Distribution of ericoid mycorrhizal endophytes and root-associated fungi in neighbouring Ericaceae plants in the field

Three hundred and twenty-seven fungal endophyte isolates were obtained from hair roots of neighbouring Woollsia pungens Cav. (Muell.) and Leucopogon parviflorus (Andr.) Lindl. (both Ericaceae) plants at an Australian dry sclerophyll forest site and mapped according to the root segments from which they were obtained. Restriction fragment length polymorphism (RFLP) analysis of the rDNA internal transcribed spacer (ITS) region indicated that the isolate assemblage comprised 21 RFLP-types (= putative taxa), five of which were shown in gnotobiotic culture experiments to be ericoid mycorrhizal endophytes. While two mycorrhizal RFLP-types were exclusive to either W. pungens or L. parviflorus, RFLP-type VI was isolated from both hosts. This putative taxon had strong ITS sequence identity with Helotiales ericoid mycorrhizal ascomycetes, comprised ca. 75% of all isolates from each plant and was spatially widespread in both root systems. Inter-simple sequence repeat PCR analysis indicated that two and four genotypes of RFLP-type VI were present in the W. pungens and L. parviflorus root systems respectively, however single genotypes appeared to dominate each root system. One genotype was present in both root systems. The data suggest that assemblages of ericoid mycorrhizal fungi from hair roots of individual Ericaceae plants in dry sclerophyll forest habitats are characterised by relatively low genetic diversity.