Integrated genomic and transcriptomic analysis of maize SRC2-like genes highlights divergent roles in abiotic stress...

SRC2 (soybean genes regulated by cold 2) is a protein that contains a C2 domain and plays a vital role in plant stress responses. In this study, we identified a total of 15 SRC2-like genes (ZmSRC2L1-ZmSRC2L15) in maize and systematically characterized their molecular properties, genomic distribution, promoter features, subcellular localization, and expression under abiotic stress conditions. We confirmed that the ZmSRC2L genes are unevenly distributed across chromosomes 1-8, encoding proteins of 212-402 amino acids, with molecular weights (MWs) ranging from 21.93 to 42.52 kDa. These proteins retain a conserved C2_SRC2_like domain while exhibiting subfamily-specific variations. Promoter analysis revealed the presence of cis-elements enriched in light, hormones, and stress responses, and predicted regulation by multiple transcription factor families, particularly ERF and MYB. Subcellular localization analysis revealed that the ZmSRC2L proteins are distributed across multiple cellular compartments. Transcriptome and RT-qPCR analyses demonstrate that gene expression is tissue-specific under stresses such as drought, heat, and cold. Functional validation using Ds insertion mutants indicated that the loss of ZmSRC2L2 specifically impaired drought tolerance without affecting responses to heat or cold. Overall, these results provide a comprehensive framework for understanding the role of the ZmSRC2L family in abiotic stress responses and highlight ZmSRC2L2 and other members as promising targets for enhancing maize stress resistance.