TY - JOUR
T1 - The Erwinia amylovora PhoPQ system is involved in resistance to antimicrobial peptide and suppresses gene expression of two novel type III secretion systems
AU - Nakka, Sridevi
AU - Qi, Mingsheng
AU - Zhao, Youfu
N1 - Funding Information:
This work was funded by the USDA National Institute of Food and Agriculture (NIFA) (Hatch project # Illu-802-317 ), USDA-NIFA-Agriculture and Food Research Initiative (AFRI) functional genomics project, and the Agricultural Experiment Station of Illinois.
PY - 2010/10/20
Y1 - 2010/10/20
N2 - The PhoPQ system is a pleiotropic two-component signal transduction system that controls many pathogenic properties in several mammalian and plant pathogens. Three different cues have been demonstrated to activate the PhoPQ system including a mild acidic pH, antimicrobial peptides, and low Mg2+. In this study, our results showed that phoPQ mutants were more resistant to strong acidic conditions (pH 4.5 or 5) than that of the wild-type (WT) strain, suggesting that this system in Erwinia amylovora may negatively regulate acid resistance gene expression. Furthermore, the PhoPQ system negatively regulated gene expression of two novel type III secretion systems in E. amylovora. These results are in contrast to those reported for the PhoPQ system in Salmonella and Xanthomonas, where it positively regulates type III secretion system and acid resistance. In addition, survival of phoPQ mutants was about 10-fold lower than that of WT when treated with cecropin A at pH 5.5, suggesting that the PhoPQ system renders the pathogen more resistant to cecropin A.
AB - The PhoPQ system is a pleiotropic two-component signal transduction system that controls many pathogenic properties in several mammalian and plant pathogens. Three different cues have been demonstrated to activate the PhoPQ system including a mild acidic pH, antimicrobial peptides, and low Mg2+. In this study, our results showed that phoPQ mutants were more resistant to strong acidic conditions (pH 4.5 or 5) than that of the wild-type (WT) strain, suggesting that this system in Erwinia amylovora may negatively regulate acid resistance gene expression. Furthermore, the PhoPQ system negatively regulated gene expression of two novel type III secretion systems in E. amylovora. These results are in contrast to those reported for the PhoPQ system in Salmonella and Xanthomonas, where it positively regulates type III secretion system and acid resistance. In addition, survival of phoPQ mutants was about 10-fold lower than that of WT when treated with cecropin A at pH 5.5, suggesting that the PhoPQ system renders the pathogen more resistant to cecropin A.
KW - Antimicrobial peptide
KW - Fire blight
KW - Two-component system
KW - Type III secretion
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U2 - 10.1016/j.micres.2009.11.013
DO - 10.1016/j.micres.2009.11.013
M3 - Article
C2 - 20116983
AN - SCOPUS:78049418323
SN - 0944-5013
VL - 165
SP - 665
EP - 673
JO - Microbiological Research
JF - Microbiological Research
IS - 8
ER -