Compatible and Incompatible Interactions Exist between the Model Grass Species Brachypodium distachyon and the Cereal Pathogen Cochliobolus sativus

Recently, Brachypodium distachyon has emerged as a new model system for studying temperate cereal crops and grass species due to its small genome size, short life cycle and many other features. However, it is immune or highly resistant to most of the cereal and grass pathogens tested. To investigate the host-pathogen interaction between B. distachyon and Cochliobolus sativus, an important fungal pathogen that causes common root rot, spot blotch and kernel blight in barley and wheat, five B. distachyon lines (Bd1-1, Bd21, Bd2-3, Bd3-1 and Bd18-1) were inoculated with five C. sativus strains (ND93-1, ND90Pr, ND85F, ND4008 and Cs07-47-1) that exhibited differential virulence on barley and wheat differential lines. The results indicated that all tested C. sativus strains infected the five B. distachyon lines although their virulence varied depending on the B. distachyon lines used. Further evaluation of 192 B. distachyon accessions of diverse background with two of the fungal strains (ND4008 and Cs07-47-1) revealed a broad range of responses from a hypersensitive response (HR)-mediated resistance to full susceptibility in the host. Studies on genetics of the resistance in B. distachyon to C. sativus are in progress and will be presented. The availability of whole genome sequences of both host and pathogen makes the B. distachyon-C. sativus pathosystem an attractive new model for studying host-pathogen interactions in cereal crops.