Metabolomic Profiling in Selaginella lepidophylla at Various Hydration States Provides New Insights into the Mechanistic Basis of Desiccation Tolerance

• Published in: Molecular plant 2013-03, Vol.6 (2), p.369-385
• Main Authors: Yobi, Abou, Wone, Bernard W.M., Xu, Wenxin, Alexander, Danny C., Guo, Lining, Ryals, John A., Oliver, Melvin J., Cushman, John C.
• Format: Article
• Language: English
• Subjects: abiotic/environmental stress; absorption; Amino Acids - metabolism; antioxidants; apigenin; Biomarkers - metabolism; choline; citrulline; desiccation (plant physiology); desiccation tolerance; Droughts; drying; Energy Metabolism; gluconeogenesis; glucose; Glutathione - metabolism; glycolysis; mass spectrometry; membrane fluidity; metabolites; metabolome; Metabolomics; mosses and liverworts; naringenin; nitrogen; Nucleotides - metabolism; oxidative/photooxidative stress; phosphates; plant-water relations; polyunsaturated fatty acids; propionates; propionic acid; proteins; reactive oxygen species; rehydration; Selaginella; Selaginellaceae - metabolism; Selaginellaceae - physiology; stress tolerance; sucrose; sugar acids; sugar alcohols; Sugar Alcohols - metabolism; trehalose; tricarboxylic acid cycle; tricarboxylic acids; vanillic acid; Water - metabolism; water content; 代谢组学; 卷柏科; 基础代谢; 多不饱和脂肪酸; 水合状态; 空气干燥状态; 耐性机理; 脱水周期
• ISSN: 1674-2052; 1752-9867; 1752-9867
• DOI: 10.1093/mp/sss155

Selaginella lepidophylla is one of only a few species of spike mosses （Selaginellaceae） that have evolved des-iccation tolerance （DT） or the ability to ＇resurrect＇ from an air-dried state. In order to understand the metabolic basis of DT, S, lepidophylla was subjected to a five-stage, rehydration/dehydration cycle, then analyzed using non-biased, global metabolomics profiling technology based on GC/MS and UHLC/MS/MS2 platforms. A total of 251 metabolites including 167 named （66.5%） and 84 （33.4%） unnamed compounds were characterized. Only 42 （16.7%） and 74 （29.5%） of compounds showed significantly increased or decreased abundance, respectively, indicating that most compounds were produced con-stitutively, including highly abundant trehalose, sucrose, and glucose. Several glycolysis/gluconeogenesis and tricarboxylic acid （TCA） cycle intermediates showed increased abundance at 100% relative water content （RWC） and 50% RWC. Vanillate, a potent antioxidant, was also more abundant in the hydrated state. Many different sugar alcohols and sugar acids were more abundant in the hydrated state. These polyols likely decelerate the rate of water loss during the drying process as well as slow water absorption during rehydration, stabilize proteins, and scavenge reactive oxygen species （ROS）. In contrast, nitrogen-rich and y-glutamyl amino acids, citrulline, and nucleotide catabolism products （e.g. allantoin） were more abundant in the dry states, suggesting that these compounds might play important roles in nitrogen remobilization during rehydration or in ROS scavenging. UV-protective compounds such as 3-（3-hydroxyphenyl）propionate, apigenin, and naringenin, were more abundant in the dry states. Most lipids were produced constitutively, with the exception of choline phosphate, which was more abundant in dry states and likely plays a role in membrane hydration and stabilization. In contrast, several poly- unsaturated fatty acids were more abundant in the hydrated states, suggesting that these compounds likely help maintain membrane fluidity during dehydration. Lastly, S, lepidophylla contained seven unnamed compounds that displayed twofold or greater abundance in dry or rehydrating states, suggesting that these compounds might play adaptive roles in DT.