Unveiling the Role of Diffusible Signal Factor-Family Quorum Sensing Signals in Regulating Behavior of Xanthomonas and Lysobacter

Diffusible signal factor (DSF) family signals represent a unique group of quorum sensing (QS) chemicals that modulate a wide range of behaviors for bacteria to adapt to different environments. However, whether DSF-mediated QS signaling acts as a public language to regulate the behavior of biocontrol and pathogenic bacteria remains unknown. In this study, we present groundbreaking evidence demonstrating that RpfF or RpfF could be a conserved DSF-family signal synthase in or . Interestingly, we found that both RpfF and RpfF have the ability to synthesize DSF and BDSF signaling molecules. DSF and BDSF positively regulate the biosynthesis of an antifungal factor (heat-stable antifungal factor, HSAF) in . Finally, we show that RpfF and RpfF have similar functions in regulating HSAF production in , as well as the virulence, synthesis of virulence factors, biofilm formation, and extracellular polysaccharide production in . These findings reveal a previously uncharacterized mechanism of DSF-mediated regulation in both biocontrol and pathogenic bacteria.