Fungal Diversity of Selected Habitat Specific Species (Orchidaceae) in the Central Highlands of Madagascar.

About 90% of species are endemic to the biodiversity hotspot of Madagascar. This terrestrial habitat-specific genus received little study for fungal diversity to support conservation. We evaluated the diversity of culturable fungi of 11 species and soil characteristics from six sites spanning a >40 km radius in and along the region's inselbergs. Peloton-forming fungi were grown in vitro from root/protocorm slices and positively identified using DNA sequencing. The fungal diversity was then correlated with soil pH, NON, P, and K. All species harbored either putative mycorrhizal associates in the complex or Hypocreales fungi. Operational Taxonomic Units (OTUs) were most prevalent in all soil types while OTUs were found in species inhabiting granite/rock outcrops in moist soil (seepage areas). Most species were present in soil with low NON and P levels with diversity of mycorrhizal fungi inversely correlated to NON levels. Of the different orchid life stages sampled, only one species () yielded putative mycorrhizal fungi from juvenile stages. As diversity of mycorrhizal fungi of spp. was negatively correlated with NON, and majority of the studied taxa were found in soils with low NON and P contents, reintroduction studies must include analysis of N and P in detail. For the first time, we showed that the assemblage of culturable fungi in the roots of habitat-specific species of (Orchidaceae) are intimately tied to specific soil characteristics.