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1.
BACKGROUND: Grey mould caused by the fungus Botrytis cinerea Pers. ex Fr. is one of the major diseases in grapes. The use of fungicides is a simple strategy to protect grapes against B. cinerea disease. However, phenotypes exhibiting resistance to fungicides have been detected in B. cinerea populations. The variation of fungicide‐resistant B. cinerea isolates renders B. cinerea disease control difficult in grapevine fields. RESULTS: The authors have developed a nested polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) method to detect fungicide‐resistant B. cinerea isolates at an early growth stage of grapes in grapevine fields. The nested PCR‐RFLP method was carried out to detect benzimidazole‐, phenylcarbamate‐ and/or dicarboximide‐resistant B. cinerea isolates from grape berries and leaves at Eichorn–Lorenz growth stage 25 to 29. This method successfully detected fungicide‐resistant B. cinerea isolates at an early growth stage of grapes. In addition, only 8 h was required from tissue sampling to phenotyping of fungicide resistance of the isolates. CONCLUSION: It is proposed that the early diagnosis of fungicide‐resistant B. cinerea isolates would contribute to further improvement of integrated pest management against B. cinerea in grapevine fields, and that the nested PCR‐RFLP method is a high‐speed, sensitive and reliable tool for this purpose. Copyright © 2008 Society of Chemical Industry  相似文献   

2.
Tomato and strawberry are the most important protected crops in Lebanon and are seriously affected by grey mould disease, caused by Botrytis cinerea. In the present study, the fungicide sensitivity assays revealed medium to high frequencies of B. cinerea isolates resistant to benzimidazoles, dicarboximides, and anilinopyrimidines on tomato and strawberry. Fludioxonil- and boscalid-resistant mutants were uncommonly found at generally low frequency on both crops. Resistance to fenhexamid was detected in only one site on tomato but in most sites on strawberry with high frequencies, and the occurrence of resistance to QoI fungicides was ascertained on both crops. The majority of the tested isolates (>90%) exhibited multiple fungicide resistance, and isolates resistant to the seven antibotrydial fungicide classes were detected on strawberry in three locations. A high level of resistance was shown by B. cinerea mutants resistant to boscalid, fenhexamid, and QoI fungicides, while two levels of moderate and high resistance to anilinopyrimidines were identified. Genetic analysis revealed point mutations in the target genes commonly associated with resistance in B. cinerea isolates, with all mutants resistant to dicarboximides, fenhexamid, boscalid, and QoI fungicides carrying single-nucleotide polymorphims in BcOS1 (I365S/N, Q369P, and N373S), Erg27 (F412V/I), SdhB (H272R/Y), and cytb (G143A) genes, respectively. The general incorrect use of fungicides has caused the development and spread of fungicide resistance as a widespread phenomenon on protected tomato and strawberry in Lebanon. The implementation of appropriate antiresistance strategies is highly recommended.  相似文献   

3.
Grey mould, caused by Botrytis cinerea, is a disease severely affecting grape production in northern Italy. However, little information is available on the variability of B. cinerea populations associated with grapevine. The mode of reproduction, sensitivity to fungicides, and for the first time in Italy, the genetic structure of B. cinerea populations isolated from grapevine in a northern Italian region are reported. Botrytis cinerea isolates (317) were completely genotyped for six microsatellite loci and characterized for the presence of the transposable elements Boty and Flipper, for the mating type and for resistance to cyprodinil, fludioxonil, boscalid and fenhexamid. All the isolates were found to belong to B. cinerea Group II, indicating the absence of B. pseudocinerea in the investigated areas. The populations possess a high genotypic diversity, different frequencies of transposable elements and a mixed mode of reproduction. At a regional level, B. cinerea populations belong to a large and interconnected pathogen population that includes the major grape‐growing districts. The populations were generally sensitive to fungicides, with a low proportion (8%) of isolates resistant to cyprodinil, fludioxonil and boscalid. A small genetic distance was found between B. cinerea populations. However, the populations geographically isolated from the others by a mountain range showed a small but statistically significant genetic differentiation and a different pattern of fungicide resistance. The results show that northern Italian B. cinerea populations possess a high evolutionary potential and adaptive capacity.  相似文献   

