College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
BMC Plant Biol. 2024 Oct 12;24(1):950. doi: 10.1186/s12870-024-05657-6.
Soil salinization is a serious environmental hazard, limiting plant growth and production in different agro-ecological zones worldwide. Diethyl aminoethyl hexanoate (DA-6) as an essential plant growth regulator (PGR) exhibits a beneficial role in improving crop growth and stress tolerance. However, the DA-6-regulated effect and mechanism of salt tolerance in plants are still not fully understood. The objective of current study was to disclose salt tolerance induced by DA-6 in relation to changes in water and redox balance, photosynthetic function, ionic homeostasis, and organic metabolites reprogramming in white clover (Trifolium repens).
A prolonged duration of salt stress caused water loss, impaired photosynthetic function, and oxidative injury to plants. However, foliar application of DA-6 significantly improved osmotic adjustment (OA), photochemical efficiency, and cell membrane stability under salt stress. In addition, high salinity induced massive accumulation of sodium (Na), but decreased accumulation of potassium (K) in leaves and roots of all plants. DA-6-treated plants demonstrated significantly higher transcript levels of genes involved in uptake and transport of Na and K such as VP1, HKT8, SOS1, NHX2, NHX6, and SKOR in leaves as well as VP1, HKT1, HKT8, H-ATPase, TPK5, SOS1, NHX2, and SKOR in roots. Metabolomics analysis further illustrated that DA-6 primarily induced the accumulation of glucuronic acid, hexanoic acid, linolenic acid, arachidonic acid, inosose, erythrulose, galactopyranose, talopyranose, urea, 1-monopalmitin, glycerol monostearate, campesterol, stigmasterol, and alanine.
The DA-6 significantly up-regulated transcript levels of multiple genes associated with increased Na compartmentalization in vacuoles and Na sequestration in roots to reduce Na transport to photosynthetic organs, thereby maintaining Na homeostasis under salt stress. The accumulation of many organic metabolites induced by the DA-6 could be attributed to enhanced cell wall and membrane structural stability and functionality, OA, antioxidant defense, and downstream signal transduction in leaves under salt stress. The present study provides a deep insight about the synergistic role of DA-6 in salt tolerance of white clover.
土壤盐渍化是一种严重的环境危害，限制了全球不同农业生态区的植物生长和生产。二乙氨基乙基己酸（DA-6）作为一种重要的植物生长调节剂（PGR），在提高作物生长和抗逆性方面表现出有益作用。然而，DA-6 对植物耐盐性的调节作用及其机制尚不完全清楚。本研究的目的是揭示 DA-6 诱导的耐盐性与水和氧化还原平衡、光合作用功能、离子稳态和有机代谢物重编程的变化有关，以白三叶草（Trifolium repens）为例。
盐胁迫时间延长会导致植物失水、光合作用功能受损和氧化损伤。然而，叶面喷施 DA-6 可显著提高盐胁迫下的渗透调节（OA）、光化学效率和细胞膜稳定性。此外，高盐诱导大量钠（Na）积累，但叶片和根中钾（K）积累减少。DA-6 处理的植物叶片中 VP1、HKT8、SOS1、NHX2、NHX6 和 SKOR 等 Na 和 K 吸收和转运相关基因的转录水平显著升高，根中 VP1、HKT1、HKT8、H-ATPase、TPK5、SOS1、NHX2 和 SKOR 等基因的转录水平也显著升高。代谢组学分析进一步表明，DA-6 主要诱导葡萄糖醛酸、己酸、亚麻酸、花生四烯酸、肌醇、赤藓糖、半乳糖吡喃糖、塔罗吡喃糖、尿素、1-单棕榈酸、甘油单硬脂酸酯、菜油甾醇、豆甾醇和丙氨酸的积累。
DA-6 显著上调与液泡中 Na 区室化和根中 Na 固定相关的多个基因的转录水平，从而减少 Na 向光合器官的运输，维持盐胁迫下的 Na 稳态。盐胁迫下叶片中许多有机代谢物的积累可能归因于细胞壁和膜结构稳定性和功能的增强、OA、抗氧化防御和下游信号转导。本研究深入了解了 DA-6 在白三叶草耐盐性中的协同作用。
