江苏省稻瘟病菌对稻瘟灵的抗药性监测及特性分析

Sensitivity test and characteristic analysis of Magnaporthe oryzae to isoprothiolane in Jiangsu Province

近几年我国山东省、黑龙江省、辽宁省等多地稻瘟病菌(Magnaporthe oryzae)已对稻瘟灵杀菌剂产生了抗药性。江苏省是我国水稻生产大省,为明确江苏省稻瘟病菌对稻瘟灵的敏感性,本研究分离了2019年采自江苏省6个地区的稻瘟病菌单孢菌株101株,监测到13株稻瘟病菌为稻瘟灵的抗药性菌株,全省稻瘟病菌对稻瘟灵的抗性频率为12.9%。除仪征市未监测到抗药性菌株外,其他5个地区徐州市、淮安市、连云港市、东台市以及宜兴市稻瘟病菌对稻瘟灵的抗性频率分别为40.0%、33.3%、11.5%、5.0%和5.9%。利用菌丝生长速率法对其进行了敏感性测定,结果表明,这13株抗药性菌株的EC;值为15.0~20.6 mg·L^(-1),其抗性水平在3.6~5.0之间,均表现为低抗水平。进一步对筛选到的稻瘟灵抗性菌株适合度分析发现,只有2株抗性菌株2019-33和2019-45适合度降低,其余抗性菌株均无明显变化。这13株抗性菌株与嘧菌酯、咪鲜胺以及稻瘟酰胺均不存在交互抗性,且抗性相关基因MoIRR未发生任何位点突变。

In recent years,resistance of Magnaporthe oryzae,which causes rice blast,to isoprothiolane has been reported in several provinces,such as Shandong,Heilongjiang,and Liaoning Province.In the current study,101 M.oryzae isolates were collected from rice field in Jiangsu Province in 2019,and 13 isolates were consi-dered as isoprothiolane-resistant isolates.The resistance frequency was 12.9%in Jiangsu Province while resistance frequencies were 40.0%,33.3%,11.5%,5.0%and 5.9%in Xuzhou,Huai’an,Lianyungang,Dongtai,and Yixing city,respectively.However,no isoprothiolane-resistant isolate was detected in Yizheng city.The EC;values of all 13 isoprothiolane-resistant isolates were ranged from 15.0 to 20.6 mg·L^(-1),and were lowly resistant to isoprothiolane with resistance factors(RF)less than 5.0.Only 2 isolates(2019-33 and 2019-45)from the 13 isoprothiolane-resistant isolates showed reduced fitness.Furthermore,all the 13 isoprothiolane-resistant isolates had no cross-resistance with pyrimethanil,imidazamine and ricinamide,and there was no mutation in the gene MoIRR which was reported to be related with the isoprothiolane resistance in M.oryzae.