Characterization of the fungal community in the tomato phyllosphere
S. Debenport (1), E. van der Knaap (1), B. MCSPADDEN GARDENER (1)
(1) The Ohio State University-OARDC, Wooster, OH, U.S.A.
Phytopathology 101:S41

While much is known about the diversity and activity of foliar pathogens, much less is known about fungal populations inhabiting healthy leaves. In this study we investigated fungal community composition in the tomato phyllosphere across four cultivars, three tissue types, and two sampling times. Fungi were isolated from healthy leaves and fruit and categorized using amplified ribosomal DNA restriction analysis (ARDRA) of the ribosomal internal transcribed spacer (ITS) region. Isolates representing each unique ARDRA profile were then selected and their ITS sequences sequenced. From a collection of 273 isolates, 30 distinct genomovars were observed, though only five of these individually represented more than 5% of the collection. These five included species of Cladosporium, Mucor, Epicoccum, and Alternaria. None of these predominant groups showed any significant variation by cultivar or field position. However, Epicoccum and Mucor were more prevalent at the later sampling time, and one group of Mucor was only found on mature leaves and fruit at the second sampling time. The activities of the isolates are currently being investigated in greenhouse bioassays for pathogenicity and biocontrol activity.