Study On Function Of Sucrose Transporters VvSUC11、VvSUC12in Improving The Sugar Yields Of Sugar Beet

Objective: Sugar beet is an important sugar crop in the world. The sucrose content in roots is the keydeterminant of sugar beet quality. In order to study sucrose transporter protein can improve the saccharinityof sugar beet, two sucrose transporter genes from grape, VvSUC11and VvSUC12, were introduced intosugar beet root using plant genetic engineering. The work laid the foundation for using sucrose transportergenes to increase crop yield and quality.Method: A bivalent root specific expression vector called pCAMBIA2301-SP1-VvSUC11-SP2-VvSUC12containing grape sucrose transporters VvSUC11and VvSUC12genes was constructed and transformed intosugar beet varieties KWS-9103by Agrobacterium tumefaciens mediated transformation. Then PCR andRT-PCR analysis were used to confirm the integration and expression of the two genes in transgenetic sugarbeets. The leaf characters, physiological targets, tuberous root weight and saccharinity of transgenic andcontrol plants were measured after transplanting to the field.Result:Thirteen transgenetic sugar beet lines were obtained by PCR and RT-PCR analysis. The resultsindicated that the average number of leaf width, petiole length and leaf number of transgenic plants were19.31cm,29.17cm and38.33, which increased obviously by31.81%,16.61%and,17.04%respectively,the average number of leaf length were25.16cm, which increased insignificantly by1.68%. However,there were no significant difference in the content of Chlorophyll a（1.31mg·g-1）, Chlorophyll b（0.562mg·g-1） and total Chlorophyl（l1.87mg·g-1） between transgenic and control plants. Compared to control,soluble sugar content (14.59mg·g-1) of leaf was reduced markedly by13.04%, but soluble sugar content(21.90mg·g-1) of petiole was only increased by3.36%. The average root weight and sugar content ofindividual plants were3.067kg and183.2g·kg-1, respectively. Compared with control plants, the rootweight of transgenic plants increased by5.91%, while saccharinity increased significantly by9.41%. Theseresults demonstrated that larger leaves and higher leaf number, lead to the expansion of photosynthetic leafarea, and shorter petiole in transgenic sugar beets were not only helpful for accelerated the rate of transportof sugar molecules from the source leaves to the sink, but also the formation of tuberous root and theaccumulation of sugar.Conclusion: The sugar transporters VvSUC11and VvSUC12genes transformation could effectivelyimprove saccharinity in transgenic sugar beet.