As one of the largest gene families in plants, MYB family plays an important role in plant growth and fruit development. This study would identify the members of the R2R3-MYB subfamily of Chinese jujube and analyze their bioinformatics and expression patterns, aiming to provide the reference for further exploring their function in jujube growth, especially in fruit development.

The R2R3-MYB genes of Arabidopsis thaliana were used as probes, and this subfamily members in the jujube genome were screened out by BLAST and HMMER. Based on the Plant Transcription Factors Database, Uniprot, Gcorn Plant and other databases, R2R3-MYB genes were analyzed by MEGA-X, ExPASy, TBtools, and PheatMap. Transcriptome data and real-time quantitative PCR (qRT-PCR) were used to evaluate the expression of these genes, and the interaction proteins of key candidate proteins were predicted and verified.

In this study, 118 R2R3-MYB subfamily members were identified in jujube genome, all of which had a typical MYB domain. They were divided into 18 subgroups, named ZjMYB1-ZjMYB118. The number of amino acids encoded by the genes ranged from 200 to 400. Among them, 95 genes were located on 12 chromosomes, and which on Chr. 4 was the most widely distributed. The phylogenetic analysis showed that orthologous and paralogous events occurred during the evolution of these genes. By transcriptomic and qRT-PCR analysis, some R2R3-MYB genes were involved in the fruit development. In particular, ZjMYB59 and ZjMYB104 might participate in fruit enlargement and color development. Protein interaction prediction and yeast two-hybrid test confirmed that ZjMYB104 and ZjMPK3 were interacted each other.

118 members of the R2R3-MYB subfamily members were identified and distributed on 12 chromosomes. The structure of these subfamily members was highly conservative. The orthologous and paralogous events occurred in jujube genome evolution and the candidate genes closely related to fruit development were screened out. This study provided clues and references for further functional analysis of R2R3-MYB subfamily in jujube.