Program Book - 27th Fungal Genetics Conference

FULL POSTER SESSION ABSTRACTSall these unique NPS genes of ND90Pr except the one for ID# 350779 were highly up-regulated in planta 12 hours post inoculation on barley cv. Bowman.Knockout mutants of the NPS gene for ID# 115356 and RNAi mutants of the NPS gene for ID# 140513 were significantly reduced in virulence on Bowman,but they had the same morphology and growth rate under the conditions of normal growth and oxidative/hyperosmotic stresses compared to the wildtype. These results indicate that these NPS genes are required for the high virulence of the pathotype 2 isolate on barley cv. Bowman. Functionalcharacterization of other unique NPS genes of ND90Pr will also be presented.320. Phylogenomics unveils secondary metabolites specific to mycoparasitic lineages in Hypocreales. C. Alisha Owensby, Kathryn E. Bushley, Joseph W.Spatafora. Botany & Plant Pathology, Oregon State University, Corvallis, OR.Hypocreales is an order characterized by a dynamic evolutionary history of interkingdom host jumping, with members that parasitize animals, plants, andother fungi. The monophyly of taxa attacking members of the same kingdom is not supported by molecular phylogenetics, however. For example,Trichoderma spp. and Elaphocordyceps spp. are both mycoparasitic, but are members of different families within Hypocreales, Hypocreaceae andOphiocordycipitaceae, respectively. In fact, both genera are more closely related to insect pathogens, than they are to each other. Multiple species ofTrichoderma have sequenced genomes, and recently genomes of several insect pathogens in Hypocreales have been completed (e.g. Metarhizium spp. andTolypocladium inflatum). The genus Elaphocordyceps represents a unique clade within Hypocreales, because whereas most species in the familyOphiocordycipitaceae are insect pathogens, most Elaphocordyceps parasitize truffles of the ectomycorrhizal genus Elaphomyces [Eurotiales, Ascomycota].To compare genes of a truffle pathogen with hypocrealean insect pathogens and mycoparasites, we sequenced the genome of Elaphocordycepsophioglossoides. Our draft assembly of the E. ophioglossoides genome is ~32 MB and has 10,779 gene models, 36 of which are predicted to producesecondary metabolites. We have identified three very large genes in E. ophioglossoides related to peptaibol producing nonribosomal peptide synthetase(NRPS) genes. Peptaibols, which disrupt osmoregulation by forming ion channels through lipid bilayers, have antibiotic and antifungal activity and are bestdescribed in Trichoderma spp. E. ophioglossoides and its beetle-pathogenic congener, T. inflatum, both possess three putative peptaibol synthetases whichwe identified through analysis of NRPS adenylation domains. Of the three peptaibol-specific domain clades, one is predicted to encode for thenonproteinogenic a-aminoisobutryic acid residues. We also show that, despite being very closely related, E. ophioglossoides and T. inflatum each possessthree different peptaibol-like genes, only two of which appear to be located in syntenic regions. The current distribution of fungi possessing peptaibolgenes is restricted to mycoparasitic lineages of Hypocreales and is generating hypotheses about the role of secondary metabolites in mycoparasitism.321. Genome and transcriptome sequence of the apomictic fungus Arnium arizonense (Podospora arizonensis). E. Coppin 1,2 , C. Drevet 3 , L. Peraza-Reyes 1,2 , D. Zickler 1,2 , E. Espagne 1,2 , J. Aït-Benkhali 1,2 , P. Silar 1,2,4 , A. E. Bell 5 , D. P. Mahoney 5 , R. Debuchy 1,2 . 1) Univ Paris-Sud, Institut de Génétique etMicrobiologie, Orsay, France; 2) CNRS, Institut de Génétique et Microbiologie, Orsay, France; 3) Univ Paris-Sud, eBio bioinformatics plateform, OrsayFrance; 4) UFR des Sciences du Vivant, Université Paris-7 Diderot, Paris, France; 5) Private Mycological Research, 45 Gurney Road, Lower Hutt, NewZealand.The homothallic fungus Arnium arizonense is closely related to the heterothallic Podospora anserina but displays several unique features. It is apomictic,i.e. dikaryotic croziers are formed inside the perithecia but neither karyogamy nor meiosis take place in the asci, although morphological changes in bothchromosomes and spindle pole bodies are reminiscent