The invention relates to control of fungal foliar diseases in plants, preferaby Rosaceae, such as apple scab (Venturia inaequalis), pear scab (Venturia pirina), brown spot (Stemphylium vesicarium) and powdery mildew (Podosphaera leucotricha) by treatment of plant with an extract of Yucca species...
Färber, Ruth B Küng; Chin, Khoon Min; Leadbitter, Neil
The sensitivity of Venturia inaequalis to trifloxystrobin was monitored by both in vitro (spore germination) and in vivo tests (on apple seedlings). There was good correlation between the in vitro and in vivo results. Baseline sensitivity was established with 95 bulk isolates from Europe between 1995 and 1998 which showed a narrow sensitivity range-factor of up to 17 between the least and most sensitive isolates. Monitoring of populations originating from trifloxystrobin-treated and untreated orchards between 1995 and 1999 showed only sensitive isolates and no performance deficiencies were reported. Data also show that trifloxystrobin is not cross-resistant to anilinopyrimidines and triazoles, but is cross-resistant to kresoxim-methyl, another strobilurin which also inhibits the cytochrome bc1 enzyme complex at the Qo-site in the respiration chain of fungal mitochondria (QoI inhibitors). Under experimental conditions from a specific trial site in Switzerland, where trifloxystrobin has been tested since 1994, isolates containing conidia resistant to Qo inhibitors were detected in 1997 and 1999. However no obvious performance deficiencies were reported. Nevertheless these results demonstrate a risk for the development of practical resistance in V inaequalis to Qo inhibitors and therefore a need to apply resistance management principles strictly.
Speksnijder, A.G.C.L.; Lombaers-van der Plas, C.H.; Köhl, J.
Venturia inaequalis causes apple scab. The control of the disease in organic apple production depends on the use of copper which will be restricted in future for environmental reasons. In the search for environmental friendly microbial biocontrol agents and stimulation of antagonistic populations in
Turan, Ceren; Nanni, Irene Maja; Brunelli, Agostino; Collina, Marina
The objective of this study was to develop a rapid method to isolate DNA from Venturia inaequalis spores for use in diagnostic DNA mutation analysis. Chelex-100 resin was evaluated and compared with a well established DNA exctraction method, utilizing CTAB in order to have a robust comparison. In this research we demonstrated that Chelex-100 efficiently makes extraction of the DNA from V. inaequalis spores available for direct use in molecular analyses. Also, the quantity and quality of extracted DNA were shown to be adequate for PCR analysis. Comparatively, the quality of DNA samples isolated using Chelex method was better than those extracted using CTAB. In conclusion, the Chelex method is recommended for PCR experiments considering its simplicity and cost-effectiveness. Copyright © 2015. Published by Elsevier B.V.
Full Text Available Venturia inaequalis and V. pirina are Dothideomycete fungi that cause apple scab and pear scab disease respectively. Whole genome sequencing of V. inaequalis and V. pirina isolates has revealed predicted proteins with sequence similarity to AvrLm6, a Leptosphaeria maculans effector that triggers a resistance response in Brassica napus and Brassica juncea carrying the resistance gene, Rlm6. AvrLm6-like genes are present as large families (> 16 members in all sequenced strains of V. inaequalis and V. pirina, while in L. maculans, only AvrLm6 and a single paralogue have been identified. The Venturia AvrLm6-like genes are located in gene poor regions of the genomes, and mostly in close proximity to transposable elements which may explain the expansion of these gene families. An AvrLm6-like gene from V. inaequalis with the highest sequence identity to AvrLm6 was unable to trigger a resistance response in Rlm6 carrying Brassica juncea. RNA-seq and qRT-PCR gene expression analyses, of in planta and in vitro grown V. inaequalis, has revealed that many of the AvrLm6-like genes are expressed during infection. An AvrLm6 homologue from V. inaequalis that is up-regulated during infection was shown (using a YFP-fusion protein construct to be localized to the sub-cuticular stroma during infection of apple hypocotyls.
Köhl, J.; Scheer, C.; Holb, I.J.; Masny, S.; Molhoek, W.M.L.
Apple scab, caused by Venturia inaequalis, is the most important disease in apple production, reducing yield and quality of fruit. Control of apple scab in commercial orchards currently depends on multiple applications of fungicides. The potential of the antagonistic isolate Cladosporium
Fitzgerald, A.; Kan, van J.A.L.; Plummer, K.M.
RNA-mediated gene silencing has been demonstrated in plants, animals, and more recently in filamentous fungi. Here, we report high frequency, RNA-mediated gene silencing in the apple scab fungus, Venturia inaequalis. The green fluorescent protein (GFP) transgene was silenced in a GFP-expressing
Full Text Available The effect of pre-leaf fall of 5% urea treatment on primary infection of apple by Venturia inaequalis, the cause of scab, was investigated in commercial apple orchards of McIntosh cv. in different regions of Poland, at Miłobądz, Sinołęka and Dąbrowice. Additionally, the development of pseudothecia and maturation of ascospores were evaluated in the spring on apple leaves of two cultivars (McIntosh and Gloster treated with 5% solution of urea. Microscopic observations of leaves showed that urea treatment significantly reduced the number of pseudothecia (by ca. 90% and ascospore production. Low number of ascospores after urea treatment has strongly affected primary infection of apple by the fungus in all tested orchards. Reduction of leaf infection on control trees was usually more than 30%. Also efficacy of chemical control of apple scab was significantly higher on plots treated with urea.
Strategic irrigation is a method to prevent Apple scab (Venturia inaequalis). It is performed by irrigating the orchard floor in dry periods during spring, 24 hours before rain forecast. Irrigating the old leaves on the orchard floor will elicit the release of ascospores, but due to the dry trees...... and the dry weather, the ascospores dry out without causing infections. The method relies on the occurrence of dry periods during the period of primary infection from April to mid-June. Experiments were carried out at the University of Copenhagen and in an unsprayed Danish organic orchard in 2014 and 2015....... Apple scab on fruit and leaves was reduced by strategic irrigation in ‘Elshof’ at the University field in both years. In the organic orchard the strategic irrigation reduced the infection of leaves by apple scab and Elsinoe leaf and fruit spot in some cultivars and some years. Studies of the ejection...
Full Text Available The eradicative effect of two strobilurin fungicides (kresoxim-methyl and trifloxystrobin and difenoconazole on activity of apple scab spots was studied in greenhouse and field conditions. The reaction of mycelium and sporulation of Venturia inaequalis after fungicides applications were observed in light and scanning electron microscope. Mixture of strobilurin fungicide and difenoconazole applied twice, in 5 days interval, gave the best eradicative effect. The inhibition of sporulation was long lasting and it was observed even 3 and 5 weeks after treatments. The conidiophores, conidia and mycelium were damaged. Also difenoconazole showed good eradicative activity, in field condition up to 5 weeks after application. Trifloxystrobin significantly reduced the number of active scab lesions and the effect was visible even 3 weeks after treatment. Kresoxim-methyl in both tested doses (0,2 and 0,3 kg/ha was slightly less effective.
Full Text Available Venturia inaequalis is a common apple disease in Serbia and its intensity depends on weather conditions. The most successful method of combating apple scab is to use a lower dose of an active ingredient and increase its effectiveness by adding substances that do not cause environmental damage. The effectiveness of a fungicide mixture of captan and potassium phosphite against V. inaequalis was investigated in apple orchards in 2008 and 2009. A relevant EPPO standard method was used in all trials. Captan 50 WP was used as a standard fungicide. In order to determine the exact conditions marking the onset of apple infection, key meteorological conditions were monitored in the orchards using an automated iMetos weather station and a Lufft electronic instrument. The results showed high efficacy of the tested fungicides which remained similar in both years of investigation. The intensity of leaf infection after treatment with the mixture of captan and potassium phosphite was 0.7-2.4%, while fruit infection was 0.5-3.0%. The efficacy of this mixture ranged from 96.3-97.9% on leaves and 87.4-98.7% on fruits. The standard fungicide Captan 50 WP showed an efficacy ranging from 95.3-96.7% on leaves and from 87.8-99.3% on fruits. No statistically significant differences were found between the fungicide tested and the standard fungicide.
Khalil, Mohammed N A; Beuerle, Till; Müller, Andreas; Ernst, Ludger; Bhavanam, Vijaya B R; Liu, Benye; Beerhues, Ludger
Aucuparin is the most widely distributed biphenyl phytoalexin in the rosaceous subtribe Pyrinae, which includes the economically important fruit trees apple and pear. The biphenyl scaffold is formed by biphenyl synthase, which catalyzes biosynthesis of 3,5-dihydroxybiphenyl. Conversion of this precursor to aucuparin (3,5-dimethoxy-4-hydroxybiphenyl) was studied in cell cultures of Sorbus aucuparia after treatment with an elicitor preparation from the scab-causing fungus Venturia inaequalis. The sequence of the biosynthetic steps detected was O-methylation - 4-hydroxylation - O-methylation. The two alkylation reactions were catalyzed by distinct methyltransferases, which differed in pH and temperature optima as well as stability. Biphenyl 4-hydroxylase was a microsomal cytochrome P450 monooxygenase, whose activity was appreciably decreased by the addition of established P450 inhibitors. When fed to V. inaequalis-treated S. aucuparia cell cultures, radioactively labeled 3,5-dihydroxybiphenyl was not only incorporated into aucuparin but also into the dibenzofuran eriobofuran, the accumulation of which paralleled that of aucuparin. However, biphenyl 2'-hydroxylase activity proposed to be involved in dibenzofuran formation was detected in neither microsomes nor cell-free extracts in the presence of NADPH and 2-oxoglutarate, respectively. Nevertheless, a basis for studying biphenyl biosynthesis at the gene level is provided. Copyright © 2013 Elsevier Ltd. All rights reserved.
Arici, Serife Evrim; Kafkas, Ebru; Kaymak, Suat; Koc, Namik Kemal
Phenolic compounds play an important role in the plant defense mechanism and are responsible for antioxidant capacity in fruits and vegetables. It is known that the phenolics can determine in the leaves of plants which are resistant/susceptible to fungal infections. This study investigated the total phenolic compounds, content of shikimic acid from 33 different apple cultivars leaves infected with Venturia inaequalis [(Cke). Wint.] cultured in Fruit Research Station, in Egirdir, Isparta, Turkey. Leaves of apple cultivars were collected three times in an interval of 30 d from July to September in 2010, and analyzed using HPLC methods to detect changes in the amount of the phenolic compounds and shikimic acid. Total phenolic compounds and shikimic acid in resistant/moderate susceptible apple cultivars were higher than susceptible apple cultuvars, although not statistically different between resistant and susceptible apples. The content of shikimic acid was statistically higher only in the leaves of the domestic cultivar Ankara güzeli on all three dates. Recently, there have been increased studies trying to explain the resistance mechanism in plants. Natural resistance genes are investigated in some apple cultivars and new resistance varieties which have resistant genes are identified daily. Our study hold to determine the relationship between the phenolic compounds and the expression of resistance seems to be promising.
Bus, Vincent G M; Rikkerink, Erik H A; Caffier, Valérie; Durel, Charles-Eric; Plummer, Kim M
The apple scab (Venturia inaequalis-Malus) pathosystem was one of the first systems for which Flor's concept of gene-for-gene (GfG) relationships between the host plant and the pathogen was demonstrated. There is a rich resource of host resistance genes present in Malus germplasm that could potentially be marshalled to confer durable resistance against this most important apple disease. A comprehensive understanding of the host-pathogen interactions occurring in this pathosystem is a prerequisite for effectively manipulating these host resistance factors. An accurate means of identification of specific resistance and consistent use of gene nomenclature is critical for this process. A set of universally available, differentially resistant hosts is described, which will be followed by a set of defined pathogen races at a later stage. We review pertinent aspects of the history of apple scab research, describe the current status and future directions of this research, and resolve some outstanding issues. Copyright © 2011 by Annual Reviews. All rights reserved.
Muchembled, Jérôme; Deweer, Caroline; Sahmer, Karin; Halama, Patrice
The antifungal activity of seven essential oils (eucalyptus, clove, mint, oregano, savory, tea tree, and thyme) was studied on Venturia inaequalis, the fungus responsible for apple scab. The composition of the essential oils was checked by gas chromatography-mass spectrometry. Each essential oil had its main compound. Liquid tests were performed to calculate the IC 50 of essential oils as well as their majority compounds. The tests were made on two strains with different sensitivities to tebuconazole: S755, the sensitive strain, and rs552, the strain with reduced sensitivity. Copper sulfate was selected as the reference mineral fungicidal substance. IC 50 with confidence intervals were calculated after three independent experiments. The results showed that all essential oils and all major compounds had in vitro antifungal activities. Moreover, it was highlighted that the effectiveness of four essential oils (clove, eucalyptus, mint, and savory) was higher than copper sulfate on both strains. For each strain, the best activity was obtained using clove and eucalyptus essential oils. For clove, the IC 50 obtained on the sensitive strain (5.2 mg/L [4.0-6.7 mg/L]) was statistically lower than the IC 50 of reduced sensitivity strain (14 mg/L [11.1-17.5 mg/L]). In contrast, for eucalyptus essential oil, the IC 50 were not different with respectively 9.4-13.0 and 12.2-17.9 mg/L for S755 and rs552 strains. For mint, origano, savory, tea tree, and thyme, IC 50 were always the best on rs552 strain. The majority compounds were not necessarily more efficient than their corresponding oils; only eugenol (for clove) and carvacrol (for oregano and savory) seemed to be more effective on S755 strain. On the other hand, rs552 strain seemed to be more sensitive to essential oils than S755 strain. In overall, it was shown that essential oils have different antifungal activities but do not have the same antifungal activities depending on the fungus strain used.
