Program Book - 27th Fungal Genetics Conference

FULL POSTER SESSION ABSTRACTSCiuffetti 1,2 . 1) Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331; 2) Center of Genome Research and Biocomputing, Oregon StateUniversity, Corvallis, OR 97331.Pyrenophora tritici-repentis (Ptr) is a necrotrophic fungal pathogen of wheat causal to the disease tan spot and host-selective toxins (HSTs) produced byPtr are the primary factors that contribute to virulence. One of these HSTs, Ptr ToxA, is a necrosis-inducing, proteinaceous HST that is also present in thewheat pathogen Stagonospora nodorum. Ptr ToxB is a chlorosis-inducing, proteinaceous HST produced by Ptr with active orthologues expressed in thebrome grass pathogen, Pyrenophora bromi. Despite the presence of active, orthologous HSTs produced by other fungi, Ptr appears to have an advantage insome wheat growing regions in the world, surpassing in disease relevance the other necrotrophic pathogens that contain orthologous HSTs. To begin tounderstand the molecular mechanisms that underlie this advantage, we used RNA-seq-based transcriptome analysis to identify Ptr genes that aredifferentially regulated in planta early in the disease cycle (at thirty hours post-infection) as compared with those genes that are expressed in culture.Functional annotations of the differentially expressed-in planta transcripts reflect the requirements of the pathogen for host penetration, cell walldegradation and the need to counteract the host response to infection; these include CAZymes, peptidases, transporters, and loci with predicted oxidoreductaseactivities including peroxidases. In addition, putative secondary metabolite clusters and Ptr-specific proteins are also differentially regulated.These findings provide the basis for understanding the roles of these proteins in virulence and the possibility of revealing common transcriptionalregulatory elements activated by interactions with the host.562. Characterisation of genes in Quantitative Trait Loci affecting virulence in the basidiomycete Heterobasidion annosum s.l. Ake Olson, Yang Hu, IngaBödeker, Malin Elfstrand, Mårten Lind, Jan Stenlid. Dept Forest Mycology/Pathology, SW Univ Agricultural Sci, Uppsala, Uppsala, Sweden.Heterobasidion annosum sensu lato (s.l.), is a devastating root rot pathogen on conifers present all over the northern hemisphere that causes losses of500 of million Euro per year for forest owners. The H. annosum s.l. consists of five phylogenetic distinct species with different but overlapping hostpreferences. The genome sequence of one isolates from H. irregulare and H. occidentale preferentially infecting pine and spruce species, respectively havebeen obtained. Analysis of the progeny of a genetic cross of the sequenced isolates resulted in a genetic linkage map of 15 groups representing almost thecomplete chromosome set-up. These groups have been aligned and anchored to the physical map of H. irregulare. Quantitative trait loci (QTL) forvirulence on one-year-old Pinus sylvestris and two-year-old Picea abies seedlings were identified and positioned on the map allowing a straight forwardidentification of virulence candidate genes. Gene content and sequence divergence of the QTL regions will be presented. Detailed expression analysis ofvirulence candidate genes with Q-PCR and protein localisation with immunohistochemistry will deduce their role during infection.563. Elevation of FPP synthase activity in Trichoderma atroviride results in higher biocontrol abilities. Sebastian Graczyk, Urszula Perlinska-Lenart,Wioletta Gorka-Niec, Patrycja Zembek, Sebastian Pilsyk, Grazyna Palamarczyk, Joanna S. Kruszewska. Laboratory of Fungal Glycobiology, Institute ofBiochemistry and Biophysics, Warsaw, Poland.In this study we present a new method to obtain the Trichoderma strains with enhanced antifungal and biocontrol activities. The method is based on theincrease synthesis of the mevalonate pathway products. In this pathway some metabolites are produced such as terpenoids, trichodermin, harzianum A,mycotoxin T2, lignoren, ergokonin A and B and viridin which are known from their antifungal and antibacterial activities. All these compounds aresynthesized from farnesyl pyrophosphate (FPP) which is itself synthesized by farnesyl pyrophosphate synthase encoded by ERG20 gene. FPP is also asubstrate for dolichol and ergosterol production