Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu 611130, China.
Department of Plant Soil and Microbial Sciences, Michigan State University , East Lansing, Michigan 48824, United States.
J Proteome Res. 2017 Aug 4;16(8):3039-3052. doi: 10.1021/acs.jproteome.7b00334. Epub 2017 Jul 25.
Increased endogenous chitosan (CTS) could be associated with improved drought resistance in white clover (Trifolium repens). Plants were pretreated with or without 1 mg/mL CTS and then were subjected to optimal or water-limited condition in controlled growth chambers for 6 days. Phenotypic and physiological results indicated that exogenous CTS significantly improved drought resistance of white clover. Metabolome results showed that exogenous CTS induced a significant increase in endogenous CTS content during dehydration accompanied by the maintenance of greater accumulation of sugars, sugar alcohols, amino acids, organic acids, and other metabolites (ascorbate, glutathione, flavonoids, putrescine, and spermidine). These compounds are associated with osmotic adjustment, antioxidant defense, stress signaling, and energy metabolism under stress condition. Similarly, transcriptome revealed that many genes in relation to amino acid and carbohydrate metabolism, energy production and conversion, and ascorbate-glutathione and flavonoid metabolism were significantly up-regulated by CTS in response to dehydration stress. CTS-induced drought resistance was associated with the accumulation of stress protective metabolites, the enhancement of ascorbate-glutathione and tricarboxylic acid cycle, and increases in the γ-aminobutyric acid shunt, polyamine synthesis, and flavonoids metabolism contributing to improved osmotic adjustment, antioxidant capacity, stress signaling, and energy production for stress defense, thereby maintaining metabolic homeostasis under dehydration stress.
内源性壳聚糖 (CTS) 的增加可能与白三叶草（Trifolium repens）抗旱性的提高有关。将植物用或不用 1mg/mL CTS 预处理，然后在控制生长室中置于最佳或水分限制条件下 6 天。表型和生理结果表明，外源性 CTS 显著提高了白三叶草的抗旱性。代谢组学结果表明，外源性 CTS 在脱水过程中诱导内源性 CTS 含量显著增加，同时保持更多的糖、糖醇、氨基酸、有机酸和其他代谢物（抗坏血酸、谷胱甘肽、类黄酮、腐胺和亚精胺）的积累。这些化合物与胁迫条件下的渗透调节、抗氧化防御、应激信号和能量代谢有关。同样，转录组学表明，许多与氨基酸和碳水化合物代谢、能量产生和转化以及抗坏血酸-谷胱甘肽和类黄酮代谢有关的基因在 CTS 响应脱水胁迫时被显著上调。CTS 诱导的抗旱性与应激保护代谢物的积累、抗坏血酸-谷胱甘肽和三羧酸循环的增强以及γ-氨基丁酸支路、多胺合成和类黄酮代谢的增加有关，这些有助于提高渗透调节、抗氧化能力、应激信号和能量产生以进行应激防御，从而在脱水胁迫下维持代谢平衡。
