Location: Cereal Disease Lab
Project Number: 3640-21220-020-00-D
Project Type: In-House Appropriated
Start Date: Apr 11, 2007
End Date: Apr 10, 2012
New funds will be used to expand the current research objectives for this ARS project to prepare for the possible appearance of Ug99 in North America. Those objectives are: Objective 1: Monitor and characterize races of cereal rust pathogens, particularly the new East African strain, Ug99. This includes the sub-objective of characterizing races of cereal stem rust, particularly Ug99 and related mutants, which represent a threat to the production of wheat, oat, and barley cultivars in the United States. Objective 2: Identify features essential for cereal rust pathogensis including sub-objectives of characterizing the genome of Puccinia graminis (stem rust). Research for this objective will be expanded to characterize the Ug99 genome sequence and to develop detection methods for the new Eastern African stem rust mutants. Objective 3: Identify resistance genes and develop effective strategies for deploying host-resistance genes to control cereal rust diseases. Research for this objective will be expanded to identify new sources of Ug99 resistance and to accelerate the development of Ug99-resistant wheat and barley varieties adapted for U.S. production.
Cereal rust pathogens continuously evolve to overcome existing host resistance genes in wheat, barley, and oats. Cereal germplasm with durable rust resistance, and other control strategies are needed to minimize yield losses due to cereal rusts. Variation in cereal rust populations will be analyzed by assessing virulence polymorphism to important rust resistance genes and by using molecular polymorphism to determine the relatedness and relationships between these populations. Migration patterns of cereal rust populations will be established using virulence and molecular markers. Virulence shifts in cereal rust populations in major cereal-producing areas of the U.S. in relation to use of rust resistance genes will be analyzed. Cereal germplasm with rust resistance will be evaluated in seedling plant tests and in adult plant field tests. Advanced germplasm lines with combinations of rust resistance genes will be selected. Cereal germplasm with durable resistance will be genetically analyzed to determine the identity and expression of the rust resistance genes. A genetic map of P. graminis will be constructed using AFLPs, SSRs, and SNPs. Physical maps of regions with avirulence genes will be developed using BAC and cosmid libraries. Genetic determinants of early infection processes in cereal rusts will be characterized. Crosses will be made with other cereal rust fungi to determine the genetics of avirulence/virulence to important rust resistance genes.