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University of Nebraska–Lincoln

Plant Pathology

J.R. Alfano's Research

Dr. Alfano's research interests are concerned with understanding how bacterial pathogens cause disease in plants and how their strategies differ from the strategies employed by bacterial pathogens of animals. Research in his laboratory primarily is focused on understanding a specialized protein secretion apparatus, called the type III secretion system, present in gram-negative bacterial pathogens of plants and animals. Type III systems secrete multiple virulence proteins, some of which are transferred directly into eukaryotic cells in a contact-dependent manner. Acquisition of a type III secretion system appears to be a key adaptation that allowed many gram-negative bacteria to become pathogens – mutants with a disabled type III system are essentially nonpathogenic.

Dr. Alfano's research group studies the type III secretion system present in the bacterial plant pathogen, Pseudomonas syringae. P. syringae is a leaf-spotting pathogen whose various strains display host specificity: Different strains are only capable of causing disease in certain plants. The group studies the interactions of P. syringae with such crop plants as tobacco, soybeans, and tomato, as well as the interactions of P. syringae with the genetically amenable plant Arabidopsis. Studying the interaction of P. syringae and Arabidopsis is particularly attractive because it allows them to relatively easily identify key molecular attributes of both the pathogen and the host with the long-term goal of understanding the intimacies involved in bacterial parasitism.

Most recent publications

  • Fu, Z.Q., M. Guo, B. -r. Jeong, F. Tian, T. E. Elthon, R.L. Cerny, D. Staiger, and J. R. Alfano. 2007. A type III effector ADP-ribosylates RNA-binding proteins and quells plant immunity. Nature 447: 284-288.
  • Vencato, M., F. Tian, J. R. Alfano, C. R. Buell, S. Cartinhour, G. A. DeClerck, D. S. Guttman, J. Stavrinides, V. Joardar, M. Lindeberg, P. A. Bronstein, J. W. Mansfield, C. R. Myers, A. Collmer, and D. J. Schneider. 2006. Bioinformatics-enabled identification of the HrpL regulon and type III secretion system effector proteins of Pseudomonas syringae pv. phaseolicola 1448A. Mol. Plant Microbe Interact. 19: 1193-1206.
  • Fereirra, A.O., C.R. Myers, J.S. Gordon, G.B. Martin, M. Vencato, Alan Collmer, M.D. Wehling, J.R. Alfano, G. Moreno-Hagelsieb, W.F. Lamboy, G. DeClerck, D.J. Schneider, and S.W. Cartinhour. 2006. Whole-genome expression profiling defines the HrpL regulon of Pseudomonas syringae pv. tomato DC3000, allows de novo reconstruction of the Hrp cis element, and identifies novel co-regulated genes. Mol. Plant Microbe Interact. 19: 1167-1179.
  • Fu, Z.Q., M. Guo, and J.R. Alfano. 2006. The Pseudomonas syringae HrpJ is a type III-secreted protein that is required for plant pathogenesis, injection of effectors, and for secretion of the HrpZ1 harpin. J. Bacteriol. 188: 6060-6069.
  • Fu, Z.Q., M. Guo, and J.R. Alfano. 2006. The Pseudomonas syringae HrpJ is a type III-secreted protein that is required for plant pathogenesis, injection of effectors, and for secretion of the HrpZ1 harpin. J. Bacteriol. 188: 6060-6069.
  • Fereirra, A.O., C.R. Myers,J.S. Gordon, G.B. Martin, M. Vencato, Alan Collmer, M.D. Wehling, J.R. Alfano, G. Moreno-Hagelsieb, W.F. Lamboy, G. DeClerck, D.J. Schneider, and S.W. Cartinhour. 2006. Whole-genome expression profiling defines the HrpL regulon of Pseudomonas syringae pv. tomato DC3000, allows de novo reconstruction of the Hrp cis element, and identifies novel co-regulated genes. Mol. Plant Microbe Interact. 19: 1167-1179.
  • Vencato, M., F. Tian, J. R. Alfano, C. R. Buell, S. Cartinhour, G. A. DeClerck, D. S. Guttman, J. Stavrinides, V. Joardar, M. Lindeberg, P. A. Bronstein, J. W. Mansfield, C. R. Myers, A. Collmer, and D. J. Schneider. 2006. Bioinformatics-enabled identification of the HrpL regulon and type III secretion system effector proteins of Pseudomonas syringae pv. phaseolicola 1448A. Mol. Plant Microbe Interact. 19: 1193-1206.
  • Alvarez-Venegas, R., A. Al-Abdellat, J.R. Alfano, M. Guo, and Z. Avramova. 2006. Epigenetic Control of a Transcription Factor at the Cross Section of Two Antagonistic Pathways. Nuc. Acids Res. Submitted.
  • Wei, C.-F., B.H. Kvitko, R. Shimizu, E. Crabill, J.R. Alfano, N.-C. Lin, G.B. Martin, H.-C. Huang, and A. Collmer. 2006. A Pseudomonas syringae pv. tomato DC3000 mutant lacking the type III effector HopQ1-1 is able to cause disease in the model plant Nicotiana benthamiana. Plant J. Submitted.