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Journal of Integrative Agriculture  2023, Vol. 22 Issue (4): 1058-1067    DOI: 10.1016/j.jia.2023.03.001
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Isolation and functional analysis of SrMYB1, a direct transcriptional repressor of SrUGT76G1 in Stevia rebaudiana

ZHANG Ting1, 2, ZHANG Yong-xia1, 2, SUN Yu-ming1, 2, XU Xiao-yang1, 2, WANG Yin-jie1, 2, CHONG Xin-ran1, 2, YANG Yong-heng1, 2#, YUAN Hai-yan1, 2#

1 Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-sen), Nanjing 210014, P.R.China

2 Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing 210014, P.R.China

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SrUGT76G1, the most well-studied diterpene glycosyltransferase in Stevia rebaudiana, is key to the biosynthesis of economically important steviol glycosides (SGs).  However, the molecular regulatory mechanism of SrUGT76G1 has rarely been explored.  In this study, we identified a MYB transcription factor, SrMYB1, using a yeast one-hybrid screening assay.  SrMYB1 belongs to the typical R2R3-type MYB protein and is specifically localized in the nucleus with strong transactivation activity.  The transcript of SrMYB1 is predominantly accumulated in flowers, but is also present at a lower level in leaves.  Yeast one-hybrid and electrophoretic mobility shift assays verified that SrMYB1 binds directly to the MYB binding sites in the F4-3 fragment (+50–(–141)) of the SrUGT76G1 promoter.  Furthermore, we found that SrMYB1 could significantly repress the expression of SrUGT76G1 in both epidermal cells of tobacco leaves and stevia callus.  Taken together, our results demonstrate that SrMYB1 is an essential upstream regulator of SrUGT76G1 and provide novel insight into the regulatory network for the SGs metabolic pathway in S. rebaudiana.

Keywords:  Stevia rebaudiana        SrUGT76G1        MYB transcription factor        transcriptional regulation        steviol glycosides  
Received: 22 July 2022   Accepted: 13 January 2023

This work was supported by the National Natural Science Foundation of China (31901597) and the Natural Science Foundation of Jiangsu Province, China (BK20201243).

About author:  ZHANG Ting, E-mail:; #Correspondence YANG Yong-heng, Tel: +86-25-84347086, E-mail:; YUAN Hai-yan, Tel: +86-25-84347086, E-mail:

Cite this article: 

ZHANG Ting, ZHANG Yong-xia, SUN Yu-ming, XU Xiao-yang, WANG Yin-jie, CHONG Xin-ran, YANG Yong-heng and YUAN Hai-yan. 2023.

Isolation and functional analysis of SrMYB1, a direct transcriptional repressor of SrUGT76G1 in Stevia rebaudiana . Journal of Integrative Agriculture, 22(4): 1058-1067.

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