%0 Journal Article %A Jani, Sneha %A Seely, Andrew L. %A Peabody V, George L. %A Jayaraman, Arul %A Manson, Michael D. %T Chemotaxis to self-generated AI-2 promotes biofilm formation in Escherichia coli %D 2017 %J Microbiology, %V 163 %N 12 %P 1778-1790 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.000567 %K lsr operon %K AI-2 chemotaxis %K self-aggregation %K biofilm %I Microbiology Society, %X Responses to the interspecies quorum-sensing signal autoinducer-2 (AI-2) regulate the patterns of gene expression that promote biofilm development. Escherichia coli also senses AI-2 as a chemoattractant, a response that requires the periplasmic AI-2-binding protein LsrB and the chemoreceptor Tsr. Here, we confirm, as previously observed, that under static conditions highly motile E. coli cells self-aggregate and form surface-adherent structures more readily than cells lacking LsrB and Tsr, or than ΔluxS cells unable to produce AI-2. This difference is observed both at 37 and 30 °C. Cells deleted for the genes encoding the lsrACDBFG operon repressor (ΔlsrR), or the AI-2 kinase (ΔlsrK), or an AI-2 uptake channel protein (ΔlsrC), or an AI-2 metabolism enzyme (ΔlsrG) are also defective in biofilm formation. The Δtsr and ΔlsrB cells are totally defective in AI-2 chemotaxis, whereas the other mutants show normal or near-normal chemotaxis to external gradients of AI-2. These data demonstrate that chemotaxis to external AI-2 is necessary but not sufficient to induce the full range of density-dependent behaviours that are required for optimal biofilm formation. We also demonstrate that, compared to other binding-protein-dependent chemotaxis systems in E. coli, low levels (on the order of ~250 molecules of periplasmic LsrB per wild-type cell and as low as ~50 molecules per cell in some mutants) are adequate for a strong chemotaxis response to external gradients of AI-2. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000567