YqeH contributes to avian pathogenic Escherichia coli pathogenicity by regulating motility, biofilm formation, and virulence

Abstract

Avian pathogenic Escherichia coli (APEC) is a pathotype of extraintestinal pathogenic E. coli and one of the most serious infectious diseases of poultry. It not only causes great economic losses to the poultry industry, but also poses a serious threat to public health worldwide. Here, we examined the role of YqeH, a transcriptional regulator located at E. coli type III secretion system 2 (ETT2), in APEC pathogenesis. To investigate the effects of YqeH on APEC phenotype and virulence, we constructed a yqeH deletion mutant (APEC40-ΔyqeH) and a complemented strain (APEC40-CΔyqeH) of APEC40. Compared with the wild type (WT), the motility and biofilm formation of APEC40-ΔyqeH were significantly reduced. The yqeH mutant was highly attenuated in a chick infection model compared with WT, and showed severe defects in its adherence to and invasion of chicken embryo fibroblast DF-1 cells. However, the mechanisms underlying these phenomena were unclear. Therefore, we analyzed the transcriptional effects of the yqeH deletion to clarify the regulatory mechanisms of YqeH, and the role of YqeH in APEC virulence. The deletion of yqeH downregulated the transcript levels of several flagellum-, biofilm-, and virulence-related genes. Our results demonstrate that YqeH is involved in APEC pathogenesis, and the reduced virulence of APEC40-ΔyqeH may be related to its reduced motility and biofilm formation.

EspE3 plays a role in the pathogenicity of avian pathogenic Escherichia coli

“…The E. coli strains utilized for this study were AE81 and the AE81 mutant strain with yqeH deletion (Δ yqeH ) [ 9 ], ygeG deletion (Δ ygeG ) [ 12 ], and ETT2 cluster deletion (ΔETT2) [ 13 ], all constructed and stored by the Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control (Table 1 ). The espE3 gene deletion strain (Δ espE3 ) and complementary strain (C espE3 ) in AE81 were constructed in this study.…”

“…In this study, we used ygeG [ 12 ] and yqeH [ 9 ] coded in the ETT2 cluster, which was shown to affect the virulence of APEC in our previous studies, as a representative to test whether the ETT2 genes affect the transcription of espE3 . The effects of ETT2, ygeG and yqeH on the transcription level of the espE3 gene were detected by fluorescence quantitative PCR as described previously [ 15 ].…”

“…The transcription of espE3 in each strain at different growth stages (OD 600 = 0.8, 1.3, 1.7) was detected. ΔETT2, Δy qeH and Δ ygeG of AE81 were generated using the standard λ Red recombinase system with the pKD46 and pKD3 template plasmids and the pCP20 FLP recombinase plasmid [ 9 , 12 , 13 ]. AE81, ΔETT2, Δy qeH and Δ ygeG were cultured at 37 °C, and total RNA was extracted using the Bacteria RNA Extraction Kit (Vazyme, Qixia District, Nanjing City, Jiangsu Province, China) according to the manufacturer’s instructions.…”

“…E.coli type III secretion system 2 (ETT2), encoded in the genome of APEC [ 5 , 6 ], participates in the regulation of a variety of pathogenic phenotypes and in the pathogenicity characterization of APEC, ETT2 has been described as an important bacterial virulence gene cluster. APEC-ETT2 encodes a variety of transcriptional regulators, such as YqeI [ 7 ], EivF [ 8 ], YgeH [ 9 ] and EtrA [ 10 ], that regulate the pathogenicity of APEC. At the same time, APEC-ETT2 also encodes ATPase EivC [ 11 ] and the molecular chaperone YgeG [ 12 ] to contribute to pathogenicity.…”

Characteristics, pathogenic mechanism, zoonotic potential, drug resistance, and prevention of avian pathogenic Escherichia coli (APEC)

“…However, the degenerative form of ETT2 may contribute to reducing the virulence and serum survival activity in bacteria ( Wang et al, 2016a ). Multiple components of ETT2 are involved in the pathogenicity of APEC ( Wang et al, 2016a ; Fu et al, 2021 ; Tu et al, 2021 ; Li et al, 2022 ; Xue et al, 2022 ; Yin et al, 2022 ). Our research shows that the transcriptional regulator DctR can regulate the expression of ETT2 and affect the virulence and pathogenicity of APEC ( Zhang et al, 2021 ).…”