Two-Dimensional Electrophoretic Mapping of Proteins of Bundle Sheath and Mesophyll Cells of the C4 Grass Digitaria sanguinalis (L.) Scop. (Crabgrass)

Two-dimensional electrophoresis was performed on proteins of bundle sheath and mesophyll cells isolated from the C(4) grass Digitaria sanguinalis (L.) Scop. Two-dimensional maps of these proteins were constructed and ribulose-1,5-biphosphate carboxylase and phosphoenolpyruvate carboxylase were identified. Of the total number of proteins found in both cell types, 36% were found only in bundle sheath cells, 17% only in mesophyll cells, and 47% in both cell types. By comparison, the distributions of 48 enzymes assayed in these cell types were 35%, 21%, and 44%, respectively.Protein patterns were also compared with C(4) plants exhibiting different decarboxylation pathways and, in both bundle sheath and mesophyll cells, proteins were found which were unique to each species. Bundle sheath proteins of one C(4) species were found to be more like bundle sheath proteins of another C(4) species than like mesophyll proteins of the same species.