Identification of virulence factors is a necessary first step to study the mechanisms and evolution of pathogenicity. We propose to compare the type III disease effector proteins from a phylogenetically diverse set of plant pathogenic Pseudomonads chosen to represent the most broad distribution of the species possible. P. syringae is an ideal model organism to study the distribution and evolution of type III effectors. Type III effectors interact with cellular host targets, and modulate host defense responses or metabolism in a manner conducive to pathogen proliferation. Most of the P. syringae effectors have not yet been characterized, and we remain naive as to the collective diversity of host cellular functions they manipulate. Although the functions of P. syringae effector proteins during disease remain poorly understood, they can often be monitored via their phenotypes following in planta expression of a given type III effector. Bacterial pathogens of both animals, such as Salmonella spp., Yersinia spp., Shigella spp. and pathogenic E. coli also rely on type III secretion systems for pathogenesis. Thus, our results will inform studies of these bacteria and their animal hosts, including humans. Because P. syringae is pathogenic on a variety of distantly related plant hosts, many of which can be genetically manipulated, our system has advantages over models of type III pathogenesis of animals, which generally focus only on strains pathogenic on phylogenetically related mammalian hosts. We have devised and implemented a high throughput Fluorescence Activated Cell Sorter (FACS) based experimental approach to capture all of the type III effectors from the genome of any given P. syringae isolate. We chose 13 P syringae isolates that are pathogens of an evolutionarily diverse set of host plants. We intend to sieve through these 13 genomes to describe their suites of type III effectors. We further intend to begin dissection of their effects on host cell biology, using the easily manipulated Arabidopsis plant as a model where appropriate. This proposal is highly interdisciplinary, drawing on methodologies and expertise in microbiology, bioinformatics and plant-pathogen interactions in conjunction with high throughput bacterial cell sorting using the FACS. Our work will broadly impact the understanding of a widely distributed pathogenicity mechanism that affects both human health and agriculture. Additionally, our work may have relevance in biodefense with respect to basic understanding of pathogenesis in bacteria that can potentially be weaponized.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM066025-04
Application #
7158585
Study Section
Genome Study Section (GNM)
Program Officer
Eckstrand, Irene A
Project Start
2004-01-01
Project End
2008-05-04
Budget Start
2007-01-01
Budget End
2008-05-04
Support Year
4
Fiscal Year
2007
Total Cost
$276,167
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Bartoli, Claudia; Berge, Odile; Monteil, Caroline L et al. (2014) The Pseudomonas viridiflava phylogroups in the P.?syringae species complex are characterized by genetic variability and phenotypic plasticity of pathogenicity-related traits. Environ Microbiol 16:2301-15
Sarris, Panagiotis F; Trantas, Emmanouil A; Baltrus, David A et al. (2013) Comparative genomics of multiple strains of Pseudomonas cannabina pv. alisalensis, a potential model pathogen of both monocots and dicots. PLoS One 8:e59366
Baltrus, David A; Nishimura, Marc T; Dougherty, Kevin M et al. (2012) The molecular basis of host specialization in bean pathovars of Pseudomonas syringae. Mol Plant Microbe Interact 25:877-88
Bonardi, Vera; Cherkis, Karen; Nishimura, Marc T et al. (2012) A new eye on NLR proteins: focused on clarity or diffused by complexity? Curr Opin Immunol 24:41-50
Belkhadir, Youssef; Jaillais, Yvon; Epple, Petra et al. (2012) Brassinosteroids modulate the efficiency of plant immune responses to microbe-associated molecular patterns. Proc Natl Acad Sci U S A 109:297-302
Chung, Eui-Hwan; da Cunha, Luis; Wu, Ai-Jiuan et al. (2011) Specific threonine phosphorylation of a host target by two unrelated type III effectors activates a host innate immune receptor in plants. Cell Host Microbe 9:125-36
Baltrus, David A; Nishimura, Marc T; Romanchuk, Artur et al. (2011) Dynamic evolution of pathogenicity revealed by sequencing and comparative genomics of 19 Pseudomonas syringae isolates. PLoS Pathog 7:e1002132
Bonardi, Vera; Tang, Saijun; Stallmann, Anna et al. (2011) Expanded functions for a family of plant intracellular immune receptors beyond specific recognition of pathogen effectors. Proc Natl Acad Sci U S A 108:16463-8
Jaillais, Yvon; Belkhadir, Youssef; Balsemao-Pires, Emilia et al. (2011) Extracellular leucine-rich repeats as a platform for receptor/coreceptor complex formation. Proc Natl Acad Sci U S A 108:8503-7
Arabidopsis Interactome Mapping Consortium (2011) Evidence for network evolution in an Arabidopsis interactome map. Science 333:601-7

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