Transcript Some Orbach Lab Images - University of Arizona

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
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
Penetration 24-48 hours
Appressorium
Development
4-8 hours
Melanization
http://www.ibwf.de/funagro_index.htm#Model Organism
Magnaporthe appressorial mutants
generated by insertional mutagenesis
Shape defects
WT
Failure to initiate
development
Bulbous hyphaewall defects
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