Epigenetic biosensors for bacteriophage detection and phage receptor discrimination

David Olivenza (1) , Josep Casadesús (1) , Mireille Ansaldi (2)

1 Universidad de Sevilla / University of Sevilla
2 LCB - Laboratoire de chimie bactérienne

Environmental monitoring of bacteria using phage-based biosensors has been widely developed for many different species. However, there are only a few available methods to detect specific bacteriophages in raw environmental samples. In this work, we developed a simple and efficient assay to rapidly monitor the phage content of a given sample. The assay is based on the bistable expression of the Salmonella enterica opvAB operon. Under regular growth conditions, opvAB is only expressed by a small fraction of the bacterial sub-population. In the OpvAB ON subpopulation, synthesis of the OpvA and OpvB products shortens the O-antigen and confers resistance to phages that use LPS as a receptor. As a consequence, the OpvAB ON sub-population is selected in the presence of such phages. Using an opvAB::gfp fusion, we could monitor LPS-binding phages in various media, including raw water samples. To enlarge our phage-biosensor panoply, we also developed biosensors able to detect LPS, as well as protein-binding coliphages. Moreover, the combination of these tools allowed to identify the bacterial receptor triggering phage infection. The epigenetic opvAB::gfp biosensor thus comes in different flavours to detect a wide range of bacteriophages and identify the type of receptor they recognize.

Domains: Life Sciences [q-bio]

David Olivenza, Josep Casadesús, Mireille Ansaldi. Epigenetic biosensors for bacteriophage detection and phage receptor discrimination. Environmental Microbiology, 2020, 22 (8), pp.3126-3142. ⟨10.1111/1462-2920.15050⟩. ⟨hal-02995656⟩