PARENT SESSION
Poster Session #25: Mycorrhizal Fungi and Root Processes.
Tuesday, August 6. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

The arbuscular mycorrhizal fungal soil protein glomalin influences hyphal palatability.

Rillig, Matthias^*,1, Klironomos, John², ¹ University of Montana, Missoula, MT² University of Guelph, Guelph, Ontario, Canada

ABSTRACT- Arbuscular mycorrhizal fungi (AMF) are crucial to the functioning of terrestrial ecosystems. In order for these obligate biotrophs to be effective in the environment, it is essential that their extraradical mycelium be protected against fungivores; otherwise the continuity of carbon flux from root to hyphal tip is interrupted. AMF hyphae are less palatable to hyphal grazers compared to other hyphae, but the mechanism is unknown. Here we present evidence that glomalin, a glycoprotein produced by AMF, may be responsible for this protection afforded AMF. Addition of glomalin to yeast in feeding trials significantly reduced palatability of yeast to the collembolan Folsomia candida (as measured by fecal pellet counts, oviposition). Also, glomalin production by four AMF species (Glomus mosseae, G. intraradices, G. etunicatum, and Gigaspora gigantea) was highly negatively correlated with palatability of these fungi to F. candida. Glomalin production explained 95% of the variability of fecal pellet counts among the species, and 90% of the variability of second-generation egg production by F. candida exclusively reared on a diet of the respective fungus. This is some of the first evidence concerning AMF hyphal biochemistry effects on fungivory. At the same time this result points to a potentially crucial function of this protein in the biology of AMF; while the protein is important in soil ecology, a clear role in AMF biology has not been evident.

KEY WORDS: mycorrhiza, soil , fungivory, fungi