Plant-microbe features of Dendrobium fimbriatum (Orchidaceae) fungal community

To document in more details our knowledge of the fungal community associated to the Orchidaceae family, 25 cultivable fungal species were isolated from greenhouse apparently healthy Dendrobium fimbriatum var. oculatum Hook. adult plants. These fungi, were identified based on a molecular approach, belonging predominantly to Fusarium, Trichoderma, Colletotrichum, Curvularia and Didymella genera. To characterize their impact on plant growth and/or plant defense, their ability to produce different metabolites (phytohormones, siderophores) and hydrolytic enzymes, as well as their anti-phytopathogenic activity against Botrytis cinerea, Colletotrichum gloeosporioides and Fusarium oxysporum, were evaluated ex situ. Based on these criteria, three fungi, initially isolated from the roots, Fusarium sp., Trichoderma yunnanense, and Curvularia sp., showed a high potential to act on plant growth. Our results also show that an important number of isolates of the fungal community were able to produce phytohormones, siderophores, and had a similar hydrolytic enzyme production profile. Finally, these fungal abilities, studied ex situ, were analyzed to determine whether they can be used to classify the fungal partners as beneficial or detrimental to their host.