Location: Crop Improvement and Genetics Research
Project Number: 2030-21430-013-00-D
Project Type: Appropriated
Start Date: May 20, 2013
End Date: May 19, 2018
1) Identify the cysteine residues in high-molecular weight glutenins that participate in intermolecular disulfide bonds in order to improve wheat dough strength and stability. 2) Develop more efficient methods for the production of intra- and transgenic wheat plants for improved bread-making quality.
Objective 1). Site-directed mutagenesis will be used to create variants of the High-Molecular-Weight-glutenins in transgenic wheat. The new HMW-glutenins will be designed either to lack individual cysteine amino acids or with changes in the spacing of their cysteines. The variant genes will be introduced into hexaploid wheat by biolistics. The effects of the cysteine modifications on gluten polymer formation in the transgenic seeds will be assessed biochemically and with small-scale mixing tests. In a second line of research, transgenic wheat containing high levels of HMW-glutenin Dx5 or Dy10 in their seeds will be crossed to one another to obtain lines in which the amounts of x- and y-type subunits are approximately equal. The mixing properties of the flours derived from those hybrid lines will be assessed by small-scale mixing tests. Objective 2). Experiments designed to improve the efficiency of recovering wheat transformants made by biolistics will use a gene encoding the DsRed fluorescent protein. This gene will be bombarded into wheat embryos and the fate of the DNA during the regeneration steps will be visualized by following the fate of the fluorescent marker. The effect of differing amounts and physical states (single-stranded vs. double-stranded, circular vs linear) of the bombarded DNA on integration efficiencies will be assessed. The efficiencies of different selection schemes for identifying transformants will be measured. The effectiveness of the Ds transposable element for generating multiple useful transgenic plants from a single wheat transformation event will be tested. Genetically engineered wheat plants with increased dough strength due to the presence of high levels of HMW-glutenin Dy10 will be generated from this work.