Proteome Analysis of the Leaves of Two Inbred Maize Lines (MSO2 and TSO1) and Their Hybrid (SCO1) Using Two-Dimensional Electrophoresis

Maize (Zea mays L.) is one of the most important cereal crops globally. Proteomics, the comprehensive study of the entire set of polypeptides expressed by the genes of a cell within a specific organ or tissue at a given developmental stage and under defined growth conditions, was employed in this study to analyze protein expression changes in the leaves of two maize inbred lines (MS02 and TS01) and their hybrid progeny, SC01. Protein samples were collected at the full-plant growth stage and post-pollination to investigate these changes. Total protein was extracted from maize leaves using the TCA-acetone method and separated via two-dimensional electrophoresis. Protein molecular weights and isoelectric points were determined using ImageMaster 2D Platinum 6.0 software, and mass spectrometry was used for precise protein identification. The analysis identified 539 proteins in SC01, 258 in TS01, and 157 in MS02, with 33 proteins exhibiting significant expression changes. Among these, 11 spots in SC01 showed reduced expression, while 22 spots exhibited increased expression. Functional categorization revealed that the majority of these proteins were involved in defense responses (33%), photosynthesis (21%), and signaling and channel functions (21%). Fewer changes were observed in heterosis-related proteins (12%), proteins associated with metabolism and energy production (9%), and structural and replacement proteins (3%). This study identified key proteins involved in defense mechanisms, photosynthesis, and signal transduction through the application of proteomics and the analysis of protein expression patterns in the leaves of two maize inbred lines and their hybrid. The differential expression of these proteins in the SC01 hybrid contributed to its enhanced performance and stability compared to the parent lines. These findings provide a scientific foundation for improving genetic traits and developing hybrid maize varieties with increased resistance to environmental stresses and pathogens.