A Novel Wheat Nicotianamine Synthase Gene, TaNAS-D, Confers High Salt Tolerance in Transgenic Arabidopsis
A Novel Wheat Nicotianamine Synthase Gene, TaNAS-D, Confers High Salt Tolerance in Transgenic Arabidopsis
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新型小麦烟胺合酶基因 TaNAS-D 赋予转基因拟南芥高盐耐受性
DOI：
10.1007/s11105-016-1018-7
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发表时间：
2017-04-01
影响因子：
2.1
通讯作者：
Li, Junming
中科院分区：
文献类型：
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作者：
Han, Jie;Zhang, Wei;Li, Junming
烟胺合成酶(NAS)在平衡植物体内重金属浓度方面起着关键作用，但其在盐胁迫反应中的特征和功能还不完全清楚，特别是在小麦中。本研究从小麦中克隆了盐诱导基因Tanas-D，并对其进行了鉴定。Tanas-D定位于整个细胞，主要表达于发达的维管束组织中，对盐、ABA和H_2O_2胁迫有反应。Tanas-D在拟南芥中的过表达导致了NA水平的升高和耐盐性的增强，这表现在转Tanas-D基因的拟南芥植株在盐胁迫下的发芽率和生长速度都比WT好。进一步的研究表明，转Tanas-D基因拟南芥植株表现出较高的K+/Na+比，较低的丙二醛(MDA)水平和较低的离子渗漏(IL)，同时伴随着过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性的提高，从而减轻了膜伤害。此外，盐胁迫下Tanas-D的过表达增加了AtSOS1、AtSOS2、AtSOS3、AtFAD5和AtSAD1的转录水平。这些结果表明，Tanas-D通过改善抗氧化防御系统和上调盐过度敏感(SOS)途径基因而在耐盐性中发挥积极作用。
Nicotianamine synthase (NAS) plays a pivotal role in balancing the concentrations of heavy metals in plants, but its characteristics and functions in salt stress responses are not completely understood, particularly in wheat. In this study, the salt-induced gene TaNAS-D was cloned from wheat and characterized. TaNAS-D, localized throughout the cell, is mainly expressed in developed vascular bundle tissues and is responsive to NaCl, ABA, and H2O2 stresses. Overexpression of TaNAS-D in Arabidopsis led to elevated NA levels and enhanced salt stress tolerance, which was demonstrated by higher germination rates and improved growth of TaNAS-D transgenic Arabidopsis plants compared with WT when exposed to salt stress. Further investigation revealed that TaNAS-D transgenic Arabidopsis plants displayed higher K+/Na+ ratios, lower malondialdehyde (MDA) levels, and less ion leakage (IL) consistently accompanied by increased peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities, thereby reducing membrane injury. Moreover, TaNAS-D overexpression under salt stress increased AtSOS1, AtSOS2, AtSOS3, AtFAD5, and AtSAD1 transcript levels. These findings indicate that TaNAS-D plays a positive role in salt tolerance by improving the antioxidant defense system and upregulating salt overly sensitive (SOS) pathway genes.