Pythium polare, a new heterothallic oomycete causing brown discolouration of Sanionia uncinata in the Arctic and Antarctic

Motoaki Tojo*, Pieter Van West, Tamotsu Hoshino, Kenichi Kida, Hirokazu Fujii, Akiho Hakoda, Yuki Kawaguchi, Hermann A. Mühlhauser, Albert H. Van Den Berg, Frithjof C. Küpper, María L. Herrero, Sonja S. Klemsdal, Anne Marte Tronsmo, Hiroshi Kanda

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Pythium polare sp. nov. is a new heterothallic oomycete species isolated from fresh water and moss from various locations in both the Arctic and Antarctic. This water mould is able to infect stems and leaves of Sanionia moss (Sanionia uncinata). Pythium polare causes brown discolouration in in vitro inoculation tests at 5 °C after 5 weeks of inoculation. It is characterized by globose sporangia with various lengths of discharge tubes releasing zoospores and aplerotic oospores with usually one to five antheridia. The sexual structures are only produced in a dual culture of antheridial and oogonial isolates. Phylogenetic analysis, based on ITS sequencing, places all isolated strains of P. polare in a unique new clade, hence it is considered a novel species. Pythium canariense and Pythium violae are the most closely related species of P. polare based both on morphology and the phylogenetic analysis.

Original languageEnglish
Pages (from-to)756-768
Number of pages13
JournalFungal Biology
Issue number7
Early online date27 Apr 2012
Publication statusPublished - Jul 2012

Bibliographical note

This study was supported from the Japan Society for the Promotion of Science by the grant-in-aid for scientific research Nos. 19510033, 23510032, and 23247012 (MT) the Natural Environment Research Council (NERC) via the SOFI initiative (award NE/F012705/1) (PvW), the University of Aberdeen (HvdB) and the Total Foundation (PvW, FCK).


  • Bipolar distribution
  • Moss
  • Oomycete
  • Plant pathogen
  • Pythium polare
  • Sanionia uncinata


Dive into the research topics of 'Pythium polare, a new heterothallic oomycete causing brown discolouration of Sanionia uncinata in the Arctic and Antarctic'. Together they form a unique fingerprint.

Cite this