Role of gliotoxin in the symbiotic and pathogenic interactions of Trichoderma virens
Role of gliotoxin in the symbiotic and pathogenic interactions of Trichoderma virens
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DOI：
10.1099/mic.0.079210-0
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发表时间：
2014-10-01
期刊：
影响因子：
2.8
通讯作者：
Kenerley, Charles M.
中科院分区：
文献类型：
--
作者：
Vargas, Walter A.;Mukherjee, Prasun K.;Kenerley, Charles M.
利用基因破坏策略，我们在植物有益真菌木霉（Trichoderma virens）的gliP位点上产生突变体，这些突变体不再能够产生胶质毒素。表型分析表明，与WT菌株相比，滑动破坏突变体生长更快，对氧化应激更敏感，并且表现出稀疏的菌落边缘。在平板对抗实验中，缺乏胶质毒素产生的突变体对卵霉菌、最后圆霉和坏死性真菌病原体菌核菌不起作用，但保留了对solani根丝核菌的真菌寄生能力。土壤生物防治试验表明，突变体不能保护棉花幼苗免受最后叶枯病菌的侵害，而WT菌株对棉花幼苗的防治效果较好。然而，这些突变体在保护棉花幼苗免受番茄枯萎病的侵害方面与WT菌株一样有效。与WT相比，胶质毒素产生的减少也导致突变体攻击菌核的能力降低。在突变体定殖的菌核中添加外源胶质毒素部分恢复了它们的降解能力。有趣的是，就像在烟曲霉（一种机会性人类病原体）中一样，胶质毒素被发现参与了T. virens对蜡蛾幼虫的致病性。通过与烟曲霉的gliP基因的互补，恢复了T. virens产生胶质毒素的损失。因此，我们已经证明了假定的葡萄球菌gliP簇负责胶质毒素的生物合成，胶质毒素参与了这种植物有益真菌的分枝寄生和生物防治特性。
Using a gene disruption strategy, we generated mutants in the gliP locus of the plant-beneficial fungus Trichoderma virens that were no longer capable of producing gliotoxin. Phenotypic assays demonstrated that the gliP-disrupted mutants grew faster, were more sensitive to oxidative stress and exhibited a sparse colony edge compared with the WT strain. In a plate confrontation assay, the mutants deficient in gliotoxin production were ineffective as mycoparasites against the oomycete, Pythium ultimum, and the necrotrophic fungal pathogen, Sclerotinia sclerotiorum, but retained mycoparasitic ability against Rhizoctonia solani. Biocontrol assays in soil showed that the mutants were incapable of protecting cotton seedlings from attack by P. ultimum, against which the WT strain was highly effective. The mutants, however, were as effective as the WT strain in protecting cotton seedlings against R. solani. Loss of gliotoxin production also resulted in a reduced ability of the mutants to attack the sclerotia of S. sclerotiorum compared with the WT. The addition of exogenous gliotoxin to the sclerotia colonized by the mutants partially restored their degradative abilities. Interestingly, as in Aspergillus fumigatus, an opportunistic human pathogen, gliotoxin was found to be involved in pathogenicity of T. virens against larvae of the wax moth, Galleria mellonella. The loss of gliotoxin production in T. virens was restored by complementation with the gliP gene from A. fumigatus. We have, thus, demonstrated that the putative gliP cluster of T. virens is responsible for the biosynthesis of gliotoxin, and gliotoxin is involved in mycoparasitism and biocontrol properties of this plant-beneficial fungus.