中文摘要：

红树植物杯萼海桑是最耐盐的红树植物之一。S-腺苷甲硫氨酸合成酶（S-adenosylmethionine synthetase,SAMS）是S-腺苷甲硫氨酸（S-adenosylmethionine,SAM）生物合成途径的关键酶。SAMS作为一个逆境胁迫响应蛋白在植物的耐盐调控中发挥着极其重要的作用。本文结合杯萼海桑根的转录组注释,根据编码区序列设计引物,通过PCR克隆杯萼海桑SAMS基因的编码区cDNA,并对其进行生物信息分析,为研究杯萼海桑适应逆境的机制奠定理论基础。结果显示PCR扩增了一个长1 182 bp的基因片段,该片段编码由393个氨基酸组成的S-腺苷甲硫氨酸合成酶。同源性比对及进化树分析显示杯萼海桑的SAMS氨基酸序列进化上相对保守。本研究首次从红树林植物杯萼海桑中克隆S-腺苷甲硫氨酸合成酶基因,并获得其编码区序列,为进一步研究杯萼海桑应对逆境胁迫的分子生物学机制与胁迫相关基因调控网络奠定基础。

英文摘要：

Sonneratia alba is one of the most salt-tolerant mangroves. S-adenosylmethionine synthetase（ SAMS） which was in response to abiotic stresses played an important role in salt tolerance. In order to study the biological mechanism of S. alba for adapting stress,the coding region of SaSAMS gene which codes a key enzyme in the S-adenosylmethionine（ SAM） biosynthetic pathway was isolated. Based on the annotation of root transcriptome of S. alba,primers was designed and cDNA of SaSAMS gene was amplified by PCR. The complete coding sequence of SaSAMS gene was 1 182 bp and it encoded a protein of 393 amino acids. Homology comparison and evolutionary tree analysis showed that the SAMS amino acid sequences were relatively conserved in plants. The SaSAMS gene was cloned from a mangrove tree S. alba for the first time and this would facilitate further investigation on molecular mechanism of stress tolerance and regulation networks of stress-related genes in S. alba.