sharifi Tehrani, A; Ali Abadi, A Alizadeh

    2007-01-01

    The aim of this research was to determine if the attacks of green mold on orange could be reduced by edible salts alone or in combination with biocontrol agent. For this purpose toxicity to Pantoea digitatum and practical use of sodium carbonate (SC), sodium bicarbonate (SBC) and potassium carbonate, and potassium bicarbonate alone or in combination with antagonistic bacteria (Pseudomonas fluorescens isolate PN, Bacillus subtilis isolate VHN, Pantoea agglomerans isolate CA) to control green mold were determined. All were fungistatic. SC and SBC were equal and superior to the other salts for control of green mold on oranges inoculated 6h before treatment and were chosen for subsequent trails under cold storage conditions. The biocontrol agents were found completely tolerant to 3% sodium bicarbonate and sodium carbonate at room temperature; although their culturability was reduced by > 1000-fold after 60 min in 1% other salt solutions. Satisfactory results were also obtained with the combined treatment for control of green mold. A significant increase in biocontrol activity of all isolate was observed when combined with sodium carbonate and sodium bicarbonate. The treatments comprising CA combined with SB was as effective as fungicide treatment. Thus, use of sodium bicarbonate treatment at 3% followed by the antagonist P. agglomerans CA could be an alternative to chemical fungicides for control of green mold on oranges. PMID:18396809

  12. Fusarium oxysporum strains as biocontrol agents against Fusarium wilt: effects on soil microbial biomass and activity Linhagens de Fusarium oxysporum como agentes de biocontrole da murcha-de-Fusarium: efeitos na biomassa e atividade microbiana do solo

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    Raquel Ghini

    2000-01-01

    Full Text Available Before planning the large-scale use of nonpathogenic strains of Fusarium oxysporum as biocontrol agents of Fusarium wilt, their behaviour and potential impact on soil ecosystems should be carefully studied as part of risk assessment. The aim of this work was to evaluate the effects of antagonistic F. oxysporum strains, genetically manipulated (T26/6 or not (233/1, on soil microbial biomass and activity. The effects were evaluated, in North-western Italy, in two soils from different sites at Albenga, one natural and the other previously solarized, and in a third soil obtained from a 10-year-old poplar stand (Popolus sp., near Carignano. There were no detectable effects on ATP, fluorescein diacetate hydrolysis, and biomass P that could be attributed to the introduction of the antagonists. A transient increase of carbon dioxide evolution and biomass C was observed in response to the added inoculum. Although the results showed only some transient alterations, further studies are required to evaluate effects on specific microorganism populations.Antes do uso em larga escala de linhagens não-patogênicas de Fusarium oxysporum como agentes de biocontrole da murcha-de-Fusarium, o seu comportamento e seus impactos potenciais no solo devem ser estudados como parte da avaliação de riscos. O objetivo do presente trabalho foi avaliar os efeitos de linhagens antagonistas de F. oxysporum, geneticamente manipuladas (T26/6 ou não (233/1, na biomassa e atividade microbiana do solo. Os efeitos foram avaliados no noroeste da Itália em dois solos de Albenga, sendo um natural e outro previamente solarizado, e em um terceiro solo obtido numa plantação de 10 anos de Popolus sp., em Carignano. Não foram observados efeitos significativos na quantidade de ATP, hidrólise de diacetato de fluoresceina e biomassa P, após a introdução dos antagonistas. Um aumento transitório foi observado na evolução de dióxido de carbono e no carbono da biomassa em resposta

  13. Assessment of metabolic capacity of Trichoderma inhamatum Bol12 QD biocontrol on native strains of Phytophthora infestans in vitro

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    Puño Ramon

    2011-08-01

    Full Text Available Plant pathogen Phytophthora infestans is a cause of decreased crop yield of tomato, to control these losses, farmers use chemicals. This has consequences for the environment, human health and beneficial organisms in the ecosystem. The objective was to obtain and identify native isolates of Trichoderma spp. In soil planted with tomato Tlayacapan, Morelos (Mexico, Alternaria solani problems and Phytophthora infestans, also determine their antagonistic capacity in vitro. Trichoderma was isolated directly from soil by dilution in culture medium plate with potato dextrose agar (PDA. On the other side plate dilutions of yeast T. QD Bol12 inhamatum crops produced in batch for 30 days to compare the effectiveness of biocontrol. The filtered yeast inhibited mycelial growth kinetic of the agent in laboratory with the 1:2 dilution growth was 32.5% for the 1:4 dilution mycelial growth was 69.1% and finally to the dilution of 1:8 of the yeast biocontrol mycelium grew to 95.2%. To demonstrate the inhibitory activity on the pathogen in field crops, there were 3 L batch for four months. The application of three doses (undiluted, diluted 1:2 and 1:4 plus a control dilution water only was performed in a complete block design with four replications randomly with the tomato crop, belonging to the variety Santa Cruz Kada Gigante in the plots of the Academic Rural United Campesina Carmen Pampa. Statistical analysis by Duncan's test showed that the pure leaven reduce infection by Phytophthora infestans significantly in tomato. Appeared another tomato plant pathogen, Septoria lycopersici, in the course of fieldwork. We also evaluated the effect of the dose of yeast to this disease, and also noticed a significant reduction with all doses of yeast. These experiments demonstrated that the seeds of T. QD Bol12 inhamatum have biocontrol effect on the tomato crop. The antagonistic capacity was assessed using the cellophane and the kind of antagonism with the dual culture

  14. 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

  15. Biocontrol of Aspergillus species on peanut kernels by antifungal diketopiperazine producing Bacillus cereus associated with entomopathogenic nematode.

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    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.

  16. 三株生防酵母菌对Botrytis cinerea的抑菌作用研究%Study on antifungal activities of biocontrol yeasts against Botrytis cinerea

    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

  17. 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

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    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

  18. The Sensor Kinase GacS Negatively Regulates Flagellar Formation and Motility in a Biocontrol Bacterium, Pseudomonas chlororaphis O6

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    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.

  19. Biocontrol of Late Blight (Phytophthora capsici Disease and Growth Promotion of Pepper by Burkholderia cepacia MPC-7

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    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.

  20. Quantifying the associations between fungal endophytes and biocontrol-induced herbivory of invasive purple loosestrife (Lythrum salicaria L.).

    Science.gov (United States)

    David, Aaron S; Quiram, Gina L; Sirota, Jennie I; Seabloom, Eric W

    2016-01-01

    Fungal endophytes are one of several groups of heterotrophic organisms that associate with living plants. The net effects of these groups of organisms on each other and ultimately on their host plants depend in part on how they facilitate or antagonize one another. In this study we quantified the associations between endophyte communities and herbivory induced by a biological control in the invasive Lythrum salicaria at various spatial scales using a culture-based approach. We found positive associations between herbivory damage and endophyte isolation frequency and richness at the site level and weak, positive associations at the leaf level. Herbivory damage was more strongly influenced by processes at the site level than were endophyte isolation frequency and community structure, which were influenced by processes at the plant and leaf levels. Furthermore, endophytic taxa found in low herbivory sites were nested subsets of those taxa found at high herbivory sites. Our findings suggest that endophyte communities of L. salicaria are associated with, and potentially facilitated by, biocontrol-induced herbivory. Quantifying the associations between heterotrophic groups ultimately may lead to a clearer understanding of their complex interactions with plants. PMID:27091387

  1. 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. PMID:24813508

  2. 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. PMID:27498507

  3. 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.

  4. Biology and host preferences of Cryptorhynchus melastomae (Coleoptera: Curculionidae), a possible biocontrol agent for Miconia calvescens (Melastomataceae) in Hawaii.

    Science.gov (United States)

    Reichert, Elisabeth; Johnson, M Tracy; Chacón, Eduardo; Anderson, Robert S; Wheeler, Terry A

    2010-12-01

    The introduced plant Miconia calvescens (Melastomataceae) poses a grave threat to Hawaii's native ecosystems and biodiversity. One potential candidate for classical biological control is Cryptorhynchus melastomae (Coleoptera: Curculionidae: Cryptorhynchinae), a stem-boring weevil from Central and South America. This weevil feeds on M. calvescens in its native Costa Rica and has been successfully reared under greenhouse conditions. Comparison of its environmental conditions in Costa Rica with those in the Miconia infested areas of Hawaii indicates the latter is a suitable habitat for C. melastomae. C. melastomae has one or two generations per year. Adults feed on new stems, petioles, leaf buds, veins, and lamina, whereas larvae mine the stem until pupation. Adults appear to prefer saplings for oviposition and feeding. Under greenhouse conditions both adults and larvae can seriously damage and kill small M. calvescens. Preliminary host testing indicates that C. melastomae may be family specific on Melastomataceae. However, because Hawaii lacks native melastomes and has many other serious melastome weeds, a family specific insect may be suitable as a biocontrol agent in this case. PMID:22182550

  5. Conservation of bio-control agents in cotton, gossypium hirsutum l. field by food supplements for insect pests management

    International Nuclear Information System (INIS)

    The study reports the use of artificial food sprays to conserve the parasitoids and predators for the management of insect pests in cotton field. Cotton crop was treated with bio-control agents, Chrysoperla carnea and Trichogramma chilonis alongwith different food attractants such as Protein hydrolysate and sugar alone and in combination in a randomized complete block design. Each treatment was applied on one-acre field with three replications. Results showed that the chemicals tested helped in increasing the populations of beneficial insects including; C. carnea, T. chilonis and Orius spp., in the field. The populations of C. carnea and T. chilonis were found the highest in the combined treatment of protein hydrolysate and sugar as compared to other treatments where protein hydrolysate and sugar were used separately. However, the population of Orius spp. was higher in the treatment where only sugar solution was sprayed as food supplement. Consequently, incorporation of food supplements in the trial increased the establishment of natural enemies and subsequently the predation/ parasitism percentage enhanced on the insect pests of cotton. (author)

  6. 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

  7. 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

    OpenAIRE

    Marisol Vargas; Felipe Garrido; Nelson Zapata; Maritza Tapia

    2012-01-01

    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 culture...

  8. Evaluation of Some Biocontrol Agents/Antagonistic Microbes Against Pastule Development of Leaf Rust of Wheat Caused by Puccinia recondita f. sp. Tritici Roberge ex. Desmaz (Erikson and Henn D.M. Henderson

    Directory of Open Access Journals (Sweden)

    A. Sheroze

    2002-01-01

    Full Text Available Out of five biocontrol agents/antagonistic microbes viz., Verticillium lecanii, Paecilomyces fumosoroseus, Beauveria bassiana, Cladosporium cladosporiodes and Metarrhizium anisopliae, Beauveria bassiana proved the best in retarding the postulation/rust development in wheats. When the microbes tested alone against leaf rust development, B. bassiana proved excellent and in combination with Verticillium lecanii and Paecilomyces furnosoroseus. Although there was an increase in colony diameter after 2nd week but the pattern of growth was the same as after one week of incubation of bio-control agents application.

  9. 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

  10. Requirement of Simultaneous Assessment of Crystal- and Supernatant-Related Entomotoxic Activities of Bacillus thuringiensis Strains for Biocontrol-Product Development

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    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.

  11. Characterization of PhlG, a Hydrolase That Specifically Degrades the Antifungal Compound 2,4-Diacetylphloroglucinol in the Biocontrol Agent Pseudomonas fluorescens CHA0

    OpenAIRE

    Bottiglieri, Mélanie; Keel, Christoph

    2006-01-01

    The potent antimicrobial compound 2,4-diacetylphloroglucinol (DAPG) is a major determinant of biocontrol activity of plant-beneficial Pseudomonas fluorescens CHA0 against root diseases caused by fungal pathogens. The DAPG biosynthetic locus harbors the phlG gene, the function of which has not been elucidated thus far. The phlG gene is located upstream of the phlACBD biosynthetic operon, between the phlF and phlH genes which encode pathway-specific regulators. In this study, we assigned a func...

  12. 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; Ekelund, Flemming; Strandmark, Lisa Bjørnlund

    2009-01-01

    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......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...

  13. Biocontrol proteomics:Implication of the pentoses phosphates pathway in the antagonist effect of Pichia anomala against Botrytis cinerea on apple.

    OpenAIRE

    Kwasiborski, Anthony; Renaut, Jenny; Delaplace, Pierre; Lepoivre, Philippe; Jijakli, Haissam

    2011-01-01

    Pichia anomala strain K was previously identified as an efficient biocontrol agent of the apple pathogen, Botrytis cinerea. Further study demonstrated the complexicity of the mode of action of P. anomala against B. cinerea. A molecular study revealed implication of exo-β-1,3-glucanases in the mode of action of P. anomala but suggested implication of other factors. The present study aims to increase our knowledge of the mode of action of P. anomala strain Kh6 against B. cinerea using an in sit...

  14. Caracterización de películas biodegradables con la incorporación de un agente de biocontrol

    OpenAIRE

    TORREGROSA MORENO, BELÉN

    2016-01-01

    [ES] El control biológico es una de las alternativas más eficientes y prácticas a los fungicidas químicos para el control de enfermedades producidas por hongos en agricultura. Su aplicación práctica no ha tenido lugar en gran medida por la sensibilidad de los agentes de biocontrol (ABCs) a condiciones ambientales adversas, que dan lugar a variabilidad y poca reproducibilidad en los resultados. Se ha trabajado con el ABC Candida sake, una levadura efectiva en el control de enfer...

  15. Characterization of the Biosynthetic Operon for the Antibacterial Peptide Herbicolin in Pantoea vagans Biocontrol Strain C9-1 and Incidence in Pantoea Species

    OpenAIRE

    Kamber, Tim; Lansdell, Theresa A.; Stockwell, Virginia O.; Carol A Ishimaru; Smits, Theo H. M.; Duffy, Brion

    2012-01-01

    Pantoea vagans C9-1 is a biocontrol strain that produces at least two antibiotics inhibiting the growth of Erwinia amylovora, the causal agent of fire blight disease of pear and apple. One antibiotic, herbicolin I, was purified from culture filtrates of P. vagans C9-1 and determined to be 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine, also known as Nß-epoxysuccinamoyl-DAP-valine. A plasposon library was screened for mutants that had lost the ability to produce herbicolin I. It was sh...

  16. Do biopesticides affect the demographic traits of a parasitoid wasp and its biocontrol services through sublethal effects?

    Science.gov (United States)

    Biondi, Antonio; Zappalà, Lucia; Stark, John D; Desneux, Nicolas

    2013-01-01

    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-history variables

  17. Effectiveness of Lysiphlebus testaceïpes Cresson as biocontrol agent of Aphis gossypii Glover infesting pepper plants

    Directory of Open Access Journals (Sweden)

    M. Ben Halima Kamel

    2011-12-01

    Full Text Available In Tunisia, greenhouse crops are damaged by Aphis gossypii Glover and Myzus persicae Sulzer (Ben Halima Kamel 1991; Ben Halima Kamel and Ben Hamouda 1993, 1998. These aphids are considered to be the most dangerous pests of pepper because of their biology and biotic potential (Ben Halima Kamel 1991; Blackman and Eastop 2000. There are several ways of controlling these pests with chemical control being the most widely used. This method has more disadvantages than benefits (Gibson et al. 1982. The use of natural enemies to control aphids is an effective way of improving the yield and quality of protected crops. There are many studies on the following naturally occurring enemies of A. gossypii: Aphidius matricariae Haliday, Lysiphlebus fabarum Marshall, Aphidoletes aphidimyza (Rondani, Episyrphus balteatus (De Geer (Ben Halima Kamel and Ben Hamouda 1998 and Lysiphlebus testaceipes (Cresson (Ben Halima Kamel, unpublished data, 1999. It is now important to evaluate the effectiveness of L. testaceipes as a biocontrol agent of A. gossypii. This parasitoďd was introduced into the Mediterranean area (Carver and Franzmann 2001 and is thought to be an important parasite of A. gossypii (Lopes et al. 2007. The aim of this mainly laboratory study was to determine the factors affecting the establishment and success of a biological control agent, in particular the number of L. testaceďpes relative to the initial density of A. gossypii, needed to control the aphid. In addition, the effect of the L. testaceďpes on structure of A. gossypii populations was evaluated. Furthermore, the effectiveness of L. testaceipes in controlling A. gossypii infesting a protected crop of pepper plants and the subsequent effect on the growth of the pepper plants was also evaluated.

  18. Studies of plant colonisation by closely related Bacillus amyloliquefaciens biocontrol agents using strain specific quantitative PCR assays.

    Science.gov (United States)

    Johansson, Anna H; Bejai, Sarosh; Niazi, Adnan; Manzoor, Shahid; Bongcam-Rudloff, Erik; Meijer, Johan

    2014-12-01

    Certain strains of Bacillus amyloliquefaciens can colonize plants and improve growth and stress management. In order to study these effects, bacterial growth dynamics on plants and in the rhizosphere are of interest calling for specific analytical tools. For that purpose, quantitative real-time PCR (qPCR) assays were developed in order to differentiate among three closely related B. amyloliquefaciens subsp. plantarum strains (UCMB5033, UCMB5036, UCMB5113) and to determine their levels with high accuracy. Oligonucleotide primers were designed for strain unique gene sequences and used for SYBR green based qPCR analysis. Standard curves covered a wide linear range (10(6)) of DNA amounts with the lowest detection level at 50 fg. Post-reaction melting curve analysis showed only a single product. Accurate threshold cycles were obtained, even in the presence of high excess of related Bacillus strains and total bacterial DNA from soil. Analysis of Bacillus colonisation after seed treatment of two oilseed rape cultivars (Oase and Ritz) grown on agar support showed a time dependent effect but that the bacteria mostly were found on root tissues and little on green tissues. The colonisation on plants grown in soil varied among the Bacillus strains where Oase seemed to house more bacteria than Ritz. Applied as a mixture, all three Bacillus strains co-existed on the roots of plants grown in soil. The qPCR assay in combination with other techniques will be a powerful tool to study plant interactions of these B. amyloliquefaciens biocontrol agents to further understand the requirements for successful interactions and improvement of plant properties. PMID:25294724

  19. MULTI-TRAITS OF NON-PATHOGENIC FLUORESCENT PSEUDOMONAS AND EVALUATION OF THEIR POTENTIEL AS BIOCONTROL AGENTS

    Directory of Open Access Journals (Sweden)

    Mehri Inès

    2014-01-01

    Full Text Available In recent years, certain strains of fluorescent pseudomonads called PGPB have drawn attention due to their abilities to promote plant growth. Therefore, in this investigation, we have explored the adhesive properties, the phytostimulator effects and the biocontrol activities of 40 isolates, with the aim to select potential inoculants to improve crop yields. Ten different colony morphotypes were detected on CRA plates. PsTp172 described as “ST” showed the highest adherence ability to abiotic surface (OD550 = 2.102. 31 isolates were positive for the plant growth-promoting hormone (IAA production and 30 stains solubilised tri-calcium phosphate in Pikovskaya’s agar. Furthermore, the highest pyoverdine concentration was detected with PsTp172 strain (172.50 µM under iron starvation conditions. This strain also exhibited a co-resistance against Zn2+ and Mn2+ and displayed high values of Minimum Inhibitory Concentrations (MIC for each heavy metal. Additionally, among the tested isolates, eight strains (PsS15, PsTp172, PsS28, PsTp171, PsS31, PsS67, PsS18, PsS39 and PsS93 were found to be efficient antagonists against the 3 pathogenic strains and 6 isolates (PsS15, PsTp156, PsTp172, PsC54, PsTp171 and PsS102 were considered as lactone inhibitors of the 3 tested strains, as shown by their ability to inhibit the cellular communication. The majority of isolates showed various phytobeneficial traits and the most effective strains are P. putida (PsTp172 and PsS15 and P. mosseli (PsTp171.

  20. 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.

  1. Biosynthesis of Antibiotic Leucinostatins in Bio-control Fungus Purpureocillium lilacinum and Their Inhibition on Phytophthora Revealed by Genome Mining

    Science.gov (United States)

    Li, Erfeng; Mao, Zhenchuan; Ling, Jian; Yang, Yuhong; Yin, Wen-Bing; Xie, Bingyan

    2016-01-01

    Purpureocillium lilacinum of Ophiocordycipitaceae is one of the most promising and commercialized agents for controlling plant parasitic nematodes, as well as other insects and plant pathogens. However, how the fungus functions at the molecular level remains unknown. Here, we sequenced two isolates (PLBJ-1 and PLFJ-1) of P. lilacinum from different places Beijing and Fujian. Genomic analysis showed high synteny of the two isolates, and the phylogenetic analysis indicated they were most related to the insect pathogen Tolypocladium inflatum. A comparison with other species revealed that this fungus was enriched in carbohydrate-active enzymes (CAZymes), proteases and pathogenesis related genes. Whole genome search revealed a rich repertoire of secondary metabolites (SMs) encoding genes. The non-ribosomal peptide synthetase LcsA, which is comprised of ten C-A-PCP modules, was identified as the core biosynthetic gene of lipopeptide leucinostatins, which was specific to P. lilacinum and T. ophioglossoides, as confirmed by phylogenetic analysis. Furthermore, gene expression level was analyzed when PLBJ-1 was grown in leucinostatin-inducing and non-inducing medium, and 20 genes involved in the biosynthesis of leucionostatins were identified. Disruption mutants allowed us to propose a putative biosynthetic pathway of leucinostatin A. Moreover, overexpression of the transcription factor lcsF increased the production (1.5-fold) of leucinostatins A and B compared to wild type. Bioassays explored a new bioactivity of leucinostatins and P. lilacinum: inhibiting the growth of Phytophthora infestans and P. capsici. These results contribute to our understanding of the biosynthetic mechanism of leucinostatins and may allow us to utilize P. lilacinum better as bio-control agent. PMID:27416025

  2. 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.

  3. The major volatile compound 2-phenylethanol from the biocontrol yeast, Pichia anomala, inhibits growth and expression of aflatoxin biosynthetic genes of Aspergillus flavus.

    Science.gov (United States)

    Hua, Sui Sheng T; Beck, John J; Sarreal, Siov Bouy L; Gee, Wai

    2014-05-01

    Aspergillus flavus is a ubiquitous saprophyte that is able to produce the most potent natural carcinogenic compound known as aflatoxin B1 (AFB1). This toxin frequently contaminates crops including corn, cotton, peanuts, and tree nuts causing substantial economic loss worldwide. Consequently, more than 100 countries have strict regulations limiting AFB1 in foodstuffs and feedstuffs. Plants and microbes are able to produce volatile compounds that act as a defense mechanism against other organisms. Pichia anomala strain WRL-076 is a biocontrol yeast currently being tested to reduce AF contamination of tree nuts in California. We used the SPME-GC/MS analysis and identified the major volatile compound produced by this strain to be 2-phenylethanol (2-PE). It inhibited spore germination and AF production of A. flavus. Inhibition of AF formation by 2-PE was correlated with significant down regulation of clustering AF biosynthesis genes as evidenced by several to greater than 10,000-fold decrease in gene expression. In a time-course analysis we found that 2-PE also altered the expression patterns of chromatin modifying genes, MYST1, MYST2, MYST3, gcn5, hdaA and rpdA. The biocontrol capacity of P. anomala can be attributed to the production of 2-PE, which affects spore germination, growth, toxin production, and gene expression in A. flavus. PMID:24504634

  4. Biocontrol of Potato Common Scab is Associated with High Pseudomonas fluorescens LBUM223 Populations and Phenazine-1-Carboxylic Acid Biosynthetic Transcript Accumulation in the Potato Geocaulosphere.

    Science.gov (United States)

    Arseneault, Tanya; Goyer, Claudia; Filion, Martin

    2016-09-01

    Pseudomonads are often used as biocontrol agents because they display a broad range of mechanisms to control diseases. Common scab of potato, caused by Streptomyces scabies, was previously reported to be controlled by Pseudomonas fluorescens LBUM223 through phenazine-1-carboxylic acid (PCA) production. In this study, we aimed at characterizing the population dynamics of LBUM223 and the expression of phzC, a key gene involved in the biosynthesis of PCA, in the rhizosphere and geocaulosphere of potato plants grown under controlled and field conditions. Results obtained from controlled experiments showed that soil populations of LBUM223 significantly declined over a 15-week period. However, at week 15, the presence of S. scabies in the geocaulosphere was associated with significantly higher populations of LBUM223 than when the pathogen was absent. It also led to the detection of significantly higher phzC gene transcript numbers. Under field conditions, soil populations of LBUM223 followed a similar decline in time when a single inoculation was applied in spring but remained stable when reinoculated biweekly, which also led to greater phzC gene transcripts accumulation. Taken together, our findings suggest that LBUM223 must colonize the potato geocaulosphere at high levels (10(7) bacteria/g of soil) in order to achieve biocontrol of common scab through increased PCA production. PMID:27088392

  5. 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. PMID:27394000

  6. The effect of locust bean gum (LBG)-based edible coatings carrying biocontrol yeasts against Penicillium digitatum and Penicillium italicum causal agents of postharvest decay of mandarin fruit.

    Science.gov (United States)

    Parafati, Lucia; Vitale, Alessandro; Restuccia, Cristina; Cirvilleri, Gabriella

    2016-09-01

    Strains belonging to Wickerhamomyces anomalus, Metschnikowia pulcherrima and Aureobasidium pullulans species were tested in vitro as biocontrol agents (BCAs) against the post-harvest pathogenic molds Penicillium digitatum and Penicillium italicum. Moreover, studies aimed at screening the antifungal activity of selected yeast strains in vivo conditions against P. digitatum and P. italicum, and investigated the efficacy of a polysaccharidic matrix, locust bean gum (LBG), enriched with the tested BCAs, in controlling postharvest decays in artificially inoculated mandarins. The population dynamics of BCAs on wounds and the magnitude of peroxidase (POD) and superoxide dismutase (SOD) in fruit tissues were also investigated after treatments of mandarins with antagonistic yeasts. W. anomalus BS91, M. pulcherrima MPR3 and A. pullulans PI1 provided excellent control of postharvest decays caused by P. digitatum and P. italicum on mandarins, both when the yeasts were used alone and in combination with LBG, which enhanced the yeast cell viability over time. Finally, the increased activity of POD and lower decrease in SOD activity in response to BCAs application in mandarin fruits confirmed their involvement in the biocontrol mechanism. PMID:27217363

  7. Use of lablab (Lablab purpureus (L.) Sweet) for bio-control by native arthropods and its effect on yield of pumpkins.

    Science.gov (United States)

    Qureshi, S A; Angove, M; Wilkens, S; Midmore, D J

    2016-04-01

    Silverleaf whitefly (SLW, Bemisia tabaci MEAM1) and aphids are sap-sucking insects, which pose a serious threat to Australian cucurbit crops and the horticulture industry. Traditional chemical control for these insect pests is becoming less effective, and there is a need to search for alternative or supplementary methods. This study aimed to manipulate the habitat of pumpkin crops in a tropical setting (Queensland, Australia), by growing pumpkins (var. Japanese pumpkin) alone and between lablab (Lablab purpureus L. Sweet). It was hypothesized that the presence of lablab will increase the populations of natural enemies, and through their control of insect pests such as SLW and aphids, will affect pumpkin yield. The population of arthropods (natural enemies and pests of pumpkin), with a focus on SLW and aphids, were sampled weekly on both lablab and pumpkin crop for a total of 21 weeks. Results showed that lablab hosted more enemies of SLW per plant than pumpkin in either treatment. In addition, adult SLW numbers were significantly higher in the pumpkin-only crop compared with the pumpkin grown between lablab, while pumpkin in the mixed plantings had significantly more ladybirds and lacewing larvae (P < 0.05). While there was no significant difference in the average fruit weight between treatments, the total weight (kg) and number of marketable pumpkins per hectare was greater (P < 0.05) for the pumpkin/lablab treatment than the pumpkin-only treatment. This study shows that growing lablab alongside a pumpkin crop may enhance natural enemies of SLW and could significantly increase the yield. PMID:26693799

  8. 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 endoglucan......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...