4.
BACKGROUND: Bromus rigidus is a common weed species that has increased in cropping fields owing to limited control options. During a random field survey in Western Australia, six B. rigidus populations that had survived in‐crop weed control programmes were collected. The study aimed to determine the resistance profile of these six populations. RESULTS: Based on dose–response studies, all six B. rigidus populations had a low‐level resistance to sulfosulfuron and sulfometuron (both sulfonylurea herbicides) while remaining susceptible to herbicides with other modes of action. ALS in vitro activity assays revealed no differences in enzyme sensitivity between susceptible and resistant populations, while the use of malathion (a cytochrome P450 inhibitor) in combination with sulfosulfuron caused the resistant populations to behave like the susceptible population. CONCLUSION: This study established that these six B. rigidus populations have a low‐level resistance to the ALS‐inhibiting sulfonylurea herbicides, but are able to be controlled by other herbicide modes of action. The low‐level, malathion‐reversible resistance, together with a sensitive ALS, strongly suggest that a non‐target‐site enhanced metabolism is the mechanism of resistance. Copyright © 2012 Society of Chemical Industry  相似文献   

5.
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6.
A novel, high‐resolution melting (HRM) analysis was developed to detect single nucleotide polymorphisms (SNPs) associated with resistance to fenhexamid (hydroxyanilides) and boscalid (succinate dehydrogenase inhibitors) in Botrytis cinerea isolates. Thirty‐six single‐spore isolates arising from 13 phenotypes were selected and tested for fungicide sensitivity. Germ tube elongation assays showed two distinct sensitivity levels for each fungicide. Sequencing revealed that resistance to fenhexamid was due to a nucleotide change in the erg27 gene, resulting in an amino acid replacement of phenylalanine (F) with serine (S) or valine (V) at position 412 of the protein, whereas in isolates resistant to boscalid, a nucleotide change in the sdhB gene resulted in the replacement of histidine (H) with arginine (R) or tyrosine (Y) at position 272 of the respective protein. In each case, melting curve analysis generated three distinct profiles corresponding to the presence of each nucleotide in the targeted areas. HRM analysis successfully detected and differentiated the substitutions associated with resistance to both fungicides. In vitro bioassays, direct sequencing and high‐resolution melting analysis showed a 100% correlation with detection of resistance. The results demonstrate the utility of HRM analysis as a potential molecular tool for routine detection of fungicide resistance using known polymorphic genes of B. cinerea populations.  相似文献   

7.
We assessed the contributions of target site‐ and non‐target site‐based resistance to herbicides inhibiting acetyl‐coenzyme A carboxylase (ACC) in Alopecurus myosuroides (black grass). A total of 243 A. myosuroides populations collected across France were analysed using herbicide sensitivity bioassay (24 300 seedlings analysed) and ACC genotyping (13 188 seedlings analysed). Seedlings resistant to at least one ACC‐inhibiting herbicide were detected in 99.2% of the populations. Mutant, resistant ACC allele(s) were detected in 56.8% of the populations. Among the five resistant ACC alleles known in A. myosuroides, alleles containing an isoleucine‐to‐leucine substitution at codon 1781 were predominant (59.5% of the plants containing resistant ACC alleles). Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 75% of the plants resistant to ACC‐inhibiting herbicides in France would be resistant via increased herbicide metabolism. Analysis of herbicide application records suggested that in 15.9% of the populations studied, metabolism‐based resistance to ACC‐inhibiting herbicides was mostly selected for by herbicides with other modes of action. Our study revealed the importance of non‐target site‐based resistance in A. myosuroides. Using herbicides with alternative modes of action to control populations resistant to ACC‐inhibiting herbicides, the recommended management approach, may thus be jeopardised by the widespread occurrence of metabolism‐based resistance mechanisms conferring broad‐spectrum cross‐resistance.  相似文献   

