Genome-wide identification, structural characterization and expression profiling of AP2/ERF gene family in bayberry (Myrica rubra)

Bayberry is the most economically significant fruit within the Myricaceae family, having high nutritional and medicinal value. The AP2/ERF family is a class of transcription factors found mainly in plants. However, the bayberry AP2/ERF gene family has not previously been studied. In this study, 113 members of the bayberry AP2/ERF gene family were identified. According to the phylogenetic tree, the members of this group are divided into three subfamilies, namely AP2, ERF, and DREB. The gene structure and conserved motifs were analyzed. Chromosome localization showed that 95 genes were unevenly distributed on 8 chromosomes and 18 genes were located on the skeleton. Gene collinearity analysis of the bayberry AP2/ERF gene family showed 12 segmental duplication events, involving 21 AP2/ERFs. In addition, we further investigated the evolutionary relationship of the AP2/ERF gene family between bayberry and six other species. It was found that bayberry was most closely related to Populus trichocarpa and Malus pumila, with 153 and 141 homologous gene pairs, respectively. Cis-acting elements indicated that AP2/ERFs were related to phytohormone responses, light response, abiotic and biotic stress tolerance. Transcriptomic data showed that the expression pattern of AP2/ERF gene was different in bayberry space electric field treatment and at different stages of fruit development. The results of GO annotation revealed the biological processes, cellular component and molecular function that the AP2/ERF genes were involved. And KEGG enrichment analysis indicated that these genes were mainly clustered in genetic information processing and metabolism pathways. The AP2/ERF gene was identified in the genome of bayberry, and its structure, conserved motif, and phylogenetic relationship were analyzed. These findings of this study serve as a reference for the genome-wide identification of the AP2/ERF gene family in other species and groundwork for future research on the function of AP2/ERF genes in bayberry.