image: Luminous symbionts (red) induce edema-associated gene expression (green) in adjacent host epithelia (nuclei, blue). view more
Credit: Silvia Moriano-Gutierrez
Researchers report that luminescent bacterial symbionts alter gene expression in their squid hosts. Animal microbiomes can affect tissues and organs anatomically distant from those with which they directly associate. However, the mechanisms underlying these effects remain unknown. Using the symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the luminous bacterial symbiont, Vibrio fischeri, Margaret McFall-Ngai and colleagues compared gene expression in the light organ, where the bacteria reside, as well as in the eye and gill, in the presence and absence of symbionts, in juvenile and adult animals and at different stages of the day-night cycle. Gene expression levels in both juveniles and adults differed in all three organs between symbiont-free and symbiont-colonized animals, and each organ had a unique set of differentially expressed genes. For certain genes in the eye and gill, the effect of symbiosis on expression varied with the time of day, with maximal effect in the early evening when the host is active. When colonized by a mutant symbiont unable to produce light, fewer genes in the light organ responded, and all of the typically responsive genes in the eye did not respond to the mutant symbionts. According to the authors, the results suggest that colonization of the squid light organ by V. fischeri causes system-wide changes in gene expression, some of which are driven by bioluminescence.
Article #18-19897: "Critical symbiont signals drive both local and systemic changes in diel and developmental host gene expression," by Silvia Moriano-Gutierrez et al.
MEDIA CONTACT: Margaret McFall-Ngai, University of Hawaii at Manoa, Honolulu, HI; tel: 808-956-8838, 608-332-7028; e-mail: mcfallng@hawaii.edu
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Journal
Proceedings of the National Academy of Sciences