红树植物秋茄查尔酮合酶基因克隆及其在盐胁迫下的表达分析

以秋茄(Kandelia candel)叶片为试验材料,采用RT-PCR的方法获得秋茄查尔酮合酶(chalcone synthase,CHS)基因的cDNA序列,命名为KcCHS,GenBank登录号为KX673194.1.序列分析结果表明,KcCHS基因的cDNA序列长度为1170bp,编码389个氨基酸,属于CHS超家族.序列比对结果显示,秋茄与其他物种的CHS基因核苷酸序列具有较高的相似性,平均达到80%以上.系统进化分析显示,KcCHS基因与余甘子CHS基因亲缘关系最近.实时荧光定量PCR分析表明,秋茄叶片KcCHS基因的转录水平随着NaCl浓度的升高而上升.此外,随着NaCl浓度的升高,黄酮类化合物的含量显著增加,羟自由基清除率也明显提高.

Cloning and expression analysis of chalcone synthase gene from mangrove tree Kandelia candel under salt stress

The accumulation of flavonoid plays an important role in physiological accommodation when Kandelia candel suffered from high-salinity stress. In this study, a cDNA sequence of chalcone synthase (CHS) gene from the leaves of K.candel was cloned using RT-PCR, named KcCHS (GenBank accession. KX673194.1). Sequence analysis indicated that the cDNA sequence of KcCHS contained an open reading frame (ORF) of 1170 bp encoding 389 amino acids which belonged to the CHS superfamily. Sequence alignment analysis revealed that CHS from K.candel shared more than 80% homology with CHS from other plant species. The phylogenetic analysis based on the cDNA sequences showed that KcCHS had the closest genetic relationship with the CHS from Phyllanthus emblica. Real-time quantitative PCR was carried out to analyze the expression level of KcCHS under different NaCl conditions, showing that its expression level increased with elevated NaCl concentration. Furthermore, the content of flavonoids and the scavenging rate of hydroxyl radical in NaCl treatments both increased compared with the control. These results suggested that the up-regulation expression of KcCHS might improve salt tolerance of K.candel.