8.
Botrytis cinerea is a complex species prone to fungicide resistance and characterized by enormous genetic diversity. During 2013, 220 B. cinerea isolates causing gray mold were collected from greenhouse-grown crops in the regions of Ammochostos, Larnaca, and Limassol (Cyprus). Sensitivities of the sampled populations to seven botryticides with different modes of action were screened in vitro. The results of this in vitro screening highlighted the widespread phenomenon of fungicide resistance in greenhouses, since only 8.6 % of the isolates were sensitive to all botryticides. Resistance to thiophanate-methyl was the most prevalent, with frequencies ranging from 53.8 % to 80 %. Similarly, high resistance frequencies were observed for pyraclostrobin (27.1 to 78.9 %) and boscalid (28.2 to 66.2 %). Multiple fungicide resistant phenotypes were predominant, covering 67.3 % of the population, with frequencies of 80.0, 37.5, 53.8, 83.1, and 60.2 % in cucumber, eggplant, green bean, strawberry, and tomato, respectively. No fludioxonil-resistant isolates were observed. Botrytis cinerea and Botrytis group S genotypes comprised the gray mold population. B. cinerea was predominant within cucumber, eggplant and strawberry, whereas both genotypes were in equilibrium in green bean and tomato. However, Botrytis group S was found in all hosts. B. cinerea was the most prevalent in the majority of fungicide resistance phenotypes from strawberry, while genotype distributions within tomato were generally more balanced. B. pseudocinerea was not detected in the sampled population. Overall, frequency of the mating type allele MAT1–1 was higher to MAT1–2, underlying their unequal distribution in the population. However, cases of 1:1 distribution were apparent within particular subpopulations, suggesting that mating in the field cannot be excluded.  相似文献   

9.
Root exudates secreted from plants can modify rhizosphere microbiota by enhancing or inhibiting the growth of biological control agents (BCAs) and/or pathogens. Similarly, microorganisms can modify the secretion of plant root exudates. The aim of this study was to analyse the effect of a Botrytis cinerea leaf infection on the secretion of tomato root exudates and on the populations of the BCA Trichoderma asperellum strain T34 (T34). This study found that the secretion pattern of root exudates in tomato plants was influenced by B. cinerea infection in plant leaves. An increase in the levels of gluconic acid was observed, while levels of sucrose and inositol decreased. A decrease in the severity of B. cinerea by the induction of systemic resistance triggered by T34 was also observed. Tomato plants infected with B. cinerea maintained the populations of T34 in the roots, while populations of T34 decreased in plants not inoculated with the pathogen. Samples exposed to media containing gluconic acid (as the only carbon source or at the same concentration found in roots exudates) saw an increase in the in vitro growth of T34 compared to media without gluconic acid. In conclusion, a change in the secretion pattern of root exudates caused by B. cinerea, together with the enhanced growth of T34 in the presence of gluconic acid, indicates the existence of leaf to root communication. The result of this is enhanced populations of T34, and in turn induced disease resistance and a consequential reduction in disease severity.  相似文献   

10.
Serious fungicide resistance problems have been encountered in several major vegetable pathogens in glasshouses in Crete. Botrytis cinerea populations are now widely resistant to either or both benzimidazoles and dicarboximides. Pseudoperonospora cubensis very rapidly became resistant to metalaxyl, with cross resistance to other acylalanines. Didymella bryoniae has shown some benzimidazolc resistance. Sphaerotheca fuliginea, against which a great diversity of fungicides is used, has mostly not given problems. However, strains with resistance to benomyl, triforine and ditalimfos have been found in experimental plots. Ways of managing resistance in Crete are discussed.  相似文献   

11.
Control of grey mould, caused by Botrytis spp., is a major challenge in open field strawberry production. Botrytis was isolated from plant parts collected from 19 perennial strawberry fields with suspected fungicide resistance in the Agder region of Norway in 2016. Resistance to boscalid, pyraclostrobin and fenhexamid was high and found in 89.1%, 86.0% and 65.4% of conidia samples, respectively. Multiple fungicide resistance was common; 69.6% of conidia samples exhibited resistance to three or more fungicides. Botrytis group S and B. cinerea sensu stricto isolates were obtained from 19 and 16 fields, respectively. The sdhB, cytb, erg27 and mrr1 genes of a selection of isolates were examined for the presence of mutations known to confer fungicide resistance to boscalid, pyraclostrobin, fenhexamid and pyrimethanil plus fludioxonil, respectively. Allele-specific PCR assays were developed for efficient detection of resistance-conferring mutations in cytb. Among B. cinerea isolates, 84.7%, 86.3% and 61.3% had resistance-conferring mutations in sdhB, cytb and erg27, respectively. A triplet deletion in mrr1, resulting in ΔL497, commonly associated with the multidrug resistance phenotype MDR1h, was detected in 29.2% of Botrytis group S isolates. High frequencies of resistance to several fungicides were also detected in Botrytis from both imported and domestically produced strawberry transplants. Fungicide resistance frequencies were not different among fields grouped by level of grey mould problem assessed by growers, indicating factors other than fungicide resistance contributed to control failure, a fact that has important implications for future management of grey mould.  相似文献   

