Mol Plant Microbe Interact. 2014 Jul;27(7):725-32. doi: 10.1094/MPMI-12-13-0365-R.
ATP-binding cassette (ABC) transporters mediate active efflux of natural and synthetic toxicants and are considered to be important for drug tolerance in microorganisms. In biological control agents (BCA), ABC transporters can play important roles in antagonism by providing protection against toxins derived from the fungal prey and by mediating the secretion of endogenous toxins. In the present study, we generated deletion and complementation strains of the ABC transporter abcG5 in the fungal BCA Clonostachys rosea to study its role in xenobiotic tolerance and antagonism. Gene expression analysis shows induced expression of abcG5 in the presence of the Fusarium mycotoxin zearalenone (ZEA), secreted metabolites of F. graminearum, and different classes of fungicides. Phenotypic analysis of abcG5 deletion and complementation strains showed that the deletion strains were more sensitive towards F. graminearum culture filtrates, ZEA, and iprodione- and mefenoxam-based fungicides, thus suggesting the involvement of abcG5 in cell protection. The ΔabcG5 strains displayed reduced antagonism towards F. graminearum in a plate confrontation assay. Furthermore, the ΔabcG5 strains failed to protect barley seedlings from F. graminearium foot rot disease. These data show that the abcG5 ABC transporter is important for xenobiotic tolerance and biocontrol traits in C. rosea.
三磷酸腺苷结合盒（ABC）转运蛋白介导天然和合成毒物的主动外排，被认为是微生物药物耐受性的重要因素。在生物防治剂（BCA）中，ABC 转运蛋白可通过提供对真菌猎物衍生毒素的保护以及介导内源性毒素的分泌来在拮抗作用中发挥重要作用。在本研究中，我们生成了真菌生物防治剂玫瑰座腔菌（Clonostachys rosea）中 ABC 转运蛋白 abcG5 的缺失和互补菌株，以研究其在外源生物耐受和拮抗作用中的作用。基因表达分析表明，abcG5 在镰刀菌真菌毒素玉米赤霉烯酮（ZEA）、禾谷镰刀菌分泌的代谢物以及不同类别的杀真菌剂存在的情况下表达被诱导。abcG5 缺失和互补菌株的表型分析表明，缺失菌株对禾谷镰刀菌培养滤液、ZEA 以及基于异菌脲和甲霜灵的杀真菌剂更敏感，这表明 abcG5 参与了细胞保护。ΔabcG5 菌株在平板对峙测定中对禾谷镰刀菌的拮抗作用降低。此外，ΔabcG5 菌株未能保护大麦幼苗免受禾谷镰刀菌根腐病的侵害。这些数据表明，abcG5 ABC 转运蛋白对玫瑰座腔菌的外源生物耐受和生物防治特性很重要。
