Plant Growth-Promoting Bacillus Strains Modulate Soybean Development via Proteome Remodelling

we investigated three Bacillus strains (HT1, HT2, and HT3) isolated from the soybean root microbiome for their potential plant growth-promoting and biocontrol activities. Bacillus-HT1 and HT2 significantly enhanced soybean seed germination, while Bacillus-HT3 promoted leaf area expansion, indicating strain-specific developmental effects. To elucidate the molecular basis of these effects, we conducted shotgun proteomic profiling of soybean leaves. The analysis revealed significant modulation of proteins involved in key biological processes, including amino acid metabolism, biosynthesis of cellular nitrogen and aromatic compounds, and cellular component organization and biogenesis. Notably, proteins such as anthranilate synthase and proteasome subunit alpha type were differentially expressed, suggesting the activation of growth- and defense-related pathways. These findings provide mechanistic insights into how specific Bacillus strains modulate soybean development at the molecular level and highlight their potential for use as bio-inoculants to enhance crop productivity and resilience under stress conditions.