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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Research Project #431808

Research Project: Cereal Rust: Pathogen Biology and Host Resistance

Location: Cereal Disease Lab

Project Number: 5062-21220-023-000-D
Project Type: In-House Appropriated

Start Date: Apr 11, 2017
End Date: Mar 27, 2022

Objective 1: Monitor, collect, and characterize U.S. cereal rust pathogens. Sub-objective 1.A. Monitor, collect, and characterize cereal rust pathogen populations in the U.S. for virulence to rust resistance genes in current cultivars. Sub-objective 1.B. Determine levels of genetic variation in Puccinia triticina, P. graminis and P. coronata populations. Sub-objective 1.C. Refine phylogenetics and systematics of P. graminis from Mahonia and other native Berberis spp. in North America. Objective 2: Further develop genomic resources of cereal rust pathogens and identify fungal genes involved in pathogenicity and development. Sub-objective 2.A. Identify effectors of P. graminis f. sp. tritici involved in fungal pathogenicity and host resistance. Sub-objective 2.B. Develop genomic resources and tools for more detailed analysis of P. coronata. Objective 3: Improve host resistance in cereal crops to rust pathogens through investigations in sources and genetics of rust resistance, characterization of various germplasm, and incorporation into adapted germplasm. Sub-objective 3.A. Evaluate wheat, oat and barley germplasm from U.S. breeding programs for rust resistance. Sub-objective 3.B. Identify and characterize new sources of rust resistance in wheat, barley, and oat; and incorporate into adapted germplasm.

Cereal rust fungi (Puccinia coronata, P. graminis, and P. triticina) are dynamic leading to constant changes in the U.S. population and erosion of effective rust resistance in cereal crops. In addition, introduction of foreign isolates, such as Ug99, further threaten cereal production. Development of cereal cultivars with effective rust resistance and management strategies of these diseases depend on monitoring, collection, virulence phenotyping, and genotypic characterization of cereal rust pathogen populations. Rust resistant cereal germplasm will be selected by testing wheat, oat, and barley lines from breeding programs throughout the U.S. and other sources for resistance to these pathogens using the prevalent races, and races that have high virulence to rust resistance genes common in released cultivars and breeding lines. Testing with selected isolates of the cereal rust pathogens and host genetics studies will identify the rust resistance genes in breeding lines and germplasm. Advanced germplasm lines with combinations of rust resistance genes will be selected and released for further use in cultivar development. Rust fungi produce a large arsenal of effector proteins in order to infect and colonize the plant host. Genetic and genomic approaches will be used to identify and characterize effector genes from P. graminis and P. coronata.