Description

Host-microbe interactions are pervasive, diverse, and strongly influential on a number of biological processes including development; however, the complexity of whole microbiomes makes understanding critical early developmental interactions at a mechanistic level challenging. `Hydroides elegans undergo metamorphosis when they come into contact with a diversity of bacteria in the wild, but aside from a single example; little is known about the molecular cues in such interactions that trigger Hydroides metamorphosis. Here, we set out to study a broad range of Gram-negative and positive bacteria that are known to trigger Hydroides metamorphosis; sending 37 strains representing a range of Gammaproteobacteria, Flavobacteria, Alphaproteobacteria, and Actinobacteria for 16S amplicon rRNA sequencing. We then queried the metamorphosis-inducing capacity of these bacteria via biofilm assays. To determine the nature of inductive cues used by diverse bacteria, we will use biochemical tests using 3 representative strains of Pseudoalteromonas luteoviolacea, Phaeobacter gallaeciensis, and Leisingera janus; which will allow us to indicate whether the inducible factor is protein-based or not. Evidence of a new metamorphosis induction pathway can be seen by the alphaproteobacteria, in which the inducible factor has a non-protein, heat-stable characteristic of itself. Diverse Roseobacter groups attribute metabolic functions that are linked to their material association with phytoplankton, corals, other eukaryotes, mutualists, probionts, and pathogens; the groups ability to induce Hydroides metamorphosis displays another effect on the eukaryotic life forms. Alphaproteobacteria make up approximately 25-28% of wild type biofilm that induce metamorphosis for Hydroides elegans. Discovering other inductive mechanisms from other bacteria can broaden our understanding of larval-bacterial interactions not just with Hydroides, but with other marine invertebrates who build many marine ecosystems such as corals and urchins. This work also has potential for broad biotechnological uses in understanding bacterial-eukaryotic communication. Because most interactions with bacteria are complex, to understand these complicated interactions future research should include genetic and activity-guided approaches when studying interactions between bacteria and their associated hosts.