Bacterial transcriptional response to picoeukaryote Micromonas commoda

Marine biogeochemical cycles are built on interactions between surface ocean microbes, particularly those connecting phytoplankton primary producers to heterotrophic bacteria. However, direct influences of bacteria on phytoplankton physiology are poorly known. In this study, three marine bacteria (Ruegeria pomeroyi DSS-3, Stenotrophomonas sp. SKA14, and Polaribacter dokdonensis MED152) were co-cultured with green alga Micromonas commoda, and the phytoplankter's transcriptome was studied by RNASeq. The presence of each bacterium invoked transcriptomic remodeling by M. commoda after 8 h in co-culture. Some aspects of the algal transcriptomic response were conserved across all three bacteria, while others were restricted to a single bacterium. M. commoda had both rapid and extensive responses to heterotrophic bacteria.