Siderophores from Neighboring Organisms Promote the Growth of Uncultured Bacteria

SummaryThe majority of bacterial species do not grow on synthetic media. Many non-growers require growth factors from other bacteria, but the nature of these compounds is largely unknown. We show here that previously uncultured isolates from marine sediment biofilm grow on a Petri dish in the presence of cultured organisms from the same environment. The growth factors produced by one cultured helper strain were identified as new acyl-desferrioxamine siderophores. A panel of previously uncultured isolates exhibited a range of siderophore promiscuity for growth promotion. This siderophore-based approach has enabled the culturing of organisms only distantly related to previously cultured microbes. The lack of growth in the laboratory for many strains from this habitat stems from an inability to autonomously produce siderophores, and the resulting chemical dependence on other microorganisms regulates community establishment in the environment.

Graphical AbstractFigure optionsDownload high-quality image (158 K)Download as PowerPoint slideHighlights
► Some cultured bacteria can help previously uncultured bacteria grow in the laboratory
► The model helper bacterium produced at least five new acyl-desferrioxamine siderophores
► Many uncultured bacteria are chemically dependent on siderophores from other microbes
► Addition of siderophores enabled the isolation of rare bacteria