The GlrKR two-component system modulates virulence, environmental stress responses, and p-coumaric acid sensitivity in Cronobacter sakazakii

Cronobacter sakazakii is an opportunistic foodborne pathogen with remarkable resilience to environmental stressors, posing severe risks in powdered infant formula. Here, we identify the GlrKR two-component system (TCS) as a master regulator that integrates environmental sensing with virulence control. Genetic deletion of either the sensor kinase ( glrK ) or the response regulator ( glrR ) markedly attenuates bacterial motility, epithelial cell adherence, and virulence in a neonatal rat model. GlrK is essential for acid and oxidative stress resistance, whereas both GlrK and GlrR suppress desiccation tolerance, revealing a regulatory trade-off between environmental persistence and host invasion. Quantitative proteomics and site-specific mutagenesis uncover enhanced deamidation of OmpA at N101 in Δ glrR as a mechanistic basis for impaired adherence. Additionally, GlrKR modulates sensitivity to p -coumaric acid, a plant-derived antimicrobial, via transcriptional control of the efflux pump TolC. These findings establish GlrKR as a central node linking environmental adaptation, antimicrobial defense, and host-pathogen interaction in C. sakazakii , offering a promising target for next-generation food safety interventions. • GlrKR is essential for C. sakazakii resistance to acid, oxidative, and desiccation stress. • glrR deletion impairs adherence and motility via OmpA deamidation. • GlrKR-deficient strains are hypersensitive to p -coumaric acid due to TolC loss. • IbpB mediates GlrKR-dependent desiccation tolerance.