Homologs of bacterial heat-labile enterotoxin subunit A contribute to development, stress response, and virulence in filamentous entomopathogenic fungus Beauveria bassiana

Frontiers in Immunology

Immunology

Kang Wei¹  Jin-Li Ding¹  Ming-Guang Feng¹  Sheng-Hua Ying¹ 

[1] Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China;

关键词: Beauveria bassiana;    enterotoxin;    development;    virulence;    stress response;   

DOI  :  10.3389/fimmu.2023.1264560

 received in 2023-07-21, accepted in 2023-09-04,  发布年份 2023

来源: Frontiers

【 摘 要 】

IntroductionEnterotoxigenic bacteria commonly excrete heat-labile enterotoxins (LT) as virulence factors that consist of one subunit A (LTA) and five B subunits (LTB). In fungi, there are a large number of genes encoding the homologs of LTA, but their biological roles remain largely unknown. MethodsIn this study, we identified 14 enterotoxin_A domain proteins in filamentous fungus B. bassiana in which five proteins were functionally characterized. ResultsFive proteins displayed diverse sub-cellular localizations but perform convergent functions in stress response, development, and virulence. The loss of five LTA genes resulted in significant reduction in conidial production, blastospore formation, and the increased sensitivity to oxidative and cell wall –perturbing stresses. The virulence of five disruptants was notably weakened as indicated by topical and intrahemocoel injection assays. Notably, the loss of these five proteins led to the significant changes in the carbohydrate profiles of cellular surface, which induced the enhanced host immune reactions of encapsulation and melanization. DiscussionThus, LTA proteins contribute to the fungus–host interaction via maintaining the carbohydrate profiles of cellular surface. This study expands our understanding of the enterotoxin_A domain proteins in fungal physiology and deepens mechanisms involved in the lifestyle of fungal insect pathogens.

【 授权许可】

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Copyright © 2023 Ding, Wei, Feng and Ying