油菜菌核病菌对腐霉利的抗性诱变及抗药菌株的生物学特性

从江苏省镇江市和扬州市采集菌核病植株的茎，从中分离获得油菜菌核病菌（Sclerotinia sclerotiorum）单菌核菌株。32个野生型菌株药剂敏感性（EC50）频率分布数据显示，病菌对腐霉利的敏感基线EC50值为0．1981±0．0220μg／mL，MIC（最小抑菌浓度）值为1．1±0．1595μg／mL。实验未发现田间抗腐霉利菌株。通过室内紫外线和药剂诱导，获得多株高抗腐霉利突变体（EC50〉1000μg／mL）。这些抗性突变株经转管培养5～20代后抗药性稳定。它们对同类药剂异菌脲和有机磷类甲基立枯磷也表现高抗，但对苯并咪唑类多菌灵敏感。与野生型敏感菌株相比，抗腐霉利突变株菌丝生长较慢，对油菜茎秆和叶片的致病力均较弱。

Procymidone resistant mutagenesis of Sclerotinia sclerotiorum isolated from rapeseed stem

Wild strains of Sclerotinia sclerotiorum from rotten rapeseed stem, gathered in fields of Zhenjiang City and Yangzhou City in Jiangsu Province, were used to study the fungicide resistance and mutagenesis. The resistance to procymidone of 32 wild isolates was investigated. Resistant frequency distribution results showed that the sensitivity baseline of the pathogen was EC50 0. 198 1 ± 0.022 0μg/mL and MIC （ minimum inhibitory concentration） 1.1 ±0. 159 5μg/mL. No procymidone-resistant wild strains were found in the experiment. While after UV or procymidone inducement, the procymidone-resistant mutants emerged with EC50 higher than 1 000μg/mL. Their resistance was stable after subcultured for twenty generations on PSA（ potato sugar agar）. It was also found that procymidone-resistant mutants were highly resistant to dicarboximide fungicide iprodione and organophosphorus fungicide tolclofos-methyl, although they were sensitive to benzimidazole fungicide carbendazim. Furthermore, the resistant mutants were found to grow slower and had less virulence to rapeseed stem and leaves than sensitive wild types.