Einfluss von Bodenbakterien auf Transkriptom und Proteom des Mykorrhizapilzes Amanita muscaria

Microscopy of ectomycorrhizal roots directly sampled from the field has revealed the presence of bacteria in the hyphal sheath, in the Hartig net region and on soilcolonising extramatrical hyphae. Some of these rhizosphere bacteria, named mycorrhiza helper bacteria, have been shown to improve hyphal growth and mycorrhiza formation. The mechanisms behind these processes are currently unknown. We have focused on the effect of two streptomycete strains, that induce hyphal growth and mycorrhization, on the gene and protein expression of Amanita muscaria (fly agaric). Total RNA isolated from A. muscaria mycelium, co-cultured with the streptomycete strain 505, has been used for cDNA synthesis and for the construction of a subtracted cDNA bank. Differential expression of the subtracted cDNAs has been analysed by macroarrays and partially verified by Northern hybridisation. Changes in protein patterns between streptomycete-induced A. muscaria mycelium and of aseptic fungal cultures have been analysed by twodimensional gel electrophoresis and peptide mass spectrometry. Most of the differentially expressed fungal genes show homology to members of signal transduction pathways. Others are homologous to genes involved in metabolism, cell proliferation and cell structure. This implies that the fungus-streptomycete interaction is connected with changes in signalling pathways that lead to an altered fungal physiology.