Program Book - 27th Fungal Genetics Conference

FULL POSTER SESSION ABSTRACTScopies of AVR-Pia. Screening and analysis of cosmid clones indicated that two copies of the DNA-type transposon Occan (Occan 9E12 and Occan 3A3 ) werelocated on the same chromosome and three copies of AVR-Pia were located in between the two Occan elements. Ina168m95-1 contains a conservedOccan element, named Occan m95-1 , between sequences homologous to the 5’-flanking region of Occan 3A3 and the 3’-flanking region of Occan 9E12 . Inaddition, sequence polymorphisms indicated a homologous recombination between Occan 3A3 and Occan 9E12 , which resulted in Occan m95-1 . Based on theseobservations, we propose the hypothesis that homologous recombination in the two Occan elements leads to the deletion of AVR-Pia in Ina168m95-1.578. The interactome of pathogenicity factors in the rice blast fungus Magnaporthe oryzae. Xiaoying Zhou 1 , Yang Li 1 , Keerthi Jayasundera 2 , Anton Iliuk 2 ,Andy Tao 2 , Jinrong Xu 1 . 1) Dept. of Botany and Plant Pathology, Purdue University, West Lafayette, IN; 2) Dept. of Biochemistry , Purdue University, WestLafayette, IN.Rice blast is a disease of significant economic impact worldwide and a model system for studying fungal-plant interactions. To date, over 100pathogenicity factors have been identified in Magnaporthe oryzae. However, there is only limited knowledge about their relationships. To betterunderstand molecular mechanisms regulating plant infection processes, it is critical to identify protein-protein interaction networks important forpathogenesis. In this study, we characterized the interactome of selected pathogenicity-related proteins. The affinity purification and proteomicsapproaches were used to identify proteins that interact with over 60 known pathogenicity factors, including components of important signaling pathways.Protein-protein interaction maps were established for these pathogenicity factors based on affinity purification data and information about their orthologsin yeast. Co-immunoprecipitation, BiFC, or yeast two hybridization assays were used to verify the interactions of selected genes. For a number ofpathogenicity factor-interacting genes, gene knock-out mutants were generated to determine their functions in pathogenesis. To our knowledge, resultsfrom this study represent the first study of protein-protein interaction networks of pathogenicity factors in plant pathogenic fungi in M. oryzae.579. Interaction between phenolic and oxidant signaling in Cochliobolus heterostrophus. Benjamin A Horwitz 1 , Samer Shalaby 1 , Olga Larkov 1 , MordechaiRonen 2 , Sophie Lev 3 . 1) Department of Biology, Technion - IIT, Haifa, Israel; 2) Department of Plant Science, Tel Aviv University, Ramat Aviv, Israel; 3)Centre for Infectious Diseases and Microbiology, University of Sydney at Westmead Hospital, Westmead, NSW 2145, Australia.The transcription factor ChAP1 is an ortholog of yeast YAP1 in the maize pathogen Cochliobolus heterostrophus. ChAP1 migrates to the nucleus uponexposure to oxidative stress, inducing antioxidant genes such as thioredoxin and glutathione reductase [1]. ChAP1 also localizes to nuclei on contact withthe leaf and during invasive growth. Though reactive oxygen species are encountered on the host, ChAP1 nuclear retention can occur without oxidativestress. One of the signals responsible is provided by phenolic compounds [1-3]. Using a genetically-encoded ratiometric reporter of the redox state, weshowed that leaf extract and phenolics, despite their antioxidant properties, promote nuclear accumulation of ChAP1. To study this dual role of ChAP1 weidentified genes expressed in response to phenolics. Intradiol dioxygenase CCHD1 is rapidly upregulated, independent of ChAP1 [2]. Coumaric acid causedrapid and simultaneous upregulation of most of the b-ketoadipate pathway genes. Deletion of CCHD1 provided genetic evidence that protocatechuic acidis an intermediate in catabolism of many aromatics [3]. The activity of a structure series showed complementary requirements for upregulation of CCHD1and ChAP1 nuclear retention. The ability to metabolize a compound and ChAP1 nuclear retention are inversely correlated. To find additional genesinduced by phenolics, microarrays designed from the predicted coding sequences of the C. heterostrophus genome [4] were hybridized to probes madefrom RNA of cultures exposed to coumaric acid, or controls. Expression of about 90 genes from different pathways primarily for metabolism, for example,the b-ketoadipate, quinic acid and shikimic acid pathways, as well as transporters from different families was altered in response to coumaric acid. Theability to respond to phenolics and detoxify or metabolize them via the b-ketoadipate pathway confers an advantage to plant pathogens, and explains thepresence of at least two response pathways detecting these compounds. [1] Lev et al. (2005) Eukaryot. Cell 4:443-454; [2] Shanmugam et al. (2010) Cell.Microbiol. 