title: Identification of two fungal endophytes associated with the endangered orchid Orchis militaris L.
abstract: A survey of the endangered orchid Orchis militaris populations was carried out in north-eastern Italy. The occurrence of fungal root endophytes was investigated by light and electron microscopies and molecular techniques. Two main sites of presence were individuated in the Euganean Hills, differing as to the percentage of flowering individuals and of capsules completing maturity. Fluorescence microscopy revealed an intracellular cortical colonization by hyphal pelotons. Two ITS PCR products co-amplified. Sequencing revealed for the former an identity and a high similarity (99%) with a Tulasnellaceae (Basidiomycota) fungus found within tissues of the same host in independent studies in Hungary and Estonia, suggesting an interesting case of tight specificity throughout the Eurosiberian home range. The second amplicon had 99% similarity with Tetracladium species (Ascomycota) recently demonstrated as potential endophytes. TEM revealed two different hyphal structures. Double fungal colonization appears to occur in Orchis militaris and the possible requirement of a specific fungal partner throws light on the causes of this plant's rarity and threatened status.
authors.affiliation: Dipartimento di Biotecnologie Agrarie, Università di Padova, viale dell'Università 16, 35020 Legnaro, Padova, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Vendramin
authors.forename: Andrea
authors.initials: A
authors.lastname: Gastaldo
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tondello
authors.forename: Barbara
authors.initials: B
authors.lastname: Baldan
authors.forename: Mariacristina
authors.initials: M
authors.lastname: Villani
authors.forename: Andrea
authors.initials: A
authors.lastname: Squartini
mesh_terms: D001203:Ascomycota / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D001483:Base Sequence; D001487:Basidiomycota / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D056727:Endangered Species; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D029595:Orchidaceae / Q000382:microbiology* / Q000648:ultrastructure; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology / Q000648:ultrastructure; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D013559:Symbiosis / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer