Genome-wide identification and characterization of GRAS gene family in pigeonpea (Cajanus cajan (L.) Millspaugh)

The GRAS proteins are plant-specific transcription factors (TFs) that play a crucial role in various plant physiological processes, including tissue development and stress responses. To date, GRAS family has been comprehensively characterized in Arabidopsis, soybean, rice, chickpea and other plant species. To understand the structural and functional aspects of pigeonpea (C. cajan), we identified 60 putative GRAS (CcGRAS) genes from pigeonpea genome and further analysed their physicochemical properties, subcellular locations, evolutionary classification, exon–intron structures, conserved domains, gene duplication events and cis-promoter regions. Based on the sequence similarity, CcGRAS family was clustered into 9 subfamilies and the genes with a similar structure and motif distribution were clustered in the same group. The gene duplication studies revealed that these genes were derived from tandem and dispersed duplication events. The cis-promoter regulatory analysis of CcGRAS genes indicated the presence of three types of cis-acting elements including light-responsive, hormone-responsive and plant growth and development related. The expression profiling of CcGRAS genes revealed their tissue-specific functions and differential nature. Collectively, this study highlights relevant functional and regulatory elements of GRAS family in pigeonpea creating a significant resource for future functional studies.