玫烟色棒束孢(Isaria fumosorosea)侵染小菜蛾的表达谱分析

Transcriptome profiling of Plutella xylostella (Lepidoptera:Plutellidae) infected by entomopathogenic fungus Isaria fumosorosea

摘要:

【背景】昆虫病原真菌对寄主的侵染是一个十分复杂的过程，是多基因共同作用的结果。玫烟色棒束孢(Isaria fumosorosea) IFCF01菌株对小菜蛾具有很高的致病力，然而有关玫烟色棒束孢对小菜蛾致病的相关基因少见报道。【目的】筛选玫烟色棒束孢侵染小菜蛾相关基因，为更好地利用玫烟色棒束孢防治小菜蛾提供基因靶点。【方法】采用第二代高通量测序技术RNA-Seq，对玫烟色棒束孢侵染小菜蛾2–3龄幼虫4、8、12、16、24、30、36 h的虫菌混合样品(处理组)及纯培养玫烟色棒束孢(对照组)进行测序分析并筛选差异表达基因，结合生物信息学方法分析差异基因涉及的功能模块和信号通路。【结果】玫烟色棒束孢侵染小菜蛾混合样品与纯培养玫烟色棒束孢对照组对比分析共获得28 384个差异基因，其中显著差异表达基因274个，上调表达118个，下调表达156个。筛选获得的显著差异表达基因，特别是上调表达基因可能与玫烟色棒束孢对小菜蛾的侵染有关。GO二级分类显示，差异表达基因能够注释到36个GO条目中，包含18个生物学过程、9个细胞组分和9个分子功能。KEGG通路分析显示共有171个差异表达基因(differentially expressed gene，DEG)注释到132个通路中，其中有66个DEG显著富集在14个通路中。这些显著差异表达基因中大部分为玫烟色棒束孢侵染过程中潜在致病毒力相关基因。【结论】本研究为筛选玫烟色棒束孢侵染小菜蛾致病相关基因提供重要数据库，也为阐明玫烟色棒束孢对小菜蛾的侵染机制提供基础。

Abstract:

Background]The infection of entomopathogenic fungi is a complex process resulted from the joint action of multiple genes.The Isaria fumosorosea isolate IFCF01 has high pathogenicity to Plutella xylostella.However,there are few reports on the genes related to the pathogenicity of I. fumosorosea to P. xylostella.[Objective]This study aims to explore the genes related to the infection of I. fumosorosea to P. xylostella,so as to reveal the pathogenic mechanism of I. fumosorosea and provide reference for the application of I. fumosorosea in the control of P. xylostella.[Methods] We performed high-throughput RNA sequencing to compare the transcriptomes of I. fumosorosea pure culture (control group) and the mixed samples of 2nd–3rd instar larvae of P. xylostella infected by I. fumosorosea for 4,8,12,16,24,30,and 36 h (treatment group) and mined the differentially expressed genes (DEGs) between the two groups.The functional modules and signaling pathways involving the DEGs were analyzed by bioinformatics method.[Results]A total of 28 384 DEGs were screened out,including 274 significant DEGs (118 up-regulated and 156 down-regulated ones).The significant DEGs screened out in this study,especially the up-regulated ones,were related to the infection.We conducted GO annotation to analyze the DEGs and found 36 GO terms,which included 18 biological processes,9 cellular components,and 9 molecular functions.There were 171 DEGs enriched in 132 KEGG pathways,of which 66 DEGs were significantly enriched in 14 pathways.Further analysis showed that many DEGs were virulence-associated genes during the infection.[Conclusion]The findings generated from this study provide a bioinformatic database for screening the pathogenic genes related to the infection of I. fumososea in P. xylostella and lays a theoretical foundation for elucidating the mechanism of I. fumosorosea infecting P. xylostella.