IDENTIFICATION OF ARBUSCULAR MYCORRHIZAL FUNGI FROM ARTEMISIA-CALIFORNICA USING THE POLYMERASE CHAIN-REACTION

The obligately symbiotic group of fungi, the arbuscular mycorrhizal (A M) fungi possess several characteristics that make identification, and therefore ecological field studies, difficult. A major limitation is that this group cannot be grown in pure culture. Traditional methods o f identifying this group rely on the isolation of asexual spores from the soil. These spores, which are resting structures, do not necessari ly reflect what species is actively colonizing the plant root. We have recently utilized molecular methods to develop a protocol for identif ying AM fungi. Field collected spores were identified using traditiona l microscopy, and the DNA extracted for amplification. A DNA extractio n method using crude lysate was developed which eliminates the need fo r a large amount of tissue and produces a DNA template suitable for PC R amplification. Results indicate that size polymorphisms in the ITS r egion of rDNA can distinguish between genera, and can be used to scree n species. Amplification products of field collected Artemisia califor nica roots showed that these fungal endophytes may be identified to sp ecies based on size polymorphisms.