Glycosyltransferases play a pivotal role in regulating biofilm formation and pathogenicity in Streptococcus suis

In bacteria, the glycosyltransferases play important roles in bacterial fitness and virulence. A prior transposon screen implicated glycosyltransferase Gtf-2 in the regulation of S. suis biofilm formation, but the biological function of Gtf-2 and how biofilm is modulated by Gtf-2 remains largely unclear. Here, we characterized the major components of S. suis biofilm matrix and further elucidated the its regulatory role in biofilm formation, which involved the regulation of S. suis extracellular matrix, c-di-AMP, cell surface properties, and bacterial energy metabolism. Additionally, we also revealed that Gtf-2 regulates the content and composition of capsular polysaccharide. Finally, the regulatory role of Gtf-2 in the virulence of S. suis was elucidated based on in vitro and in vivo infection models, and the loss of Gtf-2 function weakened the virulence of S. suis.