Villani, Sara M; Cox, Kerik D
Quantitative (partial) and qualitative (complete) resistance responses to quinone outside inhibitor (QoI) fungicides have been documented for the apple scab pathogen Venturia inaequalis. Resistance monitoring efforts have traditionally focused on the detection of qualitative resistance based on a single point mutation, G143A, within the cytochrome b (cyt b) gene. In order to better understand the role of heteroplasmy of the cyt b gene in the QoI resistance response for isolates and populations of V. inaequalis, an allele-specific quantitative polymerase chain reaction was developed to quantify the relative abundance of the A143 (resistant) allele in 45 isolates of V. inaequalis with differing in vitro resistance responses to the QoI fungicide trifloxystrobin. Although a high relative abundance of the A143 allele (>62%) was associated with isolates with high resistance responses (50 to 100% relative growth on trifloxystrobin-amended medium), heteroplasmy of the cyt b gene was not the primary factor involved in isolates with moderate resistance responses (29 to 49% relative growth). The relative abundance of the A143 allele in isolates with moderate resistance to trifloxystrobin rarely exceeded 8%, suggesting that other resistance mechanisms are involved in moderate resistance and, therefore, that the Qol resistance response is polygenic. In research orchards where QoI fungicides failed to control apple scab (practical resistance), field trials were conducted to demonstrate the link between practical resistance and the abundance of the A143 allele. Relative abundance of the A143 allele in these orchard populations exceeded 20% in 2011 and 2012. Similarly, of the eight additional commercial orchards screened in 2011, the relative abundance of the A143 allele always exceeded 20% in those with QoI practical resistance. Although heteroplasmy of the cyt b gene did not entirely explain the response of isolates with moderate resistance to QoIs, the relative abundance of A
Deng, Cecilia H; Plummer, Kim M; Jones, Darcy A B; Mesarich, Carl H; Shiller, Jason; Taranto, Adam P; Robinson, Andrew J; Kastner, Patrick; Hall, Nathan E; Templeton, Matthew D; Bowen, Joanna K
Fungal plant pathogens belonging to the genus Venturia cause damaging scab diseases of members of the Rosaceae. In terms of economic impact, the most important of these are V. inaequalis, which infects apple, and V. pirina, which is a pathogen of European pear. Given that Venturia fungi colonise the sub-cuticular space without penetrating plant cells, it is assumed that effectors that contribute to virulence and determination of host range will be secreted into this plant-pathogen interface. Thus the predicted secretomes of a range of isolates of Venturia with distinct host-ranges were interrogated to reveal putative proteins involved in virulence and pathogenicity. Genomes of Venturia pirina (one European pear scab isolate) and Venturia inaequalis (three apple scab, and one loquat scab, isolates) were sequenced and the predicted secretomes of each isolate identified. RNA-Seq was conducted on the apple-specific V. inaequalis isolate Vi1 (in vitro and infected apple leaves) to highlight virulence and pathogenicity components of the secretome. Genes encoding over 600 small secreted proteins (candidate effectors) were identified, most of which are novel to Venturia, with expansion of putative effector families a feature of the genus. Numerous genes with similarity to Leptosphaeria maculans AvrLm6 and the Verticillium spp. Ave1 were identified. Candidates for avirulence effectors with cognate resistance genes involved in race-cultivar specificity were identified, as were putative proteins involved in host-species determination. Candidate effectors were found, on average, to be in regions of relatively low gene-density and in closer proximity to repeats (e.g. transposable elements), compared with core eukaryotic genes. Comparative secretomics has revealed candidate effectors from Venturia fungal plant pathogens that attack pome fruit. Effectors that are putative determinants of host range were identified; both those that may be involved in race-cultivar and host
Sankar Boxi, Siddhartha; Mukherjee, Khushi; Paria, Santanu
Chemical-based pesticides are widely used in agriculture to protect crops from insect infestation and diseases. However, the excessive use of highly toxic pesticides causes several human health (neurological, tumor, cancer) and environmental problems. Therefore nanoparticle-based green pesticides have become of special importance in recent years. The antifungal activities of pure and Ag doped (solid and hollow) TiO2 nanoparticles are studied against two potent phytopathogens, Fusarium solani (which causes Fusarium wilt disease in potato, tomato, etc) and Venturia inaequalis (which causes apple scab disease) and it is found that hollow nanoparticles are more effective than the other two. The antifungal activities of the nanoparticles were further enhanced against these two phytopathogens under visible light exposure. The fungicidal effect of the nanoparticles depends on different parameters, such as particle concentration and the intensity of visible light. The minimum inhibitory dose of the nanoparticles for V. inaequalis and F. solani are 0.75 and 0.43 mg/plate. The presence of Ag as a dopant helps in the formation of stable Ag-S and disulfide bonds (R-S-S-R) in cellular protein, which leads to cell damage. During photocatalysis generated •OH radicals loosen the cell wall structure and this finally leads to cell death. The mechanisms of the fungicidal effect of nanoparticles against these two phytopathogens are supported by biuret and triphenyl tetrazolium chloride analyses and field emission electron microscopy. Apart from the fungicidal effect, at a very low dose (0.015 mg/plate) the nanoparticles are successful in arresting production of toxic napthoquinone pigment for F. solani which is related to the fungal pathogenecity. The nanoparticles are found to be effective in protecting potatoes affected by F. solani or other fungi from spoiling.
Gladieux, Pierre; Zhang, Xiu-Guo; Róldan-Ruiz, Isabel; Caffier, Valérie; Leroy, Thibault; Devaux, Martine; Van Glabeke, Sabine; Coart, Els; Le Cam, Bruno
Evaluating the impact of plant domestication on the population structure of the associated pathogens provides an opportunity to increase our understanding of how and why diseases emerge. Here, we investigated the evolution of the population structure of the apple scab fungus Venturia inaequalis in response to the domestication of its host. Inferences were drawn from multilocus microsatellite data obtained from samples collected on (i) the Central Asian Malus sieversii, the main progenitor of apple, (ii) the European crabapple, Malus sylvestris, a secondary progenitor of apple, and (iii) the cultivated apple, Malus x domestica, in orchards from Europe and Central Asia. Using clustering methods, we identified three distinct populations: (i) a large European population on domesticated and wild apples, (ii) a large Central Asian population on domesticated and wild apples in urban and agricultural areas, and (iii) a more geographically restricted population in M. sieversii forests growing in the eastern mountains of Kazakhstan. Unique allele richness and divergence time estimates supported a host-tracking co-evolutionary scenario in which this latter population represents a relict of the ancestral populations from which current populations found in human-managed habitats were derived. Our analyses indicated that the domestication of apple induced a significant change in the genetic differentiation of populations of V. inaequalis in its centre of origin, but had little impact on its population dynamics and mating system. We discuss how the structure of the apple-based agrosystem may have restricted changes in the population structure of the fungus in response to the domestication of its host.
Full Text Available Scab (Venturia inaequalis is a very serious disease for apples causing up to 80% of loss in yield but there are only a few studies on postharvest quality of scab-resistant cultivars. In this study we evaluated the effect of 1-methylcyclopropene (1-MCP on fruit quality, total phenolic content, and antioxidant capacity after storage of four scab-resistant cultivars and compared to a standard cultivar, “Golden Delicious.” In general, ethylene production and respiration rates significantly differed among cultivars, between control and 1-MCP-treated fruits, and between storage duration regimes. 1-MCP treatment retarded fruit softening and lowered juice pH but storage effect on soluble solids and acidity depended on cultivar and 1-MCP treatment. Total phenolic content was significantly affected by storage duration and 1-MCP treatment. Antioxidant capacity of the four scab-resistant cultivars was either similar to or significantly higher than that of “Golden Delicious” with the 1-MCP-treated fruits having significantly higher antioxidant capacity than the nontreated fruits after storage. Our results clearly show that the quality of four scab-resistant cultivars was comparable to that of “Golden Delicious” and 1-MCP effect differed among cultivars. These differences need to be considered in developing storage regime to minimize quality deterioration during long-term storage.
Bengtsson, Marianne Vibeke; Wulff, Ednar Gadelha; Jørgensen, Hans Jørgen Lyngs
The effect of an extract of Yucca schidigera on the control and infection process of the apple scab pathogen, Venturia inaequalis, was examined and compared with the chemical resistance inducer, acibenzolar-S-methyl (ASM). In seedling assays, both materials significantly reduced apple scab symptoms...... and pathogen sporulation on leaves and both showed similar control efficacies as the reference treatment, sulphur. Whereas yucca extract and sulphur gave significant inhibition of conidial germination in vitro, ASM did not inhibit germination. Histopathological studies of the infection process of V. inaequalis...... in apple leaves showed that the yucca extract primarily acted by inhibiting pre-penetration events and penetration itself. In contrast, the ASM treatment significantly inhibited more stages of the infection process (pre-penetration, penetration and post-penetration events). These observations suggest...
Bus, V.G.M.; Laurens, F.N.D.; Weg, van de W.E.; Rusholme, R.L.; Gardiner, S.E.; Bassett, H.C.M.
The wild apple (Malus sieversii) is a large-fruited species from Central Asia, which is used as a source of scab resistance in cultivar breeding. Phytopathological tests with races of Venturia inaequalis were performed to differentiate scab-resistance genes in Malus as well as an avirulence gene in
Full Text Available Studies conducted during 2009-2013 at the Experimental Orchard located in the central region of Poland showed that the highest number of V. inaequalis pseudothecia occurred on ‘McIntosh’ and ‘Cortland’ leaves. A smaller number of pseudothecia was found on the leaves of the Alwa and Jonagold cultivars, but there were no statistical differences. The first discharges of ascospores were noted at a similar time on the leaves of all of the apple cultivars, usually at the end of March or in early April. For the forecasting of ascospore discharges and dates of critical periods, a simulation model by RIMpro was used. The number of critical periods and apple scab severity differed in each season. The most critical periods (above 20 were recorded in 2010 and 2013, which also corresponded with a high severity of apple scab. The number of infected leaves and fruits on the untreated trees of the very susceptible cultivar McIntosh reached nearly 100% during these seasons. In other years, the severity of the disease on the same apple trees was lower and amounted to 30-54% of infected leaves and 23-80% of infected fruits.
Full Text Available The fungal genus Venturia Sacc. (anamorph Fusicladium Bonord. includes plant pathogens that cause substantial economic damage to fruit crops worldwide. Although Venturia inaequalis is considered a model species in plant pathology, other Venturia spp. also cause scab on other fruit trees. Relative to the substantial research that has been conducted on V. inaequalis and apple scab, little research has been conducted on Venturia spp. affecting other fruit trees. In this review, the main characteristics of plant-pathogenic species of Venturia are discussed with special attention to V. inaequalis affecting apple, V. pyrina affecting European pear, V. nashicola affecting Asian pear, V. carpophila affecting peach and almond, Fusicladium oleagineum affecting olive, F. effusum affecting pecan, and F. eriobotryae affecting loquat. This review has two main objectives: (i to identify the main gaps in our knowledge regarding the biology and epidemiology of Venturia spp. affecting fruit trees; and (ii to identify similarities and differences among these Venturia spp. in order to improve disease management. A thorough review has been conducted of studies regarding the phylogenetic relationships, host ranges, biologies, and epidemiologies of Venturia spp. A multiple correspondence analysis (CA has also been performed on the main epidemiological components of these Venturia spp. CA separated the Venturia spp. into two main groups, according to their epidemiological behavior: the first group included V. inaequalis, V. pyrina, V. nashicola, and V. carpophila, the second F. oleagineum and F. eriobotryae, with F. effusum having an intermediate position. This review shows that Venturia spp. affecting fruit trees are highly host-specific, and that important gaps in understanding the life cycle exist for some species, including V. pyrina; gaps include pseudothecia formation, ascospore and conidia germination, and mycelial growth. Considering the epidemiological
I Danmark er der flere økologiske frugtplantager, der slet ikke anvender sprøjtning, og de ¿¿søger sprøjtefri metoder til at forhindre æbleskurv. I denne pilotundersøgelse blev vanding på strategiske tidspunkter testet til forebyggelse af skurv-infektion. I april-juni 2011 i fem økologiske frugtp...
In Denmark there are several organic orchards, that do not spray at all, and they seek non-spraying methods to prevent apple scab. In this pilot trial, irrigation with water at strategic moments was tested to prevent scab-infection. In April-June 2011 in five organic orchards we irrigated...... the orchard floor, to force the ascospores to be released. We irrigated with at least 0.2 mm of water in dry periods, at least 12 hours before rain forecast. The idea was to empty the stock of ascospores during dry spells, so they would dry out without infecting the leaves. To find the best strategic times...... for irrigation, we used the local weather forecast and the scab-warning programme Rimpro based on data from climate stations located in the orchards. In this first year of trial we experienced difficulties in spreading the water evenly. A water wagon turned out to work better than sprinklers. We found...
Gopaljee Jha; Karnika Thakur; Priyanka Thakur
Venturia inaequalis is the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.
Full Text Available Venturia inaequalis is the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.
Hyun Seok Koh
Full Text Available The fungus Venturia nashicola is the causal agent of scab on Asian pears. For the rapid and reliable identification as well as sensitive detection of V. nashicola, a PCR-based technique was developed. DNA fingerprints of three closely related species, V. nashicola, V. pirina, and V. inaequalis, were obtained by random amplified polymorphic DNA (RAPD analysis. Two RAPD markers specific to V. nashicola were identified by PCR, after which two pairs of sequence characterized amplified region (SCAR primers were designed from the nucleotide sequences of the markers. The SCAR primer pairs, designated as D12F/D12R and E11F/E11R, amplified 535-bp and 525-bp DNA fragments, respectively, only from genomic DNA of V. nashicola. The specificity of the primer sets was tested on strains representing three species of Venturia and 20 fungal plant pathogens. The nested PCR primer pair specific to V. nashicola was developed based on the sequence of the species-specific 525-bp DNA fragment amplified by primer set E11F/E11R. The internal primer pair Na11F/Na11R amplified a 235-bp fragment from V. nashicola, but not from any other fungal species tested. The nested PCR assay was sensitive enough to detect the specific fragment in 50 fg of V. nashicola DNA.
Koh, Hyun Seok; Sohn, San Ho; Lee, Young Sun; Koh, Young Jin; Song, Jang Hoon; Jung, Jae Sung
The fungus Venturia nashicola is the causal agent of scab on Asian pears. For the rapid and reliable identification as well as sensitive detection of V. nashicola, a PCR-based technique was developed. DNA fingerprints of three closely related species, V. nashicola, V. pirina, and V. inaequalis, were obtained by random amplified polymorphic DNA (RAPD) analysis. Two RAPD markers specific to V. nashicola were identified by PCR, after which two pairs of sequence characterized amplified region (SCAR) primers were designed from the nucleotide sequences of the markers. The SCAR primer pairs, designated as D12F/D12R and E11F/E11R, amplified 535-bp and 525-bp DNA fragments, respectively, only from genomic DNA of V. nashicola. The specificity of the primer sets was tested on strains representing three species of Venturia and 20 fungal plant pathogens. The nested PCR primer pair specific to V. nashicola was developed based on the sequence of the species-specific 525-bp DNA fragment amplified by primer set E11F/E11R. The internal primer pair Na11F/Na11R amplified a 235-bp fragment from V. nashicola, but not from any other fungal species tested. The nested PCR assay was sensitive enough to detect the specific fragment in 50 fg of V. nashicola DNA.
Caffier, V.; Lasserre-Zuber, P.; Giraud, M.; Lascostes, M.; Sievenard, R.; LeMarquand, A.; Weg, van de W.E.; Expert, P.; Denancé, C.
Theoretical approaches predict that host quantitative resistance selects for pathogens with a high level of pathogenicity, leading to erosion of the resistance. This process of erosion has, however, rarely been experimentally demonstrated. To investigate the erosion of apple quantitative resistance
Awanchiri, Simon Suh; Trinh-Van-Dufat, Hanh; Shirri, Jovita Chi; Dongfack, Marlise Diane J; Nguenang, Guy Merlin; Boutefnouchet, Sabrina; Fomum, Zacharias T; Seguin, Elisabeth; Verite, Philippe; Tillequin, François; Wandji, Jean
The air-dried stems and ripe fruit of Drypetes inaequalis Hutch. (Euphorbiaceae) were studied. Four triterpene derivatives, characterized as lup-20(29)-en-3beta,6alpha-diol, 3beta-acetoxylup-20(29)-en-6alpha-ol, 3beta-caffeoyloxylup-20(29)-en-6alpha-ol and 28-betad-glucopyranosyl-30-methyl 3beta-hydroxyolean-12-en-28,30-dioate along with 10 known compounds were isolated from the whole stems. One triterpene, characterized as 3alpha-hydroxyfriedelan-25-al along with six known compounds were isolated from the ripe fruit. Their structures were established on the basis of spectroscopic analysis and chemical evidence. The triterpenes were tested for antimicrobial activity against some Gram-positive and Gram-negative bacteria, and two of them appeared to be modestly active.