  9. 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. PMID:26530991

  10. Environmental impact assessment of genetically modified biocontrol agents; La valutazione di impatto ambientale per gli antagonisti microbici geneticamente modificati. Come conciliare apprensione, razionalita' e sicurezza?

    Energy Technology Data Exchange (ETDEWEB)

    Migheli, Q. [Sassari Univ., Sassari (Italy). Dipt. di Protezione delle Piante

    2001-04-01

    This review summarises the theoretical basis of risk analysis, and the political and social implications of introducing new biotechnology products in agricultural environments. The main factors to be considered under the present European regulation in the environmental impact assessment of genetically modified biocontrol agents are briefly discussed. Finally, an alternative risk assessment paradigm is proposed for genetically modified microorganisms, which shall consider the intrinsic properties of each antagonist, rather than the method used for generating it. [Italian] In questo articolo sono presentati punti di vista politici e sociali nell'introduzione di nuovi prodotti biotecnologici nell'agricoltura. Vi sono affrontati anche i nuovi regolamenti europei in materia di agenti geneticamente modificati, stabilendo che gli antagonisti geneticamente modificati richiedono una ulteriore analisi del rischio associato alla modificazione genetica e che una volta stabilito che l'antagonista non arrechi rischi possa essere diffuso nell'ambiente.

  11. 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.

  12. The Pochonia chlamydosporia Serine Protease Gene vcp1 Is Subject to Regulation by Carbon, Nitrogen and pH: Implications for Nematode Biocontrol

    Science.gov (United States)

    Ward, Elaine; Kerry, Brian R.; Manzanilla-López, Rosa H.; Mutua, Gerald; Devonshire, Jean; Kimenju, John; Hirsch, Penny R.

    2012-01-01

    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. PMID:22558192

  13. 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.

  14. 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.

  15. “Integration of plant resistance, cropping practices, and biocontrol agents for enhancing disease management, yield efficiency, and biodiversity in organic European vineyards – VineMan.org” - FINAL PROJECT REPORT

    OpenAIRE

    Rossi, Vittorio

    2015-01-01

    The Project aimed at improving disease control, which is one of the main and most difficult tasks in organic viticulture, integrating plant resistance against pathogens, cropping practices, use of weather-driven disease models, and use of biocontrol agents (BCAs). All these aspects were firstly considered separately in each WP by the competent partners, then efforts were made to develop innovative vineyard management strategies that consider all these aspects. All plants have an innate imm...

  16. Impact of 2,4-Diacetylphloroglucinol-Producing Biocontrol Strain Pseudomonas fluorescens F113 on Intraspecific Diversity of Resident Culturable Fluorescent Pseudomonads Associated with the Roots of Field-Grown Sugar Beet Seedlings

    OpenAIRE

    Moënne-Loccoz, Yvan; Tichy, Hans-Volker; O'Donnell, Anne; Simon, Reinhard; O'Gara, Fergal

    2001-01-01

    The impact of the 2,4-diacetylphloroglucinol-producing biocontrol agent Pseudomonas fluorescens F113Rif on the diversity of the resident community of culturable fluorescent pseudomonads associated with the roots of field-grown sugar beet seedlings was evaluated. At 19 days after sowing, the seed inoculant F113Rif had replaced some of the resident culturable fluorescent pseudomonads at the rhizoplane but had no effect on the number of these bacteria in the rhizosphere. A total of 498 isolates ...

  17. 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.

  18. 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...

  19. Study on optimum growth condition and designing formulation for increasing shelf life of Streptomyces rimosus strain C-2012 as biocontrol agent

    Directory of Open Access Journals (Sweden)

    Ebrahim Karimi

    2015-12-01

    Full Text Available Introduction: An important issue in microbial biotechnology is linkage between screened beneficial strains in laboratory and industry. Therefore, to develop beneficial microbial biocontrol agents; optimization of nutritional and physiological condition for high level production and selection of carrier for final formulation are necessary. In this research we tried to find the best growth condition and suitable formulation for biocontrol Streptomyces rimosus strain C-2012. Materials and methods: For optimization of growth condition of strain C-2012, utilization of carbon sources, growth in different media, effect of temperature, pH and NaCl were investigated. Then the effect of different carriers and additives in final formulation and shelf life of microbial community were studied. Results: Study on utilization of carbon sources showed that glucose, fructose and mannitole were suitable carbon sources for growth and the best initial pH and temperature were 7 and 28°C, respectively. Results showed that the culture medium containing glucose, yeast extract and malt extract was the best medium. Investigation on NaCl effect showed that from 0 up to 300 mM sodium chloride could increase microbial community and salinity more than this range decreased microbial community. Based on the results we found that sand is suitable as microbial carrier comparing hydrogel polymers. Viability test during 36 months showed that formulation with NaCl content could keep 200 times (8*106 cfu/g more than samples without salinity at last month. Discussion and conclusion: Using suitable carbon sources such as glucose at 28 °C and pH at 7 are important items in optimum growth and preparing final formulation with good level of microbial community. Capability in secondary volatile and liquid metabolites production and fungal pathogen control by Streptomyces rimosus in the presence of NaCl showed that this strain has high potentiality to apply in both normal and saline area

  20. 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. PMID:22805919

  1. Production and characterization of rhamnolipids produced by Serratia rubidaea SNAU02 under solid-state fermentation and its application as biocontrol agent.

    Science.gov (United States)

    Nalini, S; Parthasarathi, R

    2014-12-01

    The present study aimed at exploring mahua (Madhuca indica) oil cake as a novel substrate for the production of biosurfactant by Serratia rubidaea SNAU02 under solid-state fermentation (SSF). Response surface methodology showed followings as the optimal conditions for the production of biosurfactant: mahua oil cake 7.48 g, 2.5 ml inoculum size (1×10(8) cells/ml), and pH 7.22 and 31 °C temperature. The characterization of the biosurfactant by TLC, FT-IR and GC-MS revealed the presence of rhamnolipid. The presence of rhamnosyl transferase gene responsible for biosynthesis of rhamnolipid was identified. The strain SNAU02 exhibited antifungal activity and demonstrated no toxicity against the seeds of Brassica oleracea and Artemia salina employed as a bio-indicator. The present findings indicated the potential of mahua oil cake as suitable substrate for the production of rhamnolipids in SSF by S. rubidaea SNAU02 and application potential of the biosurfactant produced as biocontrol agent against plant pathogens. PMID:25305653

  2. 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

  3. Modelling the effect of temperature, water activity and solute on the in vitro growth of the biocontrol yeast Pichia anomala strain K

    Directory of Open Access Journals (Sweden)

    Jijakli M.H.

    2008-01-01

    Full Text Available The objective of this work was to evaluate and model the combined effect of temperature (5-25°C and water activity (aw, 0.890-0.980 on Pichia anomala strain K growth and lag phase. Variance analysis showed a highly significant effect of aw, solute and temperature on strain K growth. The decrease of aw and temperature significantly reduced and delayed growth, the effect being more drastic with NaCl compared to the other solutes. Response surface models relating the natural logarithm of growth with aw and temperature were developed for each solute. Optimum growth was obtained at aw values ranging from 0.980 to 0.995 at 25°C. For all models, there was good agreement between observed and predicted values. However, only models based on sorbitol and glucose accurately described experimental growth data. Implementation of the present results in combination with our previous findings on four main post-harvest pathogens should result in a more effective biocontrol strategy to limit fruit losses

  4. Chitinolytic Streptomyces vinaceusdrappus S5MW2 isolated from Chilika lake, India enhances plant growth and biocontrol efficacy through chitin supplementation against Rhizoctonia solani.

    Science.gov (United States)

    Yandigeri, Mahesh S; Malviya, Nityanand; Solanki, Manoj Kumar; Shrivastava, Pooja; Sivakumar, G

    2015-08-01

    A chitinolytic actinomycete Streptomyces vinaceusdrappus S5MW2 was isolated from water sample of Chilika lake, India and identified using 16S rRNA gene sequencing. It showed in vitro antifungal activity against the sclerotia producing pathogen Rhizoctonia solani in a dual culture assay and by chitinase enzyme production in a chitin supplemented minimal broth. Moreover, isolate S5MW2 was further characterized for biocontrol (BC) and plant growth promoting features in a greenhouse experiment with or without colloidal chitin (CC). Results of greenhouse experiment showed that CC supplementation with S5MW2 showed a significant growth of tomato plants and superior disease reduction as compared to untreated control and without CC treated plants. Moreover, higher accumulation of chitinase also recovered in the CC supplemented plants. Significant effect of CC also concurred with the Analysis of Variance of greenhouse parameters. These results show that the a marine antagonist S5MW2 has BC efficiency against R. solani and chitinase enzyme played important role in plant resistance. PMID:25982747

  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. 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. PMID:24861342

  7. Biocontrol potential of Lariophagus distinguendus (Hymenoptera: Pteromalidae) against Sitophilus granarius (Coleoptera: Curculionidae) at low temperatures: reproduction and parasitoid-induced mortality.

    Science.gov (United States)

    Hansen, Lise Stengård

    2007-06-01

    Lariophagus distinguendus Forster (Hymenoptera: Pteromalidae) has been suggested as a biological control agent against the granary weevil, Sitophilus granarius (L.), in grain stores. Information on the effect of low temperatures prevailing in grain stores is necessary to be able to predict the potential of this parasitoid against S. granarius in temperate regions, where grain is cooled with ambient air to achieve safe storage conditions. The influence of constant temperatures of 16, 18, and 20 degrees C on life table parameters and parasitoid-induced mortality (PIM) was investigated in the laboratory. L. distinguendus is able to develop and reproduce at temperatures as low as 16 degrees C. The intrinsic rate of natural increase, rm, was 0.0182, 0.0222, and 0.0792 d(-1) at 16, 18, and 20 degrees C, respectively. The proportion of hosts killed due to parasitoid-induced mortality was highest at 20 degrees C. At this temperature, 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 degrees C; its development is quicker than that of its host, estimated from the literature; and it kills many hosts in addition to those used for reproduction. PMID:17598568

  8. Zoospore homing and infection events: effects of the biocontrol bacterium Burkholderia cepacia AMMDR1 on two oomycete pathogens of pea (Pisum sativum L.).

    Science.gov (United States)

    Heungens, K; Parke, J L

    2000-12-01

    Burkholderia cepacia AMMDR1 is a biocontrol agent that protects pea and sweet corn seeds from Pythium damping-off in field experiments. The goal of this work was to understand the effect of B. cepacia AMMDR1 on Pythium aphanidermatum and Aphanomyces euteiches zoospore homing events and on infection of pea seeds or roots. In vitro, B. cepacia AMMDR1 caused zoospore lysis, prevented cyst germination, and inhibited germ tube growth of both oomycetes. B. cepacia AMMDR1 also reduced the attractiveness of seed exudates to Pythium zoospores to nondetectable levels. However, when present at high levels on seeds, B. cepacia AMMDR1 had little net effect on zoospore attraction, probably because it also enhanced seed exudation. Seed-applied B. cepacia AMMDR1 dramatically reduced the incidence of infection by Pythium zoospores in situ compared with an antibiosis-deficient Tn5 mutant strain. This mutant strain also decreased Pythium infection incidence to some extent, but only when the pathogen inoculum potential was low. B. cepacia AMMDR1 did not affect attraction of Aphanomyces zoospores or Aphanomyces root rot incidence. These results suggest that B. cepacia AMMDR1 controls P. aphanidermatum largely through antibiosis, but competition for zoospore-attracting compounds can contribute to the effect. Differences in suppression of Aphanomyces and Pythium are discussed in relation to differences in the ecology of the two pathogens. PMID:11097889

  9. 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 (Pdamping-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 (Pseed-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. PMID:23920229

  10. The plant pathogenic fungus Gaeumannomyces graminis var. tritici improves bacterial growth and triggers early gene regulations in the biocontrol strain Pseudomonas fluorescens Pf29Arp.

    Science.gov (United States)

    Barret, M; Frey-Klett, P; Boutin, M; Guillerm-Erckelboudt, A-Y; Martin, F; Guillot, L; Sarniguet, A

    2009-01-01

    In soil, some antagonistic rhizobacteria contribute to reduce root diseases caused by phytopathogenic fungi. Direct modes of action of these bacteria have been largely explored; however, commensal interaction also takes place between these microorganisms and little is known about the influence of filamentous fungi on bacteria. An in vitro confrontation bioassay between the pathogenic fungus Gaeumannomyces graminis var. tritici (Ggt) and the biocontrol bacterial strain Pseudomonas fluorescens Pf29Arp was set up to analyse bacterial transcriptional changes induced by the fungal mycelium at three time-points of the interaction before cell contact and up until contact. For this, a Pf29Arp shotgun DNA microarray was constructed. Specifity of Ggt effect was assessed in comparison with one of two other filamentous fungi, Laccaria bicolor and Magnaporthe grisea. During a commensal interaction, Ggt increased the growth rate of Pf29Arp. Before contact, Ggt induced bacterial genes involved in mycelium colonization. At contact, genes encoding protein of stress response and a patatin-like protein were up-regulated. Among all the bacterial genes identified, xseB was specifically up-regulated at contact by Ggt but down-regulated by the other fungi. Data showed that the bacterium sensed the presence of the fungus early, but the main gene alteration occurred during bacterial-fungal cell contact. PMID:19121038

  11. Novel components of leaf bacterial communities of field-grown tomato plants and their potential for plant growth promotion and biocontrol of tomato diseases.

