Project description:Halogenases, and the halogenated organic molecules that they furnish are thought to be highly specialized secondary metabolites produced in only modest amounts. The widespread production of bromoform by marine macroalgae contradicts this paradigm wherein up to 8% dry weight of the red seaweed Asparagopsis taxiformis comprises of this brominated natural product. In this study, using paired transcriptomic and proteomic workflows, we determine that the bromoform-producing halogenase in A. taxiformis, Mbb1, is one of the most abundant proteins in the seaweed tissue with proteomic abundance rivaling that of enzymes involved in photosynthesis and carbon fixation. The proteomic abundance of Mbb1 is matched by the high transcript abundance of the mbb1 gene. Production of Mbb1 was found independent of the ecological source of the seaweed tissue with comparable transcript abundances detected between stress-free laboratory-cultivated, and appropriately stressed field-collected tissue samples. Taken together, these findings allow us to posit that bromoform production is not a stress-response or self-defense mechanism for A. taxiformis and instead fulfills a core metabolic role in marine macroalgal physiology.
