比较两种昆虫病原真菌中结构相似的ATP结合匣转运蛋白的抗氧化力与多药抗性

Antioxidation and multidrug resistance of structure-similar ATP-binding cassette transporter proteins in two fungal entomopathogens

【目的】比较分析球孢白僵菌(Beauveria bassiana)BbT1和玫烟棒束孢(Isaria fumosorosea)IfT1两种结构相似的ATP结合匣转运蛋白的生物学功能。【方法】基于Bb2860野生株构建BbT1的敲除株和回补株,并将IfT1在BbT1敲除株中异源重组表达,比较各菌株的表型变化。【结果】与野生株、回补株及异源重组株相比,敲除株对20-40 mmol/L过氧化氢和2-8 mmol/L甲萘醌氧化胁迫的抵抗力下降27%-2.1倍,对多菌灵、伊曲康唑、菌核净、放线菌酮、乙嘧酚和4-硝基喹啉N-氧化物等不同类型化学药物的抗药性下降28%-4.7倍,对斜纹夜蛾Spodoptera litura二龄幼虫的毒力下降20%左右,而野生株、回补株及异源重组株之间无任何表型的显著差异。【结论】BbT1和IfT1是结构相似且功能一致的转运蛋白,分别是两种生防真菌多药抗性的决定因子之一,因参与抗氧化反应而对毒力有所贡献。

[ Objective] Structure-similar ATP-binding cassette （ABC） transporter proteins, BbT1 in Beauveria bassiana （Bb） and IfT1 in Isaria fumosorosea （If）, were characterized. [ Methods ] Various phenotypes including cellular antioxidant response, muhidrug resistance and virulence were compared between wild-type strain and the constructed mutants ABbT1 , △BbT1/BbT1 and △BbT1/IfT1. [ Results] Compared with the wild-type, ABbT1/BbT1 and ABbT1/ IfF1 strains showing no significant changes in examined phenotypes, ABbT1 became 27% to 2. 1-fold less tolerant to the oxidative stress of 20 -40 mmol/L H202 and 2 -8 mmol/L menadione, 28% to 4.7-fold less resistant to carbendazim, itraconazole, dimetachlone, cycloheximide, ethirimol and 4-nitroquinoline N-oxide, and about 20% less virulent to the second-instar larvae of Spodoptera litura. [ Conclusion] The ABC transporter proteins BbT1 and IfT1 are similar not only in sequence structure but also in biological function, act as one of the determinants for the muhidrug resistance of Bb and If, and also contribute to the fungal virulence due to involvement in cellular antioxidant response.