[Objective] This study aimed to avoid and delay the generation of resis- tance in Botrytis cinerea to boscalid. [Method] The sensitivity of Botrytis cinerea to boscalid was tested by the mycelial growth rate method. T...[Objective] This study aimed to avoid and delay the generation of resis- tance in Botrytis cinerea to boscalid. [Method] The sensitivity of Botrytis cinerea to boscalid was tested by the mycelial growth rate method. The distribution of sensitivity variation of B. cinerea to boscalid in different regions was cleared, and the sen- sitivity baseline of B. cinerea from Liaoning Province to boscalid was established. [Result] The ECso values of B. cinerea strains from Liaoning Province ranged from 0.080 0 to 7.787 2μg/ml, and the highest ECho value was 97.34 times higher than the minimum. The average EC50 value （1.973μg/ml） of the 158 strains was treated as the baseline sensitivity of B. cinerea from Liaoning Province to boscalid. [Conclu- sion] It is essential to conduct a risk assessment of drug resistance in B. cinerea to boscalid.展开更多
Pyraclostrobin,a quinone outside inhibitor(QoI)fungicide,has been registered to control apple tree Valsa canker(AVC)caused by Valsa mali in China.However,there is no data available regarding the resistance risk of V.m...Pyraclostrobin,a quinone outside inhibitor(QoI)fungicide,has been registered to control apple tree Valsa canker(AVC)caused by Valsa mali in China.However,there is no data available regarding the resistance risk of V.mali to pyraclostrobin.In this study,the sensitivities of 120 V.mali isolates to pyraclostrobin were detected.The isolates were collected from apple orchards with no application of pyraclostrob at six provinces in China during 2013–2015,and showed similar sensitivity to pyraclostrobin.The EC_(50) values of these 120 V.mali isolates to pyraclostrobin ranged from 0.0014 to 0.0240μg/mL,indicating an excellent inhibitory efficacy of pyraclostrobin to the pathogen.The EC_(50) values were distributed as a unimodal curve with a mean value of 0.0091μg/mL,and the mean EC_(50) displayed correlation with geographic location.Meanwhile,three pyraclostrobin-resistant mutants(PR mutants)of V.mali were obtained using fungicide adaption method,with a resistance factor(RF)of 41.0,56.8 and 22.0,respectively.The mutants showed a stable resistance to pyraclostrobin after 10 transfers on pyraclostrobin-free medium.Comparing with the corresponding parental isolates,the hyphal growth,mycelial dry weight and pathogenicity of PR mutants were significantly reduced,but the number of propagules showed no significant difference.More importantly,no cross-resistance of PR mutants to pyraclostrobin,tebuconazole,difenoconazole,imazalil and thiophanate-methyl was detected.In conclusion,V.mali showed a moderate risk to pyraclostrobin,and pyraclostrobin could be used as an alternative fungicide to control AVC in the field in China.展开更多
Fungal pathogen Botrytis cinerea,the casual agent of gray mold of vegetables and fruits,has a high risk of developing resistance to fungicide.Tebuconazole,one kind of demethylation inhibitor(DMI)fungicides,has been in...Fungal pathogen Botrytis cinerea,the casual agent of gray mold of vegetables and fruits,has a high risk of developing resistance to fungicide.Tebuconazole,one kind of demethylation inhibitor(DMI)fungicides,has been increasingly applied for the control of tomato gray mold in China.However,very limited information is available on the resistance profile of B.cinerea to tebuconazole.In this study,the baseline sensitivity of B.cinerea to tebuconazole was determined based on 138 isolates from field sites having no history of DMI usage,with a mean EC_(50) value of 0.29μg/mL.Another 159 B.cinerea isolates collected in the greenhouse and field from 2011 to 2016 were demonstrated to have a shifted sensitivity to tebuconazole,with a mean EC_(50) value of 0.66μg/mL.EC_(50) values of 10 B.cinerea isolates with reduced sensitivity to tebuconazole were greater than 1.56μg/mL,and these reducedsensitive isolates had a fitness penalty in sporulation and conidial germination,but showed similar mycelial growth rate and pathogenicity with those of the sensitive isolates.Positive cross-resistance was observed only between tebuconazole and the other two DMIs difenoconazole and prochloraz,but not between tebuconazole and the non-DMIs iprodione,procymidone,or fludioxonil.In reduced-sensitive isolates,no amino acid variation was found in the BcCYP51 protein.When exposed to tebuconazole,the expression level of BcCYP51 increased in these reducedsensitive B.cinerea isolates as compared to sensitive ones,thus contributing to the reduced sensitivity of the pathogen to tebuconazole.Additionally,the nucleotide mutation observed in the 1200 bp upstream region of BcCYP51 had no correlation with the development of fungicide resistance in B.cinerea isolates.These findings will be helpful for the understanding of DMI resistance mechnism in B.cinerea.展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest of China(201303025)~~
文摘[Objective] This study aimed to avoid and delay the generation of resis- tance in Botrytis cinerea to boscalid. [Method] The sensitivity of Botrytis cinerea to boscalid was tested by the mycelial growth rate method. The distribution of sensitivity variation of B. cinerea to boscalid in different regions was cleared, and the sen- sitivity baseline of B. cinerea from Liaoning Province to boscalid was established. [Result] The ECso values of B. cinerea strains from Liaoning Province ranged from 0.080 0 to 7.787 2μg/ml, and the highest ECho value was 97.34 times higher than the minimum. The average EC50 value （1.973μg/ml） of the 158 strains was treated as the baseline sensitivity of B. cinerea from Liaoning Province to boscalid. [Conclu- sion] It is essential to conduct a risk assessment of drug resistance in B. cinerea to boscalid.
