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

Abstract

Summary Pseudoalteromonas luteoviolacea is a globally distributed marine bacterium that stimulates the metamorphosis of marine animal larvae, an important bacteria–animal interaction that can promote the recruitment of animals to benthic ecosystems. Recently, different P . luteoviolacea isolates have been shown to produce two stimulatory factors that can induce tubeworm and coral metamorphosis; Metamorphosis‐Associated Contractile structures (MACs) and tetrabromopyrrole (TBP) respectively. However, it remains unclear what proportion of P . luteoviolacea isolates possess the genes encoding MACs, and what phenotypic effect MACs and TBP have on other larval species. Here, we show that 9 of 19 sequenced P . luteoviolacea genomes genetically encode both MACs and TBP. While P . luteoviolacea biofilms producing MACs stimulate the metamorphosis of the tubeworm Hydroides elegans , TBP biosynthesis genes had no effect under the conditions tested. Although MACs are lethal to larvae of the cnidarian Hydractinia symbiologicarpus , P . luteoviolacea mutants unable to produce MACs are capable of stimulating metamorphosis. Our findings reveal a hidden complexity of interactions between a single bacterial species, the factors it produces and two species of larvae belonging to different phyla.

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