High Basal Expression and Dual Stress Responsiveness of Soybean () Resistance Gene .

Genes involved in disease resistance are crucial for plant immune systems, yet their transcriptional regulatory mechanisms remain poorly understood. , a key member of the soybean mosaic virus resistance cluster (SRC), encodes a Ca-binding EF-hand domain and possesses antiviral activity, but its expression regulation is unclear. Here, we systematically analyzed 4085 soybean () transcriptome datasets and conducted SMV inoculation experiments to characterize expression patterns. -acting element analysis identified 12 regulatory elements in the promoter, including salicylic acid (SA)-responsive elements. Furthermore, a :: reporter vector was constructed and functional analysis was performed in tobacco () and transgenic . exhibited significantly higher basal expression than typical resistance genes ( genes) and was induced by SMV infection, SA treatment, and Ca supplementation, with peak expression at 2-5 h post-treatment (hpi). In transgenic tobacco overexpressing , neither SMV nor Ca could induce :: expression, demonstrating that transcriptional regulation is mediated through SA signaling pathways. showed predominant expression in roots and leaves and responded to temperature stress. Transgenic plants overexpressing exhibited enhanced tolerance to both 12 °C and 37 °C temperature stress. This study elucidates the molecular mechanisms underlying transcriptional regulation through Ca and SA signaling pathways, revealing its dual role in both biotic and abiotic stress responses, especially in temperature stress.