The destructive tree pathogen phytophthora ramorum originates from the laurosilva forests of east asia

Thomas Jung*, Marília Horta Jung, Joan F. Webber, Koji Kageyama, Ayaka Hieno, Hayato Masuya, Seiji Uematsu, Ana Pérez-Sierra, Anna R. Harris, Jack Forster, Helen Rees, Bruno Scanu, Sneha Patra, Tomáš Kudláček, Josef Janoušek, Tamara Corcobado, Ivan Milenković, Zoltán Nagy, Ildikó Csorba, József BakonyiClive M. Brasier

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)
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As global plant trade expands, tree disease epidemics caused by pathogen introductions are increasing. Since ca 2000, the introduced oomycete Phytophthora ramorum has caused devastating epidemics in Europe and North America, spreading as four ancient clonal lineages, each of a single mating type, suggesting different geographical origins. We surveyed laurosilva forests for P. ramorum around Fansipan mountain on the Vietnam-China border and on Shikoku and Kyushu islands, southwest Japan. The surveys yielded 71 P. ramorum isolates which we assigned to eight new lineages, IC1 to IC5 from Vietnam and NP1 to NP3 from Japan, based on differences in colony characteristics, gene x environment responses and multigene phylogeny. Molecular phylogenetic trees and networks revealed the eight Asian lineages were dispersed across the topology of the introduced European and North American lineages. The deepest node within P. ramorum, the divergence of lineages NP1 and NP2, was estimated at 0.5 to 1.6 Myr. The Asian lineages were each of a single mating type, and at some locations, lineages of “opposite” mating type were present, suggesting opportunities for inter-lineage recombination. Based on the high level of phenotypic and phylogenetic diversity in the sample populations, the coalescence results and the absence of overt host symptoms, we conclude that P. ramorum comprises many anciently divergent lineages native to the laurosilva forests between eastern Indochina and Japan.

Original languageEnglish
Article number226
JournalJournal of Fungi
Issue number3
Publication statusPrint publication - 18 Mar 2021
Externally publishedYes


  • Biosecurity
  • Epidemic
  • Evolutionary history
  • Lineages
  • Mating types
  • Phylogeny


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