Single-cell bacterial transcription measurements reveal the importance of dimethylsulfoniopropionate (DMSP) hotspots in ocean sulfur cycling

Nat Commun. 2020 Apr 23;11(1):1942. doi: 10.1038/s41467-020-15693-z.


Dimethylsulfoniopropionate (DMSP) is a pivotal compound in marine biogeochemical cycles and a key chemical currency in microbial interactions. Marine bacteria transform DMSP via two competing pathways with considerably different biogeochemical implications: demethylation channels sulfur into the microbial food web, whereas cleavage releases sulfur into the atmosphere. Here, we present single-cell measurements of the expression of these two pathways using engineered fluorescent reporter strains of Ruegeria pomeroyi DSS-3, and find that external DMSP concentration dictates the relative expression of the two pathways. DMSP induces an upregulation of both pathways, but only at high concentrations (>1 μM for demethylation; >35 nM for cleavage), characteristic of microscale hotspots such as the vicinity of phytoplankton cells. Co-incubations between DMSP-producing microalgae and bacteria revealed an increase in cleavage pathway expression close to the microalgae's surface. These results indicate that bacterial utilization of microscale DMSP hotspots is an important determinant of the fate of sulfur in the ocean.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Gene Expression Regulation, Bacterial*
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Metabolic Networks and Pathways / genetics
  • Microalgae / metabolism
  • Microbial Interactions
  • Phytoplankton / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Rhodobacteraceae / genetics
  • Rhodobacteraceae / metabolism
  • Seawater / chemistry
  • Seawater / microbiology*
  • Single-Cell Analysis
  • Sulfonium Compounds / analysis
  • Sulfonium Compounds / metabolism*
  • Sulfur / analysis
  • Sulfur / metabolism*
  • Transcription, Genetic


  • Bacterial Proteins
  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • Sulfonium Compounds
  • Sulfur
  • dimethylpropiothetin