冬虫夏草菌芽生孢子体外及寄主蝠蛾血腔内发育的转录组分析

Transcriptome analyses of Ophiocordyceps sinensis blastospores developed in vitro and in hemocoel of host ghost moth

冬虫夏草菌Ophiocordyceps sinensis侵染寄主蝙蝠蛾后,两者的互作形成了一种非常独特的寄生系统。冬虫夏草菌侵入并成功定殖于寄主血腔是冬虫夏草人工抚育成功的关键。为探究冬虫夏草菌芽生孢子能够同小金蝠蛾Thitarodes xiaojinensis共存的原因,利用Illumina HiSeq 4000高通量测序平台,对体外人工液体培养的冬虫夏草菌芽生孢子和寄主蝠蛾血腔内的芽生孢子进行转录组测序。基于差异倍数(foldchange)和错误发现率(FDR)筛选差异表达基因,具体筛选条件为|Log2(fold change)|≥1、FDR≤0.05,共获得2298个差异表达基因,其中上调表达基因1162个,下调表达基因1136个。基因本体(GO)数据库和京都基因与基因组百科全书(KEGG)富集分析结果显示,差异表达基因主要富集于基础代谢活动和信号转导等。进一步分析发现,生长于寄主血腔内的芽生孢子细胞壁的相关基因和糖苷水解酶、热激蛋白、LysM等基因显著上调表达,暗示冬虫夏草菌通过改变细胞壁结构、提高氧化应激保护能力等方式来适应寄主血腔内的环境。本研究通过高通量测序技术和生物信息分析等手段,获得了冬虫夏草菌在体外和寄主血腔内的转录组信息特征,为阐明冬虫夏草菌芽生孢子适应小金蝠蛾血腔内环境并正常发育的机制提供参考。

Ophiocordyceps sinensis infected ghost moth,forming a unique parasitic system.Successful artificial cultivation of Chinese cordyceps depends on successful invasion and colonization of the fungus in host hemocoel.To understand the mechanism of coexistence between O.sinensis blastospores and the host Thitarodes xiaojinensis,high-throughput illumina HiSeq system was used to analyze the transcriptome data of the blastospores formed in vitro(IV)in a liquid medium and developed in host hemocoel at proliferative stage(BP).Differentially expressed genes(DEGs)were obtained under the screening conditions of|Log2(fold change)|≥1 and FDR≤0.05.In total,2298 DEGs were obtained,including 1162 upregulated genes and 1136 downregulated genes.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis showed that these DEGs were mainly involved in metabolic activity and signal transduction.Further analysis revealed that genes related to the cell wall,glycoside hydrolases,heat shock proteins and LysM protein were significantly upregulated in BP,suggesting that O.sinensis could adapt itself to the host hemocoel environment by changing the cell wall structure and improving the oxidative stress protection capacity.In this study,the transcriptomic information characteristics of O.sinensis blastospores cultured in vitro and in vivo were revealed by means of high-throughput sequencing technology and bioinformatics analysis,providing a reference for clarifying the mechanism of O.sinensis blastospores adapting to the host hemocoel environment and developing within the host hemocoel.