    Science.gov (United States)

    Romero, Fernando M; Marina, María; Pieckenstain, Fernando L

    2016-04-01

    This work aimed to characterize potentially endophytic culturable bacteria from leaves of cultivated tomato and analyze their potential for growth promotion and biocontrol of diseases caused by Botrytis cinerea and Pseudomonas syringae. Bacteria were obtained from inner tissues of surface-disinfected tomato leaves of field-grown plants. Analysis of 16S rRNA gene sequences identified bacterial isolates related to Exiguobacterium aurantiacum (isolates BT3 and MT8), Exiguobacterium spp. (isolate GT4), Staphylococcus xylosus (isolate BT5), Pantoea eucalypti (isolate NT6), Bacillus methylotrophicus (isolate MT3), Pseudomonas veronii (isolates BT4 and NT2), Pseudomonas rhodesiae (isolate BT2) and Pseudomonas cichorii (isolate NT3). After seed inoculation, BT2, BT4, MT3, MT8, NT2 and NT6 were re-isolated from leaf extracts. NT2, BT2, MT3 and NT6 inhibited growth of Botrytis cinerea and Pseudomonas syringae pv. tomato in vitro, produced antimicrobial compounds and reduced leaf damage caused by B. cinerea. Some of these isolates also promoted growth of tomato plants, produced siderophores, the auxin indole-3-acetic and solubilized inorganic phosphate. Thus, bacterial communities of leaves from field-grown tomato plants were found to harbor potentially endophytic culturable beneficial bacteria capable of antagonizing pathogenic microorganisms and promoting plant growth, which could be used as biological control agents and biofertilizers/biostimulators for promotion of tomato plant growth. PMID:26654914

  12. 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

  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. PMID:24499366

  14. 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. PMID:27067079

  15. 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)

    OpenAIRE

    Juliana Soler Arango; Luisa Fernanda Posada Uribe; Juan Carlos Pérez Naranjo

    2012-01-01

    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 ...

  16. Implementación de técnicas moleculares para la detección y cuantificación del agente de biocontrol Pantoea agglomerans CPA-2

    OpenAIRE

    Soto Muñoz, Lourdes

    2014-01-01

    Pantoea agglomerans CPA-2 es un agente de biocontrol (ACB) eficaz en el control de enfermedades de postcosecha en fruta de pepita y cítricos. No obstante, para implementar y registrar su uso como estrategia práctica de control en Europa es importante evaluar la capacidad del ACB para colonizar, persistir y propagarse en condiciones habituales de aplicación con un método de detección que permita diferenciar al antagonista del resto de la microbiota. La presente tesis doctoral tuvo como objetiv...

  17. 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.

  18. 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

  19. Mutation of rpiA in Enterobacter cloacae decreases seed and root colonization and biocontrol of damping-off caused by Pythium ultimum on cucumber.

    Science.gov (United States)

    Lohrke, Scott M; Dery, Pierre D; Li, Wei; Reedy, Ralph; Kobayashi, Donald Y; Roberts, Daniel R

    2002-08-01

    Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops. E. cloacae A145 is a mini-Tn5 Km transposon mutant of strain 501R3 that was significantly reduced in suppression of damping-off on cucumber caused by P. ultimum. Strain A145 was deficient in colonization of cucumber, sunflower, and wheat seeds and significantly reduced in colonization of corn and cowpea seeds relative to strain 501R3. Populations of strain A145 were also significantly lower than those of strain 501R3 at all sampling times in cucumber, wheat, and sunflower rhizosphere. Populations of strain A145 were not detectable in any rhizosphere after 42 days, while populations of strain 501R3 remained at substantial levels throughout all experiments. Molecular characterization of strain A145 indicated mini-Tn5 Km was inserted in a region of the E. cloacae genome with a high degree of DNA and amino acid sequence similarity to rpiA, which encodes ribose-5-phosphate isomerase. In Escherichia coli, RpiA catalyzes the interconversion of ribose-5-phosphate and ribulose-5-phosphate and is a key enzyme in the pentose phosphate pathway. Ribose-5-phosphate isomerase activity in cell lysates from strain A145 was approximately 3.5% of that from strain 501R3. In addition, strain A145 was a ribose auxotroph, as expected for an rpiA mutant. Introduction of a 1.0-kb DNA fragment containing only the rpiA homologue into strain A145 restored ribose phosphate isomerase activity, prototrophy, seedling colonization, and disease suppression to levels similar to those associated with strain 501R3. Experiments reported here indicate a key role for rpiA and possibly the pentose phosphate pathway in suppression of damping-off and colonization of subterranean portions of plants by E. cloacae. PMID:12182339

  20. 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.

  1. 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.

  2. Disruption of gene pqqA or pqqB reduces plant growth promotion activity and biocontrol of crown gall disease by Rahnella aquatilis HX2.

    Directory of Open Access Journals (Sweden)

    Lei Li

    Full Text Available Rahnella aquatilis strain HX2 has the ability to promote maize growth and suppress sunflower crown gall disease caused by Agrobacterium vitis, A. tumefaciens, and A. rhizogenes. Pyrroloquinoline quinone (PQQ, a cofactor of aldose and alcohol dehydrogenases, is required for the synthesis of an antibacterial substance, gluconic acid, by HX2. Mutants of HX2 unable to produce PQQ were obtained by in-frame deletion of either the pqqA or pqqB gene. In this study, we report the independent functions of pqqA and pqqB genes in relation to PQQ synthesis. Interestingly, both the pqqA and pqqB mutants of R. aquatilis eliminated the ability of strain HX2 to produce antibacterial substance, which in turn, reduced the effectiveness of the strain for biological control of sunflower crown gall disease. The mutation also resulted in decreased mineral phosphate solubilization by HX2, which reduced the efficacy of this strain as a biological fertilizer. These functions were restored by complementation with the wild-type pqq gene cluster. Additionally, the phenotypes of HX2 derivatives, including colony morphology, growth dynamic, and pH change of culture medium were impacted to different extents. Our findings suggested that pqqA and pqqB genes individually play important functions in PQQ biosynthesis and are required for antibacterial activity and phosphorous solubilization. These traits are essential for R. aquatilis efficacy as a biological control and plant growth promoting strain. This study enhances our fundamental understanding of the biosynthesis of an environmentally significant cofactor produced by a promising biocontrol and biological fertilizer strain.

  3. DNA-based methodologies for the quantification of live and dead cells in formulated biocontrol products based on Pantoea agglomerans CPA-2.

    Science.gov (United States)

    Soto-Muñoz, Lourdes; Torres, Rosario; Usall, Josep; Viñas, Inmaculada; Solsona, Cristina; Teixidó, Neus

    2015-10-01

    Pantoea agglomerans strain CPA-2 is an effective biocontrol agent (BCA) against the major postharvest pathogens present on pome and citrus fruits. Dehydration, such as freeze-drying, spray-drying and fluidized bed drying is one of the best ways to formulate BCAs. In this work, the survival of CPA-2 cells after formulation was determined by dilution plating and molecular methods as qPCR alone and combined with a sample pretreatment with a propidium monoazide dye (PMA-qPCR) and they were used to calculate treatment concentrations in efficacy trials on postharvest oranges. Furthermore, no significant differences in CPA-2 survival were observed as determined by dilution plating and PMA-qPCR after both the freeze drying and fluidized bed drying processes; however, an interesting significant difference was observed in the spray dried product comparing all quantitative methods. A difference of 0.48 and 2.17 log10 CFU or cells g/dw was observed among PMA-qPCR with qPCR and dilution plating, respectively. According to our study, dilution plating was shown to be an unreliable tool for monitoring the survival of CPA-2 after spray drying. In contrast, the combination of PMA and qPCR enabled a quick and unequivocal methodology to enumerate viable and VBNC CPA-2 cells under stress-dried conditions. Efficacy trials showed that, after 3 days, spray drying formulation rehydrated with 10% non-fat skimmed milk (NFSM) was as effective as fresh cells to control Penicillium digitatum in oranges. PMID:26114590

  4. Physiological mechanism governing slow and fast development in predatory ladybirds

    Czech Academy of Sciences Publication Activity Database

    Dixon, Anthony F. G.; Honěk, A.; Jarošík, Vojtěch

    2013-01-01

    Roč. 38, č. 1 (2013), s. 26-32. ISSN 0307-6962 R&D Projects: GA ČR GA206/09/0563; GA MŠk LC06073; GA MŠk ED1.1.00/02.0073 Institutional support: RVO:67179843 ; RVO:67985939 Keywords : Coccinellidae * food quality * geographical distribution Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (UEK-B) Impact factor: 1.434, year: 2013

  5. Invasive alien predator causes rapid declines of native European ladybirds

    Czech Academy of Sciences Publication Activity Database

    Roy, H. E.; Adriaens, T.; Isaac, N. J. B.; Kenis, M.; Onkelinx, T.; San Martin, G.; Brown, P. M. J.; Hautier, L.; Poland, R.; Roy, D. B.; Comont, R.; Eschen, R.; Frost, R.; Zindel, R.; Van Vlaenderen, J.; Nedvěd, Oldřich; Ravn, H. P.; Grégoire, J.-C.; de Biseau, J.-C.; Maes, D.

    2012-01-01

    Roč. 18, č. 7 (2012), s. 717-725. ISSN 1366-9516 Grant ostatní: MZe ČR(CZ) QH82047; Swiss Federal Office for the Environment(SE) F232-0377; project ALARM(BE) GOCE-CT-2003-506675 Institutional support: RVO:60077344 Keywords : biological control * biological invasions * citizen science Subject RIV: EH - Ecology, Behaviour Impact factor: 6.122, year: 2012 http://onlinelibrary.wiley.com/doi/10.1111/j.1472-4642.2012.00883.x/pdf

  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. PMID:26860841

  7. Biocontrol of Strawberry Anthracnose Caused by Colletotrichum fragariae%草莓炭疽病的生物防治研究

    Institute of Scientific and Technical Information of China (English)

    吉沐祥; 杨敬辉; 吴祥; 肖婷; 姚克兵; 庄义庆

    2013-01-01

    [目的]研究草莓炭疽病(Colletotrichum fragariae)的生物防治方法。[方法]采用菌丝生长抑制法测定枯草芽孢杆菌( Bacillus subtilis)(BS)和蛇床子素(SC)对草莓炭疽病菌的室内抑菌活性,并进行田间防治试验。[结果]室内测定结果表明,BS和 SC对草莓炭疽病菌菌丝生长都有极强的抑菌活性,其 EC50值分别为0.0075和1.0630 ml/L。田间防治结果显示,无论在避雨或露天条件下,BS(用量600~750 g/hm2)和25%咪鲜胺 EC (用量600 ml/hm2),在防治3次后7和14天的防治效果均达76%以上,但两药剂与SC(用量1800~2700 ml/hm2)的田间防治效果间有极显著差异(P<0.01)。[结论]枯草芽孢杆菌可以用于草莓炭疽病的防控。%[Objective] The aim was to explore biocontrol approaches of strawberry an-thracnose. [Method] With hyphal growth inhibition method, bacteriostatic activities of Bacil us subtilis and Osthole on strawberry anthracnose were measured and field test was carried out. [Result] The results show that both of Bacil us subtilis and Osthole were of higher bacteriostatic activity on strawberry anthracnose, and the values of EC50 were 0.007 5 mg/L and 1.063 0 ml/L, respectively. The result of field test show that the prevention effects of Bacil us subtilis (600-750 g/hm2) and 25% prochloraz (600 ml/hm2) both achieved higher than 76%, 7 and 14 d after triple medical applica-tions with rains sheltered or in open field. But the effects were of extremely signifi-cant differences with that of Osthole (1 800-2 700 ml/hm2) (P<0.01). [Conclusion] Bacil us subtilis can be made use of for control ing strawberry anthracnose.

  8. Auxin as a player in the biocontrol of Fusarium head blight disease of barley and its potential as a disease control agent

    Directory of Open Access Journals (Sweden)

    Petti Carloalberto

    2012-11-01

    Full Text Available Abstract Background Mechanisms involved in the biological control of plant diseases are varied and complex. Hormones, including the auxin indole acetic acid (IAA and abscisic acid (ABA, are essential regulators of a multitude of biological functions, including plant responses to biotic and abiotic stressors. This study set out to determine what hormones might play a role in Pseudomonas fluorescens –mediated control of Fusarium head blight (FHB disease of barley and to determine if biocontrol-associated hormones directly affect disease development. Results A previous study distinguished bacterium-responsive genes from bacterium-primed genes, distinguished by the fact that the latter are only up-regulated when both P. fluorescens and the pathogen Fusarium culmorum are present. In silico analysis of the promoter sequences available for a subset of the bacterium-primed genes identified several hormones, including IAA and ABA as potential regulators of transcription. Treatment with the bacterium or pathogen resulted in increased IAA and ABA levels in head tissue; both microbes had additive effects on the accumulation of IAA but not of ABA. The microbe-induced accumulation of ABA preceded that of IAA. Gene expression analysis showed that both hormones up-regulated the accumulation of bacterium-primed genes. But IAA, more than ABA up-regulated the transcription of the ABA biosynthesis gene NCED or the signalling gene Pi2, both of which were previously shown to be bacterium-responsive rather than primed. Application of IAA, but not of ABA reduced both disease severity and yield loss caused by F. culmorum, but neither hormone affect in vitro fungal growth. Conclusions Both IAA and ABA are involved in the P. fluorescens-mediated control of FHB disease of barley. Gene expression studies also support the hypothesis that IAA plays a role in the primed response to F. culmorum. This hypothesis was validated by the fact that pre-application of IAA reduced

  9. Gene expression analysis of the biocontrol fungus Trichoderma harzianum in the presence of tomato plants, chitin, or glucose using a high-density oligonucleotide microarray

