Molecular Mechanisms and Crosstalk Signaling in Soybean’s Response to Water Deficit and Excess: Implications for Stress Resilience and Productivity

Soybean plays a crucial role in global food security and the economy, but its yield is often limited by water deficit (WD) and water excess (WE). Understanding the molecular mechanisms that regulate responses to these stresses is essential to improve crop resilience. In this study, we analyzed nine ABA-induced genes involved in WD and WE signaling using transcriptome libraries, RT-qPCR, gas exchange analysis, and root morphology. A total of 4412 and 2597 genes were differentially expressed under WE and WD, respectively. The response to exogenous ABA varied between conditions, reflecting stress-specific adaptations. Among 10 genes exclusively expressed under WE, only ERF1 and Peroxydase showed increased transcript levels after ABA treatment, being similarly regulated under both WD and WE. These results reveal distinct molecular and physiological responses to ABA depending on water status, highlighting potential targets for genetic improvement. The identified genes provide insights into ABA-mediated regulation of soybean stress tolerance and represent promising candidates for breeding strategies aimed at enhancing resilience to water-related stresses. Ultimately, this study contributes to a deeper understanding of soybean adaptation mechanisms, supporting sustainable crop management and productivity under challenging environmental conditions.