The CpxAR Two-Component System Contributes to Growth, Stress Resistance, and Virulence of Actinobacillus pleuropneumoniae by Upregulating wecA Transcription

Abstract

Actinobacillus pleuropneumoniae is the pathogen of porcine contagious pleuropneumonia. In A. pleuropneumoniae, the CpxAR two-component system is essential for fitness and growth. The O-antigen protrudes from the outer membrane to the exterior of the cell, and the outer membrane serves as a barrier that helps the bacteria to survive in harsh environments. WecA, a undecaprenyl phosphate GlcNAc-1-phosphate transferase, is involved in O-antigen repeating unit biosynthesis. In this study, we investigated the role of CpxAR in the expression of wecA in A. pleuropneumoniae. Our results revealed that CpxR positively regulates wecA expression by directly binding to the putative promoter region of wecA. Wild-type, cpxAR, wecA, and complemented strains were investigated under serum, oxidative, and osmotic stresses. The cpxAR and wecA strains were more susceptible to these stresses than the wild-type, but the complemented strains showed phenotypes similar to those of the wild-type. Mice infected with the cpxAR and wecA strains exhibited lower mortality and bacterial loads in the lung than those infected with the wild-type or complemented strains. This study reveals that the CpxAR two-component system contributes to A. pleuropneumoniae growth, stress resistance, and virulence, by upregulating expression of wecA. Our findings provide new insight into the pathogenesis of A. pleuropneumoniae.

Identification of a Genetically Linked but Functionally Independent Two-Component System Important for Cell Division of the Rice Pathogen Burkholderia glumae

“…The virulence-factor biosynthesis and motility of B. glumae are dependent on QS ( Kim et al, 2004 , 2007 ). As well as QS, we are interested in TCSs in B. glumae BGR1 because they coordinate and regulate the expression of genes critical for adaptation to stress, survival, fitness in the host, and virulence ( Uhl and Miller, 1996 ; Perraud et al, 1998 ; Groisman, 2001 ; Bronner et al, 2004 ; Loui et al, 2009 ; Freeman et al, 2013 ; Yan et al, 2020 ). For instance, CpxAR of Actinobacillus pleuropneumoniae ( Yan et al, 2020 ), ArcAB of Escherichia coli ( Loui et al, 2009 ), and KdpDE ( Freeman et al, 2013 ) and PhoPQ ( Groisman, 2001 ) in a variety of bacterial taxa reportedly promote growth, fitness, and survival in the host.…”

Genomic Analysis of Serratia plymuthica MBSA-MJ1: A Plant Growth Promoting Rhizobacteria That Improves Water Stress Tolerance in Greenhouse Ornamentals

“…The envZ / ompR TCS plays a vital role in mediating signal transduction in response to osmotic stress and is involved in the uptake of K + ions ( Gerken and Misra, 2010 ; Yuan et al, 2011 ). Additionally, the cpxAR TCS is essential for rhizospheric fitness and growth by helping the bacteria to survive under harsh environments such as severe water stress ( Yan et al, 2020 ). MBSA-MJ1 also encodes for mzrA which not only acts as a regulator of the envZ / ompR TCS without altering its ability to receive and respond to environmental signals, but also links envZ / ompR to cpxAR to further support cellular envelope stress responses ( Gerken et al, 2009 ).…”

Genome-Wide Identification of Genes Involved in Acid Stress Resistance of Salmonella Derby

“…The adhesion and invasion rate of the Δ cpxR strain was significantly decreased compared to the WT ( Figure 5 C,D). Previous studies also showed that TCS CpxAR could directly sense acidic conditions to regulate the expression of fabAB in E. coli [ 41 ], and contributes to stress resistance and virulence in Actinobacillus pleuropeumoniae [ 51 ]. Moreover, the CpxAR-mediated envelope stress response plays a crucial role in the gut infection of S .…”