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Many animals have multiple organs or tissues that are colonized by diverse microbiota. The female Hawaiian bobtail squid,Euprymna scolopes, has two organs with distinct symbiotic communities: the accessory nidamental gland (ANG) and the light organ (LO). The ANG hosts a bacterial consortium, whereas the LO has a binary relationship withVibriofischeri, housed in extracellular crypt spaces as part of the central core (CC). To understand how the host maintains distinct symbiotic communities, we used transcriptomics to identify immune-related genes that are uniquely and similarly expressed in the ANG and LO-CC compared to organs without a known microbiota. Genes such as peptidoglycan recognition proteins EsPGRP2 and EsPGRP3, cathepsin-Z, alkaline phosphatase, and acidic phospholipase exhibited significant upregulation in the symbiotic organs compared to other tissues like gills, skin, mantle, optic lobe, ovaries, and brain. Moreover, EsPGRP2 displayed distinct localization patterns within the ANG, inversely correlating with bacterial presence, whereas the protein was colocalized withV. fischeriin the LO-CC. Notably, 10 different galaxins (EsGal) were uniquely highly expressed in both the ANG and LO-CC, with EsGal1 messenger RNA predominantly localized to the LO-CC epithelium, while EsGal2 and EsGal3 were primarily found in the epithelia of ANG tubules. Furthermore, antimicrobial assays using partial peptides derived from EsGal1 and EsGal2 showed varying and distinct patterns of inhibitory activity for these peptides. In summary, our findings identify similar immune gene families expressed across functionally distinct symbiotic organs inE. scolopes, suggesting that common immunomodulatory factors may maintain distinct symbiotic niches in the host.
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Euprymna berryi as a comparative model host for Vibrio fischeri light organ symbiosis
ABSTRACT Functional studies of host-microbe interactions benefit from natural model systems that enable the exploration of molecular mechanisms at the host-microbe interface. BioluminescentVibrio fischericolonize the light organ of the Hawaiian bobtail squid,Euprymna scolopes, and this binary model has enabled advances in understanding host-microbe communication, colonization specificity,in vivobiofilms, intraspecific competition, and quorum sensing. The hummingbird bobtail squid,Euprymna berryi,can be generationally bred and maintained in lab settings and has had multiple genes deleted by CRISPR approaches. The prospect of expanding the utility of the light organ model system by producing multigenerational host lines led us to determine the extent to which theE. berryilight organ symbiosis parallels known processes inE. scolopes. However, the nature of theE. berryilight organ, including its microbial constituency and specificity for microbial partners, has not been examined. In this report, we isolated bacteria fromE. berryianimals and tank water. Assays of bacterial behaviors required in the host, as well as host responses to bacterial colonization, illustrate largely parallel phenotypes inE. berryiandE. scolopeshatchlings. This study revealsE. berryito be a valuable comparative model to complement studies inE. scolopes.IMPORTANCEMicrobiome studies have been substantially advanced by model systems that enable functional interrogation of the roles of the partners and the molecular communication between those partners. TheEuprymna scolopes-Vibrio fischerisystem has contributed foundational knowledge, revealing key roles for bacterial quorum sensing broadly and in animal hosts, for bacteria in stimulating animal development, for bacterial motility in accessing host sites, and forin vivobiofilm formation in development and specificity of an animal’s microbiome.Euprymna berryiis a second bobtail squid host, and one that has recently been shown to be robust to laboratory husbandry and amenable to gene knockout. This study identifiesE. berryias a strong symbiosis model host due to features that are conserved with those ofE. scolopes, which will enable the extension of functional studies in bobtail squid symbioses.
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- PAR ID:
- 10620643
- Editor(s):
- Rudi, Knut
- Publisher / Repository:
- American Society for Microbiology
- Date Published:
- Journal Name:
- Applied and Environmental Microbiology
- ISSN:
- 0099-2240
- Page Range / eLocation ID:
- e0000125
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1128/aem.00001-25
