DIVERSITY OF FUNGAL SYMBIONTS IN ARBUSCULAR MYCORRHIZAS FROM A NATURAL COMMUNITY

The arbuscular mycorrhizal (AM) association between fungi in the order Glomales and the roots of a very wide range of vascular plants is of global ecological significance but has proved particularly intractable to study in the field. We have developed a reliable technique to iden tify the fungal symbionts in roots taken directly from natural communi ties. Selective Enrichment of Amplified DNA combines the use of recent ly-developed specific DNA primers with a novel method based on the pri nciple of subtractive hybridization to remove interfering plant-derive d DNA after amplification with the polymerase chain reaction. Using th is technique we have shown that endomycorrhizas of bluebells (Hyacinrh oides non-scripta) sampled directly from a woodland habitat are multis pecies communities of varying composition which contain at least three genera of mycorrhizal fungi. The technique works well on a range of p lant species and should have wide application to the identification of other symbionts, including pathogens. A spore survey has indicated th at two particular AM types are associated with bluebells and this obse rvation corroborates the molecular data. The presence of a Glomus spec ies in bluebell roots was not expected from the spore data.