玫烟色棒束孢诱导的小菜蛾免疫响应表达谱分析

Transcriptome analysis of immune responses of Plutella xylostella( Lepidoptera: Plutellidae ) infected by the entomopathogenic fungus Isaria fumosorosea

【目的】本研究旨在筛选小菜蛾Plutella xylostella应对玫烟色棒束孢Isaria fumosorosea侵染的免疫应答及其网络调控基因,以进一步探讨小菜蛾对玫烟色棒束孢的防御机制。【方法】采用第二代高通量测序技术RNA-seq,对处理后12 h的感染玫烟色棒束孢和健康(平行对照)的小菜蛾4龄幼虫转录组进行了测序,通过生物信息学分析对得到的差异基因进行了功能注释和分类,对差异基因参与的信号通路进行了分析。【结果】在感菌和健康小菜蛾幼虫转录组两个表达谱里,分别获得了12 346 987和12 315 210个clean reads,有60.93%和61.26%的reads分别能比对到参考基因库里,其中完美匹配(perfect match)的比例分别为32.15%和32.73%。共得到351个显著差异表达基因(differentially expressed unigenes,DEUs),上调表达基因有275个,下调表达基因有76个,与免疫防御反应潜在相关的基因有156个。GO(Gene Ontology)富集分析有102个DEUs分布到46个GO term里,KEGG(Kyoto Encyclopedia of Genes and Genomes)pathway富集分析结果显示,有132个DEUs显著富集在13个代谢通路(pathway)里。【结论】这些差异表达基因中,大部分编码潜在的与免疫识别及调控相关的基因,集中在能量代谢、疾病反应和防御反应等相关通路。研究结果为挖掘与玫烟色棒束孢侵染相关的小菜蛾免疫应答候选基因提供了重要数据库,也为阐明小菜蛾对玫烟色棒束孢的免疫机制奠定理论基础。

【Aim 】 This study aims to explore the immune-related genes and immune recognition regulatory network of Plutella xylostella against the entomopathogenic fungus Isaria fumosorosea,so to further investigate the innate immune mechanisms of P. xylostella to I. fumosorosea. 【Methods 】We analyzed the transcriptome of I. fumosorosea-infected and uninfected（ the control） 4th instar larvae of P.xylostella at 12 h after treatment using high-throughput single-end RNA-sequencing（ RNA-seq）. The differentially expressed genes and their functions,classifications and signaling pathways were analyzed using bioinformatic tools. 【Results】The numbers of 12 346 987 and 12 315 210 clean reads were obtained for the infected and uninfected libraries,respectively. Among the two RNA-seq libraries,60. 93% and61. 26% of reads could be mapped to reference genome with a perfect match proportion of 32. 15% and32. 73%,respectively. A total of 351 differentially expressed unigenes（ DEUs） were identified between infected and uninfected larvae. Among them,275 DEUs were up-regulated while 76 DEUs downregulated. In total,there were 156 DEUs putatively involved in immune responses. A Blast2 GO analysis indicated that 102 differentially expressed transcripts were able to be assigned to 46 Gene Ontology（ GO）terms. Kyoto Encyclopedia of Genes and Genomes（ KEGG） pathway enrichment analysis mapped 132 DEUs to 13 pathways（ P 0. 05）.【Conclusion】Most of the DEUs are putatively linked to innate immune recognition and regulation. These infection-responsive DEUs are enriched in various immune processes,such as energy metabolism,disease and defense response. The findings generated from this study provide a bioinformatic database for searching immune-related genes,and also benefit the future investigations of the innate immune mechanisms of P. xylostella against the entomopathogenic fungus I. fumosorosea.