Evolutionary dynamics of the cytoskeletal profilin gene family in Brassica juncea L. reveal its roles in silique development and stress resilience

Abstract

Essential to plant adaptation, cell wall (CW) integrity is maintained by CW-biosynthesis genes. Cytoskeletal actin-(de)polymerizing, phospholipid-binding profilin (PRF) proteins play important roles in maintaining cellular homeostasis across kingdoms. However, evolutionary selection of PRF genes and their systematic characterization in family Brassicaceae, especially in Brassica juncea remain unexplored. Here, a comprehensive analysis of genome-wide identification of BjPRFs, their phylogenetic association, genomic localization, gene structure, and transcriptional profiling were performed in an evolutionary framework. Identification of 23 BjPRFs in B. juncea indicated an evolutionary conservation within Brassicaceae. The BjPRFs evolved through paralogous and orthologous gene formation in Brassica genomes. Evolutionary divergence of BjPRFs indicated purifying selection, with nonsynonymous (dN)/synonymous (dS) value of 0.090 for orthologous gene-pairs. Hybrid homology-modeling identified evolutionary distinct and conserved domains in BjPRFs which suggested that these proteins evolved following the divergence of monocot and eudicot plants. RNA-seq profiles of BjPRFs revealed their functional evolution in spatiotemporal manner during plant-development and stress-conditions in diploid/amphidiploid Brassica species. Real-Time PCR experiments in seedling, vegetative, floral and silique tissues of B. juncea suggested their essential roles in systematic plant development. These observations underscore the expansion of BjPRFs in B. juncea, and offer valuable evolutionary insights for exploring cellular mechanisms, and stress resilience.