Anthocyanin Accumulation and Transcriptional Regulation of Anthocyanin Biosynthesis in Purple Pepper

Pepper (Capsicum annuum) is among the important horticultural crops with economic value, and more and more colorful varieties have been marketed. The purple pepper is becoming increasingly popular on the consumer market because of its anthocyanin richness. Here, two cyanidin-based anthocyanins were separated and identified from peels of purple cultivars by HPLC–LC–MS. To study the molecular mechanism of anthocyanin accumulation, the differential expression of genes related to anthocyanin biosynthesis was examined by qRT-PCR and RNA-Seq in peel from green and purple cultivars. These results show that CaANT1, CaANT2, CaAN1, and CaTTG1 are involved in anthocyanin accumulation of pepper. Further investigation suggested that CaANT1, CaANT2, CaAN1, and CaTTG1 can activate anthocyanin accumulation via forming a new MMBW transcription complex.