Combined Proteomics and Metabolism Analysis Unravels Prominent Roles of Antioxidant System in the Prevention of Alfalfa (Medicago sativa L.) against Salt Stress

Abstract

Alfalfa is the most extensively cultivated forage legume worldwide, and salinity constitutes the main environmental scourge limiting its growth and productivity. To unravel the potential molecular mechanism involved in salt tolerance in alfalfa, we accomplished a combined analysis of parallel reaction monitoring-based proteomic technique and targeted metabolism. Based on proteomic analysis, salt stress induced 226 differentially abundant proteins (DAPs). Among them, 118 DAPs related to the antioxidant system, including glutathione metabolism and oxidation-reduction pathways, were significantly up-regulated. Data are available via ProteomeXchange with identifier PXD017166. Overall, 107 determined metabolites revealed that the tricarboxylic acid (TCA) cycle, especially the malate to oxaloacetate conversion step, was strongly stimulated by salt stress. This leads to an up-regulation by about 5 times the ratio of NADPH/NADP+, as well as about 3 to 5 times in the antioxidant enzymes activities, including those of catalase and peroxidase and proline contents. However, the expression levels of DAPs related to the Calvin–Benson–Bassham (CBB) cycle and photorespiration pathway were dramatically inhibited following salt treatment. Consistently, metabolic analysis showed that the metabolite amounts related to carbon assimilation and photorespiration decreased by about 40% after exposure to 200 mM NaCl for 14 d, leading ultimately to a reduction in net photosynthesis by around 30%. Our findings highlighted also the importance of the supplied extra reducing power, thanks to the TCA cycle, in the well-functioning of glutathione to remove and scavenge the reactive oxygen species (ROS) and mitigate subsequently the oxidative deleterious effect of salt on carbon metabolism including the CBB cycle.

Zinc and Copper Enhance Cucumber Tolerance to Fusaric Acid by Mediating Its Distribution and Toxicity and Modifying the Antioxidant System

“…Therefore, when the plant was subjected to FA stress again, the oxidative stress caused by FA would be alleviated ( Figure 5). The antioxidant defense machinery is of paramount importance in protecting plants against oxidative damages [71,72]. These different roles may contribute to the different performances of plants roots given high Zn or Cu and tolerance to FA ( Figure 5C).…”

Jasmonic Acid in Plant Abiotic Stress Tolerance and Interaction with Abscisic Acid

“…Salt stress is caused by high concentrations of salts in the soil or water supply, which restricts water uptake and disturbs the osmotic balance, leading to a variety of physiological and developmental disorders, such as ROS accumulation, photosynthetic inhibition, membrane leakage, and growth suppression [96][97][98][99][100]. In Arabidopsis, the cellular JA level increased by 2.8-fold in response to a 24 h treatment with 100 mM NaCl, and the increased JA level activated the JA response.…”

Evaluation on reprogramed biological processes in transgenic maize varieties using transcriptomics and metabolomics

“…The metabolomics profiling analysis was performed by Metabolon software (Durham, NC, USA). For two identified metabolites, i.e., galacturonic acid and l -asaparagine, the contents of two metabolites were further determined by LC–MS/MS (AB Sciex Qtrap 6,500; SCIEX) with standard curve as described previously 38 . Metabolites were identified by analyzing retention times and mass spectra with those for reference compounds as well as the entries of the mass spectra libraries NIST02 and Golm metabolome database ( http://csbdb.mpimp-golm.mpg.de/csbdb/gmd/gmd.html ).…”