12.
BACKGROUND: The neonicotinoid class of insecticides is a key component of pest management strategies used by stone fruit producers in Europe. Neonicotinoids are currently one of the most important tools for control of the peach‐potato aphid (Myzus persicae). Overreliance on neonicotinoids has led to the development of resistance through a combination of metabolic and target‐site resistance mechanisms in individual aphids. A resistance monitoring project was conducted by Syngenta in 2010 to determine the resistance status of M. persicae populations collected from France and Spain, and to determine the frequency of the target‐site mutation in those populations. RESULTS: Resistance monitoring suggests that resistance to neonicotinoids is relatively widespread in populations of M. persicae collected from peach orchards in the Languedoc‐Roussillon, Provence‐Alpes‐Cote d'Azur and Rhone‐Alpes regions of France, and resistance can be associated with the frequency of the target‐site mutation (R81T). The R81T mutation in its heterozygous form is also present in Spanish populations and is associated with neonicotinoid resistance. CONCLUSION: The widespread nature of neonicotinoid resistance in southern France and the potential for resistance development in northern Spain highlight the need for a coordinated management strategy employing insecticides with different modes of action to reduce the selection pressure with neonicotinoids. Copyright © 2011 Society of Chemical Industry  相似文献   

13.
Chitosan inhibited growth of Botrytis cinerea in liquid culture and suppressed grey mould on detached grapevine leaves and bunch rot in commercial winegrapes. Germination of B. cinerea was completely inhibited in malt extract broth containing chitosan at concentrations greater than 0·125 g L?1. However, treated conidia were able to infect detached Chardonnay leaves and pathogenicity was not affected, even after incubation for 24 h in chitosan at 10 g L?1. When added after conidial germination, chitosan inhibited B. cinerea growth and induced morphological changes suggestive of possible curative activity. The effective concentration of chitosan that reduced mycelial growth by 50% (EC50) was 0·06 g L?1. As a foliar treatment, chitosan protected detached Chardonnay leaves against B. cinerea and reduced lesion diameter by up to 85% compared with untreated controls. Peroxidase and phenylalanine ammonia‐lyase activities were also induced in treated leaves. In vineyard studies, Chardonnay winegrapes exhibited 7·4% botrytis bunch rot severity at harvest in 2007 after treatment with an integrated programme that included chitosan sprays from bunch closure until 2 weeks preharvest, compared with 15·5% in untreated controls and 5·9% with fungicide treatment. In the following season, botrytis bunch rot severity was 44% in untreated Chardonnay at harvest and the integrated programme (21%) was less effective than fungicides (13·8%). However, in Sauvignon blanc winegrapes, the integrated and the fungicide programme each reduced botrytis bunch rot severity to 4% and were significantly different from the untreated control (11·5%). This study provides evidence that suppression of botrytis in winegrapes by chitosan involves direct and indirect modes of action.  相似文献   

14.

BACKGROUND

Fenpicoxamid is a new fungicide for control of Zymoseptoria tritici, and is a derivative of the natural product UK‐2A. Its mode of action and target site interactions have been investigated.

RESULTS

UK‐2A strongly inhibited cytochrome c reductase, whereas fenpicoxamid was much less active, consistent with UK‐2A being the fungicidally active species generated from fenpicoxamid by metabolism. Both compounds caused rapid loss of mitochondrial membrane potential in Z. tritici spores. In Saccharomyces cerevisiae, amino acid substitutions N31K, G37C and L198F at the Qi quinone binding site of cytochrome b reduced sensitivity to fenpicoxamid, UK‐2A and antimycin A. Activity of fenpicoxamid was not reduced by the G143A exchange responsible for strobilurin resistance. A docking pose for UK‐2A at the Qi site overlaid that of antimycin A. Activity towards Botrytis cinerea was potentiated by salicylhydroxamic acid, showing an ability of alternative respiration to mitigate activity. Fungitoxicity assays against Z. tritici field isolates showed no cross‐resistance to strobilurin, azole or benzimidazole fungicides.

