Unusually compact ribosomal RNA gene cluster in Sphaeronaemella fimicola.

The ribosomal DNA repeat unit of Sphaeronaemella fimicola was found to be a 13.7-kb tandem repeat with a relatively long nontranscribed spacer (NTS) and an unusually compact ribosomal RNA gene cluster. The DNA sequence of an 850-bp PCR amplification product containing the 3' end of the small subunit rRNA (SSrRNA) gene, the 5.8s gene, and the 5' end of the large subunit rRNA (LSrRNA) gene was determined. The putative internal spacers flanking the 5.8s RNA gene could be the shortest yet noted for any fungus, totaling only 102 bases.