Diversity of endophytic fungi isolated from cherry (Prunus avium).

Endophytic fungi are currently considered as symbionts which can colonize a wide range of hosts and do not induce any pathological signs. The main aim of this study was to identify the endophytic fungi colonizing different organs (root, twig and leaf) of cherry (Prunus avium). Samples were collected from eight-year-old trees of the Hungarian cultivar ‘Peter’ grafted on 11 different rootstocks. After surface sterilization samples were put on potato dextrose agar and outgrowing fungal colonies were visually classified after 1 and 2 weeks. Then monosporation and monohyphation technique was applied to generate single colonies of each individual fungus, and the isolated colonies were classified morphologically. Molecular identification at genus or species level was performed by applying the polymerase chain reaction (PCR) to amplify a nuclear ribosomal internal transcribed spacer region (ITS) and by sequence comparison of the PCR products. A total of 150 endophyte strains were isolated from 4500 tissue segments. About 25 species were identified as belonging to the genera Acremonium, Alternaria, Botryotinia, Aspergillus, Chaetomium, Cladosporium, Embellisia, Epicoccum, Fusarium, Glomerella, Macrophomina, Neonectria, Phoma, Diaporthe/Phomopsis, Pyronema, Rhizoctonia, Rhizopycnis, Rosellinia and Xylaria. Endomycota showed the highest diversity in roots, while in twigs and leaves we predominantly found Alternaria. Further analyses are being carried out to verify which endophytes can be used to improve the physiological functions and tolerance threshold of the grafted trees against environmental stresses.