Identification and Isolation Pattern of spp. from a Moss Colony in Ny-Ålesund, Spitsbergen Is., Norway from 2006 to 2018.

spp. are soil-inhabiting oomycetes distributed worldwide, including in polar regions. Some species of the genus are known as important plant pathogens. This study aimed to clarify the species construction of spp. and their long-term isolation pattern in moss in Ny-Ålesund, Spitsbergen Is., Norway. spp. were isolated at two-year intervals between 2006 and 2018 at a moss colony, Ny-Ålesund, Spitsbergen Is., Norway. The isolates were obtained by using three agar media and were identified based on sequences of the rDNA-ITS region and cultural characteristics. Most of the isolates obtained during the survey were identified into six species. All six species were grown at 0 °C on an agar plate and used to infect moss at 4 and/or 10 °C under an in vitro inoculation test. The total isolation frequency of gradually decreased throughout the survey period. The isolation frequency varied among the six species, and four of the species that showed a high frequency in 2006 were rarely isolated after 2016. The results suggested that inhabiting moss in Ny-Ålesund has a unique composition of species and that most of the species reduced their population over the recent decade.