Evolution and Expression Divergence of E2 Gene Family under Multiple Abiotic and Phytohormones Stresses in Brassica rapa.

To understand ubiquitination mechanism, E2s (ubiquitin conjugating enzymes) have crucial part as they play a major role in regulating many biological processes in plants. Meanwhile, Brassica rapa is an important leafy vegetable crop and therefore its characterization along with the expression pattern of E2s under various stresses is imperative. In this study, a total of 83 genes were identified in B. rapa and were classified into four different classes based on domain information. Here, we analyzed phylogenetic relationships, collinear correlation, gene duplication, interacting network, and expression patterns of E2 genes in B. rapa. Furthermore, RT-PCR analysis for 8 multiple abiotic and hormone treatments (namely, ABA, GA, JA, BR, PEG, NaCl, and heat and cold stress) illustrated striking expression pattern under one or more treatments, speculating that these might be stress-responsive genes. The cis-elements and interaction network analyses implicate valuable clues of important function of E2 genes in development and multiple stress responses in B. rapa. This study will further facilitate functional analysis of E2s for improving stress resistance mechanism in B. rapa.