CHARACTERIZING MEATBOLOMIC PATTERNS OF PROCHLOROCOCCUS MED4 ASSOCIATED WITH BLOOM AND MORTALITY IN MONO VS. CO-CULTURE

Marine microorganisms are major players in the biogeochemical cycle of our planet. As such, understanding how interactions between such microorganisms affect their physiology and metabolism of the interacting cells, is an essential field of research. In this study, we explore how the cell physiology and metabolome of a primary producer, Prochlorococcus MED4, change over different stages of batch culture, in mono-culture and in co-culture with a heterotrophic bacterium (Alteromonas macleodii HOT1A3). Our main analytical approach, untargeted metabolomics, enables the characterization of differentially expressed specialized metabolites by applying state-of-the-art mass spectrometry tools. So far, we have been able to characterize the changes in chemistry across the growth cycle of Prochlorococcus and associate unique masses to the phases of peak growth and culture decline. These metabolomic associations to population physiological state are supported by fluorescence measurements, cell counts and electron microscopy. Our vision is that such analysis will help identify the molecular mechanisms of microbial interactions, support predictive genome-scale models of cells interacting, and potentially provide novel biomarkers to enable the rapid identification and quantification of interactions between these important microorganisms in their natural marine environment.