Comparative Proteomic Analysis of the Effects of Salicylic Acid and Abscisic Acid on Maize (Zea mays L.) Leaves

The phytohormones salicylic acid (SA) and abscisic acid (ABA) play essential roles in regulating plant growth, development, and stress responses. Using a proteomics-based approach, we compared the roles of SA and ABA in the modulation of the proteome of maize leaves. Fifty-six protein spots that showed significant expression changes on 2-DE were identified by MALDI-TOF-MS/MS. Of these, three different proteins were regulated by both SA and ABA, with consistent or inconsistent expression patterns, suggesting the synergistic and antagonistic effects of SA and ABA. The classification of differentially expressed proteins showed that both SA and ABA responsive proteins were mainly involved in photosynthesis, stress and defense response, energy and metabolism, and protein turnover. Quantitative real-time PCR analysis for selected SA and ABA responsive proteins showed that individual protein change was not predictable based on transcriptome level. This study represents the first attempt at global proteome profiling in response to SA and ABA, and it provides a better understanding of the molecular mechanisms regulated by SA and ABA.