Program Book - 27th Fungal Genetics Conference

FULL POSTER SESSION ABSTRACTS636. In vivo efficacy of antifungal treatment of Aspergillus terreus infections and the influence on host immune response in Galleria mellonella.Elisabeth Maurer 1 , Neill Browne 2 , Kevin Kavanagh 2 , Cornelia Lass-Flörl 1 , Ulrike Binder 1 . 1) Division of Hygiene and Medical Microbiology, Medical UniversityInnsbruck, Innsbruck, Tirol, Austria; 2) Medical Mycology Unit, Department of Biology, National Institute for Cellular Biotechnology, NUI Maynooth,Ireland.Background Infections with Aspergillus (A.) terreus are of major concern, due to its high likelihood of dissemination and its intrinsic resistance toamphotericin B (amB). The reason for this resistance is not known yet and the exact mode of amB action is still not fully understood. Recently, threeclinical isolates have been found to be amB susceptible in vitro. In order to investigate for differences in virulence of the respective isolates, and to test theamB efficacy in vivo, we used Galleria (G.) mellonella as an alternative model. Methods Virulence of amB resistant and amB susceptible A. terreus isolateswas compared in the invertebrate model G. mellonella. Further, we performed in vivo infection studies with combined antifungal therapy, and additionallywe investigated the potential effect of A. terreus infection and antifungal treatment on the G. mellonella immune system. Proteomic analysis of larvalhaemolymph, haemocyte counts and post-treatment infection studies were performed according to Kelly & Kavanagh 2011. Results Larval survival ratesdiffered for the various isolates tested, resulting in highest mortality rate for one amB susceptible isolate. Increase in survival was seen for all testedstrains, when larvae where treated with voriconazole. Treatment with amB only showed success in the groups infected with amB susceptible strains.Antifungal administration in larvae resulted in an increased number of circulating haemocytes. Proteomic studies showed different protein expression of anumber of proteins which have immune function. Pre-treatment of larvae with different antifungals also increased their resistance to Staphylococcus (S.)aureus infection, indicating a general ability of antifungals to prime the insect's immune system.637. Recognition and response to non self in Podospora anserina: a model of the fungal immune system. Marina Lamacchia, Annick Breton, AsenDaskalov, Frédérique Ness, Muhammad Khalid Salamat, Martine Sicault-Sabourin, Sven Saupe, Mathieu Paoletti. Institut de Biologie et GénétiqueCellulaire, UMR 5095 CNRS et Université Victor Segalen Bordeaux, Bordeaux, France.Recognition and response to non self, whether conspecific (between individuals from the same species) or heterospecifc (individuals from anotherspecies) is essential to many aspects of life including development, symbiosis and protection against pathogens. However distinction between thesemodes of recognition and responses is somehow blurred and can overlap. For instance in plants and animals Pathogen Recognition Receptors (PRRs) canoccasionally lead to auto-immune diseases in absence of pathogens. The NLR and NBS-LRR STAND proteins (a class of signal transduction proteins) aremajor PRRs in plants and animals, but these receptors remain largely unidentified in fungi. In Podospora anserina vegetative incompatibility (VI), aconspecific non self recognition process, leads to cell death and autophagy. VI is determined by interaction of het-c, encoding a glycolipid transfer protein,with members of the hnwd gene family encoding for STAND proteins. hnwd gene family members display the hallmarks of PRR encoding genes, includingfast evolution promoting production of a repertoire of receptors and ability to initiate a cell death reaction. het-c is also showing signs of fast evolution.We hypothesized that these genes are involved in pathogen recognition and that recognition of heterospecific non self would initiate a response similar tothe VI reaction. In this context, VI can be considered as an autoimmune disease. We undertook the task of deciphering the response of P. anserina toheterospecific non self, focusing our efforts on the description of the cellular response and the identification of fungal PRRs. We show that P. anserina’sresponses to another fungal species (Epicoccum nigrum), or to bacteria such as Serratia entomophila or Pseudomonas putida largely overlap the VIresponse at all levels investigated so far, including cellular morphology and cytology, requirement of autophagy and induction of the expression of a set ofgenes. We also provide evidence that het-c encoding the GLTP contributes to the response to non self and argue that this protein may be targeted bypathogen’s effectors. We develop efforts to identify PRRs involved in the initiation of these responses.638. Increased late blight resistance in HIGS potato lines targeting a P. infestans gene. N. Temme, C. Blumenhagen, A. Schwarzer, L. Weimer, K. Prenzler,T. Sauter, M. Pflugmacher, D. Stahl. KWS SAAT AG, Einbeck, Germany.Worldwide potato harvests are strongly diminished due the late blight disease caused by the oomycete Phytophthora infestans. The fungus-likeeukaryote and its interaction with its host plants has been extensively investigated during the last decades whereas diverse research projects focus on itsinfection processes. P. infestans colonizes potato as well as tomato plants and thereby differentiates haustoria. Those barriers between host cells andinvading pathogens are capable for exchange of nutrients, minerals but also of macromolecule like RNA molecules as shown for haustoria of parasiticplants. In oomycetes the exchange of effector protein from the pathogen to its host has been demonstrated. The movement of RNAi signals was shown inthe interaction of parasites with their host plants and can be used to target not only plant genes but also genes of plant invading organism in a mechanismcalled host-induced gene silencing (HIGS). This technique has been applied for gene silencing in plant parasites as well as in nematodes and fungi. Inoomycetes the RNA silencing is used as a standard method to characterize genes either by transient or by stable gene silencing and enzymes of the RNAimachinery have been identified. However, no efficient HIGS of oomycetes could be observed so far. We defined a P. infestans gene expressed duringdiverse developmental and infection stages of the oomycete as a HIGS target and could show that in planta expression of a HIGS hairpin constructtargeting this particular gene in transgenic potato lines can be employed for late blight control. Our results present the appropriate processing oftransformed HIGS hairpin constructs to siRNAs, their efficient function to silence the specific target gene sequence as shown in the reporter gene assaysand subsequently reduced infection levels and diminished disease spreading on those transgenic HIGS potato lines in the field.639. WITHDRAWNPopulation and Evolutionary Genetics640. Fertility in Aspergillus fumigatus and the identification of an additional ‘supermater’ pair. Céline M. O'Gorman 1 , Sameira S. Swilaiman 1 , Janyce A.Sugui 2 , Kyung J. Kwon-Chung 2 , Paul S. Dyer 1 . 1) School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom; 2)Molecular Microbiology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes ofHealth, Bethesda, Maryland, USA.Aspergillus fumigatus is an opportunistic human pathogen that causes a range of allergic and invasive diseases in severely immunocompromisedindividuals, with a very high mortality rate typically in excess of 50%. A functional sexual cycle was discovered in 2009 and a highly fertile ‘supermater’ pair,AFB62 and AfIR928, was later identified from a collection of 50 isolates. Here we describe the results of a larger, worldwide fertility screen and present anadditional ‘supermater’ pair. A set of 126 clinical and environmental A. fumigatus isolates were crossed against two Irish reference strains of each matingtype. A subset of the eight most-fertile strains was then tested in all pairwise combinations. The pairing of isolates 47-169 x 47-154 had consistently high278