Dong, J.; Fernandez Fueyo, E.; Li, Jingbo; Guo, Zheng; Renirie, Rokus; Wever, Ron; Hollmann, F.
The vanadium-dependent chloroperoxidase from Curvularia inaequalis is a stable and efficient biocatalyst for the hydroxyhalogenation of a broad range of alkenes into halohydrins. Up to 1 200 000 TON with 69 s−1 TOF were observed for the biocatalyst. A bienzymatic cascade to yield epoxides as
Gusberti, Michele; Gessler, Cesare; Broggini, Giovanni A L
Ontogenic scab resistance in apple leaves and fruits is a horizontal resistance against the plant pathogen Venturia inaequalis and is expressed as a decrease in disease symptoms and incidence with the ageing of the leaves. Several studies at the biochemical level tried to unveil the nature of this resistance; however, no conclusive results were reported. We decided therefore to investigate the genetic origin of this phenomenon by performing a full quantitative transcriptome sequencing and comparison of young (susceptible) and old (ontogenic resistant) leaves, infected or not with the pathogen. Two time points at 72 and 96 hours post-inoculation were chosen for RNA sampling and sequencing. Comparison between the different conditions (young and old leaves, inoculated or not) should allow the identification of differentially expressed genes which may represent different induced plant defence reactions leading to ontogenic resistance or may be the cause of a constitutive (uninoculated with the pathogen) shift toward resistance in old leaves. Differentially expressed genes were then characterised for their function by homology to A. thaliana and other plant genes, particularly looking for genes involved in pathways already suspected of appertaining to ontogenic resistance in apple or other hosts, or to plant defence mechanisms in general. IN THIS WORK, FIVE CANDIDATE GENES PUTATIVELY INVOLVED IN THE ONTOGENIC RESISTANCE OF APPLE WERE IDENTIFIED: a gene encoding an "enhanced disease susceptibility 1 protein" was found to be down-regulated in both uninoculated and inoculated old leaves at 96 hpi, while the other four genes encoding proteins (metallothionein3-like protein, lipoxygenase, lipid transfer protein, and a peroxidase 3) were found to be constitutively up-regulated in inoculated and uninoculated old leaves. The modulation of the five candidate genes has been validated using the real-time quantitative PCR. Thus, ontogenic resistance may be the result of the
Full Text Available Ontogenic scab resistance in apple leaves and fruits is a horizontal resistance against the plant pathogen Venturia inaequalis and is expressed as a decrease in disease symptoms and incidence with the ageing of the leaves. Several studies at the biochemical level tried to unveil the nature of this resistance; however, no conclusive results were reported. We decided therefore to investigate the genetic origin of this phenomenon by performing a full quantitative transcriptome sequencing and comparison of young (susceptible and old (ontogenic resistant leaves, infected or not with the pathogen. Two time points at 72 and 96 hours post-inoculation were chosen for RNA sampling and sequencing. Comparison between the different conditions (young and old leaves, inoculated or not should allow the identification of differentially expressed genes which may represent different induced plant defence reactions leading to ontogenic resistance or may be the cause of a constitutive (uninoculated with the pathogen shift toward resistance in old leaves. Differentially expressed genes were then characterised for their function by homology to A. thaliana and other plant genes, particularly looking for genes involved in pathways already suspected of appertaining to ontogenic resistance in apple or other hosts, or to plant defence mechanisms in general. IN THIS WORK, FIVE CANDIDATE GENES PUTATIVELY INVOLVED IN THE ONTOGENIC RESISTANCE OF APPLE WERE IDENTIFIED: a gene encoding an "enhanced disease susceptibility 1 protein" was found to be down-regulated in both uninoculated and inoculated old leaves at 96 hpi, while the other four genes encoding proteins (metallothionein3-like protein, lipoxygenase, lipid transfer protein, and a peroxidase 3 were found to be constitutively up-regulated in inoculated and uninoculated old leaves. The modulation of the five candidate genes has been validated using the real-time quantitative PCR. Thus, ontogenic resistance may be the result
Beukeboom, LW; Pijnacker, LP; Traut, W.
Both arrhenotokous and thelytokous reproduction are known to occur in the parasitoid wasp Venturia canescens. The cytological mechanism of thelytoky was previously reported to involve the formation of a restitution metaphase after the reduction division, but the exact nature of the subsequent
Venturia effusa is the causal agent of pecan scab, the most prevalent disease of pecan in the southeastern US. Venturia effusa is currently only known to reproduce asexually, yet the genetic diversity among populations of pecan scab suggest it is a sexually reproducing pathogen. Analysis of the mati...
Pecan scab caused by Venturia effusa is widespread across southwest USA and epidemics can result in catastrophic yield loss. Venturia effusa reproduces asexually during the active phase of the disease cycle (spring through summer) with no evidence of a sexual cycle. Yet, genetic diversity among popu...
Thiel, A.; Driessen, G.J.J.; Hoffmeister, T.S.
The parasitic wasp, Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), has two reproductive modes, namely, thelytoky or arrhenotoky, and occurs in habitats with highly variable or relatively stable host abundances, respectively. Since information processing is costly, we expected that
Schneider, MV; Driessen, G; Beukeboom, LW; Boll, R; van Eunen, K; Selzner, A; Talsma, J; Lapchin, L
In the solitary parasitoid wasp Venturia canescens both arrhenotokously (sexual) and thelytokously (parthenogenetical) reproducing individuals occur sympatrically. We found in the laboratory that thelytokous wasps are able to mate, receive and use sperm of arrhenotokous males. Using nuclear
Malnoy, M; Reynoird, J P; Borejsza-Wysocka, E E; Aldwinckle, H S
Rather than using a constitutive promoter to drive transgenes for resistance against fungal and bacterial diseases in genetic engineering of apple (Malus x domestica) cultivars, a promoter induced only after infection was preferred. The ability of the Pgst1 promoter from potato (Solanum tuberosum L.) to drive expression of the gusA reporter gene was determined in two genotypes of apple: the fruit cultivar Royal Gala and the M.26 rootstock. beta-Glucuronidase activity in the transgenic lines grown in a growth chamber was determined quantitatively using fluorometric assays and compared to the activity in Cauliflower Mosaic Virus (CaMV) 35S promoter-driven transgenic lines. In both apple genotypes, the Pgst1 promoter exhibited a low level of expression after bacterial and fungal inoculation compared to the level obtained with the PCaMV35S promoter (15% and 8% respectively). The Pgst1 promoter was systematically activated in apple at the site of infection with a fungal pathogen. It was also activated after treatment with salicylic acid, but not after wounding. Taken together, these data show that, although the Pgst1 promoter is less active than the PCaMV35S promoter in apple, its pathogen responsiveness could be useful in driving the expression of transgenes to promote bacterial and fungal disease resistance.
Fernández-Fueyo, E.; van Wingerden, M.; Renirie, R.; Wever, R.; Ni, Y.; Holtmann, D.; Hollmann, F.
The vanadium-dependent chloroperoxidase from Curvularia inaequalis is an efficient biocatalyst for the in situ generation of hypohalous acids and subsequent electrophilic oxidn./halogenation reactions. Esp., its superb activity and stability under operational conditions make it an attractive
Full Text Available A new species of Venturia (V. chinensis is described and illustrated from the leaves of Lonicera praeflorens collected from Lesser Khingan Mountains, the northeast China. It is characterized by habitat saprobic; ascomata small-sized, solitary or scattered, superficial, subglobose to citriform, wall black, papillate, ostiolate, covered with setae; peridium thin; hamathecium evanescent in mature ascomata; asci 8-spored, bitunicate, fissitunicate, oblong to obclavate, with or without a short, knob-like pedicel; ascospores ellipsoidal, olivaceous pale brown, 1-septate, ascospore wall thin, smooth. Comparisons of V. chinensis with V. lonicerae (another species on Lonicera caerulea and other species of Venturia lead to the conclusion that collected taxon is new. Its relationships with other species of Venturia are discussed based on morphology and 28S nrDNA and ITS nrDNA sequence comparisons.
Bimal Sajeewa Amaradasa
Full Text Available Buffalograss (Bouteloua dactyloides is a low maintenance United States native turfgrass species with exceptional drought, heat and cold tolerance. Leaf spot caused by Curvularia inaequalis negatively impacts buffalograss visual quality. Two leaf spot susceptible and two resistant buffalograss lines were challenged with C. inaequalis. Samples were collected from treated and untreated leaves when susceptible lines showed symptoms. Transcriptome sequencing was done and differentially expressed genes were identified. Approximately 27 million raw sequencing reads were produced per sample. More than 86% of the sequencing reads mapped to an existing buffalograss reference transcriptome. De novo assembly of unmapped reads was merged with the existing reference to produce a more complete transcriptome. There were 461 differentially expressed transcripts between the resistant and susceptible lines when challenged with the pathogen and 1552 in its absence. Previously characterized defense-related genes were identified among the differentially expressed transcripts. Twenty one resistant line transcripts were similar to genes regulating pattern triggered immunity and 20 transcripts were similar to genes regulating effector triggered immunity. There were also nine up-regulated transcripts in resistance lines which showed potential to initiate systemic acquired resistance (SAR and three transcripts encoding pathogenesis-related proteins which are downstream products of SAR. This is the first study characterizing changes in the buffalograss transcriptome when challenged with C. inaequalis.
Full Text Available Possibility of V. inaequalis control on apple variety Idared was evaluated by ecologically acceptable products such as inorganic fungicides and acidified clays. The obtained results were compared with common, chemical protection. Year 2009 was one of the unfavorable for V. inaequalis, and 2010 was extremely favorable for apple scab development. Accordingly, in 2009 intensity of infection on apple leaves and fruits in control variant was low (leaves 15,4-34,9%; fruits 0-23,8%. In 2010 infection intensity on leaves and fruits was high (leaves 81,2%; fruits 100%. During period 2009-2010, in these different environmental conditions, common chemical protection showed high efficacy (leaves 96,2-100%; fruits 97,5-100%. High efficacy level in control of V. inaequalis on leaves of 87,4-99,7% was achieved also in variants in which copper products were applied in low concentration of 0,05%. It should be noted that in the most critical period, in April and May of 2010, the treatmentswere carried out in 5-6 days interval. Copper products showed differing efficacy on fruits (48,5-90,2%. In 2009 which is considered as one of the unfavorable for V. inaequalis development, product Ulmasud B applied alone on leaves was less efficiacy (51,8-58,6%, than on fruits (87,8%. In the same year, efficacy of this product in combination with sulfur, was better (leaves 71,4-76,6%; fruits 86,6. In 2010, which was especially rainy and favourablefor spreading the disease, efficiacy of mention combination of products didn,t satisfy (leaves 44,8%; fruits 41,0%. In the system of organic production, during vegetation period, program of apple protection in control of V. inaequalis should be supplemented by use of low concentrations of copper products (0,05% and by various alternative products of different action mechanisms,such as mineral clays, sulfur products etc. These researches should be continued.
Calenge, F.; Faure, A.; Goerre, M.; Gebhardt, C.; Weg, van de W.E.; Parisi, L.; Durel, C.E.
The ABC model for floral development was proposed more than 10 years ago and since then many studies have been performed on model species, such as Arabidopsis thaliana, Antirrhinum majus, and many other species in order to confirm this hypothesis. This led to additional information on flower
Foray, Vincent; Gibert, Patricia; Desouhant, Emmanuel
Environmental variability is expected to be important in shaping performance curves, reaction norms of phenotypic traits related to fitness. Models predict that the breadth of performance curves should increase with environmental variability at the expense of maximal performance. In this study, we compared the thermal performance curves of two sympatric populations of the parasitoid Venturia canescens that were observed under contrasting thermal regimes in their respective preferred habitats and differing in their modes of reproduction. Our results confirm the large effect of developmental temperature on phenotypic traits of insects and demonstrate that thelytokous and arrhenotokous wasps respond differently to temperature during development, in agreement with model predictions. For traits related to fecundity, thelytokous parasitoids, which usually occur in stable thermal conditions, exhibit specialist performance curves, maximising their reproductive success under a restricted range of temperature. In contrast, arrhenotokous parasitoids, which occur in variable climates, exhibit generalist performance curves, in keeping with the hypothesis "jack of all temperatures, master of none".
Chudek, J A; Crook, A M; Hubbard, S F; Hunter, G
Nuclear magnetic resonance microscopy was used to image the parasitoid wasp Venturia canescens (Hymenoptera: Ichneumonidae) within larval and pupal instars of its host, the Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae). The images were obtained using gradient-echo and chemical shift selective pulse sequences and clearly showed the location and shapes of the parasitoid as it developed from the L1 larva to a pupal stage within the host. The digestive, nervous, and tracheal systems of the host were identified and changes were observed as the host underwent metamorphosis. Destruction of the host tissues by the parasitoid was visible. It was found that the parasitoid first ate the fat body and digestive system of the host, allowing the host to continue to grow, and only progressed to the vital organs when its own development had neared pupation.
Kemp, H.; Maas, van der M.P.; Voorrips, R.E.; Groenwold, R.; Weg, van de W.E.
Durable resistance to scab (Venturia inaequalis) of newly introduced cultivars is needed to achieve a considerable reduction of pesticide use. However, the assessment in the field on the level and durability of scab resistance is time and space consuming. A proper and fast indoor test should be a
Jong, de P.F.; Scholten-Grit, G.; Anbergen, R.H.N.; Heijne, B.
Binnen de biologische fruitteelt is het aantal gewasbeschermingsmiddelen dat toegepast mag worden zeer beperkt. De meest belangrijke ziekte waar tegen bestreden moet worden, is schurft (Venturia inaequalis). Het middel zwavel is het meest toegepaste fungicide dat op dit moment wordt ingezet op
Köhl, J.; Heijne, B.; Hockenhull, J.; Lindhard Pedersen, H.; Trapman, M.; Eiben, U.; Tamm, L.
The objective of REPCO is to contribute to the replacement of copper fungicides in organic agriculture by new measures for control of downy mildew (Plasmopara viticola) in grapevine and scab (Venturia inaequalis) in apple. Both major European organic crops strongly depend on copper fungicides.
Khanizadeh, S.; Groleau, Y.; Levasseur, A.; Carisse, O.; Rekika, D.; DeEll, J.; Prive, J.P.; Alli, I.; Kemp, H.
`SuperMac' (Malus xdomestica Borkh) is being released as a replacement for `Spartan', which is presently being grown in Eastern Canada for its excellent shelf life. However, it is susceptibility to scab [Venturia inaequalis (Cke) Wint.], the most common apple disease. This new cultivar produces
Köhl, J.; Scheer, C.; Holb, I.J.; Masny, S.; Molhoek, W.M.L.
Apple scab caused by Venturia inaequalis is the most important disease in apple production. Control of apple scab currently depends on the multiple applications of fungicides. The potential of the antagonist isolate Cladosporium cladosporioides H39, originating from a sporulating colony of V.
