Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) plays pivotal roles in regulating plant growth and development, mediating intercellular signal transduction, and modulating responses to environmental stresses. However, a comprehensive genome-wide identification and analysis of the CrRLK1L gene family in maize remains elusive. In this study, a total of 24 CrRLK1L genes were identified in the maize whole genome. A phylogenetic analysis further revealed that CrRLK1L proteins from Arabidopsis, rice, and maize were grouped into nine distinct subgroups, with subgroup IV being unique to maize. Gene structure analysis demonstrated that the number of introns varied greatly among ZmCrRLK1L genes. Notably, the genome-wide duplication (WGD) events promoted the expansion of the ZmCrRLK1L gene family. Compared with Arabidopsis, there were more collinear gene pairs between maize and rice. Tissue expression patterns indicated that ZmCrRLK1L genes are widely expressed in various tissues, with ZmCrRLK1L5/9 specifically highly expressed in roots, and ZmCrRLK1L8/14/16/21/22 expressed in anthers. Additionally, RNA-seq and RT-qPCR analyses revealed that the expression of ZmCrRLK1L1/2/20/22 genes exhibited different expression patterns under drought and salt stresses. In summary, our study lays a foundation for elucidating the biological roles of ZmCrRLK1L genes in maize growth and development, reproductive development, and stress responses.

Background: The Dirigent (DIR) gene family is pivotal for lignin polymerization and stress adaptation in plants, yet its systematic characterization in Sorghum bicolor (S. bicolor), a critical bioenergy crop, remains underexplored. Methods: Leveraging the S. bicolor genome database, we conducted a genome-wide identification, phylogenetic classification, and expression profiling of the DIR gene family. Evolutionary dynamics, gene structure variations, promoter cis-regulatory elements, and spatiotemporal transcriptome patterns were analyzed using bioinformatics and experimental validation (RT-qPCR). Results: A total of 53 SbDIR genes were systematically identified, exhibiting uneven chromosomal distribution. Phylogenetic analysis clustered them into five clades (DIR-a, DIR-b/d, DIR-c, DIR-e, DIR-f), with subfamily-specific exon number variations suggesting functional divergence. Evolutionary studies revealed tandem duplication (TD) as the primary driver of family expansion, accompanied by strong purifying selection. Promoter analysis highlighted abundant hormone- and stress-responsive cis-elements. Tissue-specific RNA-seq data revealed root-enriched expression of SbDIR2/4/18/39/44/53, implicating their roles in root development. Notably, SbDIR39 and SbDIR53 were significantly upregulated (2.8- and 5-fold, respectively) under 150 mM NaCl stress, underscoring their stress-responsive functions. Conclusions: This study provides the first comprehensive atlas of the DIR gene family in S. bicolor, elucidating its evolutionary mechanisms and tissue-specific/stress-induced expression profiles. Key candidates (SbDIR39/53) were identified as promising targets for molecular breeding or CRISPR-based editing to enhance stress resilience in S. bicolor. These findings lay a foundation for translating genomic insights into agronomic improvements.