Fig. 1.

Swarming motility and colony morphology of V. parahaemolyticus phase variants. Three single colonies from each strain—LM5312 (opaR⁺), LM5674 (ΔopaR), LM6633 (opaR⁺), and LM4476 (?)—were inoculated with a toothpick onto an HI swarm agar and Congo red medium. The swarm plates were photographed after overnight growth at 30°C. Congo red plates were incubated overnight at 30°C and were allowed to develop for 1 week at room temperature before photography. LM5312, LM5674, and LM4476 are spontaneous phase variants of strain BB22; strain LM6633 was constructed by allelic exchange to repair the opaR locus of strain LM5674. The genetic basis for the translucent phenotype of strain LM4476 was unknown; hence the “?” for its genotype. In this work, we demonstrate that strain LM4476 carries a missense mutation, designated luxO*.