gene from two-component system is essential for caries pathogenicity in dual-species biofilms of and .

INTRODUCTION

This study elucidated the critical role of the gene in the () two-component signal (TCS) transduction system during cross-kingdom interactions with (). This gene governs the cariogenic potential of dual-species biofilms.

METHODS

Gene expression analysis of cocultured samples was performed. The survival rate during HO treatment in single and dual-species was assessed. Bacterial adhesion, extracellular polysaccharide (EPS) synthesis, acidic metabolite accumulation, and early adhesion of in dual-species biofilms were evaluated.

RESULTS

Compared with the wild-type () and complemented strains (liaS-comp), liaS- exhibited impaired acid tolerance due to downregulated comDE expression. The knockout mutant strain also presented reduced expression, leading to diminished glucosyltransferase (Gtf)-mediated bacterial adhesion, EPS synthesis, and acidic metabolite accumulation. Although alleviated oxidative stress by secreting superoxide dismutase, liaS- markedly compromised the intracellular reactive oxygen species (ROS) scavenging capacity and reduced the survival rate during HO treatment in single and dual-species. Furthermore, liaS- inactivation suppressed the early adhesion of in dual-species biofilms by reducing the synthesis of cyclic adenosine monophosphate (cAMP).

CONCLUSION

This work provides the first evidence that orchestrates a multidimensional phenotypic regulatory network that coordinately modulates biofilm architecture and metabolic activity. This activity ultimately attenuates cariogenicity , thus highlighting liaS as a pivotal virulence determinant in cross-kingdom infections and emphasizing its potential as a therapeutic target against dental caries.