General control non-repressible 20 functions in the salt stress response of Arabidopsis seedling by modulating ABA accumulation

Abstract

Although most ABC proteins are transporters, proteins of the ABC F subfamily lack the required transmembrane domains and, consequently, their functions are poorly understood. Here, we report that the F subfamily member general control non-repressible 20 (GCN20) mediates ABA and ROS accumulation in plants during salt stress. We demonstrate that salt conditions induce the expression of GCN20. The gcn20–1 mutant with more ABA accumulation is more sensitive to high salinity than the wild type in terms of decreased seed germination and fresh weight, and decreasing ABA accumulation can rescue reduced salt tolerance of the mutant, revealing the involvement of ABA in GCN20-mediated salt stress response. Consistently, salt stress promotes a number of stress-related and ABA signal-responsive genes expression in the gcn20–1 plants. In addition, the gcn20–1 plants have less CAT and SOD activity, and thus more ROS than wild-type plants when subjected to salt stress. These findings display that GCN20 is closely involved in the stress response caused by high salinity through modulation of ABA accumulation.