Kohl, J.; Molhoek, W.M.L.; Groenenboom-de Haas, L.; Goossen-van de Geijn, H.M.; Eiben, U.
Apple scab caused by Venturia inaequalis is a major disease in apple production. Scab epidemics during summer are driven by conidia produced only on apple leaves. In this situation, antagonists present in the phyllosphere may interfere with conidia of the pathogen during sporulation or infection.
Lindhard Pedersen, Hanne; Paaske, Klaus; Bengtsson, Marianne V.; Hockenhull, John
Apple scab, caused by the fungus Venturia inaequalis, is the disease that most often decreases yield and causes loss of fruit quality in organic apple production. Damage to the fruits consists of brown to black spots, but in some years and on some varieties attacks can result in small misshapen fruits, that are totally unsuitable for fresh consumption.
Lindhard, Hanne; Paaske, Klaus; Bengtsson, Marianne V.; Hockenhull, John
Apple scab, caused by the fungus Venturia inaequalis, is the disease that most often decreases yield and causes loss of fruit quality in organic apple production. Damage to the fruits consists of brown to black spots, but in some years and on some varieties attacks can result in small misshapen fruits, that are totally unsuitable for fresh consumption.
Bus, V.G.M.; Weg, van de W.E.; Peil, A.; Dunemann, F.; Zini, E.; Laurens, F.N.D.; Blazek, J.; Hanke, V.; Forsline, P.L.
'Antonovka' has long been recognised as a major source of scab (Venturia inaequalis) resistance useful for apple breeding worldwide. Both major gene resistances in the form of the Rvi10 and Rvi17 and quantitative resistance, collectively identified as VA, have been identified in different accessions
Broggini, G.A.L.; Durel, C.E.; Vergne, E.; Chevreau, E.; Fahrentrapp, J.; Vanblaere, T.; Peil, A.; Flachowsky, H.; Hanke, M.V.; Krens, F.A.; Schouten, H.J.; Gessler, C.
Swiss and more generally European apple (Malus × domestica) production is hampered by several diseases, the most destructive being fire blight, caused by Erwinia amylovora. On the other hand, there are apple scab, caused by Venturia inaequalis and powdery mildew, caused by Podosphaera leucotricha,
DR TONUKARI NYEROVWO
Jan 26, 2012 ... However, tea oil production is often affected by infection ... Infection with the Venturia inaequalis fungus enhanced the metabolism of phenolic compounds at the apple scab spot (Slatnar et al., 2010a , b). Meanwhile, synthesis of ..... resistance of cucumber seedlings to Botrytis cinerea Pers]. Ying Yong.
Joshi, S.G.; Soriano Soriano, J.M.; Kortstee, A.J.; Schaart, J.G.; Krens, F.A.; Jacobsen, E.; Schouten, H.J.
Most of the apple (Malus × domestica) growers are facing serious disease problems with apple scab which is caused by the fungus Venturia inaequalis. Developing a resistant variety in apple through classical breeding is very slow and inefficient. So, we aim at improving existing apple varieties
Schurftschimmel Venturia inaequalis vraagt maar liefst 70 procent van het middelengebruik in de fruitteelt. ‘Telers hebben ermee leren leven’, weet PPO-onderzoeker Bart Heijne. Hij is nauw betrokken bij een proef met vinasse, het nieuwste wapen tegen de vermaledijde Angstgegner van fruittelers. ‘De
Chizzali, Cornelia; Gusberti, Michele; Schouten, H.J.; Gessler, Cesare; Broggini, G.A.L.
Main conclusion: The expression of the apple scab resistance geneRvi6in different apple cultivars and lines is not modulated by biotic or abiotic factors.All commercially important apple cultivars are susceptible to Venturia inaequalis, the causal organism of apple scab. A limited number of apple
Final Activity Report: The objective of REPCO was to contribute to the replacement of copper fungicides in organic agriculture by new measures for control of downy mildew (Plasmopara viticola) in grapevine and scab (Venturia inaequalis) in apple. Both major European organic crops strongly depend on
plates and transferred to potato dextrose agar (PDA; Difco Inc., Detroit, Michigan) slants (test tubes placed at an angle during cooling to give a...species” was plated onto potato carrot agar (PCA; Dinghra and Sinclair 1985) and PDA and incubated at 25 °C under a grow light for 1 to 3 weeks to...are leaf, stem, and fruit pathogens of a variety of plants (Farr et al. 1989). Venturia inaequalis, for example, causes a serious disease of apples
Apples, which are the most cultivated fruit in France, are mainly endangered by the fungal pathogen Venturia inaequalis that cause apple scab disease on apple. This disease can be responsible of major products loss unless orchards are treated against apple scab. Nowadays in France, the phytopathological diseases management policies are encouraging growers to reduce considerably the use of pesticides, while keeping a high quality and yield level. In this context, one must understand better how...
Advances in Apple Transformation Technology to Confer Resistance to Fungal Diseases in Apple Crops: A Chilean Perspective Avances de la Tecnología de Transformación del Manzano para Conferir Resistencia a Enfermedades Fungosas en su Cultivo: Una Perspectiva Chilena
Full Text Available Apple (Malus domestica Borkh. is one of the most consumed fruit in the world. Genetic transformation is a key process to sustain this demand by permitting the potential enhancement of existing cultivars as well as the development of new cultivars resistant to pests, diseases, and storage problems that occur in the major production areas. This review summarizes the advances of genetic engineering applied to the development of resistant apple cultivars to fungus disease, with particular attention in the generation of apples resistant to Venturia inaequalis (Cooke G.Winter, the main phytosanitary problem that affects apple crops in Chile.La manzana (Malus domestica Borkh. es una de las frutas más consumidas en el mundo. La transformación genética es un proceso clave para sustentar esta demanda, permitiendo el mejoramiento potencial de los cultivares existentes, así como el desarrollo de nuevas variedades resistentes a plagas, enfermedades y problemas de almacenamiento que se originan en las zonas de producción más importantes. Esta revisión resume los avances de la ingeniería genética aplicada al desarrollo de variedades de manzana resistentes a enfermedades fungosas, con especial atención en la generación de manzanas resistentes a Venturia inaequalis (Cooke G.Winter, el principal problema fitosanitario que afecta a los cultivos de manzana en Chile.
Harvey, J.A.; Harvey, I.F.; Thompson, D.J.
Parasitoid wasps have long been considered excellent organisms in studies examining the evolution of reproductive and life- history strategies. In examining the lifetime reproductive success of parasitoids in the laboratory, most investigations have provided the insects with excess hosts and food,
Bastiaanse, Héloïse; Bassett, Heather C M; Kirk, Christopher; Gardiner, Susan E; Deng, Cecilia; Groenworld, Remmelt; Chagné, David; Bus, Vincent G M
Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most severe diseases of apple worldwide. It is the most studied plant-pathogen interaction involving a woody species using modern genetic, genomic, proteomic and bioinformatic approaches in both species. Although 'Geneva' apple was recognized long ago as a potential source of resistance to scab, this resistance has not been characterized previously. Differential interactions between various monoconidial isolates of V. inaequalis and six segregating F1 and F2 populations indicate the presence of at least five loci governing the resistance in 'Geneva'. The 17 chromosomes of apple were screened using genotyping-by-sequencing, as well as single marker mapping, to position loci controlling the V. inaequalis resistance on linkage group 4. Next, we fine mapped a 5-cM region containing five loci conferring both dominant and recessive scab resistance to the distal end of the linkage group. This region corresponds to 2.2 Mbp (from 20.3 to 22.5 Mbp) on the physical map of 'Golden Delicious' containing nine candidate nucleotide-binding site leucine-rich repeat (NBS-LRR) resistance genes. This study increases our understanding of the complex genetic basis of apple scab resistance conferred by 'Geneva', as well as the gene-for-gene (GfG) relationships between the effector genes in the pathogen and resistance genes in the host. © 2015 BSPP AND JOHN WILEY & SONS LTD.
Delalieux, Stephanie; Keulemans, Wannes; van Aardt, Jan; Schrevens, Eddie; Coppin, Pol
Early detection of biotic and abiotic stresses and subsequent steering of agricultural systems using hyperspectral sensors potentially could contribute to the pro-active treatment of production-limiting factors. Venturia inaequalis (apple scab) is an important biotic factor that can reduce yield in apple orchards. Previous hyperspectral research focused on (i) determining if Venturia inaequalis leaf infections could be differentiated from healthy leaves and (ii) investigating at which developmental stage Venturia inaequalis infection could be detected. Logistical regression and partial least squares discriminant analysis were used to select the hyperspectral bands that best define differences among treatments. It was clear that hyperspectral data provide the contiguous, high spectral resolution data that are needed to detect subtle changes in reflectance values between healthy and stressed vegetation. The research was extended to include tree-based modeling as an alternative classification method. Results suggested that good predictability could be achieved when classifying infected plants based on this supervised classification technique. It was concluded that the spectral domain around 1600 nm was best suited to discriminate between infected and non-infected leaves immediately after infection, while the visible spectral region became more important at a well-developed infection stage. Research was focused on young leaves, because of the decreased incidence of infection in older leaves, the so-called 'ontogenic resistance'. Additional research was performed to gain a better understanding of the processes occurring during the first days after leaf unfolding and to evaluate the natural spectral variability among leaves. An undisturbed 20-day growth profile was examined to assess variations in the reflectance spectra due to physiological changes at the different growth stages of the leaves. Results suggested that an accurate distinction could be made between
Full Text Available A possibility of using spectral methods for determining a nutritional status and detecting pathogens in apple-tree cvs. ’Jonagold’ and ’Idared’ was verified in an orchard and pot experiments in 2007–2010. Treatments differed in the fertilizer or fungicide dose. Leaf samples were collected from the experimental variants to determine nitrogen content and to measure spectral reflectance (spectrophotometer Avantes USB 2000 and chlorophyll fluorescence imaging (FluorCam. Results of the measurements were correlated to leaf analyses for nitrogen content in dry matter. At the same time, a health status (the occurrence of fungal pathogens Venturia inaequalis and Podosphaera leucotricha was assessed and changes of photochemical efficiency of PSII of infected leaves were evaluated. The parameters providing the best description of differences in the photosynthetic activity of leaves depending on treatments (parameter Fv/Fm and parameter GENTY, known as ΦPSII – effective quantum yield of PSII were selected. The values of correlation coefficients of Fv/Fm and ΦPSII depending on fertilization treatments were as follows: Fv/Fm: r = −0.4735, p<0.000089, α = 0.05; ΦPSII: r = 0.755; p < 0.00038, α = 0.05. Data obtained from measuring with a spectrophotometer was used for the calculation to normalized difference vegetation indices NDVI; a significant relationship was found for the index GNDVI (r = 0.4691, p < 0,0002, α = 0.05. The significant difference between healthy leaves and leaves infected by the pathogens V. inaequalis and P. leucotricha was confirmed using the spectrophotometer, and the largest differences in reflectances were found in wavelengths around 400 nm. The values of indices GNDVI, RNDVI and NDVI 450 obtained from measuring reflectance of leaves with symptoms of V. inaequalis and P. leucotricha infections were significantly lower compared to the indices of healthy leaves. The values of indices NDVI were as follows: GNDVI 0
Sciubba, Fabio; Di Cocco, Maria Enrica; Gianferri, Raffaella; Capuani, Giorgio; De Salvador, Flavio Roberto; Fontanari, Marco; Gorietti, Daniela; Delfini, Maurizio
Apple scab, caused by the fungus Venturia inaequalis, is the most serious disease of the apple worldwide. Two cultivars (Malus domestica), having different degrees of resistance against fungi attacks, were analyzed by (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy. Aqueous and organic extracts of both apple flesh and skin were studied, and over 30 metabolites, classified as organic acids, amino acids, carbohydrates, phenolic compounds, lipids, sterols, and other metabolites, were quantified by means of one-dimensional (1D) and two-dimensional (2D) NMR experiments. The metabolic profiles of the two apple cultivars were compared, and the differences were correlated with the different degrees of resistance to apple scab by means of univariate analysis. Levels of metabolites with known antifungal activity were observed not only to be higher in the Almagold cultivar but also to show different correlation patterns in comparison to Golden Delicious, implying a difference in the metabolic network involved in their biosynthesis.
Full Text Available Abstract Apple is a fruit crop cultivated worldwide. Apple orchards are exposed to a diverse set of environmental and biological factors that affect the productivity and sustainability of the culture. Many of the efforts and costs for apple production rely on reducing the incidence of fungal diseases, and one of the main diseases is apple scab caused by the fungus Venturia inaequalis. The economic impact of scab on apple productivity has guided many breeding programs to search for cultivars resistant to apple scab. Introgression from wild relatives has been successful to some extent, and genetic engineering for resistant cultivars has even been employed. This review presents the techniques used to the present time to obtain pathogen-resistant apple cultivars and introduces new biotechnological approaches based on plant plasmids that show promising results for delivering genetic traits with a short-term perspective.
Full Text Available The efficacy of several fungicide mixtures in controlling Venturia inaequalis in apple was evaluated in field trials. The efficacies of Flint Plus (trifloxystrobin + captan and Tercel (pyraclostrobin+ dithianon in comparison with standard fungicides Zato 50-WG (trifloxystrobin and Stroby + Delan (kresoxim-methyl + dithianon were tested in the localities Mihajlovac, Radmilovac and Landol in 2004 and 2005. Both tested fungicides exhibited high efficacy in controlling apple scab. There were significant differencies in the efficacies of Flint Plus (91.3-98.5% and Zato 50-WG (68.2% and 78.4%; and Tercel (88.7-93.5% and Stroby + Delan (77.9% and 82.1%. Our experiments showed that the investigated fungicide mixtures arehighly effective against V. inaqeulais, even under high disease pressure.
Full Text Available Biological efficacy of strobilurines (trifloxystrobin and kresoxim-methyl was evaluated to compare the effect of late treatments of apples against post-harvest diseases with the effect of widely used reference products (captan, tolylfluanid, dithianone, dodine. One treatment 3–4 weeks before the harvest was applied (1000 l/ha water. Tested and reference products were used in doses authorised in the Czech Republic against the apple scab (Venturia inaequalis. Strobilurines effectiveness overcame all the products compared and showed an effect on reduction of weight decrease during the storage. In total 8 field tests were performed in 2000–2004 were efficacy, effect on fruit quality and weight decrease during storage was assessed.
Marie De Gracia
Full Text Available Understanding evolutionary dynamics of pathogens during domestication of their hosts and rise of agro-ecosystems is essential for durable disease management. Here, we investigated changes in life-history traits of the fungal pathogen Venturia inaequalis during domestication of the apple. Life traits linked to fungal dispersal were compared between 60 strains that were sampled in domestic and wild habitats in Kazakhstan, the center of origin of both host and pathogen. Our two main findings are that transition from wild to agro-ecosystems was associated with an increase of both spore size and sporulation capacity; and that distribution of quantitative traits of the domestic population mostly overlapped with those of the wild population. Our results suggest that apple domestication had a considerable impact on fungal characters linked to its dispersal through selection from standing phenotypic diversity. We showed that pestification of V. inaequalis in orchards led to an enhanced allocation in colonization ability from standing variation in the wild area. This study emphasizes the potential threat that pathogenic fungal populations living in wild environments represent for durability of resistance in agro-ecosystems.
