Cross-Species Analysis of ABA-Induced Phosphosignaling Landscapes in Rice, Soybean, and Arabidopsis

Background: Abscisic acid (ABA) is a key phytohormone that regulates plant growth and stress responses through protein phosphorylation. While ABA-induced phosphosignaling has been extensively studied in Arabidopsis thaliana, its conservation and divergence across plant species remain unclear. Methods: Here, we performed phosphoproteomic analysis using LC-MS/MS in Arabidopsis, rice (Oryza sativa), and soybean (Glycine max) to compare ABA-responsive phosphorylation profiles among monocots, dicots, and legumes. Results: ABA treatments on Arabidopsis, rice, and soybean seedlings yielded approximately 24,604, 18,865, and 24,930 phosphopeptides, respectively. Comparative analyses revealed both conserved and species-specific ABA-responsive phosphoproteins. Conclusions: This work provides insights into the evolutionary diversification of ABA signaling and its potential applications in improving crop stress tolerance.