Transcriptomic analysis revealed that multiple metabolic pathways involved in the synergy response to salt stress induced by exogenous GABA at different stages in tomato plants

Abstract

Abstract Background Plant salt tolerance is controlled by complex metabolic pathways. Gamma-aminobutyric acid (GABA) can act as a signaling molecule and metabolite to enhance plant salt tolerance. However, it is not clear which metabolic pathway and gene plays a major role in the defense system under the continuous influence of salt stress. The transcriptome data and metabolite analysis of 33 samples of tomato (Solanum lycopersicum L.) seedling leaves under 175 mmol·L−1 stress for 0-96 h showed that the GABA+Na (GN) group showed strong salt tolerance. Results The time-dependent pattern of gene enrichment showed that the gene changes were mainly concentrated at 6 h, 48 h and 96 h. The amino acid synthesis, especially GABA, and some transporter-related genes play an important role in increasing the amino acid content of GN group plants. Accumulation of L-Phenylalanine induces upregulation and flavonoid accumulation of key genes in the phenylpropane and flavonoid pathways. Gene changes in the zeatin biosynthesis pathway explained the increase in zeatin. The up-regulated expression of major ion transporters and sugar transporters indicated that GABA maintained a relatively stable osmotic pressure by accelerating ion regionalization and regulating entry of small molecules into cells. AP2/ERF, bHLH and MYB transcription factors may play a regulatory role in this process. Conclusions Our study proposes a new temporal time model to elucidate various metabolic pathways, as well as amino acids, sugars, ion transporter and transcription factors how do synergize in GABA at different stages of salt stress tolerance in tomato.