Genome-wide characterization of WRKY genes involved in flavonoid biosynthesis in Erigeron breviscapus

Abstract

Abstract Background The transcription factors of WRKY genes play essential roles in plant growth, stress responses, and metabolite biosynthesis. Erigeron breviscapus, a traditional Chinese herb, is abundant in flavonoids and has been used for centuries to treat cardiovascular and cerebrovascular diseases. However, the WRKY transcription factors that regulate flavonoid biosynthesis in E. breviscapus remain unknown.Results In this study, genome-wide characterization of WRKY genes in E. breviscapus was conducted to predict 75 EbWRKY transcription factors using phylogenetic, gene structure, and conserved motif analyses. In addition, the chromosomal location of each EbWRKY gene was analyzed. RNA sequencing showed that several EbWRKY genes transiently responded to exogenous abscisic acid (ABA), salicylic acid (SA), and gibberellin 3 (GA3) after 4h of treatment. In contrast, the expression of key structural genes involved in flavonoid biosynthesis increased after 4h in GA3 treatment. However, the content of flavonoid metabolites in leaves significantly increased at 12h. The quantitative real-time PCR (qRT-PCR) results showed that the expression patterns of EbWRKY11, EbWRKY30, EbWRKY31, EbWRKY36, and EbWRKY44 transcription factors were similar to those of the 11 structural genes involved in flavonoid biosynthesis.Conclusions This study provides comprehensive information on the regulatory control network of flavonoid accumulation mechanisms, which could contribute to improving the pharmaceutical value of E. breviscapus.