Tracing the Origin and Evolutionary History of<i>Pyricularia oryzae</i>Infecting Maize and Barnyard Grass

Blast disease is a notorious fungal leading to dramatic yield losses on major food crops such as rice and wheat. The causal agent, Pyricularia oryzae, encompasses different lineages, each having host range. Host shifts are suspected have occurred in this species from Setaria spp. Lolium emergence of blast maize Iran was observed for the first time north country 2012. We later identified two additional regions Iran: Gilan 2013 Golestan 2016. Epidemics weed barnyard grass (Echinochloa spp.) were also same fields. Here, we showed that P. oryzae agent both hosts. Pathogenicity assays greenhouse revealed strains can infect conversely. However, genotyping with simple sequence repeat markers comparative genomics causing field epidemics different, although they belong previously undescribed clade oryzae. Phylogenetic analyses including these strain collected Gabon 1985 independent host-range expansion events maize. Comparative between presence or absence five candidate genes associated specificity maize, deletion small genomic region possibly responsible adaptation This recent provides case study understand range expansion. raise concerns about potential crop geographic disease.