Call for SR&TD Project Grants - 2017
Biosynthesis of secondary compounds in the grape berry: unlocking the role of the plastid
Hernâni Varanda Gerós
Universidade do Minho
Biological Sciences
Agricultural Biotechnology

No items to show...
Grape berries are complex biochemical factories that import, produce or accumulate water, minerals, sugars, phenolics like anthocyanins, and flavor and aroma compounds, which together will translate into wine quality. Plastids are the organelles where phenolic and lipid precursors, carotenoids, and hormones are synthesized, besides being involved in carbon fixation.  The biosynthesis of soluble phenolics begins in the plastids with the aromatic amino acid phenylalanine, a product of the shikimate pathway, with erythrose-4-phosphate and phosphoenolpyruvate being its early precursors. This metabolic plasticity requires an efficient connection between the plastid and the cytosol, which is achieved through the action of membrane transporters of the plastid inner membrane. Thus, the transporter of phosphoenolpyruvate is an important target of investigation. Although the plastid has a pivotal role in plant secondary metabolism, its involvement in the synthesis of aromatic amino acids, carotenoids, lipids and its influence in the synthesis of anthocyanins (in red varieties) remains largely unknown in grapevine. For instance, (1) What are the main metabolites produced in grape berry (white and red) plastids and the main plastid membrane proteins which supply the organelle with precursors? (2) What is the role of the phosphoenolpyruvate transporter VvPPT1? (3) Will its overexpression in tomato boost the accumulation of carotenoids and other quality traits, like aromas? (4) How are specific plastid inner membrane translocators regulated during maturation and affected by hormonal regulation in red and white grapes? (5) How is the metabolism changed in leaf plastids of grapevines infected with Flavescence Doreé that causes overaccumulation of phenolics in leaves? The answer to these and other related questions will promote scientific advances of extreme importance for Plant Science and Biotechnology in general but also, in a longer term, to viticulture. The IR team, in collaboration with leading national and international scientists, is in an excellent position to successfully develop this project, which is tightly linked to the ongoing major research lines and scientific background. The UMinho team has been interested in grapevine source to sink interactions in response to environment and on key biochemical and molecular events of fruit development, ripening and quality, and our previous outputs reflect of our work capacity and dedication to science. In this project it is proposed to take advantage of several plant models, like field-grown berries and leaves, in vitro studies with detached berries and leaves, cultured cells, and transformation of tobacco, Arabidopsis and tomato, and perform a complementary array of omic approaches combined with biochemical, molecular and biotechnological studies, to unlock the role of plastids in the secondary metabolism of grapevine.
Seconday metabolismPlastidGrapevineFruit quality