Geographical and seasonal influences on the distribution of fungal endophytes in Quercus ilex

A systematic survey of the endophytic assemblages of Quercus ilex in centra l Spain has been performed, with the goal of evaluating the importance of g eographical and seasonal factors on these fungal communities. Four sampling sites were selected; one of them was sampled twice, in the spring and the autumn. The collected plant material consisted of bark, twigs and leaves fr om eight trees per site. Fungal strains were isolated with the use of a sur face-sterilization method with sodium hypochlorite. A total of 2921 fungal strains grouped into 149 'species' or morphological types were recovered. T he 10 dominant species, with isolation frequencies >1.5%, were Pyrenochaeta sp., Periconiella anamorph of Biscogniauxia mediterranea (De Not.) Kuntze, Pseudonectria sp., Cryptosporiopsis quercina Petrak, Alternaria alternata (Fr:) Keissl., two undetermined coelomycetes, Penicillium funiculosum Thom, Diplodia mutila Fr. apud Mont. and Ascochyta sp. Medians of fungal species per tree were significantly different among the sampled sites. The isolati on frequencies of the dominant species, as well as other less frequent spec ies, were significantly dependent on the sampling site. The degree of endop hytic infection and the diversity of fungal species were significantly high er in the spring. The frequencies of all dominant species at one of the sit es depended significantly on the season, except for C. quercina, Acremonium sclerotigenum (F & V Moreau ex Valenta) Gams. and D. mutila. Cluster analy sis of the whole endophytic mycoflora of the sampled trees suggested that t he geographical factor affects the endophytic distribution patterns more si gnificantly than the seasonal factor.