Fungal Genetics Reports Volume 42 Article 32 18th Fungal Genetics Conference Fungal Genetics Conference Follow this and additional works at: https://newprairiepress.org/fgr This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License. Recommended Citation Fungal Genetics Conference. (1995) "18th Fungal Genetics Conference," Fungal Genetics Reports: Vol. 42, Article 32. https://doi.org/10.4148/1941-4765.1362 This Supplementary Material is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Fungal Genetics Reports by an authorized administrator of New Prairie Press. For more information, please contact [email protected]. 18th Fungal Genetics Conference Abstract Abstracts from the 18th Fungal Genetics Conference, March 21-26, 1995 This supplementary material is available in Fungal Genetics Reports: https://newprairiepress.org/fgr/vol42/iss1/32 : 18th Fungal Genetics Conference Sponsor Acknowledgements 18th Fungal Genetics Conference National Science Foundation March 21-26, 1995 Novo Nordisk Biotech, Inc. Asilomar Conference Center Pioneer Hi-Bred International Pacific Grove, California American Cyanamid Company Abbott Laboratories SCIENTIFIC CHAIRS Dow Elanco Greg May Pierre de Wit Cibe-Beigy Corporation Merck & Co., Inc. Sponsor Acknowledgements National Science Foundation Novo Nordisk Biotech, Inc. Pioneer Hi-Bred International American Cyanamid Company Abbott Laboratories Dow Elanco Cibe-Beigy Corporation Merck & Co., Inc. Abstracts of Talks and Posters Table of Contents Talks: Signal Transduction in Yeasts, Fungi and Plants .............................................. 2 Talks: Gene Expression and Genome Structure I .......................................................... 4 Talks: Sexual and Asexual Reproduction ......................................................................... 7 Talks: Fungal Cell Biology and Morphogenesis ........................................................... 11 Talks: Plant and Animal Fungal Pathogenesis ............................................................ 14 Talks: Gene Expression and Genome Structure II ...................................................... 18 Posters I: Gene Expression/Genome Structure ........................................................... 22 Posters I: Signal Transduction .......................................................................................... 38 Posters I: Plant and Animal Fungal Pathogens ............................................................ 48 Posters II: Gene Expression/Genome Structure ......................................................... 72 Posters II: Gene Expression/Genome Structure ......................................................... 87 Posters II: Sexual and Asexual Reproduction .............................................................. 98 Posters III: Gene Expression/Genome Structure...................................................... 119 Posters III: Fungal Cell Biology ....................................................................................... 130 Posters III: Plant and Animal Fungal Pathogenesis ................................................. 143 Published by New Prairie Press, 2017 1 Fungal Genetics Reports, Vol. 42 [1995], Art. 32 Talks: Signal Transduction in Yeasts, Fungi and Plants Developmental signal pathways in Dictyostelium Rick Firtel. University of California, San Diego The cellular slime mold Dictyostelium discoideum grows as single-celled, mononucleated amoebae. When starved, the amoebae initiate a multicellular developmental program that results in the production of a mature fruiting body comprised of a stalk with a mass of spores on top. Approximately 4 hrs after removal or exhaustion of the food source, cells within the population produce and secrete extracellular cAMP. This interacts with G protein-coupled receptors that leads to chemotactic aggregation of ~10(5) cells to form a multicellular organism, activation of adenylyl cyclase and relay of the cAMP signal, and the activation of gene expression. Aggregation and several aspects of multicellular development have been shown to be controlled through several classes of serpentine receptors coupled to multiple heterotrimeric G proteins. Recent results have suggested that some of the responses that are regulated by cAMP receptors are G protein- independent, suggesting novel mechanisms by which the same ligand can elicit different developmental responses. Genes encoding eight distinct Ga protein subunits have been cloned and disrupted by homologous recombination. The function of some of these and the novel G protein-independent pathways will be discussed. Signal transduction in Saccharomyces cerevisiae and Ustilago maydis Flora Banuett and Ira Herskowitz. Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143 Cells respond to external stimuli by transducing these signals from surface to nucleus where gene activation then results in a variety of physiological responses. The MAPKs (mitogen activated kinases) and their upstream regulatory kinases are key players in signal transduction. They constitute a functional module consisting of the MAPK, its activator (MEK), and an activator of MEK (MEKK). S.-cerevisiae has several different MAPKs, each involved in a different pathway. The most intensively studied is the pheromone response pathway. Pheromones produced by haploid a or alpha cells bind to membrane receptors causing dissociation of a trimeric G protein into Galpha and Gbeta gamma. The latter activates the kinase cascade in an unknown fashion, which may involve Ste20 (another kinase), and Ste5 (a scaffold for the MAPK module). Ste20 is proposed to activate Ste11 (MEKK), which in turn activates Ste7 (MEK), which then activates Fus3/Kss1 (MAPK). These MAPKs then activate the transcriptional activator Ste12, which regulates expression of genes for cell fusion, cell cycle arrest, and morphological changes. Recent work indicates that pseudohyphal growth requires several components of this pathway. U. maydis codes for peptide pheromones and receptors that play a role in mating and filamentous growth. A MEK homolog (Fuz7) was identified necessary for the pheromone response and for tumor induction, which may reflect response to a plant signal. https://newprairiepress.org/fgr/vol42/iss1/32 DOI: 10.4148/1941-4765.1362 2 : 18th Fungal Genetics Conference Involvement of leucine-rich-repeat and protein kinases in disease resistance signal transduction in tomato John Salmeron(1), Caius Rommens(2), David Baulcombe(3) and Brian Staskawicz(2), (1)Ciba Agricultural Biotechnology, Research Triangle Park, NC 27709, (2)Dept. of Plant Pathology, University of California, Berekely, CA 94720, and (3)The Sainsbury Laboratory, Norwich Research Park, Colney Lane, Norwich NR4 7UH, UK. Eleven tomato mutants were isolated with altered response to the bacterial phytopathogen Pseudomonas syringae. Five lines carried mutations at Pto, a member of a clustered gene family predicted to encode serine/threonine protein kinases. Six lines carried mutations a second locus termed Prf and showed loss of sensitivity to the insecticide Fenthion as well as disease susceptibility. In contrast, pto mutants retain Fenthion sensitivity. Tight linkage between the Prf and Pto loci allowed cloning of candidate genomic DNA for the Prf locus. Within a 200-kbp contig spanning the Pto locus, a fragment was identified which detected a 1-kbp deletion in a prf mutant line. Sequencing this DNA revealed a gene predicted to encode a protein with nucleotide triphoshate binding (P-loop) and leucine-rich-repeat motifs, as contained in signalling proteins from a wide range of eukaryotes. To rapidly study members of Pto gene family, an assay for transient expression of these genes was developed based on infection of tomato leaves with recombinant derivatives of the Potato Virus X. Using this assay a Pto family member, designated Fen, was identified that confers Fenthion sensitivity. The predicted protein product of the Fen gene shows 80% amino acid identity to Pto and autophoshorylates in vitro, as does Pto. Therefore, tomato contains distinct kinases (Fen and Pto) specific for transduction of Fenthion and pathogen elicitor signals, and the Prf protein which functions in both signal transduction pathways. Mechanism and function of the oxidative burst in plant defense Chris J. Lamb, Plant Biology Laboratory, Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037 Treatment of bean or soybean cells with fungal elicitor causes a rapid insolubulization of pre-existing (hydroxy) proline-rich structural proteins in the plant cell wall. This insolubilization, which involves H2O2 - mediated oxidative cross-linking, is initiated within 2-5 min, and is complete within 10-20 min, and hence precedes the expression of transcription-dependent defenses. Oxidative cross-linking makes the cell wall refractory to digestion by microbial protoplasting enzymes and is strictly dependent on gene-for- gene mediated incompatibility in an isogenic setting. Thus stimulus-dependent oxidative cross-linking of wall proteins likely has an important function in the initial stages of plant defense. Cross-linking is substrate controlled by the rapid generation of H2O2 at the cell surface. We show that oxidative burst H2O2 also acts as a signal to trigger other key aspects of the hypersensitive responses deployed in the early stages of an incompatible interaction. Emerging evidence indicates that