Submitted to: Journal of Cereal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/6/2005
Publication Date: 9/1/2005
Citation: He, G.H., Jone, H.D., D'Ovidio, R., Masci, S., Chen, M., West, J., Butow, B., Anderson, O.D., Lasseri, P., Fido, R., Shewry, P. 2005. Expression of an extended hmw subunit in transgenic wheat and the effect on dough mixing properties. Journal of Cereal Science. 42: 225-231. Interpretive Summary: The high-molecular-weight glutenin subunits are critical components of wheat, particularly the ability of doughs to form the appropriate visco-elastic properties required for breadmaking. How these subunits contribute to dough characteristics is not understood at the molecular level. These experiments address this lack of knowledge by studying the effects of changing the glutenin subunit structure - in this case the central region of the polypeptide where it is composed of a series of repeating peptide motifs. A modified glutenin with a longer repeat structure was synthesized in transgenic wheat plants using a gene with an extended region encoding the repeat region. The paper reports on this extended gene, its expressed protein, and initial resuslts on dough properties.
Technical Abstract: Wheat line L88-31 was tranformed with a gene encoding an extended form of subunit 1Dx5 to study the relationship between subunit size and the effect on dough mixing properties. Four transgenic lines were recovered, one of which expressed a truncated form of the protein with mobility between those of the wild type and extended subunits. Comparison of the Mixograph profiles and gluten protein compositions with those of the control lines and a line expressing the wild type subunit 1Dx5 transgene showed that two of the transgenic lines had poor mixing properties and that this was associated with co-suppression of HMW subunit gene expression. The other two transgenic lines had improved mixing properties (measured as increased mixing time) and this was associated with increased proportions of large glutenin polymers. None of the transgenic lines expressing the extended form of the 1Dx5 subunit showed the 'overstrong' mixing propterties exhibited by trangenic lines expressing the wild type 1Dx5 transgene.