IDENTIFICATION OF ENDOMYCORRHIZAL FUNGI COLONIZING ROOTS BY FLUORESCENT SINGLE-STRAND CONFORMATION POLYMORPHISM POLYMERASE CHAIN-REACTION

A method to identify arbuscular endomycorrhizal fungi based on the amp lification of portions of the nuclear gene coding for the small subuni t rRNA is presented. By coupling the sensitivity of the polymerase cha in reaction and the specificity afforded by taxon-specific primers, a variety of samples can be analyzed, including small amounts of coloniz ed roots. Family-specific primers as well as generic primers are descr ibed and can be used to amplify small subunit rRNA fragments from endo mycorrhizal fungi by polymerase chain reaction. The amplified products are then subjected to single-strand conformation polymorphism analysi s to detect sequence differences. Among the advantages of this approac h is the possibility of directly identifying the fungi inside field-co llected roots, without having to rely on the fortuitous presence of sp ores. This technique should have obvious applications in the study of arbuscular endomycorrhizal fungi populations and allow closer examinat ion of their host specificity.