Comprehensive in-silico characterization and expression pattern of calmodulin genes under various abiotic and biotic stresses in Indian mustard ().

Unlabelled: Calcium (Ca⁺) as a secondary messenger has a multidimensional role, including the growth and development of plants and the adaptive response to stress conditions. Calmodulin (CaM), a calcium-binding protein, uniquely binds with these Ca⁺ ions and transmits Ca⁺ signals. Calmodulin proteins have been well-reported in various plants for playing a role in abiotic and biotic stress signaling; however, a comprehensive analysis of the genes of Indian mustard () has not been studied much. This study reports their chromosome placements, phylogenetic relations, the presence of protein motifs and -acting elements, and their expression patterns under stress due to salt, heat, cadmium, and . We identified 23 genes coding for eight BjCaM proteins possessing the signature EF-hand domains. Chromosome locations, intron-exon structure, and protein characterization pointed toward genetic diversification. Phylogenetic analysis revealed a close relationship with previously characterized CaM proteins from and rice. -acting elements in the promoter regions suggested the potential role of BjCaM candidates in hormone signaling and various stress-responsive regulatory mechanisms. qRT-PCR analysis showed differential expression patterns, of which and showed higher expression under all stresses. The seven selected genes were sensitive to cadmium stress. Interestingly, despite translating to same protein, , and showed differential expressions under the same stresses. This research represents the first genome-wide analysis of calmodulin genes in Indian mustard, providing a valuable reference for decoding calcium signaling via calmodulin and its potential exploitation to improve crop resistance to stress conditions.

Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-025-01561-x.