Similar but different: Characterization of <i>dddD</i> gene–mediated DMSP metabolism among coral-associated <i>Endozoicomonas</i>

Abstract

<i>Endozoicomonas</i> are often predominant bacteria and prominently important in coral health. Their role in dimethylsulfoniopropionate (DMSP) degradation has been a subject of discussion for over a decade. A previous study found that <i>Endozoicomonas</i> degraded DMSP through the <i>dddD</i> pathway. This process releases dimethyl sulfide, which is vital for corals coping with thermal stress. However, little is known about the related gene regulation and metabolic abilities of DMSP metabolism in <i>Endozoicomonadaceae</i>. In this study, we isolated a novel <i>Endozoicomonas</i> DMSP degrader and observed a distinct DMSP metabolic trend in two phylogenetically close <i>dddD</i>-harboring <i>Endozoicomonas</i> species, confirmed genetically by comparative transcriptomic profiling and visualization of the change of DMSP stable isotopes in bacterial cells using nanoscale secondary ion spectrometry. Furthermore, we found that DMSP cleavage enzymes are ubiquitous in coral <i>Endozoicomonas</i> with a preference for having DddD lyase. We speculate that harboring DMSP degrading genes enables <i>Endozoicomonas</i> to successfully colonize various coral species across the globe.