WRKY transcription factor MdWRKY71 regulates flowering time in apple.

In plants, flowering is crucial to reproductive success. Receiving limited attention in apple research is the function of WRKY transcription factors in regulating flowering time. We characterized a WRKY transcription factor, MdWRKY71, from red-fleshed apple in this study, and ectopically expressed it in Arabidopsis thaliana, which revealed its role in flowering. The sequence of MdWRKY71 exhibited similarity to that of AtWRKY71, and its protein comprised a WRKY domain and a CH zinc finger-like motif, placing it within subgroup IIc of the WRKY family. The similar changing trends demonstrated a significant positive correlation between the expression level of MdWRKY71 and the key flower transition genes in apical buds of apple in flower transition stage. Overexpression of MdWRKY71 promoted the upregulation of certain flower transition genes in apple calli. The ectopic expression of MdWRKY71 in A. thaliana was observed to induce early flowering. Additionally, MdWRKY71 could bind to the promoters of several floral pathway integrators directly and interact with them to enhance their expression levels. These results contribute to our understanding of the molecular mechanism through which MdWRKY71 regulates the flowering process in fruit trees, such as red-fleshed apple.