State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China.
China Fukang Station of Desert Ecology, Chinese Academy of Sciences, Fukang, 831505, Xinjiang, China.
BMC Plant Biol. 2022 Nov 30;22(1):552. doi: 10.1186/s12870-022-03930-0.
Salinization is major abiotic stress limiting cotton production. Melatonin (MT) has been implicated in salt stress tolerance in multiple crops including upland cotton. Here, we explored the transcriptomic and metabolomic response of a salt-tolerant self-bred high-yielding cotton line SDS-01, which was exogenously sprayed with four MT concentrations (50, 100, 200, and 500 μM).
Here we found that MT improves plant biomass and growth under salt stress. The combined transcriptome sequencing and metabolome profiling approach revealed that photosynthetic efficiency is improved by increasing the expressions of chlorophyll metabolism and antenna proteins in MT-treated seedlings. Additionally, linoleic acid and flavonoid biosynthesis were improved after MT treatment. The Na/K homeostasis-related genes were increasingly expressed in salt-stressed seedlings treated with MT as compared to the ones experiencing only salt stress. Melatonin treatment activated a cascade of plant-hormone signal transduction and reactive oxygen scavenging genes to alleviate the detrimental effects of salt stress. The global metabolome profile revealed an increased accumulation of flavonoids, organic acids, amino acids and derivatives, saccharides, and phenolic acids in MT-treated seedlings. Interestingly, N, N'-Diferuloylputrescine a known antioxidative compound was highly accumulated after MT treatment.
Collectively, our study concludes that MT is a salt stress regulator in upland cotton and alleviates salt-stress effects by modulating the expressions of photosynthesis (and related pathways), flavonoid, ROS scavenging, hormone signaling, linoleic acid metabolism, and ion homeostasis-related genes.
盐渍化是限制棉花生产的主要非生物胁迫。褪黑素（MT）已被牵涉到多种作物包括陆地棉的耐盐胁迫中。在这里，我们研究了耐盐自育高产棉花品系 SDS-01 的转录组和代谢组对盐胁迫的响应，该品系经外源喷洒四种 MT 浓度（50、100、200 和 500μM）。
我们发现 MT 可改善盐胁迫下的植物生物量和生长。结合转录组测序和代谢组分析方法，发现 MT 处理可提高叶绿素代谢和天线蛋白的表达，从而提高光合作用效率。此外，MT 处理后亚油酸和类黄酮生物合成得到改善。与仅经历盐胁迫的幼苗相比，经 MT 处理的盐胁迫幼苗中与 Na/K 稳态相关的基因表达增加。褪黑素处理激活了植物激素信号转导和活性氧清除基因的级联反应，以减轻盐胁迫的不利影响。全代谢组谱分析显示，MT 处理的幼苗中类黄酮、有机酸、氨基酸及其衍生物、糖和酚酸的积累增加。有趣的是，N,N'-二邻苯甲酰基腐胺是一种已知的抗氧化化合物，在 MT 处理后大量积累。
总之，我们的研究表明 MT 是陆地棉的盐胁迫调节剂，通过调节光合作用（及其相关途径）、类黄酮、ROS 清除、激素信号、亚油酸代谢和离子稳态相关基因的表达来减轻盐胁迫的影响。
