AUTHOR=Wienhausen Gerrit , Noriega-Ortega Beatriz E. , Niggemann Jutta , Dittmar Thorsten , Simon Meinhard 

TITLE=The Exometabolome of Two Model Strains of the Roseobacter Group: A Marketplace of Microbial Metabolites

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01985

DOI=10.3389/fmicb.2017.01985

ISSN=1664-302X

ABSTRACT=<p>Recent studies applying Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) showed that the exometabolome of marine bacteria is composed of a surprisingly high molecular diversity. To shed more light on how this diversity is generated we examined the exometabolome of two model strains of the <italic>Roseobacter</italic> group, <italic>Phaeobacter inhibens</italic> and <italic>Dinoroseobacter shibae</italic>, grown on glutamate, glucose, acetate or succinate by FT-ICR-MS. We detected 2,767 and 3,354 molecular formulas in the exometabolome of each strain and 67 and 84 matched genome-predicted metabolites of <italic>P. inhibens</italic> and <italic>D. shibae</italic>, respectively. The annotated compounds include late precursors of biosynthetic pathways of vitamins B<sub>1</sub>, B<sub>2</sub>, B<sub>5</sub>, B<sub>6</sub>, B<sub>7</sub>, B<sub>12</sub>, amino acids, quorum sensing-related compounds, indole acetic acid and methyl-(indole-3-yl) acetic acid. Several formulas were also found in phytoplankton blooms. To shed more light on the effects of some of the precursors we supplemented two B<sub>1</sub> prototrophic diatoms with the detected precursor of vitamin B<sub>1</sub> HET (4-methyl-5-(β-hydroxyethyl)thiazole) and HMP (4-amino-5-hydroxymethyl-2-methylpyrimidine) and found that their growth was stimulated. Our findings indicate that both strains and other bacteria excreting a similar wealth of metabolites may function as important helpers to auxotrophic and prototrophic marine microbes by supplying growth factors and biosynthetic precursors.</p>