Pandemic Wheat Blast Fungus Traced to Clonal Lineage

An international team reporting in PLOS Biology describes a clonal Magnaporthe oryzae ascomycete fungus lineage behind a wheat blast disease that has been introduced to Asia and Africa from South America at least twice. Using multiplex amplicon sequencing and published genome sequences, the researchers profiled 84 SNPs in more than 500 M. oryzae samples from a range of host sites and geographic locations, unearthing shared SNPs in more than a dozen wheat blast isolates from Zambia, dozens of Bangladesh samples, and a sample going back to 2012 from Bolivia, consistent with spread from South America. Their results also point to potential wheat blast control strategies, including fungicide sensitivity and the host resistance gene Rmg8. "Our results demonstrate that genomics can rapidly identify emerging pathogen genotypes to guide disease management and counteract emerging pathogen lineages," they write. "These findings will inform management strategies for this devastating wheat disease and warrant further genomic surveillance to prevent and manage future outbreaks."