Cloning and functional analysis of the soybean GmARA6a gene in response to salt stress

Vesicle trafficking plays a crucial role in plant responses to salt stress. <italic>ARA6 (RabF1) </italic>positively regulates salt tolerance by mediating vesicle transport between endosomes and the plasma membrane. In this study, <italic>GmARA6a</italic> 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 <italic>GmARA6a</italic> was assessed across various tissues and under salt stress conditions. To evaluate its functional role in salt tolerance, we used <italic>Arabidopsis ara6</italic> mutants, complemented lines (<italic>Com-1</italic>, <italic>Com-2</italic>), and overexpression lines (OE-1, OE-2). The <italic>GmARA6a</italic> 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 <italic>GmARA6a</italic> localizes to the plasma membrane and multivesicular bodies (MVBs). Its expression was induced by salt stress, particularly in soybean roots. Under salt stress conditions, <italic>Arabidopsis ara6</italic> mutants exhibited a salt-sensitive phenotype compared to wild-type plants, while <italic>GmARA6a</italic> 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 <italic>GmARA6a</italic> may contribute to salt tolerance by modulating the SOS signaling pathway and vesicle trafficking. These findings provide new insights into the functional role of <italic>GmARA6a</italic> in plant salt stress responses.