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Some Orbach Lab Images. A genomics approach to understanding pathogenicity of the rice blast fungus, Magnaporthe oryzae. Marc Orbach Division of Plant Pathology and Microbiology University of Arizona.
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A genomics approach to understanding pathogenicity of the rice blast fungus, Magnaportheoryzae Marc Orbach Division of Plant Pathology and Microbiology University of Arizona
The Orbach Lab: Using Genetics and Genomics to understand pathogenicity in plant and animal pathogens Marc Orbach Division of Plant Pathology and Microbiology
Approaches • Mutagenesis, both random and directed to identify pathogenicity genes • Gene expression analysis to identify infection stage-specific genes • Comparative genomics to identify potential conserved pathogenicity factors • GFP reporter genes to observe expression
Rice Blast Infection Cycle Attachment Germination 1 hour Sporulation 3-5 days Colonization After 24-48 hours Appressorium Development 4-8 hours Melanization Penetration 24-48 hours http://www.ibwf.de/funagro_index.htm#Model Organism
Magnaporthe appressorial mutants generated by insertional mutagenesis Shape defects Bulbous hyphae- wall defects WT Failure to initiate development Failure to complete development Surface sensing defect?
Mutant testing on rice plants Spray inoculate 14 day rice seedlings (3-4 leaf stage) with 4 mls of conidial suspension (1x105 conidia/ml) Record data at 7 DPI. Cultivar 51583 70-15 : m28 : m32 : m33 : m31 : gelatin WT control
Coccidioides - a dimorphic animal pathogen Saprobic phase Parasitic phase • What regulates the dimorphic switch? • What is the environmental niche of the fungus? • What are fungal pathogenicity factors? • Do plant and animal pathogens have common pathogenicity factors?
Coccidioides Spherules in vitro Nuclear-localized GFP
Coccidioides in vivo spherules Nuclear-localized GFP