AUTHOR=Ren Ruihua , Yue Xiaofeng , Li Junnan , Xie Sha , Guo Shuihuan , Zhang Zhenwen 

TITLE=Coexpression of Sucrose Synthase and the SWEET Transporter, Which Are Associated With Sugar Hydrolysis and Transport, Respectively, Increases the Hexose Content in Vitis vinifera L. Grape Berries

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00321

DOI=10.3389/fpls.2020.00321

ISSN=1664-462X

ABSTRACT=<p>The sugar content of grape berries is affected by many factors. To explore the hexose content in different cultivars, the photosynthesis, vegetative, and reproductive biomass, as well as the enzyme activities and expression levels of genes related to sugar metabolism and sugar contents were measured. Samples were collected 70–110 days after anthesis (DAA), from Riesling (RI), Petit Manseng (PM), and Cabernet Sauvignon (CS) berries cultivated in the field. The results indicated that high expression levels of VvSWEET<italic>15</italic> and <italic>VvSS3</italic> and a high activity of sucrose synthase (SS) are associated with a higher hexose content in the berries of PM than in the berries of the other two cultivars. These genes promoted hexose accumulation in the berries by regulating sugar hydrolysis and transport. The results of this study indicate that active sugar hydrolysis and transport increase the hexose content of PM berries, which provides insights for grape berry quality improvement and breeding projects in wine production.</p><p><bold>Main Conclusion:</bold> The active <italic>VvSS3</italic>, sucrose synthase (SS), and <italic>VvSWEET15</italic> increases the hexose content in Petit Manseng berries, which are associated with sugar hydrolysis and transport.</p>