Program Book - 27th Fungal Genetics Conference

FULL POSTER SESSION ABSTRACTSleaving the molecular processes from the fungal point of view unresolved. To start unraveling the mechanisms underlying this phenomenon we arecombining metabolite profiling with an ex vivo insect tissue culturing system that allows us to study fungal metabolites secreted in different parts withinthe host. Using this technique we established that B. bassiana and M. anisopliae, and O. unilateralis heterogeneously react to brain and muscle tissue bysecreting a significantly different array of metabolites. The combination of these approaches with a concrete understanding of the host-parasiteinteraction in nature is allowing us to understand both the diversity of secondary metabolites as well as make discoveries regarding the temporal dynamicsthese fungi employ when releasing metabolites that affect the host. This project is financed by the Marie Curie International Outgoing Fellowships andPenn State University .582. Gene expression of fungal aldehyde dehydrogenases in ectomycorrhiza. Catarina Henke 1,2 , Kartrin Krause 1 , Erika Kothe 1 . 1) Friedrich SchillerUniversity of Jena, Institute of Microbiology, Microbial Communication, Neugasse 25, D-07743 Jena, Germany; 2) Max Planck Institute for ChemicalEcology, International Max Planck Research School, Hans-Knöll-Strabe 8, D-07745 Jena, Germany, chenke@ice.mpg.Ectomycorrhizal fungi form a mutual symbiosis with trees and perform important functions in the ecosystem, particularly improving plant growth,nutrient supply and plant protection against pathogens. The molecular level of the association between the basidiomycete fungus Tricholoma vaccinumand the specific host spruce (Picea abies) is studied to investigate the molecular mechanisms of interaction. Differential display analysis revealed a fungalaldehyde dehydrogenase encoding gene ald1 from the basidiomycete T. vaccinum specifically expressed in ectomycorrhiza during interaction with thecompatible host. Ald1 has a key function in the detoxification of alcohols and aldehydes occurring in mycorrhizal biotopes and is involved in production ofthe phytohormone indole-3-acetic acid. Gene regulation of ald1 is monitored via quantitative RT-PCR analyses. Transcription level was increased in themutualistic association and could be stimulated by different external supplements, namely alcohols and aldehydes. The ald1 overexpressing mutantsgenerated by Agrobacterium tumefaciens mediated transformation showed increased ethanol stress tolerance. Linkage between gene transcription leveland phenotypic characterization will elucidate deeper understanding of biological function, particularly of the possible pathways of auxin synthesis, andwill allow better understanding of aldehyde dehydrogenases in ectomycorrhiza.583. Interaction of ectomycorrhizal fungi with environment. Katrin Krause, Ines Schlunk, Erika Kothe. Institute of Microbiology, Friedrich SchillerUniversity, Jena, Thuringia, Germany.Ectomycorrhizal fungi play an important role in the biogeochemical cycle, act as decomposers and environmental indicators. Therefore they interact withdifferent compounds of the environment like secondary metabolites of plant and soil living microorganisms, heavy metals and xenobiotics. Differentenzymes and transporters are involved in these processes. One of these transporters, multidrug and toxic compound extrusion (MATE) mte1 of theectomycorrhizal fungus Tricholoma vaccinum, was upregulated during symbiosis. By heterologous expression of mte1 in Saccharomyces cerevisiae,different metals, xenobiotics and secondary metabolites were identified as substrates for the MATE transporter. Furthermore, a retrotransposon retroshowed an upregulation during the symbiosis with spruce. After long-term cultivation of the fungus an additional copy of the retrotransposon wasdetectable by Southern blot analyses in the fungal genome, showing transposition during co-cultivation with the plant. Since the fungus is prone toexperience some plant-derived defense, the induction of transposition might be caused by plant induced stress.584. Genetic exchange in an arbuscular mycorrhizal fungus; Rhisophagus irregularis. Pawel Rosikiewicz 1 , Ian Sanders 2 . 