Sugar-Regulated Expression of a Putative Hexose Transport Gene in Grape1
AUTOR(ES)
Atanassova, Rossitza
FONTE
American Society of Plant Biologists
RESUMO
Different lengths of the promoter of grape (Vitis vinifera) VvHT1 (Hexose Transporter 1) gene, which encodes a putative hexose transporter expressed during the ripening of grape, have been transcriptionally fused to the β-glucuronidase reporter gene. In transgenic tobacco (Nicotiana tabacum) transformed with these constructs, VvHT1 promoters were clearly responsible for the sink organ preferential expression. The potential sugar effectors of VvHT1 promoter were studied in tobacco cv Bright-Yellow 2 cells transformed with chimeric constructs. Glucose (56 mm), sucrose (Suc; 58 mm), and the non-transported Suc isomer palatinose doubled the β-glucuronidase activity conferred by the VvHT1 promoter, whereas fructose did not affect it. These effects were the strongest with the 2.4-kb promoter, which contains all putative sugar-responsive elements (activating and repressing), but they were also significant with the 0.3-kb promoter, which contains only activating sugar boxes. The induction of VvHT1 expression by both Suc and palatinose was confirmed in the homologous grape berry cell culture. The data provide the first example of a putative sugar transporter, which is induced by both glucose and Suc in higher plants. Although induction of VvHT1 expression by Suc does not require transport, the presence of glucosyl moiety is necessary for Suc sensing. These results provide new insights into sugar sensing and signaling in plants.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=166812Documentos Relacionados
- Another player joins the complex field of sugar-regulated gene expression in plants
- Cloning and Expression of a Hexose Transporter Gene Expressed during the Ripening of Grape Berry1
- Hexose Transport in Growing Petunia Pollen Tubes and Characterization of a Pollen-Specific, Putative Monosaccharide Transporter1
- Sugar accumulation in grape berries. Cloning of two putative vacuolar invertase cDNAs and their expression in grapevine tissues.
- Developmentally regulated gene from Leishmania encodes a putative membrane transport protein.