Uncovering the pivotal roles of two pairs of maize CLE genes in regulating leaf senescence and conferring drought tolerance through genome-wide analysis

The CLAVATA3/Embryo surrounding region-related (CLE) peptide family constitutes the most extensive group of small peptide hormones in plants, exhibiting widespread distribution across diverse plant species and playing pivotal regulatory roles in numerous fundamental physiological processes throughout various developmental stages. However, the systematic identification and functional characterization of the CLE gene family in maize, particularly with respect to its regulatory functions in leaf senescence and drought stress responses, remain unreported to date. Herein, we performed a comprehensive genome-wide systematic identification and multifaceted characterization of 35 maize CLE genes, encompassing in-depth analyses of their signal peptide sequences, physicochemical properties, chromosomal distribution patterns, phylogenetic relationships, gene structural architectures, conserved protein domain organizations, promoter cis-regulatory elements, as well as spatiotemporal expression profiles. Transcriptomic profiling demonstrated that the majority of ZmCLE genes exhibit distinct tissue-specific expression patterns in maize, implying their potential regulatory functions in growth and development as well as stress response. Further qRT-PCR analysis revealed that ZmCLE3 and ZmCLE16 likely share conserved biological functions in regulating leaf senescence, whereas ZmCLE4 and ZmCLE15 may play a potential role in enhancing plant drought tolerance by modulating stomatal aperture regulation. Subsequent experimental validation confirmed our hypothesis that ZmCLE3 and ZmCLE16 function as key regulatory genes governing leaf senescence in plants, whereas ZmCLE4 and ZmCLE15 act as pivotal regulatory genes controlling drought resistance mechanisms. Overall, this study establishes an integrated theoretical framework that systematically elucidates the molecular mechanisms underlying the regulatory roles of the maize CLE gene family in controlling leaf senescence and abiotic stress responses.