Natural products and morphogenic activity of γ-Proteobacteria associated with the marine hydroid polyp Hydractinia echinata

Abstract

Illumina 16S rRNA gene sequencing was used to profile the associated bacterial community of the marine hydroid Hydractinia echinata, a long-standing model system in developmental biology. 56 associated bacteria were isolated and evaluated for their antimicrobial activity. Three strains were selected for further in-depth chemical analysis leading to the identification of 17 natural products. Several γ-Proteobacteria were found to induce settlement of the motile larvae, but only six isolates induced the metamorphosis to the primary polyp stage within 24 h. Our study paves the way to better understand how bacterial partners contribute to protection, homeostasis and propagation of the hydroid polyp.

The colonial cnidarian Hydractinia

“…Current research on Hydractinia focuses on a number of topics, including embryonic development [14], neurogenesis [15,16], stem cells, germ cells, and regeneration [17][18][19][20], allorecognition [21], metabolism [22], immunity [23], and natural product chemistry [24]. Allorecognition refers to the ability to discriminate 'self ' from 'nonself ' within the same species, a phenomenon observed in most colonial cnidarians, but not in Hydra or Nematostella, the two most commonly used cnidarian model systems for molecular work.…”

Genetic examination of the marine bacterium Pseudoalteromonas luteoviolacea and effects of its metamorphosis‐inducing factors

“…Although many marine bacteria from diverse phyla have been shown to induce the metamorphosis of marine invertebrates (Unabia and Hadfield, 1999; Tran and Hadfield, 2011; Freckelton et al ., 2017; Guo et al ., 2017) only a handful have been studied to identify and characterize their metamorphosis‐inducing properties. One of these bacteria is Pseudoalteromonas luteoviolacea , which is a prodigious producer of bioactive compounds (Gauthier and Flatau, 1976; Laatsch and Pudleiner, 1989) and was shown to induce the metamorphosis of corals, sea urchins and tubeworms.…”

“…Hydroides has been used as a model organism to study bacteria‐stimulated metamorphosis because it is easily propagated in the laboratory (Hadfield et al ., 1994; Nedved and Hadfield, 2008) and its larvae settle and undergo metamorphosis in response to biofilms composed of a natural consortia (Huang and Hadfield, 2003) or single strains of bacteria (Unabia and Hadfield, 1999). The colonial hydroid, Hydractinia has been used as an important model to study development, immunology, reproduction (Frank et al ., 2001) and metamorphosis in response to Pseudoalteromonas species (Leitz and Wagner, 1993; Seipp et al ., 2007; Guo et al ., 2017, 2019). While the larvae of ecologically threatened animals, like stony corals that build coral reefs, are often difficult to obtain, Hydractinia serves as an accessible model cnidarian to investigate bacteria‐stimulated metamorphosis.…”

Molecular Network and Culture Media Variation Reveal a Complex Metabolic Profile in Pantoea cf. eucrina D2 Associated with an Acidified Marine Sponge

“…Compounds 2–4 were already isolated as mixture of enantiomers and an inseparable mixture together with their isoleucine congeners from Cobetia sp. isolated from the marine hydroid Hydractinia echinata [ 36 ].…”