Development of a genetic system for Marinobacter adhaerens HP15 involved in marine aggregate formation by interacting with diatom cells

► Bacteria-diatom interactions lead to aggregate formation substantial for marine carbon dioxide fixation. ► A genetic system was developed for Marinobacter adhaerens inducing diatom aggregate formation. ► Transformation efficiencies, mutagenesis methods, and reporter gene expression were established for M. adhaerens. ► Optimized genetic tools may be applicable for other Marinobacter species. ► Study reveals useful tools for gene knock-out and expression analyses to gain mechanistic understanding of micro-scale interactions underlying ocean-scale processes.