ICOM1 Abstract

BUCKNER, B., S.K. HARNEY, S.K., F.S. EDWARDS AND M.F. ALLEN. San Diego State University, Biology Department, San Diego, CA, 92182. -Preliminary identification of selected species of arbuscular mycorrhizal fungi using PCR amplified rDNA. The obligately symbiotic group of fungi, the arbuscular mycorrhizal (AM) fungi, possess several characteristics (e.g. inability to be grown in pure culture) which make identification, and therefore ecological field studies, difficult. Traditional methods of identifying this group rely on the isolation of asexual spores from the soil. These spores, which are resting structures, do not necessarily reflect what species are actively colonizing the plant root. We have recently utilized molecular methods to develop a protocol for identifying AM fungi. Field collected spores were identified using traditional microscopy, and DNA was extracted for amplification. DNA was extracted using crude lysate, which eliminates the need for a large amount of tissue, and produces a DNA template suitable for PCR amplification. Results indicate that size polymorphisms in the ITS region of rDNA can distinguish among genera, and can be used to screen species. Amplification products of field collected plant roots showed that these fungal endophytes may be identified to species based on size polymorphisms.