1) Department of Ecology andEvolution, University of Lausanne, Lausanne, Switzerland Pawel.Rosikiewicz@unil.ch; 2) Department of Ecology and Evolution, University of Lausanne,Lausanne, Switzerland, Ian.Sanders@unil.ch.Rhizophagus irregularis is a model species of an arbuscular mycorrhizal fungi (AMF). The AMF forms symbiotic relationship with roots of land plants,improving plant growth and protecting plants against parasites. R. irregularis is a particularly important species of AMF because it colonizes roots of mostof crop plants such as rice, potato and wheat. However, different isolates of this fungus can affect plant phenotype differently. Moreover, it recently hasbeen shown that two isolates of AMF can exchange genetic material, a process that can alter both, plant and fungal phenotypes. R. irregularis, is acoenocytic organism, which means that many nuclei coexist and can move in the common cytoplasm. The genetic exchange between two AMF isolatesoccurs via vegetative hyphal fusion. However, unlike in most fungi AMF produces multinucleate spores and it has been shown that each isolate of R.irregularis carries genetically different nuclei, which are maintained in successive AMF generations. What is unknown is the fate of parental nuclei after thegenetic exchange, how many parental nuclei are exchanged and whether the mix of nuclei is random. In addition the nuclei are exchange with thesurrounding cytoplasm. This lead to a question whether mitochondria from both parental isolates are transmitted to the offspring. In order to answerthose questions I performed an in vitro experiment, where 6 isolates of R. irregularis were grown in pairs and allowed to fuse and exchange theircytoplasm. Subsequently, spores from all in vitro cultures were collected and used to establish 215 potentially crossed AMF lines. Each AMF line wasestablished from a single spore. Fifty-seven of this newly produced AMF lines where genotyped, resulting in identification of 40 crossed AMF lines. Allgenotyped single spore lines carried only one mitochondrial haplotype. Moreover, all the progeny of a given pair of parental AMF isolates received themitochondria from the same parent.585. A surface hydrophobin in ectomycvorrhiza interaction. Dominik Senftleben, Katrin Krause, Erika Kothe. Friedrich-Schiller-Universitat, Jena, Germany.Hydrophobins are small-secreted proteins with low sequence homology. However, all proteins contain eight cysteines, which form disulfide bridges.There are two classes of hydrophobins, depending on their solubility, which have a broad range of functions such as cell wall integrity, coveringconidiospores, adhesion in pathogenic and ectomycorrhiza interactions. Therefore, hydrophobins as well as other genes in a mutual symbiosis aredifferential expressed. We showed this for hydrophobin tthyd1, which is up regulated in the Hartig’net during interaction of Tricholoma terreum with pine.We investigate hydrophobins in T. vaccinum, a widely spread basidiomycete (Agaricales - Tricholomataceae) which forms ectomycorrhiza with spruce. Theestablishment of a high compatible mycorrhiza needs in a co-culture system about one month, in comparison to a low compatible one, which needs aboutfour months. We know which hydrophobin T. terreum regulates specifically in both interactions. Is this also the case for T. vaccinum and can we improvethe low compatible interaction by heterologous or over expression? So far, we investigated five T. vaccinum hydrophobins and 17 in the Tricholoma genusin total. We also want to show via quantitative Real-Time PCR in which stage of the life cycle respectively symbiotic interaction T. vaccinum produceshydrophobins, what kind of role they play with respect to function in the symbiotic tissue and their regulation under heavy metal stress. Due to the factthat T. vaccinum is a k-strategist and the triggers for fruiting body development are unknown, over expression of hydrophobin protein are important tocharacterise their properties. Also in silico analyses are done such as protein-protein complexes with HADDOCK (High Ambiguity Driven protein-proteinDOCKing) for rodlet layer formation and phylogenetic trees (ITS, hydrophobin) to understand how the evolution of the host, fungus and its hydrophobinstook place. (Identification of a hydrophobin gene that is developmentally regulated in the ectomycorrhizal fungus Tricholoma terreum., Manke et al., App.and Environ. Microbiol., 2002 HADDOCK: a protein-protein docking approach based on biochemical and/or biophysical information. Bonvin et al., J. Am.264