Galli, Paolo; Patocchi, Andrea; Broggini, Giovanni Antonio Lodovico; Gessler, Cesare
Scab caused by the pathogen Venturia inaequalis is considered the most important fungal disease of cultivated apple (Malus x domestica Borkh.). In all, 16 monogenic resistances against scab have been found in different Malus spp. and some of them are currently used in apple breeding for scab-resistant cultivars. However, the self incompatibility and the long generation time of Malus spp. together with the high standards of fruit quality demanded from the fresh market render the breeding of high-quality cultivars in apple a long and expensive task. Therefore, the cloning of disease resistance genes and the use of the cloned genes for the transformation of high-quality apple cultivars could be an approach to solve these drawbacks. We report the construction of a bacterial artificial chromosome (BAC) contig spanning the Rvi15 (Vr2) apple scab resistance locus using two GMAL 2473 BAC libraries. A single BAC clone of the contig was sufficient to span the resistance locus. The BAC clone was completely sequenced, allowing identification of a sequence of 48.6 kb going from the two closest markers (ARGH17 and 77G20RP) bracketing Rvi15 (Vr2). Analysis of the 48.6-kb sequence revealed the presence of three putative genes characterized by a Toll and mammalian interleukin-1 receptor protein nucleotide-binding site leucine-rich repeat structure. All three genes were found to be transcribed.
Lemaire, Christophe; De Gracia, Marie; Leroy, Thibault; Michalecka, Monika; Lindhard-Pedersen, Hanne; Guerin, Fabien; Gladieux, Pierre; Le Cam, Bruno
Plant pathogens adapt readily to new crop varieties in agrosystems, and it is crucial to understand the factors underlying the epidemic spread of new virulent strains if we are to develop more efficient strategies to control them. In this study we used multilocus microsatellite typing, molecular epidemiology tools and a large collection of isolates from cultivated, wild and ornamental apples to investigate the origin of new virulent populations of Venturia inaequalis, an ascomycete fungus causing apple scab on varieties carrying the Rvi6 resistance gene. We demonstrated a common origin at the European scale of populations infecting apples (Malus × domestica) carrying the Rvi6 resistance and Malus floribunda, the progenitor of the Rvi6 resistance. Demographic modeling indicated that the Rvi6-virulent lineage separated several thousands of years ago from populations infecting non-Rvi6 hosts, without detectable gene flow between the two lineages. These findings show that 'breakdowns' of plant resistance genes can be caused by the selection and migration of virulent genotypes from standing genetic variation maintained in environmental disease reservoirs, here ornamental crabapples. This work stresses the need to take better account of pathogen diversity in resistance screenings of breeding lines and in resistance deployment strategies, in order to enhance sustainable disease management. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
Rowan, Daryl D; Hunt, Martin B; Dimouro, Aurélie; Alspach, Peter A; Weskett, Rosemary; Volz, Richard K; Gardiner, Susan E; Chagné, David
Volatile flavor compounds from the fruit of the progeny of two apple (Malus x domestica) cultivars with distinctive flavor and volatile profiles, 'Royal Gala' and 'Granny Smith', were measured by headspace gas chromatography-mass spectrometry over two fruiting seasons. Principal component analysis separated the volatile profiles into two groups according to the amounts produced of butyl, 2-methybutyl, pentyl, and hexyl acetates and of ethyl butanoate, butanol, 2-methylbutanol, and hexanol. Fruit containing the four acetate esters clustered with the 'Royal Gala' parent and were scored more similar to 'Royal Gala' than to "Granny Smith' in flavor. Fruit clustering with the 'Granny Smith' parent contained higher levels of ethyl butanoate and alcohols. Levels of acetate esters correlated to levels of their alcohol precursors, and control of this trait segregated in Mendelian fashion. The locus was mapped to the top of 'Royal Gala' linkage group 2 close to the Rvi4 (Vh4) locus for resistance to Venturia inaequalis , the causal agent of apple scab.
Chloralictus versatus Chloralictus zephyrus Chrysogaster ontario Coccinella sanguinea Colletes inaequalis Colletes inaequalis Compsomyia...Chloralictus versatus Chloralictus zephyrus Chrysogaster ontario Coccinella sanguinea Colletes inaequalis Colletes inaequalis Compsomyia...Xylocopa. Ctenium floridanum (FL) (Florida Orange -Grass) wind pollinated Cecil Field Naval Air Station (Closed) G2, S2 Dicerandra radfordiana (GA
Timmermans, B.G.H.; Jansonius, P.J.
In 2010 and 2011 the amounts of leaf litter and ascospore production per unit of leaf litter area in 7 organic pear orchards throughout the Netherlands were measured. In one of the orchards, adapted managements strategies were implemented, being grass/clover that is grown as ground cover on the
Controle de pragas e doenças, maturação e qualidade de maçãs 'imperial gala' submetidas ao ensacamento Control of insect pests and diseases, maturity and quality of 'imperial gala' apples submitted to bagging
Full Text Available O objetivo deste trabalho foi avaliar a eficiência de diferentes embalagens no ensacamento de maçãs para o controle de pragas e doenças, e sua influência na maturação e qualidade dos frutos, em pomar sob sistema orgânico. O experimento foi conduzido em pomar com plantas de dez anos de idade da cultivar Imperial Gala, sobre porta-enxerto 'Marubakaido', com filtro EM-9, localizado no município de São Joaquim-SC, nas safras 2007/2008 e 2008/2009. Os frutos foram ensacados, após o raleio, com embalagens plásticas transparentes microperfuradas ou de tecido não texturizado (TNT. Frutos não ensacados constituíram o tratamento-controle. Na colheita, os frutos foram avaliados quanto aos danos provocados por mosca-das-frutas (Anastrepha fraterculus, mariposa-oriental (Grapholita molesta, lagarta-enroladeira (Bonagota salubricola e pulgão-lanígero (Eriosoma lanigerum, incidência das doenças sarna-da-macieira (Venturia inaequalis e podridão-amarga (Colletotrichum gloeosporioides, e atributos físico-químicos de maturação e qualidade e teor de cálcio (Ca nos frutos. O ensacamento, independentemente do tipo de material utilizado, reduziu os danos de insetos-praga, porém não foi eficiente no controle de doenças nos frutos. O ensacamento não comprometeu o desenvolvimento de coloração vermelha na casca e o teor de Ca nos frutos. De modo geral, o ensacamento antecipou o processo de maturação, caracterizado pela redução na firmeza de polpa e na textura da casca e da polpa, e pelo aumento no índice de iodoamido.This work was carried out to evaluate the efficiency of different fruit bagging materials to insect pests and diseases control, and its influence on maturity and quality of the fruits in an organic apple orchard. The experiment was conducted in an orchard with ten years old 'Imperial Gala' apple trees grafted on 'Marubakaido' rootstock (with a filter of EM-9, in São Joaquim, State of Santa Catarina, in 2007/08 and 2008
Szpyrka, Ewa; Walorczyk, Stanisław
Dissipation of fungicide difenoconazole (3-chloro-4-[(2RS,4RS;2RS,4SR)-4-methyl-2-(1H-1,2,4-triazol-1-ylmethyl)-1,3-dioxolan-2-yl]phenyl 4-chlorophenyl ether) was studied following its application on apples intended for production of baby food. The apples (varieties: Jonagold Decosta, Gala and Idared) were sprayed with the formulation to control pathogens causing fungal diseases: powdery mildew (Podosphaera leucotricha ELL et Ev./Salm.) and apple scab (Venturia inaequalis Cooke/Aderh.). A validated gas chromatography-based method with simultaneous electron capture and nitrogen phosphorus detection (GC-ECD/NPD) was used for the residue analysis. The analytical performance of the method was highly satisfactory, with expanded uncertainties ≤ 19% (a coverage factor, k = 2, and a confidence level of 95%). The dissipation of difenoconazole was studied in pseudo-first-order kinetic models (for which the coefficients of determination, R2, ranged between 0.880 and 0.977). The half-life of difenoconazole was 12-21 days in experiments conducted on three apple varieties. In these experiments, the initial residue levels declined gradually and reached the level of 0.01 mg kg-1 in 50-79 days. For the residue levels to remain below 0.01 mg kg-1 (the maximum acceptable concentration for baby foods), difenoconazole must be applied approximately 3 months before harvest, at a dose of 0.2 L ha-1 (50 g of an active ingredient per ha).
Full Text Available O objetivo deste trabalho foi avaliar a eficiência de diferentes embalagens no ensacamento de maçãs para o controle de pragas e doenças, e sua influência na maturação e qualidade dos frutos, em pomar sob sistema orgânico. O experimento foi conduzido em pomar com plantas de dez anos de idade da cultivar Imperial Gala, sobre porta-enxerto 'Marubakaido', com filtro EM-9, localizado no município de São Joaquim-SC, nas safras 2007/2008 e 2008/2009. Os frutos foram ensacados, após o raleio, com embalagens plásticas transparentes microperfuradas ou de tecido não texturizado (TNT. Frutos não ensacados constituíram o tratamento-controle. Na colheita, os frutos foram avaliados quanto aos danos provocados por mosca-das-frutas (Anastrepha fraterculus, mariposa-oriental (Grapholita molesta, lagarta-enroladeira (Bonagota salubricola e pulgão-lanígero (Eriosoma lanigerum, incidência das doenças sarna-da-macieira (Venturia inaequalis e podridão-amarga (Colletotrichum gloeosporioides, e atributos físico-químicos de maturação e qualidade e teor de cálcio (Ca nos frutos. O ensacamento, independentemente do tipo de material utilizado, reduziu os danos de insetos-praga, porém não foi eficiente no controle de doenças nos frutos. O ensacamento não comprometeu o desenvolvimento de coloração vermelha na casca e o teor de Ca nos frutos. De modo geral, o ensacamento antecipou o processo de maturação, caracterizado pela redução na firmeza de polpa e na textura da casca e da polpa, e pelo aumento no índice de iodoamido.
Malnoy, M; Jin, Q; Borejsza-Wysocka, E E; He, S Y; Aldwinckle, H S
The NPR1 gene plays a pivotal role in systemic acquired resistance in plants. Its overexpression in Arabidopsis and rice results in increased disease resistance and elevated expression of pathogenesis-related (PR) genes. An NPR1 homolog, MpNPR1-1, was cloned from apple (Malus x domestica) and overexpressed in two important apple cultivars, Galaxy and M26. Apple leaf pieces were transformed with the MpNPR1 cDNA under the control of the inducible Pin2 or constitutive Cauliflower mosaic virus (CaMV)35S promoter using Agrobacterium tumefaciens. Overexpression of MpNPR1 mRNA was shown by reverse transcriptase-polymerase chain reaction. Activation of some PR genes (PR2, PR5, and PR8) was observed. Resistance to fire blight was evaluated in a growth chamber by inoculation of the shoot tips of our own rooted 30-cm-tall plants with virulent strain Ea273 of Erwinia amylovora. Transformed Galaxy lines overexpressing MpNPR1 had 32 to 40% of shoot length infected, compared with 80% in control Galaxy plants. Transformed M26 lines overexpressing MpNPR1 under the control of the CaMV35S promoter also showed a significant reduction of disease compared with control M26 plants. Some MpNPR-overexpressing Galaxy lines also exhibited increased resistance to two important fungal pathogens of apple, Venturia inaequalis and Gymnosporangium juniperi-virginianae. Selected transformed lines have been propagated for field trials for disease resistance and fruit quality.
Full Text Available Natural compounds used as elicitors of systemic induced resistance offer new prospects to control pome fruit tree diseases. This review presents a new way of plant protection for pome fruit tree diseases as a potential response to the very high use of pesticides in commercial production with the view to reduce their negative side-effects on environment and human health. Work is focused on examples of use of elicitors from natural origin which induce systemic resistance for controlling two important diseases as apple scab (Venturia inaequalis and fire blight (Erwinia amylovora. Many factors limit today their practical use: their efficacy is only partial and in interaction with plants and environment; much work has to be done to improve the formulation and to determine doses and rates of application, the right phenologic application times, and finally they are often submitted to the normal high standards of Plant Protection Products Regulations which are long, very expensive and not adapted to compounds which can have a very complex composition. In other hands, this new way of plant protection presents many potential advantages: using relatively simple, not expensive, non toxic natural compounds with a good image; polyvalent and broad field of action; non-specific and multi-side action which offer a good durability of action; systemic action in the plants during a relative long period of time and the possibility to control difficult bacterial diseases and more surprisingly viral diseases. The multiple advantages presented offer valuable prospects for a better friend-environmentally way to control pome fruit diseases in the next future.
