VAAM-Jahrestagung 2012 18.–21. März in Tübingen

78This different behavior challenged us to find factors responsible for hostspecificity. We analyze segregants of a mixed-variety infection bothphenotypically and genotypically. Approximately 100 offspring of a crossof SRZxSRS are tested for virulence on maize and sorghum. Strains that donot lead to disease symptoms on sorghum and those showing full virulenceon sorghum are subjected to genotypic analysis by performing speciesspecificPCRs as well as an NGS approach. Genomic regions stemmingfrom the SRZ parent in non-virulent offspring and from the SRS parent invirulent offspring are expected to contain candidate genes for hostspecificity. This way, we identified the beginning of chromosome 7 as oneregion of interest. This region harbors an SRZ-specific gene (hsc1) that,when introduced into SRS, was shown to positively contribute to theaggressiveness of the recombinant strains on maize and negatively onsorghum.This shows that genotyping of mixed-variety offspring is a powerful toolto discover candidate genes involved in host specificity.FUV006Induction of manganese peroxidases of wood and leaf-littercolonizing agaricomycetes by olive oil mill residuesR. Reina* 1 , C. Liers 2 , R. Ullrich 2 , I. Garcia-Romera 1 , M. Hofrichter 2 ,E. Aranda 11 Estación Experimental del Zaidín CSIC, Soil Microbiology and SymbioticSystems, Granada, Spain2 International Graduate School of Zittau, Unit of EnvironmentalBiotechnology, Zittau, GermanyThe agroindustrial waste “alpeorujo” (also known as DOR; Dry OliveResidue) is derived from the extraction of olive oil and is produced in largequantities of both solid and liquid wastes in Mediterranean countries.The residue can be regarded as stimulating natural inductor foroxidoreductases mainly manganese peroxidases (MnP) produced by woodandlitter-decomposing Agaricomycetes. Not only these fungi are able togrow in the presence of nearly toxic amounts of phenol-rich DOR in solidstate cultures; but also the increased secretion of oxidative biocatalysts(e.g. up to 1 to 5-fold higher activities for MnP´s of Bjerkandera adusta,Auricularia auricula-judae and Agrocybe aegerita) helps them to detoxifythe persistent biopolymeric material. The later was evidenced by anincreased shoot and root dry weight of tomato plants grown in the presenceof fungal and enzymatically fermented DOR residues indicated a certaindetoxification effect (100% within 4 weeks for A. auricula-judae, B.adusta and A. aegerita). The biotransformation of DOR also could befollowed by changes in the molecular weight distribution of water-solublearomatics in the aqueous culture extracts (from 1.5 and 3.5 to 30 kDa) bysize exclusion chromatography obviously due to a de-polymerization butalso re-polymerization process.Further analysis of the de-novo peptides will allow us to clarify to whichMnP type these new representatives belong and which specific MnP genesare activated by DOR residues in the tested fungal organisms.FUP001The histone chaperone ASF1 is essential for sexualdevelopment in a filamentous fungusS. Gesing 1 , D. Schindler 1 , B. Fränzel 2 , D. Wolters 2 , M. Nowrousian* 11 Ruhr-Universität Bochum, Allgemeine und Molekulare Botanik, Bochum,Germany2 Ruhr-Universität Bochum, Analytische Chemie, Bochum, GermanyAscomycetes develop four major morphological types of fruiting bodiesthat share a common ancestor, and a set of common core genes most likelycontrols this process. One way to identify such genes is to search forconserved expression patterns. We analyzed microarray data of Fusariumgraminearum and Sordaria macrospora, identifying 78 genes with similarexpression patterns during fruiting body development. One of these geneswas asf1 (anti-silencing function 1), encoding a predicted histonechaperone. asf1 expression is also upregulated during development in thedistantly related ascomycete Pyronema confluens. To test whether asf1plays a role in fungal development, we generated an S. macrospora asf1deletion mutant. The mutant is sterile and can be complemented to fertilityby transformation with the wild-type asf1 and its P. confluens homologue.An ASF1-EGFP fusion protein localizes to the nucleus. To test if ASF1acts as a histone chaperone in S. macrospora, we used tandem-affinitypurification and mass spectrometry, and identified histones H3 and H4 asputative ASF1 interaction partners. The ASF1-H3 and ASF1-H4interactions were confirmed by yeast two-hybrid analysis. These dataindicate that the S. macrospora asf1 encodes a functional histonechaperone with a conserved role during fruiting body development.FUP002Inhibition of Verticillium dahliae in the presence or absence ofArabidoposis thaliana by Streptomyces lividansH. Meschke, S. Walter, H. Schrempf*University Osnabrück, FB Biologie/Chemie, Osnabrück, GermanyThe