Yeast communities associated with ectomycorrhizal fungi in different Nothofagus forests of northwestern Patagonia

摘要

Many surveys have studied soil yeasts and ectomycorrhizal fungi independently and reported their association with water availability and soil nutrients. Nevertheless, the importance of yeasts associated with ectomycorrhizal fungi and different exploration types is little understood. The aim of the present study is to describe the diversity of yeasts inhabiting the ectomycorrhizosphere, and their association with the ectomycorrhizal fungal community, in four Nothofagus forests in northwestern Patagonia. Most ectomycorrhizal fungi sequences were assigned to eight ectomycorrhizal lineages, a high percentage of which were related to /cortinarius lineage. Less than 25 of these sequences were associated with /non-ectomycorrhizal lineages reported as endophytic fungi. A large proportion of the sequences (81) corresponded to the phylum Basidiomycota, and included the cosmopolitan genera Cortinarius, Inocybe and Tomentella. Three exploratory types were present in all forest sites, but with different distributions. The results showed that the ectomycorrhizal yeast communities were very diverse in the four forest sites studied. Ectomycorrhizospheric yeasts were also dominated by the phylum Basidiomycota, including the genera Naganishia, Solicoccozyma, Saitozyma and Piskurozyma. The species Apiotrichum porossum, Solicoccozyma podzolica, Solicoccozyma terricola, Solicoccozyma sp. and Humicolopsis cephalosporioides were frequently associated with EcM fungal species. The distribution and diversity of the ectomycorrhizospheric yeast species suggest a different community to that of the bulk-soil and rhizosphere of previously reported Nothofagus native forests, which could be related to exudation and nutrient availability, as well as environmental features. The data reported here are relevant for disturbance (natural and human-related) and management studies on Nothofagus forests.