Identification and Functional Characterization of the CrRLK1L Gene Family in Salt Tolerance in Rice (Oryza sativa L.)

Background: As key members of the plant receptor-like kinase family, rice CrRLK1Ls play diverse roles in plant growth, development, and stress responses. Although rice CrRLK1Ls have been initially characterized, our understanding of their functions remains limited. Methods: We identified OsCrRLK1L genes via Hidden Markov Model (HMM) searches against the rice genome. Subsequent analyses encompassed their physicochemical properties, chromosomal distribution, gene structure, phylogenetic relationships, conserved domains, and cis-acting elements.Salt-responsive candidates were screened using a GEO dataset, and their expression profiles were validated under salt stress using quantitative real-time PCR. Result: A total of 36 OsCrRLK1L genes, all containing both Malectin and tyrosine kinase domains, were identified in the rice genome and showed an uneven chromosomal distribution. Phylogenetic analysis classified them into three subclades, with Group II and Group III being specific to rice and Arabidopsis thaliana, respectively. Promoter analysis revealed that the promoter regions of these genes contained an abundance of cis-acting elements related to hormone and stress responses. RNA-Seq and enrichment analysis indicated that OsCrRLK1L genes exhibit tissue specificity and participate in salt stress responses. Furthermore, CrRLK1L2 and CrRLK1L10 showed tissue-specific differential expression under salt stress. Conclusions: In summary, our study lays the groundwork for future research into the biological roles of OsCrRLK1L genes during salt stress.