Program Book - 27th Fungal Genetics Conference

FULL POSTER SESSION ABSTRACTSdivergence of gene regulation with respect to light response or carbon specific regulation. Glycoside hydrolase genes follow the whole transcriptomepattern with carbon source being superior to light in terms of regulation. ENV1 in in part the G-protein beta subunit GNB1 were found to be crucial forcarbon source specific regulation of G-protein coupled receptors, genes involved in secretion, sulphur metabolism and oxidative processes as well astransporters. We conclude that clustered regulation of light responsive genes preferentially occurs upon growth cellulose and that ENV1 and to a lesserextent GNB1 play a role in carbon source dependent regulation of specific gene groups in light.432. Identification of regulators for enzyme production in Trichoderma reesei using genome-wide approaches. M. Häkkinen, M. Valkonen, N. Aro, M.Vitikainen, A. Westerholm-Parvinen, M. Penttilä, M. Saloheimo, T. Pakula. VTT, Espoo, Finland.Trichoderma reesei (anamorph Hypocrea jecorina) is an efficient producer of enzymes degrading cellulosic and hemicellulosic biomass. The cellulases andhemicellulases produced by the fungus are widely employed in industry, and also in biorefinery applications. Various environmental and metabolic factorstogether with the physiological state of the cell affect the enzyme production of T. reesei. Thus, a complex signalling cascade and regulatory network isneeded for the accurate timing of hydrolytic enzyme production and to control the pattern of enzyme activities produced. In previous studies, bothpositively and negatively acting regulatory factors for cellulase and hemicellulase genes have been characterised in T.reesei. In this study, an expressionmicroarray data on T. reesei cultivated in the presence of different carbon sources was analysed in order to identify additional regulatory genes forcellulase and hemicellulase production. In total, 28 putative regulatory factors for T. reesei cellulases and hemicellulases were identified and selected forfurther studies. The genes were overexpressed in T. reesei QM9414. Cultivated modified strains were tested for their ability to produce cellulases,xylanases and total secreted protein. Over-expression of seven of the genes led to increased production of cellulases and/or xylanases.433. The central core of the response to light and injury and their regulation by RNAi machinery in the filamentous fungus Trichoderma atriviride. J.M.Villalobos-Escobedo, N. Carreras-Villaseñor, A. Herrera-Estrella. LANGEBIO-CINVESTAV, Irapuato, Guanajuato, Mexico.All living organisms must sense and respond appropriately to different environmental stimuli in order to survive. Trichoderma atroviride is a filamentousfungus with wide adaptability to different environmental conditions and is considered a good morphogenetic model because it respond to light and injuryproducing asexual reproductive structures (conidia). The mechanisms used by this fungus to respond to these stimuli have been studied independentlyand models of perception and signal transduction for each stimulus have been proposed. In our research group, we found that the Ddcr2 mutant, involvedin small RNA biogenesis, is affected in conidiation in response to light and injury, indicating that conidiation is regulated by small RNAs. In this work wediscovered that when the Ddcr2 mutant receives simultaneously light and injury, it is able to conidiate. Based on this observation, we propose that there isa central core of genes needed to coordinate the response to both stimuli and in the Ddcr2 the signaling pathways act synergistically to achieve the correctexpression of these genes in order to conidiate. To test the above hypothesis we analyzed the transcriptome in response to light and injury of the wild type(WT), and identified 38 genes that have the same expression profile in response to the two stimuli, 19 of them are induced and 19 are repressed, calledthe central core genes, most of the up-regulated genes are involved in RNA processing, ribosome biogenesis, chromatin remodeling and other cellularprocesses indicating that this core regulates gene expression to respond to the stimulus. While genes that are repressed are mainly involved in lipid,carbohydrate and protein metabolic processes suggesting that a metabolic arrest is necessary to respond to both stresses. The expression analysis of thiscore of genes in the Ddcr2 revealed some of them are deregulated, but other genes respond similarly to WT in either light or injury in Ddcr2, so this groupof genes is regulated by the RNAi machinery.434. RNA-mediated Gene Silencing in Candida albicans: Reduction of Fungal Pathogenesis by Use of RNAi Technology. M. Moazeni 1 , MR.Khorramizadeh 2 , P. Kordbacheh 1 , H. Zeraati 3 , F. Noorbakhsh 4 , L. Teimoori-Toolabi 5 , S. Rezaie 1,2 . 1) Dept. of Medical Mycology & Parasitology, TehranUniversity of Medical Sciences, Tehran, Iran; 2) Dept. of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University ofMedical Sciences, Tehran, Iran; 3) Dep. of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; 4)Dept of Biology, Islamic Azad University, Varamin-Pishva Branch, Varamin, Iran; 5) Dept of Molecular Medicine, Biotechnology Research Center, PasteurInstitute of Iran, Iran.Background: The introduction of RNA silencing machinery in fungi has led to the promising application of RNAi methodology to knock down essentialvital factor or virulence factor genes in the microorganisms. Efg1p is required for development of a true hyphal growth form which is known to be essentialfor interactions with human host cells and for the yeast’s pathogenesis. In addition, it is responsible for positive regulation of the expression of severalhyphal-specific genes: SAP5, which encodes secreted aspartic proteinase, and ALS3, which encodes a multi-functional adhesive polypeptide. In this paper,we describe the development of a system for presenting and studying the RNAi function on the EFG1 gene in Candida albicans. Materials and Methods:The 19-nucleotide siRNA was designed on the basis of the cDNA sequence of the EFG1 gene in Candida albicans and transfection was performed by use ofa modified-PEG/LiAc method. To investigate EFG1 gene silencing in siRNA-treated cells, the yeasts were grown in human serum; to induce germ tubes asolid medium was used with the serum. Quantitative changes in expression of the EFG1 gene as well as two Efg1-associated genes, ALS3 and SAP5, wereanalyzed by measuring the cognate EFG1, SAP3 and ALS3 mRNA levels by use of a quantitative real-time RT-PCR assay. Results: Images taken byfluorescent microscopy method indicated the effectiveness of transfection. Compared with the positive control, true hyphae formation was significantlyreduced by siRNA at concentrations of 1 mM, 500 nM, and 100 nM (P227.05). According to REST® software data analysis, a considerable decrease in EFG1gene expression was observed when applying both 500 nM and 1mM of siRNA (P