Systematic identification and analysis of WRKY transcription factors reveals the role of MrWRKY14 in Myrica rubra

Bayberry (<i>Myrica rubra</i>) is a significant subtropical fruit tree, renowned for its distinctive flavor and high nutritional value. WRKY transcription factors are a class of plant-specific zinc-finger proteins that play critical roles in plant growth and development, secondary metabolism, and responses to abiotic stress. However, there is currently limited information about the <i>WRKY</i> gene family in bayberry. This study conducted a systematic bioinformatics analysis of 55 <i>WRKY</i> genes in bayberry, elucidating their phylogenetic relationships, gene structures, conserved motifs, and syntenic characteristics. The results demonstrated that these <i>WRKY</i> family members could be classified into five subfamilies, with each gene containing at least one WRKY domain. The bayberry <i>WRKY</i> genes exhibited significant variations in gene length and intron-exon numbers, while maintaining relatively conserved gene structures within each subfamily. The promoters of <i>WRKY</i> gene members contained multiple regulatory elements, including hormone-responsive elements, light-responsive elements, and abiotic stress-responsive elements. Collinearity analysis revealed that the <i>WRKY</i> family in bayberry experienced six segmental duplication events. Inter-species synteny analysis demonstrated high collinearity between bayberry and <i>Actinidia</i> spp., indicating evolutionary conservation of <i>WRKY</i> genes across different plant species. It was observed that bayberry <i>WRKY</i> genes exhibited significant differential expression across different cultivars and developmental stages of fruits through expression pattern analysis. Further research indicated that MrWRKY14, a member of the bayberry WRKY family, significantly enhanced the promoter activity of <i>MrSWEET1</i>, thereby influencing the process of sugar accumulation. These findings not only provide an important reference for the genome-wide identification of <i>WRKY</i> gene families in plants but also lay a solid foundation for future in-depth functional analysis of bayberry <i>WRKY</i> genes.