PARENT SESSION
Poster Session 30: Soil Ecology.
Wednesday, August 4 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
Mycorrhizae-pathogen interactions influenced by host genotype and type of pathogen.
Ronsheim, Margaret*,1, Green, Ellen1, 1 Vassar College, Poughkeepsie, NY
ABSTRACT- We examined the role that mycorrhizae may play in protecting host plants from soil fungal pathogens. In the first experiment we planted asexual propagules of three Allium vineale genotypes in the presence and absence of mycorrhizae and the pathogen, Sclerotium cepivorum (white rot), with some plants encountering the mycorrhizae first and others encountering the pathogen first. The results indicate that the interaction between mycorrhizae and the pathogen was strongly influenced by genotype of the host plant, the relative location of the mycorrhizae and the pathogen, and the age of the plants. This supports the hypothesis that mycorrhizal associations may play a role in mediating A. vineale-S. cepivorum interactions, but whether that role is positive, neutral, or negative will vary. The second experiment used a different pathogen (Sclerotium sp.) and included three plant genotypes from three different fields, one of which was same field from which the mycorrhizae and pathogen were isolated. There was no evidence that mycorrhizae altered the impact of this this pathogen species on A. vineale plants, although the pathogen had a greater negative impact on plant genotypes that were collected from the same field as the pathogen. These experiments demonstrate that while mycorrhizae may play a role in mediating some plant-pathogen interactions, it varies widely with type of pathogen, plant genotype, and the timing of the interaction.
Key words: pathogen, mycorrhizae, Allium vineale