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United States Department of Agriculture

Agricultural Research Service

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Location: Cereal Crops Research

2011 Annual Report

1a. Objectives (from AD-416)
To map genes for Fusarium head blight (FHB) resistance and low mycotoxin contamination, and for pests such as Russian wheat aphid; Develop improved green plant regeneration techniques from barley tissue cultures for genotype-independent genetic engineering of disease and pest resistance; Develop transgenic barley lines expressing combinations of pathogen response and anti-DON genes, test gene expression, and evaluate for effects on Fusarium graminearum and other fungal pathogens.

1b. Approach (from AD-416)
Single quantitative trait locus (QTL) lines for loci involved in FHB and mycotoxin resistance from Zhedar 2 will be developed by backcrossing, fine-mapped using all available molecular markers, and characterized in replicated field trials. Candidate genes from collaborative projects will be verified by inserting the genes into susceptible cultivars via transformation, and testing homozygous progeny in the field. RWA resistance genes in ARS germplasm releases will be mapped using a variety of molecular markers. The involvement of ethylene in tissue culture regeneration will be tested by manipulating ethylene levels with inhibitors and precursors. Optimal timing for ethylene exposure will be determined and tested using commercial barley cultivars. Genes responsible for ethylene perception, synthesis and regulation will be isolated and characterized by following their expression through the tissue culture process. Antifungal and antitoxin genes will be inserted into a commercial barley cultivar using particle bombardment. Resulting lines will be tested in the lab for gene expression using northern and western analyses, and in the field for reaction FHB and other diseases.

3. Progress Report
Barley lines carrying genes with potential antifungal effects were tested for Fusarium head blight (FHB) reaction and contamination by the mycotoxin deoxynivalenol (DON) in field trials. Two transgenic lines showed approximately 40% less DON than control plants in 4 years of field testing. These lines are being crossed to FHB resistant lines developed by barley breeders in ND and MN to see if the effects are additive. Ethylene is a plant hormone involved in response to disease and in regeneration from tissue cultures. The chromosomal location of 21 members of the gene families responsible for ethylene biosynthesis and reception were determined. Unique primers were designed for each member of the gene families for future gene expression studies.

4. Accomplishments

Review Publications
Naeem, R., Dahleen, L.S., Mirza, B. 2011. Genetic differentiation and geographical relationship of Asian barley landraces using SSRs. Genetics and Molecular Biology. 34:268-273.

Tyagi, N., Dahleen, L.S. 2011. Timing of Ethylene Modification Is Critical For Regeneration In Barley. Plant and Molecular Biology and Biotechnology. 4:47-55.

Thomas, W., Hayes, P., Dahleen, L.S. 2011. Barley: Production, Improvement, and Uses. Application of Molecular Genetics and Transformation to Barley Improvement. Book Chapter. 122-143.

Last Modified: 10/19/2017
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