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    Suárez M Belén

    2009-10-01

    Full Text Available Abstract Background It has recently been shown that the Trichoderma fungal species used for biocontrol of plant diseases are capable of interacting with plant roots directly, behaving as symbiotic microorganisms. With a view to providing further information at transcriptomic level about the early response of Trichoderma to a host plant, we developed a high-density oligonucleotide (HDO microarray encompassing 14,081 Expressed Sequence Tag (EST-based transcripts from eight Trichoderma spp. and 9,121 genome-derived transcripts of T. reesei, and we have used this microarray to examine the gene expression of T. harzianum either alone or in the presence of tomato plants, chitin, or glucose. Results Global microarray analysis revealed 1,617 probe sets showing differential expression in T. harzianum mycelia under at least one of the culture conditions tested as compared with one another. Hierarchical clustering and heat map representation showed that the expression patterns obtained in glucose medium clustered separately from the expression patterns observed in the presence of tomato plants and chitin. Annotations using the Blast2GO suite identified 85 of the 257 transcripts whose probe sets afforded up-regulated expression in response to tomato plants. Some of these transcripts were predicted to encode proteins related to Trichoderma-host (fungus or plant associations, such as Sm1/Elp1 protein, proteases P6281 and PRA1, enchochitinase CHIT42, or QID74 protein, although previously uncharacterized genes were also identified, including those responsible for the possible biosynthesis of nitric oxide, xenobiotic detoxification, mycelium development, or those related to the formation of infection structures in plant tissues. Conclusion The effectiveness of the Trichoderma HDO microarray to detect different gene responses under different growth conditions in the fungus T. harzianum strongly indicates that this tool should be useful for further assays that

  10. 不同来源丝核菌对马铃薯植株致病能力及生防效果研究%Pathogenic Ability and Biocontrol Effect of Different Pathogens to Potato Plants

    Institute of Scientific and Technical Information of China (English)

    肖翠红; 迟丽; 孙冬梅; 张丽梅

    2012-01-01

    [ Objective] Tlie aim was to study the pathogenic ability and biocontrol effect of different pathogens to potato plants. [ Method] The pathogenic ability of Rhizoctnnia solani soybean and Rhizoctonw solani rice to potato plants were studied by using living body vaccination bacteria method, and then the effects of biological control bacteria to disease were also investigated by spraying bio-control bacteria to disease. [Result] Rhizoctonia solani soybean had stronger pathogenic ability to potato plant than Rhizoctonia solani rice, among them the disease indexes of Rhizoc-tonia solani rice to leaf and stem of potato were only 25% and 50% , respectively. Bacteria had certain control effect to Rhizoctonia solani soybean, and the inhibitory rate reached 88%. Meanwhile the mixed bacteria and actinomycete had obvious bio-control effect to Rhizoctonia solani soybean, and the inhibitory rale reached 90%. [ Conclusion ] The research provides theoretical basis for the cultivation of potato and the control of Phyllachora graminis.%[目的]探讨不同来源丝核菌对马铃薯植株的致病能力及不同拮抗菌对病害的防治效果.[方法]采用活体接菌法研究了大豆根病病立枯丝核菌和水稻纹枯病立枯丝核菌对不同品种马铃薯植株的致病能力,并通过喷施生防菌研究了不同拮抗菌(细菌、放线菌和霉菌)对病害的防治效果.[结果]大豆根腐病立枯丝核菌对马铃薯植株的致病能力强于水稻纹枯病立枯丝核菌,其中水稻纹枯病立枯丝核菌对马铃薯叶的病指仅为25%,对茎的病指为50%.细菌对大豆根腐病立枯丝核菌具有一定的防治效果,抑菌率可达88%;细菌与放线菌的混合液对大豆根腐病立枯丝核菌的生防作用较明显,抑菌率达90%.[结论]为马铃薯栽培及黑痣病防治提供了理论依据.

  11. 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

  12. Optimization of culture conditions of the biocontrol strain CNY-04 against Botryis cinerea by response surface methodology%响应面法优化灰霉病生防菌CNY-04培养条件

    Institute of Scientific and Technical Information of China (English)

    陆继臣; 迟乃玉; 窦少华; 奥杰

    2013-01-01

    [Objective] In order to raising the antagonistic effect,the growth conditions of biocontrol strain CNY-04 was optimized.[Methods] The growth conditions of the biocontrol strain CNY-04 were optimized by response surface methodology basing on single factor tests.The growth curve was also measured.[Results] The optimal culture conditions of the biocontrol strain CNY-04 were determined for 0.5% glucose,2.0% peptone,0.1% yeast extract,0.5% beef extract,temperature at 32 ℃,pH 8.0,speeding at 150 r/min,the incubation time of 48 h,inoculation amount of 4%,liquid volume of 75 mL/250 mL.The OD600 of CNY-04 was 2.907 with the optimal growth conditions,consistenting with the predicted value.The antibacterial circle diameter was 44.5 mm,improving by 30.9%.[Conclusion] The optimal growth condition of the biocontrol strain CNY-04 was identified,providing a theoretical basis for enlargement of production.%[目的]通过优化生防菌CNY-04的培养条件,提高其对灰霉病菌的抑菌效果.[方法]在单因素试验的基础上,利用响应面法(Response surface methodology)对灰霉病生防菌CNY-04培养条件进行整体优化,并测其生长曲线.[结果]生防菌CNY-04最优培养条件为牛肉膏0.5%、蛋白胨2.0%、酵母膏0.1%、葡萄糖0.5%、时间48 h、接种量4%、温度32℃、pH 8.0、装液量75 mL/250 mL和转速150 r/min,在此培养条件下生防菌CNY-04的OD600为2.907,与模型预测值相符,对灰葡萄孢菌的抑菌圈直径为44.5 mm,较优化前提高了30.9%.[结论]从整体上确定了生防菌CNY-04的最优培养条件,为该菌扩大化生产提供理论基础.

  13. 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

  14. 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

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    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

  15. 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 106 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 introduces

  16. EVALUACIÓN DE MICROORGANISMOS AISLADOS DE GALLINAZA POR SU POTENCIAL PARA EL BIOCONTROL DE FUSARIUM (F. OXYSPORUM EN PLÁNTULAS DE UCHUVA (PHYSALIS PERUVIANA EVALUATION OF MICROORGANISMS INSOLATED FROM HEN MANURE FOR THEIR POTENCIAL AS BIOCONTROL AGENTS OF FUSARIUM (F. OXYSPORUM IN GOOSEBERRY (PHYSALIS PERUVIANA SEEDLINGS

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    Jorge Enrique Rodríguez Amézquita

    2010-12-01

    Full Text Available 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 gallinaza. Los aislamientos que mostraron antagonismo fueron posteriormente evaluados in vitro por su capacidad de restringir el crecimiento y esporulación de F. oxysporum. Cada uno de los aislamientos que mostró el mayor potencial antagónico fue inoculado simultáneamente con el patógeno en plántulas de uchuva y evaluado por sus efectos en contra de la incidencia de la enfermedad y la muerte de las plántulas. Los resultados indicaron que de los 39 microorganismos aislados de la gallinaza pura, 6 mostraron antagonismo contra F. oxysporum y entre ellos los más efectivos para restringir in vitro su crecimiento y esporulación fueron los hongos H2 y H6 y las bacterias B17 y B19. Las bacterias B17 y B19 resultaron ser las más efectivas en reducir no sólo la incidencia sino también la muerte de plántulas ocasionada por el patógeno. Según los resultados de la identificación, los hongos H2 y H6 pertenecen a los géneros Geotrichum sp. y Trichoderma sp, respectivamente y las bacterias B17 y B19 al género Bacillus.In Colombia, economic losses due to attack of Fusarium oxysporum in the gooseberry plantation are considerable. Fungi and bacteria isolated from 2 hen manure sources were evaluated for their potential as biological control agents of this pathogen. The evaluation was conducted in Petri dishes containing PDA by placing a 5 mm diameter disk, colonized by this pathogen, in the center of the plates and at 3 cm from the center, over the

  17. Anti-phytopathogen potential of endophytic actinobacteria isolated from tomato plants (Lycopersicon esculentum) in southern Brazil, and characterization of Streptomyces sp. R18(6), a potential biocontrol agent.

    Science.gov (United States)

    de Oliveira, Margaroni Fialho; da Silva, Mariana Germano; Van Der Sand, Sueli T

    2010-09-01

    Tomato plants (Lycopersicon esculentum) are highly susceptible to phytopathogen attack. The resulting intensive application of pesticides on tomato crops can affect the environment and health of humans and animals. The objective of this study was to select potential biocontrol agents among actinobacteria from tomato plants, in a search for alternative phytopathogen control. We evaluated 70 endophytic actinobacteria isolated from tomato plants in southern Brazil, testing their antimicrobial activity, siderophore production, indoleacetic acid production, and phosphate solubility. The actinomycete isolate with the highest antimicrobial potential was selected using the agar-well diffusion method, in order to optimize conditions for the production of compounds with antimicrobial activity. For this study, six growth media (starch casein-SC, ISP2, Bennett's, Sahin, Czapek-Dox, and TSB), three temperatures (25 degrees C, 30 degrees C, and 35 degrees C) and different pH were tested. Of the actinobacteria tested, 88.6% showed antimicrobial activity against at least one phytopathogen, 72.1% showed a positive reaction for indoleacetic acid production, 86.8% produced siderophores and 16.2% showed a positive reaction for phosphate solubility. Isolate R18(6) was selected due to its antagonistic activity against all phytopathogenic microorganisms tested in this study. The best conditions for production were observed in the SC medium, at 30 degrees C and pH 7.0. The isolate R18(6) showed close biochemical and genetic similarity to Streptomyces pluricolorescens. PMID:20542109

  18. Preliminary Study on Synergy Control Effect of Biocontrol Bacterium B579 and Carbendazim on Rhizoctonia solani%生防细菌B579与多菌灵协同防治立枯病的效果初探

    Institute of Scientific and Technical Information of China (English)

    杨秀荣; 孙淑琴; 田涛

    2011-01-01

    Carbendazim had strong inhibitory action to Rhizoctonia solani and had no effect on the growth of biocontrol bacterium B579 under 10 μg/tnl. The synergy effect of carbendazim and B579 on Rhizoctonia solani was studied in lab and by plot trial. The results showed that the mixture could effectively control Rhizoctonia solani and the control efficiency could reach to 87. 3% at 2 000 times of concentration.%多菌灵对立枯丝核菌(Rhizoctonia Solani)具有较强的抑制作用,且该药剂在10 μg/ml浓度下对生防细菌B579生长无影响.通过多菌灵与生防细菌B579协同作用的室内生测及室外盆栽试验,表明该混剂能够有效地防治蔬菜苗期立枯病,且在2000倍浓度下防效达87.3%.

  19. Biocontrole da mancha-aquosa do melão pelo tratamento de sementes com bactérias epifíticas e endofíticas Biocontrol of bacterial blotch of melon by seed treatment with epiphytic and endophytic bacteria

    Directory of Open Access Journals (Sweden)

    Aldenir de Oliveira

    2006-09-01

    avenae subsp. citrulli or treating healthy seeds in order to protect the plant challenged later with the pathogen. Melon seeds were microbiolized by immersion in suspensions (A570= 0,7, sown and evaluated for incubation period (PI, incidence (INC, disease severity (SEV and disease severity reduction (RSD. Only microbiolization of artificially infected seed using the endophytic ENM5 (not identified, ENM9 (Bacillus cereus, ENM13 (Bacillus sp., ENM16 (Bacillus cereus, ENM32 (Bacillus subtilis and ENM43 (Bacillus sp., showed potencial for disease control. After in vitro compatibility tests, these strains were reevaluated separately and in pairs, in relation to PI, INC, SEV, RSD, disease index (IDO and area under disease progress curve (AACPD. All treatments differed significantly (P= 0.05 from the control reaching 93.6% of RSD, with emphasis for ENM13 and ENM9 with 7.5 and 7.25 days of PI, 0.22 and 0.22 of SEV, 2.59 and 2.59 of IDO, and 0.22 and 0.39 of AACPD, respectively. In vitro tests to determine the putative mechanisms of action involved in biocontrol were performed. ENM13 and ENM9 solubilized phosphate, ENM5 presented antibiose against A. avenae subsp. citrulli, and ENM43 produced HCN while ENM16 and ENM32 did not show any of the tested mechanisms.

