Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 13, 2008
Publication Date: January 1, 2009
Citation: Hurkman II, W.J., Vensel, W.H., Tanaka, C.K., Whitehand, L.C., Altenbach, S.B. 2009. Effect of High Temperature on Albumin and Globulin Accumulation in the Endosperm Proteome of the Developing Wheat Grain. Journal of Cereal Science. 49:12-23. Interpretive Summary: High temperature during grain fill is one of the most significant factors that affects wheat yield and flour quality. In this study, the effect of high temperature during grain fill on nearly 200 wheat endosperm protein accumulation profiles was investigated. These profiles revealed that protein function shifted from carbohydrate metabolism, protein synthesis/assembly, stress/defense and transcription/translation early in development to stress/defense mid development, and then to stress/defense and storage late in development. In summary, there was a shift from active biosynthesis and metabolism to maintenance and storage as the grain matured. The relative timing of endosperm functions during development was similar for the three temperature regimens, but grain size was smaller and protein amount lower under the high temperature regimens. A number of proteins were affected in the mature grain by the high temperature regimens, including known allergens and proteins that may have a role in flour quality. This comprehensive study provides a picture of the dynamic processes taking place during grain maturation and provides new insights into the effect of high temperature on the composition and quality of the mature grain.
Technical Abstract: The effect of high temperature during grain fill on albumin and globulin accumulation profiles was investigated in the endosperm of developing wheat (Triticum aestivum, L. cv. Butte 86) grain. Albumins and globulins were isolated from endosperm of grain grown under a moderate (24°C/17°C, day/night) or a high temperature regimen (38°C/28°C) imposed at 10 or 20 days post anthesis (dpa). Maximum grain fresh weight and albumin and globulin amount peaked earlier, but at lower levels under the high temperature regimens. The relative timing of endosperm functions during development was similar for the three temperature regimens. Protein function shifted from carbohydrate metabolism, protein synthesis/assembly, stress/defense and transcription/translation early in development to stress/defense mid development, and then to stress/defense and storage late in development. When plants were transferred from the moderate to the high temperature regimen at 10 dpa, HSP 70, 11S legumin-like protein, triosephosphate isomerase, HSP16.9, and endosperm globulins increased and ADP glucose pyrophosphorylase decreased transiently. Under the high temperature regimen initiated at 20 dpa, triticin and HSP 70 increased transiently. In addition, a number of proteins increased or decreased in the mature grain under both regimens, including foam-forming proteins that may have a role in stabilizing gas bubbles in dough and known allergens.