Genomic Identification and Comprehensive Characterization of the CAMTA Transcription Factor Family in Brassica rapa L

Calmodulin-binding transcription activators (CAMTAs) are a key family of transcription factors that regulate gene expression involved in plant development and mediate plant responses to a wide range of biotic and abiotic stresses. Although CAMTA genes have been surveyed in several crop species, their comprehensive characterization in Brassica rapa remains limited. In this study, we performed a genome-wide analysis and identified 12 BrCAMTA genes, dispersed across 10 chromosomes of the B. rapa genome. Phylogenetic analysis of 84 CAMTA proteins from seven plant species grouped them into four major clades, with BrCAMTAs exhibiting conserved exon-intron structures and motif compositions within their respective phylogenetic groups. Domain analysis revealed that the major CG-1 domain is conserved across all the genes. Protein-protein interaction analysis indicated that the predicted interacting proteins contain diverse domains and exhibit a variety of functions. Promoter analysis revealed a wide array of cis-regulatory elements linked to hormone signaling, stress responses, and developmental regulation. RNA-seq-based expression profiling revealed tissue-specific expression patterns, with BrCAMTA genes showing high expression in roots, stems, and callus tissues. Notably, BrCAMTA6, BrCAMTA8, and BrCAMTA11 exhibited significantly higher expression across all examined tissues. Collectively, these findings highlight the structural conservation and functional diversity of CAMTA genes in B. rapa and provide a valuable framework for future validation studies that are aimed at understanding their roles in growth, development, and environmental adaptation.