CONCLUSION

Fenpicoxamid is a Qi inhibitor fungicide that provides a new mode of action for Z. tritici control. Mutational and modeling studies suggest that the active species UK‐2A binds at the Qi site in a similar, but not identical, fashion to antimycin A. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

15.
Fungicides inhibiting sterol biosynthesis are frequently used for powdery mildew control and can be subdivided into sterol demethylation inhibitors (DMIs) and morpholines with different modes of action. Whereas fungicide resistance to DMIs (Rdmi) and morpholines (Rmor) has been continuously monitored, there are no data available on the combination of Rdmi and Rmor, which led us to ask whether multiple resistance to triadimenol (Rtria), representing DMIs and to fenpropimorph (Rfen), representing the morpholines, evolved in France from 1993 to 1996. The method used allowed testing of both chemicals simultaneously, with the same inoculum. In 1993, the resistance factor of the mean (RFM) of the French wheat mildew population was 9·59 for Rtria and 5·11 for Rfen. Resistance increased, leading to RFMs of close to 14 for Rtria and 8 for Rfen at the end of the study. From the analysis of single colony isolates (SCI) that are genetically uniform, the presence of multiple resistance and its increase were evident and in line with the results of bulk isolates. Covariance of resistance to both chemicals was close to one. In contrast to the increase of Rfen, the use of morpholines decreased. These effects are supposed to result from multiple selection due to the use of mixtures of DMIs and morpholines that have been favoured in recent years. Fungicide sensitivity is, in general, not normally but lognormally distributed in a population. A new way to evaluate and describe lognormal data is presented. It is easy and convenient to use and provides solutions for current problems in the literature with lognormal distributions. Multiple resistance, its evolution and persistance are discussed in relation to fungicide use and to implications for anti-resistance strategies. © 1998 Society of Chemical Industry  相似文献   

16.
The severity of disease caused byBotrytis cinerea in strawberries is very high and chemical control is common practice; low residue levels of chemical products are required. Thus, it is important to be aware of the development of fungicide resistance in order to choose the best strategies of chemical control. In the present study we evaluated the response of 36B. cinerea isolates against eight different fungicides. The isolates were sampled twice, at the beginning and the end of the season, in 11 commercial strawberry fields located in the area of Huelva (Spain). In addition, two reference isolates, SAS56 and SAS405, were evaluated. The proportion of isolates resistant to benomyl was very high (86%). Resistance to dicarboximides was detected in 44% of the isolates and resistance to pyrimethanil in 25% of the isolates. Different degrees of sensitivity to captan and dichlofluanid were recorded. No resistance was found to diethofencarb plus carbendazim. http://www.phytoparasitica.org posting Sept. 18, 2002.  相似文献   

17.
BACKGROUND: Botrytis cinerea Pers.: Fr. is a high‐risk pathogen for fungicide resistance development that has caused resistance problems on many crops throughout the world. This study investigated the fungicide sensitivity profile of isolates from kiwifruits originating from three Greek locations with different fungicide use histories. Sensitivity was measured by in vitro fungitoxicity tests on artificial nutrient media. RESULTS: Seventy‐six single‐spore isolates were tested for sensitivity to the SDHI fungicide boscalid, the QoI pyraclostrobin, the anilinopyrimidine cyprodinil, the hydroxyanilide fenhexamid, the phenylpyrrole fludioxonil, the dicarboxamide iprodione and the benzimidazole carbendazim. All isolates from Thessaloniki showed resistance to both boscalid and pyraclostrobin, while in the other two locations the fungal population was sensitive to these two fungicides. Sensitive isolates showed EC50 values to boscalid and pyraclostrobin ranging from 0.9 to 5.2 and from 0.04 to 0.14 mg L?1 respectively, while the resistant isolates showed EC50 values higher than 50 mg L?1 for boscalid and from 16 to > 50 mg L?1 for pyraclostrobin. All QoI‐resistant isolates carried the G143A mutation in cytb. Sensitivity determinations to the remaining fungicides revealed in total eight resistance phenotypes. No isolates were resistant to the fungicides fenhexamid and fludioxonil. CONCLUSION: This is the first report of B. cinerea field isolates with resistance to both boscalid and pyraclostrobin, and it strongly suggests that there may be a major problem in controlling this important pathogen on kiwifruit. Copyright © 2010 Society of Chemical Industry  相似文献   

