Open AccessThe phytopathogen Dickeya dadantii 3937 cpxR locus gene participates in the regulation of virulence and the global c‐di‐GMP network
Author(s) -
Jiang Daqing,
Zeng Quan,
Banerjee Biswarup,
Lin Haiping,
Srok John,
Yu Manda,
Yang ChingHong
Publication year - 2022
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.13219
Subject(s) - biology , mutant , virulence , type three secretion system , gene , genetics , microbiology and biotechnology , wild type , regulation of gene expression , lac operon , gene expression
Bacteria use signal transduction systems to sense and respond to their external environment. The two‐component system CpxA/CpxR senses misfolded envelope protein stress and responds by up‐regulating envelope protein factors and down‐regulating virulence factors in several animal pathogens. Dickeya dadantii is a phytopathogen equipped with a type III secretion system (T3SS) for manipulating the host immune response. We found that deletion of cpxR enhanced the expression of the T3SS marker gene hrpA in a designated T3SS‐inducing minimal medium (MM). In the ∆ cpxR mutant, multiple T3SS and c‐di‐GMP regulators were also up‐regulated. Subsequent analysis revealed that deletion of the phosphodiesterase gene egcpB in ∆ cpxR abolished the enhanced T3SS expression. This suggested that CpxR suppresses EGcpB levels, causing low T3SS expression in MM. Furthermore, we found that the ∆ cpxR mutant displayed low c‐di‐GMP phenotypes in biofilm formation and swimming. Increased production of cellular c‐di‐GMP by in trans expression of the diguanylate cyclase gene gcpA was negated in the ∆ cpxR mutant. Here, we propose that CpxA/CpxR regulates T3SS expression by manipulating the c‐di‐GMP network, in turn modifying the multiple physiological activities involved in the response to environmental stresses in D. dadantii .