Six new species of Pythiogeton in Taiwan, with an account of the molecular phylogeny of this genus
Journal
Mycoscience
Journal Volume
54
Journal Issue
2
Pages
130-147
Date Issued
2013-03
Date
2013-03
Author(s)
Jin-Hsing Huang
Chi-Yu Chen
Yi-Sheng Lin
Pao-Jen Ann
Hung-Chang Huang
Wen-Hsin Chung
Abstract
Pythiogeton is a little-studied genus of pythialean Oomycete. The genus is characterized by producing its zoospores outside of the sporangium within an apparently naked protoplasmic mass, which formed from a discharge tube-vesicle complex. A total of nine morphologically distinct Pythiogeton species were identified, of which six were new species (Pythiogeton abundans, Pythiogeton microzoosporum, Pythiogeton oblongilobum, Pythiogeton paucisporum, Pythiogeton proliferatum, and Pythiogeton puliensis). A phylogenetic analysis based on internal transcribed spacer sequences revealed that all isolates of Pythiogeton formed a highly supported clade, nested within the wider clade of Pythium species. Each newly recognized Pythiogeton species that was established on the basis of morphological characters was found to occur in a well-supported subgroup within the Pythiogeton clade, confirming their assignment to new species. Pythiogeton shares a common ancestor with the monophyletic group of Pythium species that have predominantly filamentous sporangia rather than with the separate clade of Pythium species that have predominantly globose or ovoid sporangia. This study confirms that Pythium is an extremely heterogenous and polyphyletic genus containing a number of distinct clades of species, including Pythiogeton, which possess morphologically distinguishable characters. A synoptic key to all the described Pythiogeton species is provided.
Subjects
Morphology
Oomycetes
Pythium
Taxonomy
Publisher
Elsevier
Type
journal article