Institute of Ecological and Environment Restoration in Mine Areas of West China, Xi'an University of Science and Technology, Xi'an 710054, China.
College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China.
J Agric Food Chem. 2024 Jul 31;72(30):16812-16824. doi: 10.1021/acs.jafc.4c04009. Epub 2024 Jul 17.
This study investigates how extracellular polymeric substances (EPS) synthesized by dark septate endophytic (DSE) improve alfalfa's drought resistance. Drought stress was simulated in hydroponic culture, and roots were treated with different EPS concentrations to determine their effects on drought tolerance and applicable concentrations. Hydroponic solutions with 0.25 and 0.50% EPS concentrations alleviated leaf wilting and increased total plant fresh weight by 35.8 and 57.7%, respectively. SEM shows that EPS attached to the roots and may have served to protect the root system. EPS treatment significantly depressed the MDA contents of the roots, stems, and leaves. Roots responded to drought stress by increasing soluble sugar contents and antioxidant enzyme activities, while mitigating stem and leaf stress by synthesizing lipid compounds, amino acids, and organic acid metabolites. Five metabolites in the stem have been reported to be associated with plant stress tolerance and growth, namely 3--methyl 5--(2-methyl propyl) (4S)-2,6-dimethyl-4-(2-nitrophenyl)-3,4-dihydropyridine-3,5-dicarboxylate, malic acid, PA (20:1(11Z)/15:0), -methyl-4,6,7-trihydroxy-1,2,3,4-tetrahydroisoquinoline, and 2-(-glutathionyl) acetyl glutathione. In summary, EPS treatment induced oxidative stress and altered plant metabolism, and this in turn increased plant antioxidant capacity. The results provide a theoretical basis for the application of EPS in commercial products that increase plant resistance and ecological restoration.
本研究探讨了深色有隔内生真菌（DSE）合成的胞外聚合物（EPS）如何提高紫花苜蓿的抗旱性。在水培培养中模拟干旱胁迫，并用不同浓度的 EPS 处理根系，以确定其对耐旱性的影响和适用浓度。浓度为 0.25%和 0.50%的 EPS 水培溶液缓解了叶片萎蔫，并分别使整株植物鲜重增加了 35.8%和 57.7%。SEM 显示，EPS 附着在根上，可能起到了保护根系的作用。EPS 处理显著降低了根、茎和叶的 MDA 含量。根系通过增加可溶性糖含量和抗氧化酶活性来应对干旱胁迫，同时通过合成脂类化合物、氨基酸和有机酸代谢物来减轻茎和叶的胁迫。茎中报道的五种代谢物与植物的应激耐受和生长有关，即 3--甲基 5--(2-甲基丙基)-(4S)-2,6-二甲基-4-(2-硝基苯基)-3,4-二氢吡啶-3,5-二羧酸酯、苹果酸、PA(20:1(11Z)/15:0)、-甲基-4,6,7-三羟基-1,2,3,4-四氢异喹啉和 2-(-谷胱甘肽基)乙酰谷胱甘肽。总之，EPS 处理诱导了氧化应激和改变了植物代谢，这反过来又增加了植物的抗氧化能力。研究结果为 EPS 在增加植物抗性和生态恢复的商业产品中的应用提供了理论依据。
