, a new species causing wheat blast.

is a species complex that causes blast disease on more than 50 species of poaceous plants. has a worldwide distribution as a rice pathogen and in the last 30 years emerged as an important wheat pathogen in southern Brazil. We conducted phylogenetic analyses using 10 housekeeping loci for 128 isolates of sampled from sympatric populations of wheat, rice, and grasses growing in or near wheat fields. Phylogenetic analyses grouped the isolates into three major clades. Clade 1 comprised isolates associated only with rice and corresponds to the previously described rice blast pathogen pathotype (PoO). Clade 2 comprised isolates associated almost exclusively with wheat and corresponds to the previously described wheat blast pathogen pathotype (PoT). Clade 3 contained isolates obtained from wheat as well as other hosts. We found that Clade 3 is distinct from and represents a new species, (Pgt). No morphological differences were observed among these species, but a distinctive pathogenicity spectrum was observed. Pgt and PoT were pathogenic and highly aggressive on (wheat), (barley), (signal grass), and (oats). PoO was highly virulent on the original rice host (), and also on wheat, barley, and oats, but not on signal grass. We conclude that blast disease on wheat and its associated hosts in Brazil is caused by multiple species. was recently found causing wheat blast in Bangladesh. This indicates that represents a serious threat to wheat cultivation globally.