of those associated with meiosis in heteromictic Pezizomycotina. Instead of meiosis, the two nucleiundergo two mitoses and the resulting eight nuclei are enclosed in uninucleate ascospores, among which four mature normally, and four abort.Arrangement of the two ascospore types in individual asci is random (Mainwaring and Wilson, 1968, Trans Br mycol Soc, 51, 663). A. arizonense has twochromosomes, while most fungi in this group have seven chromosomes. Analysis of the genome sequence revealed that A. arizonense contained linkedcounterparts of the P. anserina mating-type genes, a structure that is typical of homothallic life style. Deletion of the mating-type locus resulted in the lossof perithecium formation, thus confirming the role of the mating-type genes in the fruit-body development. Genome annotation identified 11,165 genes,of which 476 undergo alternative splicing. Comparison of A. arizonense proteins with their orthologs in P. anserina revealed that A. arizonense genomecontains numerous pseudogenes. Direction for future work is to determine how apomixis takes place, as this process of asexual clonal reproductionthrough seeds has potential revolutionary applications in agriculture by allowing perpetuation of any important selected heterozygous genotype (reviewedby Ozias-Akins and van Dijk, 2007, Ann Rev Genet, 41, 509-537).322. Role of MAP kinase pathways in the pathogenicity of the wheat pathogen Mycosphaerella graminicola . Elisabetta Marchegiani 1 , Julie Vallet 1 , SiãnDeller 2 , Marc-Henri Lebrun 1 . 1) Bioger, INRA, Thiverval-Grignon, France; 2) Syngenta Limited, European Regional Centre, Priestley Road, Surrey ResearchPark, Guildford, Surrey, GU2 7YH, United Kingdom.Mitogen-activated protein kinases (MAPKs) are essential components of fungal signaling pathways involved in different developmental processes and arerequired for host plant infection. Mycosphaerella graminicola, the causal agent of Septoria tritici leaf blotch (STB) of wheat, has three MAPK pathways thatare all required for infection (MgFUS3 , MgHOG1, MgSLT2; Cousin et al., 2006; Mehrabi et al., 2006a, Mehrabi et al., 2006b). We showed that Mgfus3 nullmutants are non-pathogenic on intact wheat leaves (paint brush inoculation), but highly-reduced in pathogenicity when infiltrated into leaf tissues bysyringe injection (reduced necrosis, low number of pycnidia). This suggests that MgFUS3 is involved in fungal penetration, host colonization and pycnidiaformation. Mghog1 null mutants have pathogenicity defects similar to Mgfus3 null mutants. This result highlights that the role of HOG1 in pathogenicityon plants differs among fungi (Segmüller et al., 2007). Mgslt2 null mutants are fully non-pathogenic on inoculated wheat leaves either by paint brushinoculation or injection. This phenotype is unusual among slt2 null mutants from other fungi. Therefore, Mycosphaerella graminicola MAPK pathways mayhave evolved to control regulatory networks differing from other fungal plant pathogens. To identify which genes are under the control of the MgSLT2signaling pathway, we are developing different transcriptomics analyses. Expression profiling relies on the comparison of transcriptomes of Mgslt2 nullmutants and wild type strains grown under conditions corresponding to either an active or an inactive SLT2 pathway. Additional transcriptomics analyseswill be performed using an allele encoding a conditionally active MAPKK expressed under the control of an inducible/repressible promoter. Genes whoseexpression requires an active SLT2 MAPK will be further studied for their role in development and infection using reverse genetics. Cousin et al. (2006),Molecular Plant Pathology 7(4): 269-278. Mehrabi et al; (2006a), Molecular Plant-Microbe Interactions 19(4): 389-398; Mehrabi et al. (2006b), MolecularPlant-Microbe Interactions 19(11): 1262-1269; Segmüller et al. (2007), Eucaryotic Cell 6(2) 211-221.323. WITHDRAWN324. Ancient and abundant MITEs in epichloae genomes. Damien Fleetwood 1 , Chris Schardl 2 , Carolyn Young 3 . 1) Forage Improvement Section,AgResearch, Auckland, New Zealand; 2) Dept of Plant Pathology, University of Kentucky, Lexington, KY; 3) Forage Improvement Division, Samuel RobertsNoble Foundation, Ardmore, OK.27th Fungal Genetics Conference | 199