12:1421-1434; [3] Shalaby et al. (2012) MPMI 25: 931-940; [4] Ohm et al. (2012) PLoS Pathog 8: e1003037. Supported in part by the IsraelScience Foundation. We thank Michal Levin and Itai Yanai for help with microarray hybridization.580. Mode of Action of Chitosan: Antifungal and Gene Modulator from Natural Origin. Luis V. Lopez-Llorca. Laboratory of Plant Pathology, Department ofMarine Sciences and Applied Biology, Multidisciplinary Institute for Environmental Studies (MlES) Ramon Margalef. University of Alicante, E-03080Alicante, Spain. email: lv.lopez@ua.es.Chitin is an abundant, easily obtained and renewable natural polymer, second only to cellulose. Chitin is a main structural component of barriers (cuticlesand cell walls) of invertebrates (crustaceans, insects and nematodes) and fungi. Its deacetylated form, chitosan, has higher solubility and is known to haveinteresting biological properties. Chitosan, as a polycation, permeabilises the fungal membrane in an energy dependent manner. Chitosan kills orcompromises the growth of important plant and human fungal pathogens. Unlike these fungi, fungal parasites of invertebrates (FPI, mainlynematophagous and entomopathogenic fungi), widely used biological control agents in sustainable agriculture, are resistant to chitosan. Perhaps as aresult of coevolution with their hosts, FPI have evolved chitosan-resistant low-fluidity membranes (high content of saturated FFA) and produce efficientchitosan degrading enzymes. Besides, chitosan activates fungus development (e.g. conidiation) and expression of FPI pathogenicity factors such as serineproteases involved in the degradation of host barriers. Using chemogenomic platforms with yeast (sensitive to chitosan) we have identified chitosanputative gene targets. One of them, ARL1, a member of the Ras superfamily that regulates membrane trafficking, confers chitosan sensitivity as a deletionmutant and resistance when overexpressed in yeast. Yeast ARL1 overexpression in the presence of chitosan mainly caused down-regulation of genesinvolved in cell energy generation (mitochondrial biology, ATP metabolism, energy storage metabolites) and associated by-products (oxidative stress, ROS)and up-regulation of cell cycle progression (mitosis/meiosis, chromatin dynamics and sporulation) genes. Neurospora crassa conidia germination isparticularly sensitive to chitosan. Low nutrient content of media increases chitosan driven membrane permeabilisation and N. crassa sensitivity. UsingRNAseq we have found differential expression of genes involved in membrane permeability, cell energy/ROS generation and cell division as a response ofN. crassa conidia to chitosan. Concluding, we are using cell and molecular approaches to fully understand the multimodal action of chitosan to fully exploitit in biotechnological and health applications.581. Unraveling the metabolome: how zombie ant fungi heterogeneously control ant brains. Charissa de Bekker, David Hughes. Biology and Entomology,Center for Infectious Disease Dynamics,Pennsylvania State University, State College, PA.Fungal entomopathogens rely on cellular heterogeneity during the different stages of insect host infection. Their pathogenicity is exhibited through thesecretion of secondary metabolites. Infection strategies of this group of environmentally important fungi can thus be studied by analyzing theirmetabolome. Next to generalists such as Beauveria bassiana and Metarhizium anisopliae, specialist species exist that are able to control host behavior.One of the most dramatic examples is the death grip of ants infected by Ophiocordyceps unilateralis, where ants are being used as a vehicle and finally biteinto vegetation before dying, aiding fungal spore dispersal after death. To establish this the fungus must not only overcome the immune system of thehost, but also manipulate the brain and atrophy the muscles. To date, most work on manipulation of host behavior has described the ant’s behavior,27th Fungal Genetics Conference | 263