Molecular analysis of effects of environment on wheat flour quality and allergenic potential
Location: Crop Improvement & Utilization Research
Title: Differential effects of a post-anthesis fertilizer regimen on the wheat flour proteome determined by quantitative 2-DE
Submitted to: Proteome Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2011
Publication Date: August 4, 2011
Citation: Altenbach, S.B., Tanaka, C.K., Hurkman Ii, W.J., Whitehand, L.C., Vensel, W.H., Dupont, F.M. 2011. Differential effects of a post-anthesis fertilizer regimen on the wheat flour proteome determined by quantitative 2-DE. Proteome Science. 9:46.
Interpretive Summary: The timing, amount and form of fertilizer applications can alter not only wheat grain yield and protein content, but also affect protein composition. As a result, functional properties, nutritional quality and the levels of immune-reactive proteins in wheat flour may be altered. To better understand the effects of fertilizer on the accumulation of individual flour proteins, a greenhouse study was performed in which wheat plants were either supplied with fertilizer or grown without fertilizer during the period of grain development. Proteins were extracted from flour produced from the plants and the effect of fertilizer on the proportions of more than 200 individual proteins in the flour was measured. Proteins that showed the greatest response to fertilizer were identified. This information is essential for predicting the effects of agronomic inputs on wheat flour composition and quality for developing strategies to produce new wheat cultivars that will have consistent flour quality when grown in different locations and years.
Mineral nutrition during wheat grain development has large effects on wheat flour protein content and composition, which affect the mixing, baking and nutritional quality of a commodity of great economic value. However, it has been difficult to link individual proteins to specific genes in order to define the precise effects of mineral nutrition on gene expression and protein accumulation. Plants of Triticum aestivum ‘Butte 86’ were grown with or without post-anthesis fertilization (PAF) with nitrogen, potassium and phosphorus (NPK). Flour protein content increased from 7 to 14% with PAF and most protein types increased in terms of ug/mg flour protein. However, flour N increased more than S. Use of an improved 2-DE MS/MS analysis made it possible to document changes in 157 unique proteins that accounted for up to 93% of flour protein. Proportions of many proteins changed with PAF according to their content of the sulfur-containing amino acids Cys + Met. The low-S omega-gliadins and the low-to-medium-S high molecular weight-glutenin subunits (HMW-GS), alpha-gliadins and serpins increased with PAF, whereas the medium-S low molecular weight-glutenin subunits (LMW-GS), gamma-gliadins and triticins did not change greatly, and the high-S amylase/protease inhibitors, farinins, and purinins decreased. Total glutenin remained at 34 to 35%, but the ratio of LMW-GS to HMW-GS decreased from 1.7 to 1.1 and the ratio of gliadins to glutenin subunits increased from 1.0 to 1.3. The identified proteins increased from 90% to 93% of normalized spot volume (SV) with PAF, whereas minor unidentified proteins accounted for a larger percentage of SV without PAF. This is the first study of the effects of mineral nutrition on flour composition in which the majority of the individual flour proteins were identified based on their unique sequences and then quantified. The ability to measure changes in accumulation for the whole array of flour proteins may lead to improved strategies to breed for stability of protein composition and to predict the effects of agronomic inputs on flour composition and flour quality.