VAAM-Jahrestagung 2011 Karlsruhe, 3.–6. April 2011

interaction leads to the specific activation of two distinct silent secondarymetabolism gene clusters. Electron microscopy confirmed the intimateinteraction of the fungus and the bacterium. Full genome arrays of A.nidulans were applied to elucidate the whole genome response to thestreptomycete. Data on the molecular regulation of the involved secondarymetabolism gene clusters will be presented.FBV013Analysis of the Mating-type loci from the homothallicAscomycete Eupenicillium crustaceumS. Pöggeler* 1 , C.M. O’Gorman 2 , B. Hoff 2 , U. Kück 21 Institute for Microbiology and Genetics, Department for Genetics ofEukaryotic Microorganisms, Georg-August-University, Göttingen, Germany2 Department of General and Molecular Botany, Ruhr-University, Bochum,GermanyThe homothallic Eupenicillium crustaceum Ludwig is very closely related tothe penicillin-producer Penicillium chrysogenum, which is supposed toreproduce only asexually. However, recently strains of P. chrysogenum havebeen shown to carry either the mating type (MAT) locus MAT1-1 or MAT1-2suggesting a heterothallic breeding system (Hoff et al. 2008). To analyze themolecular basis of homothallism in E. crustaceum, we cloned and sequencedits MAT sequences. Two MAT loci, MAT1-1 and MAT1-2, reside in thegenome of E. crustaceum. MAT1-1 is flanked by conserved apn2 and sla2genes and encodes a homologue of the alpha-box domain protein MAT1-1-1, while MAT1-2 carries the HMG domain gene MAT1-2-1 and is flanked bya degenerated sla2 gene and an intact homologue of the P. chrysogenumORF Pc20g08960. To determine functionality of the E. crustaceum MATgenes, we demonstrate their transcriptional expression during vegetativedevelopment. Furthermore, the alpha-box domain sequence of MAT1-1-1and the HMG domain sequence of MAT1-2-1 were used to determine thephylogenetic relationship with other ascomycetes. Phylogenetic treesconfirmed strong relationships between the homothallic E. crustaceum andthe supposedly heterothallic P. chrysogenum.[1] Hoff, B. et al (2008): Eighty years after its discovery, Fleming's Penicillium strain discloses thesecret of its sex. Eukaryotic Cell 7: 465-470.FBV014Antifungal and Antibacterial activity of marineactinomycetes strains isolated from east and west coastalregions of IndiaR. Kumar*, S. Sathya, B.P. VenkateshMIcrobial BIotechnology, Bharathiar University, Coimbatore, IndiaExploration of secondary metabolites from microorganisms paved a way forthe identification of new antibiotics. Among the different classes ofmicroorganism, marine actinomycetes attract researchers havingeconomically valuable secondary metabolic compound of biologicalsignificance. Trichophyton rubrum is the most common dermatophytespecies and the most frequent cause of fungal skin infection in humansworldwide. It is the organism responsible for all type of tinea infection. Jockitch, athlete’s foot and ringworm are collectively said to be tinea. Symptomsof these infections vary depending on where they appear on the body. It isthe major concern because feet and nail infections caused by this organism isextremely difficult to cure.In the present study a total of 124 marine actinomycetes were isolated frommarine environment on Starch Casein Agar medium from different locationsof east and west coastal regions of India. All these isolates were testedagainst T. rubrum. Based on screening results, two potential actinomyceteswere selected and tested for their antifungal activity against dermatophytefungi T. mentagrophytes, against human bacterial pathogens Staphylococcusaureus, Bacillus subtilis, Salmonella typhi, Klebsiella pneumoniae,Enterococcus faecalis, Proteus vulgaris and against the yeast Candidaalbicans. These isolates showed remarkable antibacterial and antifungalactivity. Based on physiological, biochemical characterisation, these strainsbelong to the genus Streptomyces. According to the physiological study, thestrains had maximum growth rate at a NaCl concentration of 1g/L.These strains produced antifungal metabolite intracellularly undersubmerged fermentation conditions. The fermentation parameters such assubstrate concentration, pH, fermentation period and inoculam size wereoptimized by response surface methodology (RSM).The antibiotic substance was extracted with methanol and purified throughsilica gel column chromatography in chloroform: methanol (19:1) stepgradient.The UV visible spectrum of this active compound suggested beingalkaloidal nature. The NMR and X-ray crystallography studies of thiscompound are now in progress.FBV015Infection structures and mycotoxin induction ofFusarium graminearum on wheat floretsM. Boenisch*, W. SchäferMolecular Phytopathology and Genetics, Microbiology, Biocenter KleinFlottbek, Hamburg, GermanyQuestions: The mycotoxin producing fungal pathogen Fusariumgraminearum is the causal agent of Fusarium head blight (FHB) of smallgrain cereals in fields worldwide. Although F. graminearum is highlyinvestigated by means of molecular genetics, detailed studies about hyphaldevelopment during initial infection stages are rare. In addition, the role ofmycotoxins during initial infection stages of FHB is still unknown.Methods: We investigated the infection strategy of the fungus on differentfloral organs of wheat under real time conditions by constitutive expressionof the dsRed reporter gene in a TRI5prom::GFP mutant. Additionally, agreen fluorescent protein (GFP) coupled TRI5 promoter allowedvisualisation of trichothecene induction during infection. A tissue specificinfection behaviour and TRI5 induction were tested by using different floralorgans of wheat. Through combination of bioimaging and electronmicroscopy infection structures were identified and characterised. Inaddition, the role of trichothecene production for initial infection wasclarified by using a ΔTRI5-GFP reporter strain.Results: The present investigation demonstrates the formation of footstructures and compound appressoria by F. graminearum in addition to shortinfection hyphae. All infection structures developed from epiphytic runnerhyphae. Compound appressoria including lobate appressoria and infectioncushions were observed on inoculated caryopses, paleas, lemmas, andglumes of susceptible and resistant wheat cultivars. Subcuticular growth ofthe fungus originates from lobate appressoria and infection cushions. Aspecific trichothecene induction in infection structures was demonstrated bydifferent imaging techniques. Interestingly, a ΔTRI5-GFP mutant formed thesame infection structures and exhibited a similar symptom developmentcompared to the wild type and the TRI5prom::GFP mutant.Conclusions: The evidence for the formation of specialised infectionstructures by F. graminearum during infection on wheat florets reveals thatthe penetration strategy of this fungus is more complex than postulated todate. Monitoring of TRI5-induction demonstrates a specific induction oftrichothecenes in infection structures. A trichothecene deficient ΔTRI5-GFPmutant exhibits the same mode of infection and leads to wild type-likedisease symptoms on inoculated glumes and caryopses. We conclude thattrichothecene biosynthesis is induced in infection structures, but is neithernecessary for their development nor for formation of primary symptoms onwheat.FBV016The Role of the autophagy related genes Smatg4 andSmatg8 in the sexual development of Sordaria macrosporaO. Voigt*, S. PöggelerInstitute for Microbiology and Genetics, Department for Genetics ofEukaryotic Microorganisms, Georg-August-University, Göttingen, GermanyIn filamentous ascomycetes, autophagy is involved in several developmentalprocesses. Nevertheless, until now little is known about its role in fruitingbodydevelopment. We therefore isolated genes of the homothallicascomycete Sordaria macrospora with sequence similarity to theSaccharomyces cerevisiae autophagy-related genes ATG4 and ATG8encoding a cystein protease and an ubiquitin like protein which is astructural component of the autophagosome. This is the first characterizationof an ATG4 and ATG8 homologue in S. macrospora. We were able togenerate homokaryotic knockout, as well as complementation mutants in S.macrospora. The DSmatg4 and DSmatg8 deletion mutants were unable toform perithecia and are therefore sterile. By reintroducing Smatg4 andSmatg8 ectopically into the deletion strains the deletion mutant phenotypewas restored and the complemented strains were able to produce peritheciaagain. Our results indicate that Smatg4 and Smatg8 are directly or indirectlyinvolved in perithecia formation. Furthermore, we were able to localizeSmATG8 via N-terminal GFP fusion indicating that SmATG8-GFP islocalized to the autophagosome and is degraded in the vacuole along withspektrum | Tagungsband 2011