HMW-GS composition and rye translocations of U.S. eastern soft winter wheat and their associations with protein strength

Authors: MA, FENGYUN - The Ohio State University; KIM, JIEUN - The Ohio State University; CHO, EUNJIN - The Ohio State University; Brown-Guedira, Gina; PARK, CHUL SOO - Chonbuk National University; Baik, Byung-Kee

Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/4/2019
Publication Date: 7/5/2019
Citation: Ma, F., Kim, J., Cho, E., Brown Guedira, G.L., Park, C., Baik, B.V. 2019. HMW-GS composition and rye translocations of U.S. eastern soft winter wheat and their associations with protein strength. Journal of Cereal Science. https://doi.org/10.1016/j.jcs.2019.102799.
DOI: https://doi.org/10.1016/j.jcs.2019.102799

Interpretive Summary: The amount and type of protein molecules present in wheat grain have a considerable influence on the food processing and product qualities of milled flour. Among these protein molecules, high molecular weight glutenin subunits (HMW-GSs) are known to play a key role in determining protein strength and are largely responsible for the differences in protein strength among wheat varieties. The HMW-GS composition of hard wheat grain desirable for making bread has been identified and is widely used for the selection of breeding lines in the development of hard wheat varieties. U.S. soft wheat flour is generally used for making cookies, pancakes, cakes and several other products that require comparatively less protein of a weaker strength than hard wheat flour. This has resulted in the belief that protein composition may not be important in soft wheat; thus, the HMW-GS composition of soft wheat and its association with end-use quality have received relatively little attention. Some U.S. soft wheat varieties, however, have been found to yield grain containing much stronger protein than others, making them suitable for use in products such as crackers and potentially suitable for noodles and steamed bread, which all require protein of a relatively higher quantity and strength. HMW-GS composition, together with the presence/absence of translocated rye genes, is known to account for 55-67% of the variation in the bread-making quality of wheat. Among the U.S. eastern soft winter (ESW) wheat varieties tested, we observed wide variations in HMW-GS and rye translocation profiles. The frequency of each HMW-GS, and its contribution to protein content and strength, were identified. Additionally, we detected for the first time the presence of two rare HMW-GSs, 2.. and 2+121, and found that subunit 2+121 has a relatively high frequency and is associated with weak protein strength. The ESW wheat genotypes possessing a HMW-GS composition of 1 or 2.. or 2* at the Glu-A1 locus, 13+16 or 7*+8 at the Glu-B1 locus, and 5+10 at the Glu-D1 locus, without the 1BL/1RS rye translocation, are expected to produce wheat grain containing strong gluten proteins. The information on the HMW-GS composition of ESW wheat varieties, the contribution of each HMW-GS to protein characteristics, and the relationship between HMW-GS profiles and protein strength are expected to be valuable for screening and developing wheat varieties possessing the appropriate protein characteristics required for each type of soft wheat product.

Technical Abstract: Knowledge of HMW-GS composition and rye translocations of U.S. eastern soft winter (ESW) wheat, and their associations with protein characteristics will be helpful for the identification and selection of genotypes possessing the appropriate gluten strength for wheat-based products. HMW-GS composition and rye translocations of 149 ESW wheat varieties and their relationships with lactic acid solvent retention capacity and SDSS volume were determined. Subunits 2*, 7+8 and 2+12 are the predominant HMW-GSs in ESW wheat with frequencies of 72.7%, 47.7% and 36.7%, respectively. Two rare subunits, 2.. at Glu-A1 locus and 2+121 at Glu-D1 locus, were detected for the first time in ESW wheat, with frequencies of 1.6% and 21.9%, respectively. 1BL/1RS and 1AL/1RS translocations were observed in 18.8% and 10.9% of ESW wheat, respectively. Subunits 13+16, 5+10, and the absence of 1BL/1RS translocation showed associations with strong protein strength, whereas subunits 2+121 were associated with weak protein strength. Four HMW-GS profiles (2*, 7+8, 2+121), (2*, 7+8, 5+10), (2*, 7+9, 2+12), and (2*, 7+8, 2+12) were predominantly observed in 50.1% of ESW wheat. ESW wheat genotypes carrying subunits 13+16 or 7*+8 at Glu-B1 locus and 5+10 at Glu-D1 locus without 1BL/1RS translocation are expected to produce wheat grain containing strong-gluten proteins.