  20. Bioprospecting endophytic bacteria for biological control of coffee leaf rust Bioprospecção de bactérias endofíticas como agentes de biocontrole da ferrugem do cafeeiro

    Directory of Open Access Journals (Sweden)

    Humberto Franco Shiomi

    2006-02-01

    Full Text Available Suppression of plant diseases due to the action of endophytic microorganisms has been demonstrated in several pathosystems. Experiments under controlled conditions involving endophytic bacteria isolated from leaves and branches of Coffea arabica L and Coffea robusta L were conducted with the objective of evaluating the inhibition of germination of Hemileia vastatrix Berk. & Br., race II, urediniospores and the control of coffee leaf rust development in tests with leaf discs, detached leaves, and on potted seedling of cv. Mundo Novo. The endophytic bacterial isolates tested proved to be effective in inhibiting urediniospore germination and/or rust development, with values above 50%, although the results obtained in urediniospore germination tests were inferior to the treatment with fungicide propiconazole. Endophytic isolates TG4-Ia, TF2-IIc, TF9-Ia, TG11-IIa, and TF7-IIa, demonstrated better coffee leaf rust control in leaf discs, detached leaves, and coffee plant tests. The endophytic isolates TG4-Ia and TF9-Ia were identified as Bacillus lentimorbus Dutky and Bacillus cereus Frank. & Frank., respectively. Some endophytic bacterial isolates were effective in controlling the coffee leaf rust, although some increased the severity of the disease. Even though a relatively small number of endophytic bacteria were tested, promising results were obtained regarding the efficiency of coffee leaf rust biocontrol. These selected agents appears to be an alternative for future replacement of chemical fungicide.Supressão de doenças de plantas por microrganismos endofíticos tem sido demonstrada em diversos patossistemas. Neste trabalho foram selecionados isolados de bactérias endofíticas de folhas e ramos de cafeeiro com potencial para o controle biológico da ferrugem do cafeeiro, pois é conhecido que esses microrganismos podem possuir essa característica. Bactérias endofíticas isoladas previamente de folhas e ramos de Coffea arabica L e Coffea

  1. Identification of a novel small cysteine-rich protein in the fraction from the biocontrol Fusarium oxysporum strain CS-20 that mitigates Fusarium wilt symptoms and triggers defense responses in tomato

    Directory of Open Access Journals (Sweden)

    Larisa A. Shcherbakova

    2016-01-01

    Full Text Available The biocontrol effect of the nonpathogenic F. oxysporum strain CS-20 against the tomato wilt pathogen F. oxysporum f. sp. lycopersici (FOL has been previously reported to be primarily plant-mediated. This study shows that CS-20 produces proteins, which elicit defense responses in tomato plants. Three protein-containing fractions were isolated from CS-20 biomass using size exclusion chromatography. Exposure of seedling roots to one of these fractions prior to inoculation with pathogenic FOL strains significantly reduced wilt severity. This fraction initiated an ion exchange response in cultured tomato cells resulting in a reversible alteration of extracellular pH; increased tomato chitinase activity, and induced systemic resistance by enhancing PR-1 expression in tomato leaves. Two other protein fractions were inactive in seedling protection. The main polypeptide (designated CS20EP, which was specifically present in the defense-inducing fraction and was not detected in inactive protein fractions, was identified. The nucleotide sequence encoding this protein was determined, and its complete amino acid sequence was deduced from direct Edman degradation (25 N-terminal amino acid residues and DNA sequencing. The CS20EP was found to be a small basic cysteine-rich protein with a pI of 9.87 and 23.43% of hydrophobic amino acid residues. BLAST search in the NCBI database showed that the protein is new; however, it displays 48% sequence similarity with a hypothetical protein FGSG_10784 from F. graminearum strain PH-1. The contribution of CS20EP to elicitation of tomato defense responses resulting in wilt mitigating is discussed.

  2. Determination of the stereochemistry of the aggregation pheromone of harlequin bug, Murgantia histrionica

    Science.gov (United States)

    Preparation of a complete stereoisomeric library of 1,10-bisaboladien-3-ols and selected 10,11-epoxy-1-bisabolen-3-ols was earlier pivotal for the identification of the aggregation pheromone of the brown marmorated stink bug, Halyomorpha halys. Herein, we describe syntheses of remaining10,11-epoxy-1...

  3. Annular bone growth in phalanges of five Neotropical Harlequin Frogs (Anura: Bufonidae: Atelopus)

    OpenAIRE

    Erik Lindquist; Michael Redmer; Emily Brantner

    2012-01-01

    Skeletochronological studies were conducted on museum specimensrepresenting five species of the highly threatened Neotropical genus Atelopus (Bufonidae). We detected annular bone growth (expressed as lines of arrested growth [LAGs]) patterns in each species, and this might provide insight to understand demographic constituency infuture studies. In four of the five species under consideration, LAG counts in fore and hind limb bone occurred in a 1:1 ratio, indicating that bone growth was consis...

  4. Annular bone growth in phalanges of five Neotropical Harlequin Frogs (Anura: Bufonidae: Atelopus

    Directory of Open Access Journals (Sweden)

    Erik Lindquist

    2012-12-01

    Full Text Available Skeletochronological studies were conducted on museum specimensrepresenting five species of the highly threatened Neotropical genus Atelopus (Bufonidae. We detected annular bone growth (expressed as lines of arrested growth [LAGs] patterns in each species, and this might provide insight to understand demographic constituency infuture studies. In four of the five species under consideration, LAG counts in fore and hind limb bone occurred in a 1:1 ratio, indicating that bone growth was consistent within each individual. The use of skeletochronology in understanding historic and existing populations of Atelopus might assist in situ and ex situ population managers in making informed strategic conservation plans.

  5. Biomechanical and neurophysiological studies on audition in eared and earless harlequin frogs (Atelopus).

    Science.gov (United States)

    Lindquist, E D; Hetherington, T E; Volman, S F

    1998-08-01

    Tissue displacement of various body surfaces and the auditory midbrain sensitivities to sound were measured in Atelopus species with or without a tympanic middle ear ("eared" and "earless", respectively). Tissue displacement (vibration) of body regions was measured by laser Doppler vibrometer. The body wall directly overlying the lung is most dramatically displaced by sound pressure in all species tested. The otic (lateral head) region showed low displacement in earless species, but significant displacement to high-frequency sound in eared species. Peak tissue displacement of the body wall occurred within the frequency range of each species' advertisement vocalization. Peak tissue displacement of the otic region of the eared species also occurred within these frequencies. Multi-unit neurophysiological recordings of the auditory midbrain (torus semicircularis) also were obtained. Auditory sensitivity curves showed three distinct regions of sensitivity at low, middle, and high frequencies, the latter located within the frequency range of each species' advertisement vocalization. The correlation between auditory midbrain sensitivity and tissue displacement of the body wall region at advertisement vocalization frequencies, suggests that the body wall/lungs serve as the route of sound transfer to the inner ear in earless species and possibly in the eared species as well. PMID:9693994

  6. 保护地土壤生防木霉菌种群多样性研究%Study on Genetic Diversity of Biocontrol Trichoderma Population in Greenhouse Soils

    Institute of Scientific and Technical Information of China (English)

    贺字典; 高增贵; 高玉峰; 张洋

    2011-01-01

    采用传统的形态学特征和分子方法(ITS、TEF序列和UP-PCR)研究了蔬菜保护地土壤中木霉菌种群多样性及其影响因素.结果表明:提交genbank 11个木霉种的序列,分别为长枝木霉(Trichoderma longibrachiatum)、拟康氏木霉(Trichoderma pseudokoningii)、黄绿木霉(Trichoderma aureoviride)、棘孢木霉(Trichoderma asperellum)、深绿木霉(Trichoderma atroviride)、哈茨木霉(Trichoderma harzianum)、非钩木霉(Trichoderma inhamatum)、微孢木霉(Trichoderma minutisporum)、长孢木霉(Trichoderma longipile)和粘绿木霉(Trichoderma virens);木霉菌24个菌株经UP-PCR扩增,引物AS4、AS19、L45扩增出一条500 bp大小的木霉菌种的特征性谱带,其他谱带则为多态性谱带,多态性达93.5%;营养条件、杀菌剂及土壤因素对不同种木霉菌的影响不同,得到2株适应性较强的木霉菌株,有望成为生防菌株.%11 Trichoderma species were submitted to genbank by ITS ,TEF sequences analysis methods and effect factors of population diversity were studied in this paper, which included T. Longibrachiatum, T. Atroviride, T. Harziamun, T. Viren, T. Minutisporum, T. Pseudokoningii, T. Aureoviride, T. Inhamatum, T. Asperellum, T. Longipile and T. Helicum. At the same time, genetic diversity of Tnchoderma isolates were analyzed by Universally Primed PCR. A feature band ,500 bp, was the common one in 11 Trichoderma species,other bands were polymorphic,93.5 %. Futhermore, the effect of nutrition conditions, fungicides, soil factors etc. On Trichoderma was greatly different. 2 obtained strains which were strong adaptation, would be good bio-control strains.

  7. Identification and characterization of antagonistie strain biocontrol of cucumber Botrytis cinere and inhbition properties%黄瓜灰霉病拮抗菌的筛选鉴定及其抑菌特性研究

    Institute of Scientific and Technical Information of China (English)

    师宝忠; 仇艳肖; 马金亮; 周竞; 麻耀华

    2012-01-01

    从石家庄地区多个蔬菜大棚的根际土壤分离筛选到一株高效生防菌F1-2,对黄瓜灰霉病菌的抑菌圈直径高达33mm。根据菌株F1-2的形态特征、生理生化特性以及16SrDNA序列对其进行鉴定,初步确定为枯草芽孢杆菌(Bacillus subtilis)。采用生长速率法对拮抗菌的抑菌谱进行测定,其对所选的16种病原菌均有很好的抑制作用。实验还对拮抗菌F1-2的抑菌特性进行了研究,菌株连续传代至10代抑菌性能保持不变,菌株的发酵液对热和酸碱都比较稳定。该菌株的代谢产物具有广谱抑菌活性和较强的稳定性,具有开发成为灰霉病生防制剂的潜力。%An effective fungal strain F1--2 was isolated from rhizosphere soil of several greenhouses in Shiji- azhuang. The strain suppressed the growth of botrytis cinerea which was isolated from cucumber with the inhibition zone diameter of 33mm. The physiological and biochemical characteristics of the strain F1--2 and the identity of the 16SrDNA point out that this organism is Bacillus subtilis. Antimicrobial spectrum of the strain ,which could restrain the growth of 16 pathogens,was determined by growth rate method. The inhi- bition properties of strain F1--2 was researched in the experiment. After 10 generations,the antagonistic activity of the strain kept stable. Fermentation liquid of the strains have stability to heat, acid and base Metabolite of the strains was able to inhibit many kinds of pathogens and have high stability,which laid the foundation of development as botrytis cinerea suppressing Bio--control preparations.

  8. Selección de hongos antagonistas para el control biológico de Botrytis cinerea en viveros forestales en Chile Screening to antagonistic fungi for Botrytis cinerea biocontrol in Chilean forest nurseries

    Directory of Open Access Journals (Sweden)

    Gloria Molina Mercader

    2006-01-01

    this study was to select antagonistic fungi to B. cinerea, by means in vitro and nurseries assays, to determine its capacity as biocontrol agents of the «grey mould» disease in forest nurseries. The antagonistic potentials were obtained from the plants phyloplane, collected from forest nurseries. Seventy one fungi strains were evaluated in their capacity to reduce in vitro the pathogen colonization and sporulation by bioassays in Eucalyptus leaf discs. Selected strains were assayed under greenhouse conditions. Pinus radiata and E. globulus plants were sprayed with the pathogen (1x10(5 conidias/ml and later treated with the antagonists (1x 10(7 conidias/ml, evaluating the disease incidence and severity. In the in vitro assays, four strains of Trichoderma, three of Clonostachys, four of Penicillium, one of Cladosporium and other eight unidentified fungi strains did not significantly reduce pathogen colonization and sporulation. In the greenhouses assays, the strain Clonostachys (A-10 was able to reduce, in both P. radiata and E. globules, the disease incidence and severity. These results allow concluding that antagonists selected have the potential to B. cinerea control in forest nurseries.

  9. Screening,Identification and Biocontrol Potential of Antagonistic Fungi Against Strawberry Root Rot and Plant Growth Promotion%草莓根腐病拮抗真菌筛选鉴定及其防病促生作用

    Institute of Scientific and Technical Information of China (English)

    申光辉; 薛泉宏; 张晶; 段佳丽; 王东胜; 杨兴华

    2012-01-01

    [目的]探索利用植物病、健株根域土壤微生物区系比较法快速筛选高效、广谱且有实际防病促生作用生防真菌的可行性.[方法]根据菌落培养与扫描电镜形态特征及rDNA-ITS序列对拮抗真菌进行鉴定;生长速率法测定菌株无菌发酵滤液的拮抗活性,盖玻片对峙培养法观察拮抗真菌对草莓根腐病原菌菌丝形态的影响;室内发芽试验法测定真菌无菌发酵滤液促种子萌发活性;采用盆栽试验研究拮抗真菌对草莓根腐病的防病促生作用;土壤稀释平皿分离法测定拮抗真菌的定殖能力及对草莓根域微生物区系的影响.[结果]经鉴定,2株拮抗真菌HF3和HF7分别为灰黄青霉(Penicillium griseofulvum)和土曲霉(Aspergillus terreus),其无菌发酵滤液对7种供试病原真菌有较强的拮抗作用,培养96 h时,HF3对立枯丝核菌(Rhizoctonia solani)和大丽轮枝菌(Verticillium dahliae)菌丝生长抑菌率均为100.0%.HF3菌丝对大双孢柱孢(Cylindrocarpon macrodidyma CF9)菌丝具有溶解作用,使病菌菌丝出现扭曲、变细、断裂及原生质浓缩等畸变现象;HF3和HF7 103和104倍稀释无菌发酵滤液可促进甜瓜种子萌发及胚根、胚芽生长.HF7 104倍稀释液对西瓜种子萌发及胚芽、胚根生长具有促进作用;HF3和HF7对盆栽草莓根腐病的防效分别达53.0%和46.9%,同时可促进盆栽草莓植株生长,提高果实产量;菌株HF3和HF7在草莓根表定殖数量分别为2.23×105、1.02×105 CFU·g-1干土,同时减少了大双孢柱孢数量;接种HF3和HF7可有效调整草莓根域微生物区系,促进土壤微生态恢复平衡.[结论]通过植物病、健株根区土壤微生物区系比较可以快速筛选到高效广谱且有实际防病促生作用的生防真菌;HF3和HF7对草莓根腐病防治具有较高的潜在应用价值.%[Objective] The objective of this study is to verify the suitability of a rapid screening program for biocontrol

  10. Modelling Crop Biocontrol by Wanderer Spiders

    Science.gov (United States)

    Venturino, Ezio; Ghersi, Andrea

    2008-09-01

    We study mathematically the effects some spiders populations have on insects living in and near agroecosystems, where woods and vineyards alternate in the landscape as in the Alta Langa, Piemonte, NW Italy.

  11. Biocontrol of Aspergillus flavus by Pichia anomala

    Science.gov (United States)

    Aflatoxins are extremely potent natural carcinogens and a major food safety concern because of potential contamination of food commodities. Threshold levels set by the U. S. Food and Drug Administration for aflatoxins in foods for domestic consumption are less than 20 parts/ billion (ppb). However, ...

  12. Production Methods for Microbial Biocontrol Agents

    Science.gov (United States)

    A critical constraint to the commercial use of microbial biopesticides is the development of an economic production process. The production process must be cost-effective and yield a microbial propagule that is stable and efficacious under field conditions. Currently, the commercial production of ...

