The wheat HMW-glutenin 1Dy10 gene promoter controls endosperm expression in Brachypodium distachyon

Authors: Thilmony, Roger; Guttman, Mara; Lin, Jeanie; Blechl, Ann

Submitted to: GM Crops
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2013
Publication Date: 1/1/2014
Publication URL: http://dx.doi.org/10.4161/gmcr.27371
Citation: Thilmony, R.L., Guttman, M.E., Lin, J.W., Blechl, A.E. 2014. The wheat HMW-glutenin 1Dy10 gene promoter controls endosperm expression in Brachypodium distachyon. GM Crops. 5:36-43.

Interpretive Summary: Wheat is an important crop, providing a dietary staple for much of the world’s population. Biotechnology can help address obstacles to wheat cultivation, such as disease and suboptimum growing conditions, as well as enhance traits of interest, such as grain nutrient fortification. Important components of biotechnology are the promoters (or genetic switches) that determine when in development and where in the plant genes are turned on or off. A promoter from wheat called 1Dy10 has been isolated and shown to activate gene expression in the endosperm of the seeds of genetically engineered wheat and Brachypodium distachyon plants. This molecular tool will facilitate the improvement of wheat and potentially other cereal crops by enabling biotechnologists to synthesize compounds in the storage tissue of seeds while excluding those compounds from other parts of the plant.

Technical Abstract: The grass species Brachypodium distachyon has emerged as a model system for the study of gene structure and function in temperate cereals. As a first demonstration of the utility of Brachypodium to study wheat gene promoter function, we transformed it with a T-DNA that included the GUS reporter gene under control of a wheat High-Molecular-Weight Glutenin Subunit (HMW-GS) gene promoter and transcription terminator. For comparison, the same expression cassette was introduced into wheat by biolistics. Histochemical staining for GUS activity showed that the wheat promoter was highly expressed in the endosperms of all the seeds of Brachypodium and wheat homozygous plants. It was not active in any other tissue of transgenic wheat, but showed variable and sporadic activity in a minority of styles of the pistils of four homozygous transgenic Brachypodium lines. The ease of obtaining transgenic Brachypodium plants and the overall faithfulness of expression of the wheat HMW-GS promoter in those plants make it likely that this model system can be used for studies of other promoters from cereal crop species that are difficult to transform.