Vesicle trafficking plays a crucial role in plant responses to salt stress. ARA6 (RabF1) positively regulates salt tolerance by mediating vesicle transport between endosomes and the plasma membrane. In this study, GmARA6a was cloned from soybean and analyzed using bioinformatics approaches. Subcellular localization was examined through BFA and WM treatments, as well as colocalization with AtARA6. The expression pattern of GmARA6a was assessed across various tissues and under salt stress conditions. To evaluate its functional role in salt tolerance, we used Arabidopsis ara6 mutants, complemented lines (Com-1, Com-2), and overexpression lines (OE-1, OE-2). The GmARA6a gene, with a full-length coding sequence of 603 bp encoding a 200-amino-acid protein, was successfully cloned. The protein contains four conserved ARA6-family domains, an effector-binding region, and a unique N-terminal “MGCXSS” motif. Subcellular localization analysis revealed that GmARA6a localizes to the plasma membrane and multivesicular bodies (MVBs). Its expression was induced by salt stress, particularly in soybean roots. Under salt stress conditions, Arabidopsis ara6 mutants exhibited a salt-sensitive phenotype compared to wild-type plants, while GmARA6a overexpression lines showed improved growth, enhanced antioxidant enzyme activity, reduced membrane damage and lipid peroxidation, and lower levels of H2O2 and O2܋accumulation. Expression analysis of related genes suggested that GmARA6a may contribute to salt tolerance by modulating the SOS signaling pathway and vesicle trafficking. These findings provide new insights into the functional role of GmARA6a in plant salt stress responses.
Zhang et al. (Mon,) studied this question.