A R2R3-MYB transcriptional activator LmMYB15 regulates chlorogenic acid biosynthesis and phenylpropanoid metabolism in Lonicera macranthoides. (July 2021)

• Record Type: Journal Article
• Authors: Tang, Ning; Cao, Zhengyan; Yang, Cheng; Ran, Dongsheng; Wu, Peiyin; Gao, Hongmei; He, Na; Liu, Guohua; Chen, Zexiong
• Is Part Of: Plant science. Volume 308(2021)
• Publication Date: 2021-07
• Subjects: Lonicera macranthoides -- Chlorogenic acid biosynthesis -- LmMYB15 -- Transcriptional activator -- DAP-Seq; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2021.110924
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: LmMYB15 is a R2R3-MYB transcription factor and acts as a transcriptional activator. Overexpression of LmMYB15 in tobacco led to increased chlorogenic acid accumulation. DAP-Seq identified the direct downstream targets of LmMYB15. LmMYB15 functions via binding and activating the promoters of 4CL, MYB3 and MYB4. Abstract: Lonicera macranthoides Hand-Mazz is an important medicinal plant widely distributed in southern China that has long been used in Chinese traditional medicines. Chlorogenic acid (CGA, 3-caffeoylquinic acid) is the major biologically active ingredient in L. macranthoides . Although key CGA biosynthetic genes have been well documented, their transcriptional regulation remains largely unknown. In this study, we observed that a R2R3 MYB transcription factor LmMYB15 showed a significant correlation with CGA content, indicating its potential role in CGA biosynthesis. A yeast two-hybrid assay suggested that LmMYB15 functions as a transcriptional activator. Overexpression of LmMYB15 in tobacco led to increased accumulation of CGA compared to those in wild-type leaves. To elucidate its functional mechanism, genome-wide DAP-seq was employed and identified the conserved binding motifs of LmMYB15, that is [(C/T) (C/T) (C/T) ACCTA(C/A) (C/T) (A/T)], as well as its direct downstream target genes, including 4CL, MYB3, MYB4, KNAT6/7, IAA26, and ETR2 . Subsequently, yeast one-hybrid and dual-luciferase reporter assays verified that LmMYB15 could bind and activate the promoters of 4CL, MYB3 and MYB4, thereby facilitating CGA biosynthesis and phenylpropanoid metabolism. Our findings provide a new track for breeding strategies aiming to enhance CGA content in L. macranthoides that can significantly contribute to better mechanical properties.