Document: CHR-3-58-23

Characterization of the ectomycorrhizal fungi associated with the alpine sedge (Kobresia myosuroides).

SCHADT, C.W.* and S.K.SCHMIDT

University of Colorado, Boulder, Colorado 80303 USA ¹

Abstract:
Kobresia myosuroides is an alpine and arctic member of the Cyperaceae and is the only known member of this family to form ectomycorrhizal (ECM) associations. Three dominant species of fungi have been observed to form ECM relationships with this plant at the Niwot Ridge LTER site in Colorado. Each of these types has been observed repeatedly over the last three growing seasons. The identity of these fungi has been investigated using phylogenetic analysis of DNA sequences of the small subunit (SSU) and the internal transcribed spacer (ITS) region of ribosomal DNA. All three of the dominant types associated with this plant have been cultured and sequenced and appear to be within the Euascomycetes. The most abundant of these fungi fits the traditional morphological and previous molecular characterizations of Cenococcum geophilum. The second most abundant type falls within a Euascomycete clade containing Leotiales and Erisyphales with strong bootstrap support. The phylogenetic position of the third most abundant type is very close to the that of the second and the two are only significantly divergent within the ITS gene region. Each of these fungi form an ectomycorrhizal morphology with K. myosuroides similar to that of other woody angiosperms, including a mantle and Hartig net structure. These results, as well as recently published data on the ability of such fungi as Hymenosypus ericae, and Geopixus carbonaria, to form ectomycorrhizal associations, suggest that the mycorrhizal status of members of the Euascomycetes needs further attention, in addition to an up to date review.

Keywords: mycorrhizae, fungi, ascomycetes

This abstract is being presented at: 3:30 PM in session:
MYCORRHIZAL FUNGI