Wang Pengju, Xu Zijian, Zhang Yong, Ma Yongbo, Yang Jianyu, Zhou Fan, Gao Yi, Li Guobin, Hu Xiaohui
College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China; Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling, Shaanxi, 712100, China; Shaanxi Protected Agriculture Research Centre, Yangling, Shaanxi, 712100, China.
College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China; Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling, Shaanxi, 712100, China; Shaanxi Protected Agriculture Research Centre, Yangling, Shaanxi, 712100, China.
Plant Physiol Biochem. 2022 Dec 1;192:172-185. doi: 10.1016/j.plaphy.2022.09.025. Epub 2022 Oct 3.
Endogenous spermidine can improve the resistance of plants to saline-alkali stress. SlSPDS1 and SlSPDS2 are the main spermidine synthase (SPDS) genes in tomatoes. In comparison with SlSPDS1, SlSPDS2 plays an important role in wild-type tomato seedling under saline-alkali stress. However, limited research has focused on the role of SlSPDS2 in saline-alkali stress. Wild-type (WT) and SPDS gene (SlSPDS2) transgenic over-expression tomato seedlings were used to explore the function of endogenous spermidine on the saline-alkali resistance of tomato seedlings. The results show that SlSPDS2 overexpression under normal conditions and saline-alkali stress increased the content of endogenous free polyamines and the expression levels of polyamine synthesis-related genes in tomato seedlings. Under saline-alkali stress, SlSPDS2 overexpression significantly reduced Na/K ratio, relative electrical conductivity, O, HO, and malondialdehyde content, increased Seedling index, relative water content, antioxidant enzyme activities (peroxidase, superoxide dismutase, and catalase), and the contents of proline and soluble sugar in tomato leaf, and mitigated the adverse effect of saline-alkali stress on tomato seedlings. In summary, the overexpression of SlSPDS2 tomato seedlings regulated the ionic homeostasis, antioxidant enzyme system, and osmotic regulatory substances of tomato seedlings living in saline-alkali environment by increasing endogenous free polyamine content, thereby improving the resistance of tomato seedlings against saline-alkali stress.
内源性亚精胺可以提高植物对盐碱胁迫的抗性。SlSPDS1和SlSPDS2是番茄中主要的亚精胺合酶（SPDS）基因。与SlSPDS1相比，SlSPDS2在盐碱胁迫下的野生型番茄幼苗中发挥重要作用。然而，针对SlSPDS2在盐碱胁迫中作用的研究有限。本研究利用野生型（WT）和SPDS基因（SlSPDS2）转基因过表达番茄幼苗，探究内源性亚精胺对番茄幼苗耐盐碱能力的影响。结果表明，正常条件和盐碱胁迫下SlSPDS2过表达均提高了番茄幼苗内源性游离多胺含量及多胺合成相关基因的表达水平。在盐碱胁迫下，SlSPDS2过表达显著降低了番茄叶片的Na/K比、相对电导率、O、HO和丙二醛含量，提高了幼苗指数、相对含水量、抗氧化酶活性（过氧化物酶、超氧化物歧化酶和过氧化氢酶）以及脯氨酸和可溶性糖含量，减轻了盐碱胁迫对番茄幼苗的不利影响。综上所述，SlSPDS2过表达番茄幼苗通过增加内源性游离多胺含量，调节了盐碱环境中番茄幼苗的离子稳态、抗氧化酶系统和渗透调节物质，从而提高了番茄幼苗对盐碱胁迫的抗性。
