Overexpression of a S-Adenosylmethionine Decarboxylase from Sugar Beet M14 Increased Araidopsis Salt Tolerance
Overexpression of a S-Adenosylmethionine Decarboxylase from Sugar Beet M14 Increased Araidopsis Salt Tolerance
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甜菜 M14 中 S-腺苷甲硫氨酸脱羧酶的过度表达增加了拟南芥的耐盐性
DOI：
10.3390/ijms20081990
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发表时间：
2019-04-02
影响因子：
5.6
通讯作者：
Wang, Yuguang
中科院分区：
文献类型：
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作者：
Ji, Meichao;Wang, Kun;Wang, Yuguang
多胺在植物的生长发育和对非生物胁迫的响应中起着重要作用。以前，差异表达的蛋白质在甜菜M14（BvM 14）在盐胁迫下，确定了iTRAQ为基础的定量蛋白质组学。其中一种蛋白质是S-腺苷甲硫氨酸脱羧酶（SAMDC），这是一种参与多胺生物合成的关键限速酶。本研究从甜菜M14中克隆了BvM 14-SAMDC基因。BvM 14-SAMDC全长1960 bp，开放阅读框（ORF）为1119 bp，编码372个氨基酸。此外，我们在大肠杆菌中表达了BvM 14-SAMDC的编码序列，并纯化了具有高酶活性的约40 kD的BvM 14-SAMDC。实时荧光定量PCR分析表明，盐胁迫下BvM 14-SAMDC在BvM 14根和叶中表达上调。为了研究BvM 14-SAMDC的功能，将其在拟南芥中组成型表达。转基因植株表现出更强的耐盐性，表现为在盐处理下比野生型（WT）更长的根长、更高的鲜重和叶绿素含量。与野生型相比，转基因植株的精脒（Spd）和精蛋白（Spm）含量增加。此外，过表达植株表现出更高的抗氧化酶活性和降低细胞膜损伤。与WT相比，它们也具有低表达水平的RbohD和RbohF，其参与活性氧（ROS）的产生。总之，这些结果表明BvM 14-SAMDC介导的Spm和Spd的生物合成通过增强抗氧化酶和减少ROS产生而有助于植物耐盐胁迫。
Polyamines play an important role in plant growth and development, and response to abiotic stresses. Previously, differentially expressed proteins in sugar beet M14 (BvM14) under salt stress were identified by iTRAQ-based quantitative proteomics. One of the proteins was an S-adenosylmethionine decarboxylase (SAMDC), a key rate-limiting enzyme involved in the biosynthesis of polyamines. In this study, the BvM14-SAMDC gene was cloned from the sugar beet M14. The full-length BvM14-SAMDC was 1960 bp, and its ORF contained 1119 bp encoding the SAMDC of 372 amino acids. In addition, we expressed the coding sequence of BvM14-SAMDC in Escherichia coli and purified the ~40 kD BvM14-SAMDC with high enzymatic activity. Quantitative real-time PCR analysis revealed that the BvM14-SAMDC was up-regulated in the BvM14 roots and leaves under salt stress. To investigate the functions of the BvM14-SAMDC, it was constitutively expressed in Arabidopsis thaliana. The transgenic plants exhibited greater salt stress tolerance, as evidenced by longer root length and higher fresh weight and chlorophyll content than wild type (WT) under salt treatment. The levels of spermidine (Spd) and spermin (Spm) concentrations were increased in the transgenic plants as compared with the WT. Furthermore, the overexpression plants showed higher activities of antioxidant enzymes and decreased cell membrane damage. Compared with WT, they also had low expression levels of RbohD and RbohF, which are involved in reactive oxygen species (ROS) production. Together, these results suggest that the BvM14-SAMDC mediated biosynthesis of Spm and Spd contributes to plant salt stress tolerance through enhancing antioxidant enzymes and decreasing ROS generation.