Gagnon, Patrick; Sheedy, Claudia; Rousseau, Alain N; Bourgeois, Gaétan; Chouinard, Gérald
Pesticide transport by surface runoff depends on climate, agricultural practices, topography, soil characteristics, crop type, and pest phenology. To accurately assess the impact of climate change, these factors must be accounted for in a single framework by integrating their interaction and uncertainty. This article presents the development and application of a framework to assess the impact of climate change on pesticide transport by surface runoff in southern Québec (Canada) for the 1981-2040 period. The crop enemies investigated were: weeds for corn (Zea mays); and for apple orchard (Malus pumila), 3 insect pests (codling moth [Cydia pomonella], plum curculio [Conotrachelus nenuphar], and apple maggot [Rhagoletis pomonella]), 2 diseases (apple scab [Venturia inaequalis], and fire blight [Erwinia amylovora]). A total of 23 climate simulations, 19 sites, and 11 active ingredients were considered. The relationship between climate and phenology was accounted for by bioclimatic models of the Computer Centre for Agricultural Pest Forecasting (CIPRA) software. Exported loads of pesticides were evaluated at the edge-of-field scale using the Pesticide Root Zone Model (PRZM), simulating both hydrology and chemical transport. A stochastic model was developed to account for PRZM parameter uncertainty. Results of this study indicate that for the 2011-2040 period, application dates would be advanced from 3 to 7 days on average with respect to the 1981-2010 period. However, the impact of climate change on maximum daily rainfall during the application window is not statistically significant, mainly due to the high variability of extreme rainfall events. Hence, for the studied sites and crop enemies considered, climate change impact on pesticide transported in surface runoff is not statistically significant throughout the 2011-2040 period. Integr Environ Assess Managem 2016;12:559-571. © Her Majesty the Queen in Right of Canada 2015; Published 2015 SETAC. © Her Majesty the
Full Text Available Organic apple production in Europe depends to a great extent on the use of copper fungicides for scab control (Venturia inaequalis. The objective of this 6-year study (2003-2008 conducted in Belgium was to determine measures for reducing the use of copper fungicides in organic apple production. The effectiveness of a 'during-infection' spray strategy using wettable sulphur (with or without copper, lime sulphur, potassium bicarbonate, silicon and five natural plant extracts (orange peel, soapbark, tea seed, quinoa seed and grapefruit seed for controlling primary scab was investigated in a split-plot field experiment. Four apple cultivars that express a gradient of partial scab resistance were included: a high scab-susceptible cultivar (cv. 'Pinova', a medium scab-susceptible cultivar (cv. 'Pirouette' and two old cultivars expressing low to very low scab susceptibility (cvs. 'Reinette Hernaut' and 'Reinette des Capucins'. Apart from these cultivars, four monogenic Vf scab-resistant cultivars (cvs. 'Initial', 'Topaz', 'Zvatava' and 'JN 20/33/58' were also included in the experimental orchard. In order to reduce the amount of fungicide required, two strategies were used: a specific spray timing involving spraying during the infection processes, before fungal penetration, determined by the RIMpro software warning system, and a tunnel sprayer machine for optimal treatment applications. Depending on the year, a total of 8-12 applications were made annually. Under field conditions that were highly conducive disease, low rates of elemental sulphur (≤ 40 kg.ha-1 per year combined with low rates of copper (≤ 2.1 kg.ha-1 per year provided the best scab control and reduced scab severity on the leaves and fruits by 85-100%, depending on the year and cultivar, compared with the untreated control. In most cases, the lime sulphur spray treatment, which used more elemental sulphur but did not use copper, provided a similar level of scab control to the
Full Text Available O objetivo deste trabalho foi avaliar a eficiência de embalagens de diferentes materiais para a proteção contra pragas e doenças e seu efeito sobre a qualidade físico-química, maturação e teor de cálcio (Ca em maçãs 'Fuji Suprema'. O experimento foi desenvolvido nas safras de 2007/2008 e 2008/2009, em pomar manejado sob o sistema orgânico, localizado na região de São Joaquim (SC. O pomar era composto por plantas de dez anos de idade da cultivar Fuji Suprema, sobre porta-enxerto 'Marubakaido', com interenxerto 'EM-9'. Depois do raleio manual, aproximadamente 40 dias após a plena floração, os frutos foram ensacados com embalagens plásticas transparentes microperfuradas ou de tecido não texturizado (TNT. Os frutos foram mantidos ensacados até a colheita. A testemunha foi constituída por frutos não ensacados. Na colheita, os frutos foram avaliados quanto aos danos provocados por mosca-das-frutas (Anastrepha fraterculus, mariposa oriental (Grapholita molesta e lagarta enroladeira (Bonagota salubricola. As doenças foram avaliadas pela incidência de sarna da macieira (Venturia inaequalis, podridão amarga (Colletotrichum gloeosporioides e podridão carpelar (Alternaria sp., Fusarium sp.. Também foi avaliada a incidência de distúrbios fisiológicos "russeting" e "bitter pit", atributos físico-químicos de maturação e qualidade e o teor de Ca nos frutos. Independentemente do tipo de embalagem verificou-se que o ensacamento é prática eficaz na proteção contra o ataque de insetos, mas não reduz a incidência e o desenvolvimento de doenças nos frutos. Na safra de 2008/2009, o ensacamento dos frutos aumentou o teor de Ca e reduziu a incidência de "bitter pit", e aumentou a incidência do "russeting". O ensacamento dos frutos antecipou a maturação, especialmente com embalagem plástica transparente microperfurada, e reduziu a coloração vermelha, especialmente com embalagem TNT.
Full Text Available Conodonts of the uppermost Uhaku, the Kukruse, and the lower Haljala stages (uppermost Darriwilian and lower Sandbian of Estonia are discussed. The distribution of conodonts within the Pygodus serra, P. anserinus, and Amorphognathus tvaerensis zones is considered on the basis of 2 outcrop and 15 drill core sections. Judging by the Global Stratotype Section, Fågelsång, Sweden, the base of the Upper Ordovician Series should be lower than the first appearance of A. tvaerensis. The Estonian material shows that elements of A. tvaerensis from the lowermost range of the species are of a morphotype similar to A. inaequalis. It is proposed that the A. inaequalis Subzone be upgraded to the A. inaequalis Zone. The best level for the Middle–Upper Ordovician boundary in Estonia is at the lower boundary of the Kukruse Stage below the appearance of A. tvaerensis and/or A. inaequalis.
Full Text Available Abstract. As a result of years of developing the breeding programme for creating novel sweet cherry cultivars in the Fruit Growing Institute (FGI, Plovdiv, a reach hybrid fund from first and second hybrid generation is created. Of the selected and propagated hybrids at a more advanced stage of testing are 11 hybrids along with three new cultivars of the FGI Plovdiv ('Kossara', 'Rosalina' and 'Trakiiska hrushtyalka' grafted on three rootstocks were tested for sensitivity to causers of economically important fungal diseases in sweet cherry - cherry leaf spot (Blumeriella jaapii (Rehm Arx, shothole blight (Stigmina carpophila (Lev. Ellis and brown rot (Monilinia fructigena (G. Wint Honey. The degree of infestation under field conditions is reported by determining the index of attack on leaves and fruit, using the formula of McKinney. As the most sensitive elites are outlined elite El.17-31 (to cherry leaf spot and elite El.17-136 (to shothole blight. The cultivars 'Kossara' and 'Trakiiska hrushtyalka' exhibit an average resistance to the three diseases, as the values for the index of infestation are lower or similar to those of standard cultivars 'Van' and 'Bing', while 'Rosalina' demonstrated sensitivity to shothole blight and brown rot. Interesting is the elite El.17- 37 demonstrating the least infestation of Blumeriella jaapii - 7.33% and Monilinia fructigena - 6.67%. The same has a set of valuable qualities as late maturing date and very large fruits with excellent sensory profile, making it a potential candidate cultivar.
Scab (caused by Venturia effusa) is the most destructive disease of pecan in the southeastern USA. The most widely used method to apply fungicide is air-blast (AB) sprayers. Aerially (A) applied sprays are also used, but the disease distribution and spray coverage of these two methods has not been c...
Venturia ovivenans nov. spec, and Strabotes rupelae nov. spec, are described. Both were reared from the rice stem borer Rupela albinella (Cr.) in Surinam (Sth. America). Strabotes abdominalis obscurus nov. subspec. is described from Columbia and a key is given to the known species of the Neotropic
Pecans are economically the most important native nut crop in the USA. Among the major concerns are the pecan weevil (Curculio caryae), pecan aphids, and diseases such as pecan scab, Venturia effusa. These pests are generally controlled with broad spectrum chemicals. The chemical pesticides can be...
Silver nanoparticles have been widely reported in literature due to their vast industrial application in different areas. In this work, we explored a simple procedure for the biosynthesis of silver nanoparticles at room temperature from the action of Curvularia inaequalis as reduction agent. The degree of aggregation and size of ...
Three species of the genus Podospora Cesati are described and illustrated. P. carpinicola, spec. nov., and P. inaequalis (Cain) Cain were isolated from dead leaves of Carpinus collected at Fontainebleau. The isolate of P. minicauda Faurel & Locquin-Linard was obtained from a soil sample from the
Patricia Ortiz-Bermudez; Ewald Srebotnik; Kenneth E. Hammel
Two fungal chloroperoxidases (CPOs), the heme enzyme from Caldariomyces fumago and the vanadium enzyme from Curvularia inaequalis, chlorinated 1-(4-ethoxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-dihydroxypropane, a dimeric model compound that represents the major nonphenolic structure in lignin. Both enzymes also cleaved this dimer to give 1-chloro-4-ethoxy-3-...
Patricia Ortiz-Bermudez; Kolby C. Hirth; Ewald Srebotnik; Kenneth E. Hammel
Soils and decayed plant litter contain significant quantities of chlorinated aromatic polymers that have a natural but largely unknown origin. We used cupric oxide ligninolysis coupled with gas chromatography/mass spectrometry to show that Curvularia inaequalis, a widely distributed litter ascomycete, chlorinated the aromatic rings of lignin in wood that it was...
Full Text Available The Mid-Carboniferous boundary in the Aladað Unit of the Central Taurides, previously delineated on the basis of foraminifers, is now further recognizable on the basis of conodonts. Latest Serpukhovian conodonts are assigned to the Rhachistognathus muricatus Zone, whereas the early Bashkirian forms correspond to the Declinognathodus inaequalis - Declinognathodus noduliferus Zone. Conodont assemblages discovered in the Taurides are comparable to those described from Mid-Carboniferous boundary sections in North America, Japan, southern Urals, southern China, Ukraine and Uzbekistan. The Mid-Carboniferous boundary is located at a horizon marked by the first appearance of Declinognathodus inaequalis, just above the last appearance of the conodont Gnathodus girtyi simplex. This horizon coincides with the boundary indicated by foraminiferal data.
Full Text Available Species in the genus Zygophiala are associated with sooty blotch and flyspeck disease on a wide range of hosts. In this study, 63 Zygophiala isolates collected from flyspeck colonies on a range of plants from several regions of China were used for phylogeny, host range and geographic distribution analysis. Phylogenetic trees were constructed on four genes--internal transcribed spacer (ITS, partial translation elongation factor 1-alpha (TEF, β-tubulin (TUB2, and actin (ACT--both individually and in combination. Isolates were grouped into 11 clades among which five new species, Z. emperorae, Z. trispora, Z. musae, Z. inaequalis and Z. longispora, were described. Species of Zygophiala differed in observed host range and geographic distribution. Z. wisconsinensis and Z. emperorae were the most prevalent throughout the sampled regions of China, whereas Z. trispora, Z. musae, Z. inaequalis and Z. longispora were collected only in southern China. The hosts of Z. wisconsinensis and Z. emperorae were mainly in the family Rosaceae whereas Z. trispora, Z. musae, Z. inaequalis and Z. longispora were found mainly on banana (Musa spp.. Cross inoculation tests provided evidence of host specificity among SBFS species.
Johnston, Peter R; Seifert, Keith A; Stone, Jeffrey K; Rossman, Amy Y; Marvanová, Ludmila
In advancing to one scientific name for fungi, this paper treats genera competing for use in the phylogenetically defined class Leotiomycetes except for genera of Erysiphales. Two groups traditionally included in the so-called "inoperculate discomycetes" have been excluded from this class and are also not included here, specifically Geoglossomycetes and Orbiliomycetes. A recommendation is made about the generic name to use in cases in which two or more generic names are synonyms or taxonomically congruent along with the rationale for the recommendation. In some cases the recommended generic name does not have priority or is based on an asexual type species, thus needs to be protected and ultimately approved according to Art. 57.2 of the International Code of Nomenclature for algae, fungi and plants (ICN). A table is presented listing all competing generic names and their type species noting the recommended generic name. New combinations are introduced for the oldest epithet in the recommended genus including Ascocalyx berenice, Ascoconidium purpurascens, Ascocoryne albida, A. trichophora, Blumeriella filipendulae, B. ceanothi, Botrytis arachidis, B. fritillariae-pallidoflori, Calloria urticae, Calycellina aspera, Dematioscypha delicata, Dermea abietinum, D. boycei, D. stellata, Diplocarpon alpestre, D. fragariae, Godroniopsis peckii, Grovesinia moricola, Heterosphaera sublineolata, Hyphodiscus brachyconium, H. brevicollaris, H. luxurians, Leptotrochila campanulae, Monilinia polystroma, Neofabraea actinidae, N. citricarpa, N. vagabunda, Oculimacula aestiva, O. anguioides, Pezicula brunnea, P. californiae, P. cornina, P. diversispora, P. ericae, P. melanogena, P. querciphila, P. radicicola, P. rhizophila, Phialocephala piceae, Pilidium lythri, Rhabdocline laricis, Streptotinia streptothrix, Symphyosirinia parasitica, S. rosea, Unguiculariopsis caespitosa, and Vibrissea laxa.
Full Text Available The investigations were made in the experimental sour cherry orchard from the Institute of Agriculture, Kyustendil, Bulgaria, during the period 2010-2014, in order to compare conventional and integrated sour cherry protection against cherry leaf spot and cherry fruit fly. Two variants were investigated, with two different treatment approaches for the control of cherry leaf spot and cherry fruit fly. Variant 1 – cherry leaf spot was controlled by protective treatments with dodin and tebuconazole + trifloxystrobin and cherry fruit fly was controlled by treatments with deltametrin and thiacloprid, independently of density. Variant 2 - cherry leaf spot was controlled by post-infection (curative treatments with tebuconazole + trifloxystrobin and cherry fruit fly was controlled by treatments based on biological threshold: 10-11 cherry fruit fly females caught in traps up to the moment for chemical treatment. It was established that Blumeriella japii can be successfully controlled by post-infection treatments and by this the number of insecticide treatments was reduced. The treatments against cherry fruit fly can be avoided or reduced when the attack control is based on the biological threshold established in the studied area.
Full Text Available Autochthonous genotypes of fruit species are very important source of genetic variability and valuable material for breeding work. Fruit Research Institute-Čačak has a long tradition of studying autochthonous genotypes of temperate fruits sporadically spread and preserved in some localities in Serbia. Over 2005-2006, the following properties of nine autochthonous sour cherry genotypes grown in Feketic region were investigated: flowering and ripening time, pomological properties, biochemical composition of fruits and field resistance to causal agents of cherry diseases - cherry leaf spot (Blumeriella jaapii (Rehm. v. Arx., shot-hole (Clasterosporium carpophilum (Lév. Aderh. and brown rot (Monilinia laxa /Ader et Ruhl./ Honey ex Whetz.. The genotypes were tested for the presence of Prune dwarf virus and Prunus necrotic ring spot virus. In majority of genotypes fruits were large, with exceptional organoleptical properties, whereas ripening time was in the first ten or twenty days of June. The highest fruit weight was observed in F-1 genotype (8.1 g. The highest soluble solids and total sugars content were found in F- 4 genotype (17.60% and 14.25%, respectively. As for field resistance to causal agents of diseases and good pomo-technological properties, F-1, F-2, F-3, F-7 and F-8 genotypes were singled out. [Projekat Ministarstva nauke Republike Srbije, br. TR31064
Full Text Available The composition of two fungicides: carbendazim 40% and captafol 40% gave very good to fair control of apple tree diseases. This formulation was used in field experiments against apple scab, bark canker fungi and bitter rot of apple fruits. The 0,06 per cent concentration was very effective against strains of Venturia inaequnlis tolerant and resistant to benzimidazole fungicides. The 0,1 per cent concentration gave very good control of Nectria galligena and Pezicula malicorticis and fair control of Stereum purpureum and Phvtophthora cactorum.
Full Text Available Growth and sporulation of phytopathogen microscopic fungi were studied under a static magnetic fi eld. The applied flux densities were 0,1, 0,5 and 1 mT. As a result of our experiments, the magnetic fi eld decreased the growth of colonies by 10 % using this fl ux density region. At the same time, the number of the developed conidia of Alternaria alternata and Curvularia inaequalis increased by 68-133 percent, but the number of Fusarium oxysporum conidia decreased by 79-83 percent.
