College of Horticulture, Hebei Agricultural University, Baoding 071001, China.
Int J Mol Sci. 2022 Aug 30;23(17):9855. doi: 10.3390/ijms23179855.
Nutrient stress harms plant growth and yield. Melatonin is a biologically active, multifunctional hormone that relieves abiotic stress in plants. Although previous studies have shown that melatonin plays an important role in improving nutrient-use efficiency, the mechanism of its regulation of nutrient stress remains unclear. In this study, melatonin was applied to apple plants under nutrient stress, and morphological indices, physiological and biochemical indices, and stomatal morphology were evaluated. The response of apple plants to nutrient deficiency and the melatonin mechanism to alleviate nutrient stress were analyzed by combining ionome, transcriptome, and metabolome. The results showed that exogenous melatonin significantly alleviated the inhibitory effect of nutritional stress on the growth of apple plants by regulating stomatal morphology, improving antioxidant enzyme activity, promoting ion absorption, and utilizing and changing the absorption and distribution of minerals throughout the plant. The transcriptome results showed that melatonin alleviated nutrient stress and promoted nutrient absorption and utilization by regulating glutathione metabolism and upregulating some metal ion transport genes. The metabolome results indicated that levels of oxalic acid, L-ascorbic acid, anthocyanins (cyanidin-3-O-galactoside), lignans (lirioresinol A and syringaresinol), and melatonin significantly increased after exogenous melatonin was applied to plants under nutrient stress. These differentially expressed genes and the increase in beneficial metabolites may explain how melatonin alleviates nutrient stress in plants.
营养胁迫会损害植物的生长和产量。褪黑素是一种具有生物活性的多功能激素，它可以缓解植物的非生物胁迫。尽管先前的研究表明褪黑素在提高养分利用效率方面发挥着重要作用，但它调节养分胁迫的机制尚不清楚。在这项研究中，在养分胁迫下向苹果植株施用褪黑素，并评估其形态指标、生理生化指标和气孔形态。通过结合离子组学、转录组学和代谢组学，分析了苹果植株对养分缺乏的反应以及褪黑素缓解养分胁迫的机制。结果表明，外源褪黑素通过调节气孔形态、提高抗氧化酶活性、促进离子吸收以及利用和改变植物体内矿物质的吸收和分布，显著减轻了营养胁迫对苹果植株生长的抑制作用。转录组结果表明，褪黑素通过调节谷胱甘肽代谢和上调一些金属离子转运基因来缓解养分胁迫并促进养分吸收和利用。代谢组结果表明，在养分胁迫下向植物施加外源褪黑素后，草酸、L-抗坏血酸、花青素（矢车菊素-3-O-半乳糖苷）、木质素（丁香脂素 A 和丁香树脂醇）和褪黑素的水平显著增加。这些差异表达的基因和有益代谢物的增加可能解释了褪黑素如何缓解植物的养分胁迫。