基金supported by the National Key R&D Program of China(2016YFD0201100).
文摘Pyraclostrobin,a quinone outside inhibitor(QoI)fungicide,has been registered to control apple tree Valsa canker(AVC)caused by Valsa mali in China.However,there is no data available regarding the resistance risk of V.mali to pyraclostrobin.In this study,the sensitivities of 120 V.mali isolates to pyraclostrobin were detected.The isolates were collected from apple orchards with no application of pyraclostrob at six provinces in China during 2013–2015,and showed similar sensitivity to pyraclostrobin.The EC_(50) values of these 120 V.mali isolates to pyraclostrobin ranged from 0.0014 to 0.0240μg/mL,indicating an excellent inhibitory efficacy of pyraclostrobin to the pathogen.The EC_(50) values were distributed as a unimodal curve with a mean value of 0.0091μg/mL,and the mean EC_(50) displayed correlation with geographic location.Meanwhile,three pyraclostrobin-resistant mutants(PR mutants)of V.mali were obtained using fungicide adaption method,with a resistance factor(RF)of 41.0,56.8 and 22.0,respectively.The mutants showed a stable resistance to pyraclostrobin after 10 transfers on pyraclostrobin-free medium.Comparing with the corresponding parental isolates,the hyphal growth,mycelial dry weight and pathogenicity of PR mutants were significantly reduced,but the number of propagules showed no significant difference.More importantly,no cross-resistance of PR mutants to pyraclostrobin,tebuconazole,difenoconazole,imazalil and thiophanate-methyl was detected.In conclusion,V.mali showed a moderate risk to pyraclostrobin,and pyraclostrobin could be used as an alternative fungicide to control AVC in the field in China.
基金supported by the National Key Research and Development Programs of China(2016YFD0201003,2016YFD0201305)also partially supported by the National High Technology Research and Development Program of China(No.2012AA101502).
文摘Fungal pathogen Botrytis cinerea,the casual agent of gray mold of vegetables and fruits,has a high risk of developing resistance to fungicide.Tebuconazole,one kind of demethylation inhibitor(DMI)fungicides,has been increasingly applied for the control of tomato gray mold in China.However,very limited information is available on the resistance profile of B.cinerea to tebuconazole.In this study,the baseline sensitivity of B.cinerea to tebuconazole was determined based on 138 isolates from field sites having no history of DMI usage,with a mean EC_(50) value of 0.29μg/mL.Another 159 B.cinerea isolates collected in the greenhouse and field from 2011 to 2016 were demonstrated to have a shifted sensitivity to tebuconazole,with a mean EC_(50) value of 0.66μg/mL.EC_(50) values of 10 B.cinerea isolates with reduced sensitivity to tebuconazole were greater than 1.56μg/mL,and these reducedsensitive isolates had a fitness penalty in sporulation and conidial germination,but showed similar mycelial growth rate and pathogenicity with those of the sensitive isolates.Positive cross-resistance was observed only between tebuconazole and the other two DMIs difenoconazole and prochloraz,but not between tebuconazole and the non-DMIs iprodione,procymidone,or fludioxonil.In reduced-sensitive isolates,no amino acid variation was found in the BcCYP51 protein.When exposed to tebuconazole,the expression level of BcCYP51 increased in these reducedsensitive B.cinerea isolates as compared to sensitive ones,thus contributing to the reduced sensitivity of the pathogen to tebuconazole.Additionally,the nucleotide mutation observed in the 1200 bp upstream region of BcCYP51 had no correlation with the development of fungicide resistance in B.cinerea isolates.These findings will be helpful for the understanding of DMI resistance mechnism in B.cinerea.
