College of Grassland Agriculture, Northwest A&F University, Yangling, Xianyang 712100, China.
Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China.
Genes (Basel). 2022 Nov 2;13(11):2004. doi: 10.3390/genes13112004.
(1) Background: Alfalfa is an important legume forage throughout the world. Although alfalfa is considered moderately tolerant to salinity, its production and nitrogen-fixing activity are greatly limited by salt stress. (2) Methods: We examined the physiological changes and proteomic profiles of alfalfa with active nodules (NA) and without nodules (NN) under NaCl treatment. (3) Results: Our data suggested that NA roots showed upregulation of the pathways of abiotic and biotic stress responses (e.g., heat shock proteins and pathogenesis-related proteins), antioxidant enzyme synthesis, protein synthesis and degradation, cell wall degradation and modification, acid phosphatases, and porin transport when compared with NN plants under salt stress conditions. NA roots also upregulated the processes or proteins of lipid metabolism, heat shock proteins, protein degradation and folding, and cell cytoskeleton, downregulated the DNA and protein synthesis process, and vacuolar H-ATPase proteins under salt stress. Besides, NA roots displayed a net H influx and low level of K efflux under salt stress, which may enhance the salt tolerance of NA plants. (4) Conclusions: The symbiosis conferred the host plant salt tolerance by regulating a series of physiological processes to enhance stress response, improve antioxidant ability and energy use efficiency, and maintain ion homeostasis.
（1）背景：紫花苜蓿是全世界重要的豆科牧草。尽管紫花苜蓿被认为对盐度具有中度耐受性，但盐胁迫极大地限制了其生产和固氮活性。（2）方法：我们研究了在 NaCl 处理下具有活跃根瘤（NA）和无根瘤（NN）的紫花苜蓿的生理变化和蛋白质组谱。（3）结果：与盐胁迫条件下的 NN 植物相比，我们的数据表明，NA 根在非生物和生物胁迫响应途径（例如热休克蛋白和病程相关蛋白）、抗氧化酶合成、蛋白质合成和降解、细胞壁降解和修饰、酸性磷酸酶和孔道蛋白转运方面表现出上调。NA 根在盐胁迫下还上调了脂质代谢、热休克蛋白、蛋白质降解和折叠以及细胞骨架的过程或蛋白质，下调了 DNA 和蛋白质合成过程以及液泡 H+-ATP 酶蛋白。此外，NA 根在盐胁迫下表现出净 H+流入和低钾流出，这可能增强了 NA 植物的耐盐性。（4）结论：共生通过调节一系列生理过程赋予宿主植物耐盐性，以增强应激反应、提高抗氧化能力和能量利用效率，并维持离子稳态。
