Saville Amanda C, Martin Michael D, Ristaino Jean B
Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America.
Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
PLoS One. 2016 Dec 28;11(12):e0168381. doi: 10.1371/journal.pone.0168381. eCollection 2016.
Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, was responsible for the Irish potato famine of the 1840s. Initial disease outbreaks occurred in the US in 1843, two years prior to European outbreaks. We examined the evolutionary relationships and source of the 19th-century outbreaks using herbarium specimens of P. infestans from historic (1846-1970) and more recent isolates (1992-2014) of the pathogen. The same unique SSR multilocus genotype, named here as FAM-1, caused widespread outbreaks in both US and Europe. The FAM-1 lineage shared allelic diversity and grouped with the oldest specimens collected in Colombia and Central America. The FAM-1 lineage of P. infestans formed a genetic group that was distinct from more recent aggressive lineages found in the US. The US-1 lineage formed a second, mid-20th century group. Recent modern US lineages and the oldest Mexican lineages formed a genetic group with recent Mexican lineages, suggesting a Mexican origin of recent US lineages. A survey of mitochondrial haplotypes in a larger set of global herbarium specimens documented the more frequent occurrence of the HERB-1 (type Ia) mitochondrial haplotype in archival collections from 1866-75 and 1906-1915 and the rise of the Ib mitochondrial lineage (US-1) between 1946-1955. The FAM-1 SSR lineage survived for almost 100 years in the US, was geographically widespread, and was displaced first in the mid-20th century by the US-1 lineage and then by distinct new aggressive lineages that migrated from Mexico.
致病疫霉（Phytophthora infestans (Mont.) de Bary）是马铃薯晚疫病的病原体，它导致了19世纪40年代的爱尔兰马铃薯饥荒。最初的疫病爆发于1843年在美国出现，比欧洲爆发早两年。我们利用该病原体历史时期（1846 - 1970年）和近期分离株（1992 - 2014年）的致病疫霉标本，研究了19世纪疫病爆发的进化关系和源头。同一个独特的SSR多位点基因型，在此命名为FAM - 1，在美国和欧洲都引发了广泛的疫病爆发。FAM - 1谱系共享等位基因多样性，并与在哥伦比亚和中美洲收集的最古老标本归为一类。致病疫霉的FAM - 1谱系形成了一个遗传群体，与在美国发现的近期侵袭性谱系不同。US - 1谱系形成了第二个20世纪中叶的群体。近期的美国现代谱系和最古老的墨西哥谱系与近期的墨西哥谱系形成了一个遗传群体，这表明近期美国谱系起源于墨西哥。对大量全球标本馆标本中的线粒体单倍型进行的一项调查记录了HERB - 1（Ia型）线粒体单倍型在1866 - 1875年和1906 - 1915年的档案收藏中更频繁出现，以及Ib线粒体谱系（US - 1）在1946 - 1955年之间的兴起。FAM - 1 SSR谱系在美国存活了近100年，在地理上广泛分布，首先在20世纪中叶被US - 1谱系取代，然后被从墨西哥迁移而来的不同新侵袭性谱系取代。
