IMC7 Abstracts

118 - Molecular ecology of anaerobic fungi (Anaerobic fungi-do we know them all?)

¹Institute of Biological Sciences, University of Wales Aberystwyth, Penglais, Aberystwyth, Ceredigion SY23 3DA, Wales, U.K. - ²KSU, Agriculture Faculty, 46100 Kahramanmaras, Turkey. - ³Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion SY23 3EB, Wales, U.K. - E-mail: gwg@aber.ac.uk

Anaerobic fungi are important components of the rumen ecosystem but their physiology and enzymology have attracted more interest than their ecology. As such, information relating to the mechanisms and dynamics of spread between hosts and niche differentiation between species remain unanswered. It is not clear how many species may coexist in a single host animal, nor whether the various species differ in their patterns of substrate colonisation. We have conducted detailed analysis of fungal populations from rumen digesta and faeces of silage-fed cows, and have investigated the effect of environmental conditions on survival of these fungi in faeces. Using the MPN technique with various substrates as an enrichment source, quite different fungal taxa were isolated. For instance, Caecomyces spp. were more abundant on cellobiose. In the course of this work we also isolated and characterised a new genus of anaerobic fungus Cyllamyces (type species C. aberensis). Difficulties in reliable morphological identification led us to use PCR-RFLP of the ITS region of the rRNA locus as a tool for identifying fungi isolated from MPN tubes. Sequence analysis of these regions was used to validate restriction enzyme patterns. Ambiguous RFLP patterns were found to be attributable to between-repeat polymorphisms within the ITS region of single isolates. ITS2 sequences from a single isolate diverged by 5% or more and there was more variability between repeats than between quite unrelated isolates.