Fungal Diversity is Not Determined by Mineral and Chemical Differences in Serpentine Substrates. Fungi inhabiting Western Alps serpentine substrates

Serpentine soils lead to strong selection of plant species due to their physico-chemical properties. The ability of serpentine soils to affect the evolution and distribution of organisms others than plants is less well known and there is currently little information about the serpentine fungal community. Asbestos minerals, often associated with serpentine rocks, can be weathered by serpentine-isolated fungi, suggesting an adaptation to this substrate. In this study, we have investigated whether serpentine substrates characterized by parent rocks with distinct mineral composition (including asbestos minerals) could select for different fungal communities. Amplicons were obtained from four serpentine samples, collected in the Western Alps, following direct DNA extraction and amplification of both the ITS1 and the ITS2 regions. The 454 pyrosequencing revealed some fungal taxa shared by the four ophiolitic substrates, but also highlighted several substrate-specific taxa. Bootstrap analysis of 454 OTU abundances indicated weak clustering of fungal assemblages from the different substrates, which did not match substrate classification based on exchangeable macronutrients and metals. These findings indicate the absence of a correlation between the substrate (mineral composition and available cations) and the diversity of the fungal community.