which are indirectly engaged in antimicrobial action. In this study we increased production of FPP in T.atroviride by overexpression of the yeast ERG20 gene. We based on the assumption that the increased activity of FPP synthase would stimulate productionof all products of the mevalonate pathway. Five transformants showed higher activity of FFP synthase. Simple screening of the hydrolytic properties of theERG20 transformants revealed that they grew faster on plates with polycarbohydrates as carbon sources. Detailed studies showed higher cellulotytic andchitinolytic activity of enzymes secreted to the cultivation medium by the transformed strains. Antifungal activity was examined by cultivation of plantpathogen Rhizoctonia solani in the atmosphere of volatiles liberated by the transformants and the control. We also analyzed growth of Pythium ultimumon plates which were previously overgrown by Trichoderma strains and were filled with their metabolites. Both experiment showed significantly strongerinhibition of growth of the pathogens by the transformed strains compared to the control. Since the above experiments revealed enhanced antifungalproperties of the transformed strains we performed plant tests using the bean Phaseolus vulgaris L.. Transformed strains increased both, the germinationrate and the size of plants growing in soil infected by Pythium ultimum compared to the control strain. To conclude, an increased activity of themevalonate pathway caused higher activity of hydrolytic enzymes and increased production of volatiles and secondary metabolites and that way boostedantifungal and biocontrol activities of the Trichoderma ERG20 transformants.564. The life history of Ramularia collo-cygni. Maciej Kaczmarek 1,2 , James Fountaine 1 , Adrian Newton 3 , Nick Read 2 , Neil Havis 1 . 1) Crop and Soil Research,Scotland's Rural College, Edinburgh, United Kingdom; 2) Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom; 3) Cell andMolecular Sciences, The James Hutton Institute, Dundee, United Kingdom.The filamentous fungus Ramularia collo-cygni causes the late season disease of spring and winter barley called Ramularia Leaf Spot (RLS). It has becomean increasingly important problem for European farmers in the past decade and has recently been reclassified as a major disease of barley in the UK. Thelack of apparent varietal resistance to the disease has led to significant amounts of fungicide being applied to crops in north western and central Europe inorder to maintain green leaf area and prevent significant yield loss. These factors have contributed to an increasing focus on achieving a betterunderstanding of the fundamental biology of this elusive pathogen in order to develop more successful strategies of RLS management. Therefore, diseasedevelopment throughout the life cycle of the host barley plant has been analysed by the employment of transgenic R. collo-cygni isolate, expressing theGFP reporter molecule, and confocal microscopy. We have been able to examine the previously uncharacterised seed-borne stage and illustrate the modeof fungal transmission into barley seedlings. We have also analysed the potential sexual reproduction in the fungus by utilising a range of correlativetechniques, such as cryo-scanning electron microscopy, confocal microscopy and light microscopy. Here we describe for the first time the nature ofspeculated spermogonial stage called Asteromella and in addition, present preliminary evidence suggesting the existence of a perfect stage that, iffunctional, could resemble closely related Mycosphaerella species.565. Mechanical stress sensing in Epichloë fungal symbionts during colonization of grasses. Kahandawa G.S.U Ariyawansa 1 , Rosie E. Bradshaw 2 , Neil A.R.Gow 3 , Nick D. Read 4 , Richard D. Johnson 1 , Duane P. Harland 5 , Christine R. Voisey 1 . 1) AgResearch, Grasslands Research Centre, Palmerston North, NewZealand; 2) BioProtection Centre, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand; 3) School of Medical Sciences,University of Aberdeen, United Kingdom; 4) Institute of Cell Biology, University of Edinburgh, United Kingdom; 5) AgResearch, Lincoln Research Centre,Christchurch, New Zealand.Epichloë festucae is an agronomically-important endophytic fungus that grows symbiotically within the intercellular spaces of temperate grass species27th Fungal Genetics Conference | 259