草莓灰霉病菌对嘧菌酯的抗性检测及抗性菌株的生物学特性研究

Detection of resistance to azoxystrobin and characterization of the azoxystrobin-resistant isolates in Botrytis cinerea from strawberry

由灰葡萄孢(Botrytis cinerea Pers.)引起的草莓灰霉病是严重危害草莓的病害之一。为了解草莓灰霉病菌对杀菌剂嘧菌酯的抗性情况,本研究针对2012年从国内10省市采集和分离的134株草莓灰霉病菌菌株,利用特异性引物BcAR-F/BcAR-R扩增其cytb基因的部分序列,进行了嘧菌酯抗性的分子检测;对检测出的抗性菌株在嘧菌酯浓度分别为22.4、112和224μg·mL^(-1)的含药培养基上进行抗性验证;此外,还比较了抗性菌株与敏感菌株主要生物学性状的差异。结果表明,有54个菌株对嘧菌酯表现抗性,均属于中等抗性水平,占检测总数的40.3%,分布于北京市、湖北、江苏、河北、辽宁和四川各省;对15个抗性菌株cytb基因的序列分析表明,其第143位发生突变,由甘氨酸变为丙氨酸;对随机选取的4株抗性菌株和2株敏感菌株的适合度测定结果发现,抗性菌株和敏感菌株在最适生长温度、菌落生长速度、孢子萌发率方面没有表现出规律性差异,但抗性菌株的产孢量和致病力均显著低于敏感菌株。

Gray mold of strawberry caused by Botrytis cinerea Pers. is one of the most serious diseases on strawberry. In order to understand the resistance of B. cinerea from strawberry to azoxystrobin, a systemic fungi- cide commonly used to protect plants and fruits/vegetables from fungal diseases, in China, 134 isolates were collected from 10 provinces or cities in 2012 and their resistance to the fungicide was detected using PCR with specific primers BcAR-F/BcAR-R. The resistant isolates were confirmed on PDA medium supplemented with the fungicide. The biological characteristics of the azoxystrobin-resistant and -sensitive isolates were also compared. Our resulfs indicated that 54 isolates （40.3%） from Beijing, Hubei, Jiangsu, Hebei, Liaoning and Sichuan, were moderate resistant to azoxystrobin. It was found that a glycine was replaced by an alanine at position 143 in cytb gene in all the 15 resistant isolates. There were no significant differences in optimum growth temperature, colonial growth rate, and spore germination rate when 4 azoxystrobin-resistant and 2 azoxystrobin-sensitive iso- lates were randomly selected and compared. However, sporulation and virulence to strawberry leaves of resistant isolates were significantly decreased when compared to the azoxystrobin-sensitive isolates.