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

发布时间：2018-08-06 13:30

【摘要】：为评价西瓜蔓枯病菌对啶酰菌胺的抗性风险,了解其抗性机理,室内通过药剂驯化方法获得2株啶酰菌胺的抗性突变体XF21-3和YC60-1,测定了抗性突变体的生物学特性,并通过对Sdh B基因片段的测序比对,分析了西瓜蔓枯病菌对啶酰菌胺的抗性机理。生物测定结果表明:啶酰菌胺对2株抗性突变体的EC_(50)值分别为108和124μg/m L,抗性倍数(RR)分别为1 007和1 347,均为高抗菌株;抗性突变体的菌丝生长速率和产孢量均大于亲本菌株,但其致病性与亲本菌株无显著差异,对外界环境渗透压的敏感性低于亲本菌株;此外,啶酰菌胺与萎锈灵、戊唑醇、乙霉威及醚菌酯之间均不存在交互抗性,但与噻呋酰胺之间存在交互抗性。Sdh B基因片段测序及比对结果表明,高抗性突变体中Sdh B亚基277位上的氨基酸所对应的碱基由CAC突变为TAC,即由组氨酸(His)突变为酪氨酸(Tyr)。研究表明,西瓜蔓枯病菌在药剂选择压力下容易形成啶酰菌胺的抗性群体,且抗性突变体的离体适合度高于亲本菌株,此外,啶酰菌胺与同类型杀菌剂噻呋酰胺之间存在交互抗性,因此认为西瓜蔓枯病菌对啶酰菌胺具有中等抗性风险;同时进一步验证了Sdh B亚基277位上的氨基酸突变(His→Tyr,CAC→TAC)是西瓜蔓枯病菌对啶酰菌胺产生抗性的原因。
[Abstract]:In order to evaluate the risk of resistance of watermelon vine blight pathogen to pyridamine and understand its resistance mechanism, two resistant mutants XF21-3 and YC60-1 were obtained by medicament acclimation in laboratory. The biological characteristics of the resistant mutants were determined. By sequencing and comparing the Sdh B gene fragments, the mechanism of resistance to pyrimidine was analyzed. The results of bioassay showed that the EC50 values of the two resistant mutants were 108 and 124 渭 g / mL, respectively, and the resistance multiple (RR) were 1 007 and 1 347, respectively, and the hyphal growth rate and sporulation production of the resistant mutants were higher than those of the parent strains. However, there was no significant difference between the pathogenicity and parent strain, the sensitivity to external osmotic pressure was lower than that of parent strain, in addition, there was no cross resistance between pyridamine and atropine, tebuconazole, ethyl tetrarb and etheromycin, but the sensitivity to external environment osmotic pressure was lower than that of parent strain. However, the sequencing and comparison of the Sdh B gene fragment with thiofuroxime showed that the amino acid corresponding to the amino acid at the 277 position of the Sdh B subunit in the high resistance mutants mutated from CAC to TAC, that is, from histidine (His) to tyrosine (Tyr). The results showed that the resistant population was easily formed under the drug selection pressure, and the in vitro fitness of the resistant mutant was higher than that of the parent strain. There was cross resistance between acidomide and thiofuroxime of the same type of fungicides, so it was considered that the pathogen of watermelon vine blight had moderate resistance risk to acrylmylamine. At the same time, the amino acid mutation on Sdh B subunit 277 (His Tyr-CAC TAC) was proved to be the cause of the resistance of watermelon vine blight pathogen to acrylmylamine.
【作者单位】：西南大学植物保护学院;
【分类号】：S436.5

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