生长素内流载体基因CkLAX3参与柠条锦鸡儿干旱胁迫响应的分析

植物干旱胁迫进程往往伴随着生长抑制类激素如脱落酸、乙烯的参与,而近年研究表明,生长素也可以响应干旱胁迫。本研究通过染色体步移、生信分析和亚细胞定位等方法,对CkLAX3基因在干旱响应中的作用进行了分析鉴定。研究经PCR扩增获得一个全长为1 398 bp的柠条生长素内流载体基因CkLAX3。生信分析发现,该序列编码465个氨基酸,分子量为52.47 kDa,其编码的蛋白为稳定的疏水性蛋白,二级结构主要由α螺旋组成,具有10重跨膜结构。亚细胞定位结果表明CkLAX3定位于细胞质膜。进化树分析结果表明,CkLAX3与红三叶、鹰嘴豆等植物LAX3基因亲缘关系较近。联合染色体步移和高效热不对称交错PCR (HiTail-PCR)方法克隆得到CkLAX3基因的未知启动子区序列总计1 352 bp。对启动子序列上的顺式作用元件进行分析发现,CkLAX3基因启动子区存在大量干旱响应元件、光响应元件、激素响应元件等。进一步对干旱处理的柠条锦鸡儿进行定量分析发现,CkLAX3的表达量受干旱胁迫诱导,推测该基因在干旱胁迫下发挥重要作用。本研究为进一步探索生长素在调节干旱胁迫应答过程中的作用机制提供了基础。

Analysis of Auxin Internal Flow Carrier Gene CkLAX3 Involved in Drought Stress Response of Caragana korshinskii

The process of drought stress in plants is often accompanied by the participation of growth inhibitory hormones such as abscisic acid and ethylene, recent studies have shown that auxin can also respond to drought stress. In this study, the role of CkLAX3 gene in drought response was analyzed and identified by means of genome walking, bioinformatics analysis and subcellular localization. A Caragana korshinskii auxin internal flow carrier gene CkLAX3 with the full length of 1 398 bp was obtained by PCR amplification. Bioinformatics analysis found that the sequence encodes 465 amino acids with a molecular weight of 52.47 kDa. The encoded protein is a stable hydrophobic protein. The secondary structure is mainly composed of α-helix and has a 10-fold transmembrane structure. The results of subcellular localization showed that CkLAX3 was located on the plasma membrane. Phylogenetic tree analysis showed that CkLAX3 was closely related to LAX3 genes in Trifolium pratense, Cicer arietinum and other plants. The length of unknown promoter region of CkLAX3 gene cloned by combining genome walking and HiTail-PCR was 1 352 bp. Based on the analysis of cis-acting elements in the promoter sequence, it was found that there were a large number of drought response elements, light response elements and hormone response elements in the promoter region of CkLAX3 gene. Further quantitative analysis of Caragana korshinskii treated with drought showed that the expression of CkLAX3 was induced by drought stress, and it was speculated that the gene played an important role under drought stress. This study provided a foundation for further investigating the regulation mechanisms of auxin in drought stress responses.