Integrated metabolomic and transcriptomic analyses reveal the roles of alanine, aspartate and glutamate metabolism and glutathione metabolism in response to salt stress in tomato

Salt stress affects different phases of the life cycle of tomato (Solanum lycopersicum) plants, including germination, growth, and development, resulting in significant yield losses. However, global metabolites and genes that respond to salt stress in tomato remain unclear. In this study, we treated tomato inbred line '895′ with or without 150 mM NaCl to clarify adaptive responses to salt stress by metabolomic and transcriptomic characterization. A total of 428 differentially accumulated metabolites (DAMs) and 1867 differentially expressed genes (DEGs) were obtained under salt stress. KEGG analysis indicated that these DAMs and DEGs were mainly enriched in carbon and nitrogen metabolism-related pathways. Based on integrated analysis, we found that alanine, aspartate and glutamate metabolism might negatively respond to salt stress. Moreover, the changes in metabolite levels, gene expressions, and antioxidant enzyme activities involved in glutathione-glutathione disulfide (GSH-GSSG) and glutathione-ascorbate (GSH-AsA) cycles revealed a crucial role of glutathione metabolism in response to salt stress in tomato. Thus, our study provides a theoretical basis for further exploring the mechanism of tomato plants in response to salt stress.