Zhang Xiaoxia, Zhu Wenxuan, Liu Zirui, Ren Xiangling, Li Yingao, Li Guomin, Wang Jingzhuo, Zhu Xiaoyan, Shi Yinghua, Wang Chengzhang, Li Defeng, Sun Hao
Key Laboratory of Forage Processing, College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, 450046, China.
Henan Animal Husbandry Technology Extension Station, Zhengzhou, 450046, China.
BMC Plant Biol. 2025 May 14;25(1):637. doi: 10.1186/s12870-025-06665-w.
Drought stress is a predominant abiotic factor contributing to reduced crop yields globally. Therefore, exploring the molecular mechanism of drought control is of great significance to improve drought resistance and ultimately achieve crop yield increase. As a plant endogenous hormone, melatonin plays a key role in the regulation of abiotic stress, but the key genes and metabolic pathways of melatonin mediated drought resistance regulation in alfalfa have not been fully revealed. Based on transcriptomics and physiological index detection, this study aimed to explore the regulatory mechanism of melatonin in alleviating drought stress during alfalfa germination.
The findings revealed that alfalfa seedlings treated with melatonin exhibited higher germination rates, increased shoot length, and greater fresh weight compared to those exposed solely to drought stress. Additionally, there was a reduction in the levels of malondialdehyde (MDA) and superoxide anion (O), while the activity and concentration of superoxide dismutase (SOD), peroxidase (POD), and glutathione (GSH) were enhanced to varying extents. To investigate the molecular mechanism underlying melatonin-mediated drought resistance in alfalfa, we performed a transcriptomic analysis on the seedlings. In the drought treatment group, we identified a total of 1,991 differentially expressed genes (DEGs), comprising 778 up-regulated and 1,213 down-regulated genes. Conversely, in the melatonin-treated group, we discovered 2,336 DEGs, including 882 up-regulated and 1,454 down-regulated genes.
Through the application of GO functional annotation and KEGG pathway enrichment analysis, we discovered that DEGs were predominantly enriched in pathways related to flavonoid and isoflavone biosynthesis, plant hormone biosynthesis and signal transduction, glutathione metabolism, and MAPK signaling, and the ABC transporter signaling. Notably, the DEGs added to the MT group showed greater enrichment in these pathways. This suggests that MT mitigates drought stress by modulating the expression of genes associated with energy supply and antioxidant capacity. These findings hold significant reference value for breeding drought-tolerant alfalfa and other crops.
干旱胁迫是导致全球作物减产的主要非生物因素。因此，探索干旱调控的分子机制对于提高抗旱性并最终实现作物增产具有重要意义。褪黑素作为一种植物内源激素，在非生物胁迫调控中发挥关键作用，但苜蓿中褪黑素介导的抗旱调控关键基因和代谢途径尚未完全揭示。基于转录组学和生理指标检测，本研究旨在探讨褪黑素在缓解苜蓿萌发期干旱胁迫中的调控机制。
研究结果表明，与仅遭受干旱胁迫的苜蓿幼苗相比，用褪黑素处理的苜蓿幼苗发芽率更高、茎长增加且鲜重更大。此外，丙二醛（MDA）和超氧阴离子（O）水平降低，而超氧化物歧化酶（SOD）、过氧化物酶（POD）和谷胱甘肽（GSH）的活性和浓度在不同程度上得到增强。为了研究褪黑素介导苜蓿抗旱的分子机制，我们对幼苗进行了转录组分析。在干旱处理组中，共鉴定出1991个差异表达基因（DEG），包括778个上调基因和1213个下调基因。相反，在褪黑素处理组中，我们发现了2336个DEG，包括882个上调基因和1454个下调基因。
通过GO功能注释和KEGG通路富集分析，我们发现DEG主要富集在与类黄酮和异黄酮生物合成、植物激素生物合成和信号转导、谷胱甘肽代谢以及MAPK信号传导和ABC转运蛋白信号传导相关的途径中。值得注意的是，添加到MT组的DEG在这些途径中表现出更大的富集。这表明MT通过调节与能量供应和抗氧化能力相关的基因表达来减轻干旱胁迫。这些发现对培育耐旱苜蓿和其他作物具有重要参考价值。
