GmVQ32 enhances tolerance to aluminium toxicity and low-phosphorus stress in Arabidopsis

Soybean ( Glycine max ) productivity is frequently limited by aluminium (Al) toxicity and phosphorus (P) deficiency in acidic soils. GmVQ32, a VQ motif-containing gene, was previously identified as an Al-inducible gene through transcriptomic analysis, but its role in soybean responses to Al 3+ toxicity and phosphate deficiency remains uncharacterized. In this study, GmVQ32 was identified and cloned from soybean. Bioinformatic analysis revealed that GmVQ32 belongs to subgroup V of the VQ family, and that its promoter contains predicted cis -acting elements associated with ABA, SA, and various stress responses. Tissue-specific expression analysis revealed that GmVQ32 is constitutively expressed in various soybean organs, with the highest transcript abundance in flowers. qRT‒PCR analysis demonstrated that GmVQ32 expression significantly increased under both AlCl₃ and low-phosphorus (-P) treatments. Subcellular localization assays confirmed that the GmVQ32 protein is localized in the nucleus. Yeast two-hybrid assays demonstrated that GmVQ32 has transcriptional activation activity in the yeast reporter system and that it physically interacts with GmWRKY21 in yeast. Compared with wild-type plants, transgenic Arabidopsis plants overexpressing GmVQ32 presented increased relative root elongation, reduced Al accumulation, increased proline content, and decreased malondialdehyde levels under Al stress. In addition, the GmVQ32 transgenic lines under the -P treatments presented greater biomass, more developed root systems, and higher P content. Furthermore, the expression levels of several Al stress-responsive marker genes, including AtALS3 , AtALMT1 , AtMATE and AtSTOP1 , were significantly upregulated in transgenic Arabidopsis under Al 3+ toxicity treatment. The expression of several P-responsive marker genes, such as AtMGD2 , AtPAP10 , AtPHO1 and AtPHR1 , significantly increased in the -P-treated transgenic Arabidopsis plants. Functional analyses revealed that overexpression of GmVQ32 in soybean hairy roots and Arabidopsis significantly reduced Al³⁺ accumulation in plant roots. Collectively, these findings demonstrate that GmVQ32 enhances plant tolerance to Al 3+ toxicity and phosphorus deficiency, likely through the modulation of stress-responsive transcriptional networks. This study highlights that GmVQ32 is a promising candidate gene for improving soybean adaptation to suboptimal soil conditions.