Ma Chunquan, Wang Yuguang, Gu Dan, Nan Jingdong, Chen Sixue, Li Haiying
Key Laboratory of Molecular Biology, College of Heilongjiang Province, College of Life Sciences, Heilongjiang University, Harbin 150080, China.
Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150080, China.
Int J Mol Sci. 2017 Apr 18;18(4):847. doi: 10.3390/ijms18040847.
The sugar beet monosomic addition line M14 is a unique germplasm that contains genetic materials from L. and Zoss, and shows tolerance to salt stress. Our study focuses on exploring the molecular mechanism of the salt tolerance of the sugar beet M14. In order to identify differentially expressed genes in M14 under salt stress, a subtractive cDNA library was generated by suppression subtractive hybridization (SSH). A total of 36 unique sequences were identified in the library and their putative functions were analyzed. One of the genes, -adenosylmethionine synthetase (), is the key enzyme involved in the biosynthesis of -adenosylmethionine (SAM), a precursor of polyamines. To determine the potential role of in salt tolerance, we isolated from the salt-tolerant sugar beet M14. The expression of in leaves and roots was greatly induced by salt stress. Overexpression of in resulted in enhanced salt and H₂O₂ tolerance. Furthermore, we obtained a knock-down T-DNA insertion mutant of , which shares the highest homology with . Interestingly, the mutant showed sensitivity to salt and H₂O₂ stress. We also found that the antioxidant system and polyamine metabolism play an important role in salt and H₂O₂ tolerance in the -overexpressed plants. To our knowledge, the function of the sugar beet SAMS has not been reported before. Our results have provided new insights into SAMS functions in sugar beet.
甜菜单体附加系M14是一种独特的种质资源，含有来自L.和Zoss的遗传物质，对盐胁迫具有耐受性。我们的研究重点是探索甜菜M14耐盐性的分子机制。为了鉴定盐胁迫下M14中差异表达的基因，通过抑制性消减杂交（SSH）构建了一个消减cDNA文库。在文库中总共鉴定出36个独特序列，并对其推定功能进行了分析。其中一个基因，S-腺苷甲硫氨酸合成酶（SAMS），是参与多胺前体S-腺苷甲硫氨酸（SAM）生物合成的关键酶。为了确定SAMS在耐盐性中的潜在作用，我们从耐盐甜菜M14中分离出SAMS。盐胁迫极大地诱导了SAMS在叶片和根中的表达。在拟南芥中过表达SAMS导致对盐和H₂O₂耐受性增强。此外，我们获得了与SAMS具有最高同源性的SAMS的T-DNA插入敲除突变体。有趣的是，突变体sams对盐和H₂O₂胁迫表现出敏感性。我们还发现抗氧化系统和多胺代谢在过表达SAMS的植物的盐和H₂O₂耐受性中起重要作用。据我们所知，甜菜SAMS的功能以前尚未见报道。我们的结果为甜菜中SAMS的功能提供了新的见解。
