Blast: a serious wheat disease
B. VALENT (1), M. Farman (2), K. Pedley (3), G. Peterson (3), C. Cruz (1), W. Bockus (1), R. Whitley (2), M. Navia-Urrutia (1), H. Trick (1), J. Nunes-Maciel (4), P. Paul (5), E. Oliveira-Garcia (1), J. Stack (1) (1) Kansas State University, U.S.A.; (2) University of Kentucky, U.S.A.; (3) USDA-ARS Foreign Disease-Weed Science Research Unit, U.S.A.; (4) EMBRAPA-Trigo, Brazil; (5) The Ohio State University, U.S.A.

The blast fungus Magnaporthe oryzae (synonym-Pyricularia oryzae) is differentiated into host-specialized populations including a wheat-adapted population (the Triticum pathotype, MoT) first reported in Brazil in 1985. Over the subsequent years, wheat blast disease has spread within South America and, this February, it occurred for the first time in Bangladesh. Wheat blast has proven difficult to control in disease-conducive environments because few wheat blast resistance genes have been identified and fungicides usually offer limited control under these conditions. A wild wheat chromosome segment, the 2NS/2AS translocation from Aegilops ventricosa that is already deployed for its rust resistance genes, confers wheat blast resistance in some genetic backgrounds (Cruz et al, 2016, Crop Science), but there is an urgent need to identify additional wheat blast resistance loci. Phylogenetic analyses based on whole genome sequencing have shown that the wheat-adapted fungal population is distinct from the one that infects rice, but it is closely related to a pathogen population causing gray leaf spot on US turf grasses (the Lolium pathotype, MoL). The genome sequence data has also informed the development of M. oryzae population-specific diagnostics. Wheat blast strains contain functional alleles of known rice blast avirulence genes, which suggests that the corresponding cloned rice resistance genes might be useful for controlling blast disease in wheat.


Abstract Number: S6-4
Session Type: Special Session