The CaHY5-CaNAC83 regulatory pathway positively regulates anthocyanin biosynthesis in pepper

Anthocyanins are major pigments responsible for the purple coloration of pepper fruits and confer significant nutritional value, and light signal is known to induce anthocyanin synthesis and accumulation. In this study, a NAC family member, CaNAC83 , was successfully cloned the purple pepper, and quantitative real-time PCR analysis revealed that CaNAC83 is predominantly expressed in pepper fruits and flowers, with expression levels increasing during early fruit development and then decreasing, peaking at 35 days post-anthesis. The function of CaNAC83 was validated using transient silencing and overexpression assays in pepper seedlings and detached fruits, transient silencing of CaNAC83 led to decreased anthocyanin content and down-regulated expression of structural genes involved in the anthocyanin biosynthetic pathway. Conversely, transient overexpression of CaNAC83 significantly increased both anthocyanin accumulation and the expression of structural genes. The result demonstrated that CaNAC83 directly binds to the promoters of Ca4CL and CaF3H and activates their expression, thereby promoting anthocyanin accumulation in pepper fruits and leaves. Furthermore, CaNAC83 was shown to be targeted and activated by the light-responsive factor CaHY5. Collectively, these results indicate that CaNAC83 positively regulates anthocyanin biosynthesis in pepper, and these findings may offer implications for future purple‑pepper molecular breeding.