Saprolegniaceae identified on amphibian eggs throughout the Pacific Northwest, USA, by internal transcribed spacer sequences and phylogenetic analysis

Authors

Jill E. Petrisko, Idaho State University
Christopher A. Pearl, USGS Forest and Rangeland Ecosystem Science CenterFollow
David S. Pilliod, USDA Forest Service Rocky Mountain Research StationFollow
Peter P. Sheridan, Idaho State University
Charles F. Williams, Idaho State University
Charles R. Peterson, Idaho State UniversityFollow
R. Bruce Bury, USGS Forest and Rangeland Ecosystem Science Center

Date of this Version

11-8-2007

Comments

Published in Mycologia, 100(2), 2008, pp. 171–180.

Abstract

We assessed the diversity and phylogeny of Saprolegniaceae on amphibian eggs from the Pacific Northwest, with particular focus on Saprolegnia ferax, a species implicated in high egg mortality. We identified isolates from eggs of six amphibians with the internal transcribed spacer (ITS) and 5.8S gene regions and BLAST of the GenBank database. We identified 68 sequences as Saprolegniaceae and 43 sequences as true fungi from at least nine genera. Our phylogenetic analysis of the Saprolegniaceae included isolates within the genera Saprolegnia, Achlya and Leptolegnia. Our phylogeny grouped S. semihypogyna with Achlya rather than with the Saprolegnia reference sequences. We found only one isolate that grouped closely with S. ferax, and this came from a hatcheryraised salmon (Idaho) that we sampled opportunistically. We had representatives of 7–12 species and three genera of Saprolegniaceae on our amphibian eggs. Further work on the ecological roles of different species of Saprolegniaceae is needed to clarify their potential importance in amphibian egg mortality and potential links to population declines.