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Article|22 Nov 2022|OPEN
Vacuolar Phosphate Transporter1 (VPT1) may transport sugar in response to soluble sugar status of grape fruits 
Qian Bai1,2 ,† , Xuexue Chen1 ,† , Zhenzhen Zheng1 ,† , Jinjing Feng1 , Yanjun Zhang1 and Yuanyue Shen1 , Yun Huang,1 ,
1Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
2Ministry of Education Key Laboratory of Silviculture and Conservation, College of Forestry, Beijing Forestry University, 35 East Qinghua Road, Beijing 100083, China
*Corresponding author. E-mail: yunhuang@bua.edu.cn
Qian Bai and Xuexue Chen,Zhenzhen Zheng contributed equally to the study.

Horticulture Research 10,
Article number: uhac260 (2023)
doi: https://doi.org/10.1093/hr/uhac260
Views: 222

Received: 19 Jul 2022
Accepted: 17 Nov 2022
Published online: 22 Nov 2022

Abstract

Vacuolar Phosphate Transporter1 (VPT1)-mediated phosphate uptake in the vacuoles is essential to plant development and fruit ripening. Interestingly, here we find that the VPT1 may transport sugar in response to soluble sugar status of fruits. The VvVPT1 protein isolated from grape (Vitis vinifera) berries was tonoplast-localized and contains SPX (Syg1/Pho81/XPR1) and MFS (major facilitator superfamily) domains. Its mRNA expression was significantly increased during fruit ripening and induced by sucrose. Functional analyses based on transient transgenic systems in grape berry showed that VvVPT1 positively regulated berry ripening and significantly affected hexose contents, fruit firmness, and ripening-related gene expression. The VPT1 proteins (Grape VvVPT1, strawberry FaVPT1, and Arabidopsis AtVPT1) all showed low affinity for phosphate verified in yeast system, while they appear different in sugar transport capacity, consistent with fruit sugar status. Thus, our findings reveal a role for VPT1 in fruit ripening, associated to its SPX and MFS domains in direct transport of soluble sugar available into the vacuole, and open potential avenues for genetic improvement in fleshy fruit.