18.
The grey mould disease caused by Botrytis cinerea leads to substantial economic losses in strawberry production all over the world. Control of the disease requires an extensive amount of fungicide that is applied in varying complexes because the pathogen easily develops resistance against the active compounds. Planting of resistant cultivars seems to be a promising alternative for fruit growers, but there are currently no cultivars available combining resistance to B. cinerea with attractive horticultural traits. Breeding of new cultivars requires the effective identification of resistant strawberry genotypes; therefore the current study was aimed at the evaluation of strawberry genetic resources under controlled conditions by establishing an artificial inoculation assay. The method presented in this study is an artificial inoculation of ripe fruits with a defined spore suspension under laboratory conditions. The results show that this assay is fast and simple and leads to reproducible results that correlate with field observations. Over 3 years a total of 107 strawberry genotypes of the German National Fruit Genebank at the JKI in Dresden‐Pillnitz were evaluated. Five partly resistant genotypes, cultivars Diana, Joerica and Kimberly, and Fragaria virginiana ‘Wildmare Creek’ and F. vesca subsp. bracteata, were identified with mean disease levels of <20% at 6 days post‐inoculation. The obtained results are discussed with regard to future breeding activities.  相似文献   

19.
Botrytis cinerea isolates from pear blossoms (Pyrus communis) in South Africa were collected from four orchards in two production areas in the Western Cape. The cryptic species status based on vegetative‐incompatibility alleles of the Bc‐hch gene indicated that all the isolates belonged to B. cinerea. A microsatellite analysis of B. cinerea populations was performed to assess the genetic population structure. Total gene diversity (H) was high, with a mean of 0.69 across all populations. Some genotype flow was evident between orchards as indicated by the spread of microsatellite multilocus genotypes, in agreement with the moderate, but significant population differentiation among orchards (mean φPT = 0.118, P = 0.001). Index of association analyses (IA and r?d) suggest that the populations reproduce mostly asexually, even though mating type distribution did not differ significantly from a 1:1 ratio, suggesting frequency‐dependent selection. Isolates resistant to benomyl were evident in one orchard only. This orchard was also significantly differentiated from all other populations, suggesting infrequent localized selection for benomyl resistance. Overall, the findings of this study highlight the dangers of a mixed reproduction system, and stress the importance of regularly monitoring fungicide resistance levels towards developing more efficient management practices.  相似文献   

20.
为明确球孢白僵菌Beauveria bassiana定殖对番茄植株抗病性的影响及作用机理,采用灌根法将球孢白僵菌芽生孢子悬浮液接种于番茄植株内,并通过人工接种灰霉菌Botrytis cinerea评价球孢白僵菌定殖后番茄对灰霉病的抗性水平;检测灰霉菌胁迫下番茄植株不同位置叶片内球孢白僵菌的相对含量;测定番茄叶片内草酸氧化酶（oxalate oxidase,OXO）、几丁质酶（chitinase,CHI）和ATP合成酶（ATP synthase,atpA）3种抗病相关基因的表达量。结果表明,球孢白僵菌定殖能够提高番茄植株对灰霉病的抗性,接种灰霉菌第5天,番茄植株发病率、病斑直径和病情指数分别下降了61.6%、41.4%和26.4%;在灰霉菌胁迫下番茄植株内球孢白僵菌偏好于在病原菌感染位置定向聚集,并且引起植物抗病基因OXO、CHI和atpA的表达量上调。表明球孢白僵菌能通过内生定殖与植物互作提高植物抗病性,在植物病害生物防治领域有较大应用潜力。  相似文献   

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