Study on resistance of Botrytis cinerea to azoxystrobin collected from fruits and vegetables in Zhejiang Province

Shift of the sensitivity of Botrytis cinerea to azoxystrobin(a Qo center inhibitor,QoI) collected from strawberry,tomato,eggplant and grape greenhouses in Zhejiang province was monitored by the method of mycelial growth rate from 2010 to 2012.The results showed that there was a significantly increased tendency of the percentage of the low sensitivity subgroups of B.cinerea.The percentage of isolates with EC50>5 mg/L was 12.5%,15.8%,and 28.3%,respectively.The mean factor values for the impact of alternative respiration on sensitivity to azoxystrobin were 2.91±0.89 and 5.72±2.82 during mycelial growth and spore germination,respectively.And,there was no significant difference in mycelial growth,sporulation,sclerotial production,and pathogenicity between azoxystrobin resistant and sensitive isolates.Further research indicated that there were two types of cyt b gene in B.cinerea.The type Ⅰ isolates have introns closely followed the codon 143 in cyt b gene and the type Ⅱ isolates have no introns closely followed the codon 143 in cyt b gene.Most of B.cinerea isolates belong to the type Ⅱ.All the type Ⅰ isolates were azoxystrobin sensitive.The type Ⅱ isolates were azoxystrobin sensitive or resistant.The G143A point mutation predicted to cause a change from glycine to alanine at codon 143 of cyt b gene was found in all resistant isolates.