Fiat Lux: The Squid–Vibrio Association as a Model for Understanding Host–Microbe Associations

Abstract

The symbiosis between the Hawaiian bobtail squid Euprymna scolopes and the bioluminescent bacterium Vibrio fischeri offers an experimentally tractable model for understanding the role of beneficial bacteria on animal development and the mechanisms by which host and symbionts establish and maintain highly specific associations. The symbiont is transmitted from the environment each generation, and mechanisms must be in place to ensure specificity. Research over the years has revealed some of the “molecular dialogue” that occurs between the partners during and after colonization. Many of these interactions involve microbe-associated molecular patterns (MAMPs) and host pattern recognition receptors (PRRs) as well as components of the host’s innate immune system. The role of light production by the symbiont and light detection by the host is also critical to the association and has likely served as a driving force during the evolution of this symbiosis. Finally, the host harbors a second symbiosis, housing a consortium of bacteria in the female reproductive system. Euprymna scolopes therefore offers the unique opportunity to study both a binary and consortial symbiosis in the same host.