Ectopic expression of CsTGase enhances salt tolerance by regulating polyamine biosynthesis, antioxidant activities and Na+/K+ homeostasis in transgenic tobacco
Ectopic expression of CsTGase enhances salt tolerance by regulating polyamine biosynthesis, antioxidant activities and Na+/K+ homeostasis in transgenic tobacco
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CsTGase 的异位表达通过调节转基因烟草中的多胺生物合成、抗氧化活性和 Na /K 稳态来增强耐盐性
DOI：
10.1016/j.plantsci.2020.110492
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发表时间：
2020
期刊：
影响因子：
5.2
通讯作者：
Guo Shirong
中科院分区：
文献类型：
--
作者：
Zhong Min;Wang Yu;Shu Sheng;Sun Jin;Guo Shirong
转谷氨酰胺酶 (TGase) 是多胺 (PA) 特定蛋白质转酰胺基作用的介质，在动物 PA 代谢中发挥着关键作用，但其功能和调节机制在植物中很大程度上未知。在本研究中，我们证明了黄瓜中的 TGase 在盐胁迫下调节 PA 代谢中发挥保护作用。黄瓜中盐胁迫诱导TGase的表达。基于外部症状和膜完整性，黄瓜TGase在烟草中的异位过度表达增强了对盐胁迫的耐受性。过表达株系在盐胁迫下维持高水平的PAs，表明PAs在TGase诱导的耐盐性中发挥着至关重要的作用。相反，野生型（WT）植物中Na+含量水平增加，而过表达植物中Na+含量水平降低。盐胁迫下，一些与离子交换相关的基因的表达水平增强，并且由于TGase活性增加，Na+/K+比率降低。盐胁迫下过表达株系中质子泵ATP酶（H+-ATP酶）、液泡H+-ATP酶（V-ATP酶）和液泡H+-焦磷酸酶（PPase）的活性高于WT植物。此外，过表达株系中的丙二醛（MDA）和H2O2含量显着低于WT植物，同时抗氧化酶活性增加。综上所述，这些研究结果表明，TGase 在响应盐胁迫方面发挥保护作用，可能通过调节盐胁迫下的 PA 代谢和 Na+/K+ 平衡来促进植物存活。
Transglutaminases (TGases), mediators of the transamidation of specific proteins by polyamines (PA), play critical roles in PA metabolism in animals, but their functions and regulatory mechanisms are largely unknown in plants. In this study, we demonstrated that TGase from cucumber played a protective role in the regulation of PA metabolism under salt stress. The expression ofTGasewas induced by salt stress in cucumber. Ectopic overexpression of cucumberTGasein tobacco conferred enhanced tolerance to salt stress based on both external symptoms and membrane integrity. Overexpression lines maintained high levels of PAs under salt stress, suggesting that PAs played a vital role inTGase-induced salt tolerance. In contrast, the levels of Na+content in the wild-type (WT) plants increased, while they decreased in the overexpression plants. The expression levels of several genes related to ion exchange enhanced, and the Na+/K+ratio decreased by increased TGase activity under salt stress. The activities of the proton-pump ATPase (H+-ATPase), vacuolar H+-ATPase (V-ATPase) and vacuolar H+-pyrophosphatase (PPase) were higher in the overexpression lines than in WT plants under salt stress. Moreover, the malondialdehyde (MDA) and H2O2contents were significantly lower in the overexpression lines than in WT plants, accompanied by increased antioxidant enzyme activity. Taken together, these findings demonstrate that TGase plays protective roles in response to salt stress, which may promote plant survival by regulating PA metabolism and the Na+/K+balance under salt stress.