A multi-pronged approach to elucidate the molecular basis of rust virulence and non-host resistance in Brachypodium distachyon
M. FIGUEROA (1), F. Li (1), V. Omidvar (1), S. Rottschaefer (1), M. Miller (1), R. Milne (2), H. Karaoglu (3), D. Singh (3), M. Ayliffe (2), N. Upadhyaya (4), M. Moscou (5), R. Dill-Macky (1), E. Lagudah (2), P. Dodds (2), R. Park (3), S. Kianian (6) (1) University of Minnesota, U.S.A.; (2) CSIRO Agriculture, Australia; (3) Plant Breeding Institute, University of Sydney, Australia; (4) CSIRO Agriculture, U.S.A.; (5) The Sainsbury Laboratory, United Kingdom; (6) USDA-ARS Cereal Disease Laboratory, U.S.A.

The yield losses caused by rust fungi can be devastating to the production of small grains. Genomic variation within rust populations and the fast evolutionary capacity of these pathogens challenge the durability of host genetic resistance in the field. Stem rust in wheat and barley caused by Puccinia graminis f. sp. tritici (Pgt) and crown rust in oat caused by Puccinia coronata f. sp. avenae (Pca) represent two rust diseases that demand new resources to reduce the risk of outbreaks. Non-host resistance (NHR) offers the possibility to provide durable resistance in the commercial host. We have established a model system, utilizing Brachypodium distachyon, to study the basis of NHR against multiple cereal rust species, including Pgt and Pca. Because of the phylogenetic relatedness of B. distachyon to cereals, this species has potential applications to translational research. A functional genomics approach has been taken to determine the role of candidate genes in controlling NHR in B. distachyon against Pgt. In parallel, evaluation of the response of oat germplasm and wild relatives to a broadly virulent collection of Pca isolates is underway to detect novel sources of resistance. These studies are complemented with mutagenesis approaches to functionally validate effector predictions in Pgt and Pca and to examine the behavior of those effectors in a NHR system. Because the genomic tools to study Pca are rather limited, the construction of high quality genome assemblies of Pca isolates is underway.

Abstract Number: S4-2
Session Type: Special Session