Final answer:
The genes encoding quorum-sensing proteins in Vibrio fischeri are luxR and luxI. LuxR is the receptor protein, while LuxI produces signalling molecules for quorum sensing.
Step-by-step explanation:
The genes in Vibrio fischeri which encode for the quorum-sensing proteins are luxR and luxI. The luxR gene encodes for a protein that acts as a receptor, which can detect the presence of signalling molecules. On the other hand, the luxI gene encodes for an enzyme that is responsible for the production of these signalling molecules, known as autoinducers. Together, these proteins facilitate the regulation of gene expression in response to changes in cell population density, a process known as quorum sensing.