The transcription factor CaBBX10 promotes chlorophyll and carotenoid pigment accumulation in Capsicum annuum fruit.

This article focuses on the role of the transcription factor CaBBX10 in promoting the accumulation of chlorophyll and carotenoid pigments in Capsicum annuum (pepper) fruit. The study demonstrates that CaBBX10 directly binds to the promoters of CaCHLD and CaPSY1, which encode key rate-limiting enzymes in chlorophyll and carotenoid biosynthesis pathways, respectively, thereby activating their expression. Functional analyses through virus-induced gene silencing in pepper and overexpression in tomato confirmed that CaBBX10 enhances pigment accumulation and chloroplast development. Additionally, CaBBX10 physically interacts with the photomorphogenic factor CaCOP1, which mediates its ubiquitination and degradation, linking pigment biosynthesis regulation to light signaling. These findings elucidate a coordinated transcriptional mechanism underlying simultaneous chlorophyll and carotenoid biosynthesis in pepper fruit, with implications for improving pigment content in horticultural crops.