title: Persistence of the mitochondrial lineage responsible for the Irish potato famine in extant new world phytophthora infestans.
abstract: The plant pathogen Phytophthora infestans emerged in Europe in 1845, triggering the Irish potato famine and massive European potato crop losses that continued until effective fungicides were widely employed in the 20th century. Today the pathogen is ubiquitous, with more aggressive and virulent strains surfacing in recent decades. Recently, complete P. infestans mitogenome sequences from 19th-century herbarium specimens were shown to belong to a unique lineage (HERB-1) predicted to be rare or extinct in modern times. We report 44 additional P. infestans mitogenomes: four from 19th-century Europe, three from 1950s UK, and 37 from modern populations across the New World. We use phylogenetic analyses to identify the HERB-1 lineage in modern populations from both Mexico and South America, and to demonstrate distinct mitochondrial haplotypes were present in 19th-century Europe, with this lineage initially diversifying 75 years before the first reports of potato late blight.
authors.affiliation: Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark sameoldmike@gmail.com.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Martin
authors.affiliation: School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Simon Y W
authors.initials: SY
authors.lastname: Ho
authors.affiliation: Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Nathan
authors.initials: N
authors.lastname: Wales
authors.affiliation: Department of Plant Pathology, North Carolina State University.
authors.forename: Jean B
authors.initials: JB
authors.lastname: Ristaino
authors.affiliation: Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, DenmarkTrace and Environmental DNA laboratory, Department of Environment and Agriculture, Curtin University, Perth, Western Australia, Australia.
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
mesh_terms: D000569:Americas; D001499:Bayes Theorem; D004272:DNA, Mitochondrial / Q000032:analysis*; D019143:Evolution, Molecular; D049672:History, 19th Century; D007494:Ireland; D010802:Phylogeny; D058974:Phylogeography; D055750:Phytophthora infestans / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D010935:Plant Diseases / Q000266:history / Q000469:parasitology*; D011198:Solanum tuberosum / Q000469:parasitology*; D013217:Starvation / Q000266:history; D006113:United Kingdom
chemical_list: D004272:DNA, Mitochondrial
keywords: ancient DNA; evolutionary biology; mitogenomics; molecular evolution; pathogens; potato