Transcriptome sequencing of the pericarp of three different color-transition red peppers during the development and ripening processes.

Exploration of genes related to regulating ripening and carotenoid biosynthesis in pepper fruit pericarp. We identified the MADS-box transcription factor RIPENING INHIBITOR (MADS-RIN) in pepper (Capsicum annuum), which regulates ripening in climacteric tomato (Solanum lycopersicum) fruits, using weighted gene co-expression network analysis (WGCNA). We found MADS-RIN can directly bind to the promoters of carotenoid biosynthetic genes phytoene synthase 1 (PSY1) and capsanthin/capsorubin synthase (CCS) and the promoter of DIVARICATA1 to activate their expression, thereby regulating carotenoid biosynthesis directly or indirectly. The physical interaction between MADS-RIN and DIVARICATA1 enhances the transactivation effect on PSY1 and CCS. The self-transactivation of MADS-RIN demonstrates its capability to expedite the above process under specific conditions.