title: Pythium rishiriense sp. nov. from water and P. alternatum sp. nov. from soil, two new species from Japan.
abstract: In an investigation of Pythium species in natural ecosystems of Rishiri Island in Northern Japan, two new species, Pythium rishiriense and P. alternatum, were identified based on morphological and molecular analyses. Pythium rishiriense differed morphologically from other Pythium species by its characteristic oogonial formation which occasionally arranged in chains. Pythium alternatum differed morphologically from other Pythium species by its distinguishing sexual organs where oogonia occasionally arranged alternately with antheridia in chains. Pythium rishiriense is a fast growing, high-temperature loving species, while P. alternatum is a slow growing species. Phylogenetic analyses based on the internal transcribed spacer region and cytochrome c oxidase 1 gene sequences showed that these two species are clearly separate from morphologically similar species.
authors.affiliation: River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan rahman@green.gifu-u.ac.jp ziaur789@yahoo.com.
authors.forename: Mohammad Ziaur
authors.initials: MZ
authors.lastname: Rahman
authors.affiliation: Department of Biology, College of Science, Aljouf University, Sakaka 42421, Saudi Arabia.
authors.forename: Hani Mohamed Awad
authors.initials: HM
authors.lastname: Abdelzaher
authors.affiliation: River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Li
authors.initials: L
authors.lastname: Mingzhu
authors.affiliation: Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Motohashi
authors.affiliation: Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Suga
authors.affiliation: River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kageyama
mesh_terms: D001483:Base Sequence; D004275:DNA, Ribosomal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D006358:Hot Temperature; D007564:Japan; D010802:Phylogeny; D011775:Pythium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012987:Soil / Q000469:parasitology*; D014867:Water / Q000469:parasitology*
chemical_list: D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D012987:Soil; D014867:Water
keywords: high-temperature loving; identification; molecular phylogeny; morphology