ascomycete Verticillium dahliae causes worldwide vascular wilt ofmany field and horticultural plants. During co-cultivation with the soilbacterium Streptomyces lividans, the germination of fungal conidia, andthe subsequent proliferation are impaired, and fungal conida andmicrosclerotia arise barely. Upon application of each individual strain toseeds of the model plant Arabidopsis thaliana, either the bacterial spores,or the conidia of each fungus germinate at or within the mucilage,including its volcano-shaped structures.The extension of hyphae from eachindividual strain correlates with the degradation of the pectin-containingmucilage. Proliferating hyphae spread to roots of the emerging seedlings.Plants, which arise in the presence of the Verticillium strain, have damagedroots cells, an atrophied stem and root, as well as poorly developed leaveswith chlorosis symptoms. A. thaliana seeds that have been mixed with theVerticillium strain together with S.lividans,have preferentially proliferatingbacterial hyphae within the mucilage, and at roots of the outgrowingseedlings. As a result, resulting plants have considerably reduced diseasesymptoms(1). Using HPLC and LC-MS, we succeeded to purify andcharacterize S.lividans metabolites that provoke the above-outlined effects.Additional results led to deduce that the identified metabolites inducemultiple cellular effects, which ultimately impair specific pathways forsignal transduction and apoptosis of the fungal plant pathogen (2)1) Meschke, H., and Schrempf, H. (2010) Microb Biotechnol 3: 428-4432) Meschke, H., Walter, S., and Schrempf,H. (2011) Environ Microbiol, in pressFUP003Physiological characterization and synthetic mediumdevelopment for a model rock-inhabiting black fungusC. Nai* 1,2 , H. Wong 3 , W. Broughton 1 , A. Gorbushina 1,21 BAM Bundesanstalt für Materialforschung und -prüfung, Department 4(Material und Umwelt), Berlin, Germany2 Freie Universität Berlin, Geowissenschaften und Biologie, Chemie &Pharmazie, Berlin, Germany3 British Columbia Institute of Technology, Burnaby, British Columbia, CanadaBlack fungi (a.k.a. black yeasts, meristematic or microcolonial fungi) arethe most stress-resistant eukaryotes known to date. These filamentousascomycetes are able to colonize bare rock surfaces and have evolvedpassive mechanisms to cope with multiple stresses like high solarirradiation, temperature extremes, low water activity and spare nutrientavailability, notably meristematic (isodiametric) growth and incrustation ofthe cell wall with melanins [1,2]. They are ubiquitous and often involvedin primary succession of terrestrial ecosystems by rock weathering and soilformation. Black fungi are therefore an interesting object to studymechanisms of stress resistance (e.g. in astrobiology studies) and are aswell used in applied research to prevent material colonization andbiodeterioration. Recently, it has been shown that an ancient clade of rockinhabitingfungi is ancestral to both symbiotic (e.g., lichenized fungi) andpathogenic black fungi [3], which makes them an attractive model to studyestablishment of symbiotic interactions and evolution of fungalpathogenesis in environmental isolates.Despite the ubiquity and importance of black fungi in the ecosystem andthe interest for research in both basic and applied directions, relativelylittle is known about their nutritional physiology. Moreover, black fungiare often difficult to cultivate in defined media. Here, we present dataproduced with the Biolog System [4] to generate a broad physiologicalprofile of the model black fungus Sarcinomyces petricola A95 uponcultivation under approximately 1’040 different growth conditions.Knowledge into growth physiology of our model microorganism was usedto develop a new ad hoc synthetic medium for A95, which we namedASM (for A95-specific medium) [5]. We compared growth of A95 inASM and in the undefined MEB (2% malt extract broth) and we discussthe obtained data in the light of the oligotrophic character (ability to growwith limited nutrients) of black fungi. We propose that A95 is able tosurvive in oligotrophic niches by compound re-cycling (cannibalisticmechanism) as observed by maintenance of a low metabolic activity uponabsence of primary nutrients (especially sulfur or phosphor sources).References:[1] Staley et al. (1982), Microcolonial Fungi: Common Inhabitants on Desert Rocks?, Science 215:1093-5.[2] Gorbushina (2007), Life on the rocks, Environmental Microbiology 9: 1613-1631.[3] Gueidan et al. (2008), A rock-inhabiting ancestor for mutualistic and pathogen-rich fungallineages, Studies in Mycology 61: 111-119.[4] Bochner (2003), New technologies to assess genotype-phenotype relationships, Nature ReviewsGenetics 4: 309-314.[5] Nai et al., manuscript in preparation.BIOspektrum | Tagungsband 2012