农药学学报2017，Vol.19Issue(3)：307-315,9.DOI:10.16801/j.issn.1008-7303.2017.0040
西瓜蔓枯病菌啶酰菌胺抗性突变体的生物学特性研究及其Sdh B基因位点检测
Study on biological characteristics and resistance molecular mechanism of Didymella bryoniae to boscalid
摘要
Abstract
The resistance risk of Didymella bryoniae against boscalid was valuated and the resistance mechanism was investigated. By using fungicide adaptation in door, the boscalid-resistant mutants XF21-3 and YC60-1 were obtained, and their biological characteristics were investigated. The partial Sdh B gene sequences of resistant mutants were sequenced to study the molecular mechanism of resistance of D. bryoniae to boscalid. Results showed that the EC50 values of two resistant mutants, XF21-3 and YC60-1, were 108 and 124 μg/mL, with corresponding resistance ratio of 1007 and 1347, respectively. The mycelial growth rate and sporulation of two resistant mutants were better than that of their corresponding parents. There is no significant difference in pathogenicity between resistant mutants and their parents. However, resistant mutants showed reduced sensitivity to the high osmotic pressure compared to parental strains. Besides, the resistant mutants had cross-resistance with thifluzamid and had no cross-resistance with carboxin, diethofencrab, tebuconazole, and kresoxoim-methyl. The comparison ofSdh B gene sequencing showed that resistant mutants harbored the point mutation at position 277 inSdh B subunit with amino acid changing from histidine to tyrosine. The findings indicated that it is easy forD. bryoniae to produce boscalid-resistance under higher selection pressure, and thein vitro fitness for resistant mutants was higher than that of sensitive strains. The results also showed that boscalid was a medium resistance risk fungicide, because the boscalid-resistant mutants showed cross-resistance between boscalid and thifluzamid. Finally, the point mutation at codon 277 (His→Tyr, CAC→TAC) inSdh B may confer resistance ofD. bryoniae to boscalid.关键词
西瓜蔓枯病菌/啶酰菌胺/抗药性/生物学特性/SdhB亚基/基因突变Key words
Didymella bryoniae/boscalid/resistance/biological characteristics/Sdh B gene/gene mutation分类
农业科技引用本文复制引用
王少秋,李雨,杨宇衡,余洋,毕朝位..西瓜蔓枯病菌啶酰菌胺抗性突变体的生物学特性研究及其Sdh B基因位点检测[J].农药学学报,2017,19(3):307-315,9.基金项目
公益性行业(农业)科研专项(201303023). （农业）
