Genome-Wide Identification of the RALF Gene Family and Expression Pattern Analysis in Zea mays (L.) under Abiotic Stresses

Rapid Alkalization Factor (RALF) is a signaling molecule in plants that plays a crucial role in growth and development, reproductive processes, and responses to both biotic and abiotic stresses. Although RALF peptides have been characterized in and rice, a comprehensive bioinformatics analysis of the gene family in maize is still lacking. In this study, we identified 20 genes in the maize genome. Sequence alignment revealed significant structural variation among the family genes. Phylogenetic analysis indicates that RALF proteins from , rice, and maize can be classified into four distinct clades. Duplication events suggest that the expansion of the gene family in maize primarily relies on whole-genome duplication. genes are widely expressed across various tissues; are highly expressed in roots, while are predominantly expressed in anthers. RNA-seq and RT-qPCR demonstrated that the expression levels of , , and were significantly up-regulated and down-regulated in response to PEG and NaCl stresses, respectively. Overall, our study provides new insights into the role of the gene family in abiotic stress.