Elimination of omega-1,2 gliadins from bread wheat (Triticum aestivum) flour: effects on immunogenic potential and end-use quality

Authors: Altenbach, Susan; Chang, Han-Chang; YU, XUECHEN - Columbia University - New York; Seabourn, Bradford; GREEN, PETER - Columbia University - New York; ALAEDINI, ARMIN - Columbia University - New York

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2019
Publication Date: 5/19/2019
Citation: Altenbach, S.B., Chang, H., Yu, X.B., Seabourn, B.W., Green, P.H., Alaedini, A. 2019. Elimination of omega-1,2 gliadins from bread wheat (Triticum aestivum) flour: effects on immunogenic potential and end-use quality. Frontiers in Plant Science. 10:580. https://doi.org/10.3389/fpls.2019.00580.
DOI: https://doi.org/10.3389/fpls.2019.00580

Interpretive Summary: The gluten proteins are a complex group of proteins that are responsible for the commercial value of wheat flour. These proteins encompass about 70% of the total protein in wheat flour and are responsible for the unique viscoelastic properties that make it possible to produce a wide range of different food products. Some of the same proteins are also involved in human health conditions, including celiac disease, food allergies and other sensitivities. The current work describes a biotechnology approach that was used to eliminate one group of harmful gluten proteins from wheat flour, specifically the omega-1,2 gliadins. In the study, flour protein compositions from two of the resulting lines were analyzed in detail. The reactivity of flour proteins from the new lines with sera from patients with celiac disease was tested and showed reduced reactivity relative to the control. In addition, a number of tests that are routinely used to assess the performance of flour in producing wheat-based products were conducted. These tests demonstrated that the quality of wheat flour was improved by the removal of the omega-1,2 gliadins. The data suggest that biotechnology approaches may be used to create wheat lines with reduced immunogenic potential without compromising end-use quality.

Technical Abstract: The omega-1,2 gliadins are a group of wheat gluten proteins that contain immunodominant epitopes for celiac disease and also have been associated with food allergies. To reduce the levels of these proteins in the flour, bread wheat (Triticum aestivum cv. Butte 86) was genetically transformed with an RNA interference plasmid that targeted a 141 bp region at the 5’ end of an omega-1,2 gliadin gene. Flour proteins from two transgenic lines were analyzed in detail by quantitative two-dimensional gel electrophoresis and tandem mass spectrometry. In one line, the omega-1,2 gliadins were missing and there were few other changes in the proteome. In the other line, striking changes in the proteome were observed and nearly all gliadins and low molecular weight glutenin subunits were absent. High molecular weight glutenin subunits increased in this line and the HMW-GS that showed the largest increases had molecular weights slightly less than those in the non-transgenic, possibly due to post-translational processing. In addition, there were increases in non-gluten proteins such as triticins, purinins, globulins, serpins and alpha-amylase/protease inhibitors. Reactivity of flour proteins with serum IgG and IgA antibodies from a cohort of celiac disease patients was reduced significantly in both transgenic lines. Both mixing time and tolerance were improved in the line without omega-1,2 gliadins while mixing properties were diminished in the line missing most gluten proteins. The data suggest that biotechnology approaches may be used to create wheat lines with reduced immunogenic potential in the context of gluten sensitivity without compromising end-use quality.