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Track emerging late blight in the US and South America using a disease alert and surveillance systems and population genomics

Jean Ristaino: NC State University

<div><em>Phytophthora infestans</em> caused historic disease in Ireland and is a threat to food security globally. We have tracked the recent and historic genotypes of <em>P. infestans</em> using multilocus genotyping, next generation sequencing, geospatial analytics and mapping. The same unique multilocus genotype, named FAM-1, caused both US and European historic outbreaks and was found in the oldest samples from Colombia. In 2009, potato and tomato late blight epidemics in the US were the worst in modern history due to widespread inoculum distribution from infected tomato transplants. A surveillance system called was deployed in the US to report disease outbreaks, pathogen genotypes and alerts growers of disease. Today the US-23 lineage is dominant in the US. Most recent lineages of <em>P. infestans</em> have emerged out of Mexico, however US-1 and US-23 share allelic diversity with South American (SA) lineages. Only a few clonal lineages of the pathogen have been found on <em>Solanum tuberosum</em> in the Andean countries, however the pathogen has been understudied there. The Latinblight network under development in SA will provide a shared database and will enable more studies of gene flow of the pathogen within the Americas and emergence of novel <em>Phytophthora</em> species. This will help clarify the phylogenetic origin of <em>Phytophthora </em>species associated with distinct plants within the Solanaceae family in South America, including the recently described species <em>P. betacei</em>. Furthermore it will allow tracking the migration routes and host range of these species.</div>

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