Document: MEG-3-57-8

Interactions between mycorrhizal fungi and fungal pathogens and their impact on asexual propagules of Allium vineale.

RONSHEIM, M.L.* and W.MOSES

Vassar College, Poughkeepsie, NY 12604-0513 USA ¹

Abstract:
It has been proposed that, in addition to increased P uptake, mycorrhizae may play an important role in protecting host plants from pathogens. We planted asexual propagules of Allium vineale in the presence and absence of both mycorrhizae and Sclerotium cepivorum, a soil fungal pathogen specific to the genus Allium, using a factorial design. Three plant genotypes were used, one from the same field from which the mycorrhizae and pathogen were isolated (genotype A), and two from other field sites (genotypes B and C). As found in previous experiments, an early parasitic effect of mycorrhizal colonization was seen on Allium vineale growth. In addition, the presence of mycorrhizae significantly reduced the percent infection of Sclerotium cepivorum, as no colonization by the pathogen was found in roots previously colonized by mycorrhizae. This benefit was genotype dependent, as genotype A did not survive if both mycorrhizae and the pathogen were present. Thus the genotype of the host plant strongly influenced the interaction between mycorrhizae and Sclerotium cepivorum. Overall these results support the hypothesis that mycorrhizal associations play an important role in mediating plant-pathogen interactions.

Keywords: mycorrhizae, soil pathogen

This abstract is being presented at: 3:30 PM in session:
MYCORRHIZAL FUNGI