Tatiana C. Pesenti
Full Text Available Tadarida brasiliensis (Geoffroy, 1824, the Brazilian free-tailed bat, is an insectivorous bat that occurs from southern United States of America to southern South America. In this study we present the first data on diversity of ectoparasitic mites of T. brasiliensis in Brazil. A compilation and analysis of the studies of mite diversity conducted in different points the geographic distribution this bat species are provided. The mites were collected from March 2010 to November 2011 on 160 T. brasiliensis adult bats captured in southern Brazil. Four species of mites have been found: Chiroptonyssus robustipes (Ewing, 1925, Ewingana longa (Ewing, 1938, Ewingana inaequalis (Radford, 1948, and specimens of Cheyletidae. Chiroptonyssus robustipes was the most prevalent species (100%, followed by E. longa (20%, E. inaequalis (10%, and specimens of Cheyletidae (1.25%. The data currently available show that C. robustipes parasitizes T. brasiliensis throughout its region of occurrence, and this mite is highly prevalent and abundant. The two species of Ewingana accompany the geographical distribution of T. brasiliensis, but with much lower prevalence and abundance.
Full Text Available At Fruit Research Institute in Čačak, major objectives of the work on breeding new sour cherry (Prunus cerasus L. cultivars are high cropping, large, high-quality fruits and resistance to causal agents of diseases and pests. As a result of the planned hybridization, more than 10,000 hybrid seedlings have been developed from about 40 cultivars within more than 110 parental combinations, among which are 'Čačanski rubin' ('Shasse Morello' x 'Köröser Weichsel' and 'Šumadinka' ('Köröser Weichsel' x 'Heimanns Konserven Weichsel' which have been named and released. Ten-year study of 11 hybrids, selected from the population of about 3,000 hybrid seedlings, gave four hybrids which have been singled out as elite (III/23, III/31, II/40 i XII/57. These hybrids are currently under procedure of being released as new cultivars. The paper presents two-year results of the study of ripening time, pomological properties, biochemical composition of fruits, and field resistance to causal agents of diseases and pests attacking the above named genotypes which were compared to standard cultivar 'Heimanns Konserven Weichsel'. In the studied hybrids, fruit weight, soluble solids content and sugars content were higher than in standard cultivar. In addition, they exhibit substantial field resistance to causal agents of brown rot (Monilinia laxa /Ader et Ruhl./ Honey ex Whetz., cherry leaf spot (Blumeriella jaapii (Rehm. v. Arx., shot-hole (Clasterosporium carpophilum (Lév. Aderh. and cherry fruit fly (Rhagoletis cerasi L. attack.
Full Text Available This study assessed the diversity and distribution of endophytic fungal communities associated with the leaves and stems of four vascular plant species in the High Arctic using 454 pyrosequencing with fungal-specific primers targeting the ITS region. Endophytic fungal communities showed high diversity. The 76,691 sequences obtained belonged to 250 operational taxonomic units (OTUs. Of these OTUs, 190 belonged to Ascomycota, 50 to Basidiomycota, 1 to Chytridiomycota, and 9 to unknown fungi. The dominant orders were Helotiales, Pleosporales, Capnodiales, and Tremellales, whereas the common known fungal genera were Cryptococcus, Rhizosphaera, Mycopappus, Melampsora, Tetracladium, Phaeosphaeria, Mrakia, Venturia, and Leptosphaeria. Both the climate and host-related factors might shape the fungal communities associated with the four Arctic plant species in this region. These results suggested the presence of an interesting endophytic fungal community and could improve our understanding of fungal evolution and ecology in the Arctic terrestrial ecosystems.
Full Text Available Genera of Phytopathogenic Fungi (GOPHY is introduced as a new series of publications in order to provide a stable platform for the taxonomy of phytopathogenic fungi. This first paper focuses on 21 genera of phytopathogenic fungi: Bipolaris, Boeremia, Calonectria, Ceratocystis, Cladosporium, Colletotrichum, Coniella, Curvularia, Monilinia, Neofabraea, Neofusicoccum, Pilidium, Pleiochaeta, Plenodomus, Protostegia, Pseudopyricularia, Puccinia, Saccharata, Thyrostroma, Venturia and Wilsonomyces. For each genus, a morphological description and information about its pathology, distribution, hosts and disease symptoms are provided. In addition, this information is linked to primary and secondary DNA barcodes of the presently accepted species, and relevant literature. Moreover, several novelties are introduced, i.e. new genera, species and combinations, and neo-, lecto- and epitypes designated to provide a stable taxonomy. This first paper includes one new genus, 26 new species, ten new combinations, and four typifications of older names.
Marin-Felix, Y; Groenewald, J Z; Cai, L; Chen, Q; Marincowitz, S; Barnes, I; Bensch, K; Braun, U; Camporesi, E; Damm, U; de Beer, Z W; Dissanayake, A; Edwards, J; Giraldo, A; Hernández-Restrepo, M; Hyde, K D; Jayawardena, R S; Lombard, L; Luangsa-Ard, J; McTaggart, A R; Rossman, A Y; Sandoval-Denis, M; Shen, M; Shivas, R G; Tan, Y P; van der Linde, E J; Wingfield, M J; Wood, A R; Zhang, J Q; Zhang, Y; Crous, P W
Genera of Phytopathogenic Fungi (GOPHY) is introduced as a new series of publications in order to provide a stable platform for the taxonomy of phytopathogenic fungi. This first paper focuses on 21 genera of phytopathogenic fungi: Bipolaris, Boeremia, Calonectria, Ceratocystis, Cladosporium, Colletotrichum, Coniella, Curvularia, Monilinia, Neofabraea, Neofusicoccum, Pilidium, Pleiochaeta, Plenodomus, Protostegia, Pseudopyricularia, Puccinia, Saccharata, Thyrostroma, Venturia and Wilsonomyces. For each genus, a morphological description and information about its pathology, distribution, hosts and disease symptoms are provided. In addition, this information is linked to primary and secondary DNA barcodes of the presently accepted species, and relevant literature. Moreover, several novelties are introduced, i.e. new genera, species and combinations, and neo-, lecto- and epitypes designated to provide a stable taxonomy. This first paper includes one new genus, 26 new species, ten new combinations, and four typifications of older names.
Pollock, Darren A
The Neotropical eurypine genus Thisiomorphus is revised, based on external structural features of adults. Twelve species are recognized, including the following eleven new species (type areas in parentheses): T. festivus (Panama, Colón Prov.), T. osaensis (Costa Rica, Puntarenas Prov.), T. davidsoni (Brazil, Chapada), T. inaequalis (Ecuador, Napo Prov.), T. caeruleus (Panama, Panamá Prov.), T. brasiliensis (Brazil, Amazonas), T. solisi (Costa Rica, Guanacaste Prov.), T. andrewsi (Panama, Chiriquí Prov.), T. bolivianus (Bolivia, Santa Cruz Dept.), T. curticornis (Ecuador, Sucumbíos Prov.), and T. convergens (Brazil, Pará). A key to the 13 described eurypine genera of Central and South American is provided, along with a key to species of Thisiomorphus. The keys are supplemented with images of habitus and selected structural features, and maps of known distributions are provided.
Full Text Available Capillary electrophoresis single-strand conformational polymorphism (CE-SSCP was explored as a fast and inexpensive method to differentiate both prokaryotic (blue-green and eukaryotic (green and brown algae. A selection of two blue-green algae (Nostoc muscorum and Anabaena inaequalis, five green algae (Chlorella vulgaris, Oedogonium foveolatum, Mougeotia sp., Scenedesmus quadricauda, and Ulothrix fimbriata, and one brown algae (Ectocarpus sp. were examined and CE-SSCP electropherogram “fingerprints” were compared to each other for two variable regions of either the 16S or 18S rDNA gene. The electropherogram patterns were remarkably stable and consistent for each particular species. The patterns were unique to each species, although some common features were observed between the different types of algae. CE-SSCP could be a useful method for monitoring changes in an algae species over time as potential shifts in species occurred.
Shimonishi, M; Kuwamoto, S; Inoue, H; Wever, R; Ohshiro, T; Izumi, Y; Tanabe, T
The cDNAs for a vanadium-dependent bromoperoxidase were cloned from a marine macro-alga, Corallina pilulifera. The open reading frame of one clone (bpo1) encoded a protein of 598 amino acids with a calculated molecular mass of 65312 Da in good agreement with that of 64 kDa determined for the native enzyme. The deduced amino acid sequence coincided well with partial sequences of peptide fragments of the enzyme. From the same cDNA library we also isolated another cDNA clone (bpo2) encoding a protein of 597 amino acids with an identity of about 90% to BPO1, suggesting a genetic diversity of the bromoperoxidase gene of C. pilulifera growing in a relatively narrow area. The carboxy-terminal 123 residues of the enzyme (BPO1) showed an identity of 45% to that of the marine macro-alga Ascophillum nodosum. The homology search of the sequences of bromoperoxidases from C. pilulifera (this study) and A. nodostum, and chloroperoxidase from the fungus Curvularia inaequalis indicated highly conserved sequences PxYxSGHA and LxxxxAxxRxxxGxHxxxD. Furthermore, it was found that the histidine residue directly bound to vanadium, other residues building up the metal center and catalytic histidine residue forming the active site of the chloroperoxidase from C. inaequalis are conserved in the primary structure of the bromoperoxidase from C. pilulifera. The cloned hpol was introduced into Escherichia coli, and the expressed PO1 was purified from the recombinant strain. The N-terminal amino acid sequence of the purified BPO1 was identical to the deduced sequence from the cDNA except the N-terminal methionine.
Jones, Thomas S; Bilton, Adam R; Mak, Lorraine; Sait, Steven M
Parasitoids face challenges by switching between host species that influence survival and fitness, determine their role in structuring communities, influence species invasions, and affect their importance as biocontrol agents. In the generalist parasitoid, Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), we investigated the costs in encapsulation, survival, and body size on juveniles when adult parasitoids switched from their original host, Plodia interpunctella (Hübner) (Lepidotera, Pyralidae) to a novel host, Ephestia kuehniella (Zeller) (Lepidoptera, Pyralidae), over multiple generations. Switching had an initial survival cost for juvenile parasitoids in the novel host, but increased survival occurred within two generations. Conversely, mortality in the original host increased. Body size, a proxy for fecundity, also increased with the number of generations in the novel host species, reflecting adaptation or maternal effects due to the larger size of the novel host, and therefore greater resources available to the developing parasitoid. Switching to a novel host appears to have initial costs for a parasitoid, even when the novel host may be better quality, but the costs rapidly diminish. We predict that the net cost of switching to a novel host for parasitoids will be complex and will depend on the initial reduction in fitness from parasitizing a novel host versus local adaptations against parasitoids in the original host. PMID:25691971
Szpyrka, Ewa; Walorczyk, Stanisław
Dissipation behaviour of simultaneously applied fungicides fluquinconazole and pyrimethanil was studied in/on apples intended for baby food production (cultivars Jonagold Decosta, Golden and Champion). The apples were sprayed at two dosages to control the pathogen Venturia inaedequalis (Cooke) Aderh. A validated gas chromatographic method (GC-ECD and GC-NPD) was used to determine the fungicides residues, the analytical performance of which was highly satisfactory with expanded uncertainties not higher than 15% (coverage factor k=2, confidence level 95%) The dissipation of the fungicide residues was fitted to the experimental data assuming pseudo first-order decay kinetics (R(2) between 0.897 and 0.992). To obtain the fungicide residues below 0.01 mg/kg, which is the default maximum residue level for food intended for infants and young children, the application of the fungicides under study should be carried out 2 or 3 months before harvest at the lower (1.0 L/ha) and the higher (1.5 L/ha) recommended dose, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.
Vayssade, Chloé; de Fazio, Céline; Quaglietti, Bastien; Auguste, Alexandra; Ris, Nicolas; Fauvergue, Xavier
Inbreeding and inbreeding depression are key processes in small or isolated populations and are therefore central concerns for the management of threatened or (re)introduced organisms. Haplodiploid species of the order Hymenoptera have a particular status with regard to inbreeding depression. Although recessive deleterious alleles that are expressed in males should be purged, an alternative form of inbreeding depression exists in species with single-locus complementary sex determination (sl-CSD). Under sl-CSD, genetically-related parents have a high probability of producing sterile sons instead of fertile daughters. In this article, we study inbreeding depression in Venturia canescens (Hymenoptera: Ichneumonidae), a parasitoid wasp with sl-CSD. We used a crossing design to manipulate relatedness according to three levels: within-family, between-family and between-population. For each level, several fitness components were measured on parents and female offspring. We found a 20% reduction in egg load at emergence for inbred crosses. Inbred crosses also yielded a higher proportion of males, as expected in a species with sl-CSD. Mating probability, presence of daughters among offspring, body size, symmetry and longevity were unaffected by inbreeding.
Ladu, G; Pani, G; Venditti, T; Dore, A; Molinu, M G; D'Hallewin, G
Natural resistance against Venturia pirina and Botrytis cinerea was investigated within the Sardinian pears germplasm. The natural occurrence of V. pirina was monitored at the orchard level for 5 years, while resistance against B. cinerea was evaluated by a bioassay using methanolic extracts of the fruit rind or by artificially inoculation. Methanolic extracts of the leaves were employed for the Cladosporium bioassay on TLC plates. Among the accessions, 8 resulted sensitive to V. pirina, vegetation and fruit are severely affected every year. Seven showed an intermediate behaviour and the sole vegetation was affected slightly in two out of the 5 years. Two inhibition spots, in the methanolic extract of the leaves, were clearly evidenced in 55 accessions and a positive correlation was found between the presence of these antifungal compounds in the leaves and the resistance to V. pirina in the field. The artificial inoculation of fruit with B. cinerea evidenced a great variability in resistance, with about 12 accessions that could be considered having a good resistance. The fruit rind methanolic extracts evidenced several inhibition spots in most accessions, but no correlation could be found with fruit resistance to B. cinerea. In addition, the activity of the polygalacturonase inhibiting protein (PGIP), determined with an agarose diffusion bioassay, indicate a positive correlation between the PGIP activity evidenced in the core tissue and the infection degree by B. cinerea.
Ogawa, Roann E.; Carr, John F.
A series of experiments on heterocyst production in Anabaena variabilis provides some strong indirect evidence for the role of heterocysts in nitrogen fixation. Of the algae tested (Anabaena variabilis, A. inaequalis, A. cylindrica, A. flos-aquae, Tolypothrix distorta, Gloeotrichia echinulata, Aphanizomenon flos-aquae, Oscillatoria sp., and Microcystis aeruginosa), only those with heterocysts grew in a nitrate-free medium. Growth in the nitrate-free medium was accompanied by an increase in heterocysts. Heterocyst formation in A. variabilis was evident 24 hr after transfer from a nitrate-containing to a nitrate-free medium. The number of heterocysts was altered by changes in the nitrogen source. Numbers were lowest when NH4-N was used as a nitrogen source and highest when nitrogen (N2-N) was derived from the atmosphere. Heterocyst numbers could also be regulated by controlling the concentration of NO3-N in the medium. Heterocyst production depended on the absence of combined nitrogen and the presence of phosphate. Data are presented on the occurrence of blue-green algae (with heterocysts) in Lake Erie and the environmental conditions apparently necessary for them to become dominant.
