Spatial and Temporal Resolution of Cyanobacterial Bloom Chemistry Reveals an Open-Ocean Trichodesmium thiebautii as a Talented Producer of Specialized Metabolites

While the ecological role that Trichodesmium sp.
play in nitrogen fixation has been widely studied, little information
is available on potential specialized metabolites that are associated
with blooms and standing stock Trichodesmium colonies.
While a collection of biological material from a T.
thiebautii bloom event from North Padre Island, Texas,
in 2014 indicated that this species was a prolific producer of chlorinated
specialized metabolites, additional spatial and temporal resolution
was needed. We have completed these metabolite comparison studies,
detailed in the current report, utilizing LC-MS/MS-based molecular
networking to visualize and annotate the specialized metabolite composition
of these Trichodesmium blooms and colonies in the
Gulf of Mexico (GoM) and other waters. Our results showed that T. thiebautii blooms and colonies found in the GoM
have a remarkably consistent specialized metabolome. Additionally,
we isolated and characterized one new macrocyclic compound from T. thiebautii, trichothilone A (1),
which was also detected in three independent cultures of T. erythraeum. Genome mining identified genes predicted
to synthesize certain functional groups in the T. thiebautii metabolites. These results provoke intriguing questions of how these
specialized metabolites affect Trichodesmium ecophysiology,
symbioses with marine invertebrates, and niche development in the
global oligotrophic ocean.