Light regulates capsaicinoid biosynthesis via the CaHY5-CaBBX2-CaACS8 module in pepper.

Youxin Yang; Dan Wu; Jiaxin Liu; Ying Luo; Feng Yang; Huiling Zhu; Feng Wang; Ting Yu; Xiaobin Wang; Jinyin Chen; Huibin Han; Yong Zhou

doi:10.1111/nph.71193

PubMed · 42010896

Light regulates capsaicinoid biosynthesis via the CaHY5-CaBBX2-CaACS8 module in pepper.

Youxin Yang·Dan Wu·Jiaxin Liu·Ying Luo·Feng Yang·Huiling Zhu·Feng Wang·Ting Yu·Xiaobin Wang·Jinyin Chen·Huibin Han·Yong Zhou

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Abstract

Capsaicinoids are a class of unique alkaloids that confer the pungent taste to pepper fruits. However, it remains largely unknown how light regulates the biosynthesis of capsaicinoids. We conducted a metabolic analysis on light- and dark-adapted pepper fruits. The results showed that dark-adapted pepper fruits had lower capsaicinoid contents and correspondingly downregulated transcription of capsaicinoid biosynthetic genes (CBGs), indicating that light plays a crucial role in capsaicinoid biosynthesis. Furthermore, silencing of CaHY5, a pivotal transcription factor gene in the light signaling pathway, decreased the content of capsaicinoid and suppressed the expression of CBGs, whereas transient overexpression of CaHY5 generated exactly opposite results. CaHY5 can bind to the G-box motif in the promoters of CaBBX2 and CaACS8, thereby enhancing their transcriptional levels. The activated CaBBX2 then binds to the T/G-box in the CaACS8 promoter to stimulate its expression. CaBBX2 or CaACS8 silencing led to decreased levels of capsaicinoids, while their transient overexpression produced increased capsaicinoid contents. Collectively, our results indicated that the light-activated CaHY5-CaBBX2-CaACS8 regulatory module plays a pivotal role in capsaicinoid biosynthesis. These findings provide new insights into the influence of light on capsaicinoid biosynthesis and potential targets for activation of this biosynthetic pathway in pepper.

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Capsicum Capsaicin Plant Proteins Light Gene Expression Regulation, Plant Promoter Regions, Genetic Gene Silencing Transcription Factors Fruit Biosynthetic Pathways Protein Binding Genes, Plant HY5 capsaicinoid biosynthesis light pepper regulatory module Journal Article

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Youxin Yang, Dan Wu, Jiaxin Liu, Ying Luo, Feng Yang, Huiling Zhu, Feng Wang, Ting Yu, Xiaobin Wang, Jinyin Chen, Huibin Han, Yong Zhou. 2026-04-20. Light regulates capsaicinoid biosynthesis via the CaHY5-CaBBX2-CaACS8 module in pepper.. https://doi.org/10.1111/nph.71193

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