Marine biofilms are multispecies microbial communities on surfaces that are crucial to the marine environment. They cause marine corrosion, biofouling, and transmission of marine pathogens and thus pose a great threat to public health and the maritime industry. To control marine biofilms, effective and environmentally friendly antibiofilm compounds are highly needed. Elasnin is a potent antibiofilm compound that exhibits high efficiency in inhibiting marine biofilms and biofouling, but its mode of action remains unclear. In the present study, multiomic analysis combined with quorum-sensing assays and in silico study revealed that elasnin acted as a signaling molecule in the microbial community. Elasnin promoted the growth of dominant species in the biofilm but deprived their ability of sensing and responding to environmental changes by disturbing their regulations of the two-component system, i.e., the ATP-binding cassette transport system and the bacterial secretion system. Consequently, biofilm maturation and subsequent biofouler settlement were inhibited. Elasnin also exhibited higher antibiofilm efficiency than dichlorooctylisothiazolinone and had low toxicity potential on the embryos and adults of marine medaka fish. Overall, this study provided molecular and ecological insights into elasnin's mode of action, highlighting its application potential in controlling marine biofilms and the feasibility and advantages of using signal molecules to develop eco-friendly technologies.
Keywords: ecotoxicity; elasnin; marine biofilms; quorum sensing; signaling molecules.