根瘤菌侵染早期大豆根系的转录组分析

Transcriptome Analysis of Soybean Root System in the Early Stage of Rhizobium Infection

为了解析共生早期根瘤菌与宿主植物根组织信号交互调控作用,深入了解根瘤菌侵染早期根系的基因调控网络以及进一步解析豆科植物如何进化形成与根瘤菌共生的分子机制,本研究对根瘤菌侵染12 h后大豆的根组织材料进行转录组测序分析,对受显著调控的基因进行GO和KEGG显著性富集分析,采用qRT-PCR方法验证候选基因的表达情况,并通过构建进化树和绘制表达聚类图分析候选基因的进化及功能特征。研究共鉴定出488个在共生早期受根瘤菌侵染显著调控的基因。GO富集结果显示,上调基因中富集了参与损伤应答功能的基因,而下调基因的功能主要富集在细胞壁生物合成调控途径。KEGG通路富集分析显示,参与植物与病菌互作、植物激素转导和MAPK信号通路的基因在上调基因中富集,而编码ABC转运蛋白以及植物节律相关的蛋白基因在下调基因中富集。其中对损伤应答富集基因的分析鉴定出可能在大豆中参与根瘤菌侵染早期调控的损伤诱导短肽(Wound-Induced Peptide,WIP)家族。转录组和qRT-PCR结果显示16个WIP基因在根瘤菌侵染后受到不同程度的诱导表达。对大豆WIP家族基因序列的进化分析结果以及表达聚类分析结果均显示,受根瘤菌诱导表达的WIP基因亚家族的序列和表达均表现出与拟南芥同源的WIP基因亚家族不同的特性。

To analyze signal regulation between rhizobia and host plant in symbiosis,understand gene regulation network of the root system in the early stage of rhizobial infection,and explore the molecular mechanism of evolution of legume symbiosis,the transcriptomic profiles were performed from soybean root tissues infected by rhizobia for 12 h.The significantly regulated genes were analyzed by gene ontology(GO)and KEGG pathway enrichment analysis,the expression of candidate genes in the pathway were verified by qRT-PCR,and evolutionary and functional features of candidate genes were analyzed by phylogenetic tree and correlation cluster analysis.In this research,a total of 488 genes were identified which were significantly regulated by rhizobial infection in the early stage of symbiosis.GO enrichment analysis showed that the up-regulated genes were enriched in wounding response,while the down-regulated genes were enriched in regulation of cell wall biosynthesis.KEGG pathway enrichment analysis showed that the genes involved in plant-pathogen interaction,plant hormone transduction and MAPK signaling pathway were enriched in up-regulated genes,while the genes encoding ABC transporter and circadian rhythm were enriched in down-regulated genes.The analysis of genes enriched in wounding response identified the WIP(Wound-Induced Peptide)family that may be involved in regulation of rhizobia infection in soybeans.RNA-seq and qRT-PCR results showed that 16 WIP genes were induced after rhizobial infection.Molecular evolutionary analysis and gene expression cluster analysis showed that the sequence and expression feature of WIP subfamilies which induced by rhizobia were different from WIP subfamily homologous to Arabidopsis thaliana.