Importin α (IMPα) proteins are key mediators of nucleocytoplasmic transport and play crucial roles in plant development and stress adaptation. Here, we performed a genome-wide identification of the IMPα gene family in Glycine max, followed by gene structure and conserved motif analyses, chromosomal distribution and duplication inference, synteny and selection (Ka/Ks) analyses, and expression profiling across tissues and stress conditions using public RNA-seq datasets and expression browsers. The GmIMPα genes exhibited diverse gene structures and conserved motifs, suggesting functional diversification within the family. Segmental duplication was identified as the main contributor to family expansion, and most duplicated gene pairs underwent purifying selection. Promoter analysis revealed numerous stress- and hormone-responsive cis-elements, implying complex transcriptional regulation. Expression profiling demonstrated that GmIMPα5 and GmIMPα7 were strongly induced under drought, heat, and salt stresses, indicating potential roles in abiotic stress tolerance. Collectively, our results provide a comprehensive framework for the evolution and functional divergence of the GmIMPα family in soybean and offer candidates for improving stress resilience.

Introduction: Soil salinity severely compromises rice ( Oryza sativa L.) growth and grain yield by disrupting ionic and osmotic homeostasis. Although transcriptome profiling has advanced understanding of salt-stress responses in rice, the conservation of co-expression networks across genetic backgrounds and the relationship between network connectivity and transcriptional induction remain poorly characterized. Methods: We performed integrated RNA sequencing and weighted gene co-expression network analysis (WGCNA) on three japonica rice varieties under control (0 mM), moderate (85.6 mM), and severe (136.9 mM) NaCl stress. Results: All three varieties exhibited basal salt tolerance. Differential expression analysis identified 2,067 and 4,900 non-redundant differentially expressed genes (DEGs) under moderate and severe stress, with 205 and 1,093 DEGs shared across the three varieties, respectively. WGCNA identified 32 co-expression modules. The brown module showed the strongest dose-dependent response to salt stress and was enriched in phenylpropanoid biosynthesis, plant hormone signal transduction, and MAPK signaling; its eigengene was highly concordant across varieties (mean r = 0.987), consistent with a shared leaf-level transcriptional program. Across brown-module genes, intramodular connectivity and salt-induced fold change were positively but only moderately correlated (Pearson r = 0.377): OsDREB1A was the most connected gene but not the most strongly induced, whereas LOC_Os10g35080 was the most strongly induced yet ranked 14th in connectivity. In the 15-node hyperosmotic salinity response subnetwork, no single hub dominated, and OsDREB1A occupied a peripheral position. Discussion: Connectivity and induction thus reflect complementary aspects of the salt-stress response, and candidate hub genes for molecular breeding should be prioritized by both criteria jointly, followed by validation across diverse genetic backgrounds.