MYCDIRE, a dispersed repetitive DNA element in arbuscular mycorrhizal fungi

An EcoRI 1428 bp A + T-rich, DNA element (MYCDIRE: MYCorrhizal fungus Dispersed Repetitive Element) has been identified in the genome of Scutellospora castanea, an arbuscular mycorrhizal fungus. After sequencing, primers were designed and used in PCR reactions to amplify portions of this element in five species of arbuscular mycorrhizal fungi belonging to four genera of Glomales. Southern hybridizations and partial analysis of the main PCR products confirmed that this element was highly conserved in all the species. Southern blot analysis of single and double digested DNA from two of the glomalean fungi gave smears suggesting that MYCDIRE is scattered throughout the fungal genome. Sequence analyses revealed three copies of a previously reported autonomously replicating sequence (ARS) from Saccharomyces cerevisiae and comparisons indicated similarities of MYCDIRE with the autonomously replicating, A + T-rich element (ACARS) from Acremonium chrysogenum.