外源NO缓解草地早熟禾镉胁迫的转录组分析

Transcriptome Analysis of Exogenous Nitric oxide on Alleviating Cadmium Stress in Kentucky Bluegrass

为揭示外源一氧化氮对草地早熟禾(Poa pratensis)镉(Cadmium,Cd)胁迫缓解机制,本试验采用高通量Illumina Hiseq测序技术研究了草地早熟禾根施1000μmol·L-1氯化镉和叶面喷施50μmol·L-1 NO供体硝普钠24 h后转录组基因的差异表达。对测序数据进行分析结果显示,4个处理组共有22730个差异表达基因,包括15332个上调基因和7398个下调基因。通过富集分析发现外源NO主要通过调控与信号转导、碳水化合物转运与代谢、氨基酸生物合成及苯丙烷生物合成等途径相关的基因缓解镉胁迫。此外,本研究对Cd处理与Cd+NO处理组的差异表达基因和代谢通路进行分析,筛选出了一系列由NO信号介导的草地早熟禾响应镉胁迫关键基因,并将其列为NO缓解草地早熟禾镉胁迫相关的候选基因。本研究为挖掘草地早熟禾耐镉相关调控基因和功能基因提供基础。

In order to reveal the mechanism of exogenous nitric oxide(NO) relieving the cadmium stress on Kentucky bluegrass(Poa pratensis),high-throughput Illumina Hiseq sequencing technique was applied to study the expression of transcriptomes in Kentucky Bluegrass treated with 1000 μmol·L-1 CdCl2(Cadmium chloride hemidihydrate,CdCl2·2.5 H2O) and 50 μmol·L-1 NO donor sodium nitrate(SNP) for 24 h. The samples were divided into 4 treatment groups for transcriptome sequencing,namely the CK control group,NO treatment group,Cd stress treatment group,and Cd + NO treatment group. The analysis of the sequencing data showed that there were 22 730 differentially expressed genes,including 15 332 up-regulated genes and 7 398 down-regulated genes. Through enrichment analysis,it was found that exogenous NO alleviated cadmium stress mainly by regulating signal transduction genes related to carbohydrate transport and metabolic amino acid biosynthesis and phenylpropane biosynthesis. In addition,the differentially expressed genes and metabolic pathways between Cd and Cd + NO treatment groups were analyzed to screen out key genes mediated by NO signal in response to cadmium stress. At the same time,these genes were also selected as candidate genes for NO to alleviate cadmium stress of Kentucky bluegrass. This study provides a basis for further exploration of Cd-related regulatory genes and functional genes of Kentucky bluegrass.