马铃薯StGS基因克隆及镉胁迫下的表达分析

Cloning and Expression Analysis of StGS Gene of Potato(Solanum tuberosum)under Cadmium Stress

谷胱甘肽(glutathione, GSH)是植物体内重要的抗氧化剂,能有效清除活性氧自由基对细胞造成的损伤。为研究镉胁迫对马铃薯(Solanum tuberosum)谷胱甘肽合成酶(glutathione synthetase, GS)编码基因表达的影响,本研究以马铃薯‘威芋7号’为试验材料,采用同源克隆的方法从cDNA中克隆到StGS基因。序列分析表明,该基因ORF全长为1 644 bp,可编码344个氨基酸;在所选的物种中,蛋白序列同源性分析显示,马铃薯GS蛋白与潘那利番茄(Solanum pennellii)的亲缘关系最近,相似度为93.98%,与枸杞(Lycium barbarum)亲缘关系最远。另外,实时荧光定量PCR分析表明,镉胁迫24 h与4 h相比,马铃薯根和叶中GS相对表达量均达到极显著水平,分别为胁迫4 h的15倍和13倍;而在茎中GS相对表达量呈现出下降趋势。镉胁迫4 h时GS相对表达量为24 h的6倍,暗示StGS不仅是一个镉应答的基因,而且马铃薯植株不同器官应在应答镉胁迫时GS的表达存在一定差异。本研究结果为进一步探究StGS基因介导的镉胁迫响应机制提供前期基础。

Glutathione(GSH)is an important antioxidant in plants,which can effectively remove the damage caused by reactive oxygen radicals to cells.In order to study the effect of cadmium stress on the expression of the gene encoding glutathione synthetase(GS)of potato(Solanum tuberosum),this research used potato’Weiyu 7’as the test material and adopted the method of homologous cloning from cDNA Clone into the StGS gene.Sequence analysis showed that the full-length ORF of this gene was 1644 bp,which could encode 344 amino acids;protein sequence homology analysis showed that S.tuberosum GS protein had the closest relationship with Solanum pennellii with a similarity of 93.98%,and has the farthest relationship with Lycium barbarum.In addition,quantitative real-time PCR analysis showed that at 24 h after cadmium stress,the relative expression of GS gene in potato roots and leaves reached highly significant levels,which were 15 times and 13 times of 4 h of stress,respectively,while the relative expression of GS gene in the stem showed a downward trend.The relative expression of GS gene at 4 h of cadmium stress was 6 times that of 24 h,suggesting that StGS is not only a cadmium-responsive gene,but also differently expressed in various organs of potato plants in response to cadmium stress.This results provides an early basis for further exploring the mechanism of StGS gene-mediated response to cadmium stress.