biologia plantarum

Biologia plantarum 64: 744-752, 2020 | DOI: 10.32615/bp.2020.117

γ-Aminobutyric acid induces transcriptional changes contributing to salt tolerance in creeping bentgrass

Z. LI^*, B.Z. CHENG, Y. PENG, Y. ZHANG

Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu 611130, P.R. China

γ-Aminobutyric acid (GABA) regulates plant tolerance to abiotic stresses; however, a transcriptomic change and key stress-related genes induced by GABA have not been investigated in plants during a prolonged period of salt stress. Roots of creeping bentgrass (Agrostis stolonifera) cv. Penncross were pretreated with or without 0.5 mM GABA solution for 2 days and then subjected to salt stress for 20 days (150 mM NaCl solution for 3 d, 200 mM NaCl for another 3 d, and 250 mM NaCl for 14 d) in controlled growth chambers. The application of GABA significantly increased GABA content in roots and alleviated a salt-stress induced decrease in GABA content in leaves. This was associated with a significant increase in salt tolerance as demonstrated by a significantly higher leaf relative water content, photochemical efficiency, performance index on absorption basis, and lower electrolyte leakage in GABA-pretreated plants as compared to untreated plants under salt stress. Transcriptomic analysis found that GABA-induced salt tolerance was closely associated with saccharide, amino acid, and lipid metabolism. The GABA upregulated key differentially expressed genes including cytochrome P450 (CYP450), zinc transporter 29 (ZTP29), alpha-amylase 3 (AMY3), 3-ketoacyl-CoA synthase 6 (KCS6), aldehyde oxidase (AO), acetyl-CoA carboxylase 1 (ACC1), and magnesium-chelatase (Mg-CHT) involved in zinc homeostasis, starch degradation, and the biosynthesis of wax, fatty acid, chlorophyll, and abscisic acid, which could contribute to GABA-regulated salt tolerance. Current findings prove that GABA application is an efficient approach to enhance salt tolerance of creeping bentgrass during a prolonged period of salt stress and also provide valuable information to better understand key candidate genes and regulatory pathways of GABA-induced salt tolerance in plants.

Keywords: abscisic acid, amino acid, fatty acid, lipid metabolism, starch degradation, wax, zinc homeostasis.

Received: July 17, 2020; Revised: August 5, 2020; Accepted: August 10, 2020; Published online: October 29, 2020Show citation