Toward reducing the immunogenic potential of wheat flour: Identification and characterization of wheat lines missing omega-5 gliadins encoded by the 1D chromosome

Authors: KIM, SEWON - National Institute For Agricultural Engineering - Korea; SIM, JAE-RYEONG - National Institute For Agricultural Engineering - Korea; Gu, Yong; ALTENBACH, SUSAN - Former ARS Employee; DENERY-PAPINI, SANDRA - Inrae; PINEAU, FLORENCE - Inrae; TRANQUET, OLIVIER - Inrae; YANG, YU-JEONG - National Institute For Agricultural Engineering - Korea; JI PARK, EUN - National Institute For Agricultural Science & Technology; LIM, SUN-HYUNG - Hankyong National University; KANG, CHON-SIK - Korean Rural Development Administration; CHOI, CHANGHYUN - National Institute Of Crop Science - Korea; LEE, JONG-YEOL - National Institute For Agricultural Engineering - Korea

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2022
Publication Date: 3/10/2023
Citation: Kim, S., Sim, J., Gu, Y.Q., Altenbach, S.B., Denery-Papini, S., Pineau, F., Tranquet, O., Yang, Y., Ji Park, E., Lim, S., Kang, C., Choi, C., Lee, J. 2023. Toward reducing the immunogenic potential of wheat flour: Identification and characterization of wheat lines missing omega-5 gliadins encoded by the 1D chromosome. Theoretical and Applied Genetics. 136. Article 33. https://doi.org/10.1007/s00122-023-04295-0.
DOI: https://doi.org/10.1007/s00122-023-04295-0

Interpretive Summary: Gluten proteins are the major components of wheat flour and important determinants of wheat end-use quality, but also present significant health problems for consumers with wheat related disease such as wheat allergies, celiac disease, and non-celiac wheat sensitivities. Among these gluten proteins, omega-5 gliadins are known to cause wheat-dependent exercise-induced anaphylaxis (WDEIA), a severe form of food allergy. In this work, we screened 665 wheat germplasm samples to identify lines missing genes encoding omega-5 gliadins. A total of eleven lines were identified using polymerase chain reaction methods and specific primers targeted to the omega-5 gliadins encoded by the wheat 1D chromosome. These 11 wheat lines were further characterized by gene copy number analysis, 2-dimensional protein gel and immunoreactive assay using human sera from WDEIA patients. The genetic resources generated are useful source of breeding materials to breed hypoallergenic wheat varieties in the future.

Technical Abstract: Efforts to reduce the levels of allergens in wheat flour that cause wheat-dependent exercise-induced anaphylaxis are complicated by the presence of genes encoding omega-5 gliadins on both chromosomes 1B and 1D of hexaploid wheat. In this study, we screened 665 wheat germplasm samples using gene specific DNA markers for omega-5 gliadins encoded by the 1D chromosome that were obtained from the reference wheat Chinese Spring. Eleven wheat lines missing the PCR product corresponding to 1D omega-5 gliadin gene sequences were identified. Two of the lines contained the 1BL.1RS translocation. Relative quantification of gene copy numbers by qPCR revealed that copy numbers of 1D omega-5 gliadins in the other nine lines were comparable to those in 1D null lines of Chinese Spring, while copy numbers of 1B omega-5 gliadins were like those of Chinese Spring. 2-D immunoblot analysis of total flour proteins from the selected lines using a specific monoclonal antibody against the N-terminal sequence of omega-5 gliadin showed no reactivity in regions of the blots containing previously identified 1D omega-5 gliadins. Interestingly, RP-UPLC analysis of the gliadin fractions of the selected lines indicated that the expression of omega-1,2 gliadins was also significantly reduced in five of the lines, implying that 1D omega-5 gliadin and 1D omega-1,2 gliadin genes are tightly linked on the Gli-D1 loci of chromosome 1D. Wheat lines missing the omega-5 gliadins encoded by the 1D chromosome should be useful in future breeding efforts to reduce the immunogenic potential of wheat flour.