Submitted to: Phycologia Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2003
Publication Date: 9/4/2003
Citation: WISE, M.L. MONOTERPENE BIOSYNTHESIS IN MARINE ALGAE. PHYCOLOGIA JOURNAL. 2003. 42(4):370-377. Interpretive Summary: Monoterpenes are ten carbon metabolites found in many herbs and spices and are readily recognized as the principle flavor and aroma components of, for example, spearmint, peppermint, lemon or culinary sage. Because of their value in the food, beverage and perfumery industry substantial research has provided a detailed understanding of the metabolic pathways and enzymes involved in their bioxsynthesis. Marine algae also produce monoterpenes, however they present certain chemical features suggesting metabolic pathways different from those seen in terrestrial plants. Marine monoterpenes also possess novel bioactivities, some of which portend their use as pharmaceuticals or agrichemicals. Unfortunately these compounds are exceedingly difficult to produce by synthetic chemical methods. Recent advances in the culture of a marine alga that produces these compounds as well as discoveries related to the enzymes involved suggests that biotechnical solutions to their production are highly feasible. This manuscript provides a review of the current literature regarding the biosynthesis of halogenated monoterpenes in macrophytic marine algae as it compares to terrestrial plants and will allow scientists a more focused approach to solving this largely unexplored metabolic pathway.
Technical Abstract: Marine algae produce a variety of secondary metabolites involved in chemical defense. Among these the monoterpenes present several highly unusual characteristics relative to their terrestrial counterparts. The monoterpenes produced by these marine organisms are nearly always halogenated and possess ring structures quite unlike those seen in monoterpenes originating from terrestrial plants. These chemical features belie novel biosynthetic pathways and mechanisms. Although limited in scope and number, field studies suggest that these compounds play a role in the chemical ecology of marine algae, similar to the more extensively studied terrestrial monoterpenes. This review examines the biogenetic pathways proposed for marine algal halogenated monoterpenes and compares these with the more thoroughly defined biosynthetic mechanisms involved in monoterpene production in terrestrial plants. A detailed characterization of monoterpene biosynthesis in cultured Ochtodes secundiramea (Rhodophyta) is also presented with implications for this system as a model to study the biosynthesis of these unusual metabolites and to evaluate the function of these secondary metabolites in marine chemical ecology.