Isupov, M N; Dalby, A R; Brindley, A A; Izumi, Y; Tanabe, T; Murshudov, G N; Littlechild, J A
The three-dimensional structure of the vanadium bromoperoxidase protein from the marine red macroalgae Corallina officinalis has been determined by single isomorphous replacement at 2.3 A resolution. The enzyme subunit is made up of 595 amino acid residues folded into a single alpha+beta domain. There are 12 bromoperoxidase subunits, arranged with 23-point group symmetry. A cavity is formed by the N terminus of each subunit in the centre of the dodecamer. The subunit fold and dimer organisation of the Cor. officinalis vanadium bromoperoxidase are similar to those of the dimeric enzyme from the brown algae Ascophyllum nodosum, with which it shares 33 % sequence identity. The different oligomeric state of the two algal enzymes seems to reflect separate mechanisms of adaptation to harsh environmental conditions and/or to chemically active substrates and products. The residues involved in the vanadate binding are conserved between the two algal bromoperoxidases and the vanadium chloroperoxidase from the fungus Curvularia inaequalis. However, most of the other residues forming the active-site cavity are different in the three enzymes, which reflects differences in the substrate specificity and stereoselectivity of the reaction. A dimer of the Cor. officinalis enzyme partially superimposes with the two-domain monomer of the fungal enzyme. Copyright 2000 Academic Press.
Sorokina, Vera S; Pont, Adrian C
A key is provided to the 26 species of the genus Drymeia Meigen, 1826 known from Russia and four additional species that may be found in Russia (D. brumalis (Rondani, 1866), D. cantabrigensis (Huckett, 1965), D. gymnophthalma (Hennig, 1963), D. similis (Malloch, 1918)). The key includes the 10 new species here described from the mountains of South Siberia (D. acrostichalis sp. nov., D. aristata sp. nov., D. cilitarsis sp. nov., D. glabra sp. nov., D. grandis sp. nov., D. grisea sp. nov., D. longiseta sp. nov., D. phaonina sp. nov., D. puchokana sp. nov., D. triseta sp. nov.,) and other two new species from the Russian Arctic (D. cristata sp. nov., D. taymirensis sp. nov.). Five species (D. fasciculata (Stein, 1916), D. firthiana (Huckett, 1965), D. groenlandica (Lundbeck, 1901), D. quadrisetosa (Malloch, 1919), D. neoborealis (Snyder, 1949)) are newly recorded from Russia. Three new synonymies are proposed: D. pribilofensis (Malloch, 1921) (syn: D. inaequalis (Malloch, 1922)), D. setibasis (Huckett, 1965) (syn: D. gymnophthalma sibirica (Lavčiev, 1971, unavailable junior secondary homonym) and D. quadrisetosa (Malloch, 1919) (syn: D. amurensis (Lavčiev, 1971)). The male terminalia and the female ovipositors of the new species are illustrated. New faunistic data are given for some previously described species of Russian Drymeia.
Maria Helena M. Galileo
Full Text Available New species are described: Tessaropa elongata sp. nov. from Brazil (Rondônia has long elytra, a character that distinguishes it from the remaining species with short elytra; Hexoplon immaculatum sp. nov. from Ecuador (Pichincha is characterized by the red-orange general color and black legs. Eburodacrys inaequalis sp. nov. from Bolivia (Santa Cruz has elytral apices and same-color femora that cause it to be similar to E. ayri Martins & Galileo, 2006 and E. silviamariae Martins & Galileo, 2006, yet it differs from either species in the black lateral spines and dorsal tubercles of pronotum and the elongate eburneuos maculae of the elytra. Coleomethia bezarki sp. nov. (Costa Rica, Guanacaste differs from C. australis Hovore, 1987 by male pronotum without rugosities, peduculate metafemora and metatibiae entirely pubescent. Bisaltes (B. petilus sp. nov. (Costa Rica, Guanacaste, Alajuela is separated from B. (B.buquetii Thomson, 1868 and B. (B. fuchsi Breuning, 1971 by the more slender body appearance, the absence of dark belts on pronotum, and the absence of circular macula in the anterior third of elytra. Notes and new records are provided for: Tetraibion concolor Martins, 2006 (Bolivia: La Paz; Gnomidolon ornaticolle Martins, 1960 (Panama: Colón; Mephritus apicatus (Linsley, 1935 (Brazil: Rondônia.
Olaf H. H. Mielke
Full Text Available Comments on the systematic position and synonymy of the Hesperiidae described by J. Roeber are presented. The Syn. n. are the following: Jemadia gigantea Roeber, 1925 of Nosphistia zonara (Hewitson, 1866, Pyrrhopyga josepha Ploetz, 1879 of Hegesippe luteizona (Mabille, 1877, Phocides palaemonides Roeber, 1925 of Phocides palemon palemon (Cramer, 1777, Phocides xenocrates Bell, 1935 of Phocides vulcanides Roeber, 1925, Phocides parvus Roeber, 1925 of Phocides pialia pialia (Hewitson, 1857, Thymele aulicusi Roeber, 1925 of Astraptes enotrus (Cramer, 1781, Pythonides zonula Mabille, 1889 of Paches loxus loxus (Westwood, 1852, Thespieus chlorocephala Roeber, 1925 of Thespieus lutetia (Hewitson, 1866, Xeniades cecropteroides Roeber, 1925 of Niconiades caeso (Mabille, 1891 and Thracides nanea chiricana Roeber, 1925 of Thracides nanea nanea (Hewtson, 1867. Metron leucogaster leucomelas (Roeber, 1925 is a Comb. n. and a Stat. n. for Zenis leucomelas. Lectotypes are designated for the following species or subspecies: Mimoniades hemitaenia Roeber, 1925, Mimoniades inaequalis Roeber, 1925, Amenis similis Roeber, 1925, Mysoria erythrostigma Roeber, Myscelus nobilis meridionalis Roeber, 1925, Phocides iocularis Roeber, 1925, Phocides parvus Roeber, 1925, Polygonus amyntas pallida Roeber, 1925, Thymele albifasciatus Roeber, 1925, Thymele subfasciatus Roeber, 1925, Thymele aulicus Roeber, 1925, Phyrrhocalles kruegeri Roeber, 1925, Vettius phyllides Roeber, 1925 and Xeniades cecropteroides Roeber, 1925.
Abdel-Dayem, Mahmoud S; Fad, Hassan H; El-Torkey, Ashraf M; Elgharbawy, Ali A; Aldryhim, Yousif N; Kondratieff, Boris C; Ansi, Amin N Al; Aldhafer, Hathal M
This study was conducted as a part of a comprehensive baseline survey of insect biodiversity of Rawdhat Khorim National Park (RKNP), Central Kingdom of Saudi Arabia (KSA). During this study a total of 262 Coleoptera species belong to 182 genera in 35 families were identified, of which 247 are named at a species level. Fifteen species (6.0%) are apparently endemic to KSA. Thirty-eight species are new to the known beetle fauna of KSA, including 25 species reported from the Arabian Peninsula for the first time. The families Tenebrionidae (45 species), Scarabaeidae (34 species), and Carabidae (27 species) were the most species rich families. About 37% of the beetle abundance was represented by species of Scarabaeidae, especially Aphodius ictericus ghardimaouensis Balthasar. Karumia inaequalis Pic (Dascillidae) was also an abundant species. Approximately 43.5% of beetle species collected during this study are considered very rare taxa in RKNP. The RKNP beetle fauna shows more affinity to Sahro-Arabian (36.4%), Afrotropical-Sahro-Arabian (17.4%) and Palaearctic-Sahro-Arabian (10.5%). Twenty-three species (9.3%) are considered cosmopolitan or subcosmopolitan. The data on month of collection, method of collection, and abundance status within RKNP, together with the distribution within KSA and the general distribution (zoogeography) of each species are presented.
Gyoung Hee Kim
Full Text Available Scabs caused by Venturia carpophila greatly reduce the quality of the fruits of the Japanese apricot (Prunus mume when the disease is not properly managed. The disease produces a superficial blemish that is unlikely to affect the overall yield of processed fruit, but reduce the value of fruit intended for the fresh market. Incidence rates of scab at sprayed and unsprayed orchards range from 0% to 21.5% and from 30.2% to 100%, respectively, in the major cultivation regions of Jeonnam Province during the growing season of 2009. The trends in disease progress were quite similar, regardless of regions, and cultivar Namgo was relatively less damaged by scab compared to cultivar Cheonmae among the tested Japanese apricot cultivars. The fruits on branches 1.5 m above the infected Japanese apricot trees and the stem-end parts of the infected fruits were more severely damaged by scabs, possibly because of rain and run-off facilitate dissemination of conidia of V. carpophila and subsequent infection of the fruits or branches. The conidia of V. carpophila were dispersed from March 24 to April 26 in 2010, and more conidia were dispersed from 2-year-old branches than 1-year-old branches. Since the control efficacies were higher than 90% after more than two applications of Trifloxystrobin WG at 10-day-intervals from mid April, it is that effective fungicides be applied at least two times at 10-day-intervals from the middle of April to manage scabs of Japanese apricot in orchards.
Kim, Gyoung Hee; Jo, Kyoung Youn; Shin, Jong Sup; Shin, Gil Ho; Koh, Young Jin
Scabs caused by Venturia carpophila greatly reduce the quality of the fruits of the Japanese apricot (Prunus mume) when the disease is not properly managed. The disease produces a superficial blemish that is unlikely to affect the overall yield of processed fruit, but reduce the value of fruit intended for the fresh market. Incidence rates of scab at sprayed and unsprayed orchards range from 0% to 21.5% and from 30.2% to 100%, respectively, in the major cultivation regions of Jeonnam Province during the growing season of 2009. The trends in disease progress were quite similar, regardless of regions, and cultivar Namgo was relatively less damaged by scab compared to cultivar Cheonmae among the tested Japanese apricot cultivars. The fruits on branches 1.5 m above the infected Japanese apricot trees and the stem-end parts of the infected fruits were more severely damaged by scabs, possibly because of rain and run-off facilitate dissemination of conidia of V. carpophila and subsequent infection of the fruits or branches. The conidia of V. carpophila were dispersed from March 24 to April 26 in 2010, and more conidia were dispersed from 2-year-old branches than 1-year-old branches. Since the control efficacies were higher than 90% after more than two applications of Trifloxystrobin WG at 10-day-intervals from mid April, it is that effective fungicides be applied at least two times at 10-day-intervals from the middle of April to manage scabs of Japanese apricot in orchards.
The Vanadium Iodoperoxidase from the marine flavobacteriaceae species Zobellia galactanivorans reveals novel molecular and evolutionary features of halide specificity in the vanadium haloperoxidase enzyme family.
Fournier, Jean-Baptiste; Rebuffet, Etienne; Delage, Ludovic; Grijol, Romain; Meslet-Cladière, Laurence; Rzonca, Justyna; Potin, Philippe; Michel, Gurvan; Czjzek, Mirjam; Leblanc, Catherine
Vanadium haloperoxidases (VHPO) are key enzymes that oxidize halides and are involved in the biosynthesis of organo-halogens. Until now, only chloroperoxidases (VCPO) and bromoperoxidases (VBPO) have been characterized structurally, mainly from eukaryotic species. Three putative VHPO genes were predicted in the genome of the flavobacterium Zobellia galactanivorans, a marine bacterium associated with macroalgae. In a phylogenetic analysis, these putative bacterial VHPO were closely related to other VHPO from diverse bacterial phyla but clustered independently from eukaryotic algal VBPO and fungal VCPO. Two of these bacterial VHPO, heterogeneously produced in Escherichia coli, were found to be strictly specific for iodide oxidation. The crystal structure of one of these vanadium-dependent iodoperoxidases, Zg-VIPO1, was solved by multiwavelength anomalous diffraction at 1.8 Å, revealing a monomeric structure mainly folded into α-helices. This three-dimensional structure is relatively similar to those of VCPO of the fungus Curvularia inaequalis and of Streptomyces sp. and is superimposable onto the dimeric structure of algal VBPO. Surprisingly, the vanadate binding site of Zg-VIPO1 is strictly conserved with the fungal VCPO active site. Using site-directed mutagenesis, we showed that specific amino acids and the associated hydrogen bonding network around the vanadate center are essential for the catalytic properties and also the iodide specificity of Zg-VIPO1. Altogether, phylogeny and structure-function data support the finding that iodoperoxidase activities evolved independently in bacterial and algal lineages, and this sheds light on the evolution of the VHPO enzyme family. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
López-Uribe, Margarita M; Morreale, Stephen J; Santiago, Christine K; Danforth, Bryan N
Bees are the primary pollinators of flowering plants in almost all ecosystems. Worldwide declines in bee populations have raised awareness about the importance of their ecological role in maintaining ecosystem functioning. The naturally strong philopatric behavior that some bee species show can be detrimental to population viability through increased probability of inbreeding. Furthermore, bee populations found in human-altered landscapes, such as urban areas, can experience lower levels of gene flow and effective population sizes, increasing potential for inbreeding depression in wild bee populations. In this study, we investigated the fine-scale population structure of the solitary bee Colletes inaequalis in an urbanized landscape. First, we developed a predictive spatial model to detect suitable nesting habitat for this ground nesting bee and to inform our field search for nests. We genotyped 18 microsatellites in 548 female individuals collected from nest aggregations throughout the study area. Genetic relatedness estimates revealed that genetic similarity among individuals was slightly greater within nest aggregations than among randomly chosen individuals. However, genetic structure among nest aggregations was low (Nei's GST = 0.011). Reconstruction of parental genotypes revealed greater genetic relatedness among females than among males within nest aggregations, suggesting male-mediated dispersal as a potentially important mechanism of population connectivity and inbreeding avoidance. Size of nesting patch was positively correlated with effective population size, but not with other estimators of genetic diversity. We detected a positive trend between geographic distance and genetic differentiation between nest aggregations. Our landscape genetic models suggest that increased urbanization is likely associated with higher levels of inbreeding. Overall, these findings emphasize the importance of density and distribution of suitable nesting patches for enhancing
Full Text Available Cucumber plants (Cucumis sativus L. that includes or creeping vines and is one type of vegetable-fruit of the gourd family labuan (Cucurbitaceae that has been popular throughout the world and favored from Asia. Cucumber cultivation in Indonesia, found almost in every region, ranging from lowland to highland hot climate (tropical and moderate. One animal that has an abundant amount in cucumber plants are insects. This study aims to know the different types of species that exist on the Order Coleoptera cucumber farm in the village of Tirta Mulya District of makarti Jaya Banyuasin II and determine the role of the Order Coleoptera insects on cucumber plantations in the village of Tirta Mulya District of makarti Jaya Banyuasin II. This is a qualitative study conducted in October-November 2014 held in Cucumber Plants in the village of Tirta Mulya District of makarti Jaya Banyuasin II. Catching insects done using transect method and pitfall traps such as sweeping the net, pit fall traps and light traps, results in identification in the laboratory penelitanya UIN Raden Fatah Palembang. The results of this study indicate that insects are caught in a cucumber plantation obtained as many as 113 individual 3 families and 7 species. Insects which dominates in the village of Tirta Mulya District of makarti Jaya Banyuasin II is Cocinella repanda, Curinus coeruleus, Coelophora inaequalis, and Aulacophora similis, and insects that have the fewest number is Micraspis discolor, Micraspis vincta and Oryctes rhinoceros. The role of the Order Coleoptera Insects in general predators of the family Coccinellidae to eradicate mites while the family Chrysomelidae Scarabacidae and are pests that attack on cucumber plants that can cause death.