Proteome analysis of muscadine grape leaves
Sheikh M Basha1, Ramesh Katam1, Hemanth Vasanthaiah1, Frank Matta2
1Center for Viticulture and Small Fruit Research, Florida A and M University, Tallahassee, FL, USA; 2Plant and Soil Science Department, Mississippi State University, Mississippi State, MS, USA
Abstract: Muscadine grapes are native to the southeastern United States and are used for making wine and consumed as fresh fruit. Grape berries, as ‘sink organs,’ rely on the use of available carbohydrate resources produced by photosynthesis to support their development and composition. A high throughput two-dimensional gel electrophoresis (2-DE) was conducted on muscadine (Vitis rotundifolia) grape leaf proteins to document complexity in their composition and to determine protein identity and function for enhancing photosynthetic efficiency of muscadine grape. 2-DE resolved muscadine leaf proteins into >258 polypeptides with pIs between 3.5 and 8.0 and molecular weight between 12,000 to 15,0000 Daltons. The consistently expressed proteins were excised and subjected to sequencing. Homology search of protein sequences showed 84% identity with Viridi plantae database. Identity of some of these proteins included RuBisCO, glutamine synthetase, pathogenesis-related protein, glyoxisomal malate dehydrogenase, ribonucleoprotein, chloroplast precursor, oxygen evolving enhancer protein. Comparative analysis of 10 muscadine cultivars showed quantitative differences in expression of 39 polypeptides among these genotypes. The results suggested that the polypeptide composition of muscadine grape leaf is complex, and polypeptide number and amount vary widely among muscadine genotypes, and these variations may be responsible for differences in their physiology, berry and stress tolerance characteristics.
Keywords: grapevine, leaves, muscadine, proteins, sequencing, 2-DE