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Jeff H. Chang Assistant Professor,
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Microbial genomics; Type III effector proteins of the plant pathogen, Pseudomonas syringae and the plant symbiont, Rhizobia.
Type III effector proteins are delivered from bacteria directly into host cells through the type III secretion system (TTSS). This system is used by both pathogens and symbionts during their interactions with hosts. This suggests that despite their drastically different lifestyles, they perturb similar host pathways.
The delivered type III effector proteins are required by pathogens for causing disease; strains incapable of delivering type III effectors are avirulent. I have screened several strains for each of their collections of type III effectors. I am using bioinformatic and proteomic approaches to determine how type III effectors function, their host targets, and how a particular strain uses its collection to cause disease on plants.
Very little is understood regarding the roles of the TTSS and type III effectors during symbiosis. It is however clear, that these molecules contribute towards establishment of host range. I am using high-throughput genomics methods to identify type III effectors of Rhizobia . I am interested in altering a collection of type III effectors within a strain to change its host range.
William Thomas (PhD expected 2011)
Jeff Kimbrell (PhD expected 2011)
Jason Cumbie (PhD expected 2011)
BI 212 Principles of Biology
MCB 554 Genome organization, structure and maintenance
MCB 637X Molecular host-microbe interactions
J. H. Chang, J. Urbach, T. Law, L. W. Arnold, A. Hu, S. Gombar, S. Grant, F. Ausubel, and J. L. Dangl (2005). A high-throughput, near saturating screen for type III effector genes from Pseudomonas syringae . PNAS. 102(7):2549-2554.
M. Lindeberg, J. Stavrinides, J. H. Chang, J. R. Alfano, A. Collmer, J. L. Dangl, J. T. Greenberg, J. W. Mansfield, D. S. Guttman (2004). Proposed Guidelines for a Unified Nomenclature and Phylogentic Analysis of Type III Hop Effector Proteins in the Plant Pathogen Pseudomonas syringae . Mol Plant Microbe Interact. 18(4):275-282.
A. U. Singer, D. Desveaux, L. Betts, J. H. Chang, Z. Nimchuk, S. R. Grant, J. L. Dangl and J. Sondek (2004). Crystal Structures of a Novel Type III Effector and its Chaperone Reveal Residues Required for Both Pathogen Virulence and Host Resistance. Structure. 12(2):1669-1681.
J. H. Chang, A. K. Goel, S. R. Grant, and J. L. Dangl (2004). Wake of the Flood: Ascribing functions to the wave of type III effector proteins of phytopathogenic bacteria. Curr. Opin. Microbiol. 7(1): 11-18.
J. H. Chang, Y. S. Tai, A. J. Bernal, D. T. Lavelle, B. J. Staskawicz, and R. W. Michelmore (2002). Functional Analyses of the Pto Resistance Gene Family in Tomato and the Identification of a Minor Resistance Determinant in a Susceptible Haplotype . Mol Plant Microbe Interact. 15(3): 281-291.
Z. Nimchuk, L. Rohmer, J. H. Chang, and J. L. Dangl (2001). Knowing the dancer from the dance: R-gene products and their interactions with other proteins from host and pathogen. Curr Opin Plant Biol. Aug;4(4):288-294.
J. H. Chang, C. M. Tobias, B. J. Staskawicz, and R. W. Michelmore (2001). Functional studies of the bacterial avirulence protein avrPto by mutational analysis. Mol Plant Microbe Interact. 14(4): 451-459.
J. H. Chang, J. P. Rathjen, A. J. Bernal, B. J. Staskawicz, and R. W. Michelmore (2000). AvrPto enhances growth and necrosis caused by Pseudomonas syringae pv. tomato in tomato lines lacking functional Pto or Prf genes. Mol Plant Microbe Interact. 13(5): 568-571.
J. P. Rathjen, J. H. Chang, B. J. Staskawicz, and R. W. Michelmore (1999). Constitutively active Pto induces a Prf -dependent hypersensitive response in the absence of avrPto . EMBO J. 18: 3232-3240.
C. M. Tobias, G. E. D. Oldroyd, J. H. Chang, and B. J. Staskawicz (1999). Plants Expressing the Pto Disease Resistance Gene Confer resistance to Recombinant PVX Containing the Avirulence Gene, AvrPto. Plant Journal. 17(1): 41-50.
S. R. Scofield, C. M. Tobias, J. P. Rathjen, J. H. Chang, D. T. Lavelle, R. W. Michelmore, and B. J. Staskawicz (1996). Molecular Basis of Gene-for-Gene Specificity in Bacteria Speck Disease of Tomato. Science. 274: 2063-2065.
