Laboratory of Invertebrate Pathology and Applied Microbiology, College of Biotechnology, Southwest University, Chongqing, 400716, China.
Department of Medical Microbiology, School of Basic Medical Science, Hubei University of Medicine, Shiyan, Hubei, 442000, China.
Microb Pathog. 2021 May;154:104824. doi: 10.1016/j.micpath.2021.104824. Epub 2021 Mar 7.
Typical entomopathogenic filamentous fungi such as Beauveria bassiana infect susceptible hosts via penetration of insect cuticle. The pathogenicity of B. bassiana strain to diverse insect hosts is different. While the molecular mechanisms of B. bassiana adapt to different insects are not well clear. B. bassiana GXsk1011 is a hyper-virulent strain from silkworm, which was investigated on the metabolic responses to three cuticle extracts of Bombyx mori, Helicoverpa armigera and Clanis bilineata at 24 h by RNA-seq method. A total of 638 up- and 400 down-regulated differentially expressed genes (DEGs) were identified in B. bassiana grown on H. armigera compared with B. mori, and 910 up- and 401 down-regulated genes for C. bilineata compared with B. mori. Functional categorization showed that DEGs are mainly involved in metabolic processes, localization, catalytic activity and transporter activity. Analysis of 20 highest fold change genes in DEGs showed that when B. bassiana transferred to non-original hosts as H. armigera and C. bilineata, the adhesion (Mad1), protease (Pr2) and cell surface protein (BBA_09174), etc. were down-regulated. While the class III chitinase ChiA2 (BBA_05353, Bbchi-17), major allergen Asp f 2-like protein (BBA_05395, Bb-f2) and nonribosomal peptide synthase, etc. were up-regulated. The secretory lipase that responded to H. armigera and the phosphate permease responded to C. bilineata were also up-regulated in the Top 20 DEGs. These special expressed genes indicate when the B. bassiana transferred to non-original hosts (or called as non-natural hosts), the strain appeared the changes of metabolic response and infection strategies to adapt to new hosts, and implied the key actions of infected adaptation were to break the barrier of different cuticle chitin component and against the immune stress of hosts. This study provided an insight into the B. bassiana that with wide host ranges how to adapt to infect different insect hosts, which will help us to further understand the pathogenesis of B. bassiana infection.
典型的昆虫病原丝状真菌，如球孢白僵菌，通过穿透昆虫的表皮来感染易感宿主。球孢白僵菌对不同昆虫宿主的致病性不同。然而，球孢白僵菌适应不同昆虫的分子机制尚不清楚。球孢白僵菌 GXsk1011 是一种来自家蚕的高毒力菌株，本研究采用 RNA-seq 方法研究了该菌株在 24 h 时对家蚕、棉铃虫和双线嗜粘液蛞蝓三种表皮提取物的代谢反应。与家蚕相比，在球孢白僵菌生长于棉铃虫时，共鉴定出 638 个上调和 400 个下调的差异表达基因（DEGs），而与家蚕相比，在球孢白僵菌生长于双线嗜粘液蛞蝓时，有 910 个上调和 401 个下调的 DEGs。功能分类表明，DEGs 主要参与代谢过程、定位、催化活性和转运活性。对 DEGs 中 20 个最高倍数变化基因的分析表明，当球孢白僵菌转移到非原始宿主，如棉铃虫和双线嗜粘液蛞蝓时，粘附（Mad1）、蛋白酶（Pr2）和细胞表面蛋白（BBA_09174）等下调。而 III 类几丁质酶 ChiA2（BBA_05353，Bbchi-17）、主要过敏原 Asp f 2 样蛋白（BBA_05395，Bb-f2）和非核糖体肽合酶等上调。对棉铃虫有反应的分泌脂肪酶和对双线嗜粘液蛞蝓有反应的磷酸透酶也在 DEGs 前 20 名中上调。这些特殊表达的基因表明，当球孢白僵菌转移到非原始宿主（或称为非天然宿主）时，该菌株的代谢反应和感染策略发生变化，以适应新宿主，这意味着感染适应性的关键作用是打破不同表皮几丁质成分的屏障，并抵抗宿主的免疫应激。本研究深入了解了具有广泛宿主范围的球孢白僵菌如何适应感染不同的昆虫宿主，这将有助于我们进一步了解球孢白僵菌感染的发病机制。
