Intrasporal variability of ribosomal sequences in the endomycorrhizal fungus Gigaspora margarita

The sequence variability of the ribosomal internal transcribed spacer (ITS) region, which comprises the 5.8 gene and the flanking regions ITS1 and ITS 2, was investigated in the arbuscular mycorrhizal fungus Gigaspora margarit a. DNA analysis of a multispore preparation and three single spores led to the identification of 11 slightly different sequences (three variants withi n a single spore), indicating substantial intersporal and intrasporal genet ic variability (up to 9% sequence divergence). The sequence variations insi de a single spore may be higher than that observed between spores. Even so, primers designed on the ITS1 and ITS2 regions identified Gi. margarita iso lates and detected the endophyte during colonization.