Marc J. Orbach
Division of Plant Pathology and Microbiology
Associate Professor

Forbes Building, Room 204
Phone: (520) 621-3764
Email: orbachmj@ag.arizona.edu

 

Visit these web-sites to learn more about Dr. Orbach and his research

 

   
Background and Interests
 
Research:
Saturate the Magnaporthe genome with DNA insertions to create a tagged gene library of the pathogen. Identify genes responsible for mutations in pathogenicity, and morphological development.

Identify effector genes in M. grisea that allow recognition and a host defensive response by the host plant.

Gene expression analysis of M. grisea and rice throughout infection using microarrays

Analyze global gene expression in Coccidioides posadasii (the Valley Fever fungus) during saprobic and parasitic growth using serial analysis of gene expression (SAGE). We will focus on understanding the process of dormancy within a resistant host which allows the fungus to evade host defenses and survive until the host becomes more conducive to pathogen growth via diminishment of the host immune system.

Identify genes important for the transition from saprobic to parasitic growth and continued growth during the parasitic phase, via gene knockout.

 
Selected Publications
 
Kellner, E.M., K.I. Orsborn, E.M. Siegel, M. A. Mandel, M.J. Orbach and J.N. Galgiani. 2004 (accepted) . Coccidioides posadasii contains a single 1,3- -glucan synthase gene that appears essential for growth. Eukaryotic Cell

Galagan, J.E. et al. 2003. The genome sequence of the filamentous fungus Neurospora crassa. Nature 422;859-868

Hamer L, HQ Pan, K. Adachi, M.J. Orbach, A. Page, L. Ramamurthy L and J.P. Woessner. 2001. Regions of microsynteny in Magnaporthe grisea and Neurospora crassa. Fungal Genet. and Biol. 33: 137-143.

Kelkar, H.S., J. Griffith, M.E. Case, S. F. Covert, R. D. Hall, C. H. Keith, J. S. Oliver, M. J. Orbach, M.S. Sachs, J.R. Wagner, M.J. Weise, J.K. Wunderlich, and J. Arnold. 2001. The Neurospora crassa Genome: Cosmid Libraries Sorted by Chromosome. Genetics 157:979-990

Orbach, M.J., L. Farrall, J.A. Sweigard, F.G. Chumley, and B. Valent. 2000. A telomeric avirulence gene determines efficacy for the rice blast resistance gene Pi-ta. Plant Cell. 12: 2019-2032

Mandel, M.A., G.G. Grace, K.I. Orsborn, F. Schafer, J.W. Murphy, M.J. Orbach, and J.N. Galgiani. 2000. The Cryptococcus neoformans gene DHA1 encodes an antigen that elicits a delayed-type hypersensitivity reaction in immune mice. Infect. Immun. 68: 6196-6201.

Aboudeh, R.O., M.J. Orbach, M.A. Mandel, A. Das and J.N.Galgiani. 2000. Genetic Transformation of Coccidioides immitis Facilitated by Agrobacterium tumefaciens. J. Infect. Dis. 181:2106-2110.

Mandel, M.A., V.W. Crouch, T.M. Harper, and M.J. Orbach. 1997. Physical mapping of the Magnaporthe grisea AVR1-MARA gene reveals the virulent allele contains two deletions. Mol. Plant-Microbe Interact. 10:1102-1105.

Diaz-Perez, S.V., V.W. Crouch, and M.J. Orbach. 1996. Construction and characterization of a Magnaporthe grisea bacterial artificial chromosome library. Fungal Genet. and Biol. 20:280-288.

Orbach, M.J., F.G. Chumley, and B. Valent. 1996. Electrophoretic karyotypes of Magnaporthe grisea pathogens of diverse grasses. Mol. Plant-Microbe Interact. 9:261-271.

Hamer, J.E., L. Farrall, M.J. Orbach, B. Valent, and F.G. Chumley. 1989. Host species-specific conservation of a family of repeated sequences in the genome of a fungal plant pathogen. Proc. Natl. Acad. Sci. USA. 86:9981-9985.


 



 

       
 
 


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