Ubiquitination of the PpMADS2 transcription factor controls linalool production during UV-B irradiation in detached peach fruit

Abstract

Plant secondary metabolites undergo changes in response to UV-B irradiation. Although UV-B irradiation reduces flavor-associated volatile compounds in detached peach (Prunus persica L. Batsch) fruit, the underlying regulatory mechanisms remain unclear. By integrating proteomic, transcriptomic and metabolomic data from peach fruit following UV-B irradiation, we discovered that the detached fruit responds to UV-B by suppressing the biosynthesis of the flavor-related monoterpene linalool. We identified PpMADS2, a transcription factor that regulates linalool biosynthesis by activating terpene synthase 1 (PpTPS1) expression. PpMADS2 overexpression in peach and tomato fruits significantly increased linalool levels compared to the controls. Proteomic data and immunoblots revealed a decrease in PpMADS2 abundance following exposure to UV-B. Moreover, our results demonstrated that PpMADS2 interacts with the E3 ubiquitin ligase PpCOP1 both in vitro and in vivo. The UV-B induced 26S-proteasome-mediated degradation of PpMADS2 is largely PpCOP1-dependent. Taken together, our findings demonstrate that linalool biosynthesis in detached peach fruit exposed to UV-B radiation is governed by the PpCOP1–PpMADS2–PpTPS1 module. This study enhances our understanding of the interplay between light signaling and fruit flavor quality. Multi-omics approaches offer valuable resources for investigating the mechanisms underlying how light influences metabolism in fruit crops.