Comparison of ribosomal DNA ITS regions among geographic isolates of Cenococcum geophilum.

Published

Journal Article

Cenococcum geophilum is an ecologically important mycorrhizal fungus with a global distribution and a wide host range. It has been difficult to study since it forms only sterile mycelia and, occasionally, sclerotial bodies. Because of its lack of morphological variability, its taxonomy and phylogenetic origins have until recently remained unclear. To better understand the genetic variation and environmental adaptability of C. geophilum, a molecular phylogeny was constructed based on the nuclear ribosomal DNA internal transcribed spacers (ITS1 and ITS2) of 69 isolates from various hosts and habitats. The results suggest DNA sequence conservation in the ITS regions. Considering its broad geographic and host range, this ITS conservation was unexpected. Our data imply that the ITS2 region is under evolutionary pressure to maintain the RNA secondary structure (similar to the pressure on the CgSSU introns) involved in the post-transcriptional processing of rRNA. Also, C. geophilum has very short ITS regions, thus limiting the number of mutable sites. This limited ITS variability suggests a recent radiation of C. geophilum, having been geographically distributed by a variety of efficient processes. C. geophilum appears to be a single taxonomic entity, possibly a single species. Therefore, it is an extremely adaptable, as well as ecologically valuable, taxon.

Full Text

Duke Authors

Cited Authors

  • Shinohara, ML; LoBuglio, KF; Rogers, SO

Published Date

  • June 1999

Published In

Volume / Issue

  • 35 / 5

Start / End Page

  • 527 - 535

PubMed ID

  • 10369960

Pubmed Central ID

  • 10369960

International Standard Serial Number (ISSN)

  • 0172-8083

Digital Object Identifier (DOI)

  • 10.1007/s002940050449

Language

  • eng

Conference Location

  • United States