PyWRKY40 negatively regulates anthocyanin synthesis in pear fruit.

The deposition of anthocyanin plays a crucial role in fruit pigmentation and serves as the primary determinant of pear quality. Various factors influence the synthesis of anthocyanins, with salicylic acid playing a significant role among them. However, the mechanism by which salicylic acid affects anthocyanin synthesis remains unclear. Our study identifies the transcription factor PyWRKY40 as a pivotal regulator of SA-mediated anthocyanin synthesis in the nucleus. The negative regulatory function of this factor lies in its ability to suppress anthocyanin synthesis, thereby exerting an influence on fruit coloration. We have confirmed the direct binding of PyWRKY40 to the PyDFR promoter through Y1H and EMSA experiments. The findings elucidate a signaling regulatory module, PyWRKY40-PyDFR, which is responsive to SA and enhances fruit pigmentation by modulating anthocyanin metabolism. This insight offers a viable approach to enhancing fruit coloration and improving the overall quality of pear fruits.