黄瓜霜霉病菌对双炔酰菌胺的敏感基线及其抗性突变体生物学性状研究

为建立黄瓜霜霉病菌对双炔酰菌胺的敏感基线及评估其抗性风险,采用叶盘漂浮法测定了采自河北、山东未使用过羧酸酰胺类(CAAs)药剂地区的69株黄瓜霜霉病菌(Pseudoperonospora cubensis)对双炔酰菌胺的敏感性,并对黄瓜霜霉病菌抗双炔酰菌胺突变体的获得方法及突变体的生物学性状进行了研究。结果表明:69株黄瓜霜霉病菌对双炔酰菌胺的平均EC50值为(0.358±0.144)μg/mL,不同敏感性菌株的频率呈连续单峰曲线分布,未发现敏感性下降的亚群体,因此可将其作为黄瓜霜霉病菌对双炔酰菌胺的敏感基线;通过药剂驯化的方法未获得黄瓜霜霉病菌抗双炔酰菌胺的突变体;而通过紫外诱导的方法获得了6个抗双炔酰菌胺的突变体,其抗性水平介于5.74~22.96倍之间,突变频率为1.09×10-7,适合度显著低于其亲本菌株,且抗药性不能稳定遗传;双炔酰菌胺与甲霜灵、嘧菌酯、霜脲氰、氟吡菌胺之间无交互抗性关系,与烯酰吗啉之间有交互抗性关系。据此推测黄瓜霜霉病菌对双炔酰菌胺的抗性风险为低到中等。

Studies on baseline sensitivity to mandipropamid and biological characteristics of resistant mutants of Pseudoperonospora cubensis

The objectives of the study were to establish the baseline sensitivity of P.cubensis to mandipropamid and to assess the resistance risk of P.cubensis to mandipropamid.The sensitivity to mandipropamid of 69 P.cubensis strains collected from the areas in Hebei and Shandong province where no mandipropamid had been used before were determined by leaf disc floating test,UV mutagensis and fungicide adaptation test were conducted to acquire resistant mutants to mandipropamid and to clarify the biological characteristics of the resistant mutants.The results showed that the frequency of strains with different sensitivity to mandipropamid distributed as a unimodal curve,there was no sub-group with sensitivity declined,and the mean EC50 value was (0.358± 0.144) μ g/mL.Six mutants of P.cubensis resistant to mandipropamid were obtained by UV mutagensis with the resistance factors ranging from 5.74 to 22.96 fold,and the mutation frequency was 1.09×10-7,the fitness of six mandipropamid-resistant mutants was significantly lower than that of their respective parental strains,and the resistance could not be inherited stably.No cross resistance relationship existed between mandipropamid and metalaxyl,azoxystrobin,cymoxanil or fluopicolide,but the cross resistance was existed between mandipropamid and dimethomorph.In a word,it was suggested that P.cubensis had a low to medium risk of developing resistance to mandipropamid.