黄瓜肌醇半乳糖苷合成酶基因GolS2克隆与表达调控

Cloning and Expression Regulation of Cucumber Inositol Galactinol Synthase Gene GolS2

肌醇半乳糖苷合成酶(GolS)是合成棉子糖系列寡糖(RFOs)的关键酶,在植物抵抗非生物胁迫过程中发挥重要作用。为探究GolS2基因在黄瓜应答非生物胁迫中的作用,本研究采用RT-PCR法从黄瓜中克隆了GolS2基因,其开放阅读框长度为981 bp,编码326个氨基酸,植物GolS2蛋白氨基酸序列一致性很高。进化树中,黄瓜GolS2蛋白与拟南芥GolS2和GolS3蛋白聚在同一分支,亲缘关系最近。盐胁迫和低温胁迫处理显著诱导GolS2基因在黄瓜幼苗中的表达,但低温处理显著抑制GolS2基因在采后黄瓜果实中的表达。对其启动子顺式作用元件的分析结果显示,GolS2基因启动子中含有多个与逆境胁迫响应有关的顺式作用元件。在采后黄瓜果实中沉默HHO2和GRP3基因的表达,显著下调GolS2基因表达,表明这两个基因调控GolS2基因表达。本研究结果明确了GolS2基因在不同类型黄瓜组织中应答非生物胁迫的功能存在差异,这为进一步研究该基因的功能奠定了基础。

Inositol galactinol synthase(GolS)is a key enzyme in the biosynthesis of raffinose family oli-gosaccharides(RFOs),which plays an important role in the process of plant resistant to abiotic stress.In or-der to explore the role of GolS2 gene in cucumber response to abiotic stresses,the GolS2 gene was cloned from cucumber by RT-PCR method.Its open reading frame length was 981 bp,and it encoded 326 amino acids.The amino acid sequence of plant GolS2 protein was highly consistent with each other.In the phylogenetic tree,cu-cumber GolS2 protein and Arabidopsis GolS2 and GolS3 proteins were clustered into one branch,suggesting that the genetic relationship should be the closest.Salt stress and low-temperature stress significantly induced GolS2 gene expression in cucumber seedlings,but low-temperature treatment significantly inhibited GolS2 gene expression in postharvest cucumber fruits.The analysis of cis-element in GolS2 promoter showed that there were several cis-elements related to stress response.In harvested cucumber fruits,the silencing of HHO2 and GRP3 genes significantly down-regulated GolS2 gene expression,indicating that these two genes regulated GolS2 gene expression in cucumber.The results of this study confirmed the role difference of GolS2 gene in re-sponse to abiotic stresses in different types of cucumber tissues,which laid a foundation for further study on GolS2 gene roles.