TY - JOUR
T1 - Systems level analysis of two-component signal transduction systems in Erwinia amylovora
T2 - Role in virulence, regulation of amylovoran biosynthesis and swarming motility
AU - Zhao, Youfu
AU - Wang, Dongping
AU - Nakka, Sridevi
AU - Sundin, George W.
AU - Korban, Schuyler S.
N1 - Funding Information:
We are grateful to Dr. Barry Wanner at Purdue University, Dr. S. Kushner at University of Georgia, and Dr. R. Valdivia at Duke University for providing the pKD46, pKD13 and pKD3, pWSK29 and pFPV25 plasmids, respectively. We would like to thank Dr. Virginia Stockwell at Oregon State University for providing part of the immature pear fruits used in this experiment. We are also grateful to Dr. Steve Beer at the Cornell University and the Sanger Institute for the genome sequence of E. amylovora strain Ea273. This work was supported by the USDA Cooperative State Research, Education and Extension Service (Hatch project # Illu-802-317) and the Agricultural Experiment Stations of Illinois and Michigan.
PY - 2009/5/26
Y1 - 2009/5/26
N2 - Background: Two-component signal transduction systems (TCSTs), consisting of a histidine kinase (HK) and a response regulator (RR), represent a major paradigm for signal transduction in prokaryotes. TCSTs play critical roles in sensing and responding to environmental conditions, and in bacterial pathogenesis. Most TCSTs in Erwinia amylovora have either not been identified or have not yet been studied. Results: We used a systems approach to identify TCST and related signaltransduction genes in the genome of E. amylovora. Comparative genomic analysis of TCSTs indicated that E. amylovora TCSTs were closely related to those of Erwinia tasmaniensis, a saprophytic enterobacterium isolated from apple flowers, and to other enterobacteria. Forty-six TCST genes in E. amylovora including 17 sensor kinases, three hybrid kinases, 20 DNA- or ligand-binding RRs, four RRs with enzymatic output domain (EAL-GGDEF proteins), and two kinases were characterized in this study. A systematic TCST gene-knockout experiment was conducted, generating a total of 59 single-, double-, and triple-mutants. Virulence assays revealed that five of these mutants were non-pathogenic on immature pear fruits. Results from phenotypic characterization and gene expression experiments indicated that several groups of TCST systems in E. amylovora control amylovoran biosynthesis, one of two major virulence factors in E. amylovora. Both negative and positive regulators of amylovoran biosynthesis were identified, indicating a complex network may control this important feature of pathogenesis. Positive (non-motile, EnvZ/OmpR), negative (hypermotile, GrrS/GrrA), and intermediate regulators for swarming motility in E. amylovora were also identified. Conclusion: Our results demonstrated that TCSTs in E. amylovora played major roles in virulence on immature pear fruit and in regulating amylovoran biosynthesis and swarming motility. This suggested presence of regulatory networks governing expression of critical virulence genes in E. amylovora.
AB - Background: Two-component signal transduction systems (TCSTs), consisting of a histidine kinase (HK) and a response regulator (RR), represent a major paradigm for signal transduction in prokaryotes. TCSTs play critical roles in sensing and responding to environmental conditions, and in bacterial pathogenesis. Most TCSTs in Erwinia amylovora have either not been identified or have not yet been studied. Results: We used a systems approach to identify TCST and related signaltransduction genes in the genome of E. amylovora. Comparative genomic analysis of TCSTs indicated that E. amylovora TCSTs were closely related to those of Erwinia tasmaniensis, a saprophytic enterobacterium isolated from apple flowers, and to other enterobacteria. Forty-six TCST genes in E. amylovora including 17 sensor kinases, three hybrid kinases, 20 DNA- or ligand-binding RRs, four RRs with enzymatic output domain (EAL-GGDEF proteins), and two kinases were characterized in this study. A systematic TCST gene-knockout experiment was conducted, generating a total of 59 single-, double-, and triple-mutants. Virulence assays revealed that five of these mutants were non-pathogenic on immature pear fruits. Results from phenotypic characterization and gene expression experiments indicated that several groups of TCST systems in E. amylovora control amylovoran biosynthesis, one of two major virulence factors in E. amylovora. Both negative and positive regulators of amylovoran biosynthesis were identified, indicating a complex network may control this important feature of pathogenesis. Positive (non-motile, EnvZ/OmpR), negative (hypermotile, GrrS/GrrA), and intermediate regulators for swarming motility in E. amylovora were also identified. Conclusion: Our results demonstrated that TCSTs in E. amylovora played major roles in virulence on immature pear fruit and in regulating amylovoran biosynthesis and swarming motility. This suggested presence of regulatory networks governing expression of critical virulence genes in E. amylovora.
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U2 - 10.1186/1471-2164-10-245
DO - 10.1186/1471-2164-10-245
M3 - Article
C2 - 19470164
AN - SCOPUS:67650136711
SN - 1471-2164
VL - 10
JO - BMC genomics
JF - BMC genomics
M1 - 245
ER -