|Hurkman Ii, William|
Submitted to: Encyclopedia of Diagnostic Genomics and Proteomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2004
Publication Date: 6/1/2005
Citation: Vensel, W.H., Tanaka, C.K., Cal, N., Wong, J.H., Buchanan, B.B., Hurkman, W.J. 2005. Developmental changes in the metabolic protein profiles of wheat endosperm. Encyclopedia of Diagnostic Genomics and Proteomics.78:53-61 Interpretive Summary: Proteins are fundamental to all cellular processes in the plant cell. Proteomics, the study of proteins on a large scale, was used to identify the many proteins in the endosperm of the developing wheat grain. Proteins were separated by charge and size using polyacrylamide gel electrophoresis. Individual proteins were analyzed by mass spectrometry and identified using computer database comparisons. Over 250 proteins of wheat endosperm were identified that function in thirteen cellular processes. This information, together with analyses of early and late stages of endosperm development, provides a dynamic picture of events that accompany grain development. Carbohydrate metabolism, protein synthesis/assembly, transcription/translation, stress/defense, nitrogen metabolism, and protein turnover are the principal functions early in development. Stress/defense, protein storage, and carbohydrate metabolism are the principle functions late in development. In summary, there was a shift from active biosynthesis and metabolism to maintenance and storage as the grain matured. In this study, not only a picture of the dynamic processes taking place during grain maturation was obtained, but also reference maps of the developing endosperm proteome. With the formulation of these maps, the stage is set for elucidating further details on the effect of environmental conditions on grain-fill and on the composition and quality of mature grain.
Technical Abstract: A combined two-dimensional gel electrophoresis/mass spectrometry approach was utilized to identify over 250 proteins of wheat (Triticum aestivum L., cv Butte 86) starchy endosperm that participate in thirteen biochemical processes: ATP interconversion reactions, carbohydrate metabolism, cell division, cytoskeleton, lipid metabolism, nitrogen metabolism, protein synthesis/assembly, protein turnover, signal transduction, protein storage, stress/defense, transcription/translation and transport. Endosperm protein populations were compared at early (10 days post-anthesis, dpa) and late (36 dpa) stages of grain development. Analysis of protein number and spot volume revealed that carbohydrate metabolism, transcription/translation, and protein synthesis/assembly were the principal endosperm functions at 10 dpa followed by nitrogen metabolism, protein turnover, cytoskeleton, cell division, signal transduction, and lipid metabolism. Carbohydrate metabolism and protein synthesis/assembly were also major functions at 36 dpa, but stress/defense and storage were predominant. The results provide insight into biochemical events taking place during wheat grain development and highlight the value of proteomics in characterizing complex biochemical processes. Further, the proteome maps will facilitate future studies addressing the effects of genetic and environmental factors on the development and quality of wheat grain.