  13. Biocontrol: Fungal Parasites of Female Cyst Nematodes

    OpenAIRE

    Kerry, Brian

    1980-01-01

    Three species of fungi, Catenaria auxiliarls (Kühn) Tribe, Nematophthora gynophila Kerry and Crump, and a Lagenidiaceous fungus have been found attacking female cyst nematodes. All are zoosporic fungi which parasitize females on the root surface, cause the breakdown of the nematode cuticle, and prevent cyst formation. Their identification and some aspects of their biology are reviewed. N. gynophila is widespread in Britain and reduces populations of the cereal cyst nematode, Heterodera avenae...

  14. Development of novel Fungal Biocontrol Agents

    OpenAIRE

    Eiben, Ute; Lüth, Dr. Peter

    2006-01-01

    One of the tasks within the scope of REPCO is to select fungal isolates from a group of candidates highly hyperparasitc to Venturia inaequalis on apple.The selected isolates should be suitable for large-scale biotechnological production processes based on Solid-State fermentation. Therefore the ability to formulate a final product suitable for application and with good shelf-life and cost-competitiveness characteristics is also to be tested.

  15. Application of biocontrol agents in forest nurseries

    Science.gov (United States)

    Bare-root conifer seedling culture consists of growing seedlings (sown or transplanted) in soil, and is the predominant method for supplying America’s need for healthy regeneration stock to produce and sustain forests, wildlife food sources, fiber, wood products, paper, bio-pharmaceuticals and now p...

  16. FIRE ANT, BIOLOGY, ECOLOGY, AND BIOCONTROL

    Science.gov (United States)

    The red fire ant Solenopsis invicta was accidentally introduced into the United States from South America sometime in the 1930s. These ants do best in open, disturbed habitats associated with human activities. Fire ants construct large earthen mounds which function as solar collecting devises. Fire...

  17. Bacteriophage biocontrol in animals and meat products

    OpenAIRE

    Atterbury, R. J.

    2009-01-01

    Summary Since their discovery almost a century ago, bacterial viruses (bacteriophages or ‘phages’) have been used to prevent and treat a multitude of bacterial infections (phage therapy: PT). In addition, they have been the basis for many advances in genetics and biochemistry. Phage therapy was performed on human subjects in the United States, Europe and Asia in the few decades following their discovery. However, Western countries largely abandoned PT in favour of antibiotics in the 1940s. Th...

  18. Differences in the predatory behaviour of male and female ladybird beetles (Cocc inellidae)

    Czech Academy of Sciences Publication Activity Database

    Šipoš, Jan; Kvastegard, E.; Baffoe, K.O.; Sharmin, K.; Glinwood, R.; Kindlmann, Pavel

    2012-01-01

    Roč. 2, č. 1 (2012), s. 45-49. ISSN 1805-0174 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Coccinella septempunctata * functional response * foraging * aphids Subject RIV: EH - Ecology, Behaviour

  19. Bt-genetically engineered potatoes preserve aphidophagous ladybird beetles (Coleoptera: Coccinellidae)

    Czech Academy of Sciences Publication Activity Database

    Kalushkov, P.; Nedvěd, Oldřich

    Ponta Delgada : Biology Department University of tahe Azores, 2002. s. 43. [International Symposium on Ecology of Aphidophaga /8./. 01.09.2002-06.09.2002, Ponta Delgada] Institutional research plan: CEZ:AV0Z5007907 Keywords : GMO * non-terget organism * insecticides Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection

  20. Preference among threee aphid species by the predatory ladybird beetle Harmonia axyridis in the laboratory

    Czech Academy of Sciences Publication Activity Database

    Šenkeříková, P.; Nedvěd, Oldřich

    Vol. 94. Darmstadt: Federal Research Centre for Cultivated Plants, 2013 - (Sloggett, J.; Brown, P.; Roy, H.), s. 123-130 ISBN 978-92-9067-273-9. [Working Group „Benefits and Risks of Exotic Biological Control Agents“. Proceedings of the Second Meeting at Hluboká. Hluboká nad Vltavou (CZ), 30.09.2011-03.11.2011] Grant ostatní: MZe ČR(CZ) QH82047 Institutional support: RVO:60077344 Keywords : Aphis philadelphi * optimal foraging * Philadelphus Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection

  1. Status of insecticide resistance and selection for imidacloprid resistance in the ladybird beetle Propylaea japonica (Thunberg).

    Science.gov (United States)

    Tang, Liang-De; Qiu, Bao-Li; Cuthbertson, Andrew G S; Ren, Shun-Xiang

    2015-09-01

    Field populations or strains of Propylaea japonica collected from four places in southern China (Guangzhou, Nanning, Guilin, and Yuxi) were tested for susceptibility to four insecticides (abamectin, imidacloprid, beta-cypermethrin, and chlorpyrifos) by the Petri-dish Potter tower method and compared with an insecticide-susceptible strain. Concentrations that proved lethal for 50% of the tested individuals (LC50) were estimated by probit analysis, and resistance factors (RF) were calculated at the LC50 level, which ranged from 1.6 to 10.1, depending on the insecticide. In addition, the Guangzhou strain formed the original population for imidacloprid resistance selection. After selection for 20 generations, the resistance had increased 39.3-fold. Fitness analysis in terms of such traits as fecundity, days to maturity, and survival showed that although both resistant and susceptible populations developed at comparable rates, the resistant strain was less fecund (it laid fewer eggs and a smaller proportion of those eggs hatched and resulted in adults), attaining a fitness score of only 0.56 relative to the susceptible strain. These observations suggest that it is possible to detect strains of P. japonica highly resistant to insecticides under laboratory conditions, and that resistance to imidacloprid carries considerable fitness costs to P. japonica. The study served to expand our understanding of the impact of imidacloprid resistance on biological parameters of P. japonica in more detail and to facilitate the deployment of natural enemies resistant to insecticides in integrated pest management. PMID:26267056

  2. A Ladybird Grows Wing%长翅膀的瓢虫

    Institute of Scientific and Technical Information of China (English)

    David C. Card

    2006-01-01

    @@ A caramel1 sun melts through the sea sky, as Tommy rides his tricycle across the back garden path. He stops when he reaches the picket2 fence, dropping a foot on the lush green grass,using it as a post to shift his body full circle,until he faces his mother,who is sunbathing by the porch. He continues this sequence until his legs feel heavy,like two stone pillars,which urges him to dismount his tricycle and focus his attention to the sandbox, to the flower garden,to the water well.

  3. Barcode haplotype variation in North American agroecosystem ladybird beetles (Coleoptera: Coccinellidae

    Science.gov (United States)

    DNA barcodes have proven invaluable in identifying and distinguishing insect pests, for example for determining the provenance of exotic invasives, but relatively few insect natural enemies have been barcoded. We used Folmer et al.’s universal invertebrate primers (1994), and those designed by Heber...

  4. Living with the enemy: parasites and pathogens of the invasive alien ladybird Harmonia axyridis

    Science.gov (United States)

    Harmonia axyridis is an invasive alien predator in many countries across the world. The rapid establishment and spread of this species is of concern because of the threat it poses to biodiversity as a generalist predator. Understanding the mechanisms that contribute to the success of this species ...

  5. Suitability of gramineous plants as food for the phytophagous ladybird Cynegetis impunctata L. (Coleoptera: Coccinellidae)

    Czech Academy of Sciences Publication Activity Database

    Kalushkov, P.; Chehlarov, E.; Nedvěd, Oldřich

    2013-01-01

    Roč. 65, č. 4 (2013), s. 561-564. ISSN 0324-0770 Grant ostatní: GA JU(CZ) 144/2010/100 Institutional support: RVO:60077344 Keywords : grass * development time * body mass Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 0.357, year: 2013 http://www.acta- zoologica -bulgarica.eu/downloads/acta- zoologica -bulgarica/2013/65-4-561-564.pdf

  6. Chilocorus renipustulatus (Coleoptera: Coccinellidae) dominates predatory ladybird assemblages on Sorbus aucuparia (Rosales: Rosaceae)

    Czech Academy of Sciences Publication Activity Database

    Kula, E.; Nedvěd, Oldřich

    2011-01-01

    Roč. 108, č. 4 (2011), s. 603-608. ISSN 1210-5759 Grant ostatní: Ministry of Education of the Czech Republic(CZ) VZ MSM 6215648902; Ministry of Agriculture(CZ) QH82047 Institutional research plan: CEZ:AV0Z50070508 Keywords : Coccinellidae * Chilocorus renipustulatus * scale insect Subject RIV: EH - Ecology, Behaviour Impact factor: 1.061, year: 2011 http://www.eje.cz/scripts/viewabstract.php?abstract=1659

  7. Living with the enemy: parasites and pathogens of the ladybird Harmonia axyridis

    DEFF Research Database (Denmark)

    Roy, Helen E.; Rhule, Emma; Harding, Susanne;

    2011-01-01

    Harmonia axyridis is an invasive alien predator in many countries across the world. The rapid establishment and spread of this species is of concern because of the threat it poses to biodiversity as a generalist predator. Understanding the mechanisms that contribute to the success of this species...

  8. Are thermal constants constant? A test using two species of ladybird

    Czech Academy of Sciences Publication Activity Database

    Jarošík, Vojtěch; Kumar, G.; Omkar, Dr.; Dixon, Anthony F. G.

    2014-01-01

    Roč. 40, Feb 2014 (2014), s. 1-8. ISSN 0306-4565 R&D Projects: GA ČR GA206/09/0563; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67985939 ; RVO:67179843 Keywords : lower developmental threshold * degree days * food quality Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (UEK-B) Impact factor: 1.505, year: 2014

  9. 近10年来我国草原虫害生物防控综合配套技术的研究与推广进展%Integrated biocontrol of insect pests during the last 10 years in China:Research and practice

    Institute of Scientific and Technical Information of China (English)

    洪军; 杜桂林; 旭疆; 何新天; 张焕强; 林峻

    2014-01-01

    草原虫害防治是农业部较早大规模组织开展的防灾减灾工作之一。在长期的实践工作中,草原虫害防治始终坚持“预防为主,综合防治”的植保方针,逐步建立了“以生物防治为主,化学防治为辅”的技术路线。2002年起,全国畜牧总站在全国牧区组织开展了《草原虫害生物防控综合配套技术推广应用》项目。该项目的实施带动了全国的草原害虫防治,为草原可持续发展提供了技术支撑。本文以该项目的进展为基础,简要总结介绍了草原害虫防治的实施背景、开展情况及建设成果,包括以生态系统平衡原理为指导,对虫害监测预警、生物防控和施药技术等进行集成创新与组装配套,使草原害虫密度长期控制在经济阈值以下,实现草原生态系统平衡等。%Control of Grassland insect pests is an example of important early disaster prevention and mitigation work by the Ministry of Agriculture,China.The grassland insect pest control policy was based on prevention first followed by integrated control.The long-term practice was to use biocontrol as the primary means of con-trol with chemical control used in a complimentary role.The establishment of biocontrol techniques for insect pests has been undertaken by the China Animal Industry Station since 2002 .Ecosystem balance was used as the main driver of policy in the program.Insect pest monitoring and early warning,biocontrol and pesticide appli-cation technology was utilized,and insect pest density maintained below the economic threshold level during this time.The achievements of the program have been recognized in the National Agricultural Harvest A-wards.The background,progress and major achievements of the program are introduced with the aim of infor-ming people about the current status of grassland insect pest control in China.

  10. Synthèse bibliographique : l'écologie chimique des coccinelles

    Directory of Open Access Journals (Sweden)

    Durieux, D.

    2010-01-01

    Full Text Available Review: chemical ecology of ladybird beetles. This paper reviews the chemical ecology of ladybird beetles (Coleoptera: Coccinellidae to present the role of semiochemicals involved in plant-ladybird, prey-ladybird and predator-ladybird interactions. Ladybird beetles use these compounds to locate their prey, mate, protect themselves from predation or cannibalism, find a shelter to overwinter or ensure a better survival for their offspring. Thorough studies on ladybird behaviors towards these compounds could lead to their practical implementation in integrated strategies using ladybirds to control pests, like aphids or mealybugs.

  11. 75 FR 21568 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition to List the Harlequin...

    Science.gov (United States)

    2010-04-26

    ... and size. This butterfly is brownish black at the dorsal area with deep orange markings and confused... references cited is available on the Internet at http://www.regulations.govand upon request from...

