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Article|01 Sep 2023|OPEN
VvBBX44 and VvMYBA1 form a regulatory feedback loop to balance anthocyanin biosynthesis in grape
Wenwen Liu1,2,3,4,6 , Huayuan Mu1,2,3,6 , Ling Yuan5 , Yang Li1,2 , Yuting Li1,2,3 , Shenchang Li1,2,3 , Chong Ren1,2 , Wei Duan1,2 , Peige Fan1,2 , Zhanwu Dai1,2 , Yongfeng Zhou4 , Zhenchang Liang1,2 , Shaohua Li1,2 , Lijun Wang,1,2 ,
1Beijing Key Laboratory of Grape Science and Enology and State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Science, Beijing 100093, China
2China National Botanical Garden, Beijing 100093, China
3University of Chinese Academy of Sciences, Beijing 10049, China
4National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
5Department of Plant and Soil Sciences, Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, Kentucky 40546, USA
6Co-first authors.
*Corresponding author. E-mail:

Horticulture Research 10,
Article number: uhad176 (2023)
Views: 57

Received: 29 Mar 2023
Accepted: 25 Aug 2023
Published online: 01 Sep 2023


Anthocyanins are essential for the quality of perennial horticultural crops, such as grapes. In grapes, ELONGATED HYPOCOTYL 5 (HY5) and MYBA1 are two critical transcription factors that regulate anthocyanin biosynthesis. Our previous work has shown that Vitis vinifera B-box protein 44 (VvBBX44) inhibits anthocyanin synthesis and represses VvHY5 expression in grape calli. However, the regulatory mechanism underlying this regulation was unclear. In this study, we found that loss of VvBBX44 function resulted in increased anthocyanin accumulation in grapevine callus. VvBBX44 directly represses VvMYBA1, which activates VvBBX44. VvMYBA1, but not VvBBX44, directly modulates the expression of grape UDP flavonoid 3-O-glucosyltransferase (VvUFGT). We demonstrated that VvBBX44 represses the transcriptional activation of VvUFGT and VvBBX44 induced by VvMYBA1. However, VvBBX44 and VvMYBA1 did not physically interact in yeast. The application of exogenous anthocyanin stimulated VvBBX44 expression in grapevine suspension cells and tobacco leaves. These findings suggest that VvBBX44 and VvMYBA1 form a transcriptional feedback loop to prevent overaccumulation of anthocyanin and reduce metabolic costs. Our work sheds light on the complex regulatory network that controls anthocyanin biosynthesis in grapevine.