浙江省果蔬灰霉病菌对嘧菌酯的抗药性研究

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

采用菌丝生长速率法,连续监测了2010—2012年间浙江省果蔬灰霉病菌对QoI类杀菌剂嘧菌酯的敏感性变化。结果表明:病菌群体中的低敏感性亚群体的比例明显上升,EC50值>5 mg/L菌株的比例分别为12.5%、15.8%和28.3%;在菌丝生长阶段和孢子萌发阶段,旁路氧化在灰霉病菌对嘧菌酯敏感性中的平均相对贡献值(F)分别为2.91±0.89和5.72±2.82;嘧菌酯抗药性菌株的菌丝生长速率、产孢量、产菌核数和致病力与敏感菌株相比无显著差异。抗药性分子机制研究表明,灰霉病菌中存在2种类型的cyt b基因:Ⅰ型cyt b基因在第143位密码子后紧跟内含子;Ⅱ型cyt b基因在第143位密码子后没有紧跟内含子。大多数的灰霉病菌菌株属于Ⅱ型。Ⅰ型菌株均为嘧菌酯敏感菌株,Ⅱ型菌株为嘧菌酯敏感菌株或抗性菌株。抗性菌株的cyt b基因的第143位密码子由甘氨酸(GGC)突变为了丙氨酸(GCC),抗药性机制为G143A。

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 typeⅠ isolates have introns closely followed the codon 143 in cyt b gene and the type Ⅱisolates 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 Ⅱisolates 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.