稻瘟病菌对三环唑抗药性风险研究

Resistance Risk of Magnaporthe grisea to Tricyclazole

采用紫外线和亚硝基胍(MNNG)方法对辽宁省7个市最敏感稻瘟病菌进行抗性诱变。紫外线诱导获得1个低抗菌株UV-DL-8,1个中抗菌株UV-FS-10;100μg·mL-1 MNNG诱变获得3个低抗菌株MNNG-DL-8、MNNG-DD-9和MNNG-TL-7,2个中抗菌株MNNG-BX-4和MNNG-PJ-9。采用菌落直径法分别测定咪鲜胺和嘧菌酯与三环唑的交互抗药性情况,结果表明:三环唑与二者之间均不存在交互抗药性。从菌丝生长速率、产孢量和致病力3方面研究了抗性菌株生物学特性,结果表明:菌丝生长速率与菌株的敏感性EC50无关,可能与菌株的个体差异有关。各菌株产孢量与其对三环唑敏感性存在直线负相关,菌株敏感性越强,产孢量越大。菌株致病力与其对三环唑敏感性存在直线负相关,抗性越强的菌株,致病力越差。可以推断在田间出现抗药菌株时,抗药菌株也难以形成优势种群。

The induced resistance of Magnaporthe grisea to tricyclazole was conducted indoor by ultraviolet and MNNG. One low-resistant strain and one mid-resistant strain were obtained through ultraviolet. There were 3 low-resistant and 2 mid-resistant strains through MNNG induce. The EC50 and it＇s pertinence of 3 groups strains to tricyclazole, prochloraz and azoxystrobin were examined. The results indicated that there were no cross resistence among tricyclazole, prochloraz and azoxystrobin. The biological characristics of resistant strains were examined, including growth rate of fungi, spore amount and pathogenicity. The growth rate of Magnaporthe grisea had no relationship with sensitivity EC50 of strains, maybe it＇s decided by its own characteristics. There was a negative correlation between spore amount and the sensitive of strains to tricyclazole. The more the strain was sensitive to tricyclazole, the bigger the spore amount was. There was also a negative correlation between the pathogenicity and the sensitive of strains to tricyclazole. The pathogenicity of resistant strain was more weaker than sensitive strain. Therefore, even though there were resistant strains to tricyclazole in field, but it＇s difficult to become superior cluster.