Abstract

Pepper is an important type of vegetable, it was widely cultivated all over the world. The MYB transcription factor family is a key member among them, playing extensive roles in various biological processes such as cell differentiation and stress response in plants. In this study, a MYB family member, CcMYB1R1 , was successfully cloned from the 'Shuanla' pepper. Subcellular localization confirmed that CcMYB1R1 is localized in the nucleus. Expression pattern analysis revealed that the level of CcMYB1R1 gradually increased during fruit development. Functional analysis demonstrated that silencing CcMYB1R1 led to a significant decrease in both capsaicinoids content and the expression of key biosynthetic genes, whereas its transient overexpression exhibited the opposite effect. Y1H and EMSA assays revealed that CcMYB1R1 binds to the promoters of CcCOMT and CcHCT, while LUC assays further demonstrated that CcMYB1R1 activates CcCOMT transcription. In summary, CcMYB1R1 functions as a regulatory factor in the capsaicinoids biosynthetic pathway by directly targeting downstream structural genes, thereby playing a crucial role in regulating capsaicinoids accumulation. This study provides a foundational theory for the molecular breeding and regulation of capsaicinoids content in pepper fruits.