Genome-Wide Identification of Gene Family and Functional Characterization of in .

Pepper is renowned worldwide for its distinctive spicy flavor. While the gene expression characteristics of the capsaicinoid biosynthesis pathway have been extensively studied, there are already a few reports regarding transcriptional regulation in capsaicin biosynthesis. In this study, 73 were identified in the genome of , and their physicochemical traits, DNA, and protein sequence characteristics were found to be complex. Combining RNA-seq and qRT-PCR data, the transcription factor , which was associated with the accumulation tendency of capsaicinoid, was screened and named . was highly expressed in the placenta of spicy peppers. The heterologous expression of in promoted the expression of genes , , , , , and and led to the accumulation of lignin and flavonoids. Furthermore, the expression of the capsaicinoid biosynthesis pathway genes (CBGs) , , and was significantly reduced in -silenced pepper plants, resulting in a decrease in the amount of capsaicin. However, there was no noticeable difference in lignin accumulation. The findings suggested that could be involved in regulating capsaicinoid synthesis by promoting the expression of genes upstream of the phenylpropanoid pathway and inhibiting CBGs' expression. Moreover, the results highlighted the role of in controlling the pungency of pepper and suggested that the competitive relationship between lignin and capsaicin could also regulate the spiciness of the pepper.