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Article|01 Oct 2020|OPEN
Coexpression network analysis reveals an MYB transcriptional activator involved in capsaicinoid biosynthesis in hot peppers
Binmei Sun1, Xin Zhou1,2, Changming Chen1, Chengjie Chen1, Kunhao Chen3,4, Muxi Chen3,4, Shaoqun Liu1, Guoju Chen1, Bihao Cao1, Fanrong Cao1, Jianjun Lei1,5, & Zhangsheng Zhu1,6,
1Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, College of Horticulture, South China Agricultural University, Guangzhou 510642, China
2Jiangxi Agricultural Engineering College, Zhangshu 331200 Jiangxi, China
3Guangdong Helinong Seeds, Co., Ltd., Shantou 515800 Guangdong, China
4Guangdong Helinong Agricultural Research Institute, Co., Ltd., Shantou 515800 Guangdong, China
5Henry School of Agricultural Science and Engineering, Shaoguan University, Guangdong 512005, China
6Peking University—Southern University of Science and Technology Joint Institute of Plant and Food Sciences, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China

Horticulture Research 7,
Article number: 20162 (2020)
doi: 10.1038/hortres.2020.162
Views: 95

Received: 06 Mar 2020
Revised: 18 Jun 2020
Accepted: 13 Jul 2020
Published online: 01 Oct 2020

Abstract

Plant biosynthesis involves numerous specialized metabolites with diverse chemical natures and biological activities. The biosynthesis of metabolites often exclusively occurs in response to tissue-specific combinatorial developmental cues that are controlled at the transcriptional level. Capsaicinoids are a group of specialized metabolites that confer a pungent flavor to pepper fruits. Capsaicinoid biosynthesis occurs in the fruit placenta and combines its developmental cues. Although the capsaicinoid biosynthetic pathway has been largely characterized, the regulatory mechanisms that control capsaicinoid metabolism have not been fully elucidated. In this study, we combined fruit placenta transcriptome data with weighted gene coexpression network analysis (WGCNA) to generate coexpression networks. A capsaicinoid-related gene module was identified in which the MYB transcription factor CaMYB48 plays a critical role in regulating capsaicinoid in pepper. Capsaicinoid biosynthetic gene (CBG) and CaMYB48 expression primarily occurs in the placenta and is consistent with capsaicinoid biosynthesis. CaMYB48 encodes a nucleus-localized protein that primarily functions as a transcriptional activator through its C-terminal activation motif. CaMYB48 regulates capsaicinoid biosynthesis by directly regulating the expression of CBGs, including AT3a and KasIa. Taken together, the results of this study indicate ways to generate robust networks optimized for the mining of CBG-related regulators, establishing a foundation for future research elucidating capsaicinoid regulation.