  12. Variabilidade genética na região its do rDNA de isolados de trichoderma spp. (Biocontrolador e Fusarium oxysporum f. sp. Chrysanthemi Genetic variability in rDNA ITS region of Trichoderma spp. (biocontrole agent and Fusarium oxysporum f. sp. chrysanthemi isolates

    Directory of Open Access Journals (Sweden)

    Josiane Pacheco Menezes

    2010-02-01

    Full Text Available A análise de características morfológicas e culturais podem não ser suficientes para uma caracterização precisa das espécies de Trichoderma e Fusarium. Objetivou-se, neste trabalho, caracterizar a região do Espaço Interno Transcrito (ITS do rDNA dos isolados UFSMT15.1, UFSMT16 e UFSMT17 de Trichoderma spp. utilizados no biocontrole de Fusarium oxysporum f. sp. chrysanthemi (isolado UFSMF6. A extração de DNA de cada isolado foi realizada a partir de micélio produzido em meio líquido Batata-Dextrose. As amostras de DNA genômico foram submetidas à Reação em Cadeia da Polimerase (PCR com os oligonucleotídeos iniciadores universais ITS1 e ITS4 e o produto gerado foi sequenciado. Os fragmentos gerados pela amplificação da PCR foram tratados com as enzimas de restrição HaeIII, HinfI e MboI. As regiões ITS1, ITS2 e 5.8S do rDNA desses isolados fúngicos foram amplificadas com sucesso. A região ITS dos isolados UFSMT15.1, UFSMT16 e UFSMT17 de Trichoderma e o isolado UFSMF6 de Fusarium apresentaram uma banda simples com um fragmento de aproximadamente 600 pares de base (pb. As enzimas de restrição HaeIII, HinfI e MboI geraram polimorfismo de bandas entre os isolados. Com base nas análises da sequência de DNA, os isolados UFSMT15.1, UFSMT16, UFSMT17 e UFSMF6 apresentaram maior similaridade com as espécies Trichoderma koningiopsis, Hypocrea virens, Hypocrea lixii e Fusarium oxysporum, respectivamente.The analysis of morphological and cultural characteristics may not enough for the characterization of the species of Trichoderma and Fusarium. The aim of this work was to characterize the Internal Transcribed Spacer (ITS region of the rDNA of UFSMT15.1, UFSMT16 and UFSMT17 isolates of Trichoderma spp. used in the biocontrol of Fusarium oxysporum f. sp. chrysanthemi UFSMF6. DNA extraction of each isolate was accomplished starting from hyphae produced in liquid medium Potato-Dextrose-Agar. The samples of genomic DNA were submitted to

  13. Genetic Modification of a Biocontrol Agent Pseudomonas fluorescens 2P24 by a Harpin Coding Gene%利用编码harpin蛋白的基因遗传改良生防荧光假单胞菌2P24

    Institute of Scientific and Technical Information of China (English)

    赵倩; 邹丽芳; 邹华松; 李玉蓉; 陈功友

    2012-01-01

    Biocontrol agent Pseudomonas fluorescens 2P24,one of plant growth-promoting rhizobacteria(PGPR),possesses a type-Ⅲ secretion system(T3SS) for association with plants.To enable 2P24 to express a harpin protein which triggers hypersensitive response(HR) in plants and to have the ability to induce resistance to plant pathogen infection,we constructed a fusion of a hap1 gene,which encodes a harpin of Xanthomonas oryzae pv.oryzicola,with a promoter of avrPto1 of Pseudomonas syringae pv.tomato DC3000 which was induced in 2P24.This recombination led 2P24 to express the harpin protein Hpa1.The protein,secreted via the T3SS of 2P24,triggered HR in tobacco via the activation of HR marker genes,HIN1 and HRS203J,and pathogenesis-related protein gene PR1a.The genetic modified 2P24 with the harpin coding gene,as the recipient strain 2P24,had antimicrobial ability against wheat scab Fusarium graminearum and cotton wilt F.oxysporum f.sp.vasinfectum.Using HR-elicitors from plant-pathogen interactions to genetically modify biocontrol antimicrobes provides a fundamental basis for plant disease control.%荧光假单胞菌Pseudomonas fluorescens 2P24是根围促生细菌(PGPR),具有Ⅲ型分泌系统(T3SS)。为了在2P24中表达植物过敏反应激发子harpin,赋予生防菌诱导抗病性能力,本文选择可在2P24中表达的来自Pseudomonas syringae pv.tomato DC3000的avrPto1基因启动子与水稻细菌性条斑病菌Xanthomonasoryzae pv.oryzicola harpin蛋白编码基因hpa1进行融合,实现了harpin蛋白在2P24的表达。重组菌株通过T3SS分泌harpin蛋白,可激发烟草产生过敏反应(HR),激活HR途径的HIN1基因和HRS203J基因以及病程相关蛋白PR1a基因的转录表达。harpin重组菌株与2P24一样,对小麦赤霉病菌Fusarium graminearum和棉花枯萎病菌F.oxysporum f.sp.vasinfectum具有抑制作用。这为利用植物-病原物互作中激发植物产生抗病性的激发子来遗传改良生防微生物奠定了理论和实践基础。

  14. 放线菌剂与腐植酸钾对魔芋抗病促生效果研究%Study of Combined Application of Actinomycetes Biocontrol Agents and Potassium Humate on Disease Resistance and Growth-promoting Effect of Amorphophallus Konjac

    Institute of Scientific and Technical Information of China (English)

    张忠良; 刘列平; 何斐

    2014-01-01

    分别以不施菌剂、不施腐植酸钾为对照,采用小区试验,探讨生防放线菌剂与腐植酸钾配施条件下二者对魔芋的防病促生作用。试验结果表明:(1)​当腐植酸钾与3号放线菌配施时,具有较强的防病促生作用。30克/株、60克/株、90克/株腐植酸钾分别配施3号菌剂时,与不施腐植酸钾对照相比,魔芋病害相对防效、增产率及增长系数分别提高了9.8%~41.6%、17.1%~76.3%和20.1%~64.2%。其中,60克/株腐植酸钾配施3号菌剂时效果最明显。(2)​当放线菌剂与腐植酸钾配施时,具有较强的防病促生作用。1、2、3号放线菌剂与60克/株腐植酸钾配施,与不施菌剂对照相比,魔芋病害相对防效、增产率及增长系数分别提高了11.7%~89.7%、33.3%~150.9%和38.5%~175.0%。其中2、3号放线菌剂与60克/株腐植酸钾配施处理效果较好。研究表明,腐植酸钾与放线菌剂配施能促进魔芋生长,提高魔芋产量,降低发病率。%With no actinomycetes and potassium humate treatments as control(CK), the effect of actinomycetes and potassium humate on disease resistance and growth-promoting of Amorphophallus konjac in the plot trials were evalu-ated. Results showed that:(1) Combined application of potassium humate and actinomycetes No.3 had strong disease resistance and growth-promoting effect. Under 30, 60, 90 gram per plant of potassium humate combined with actinomy-cetes No.3 treatment, biocontrol effect increased by 9.8%~41.6%, yield increased by 17.1%~76.3%and growth factor increased by 20.1%~64.2% compared with the group without potassium humate. Among which, the combined ap-plication of 60 gram per plant of potassium humate and actinomycetes No.3 had the most obvious effect. (2) Combined application of actinomycetes and potassium humate had signiifcant anti-disease and growth-promoting effect. Three kind of actinomycetes combined with 60 gram per plant of potassium

  15. Study on Imporved Biocontrol of Pichia membranifaciens for Control of Green Mold Decay on Chinese Bayberry Fruit by Methyl Jasmonate%茉莉酸甲酯提高膜醭毕赤酵母对杨梅果实采后绿霉病生防效力的研究

    Institute of Scientific and Technical Information of China (English)

    汪开拓; 郑永华; 尚海涛; 金鹏; 芮怀瑾

    2011-01-01

    研究了茉莉酸甲酯(Methyl jasmonate,MeJA)复合膜醭毕赤酵母(Pichia membranaefaciens)处理对“乌种”杨梅果实由桔青霉(Penicillium citrinum)引起的绿霉病的抑制效果,同时分析了MeJA对酵母菌和病原菌生长以及果实抗病性的影响。结果显示:MeJA可有效提升P.membranefacien生防效力,10μmol/L MeJA与1×10^9CFU/mLP.membranefacien菌悬液的复合处理比单一处理能更有效抑制杨梅果实绿霉病的发生;该复合处理也更为显著的诱导了杨梅果实抗病相关酶活性的上升;此外,MeJA还可直接提高P.membranaefaciens在NYDB培养基和杨梅果实伤口处的数量,但MeJA对病原菌P.citrinum生长无抑制效果。这些结果表明,MeJA主要是通过直接促进拮抗酵母生长以及间接诱导果实抗病性来提升P.membranaefaciens生防效力,从而起到有效抑制杨梅果实采后腐烂的作用。%The present study was to investigate the effect of the combined treatment of MeJA and antagonistie yeast Pichia membranifaciens for control of green mold decay caused by Penicillium citrinum on Chinese bayberry fruit ( Myrica rubra Seib & Zucc. Cv Wumei) and to analyze the effect of MeJA on the growth of the yeast and pathogen as well as the disease resistance. The results exhibited that the biocontrol activity of P. membranifacierts on the disease was enhanced by the addition of MeJA, 1 × 10^9 CFU/mL P. membranifaciens combined with 10 μmol/L MeJA resulted in a remarkably improved control of the disease compared with applying yeast or MeJA alone. Meanwhile, the combined treatment induced higher defense-related enzymes activities than either alone. In addition, adding MeJA positively influenced the population of P. membranifaciens in NYDB medium and fruit wounds. However, MeJA had no direct inhibitory effect on spore germination and germ tube elongation of P. citrinum. Thus, these results suggested that MeJA could

  16. 贵州省黔东南州太子参立枯病的病害分析及生防初探%Study on Pathogen and Bio-control of Damping-off Disease in Pseudostellaria heterophylla in Qiandongnan Prefecture of Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    张国辉; 王龙; 任永权; 贺定翔; 兰才武; 范成明; 陈宇红; 胡赞民

    2015-01-01

    Fungal diseases occur seriously in Pseudostel aria heterophyl a in Qian-dongnan Prefecture of Guizhou Province from March to May every year. By field in-vestigation, tissue isolation and microscopic identification, the main pathogen was iden-tified as Rhizoctonia solani, the pathogen of damping-off disease. At the same time, Alternaria alternate was also isolated from the sampled diseased soil, and it has pathogenicity to Pseudostel aria heterophyl a seedlings. The bio-control test showed that GH18 strain (Bacil us spp.) had significant inhibitory effects on Rhizoctonia solani and Alternaria alternate.%贵州省黔东南州太子参( Radix pseudostellariae)在每年3~5月份都会发生严重真菌病害,经实地调查、组织分离和显微鉴定,得到主要致病菌为立枯丝核菌(Rhizoctonia solani),其导致的病害为太子参立枯病。同时,还在病土中分离纯化得到对太子参种苗有致病能力的病原菌互隔文链孢霉(Alternariaalternate)。生防试验结果表明,芽孢杆菌(Bacillus spp.)GH18菌株对病原菌立枯丝核菌(Rhizoctoniasolani)和病原菌互隔文链孢霉(Alternaria alternate)的抑菌效果显著。

  17. The Characteristics and Bio-control Technology of Odor Pollution at Municipal Solid Waste (MSW) Landfill Sites%城市生活垃圾填埋场恶臭污染特征和生物控制技术研究进展

    Institute of Scientific and Technical Information of China (English)

    李玲; 熊骏生; 陶凌燕; 叶灵波; 秦雪艳; 徐梦婷; 丁颖

    2014-01-01

    Along with rapid development of Chinese cities ,the production of MSW is increasing daily .Sanitary landfill is currently the main mean of the treatment and disposal of municipal solid waste . However ,landfill odor nuisances occur frequently ,which seriously affect the work ,life and health of the residents in surrounding areas .Therefore ,studying the odor pollution prevention and control techniques ,understanding the major odor sources of the landfill ,odor components as well as its temporal and spatial distribution characteristics ,grasping the research progress of bio-control technology of odor , are of important practical significances .%随着中国城市经济的迅猛发展,城市垃圾的产量也与日俱增。卫生填埋是目前处理处置城市生活垃圾的主要方式,但垃圾填埋场恶臭扰民事件频发,其恶臭污染问题已经严重影响到周边区域居民的工作、生活和健康。因此,开展垃圾填埋场恶臭污染特征和防控技术研究,了解垃圾填埋场的主要恶臭发生源、恶臭气体主要成分及其时空分布特征,掌握垃圾填埋场恶臭生物控制技术的最新研究进展,具有重要的现实意义。

  18. Effect assessment of Puccinia xanthii f sp ambrosiae-trifidae as a biocontrol agent to control giant ragweed%苍耳柄锈菌三裂叶豚草专化型对三裂叶豚草控制效果评价

    Institute of Scientific and Technical Information of China (English)

    丁建云; 姚丹丹; 陈继东; 崔建臣; 胡冬雪; 张小利

    2014-01-01

    Based on data from systematic investigation of giant ragweed inoculated with Puccinia xanthii f. sp. ambrosiae-trifidae in field in Huairou area in 2011-2013, the occurrence regularity and biocontrol effect of giant ragweed rust were evaluated. The results indicated that giant ragweed rust was natural epidemic in Baoshan Temple area in Huairou. Giant ragweed rust occurred in early June. All the giant ragweed plants were almost infected in the middle of July and some infected plants were died. P.xanthii f. sp. ambrosiae-trifidae exhibits good control effect on growth, seed amount and seed weight of giant ragweed. The death rate of the infected giant ragweed plants was nearly 30% in the end of September and the death plants had no seed.%2011~2013年在北京怀柔宝山寺地区通过野外接菌后定点定株系统调查,探索三裂叶豚草锈病的流行规律,评价苍耳柄锈菌三裂叶豚草专化型对三裂叶豚草的控制效果。结果表明:苍耳柄锈菌三裂叶豚草专化型在北京怀柔宝山寺地区能完成周年侵染循环:6月初三裂叶豚草开始有感染锈病症状,7月中、下旬几乎全部三裂叶豚草植株感病,且开始有整株死亡。苍耳柄锈菌三裂叶豚草专化型对三裂叶豚草有较好的控制效果:该菌抑制三裂叶豚草植株生长,减少种子数量,减轻种子重量,9月末30%左右的感病三裂叶豚草植株死亡,死亡植株不能产生种子。

  19. Redescription of the Hispaniolan ladybird genus Bura Mulsant (Coleoptera: Coccinellidae) and justification for its transfer from Coccidulinae to Sticholotidinae

    Science.gov (United States)

    In the current work, we discuss the features of Bura (Coleoptera: Coccinellidae) that justify its transfer from Coccidulinae to Sticholotidinae, speculate on circumstances that led to its prior misclassification, and highlight current problems in the delineation of the afforementioned lady beetle su...

  20. The effects of thirteen species of aphids on some life history parameters of the ladybird Coccinella septempunctata

    Czech Academy of Sciences Publication Activity Database

    Kalushkov, P.; Hodek, Ivo

    2004-01-01

    Roč. 49, - (2004), s. 21-32. ISSN 1386-6141 R&D Projects: GA AV ČR IBS5007102 Institutional research plan: CEZ:AV0Z5007907 Keywords : adult fresh weight * essential food * fecundity Subject RIV: EG - Zoology Impact factor: 0.790, year: 2004