Objective To identify and analyze the expression of R2R3-MYB transcription factor family of Bupleurum chinense, and provide a theoretical basis for analyzing the secondary metabolic regulation mechanism of B. chinense under salt stress. Methods All R2R3-MYB genes of B. chinense were screened and identified by homologous alignment and hidden Markov model. Their physical and chemical properties, phylogenetic relationship, conserved domains, gene structure, cis-acting elements and chromosome distribution were systematically analyzed, and their expression patterns under 200 mmol/L salt stress were analyzed by transcriptome sequencing. Results A total of 116 R2R3-MYB transcription factors were identified in the B. chinense genome, all of which were hydrophilic nuclear localization proteins, with only two members containing transmembrane domains. Phylogenetic analysis showed that they clustered into 23 subfamilies, mainly distributed in K, P, W, and X subfamilies. The promoters contained four types of cis-acting elements, including light response, hormone response, stress response, and development regulation, among which light response elements accounted for the highest proportion. There were 42 pairs of gene duplication events, including three tandem duplications and 39 fragment duplications. The salt stress expression profile revealed that 21 genes responded significantly, and they were classified into early response type, mid-term continuous type, and late inhibition type according to the expression patterns. Conclusion This study conducted a genome-wide identification, evolutionary analysis and salt stress expression analysis of the R2R3-MYB gene family in B. chinense. It was initially determined that BcMYB59 and BcMYB116, due to their unique structural features and strong stress response, are excellent candidate genes for understanding the salt stress response mechanism and potential transmembrane signal perception function of B. chinense.

Bupleurum chinense DC.  /  transcription factor  /  R2R3-MYB  /  bioinformatics  /  salt stress