Fungi from the roots of the terrestrial photosynthetic orchid Himantoglossum adriaticum

Background and aims – Mycorrhizae have a pivotal impact on orchid growth and metabolism. We investigated the diversity of root fungal associates in Himantoglossum adriaticum H. Baumann, an endangered terrestrial orchid species with a central submediterranean distribution, growing in poor grassland, open woodland and garrigue. Methods – Fungal diversity in ten H. adriaticum adult plants collected from two geographically distinct protected areas of Central Italy was analysed by means of molecular methods. Total DNA from orchid roots was extracted and fungal ITS regions were PCR amplified using the primer pair ITS1F/ITS4; these were cloned and sequenced. Key results – A variety of fungal species including basidiomycetes and ascomycetes were found to be associated with the orchid under study. Among them, fungal taxa belonging to Tulasnellaceae were identified in most of the analyzed samples whereas ascomycetous fungi such as Helotiales, Sordariomycetes, and Exophiala were sporadically recovered. Trophic relationship and function of these fungal associates towards H. adriaticum are discussed.