Genome-wide identification and expression analysis of the WRKY gene family in cabbage (Brassica oleracea var. capitata L.)

Abstract

WRKY proteins are a class of transcription factors involved in plant growth and development, biotic and abiotic stress, and other biological processes. In order to systematically study the structure and function of WRKY proteins in cabbage, we used the whole genome sequence of cabbage in the Brassica database (BRAD) and bioinformatics methods. A total of 150 WRKY genes were identified in cabbage, named BolWRKY1-BolWRKY150. These genes were unevenly distributed on 9 chromosomes. In this study, the WRKY proteins were classified into three classes: I, II and III. Cis-acting elements analysis showed that the BolWRKY gene was involved in multiple hormone and stress responses. The protein interaction network analysis suggested that BolWRKY19/100/105 genes might play similar functions in the same stress response. Based on transcriptome data analysis, we found that different BolWRKY genes showed tissue-specific expression. Quantitative real-time PCR analysis showed that several BolWRKY genes were strongly induced by drought stress and ABA (abscisic acid) treatment, indicating members of BolWRKY gene family were closely related to the stress responses such as drought. Our study lays a foundation for further understanding the regulatory mechanism and function of the WRKY gene in response to abiotic stress.