MYB24 Negatively Regulates the Biosynthesis of Lignin and Capsaicin by Affecting the Expression of Key Genes in the Phenylpropanoid Metabolism Pathway in Capsicum chinense

• Published in: Molecules (Basel, Switzerland) Switzerland), 2023-03, Vol.28 (6), p.2644
• Main Authors: Yu, Shuang, Zhang, Wei, Zhang, Liping, Wu, Dan, Sun, Peixia, Huang, Chuang, Fu, Genying, Deng, Qin, Wang, Zhiwei, Cheng, Shanhan
• Format: Article
• Language: English
• Subjects: Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Biosynthesis; Capsaicin; Capsaicin - metabolism; Capsicum - metabolism; Catalysis; CCR1 protein; Fatty acids; Female; Flavonoids; Flowering; Fruit - chemistry; Fruits; Gene expression; Gene Expression Regulation, Plant; Genes; Genetic transformation; Humans; Lignin; Lignin - metabolism; Metabolism; Metabolites; MYB24 transcription factor; phenylpropanoid metabolism; Placenta - metabolism; Pregnancy; pungency regulation; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Transcriptomes; Transgenic plants; Vegetables
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28062644

The wide application of pepper is mostly related to the content of capsaicin, and phenylpropanoid metabolism and its branch pathways may play an important role in the biosynthesis of capsaicin. The expression level of MYB24, a transcription factor screened from the transcriptome data of the pepper fruit development stage, was closely related to the spicy taste. In this experiment, was cloned from Hainan Huangdenglong pepper, a hot aromatic pepper variety popular in the world for processing, and its function was confirmed by tissue expression characteristics, heterologous transformation in , and VIGS technology. The results showed that the relative expression level of was stable in the early stage of pepper fruit development, and increased significantly from 30 to 50 days after flowering. Heterologous expression led to a significant increase in the expression of and decrease in lignin content in transgenic plants. silencing led to a significant increase in the expression of phenylpropanoid metabolism pathway genes , , and ; lignin branch and ; and capsaicin pathway , , and genes in the placenta of pepper, with capsaicin content increased by more than 31.72% and lignin content increased by 20.78%. However, the expression of , , , , etc., in the corresponding pericarps did not change significantly. Although , , and increased significantly, the relative expression amount was smaller than that in placental tissue, and the lignin content did not change significantly. As indicated above, may negatively regulate the formation of capsaicin and lignin by regulating the expression of genes from phenylpropanoid metabolism and its branch pathways.