P102: Molecular networking reveals species-specific patterns in the marine actinomycete genus Salinispora

Genome sequencing has revealed that actinomycetes contain many more biosynthetic pathways then would be predicted based on the numbers of secondary metabolites they produce.  These “silent” gene clusters may in fact be expressed but the products missed using traditional natural product discovery tools.  The generation of molecular networks based on MS-MS data provides a rapid and highly sensitive approach to visualize secondary metabolite profiles in extracts of cultured bacteria.  This technique facilitates strain comparison and can be used to prioritize strains for more detailed discovery efforts.  Here we have generated molecular networks for 35 Salinispora strains for which draft genome sequences are available.  Each strain was fermented in triplicate and the extracts analyzed by HR-MS-MS.  The networks were populated with standards to aid the identification process and can be used to delineate the three Salinispora species supporting prior observations of species-specific patterns of secondary metabolite production.   Unique nodes can be linked to the genome sequence data in an effort to identify candidate biosynthetic pathways and facilitate structure predictions.  Combining new fermentation approaches with molecular networking provides opportunities to improve the efficiency with which natural products are discovered.