Table1_Genome-wide identification and expression analysis of glutathione S-transferase gene family to reveal their role in cold stress response in cucumber.XLSX

The plant glutathione S-transferases (GSTs) are versatile proteins encoded by several genes and play vital roles in responding to various physiological processes. Members of plant GSTs have been identified in several species, but few studies on cucumber (Cucumis sativus L.) have been reported. In this study, we identified 46 GST genes, which were divided into 11 classes. Chromosomal location and genome mapping revealed that cucumber GSTs (CsGSTs) were unevenly distributed in seven chromosomes, and the syntenic regions differed in each chromosome. The conserved motifs and gene structure of CsGSTs were analyzed using MEME and GSDS 2.0 online tools, respectively. Transcriptome and RT-qPCR analysis revealed that most CsGST members responded to cold stress. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses for differentially expressed CsGSTs under cold stress revealed that these genes responded to cold stress probably through “glutathione metabolism.” Finally, we screened seven candidates that may be involved in cold stress using Venn analysis, and their promoters were analyzed using PlantCARE and New PLACE tools to predict the factors regulating these genes. Antioxidant enzyme activities were increased under cold stress conditions, which conferred tolerance against cold stress. Our study illustrates the characteristics and functions of CsGST genes, especially in responding to cold stress in cucumber.

植物谷胱甘肽S-转移酶（glutathione S-transferases, GSTs）是一类由多基因编码的多功能蛋白质，在响应多种生理过程中发挥关键作用。目前已有多个物种中鉴定出植物GST家族成员，但针对黄瓜（Cucumis sativus L.）的相关研究鲜有报道。本研究共鉴定得到46个GST基因，可分为11个亚类。染色体定位与基因组图谱分析显示，黄瓜GST基因（CsGSTs）在7条染色体上呈非均匀分布，且各染色体间的共线性区域存在差异。本研究分别利用MEME在线工具与GSDS 2.0在线工具分析了CsGSTs的保守基序与基因结构。转录组与逆转录实时定量PCR（RT-qPCR）分析结果表明，多数CsGST成员可响应低温胁迫。对低温胁迫下差异表达的CsGSTs进行基因本体（Gene Ontology, GO）与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）通路富集分析，结果显示这些基因可能通过"谷胱甘肽代谢"通路响应低温胁迫。最后，本研究通过维恩（Venn）分析筛选得到7个可能参与低温胁迫响应的候选基因，并利用PlantCARE与New PLACE工具对其启动子区域进行分析，以预测调控这些基因的转录因子。低温胁迫条件下抗氧化酶活性升高，从而赋予植株低温耐受能力。本研究阐明了黄瓜CsGST基因的特征与功能，特别是其在黄瓜低温胁迫响应中的作用。