Mou, X., M. A. Moran, R. Stepanauskas, J. M. González, and R. E. Hodson. 2005. Culture-independent identification of bacterioplankton involved in DMSP transformations by flow cytometric cell sorting and subsequent molecular analyses. Appl. Environ. Microbiol. 71:1405-1416.

Marine bacterioplankton transform dimethylsulfoniopropionate (DMSP) into the biogeochemically important and climatically active gas dimethylsulfide (DMS). In order to identify specific bacterial taxa mediating DMSP processing in a natural marine ecosystem, we amended water samples from a southeastern US salt marsh with 20 μM DMSP and tracked community shifts with flow cytometry coupled to 16S rRNA gene analyses. In two out of four seasons studied, DMSP amendments induced the formation of distinct bacterioplankton populations with elevated nucleic acid (NA) content within 24 h, indicative of cells actively utilizing DMSP. The 16S rRNA genes of the cells with and without elevated NA content were analyzed following cell sorting and PCR amplification using sequencing and terminal restriction fragment length polymorphism approaches. Compared to cells in the control FCM populations, bacteria with elevated NA content in the presence of DMSP were relatively enriched in taxa related to Loktanella, Oceanicola and Sulfitobacter, (Roseobacter lineage, α-Proteobacteria), Caulobacter (α-Proteobacteria), and Curvibacter and Xenophilus (β-Proteobacteria) in the May-02 sample; and to Ketogulonicigenium (Roseobacter lineage, α-Proteobacteria) and Microbulbifer (γ-Proteobacteria) in the Sept-02 sample. Our study suggests that a diverse group of bacterioplankton participates in the metabolism of DMSP in coastal marine systems and their relative importance varies temporally.