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Grazing-activated chemical defence in a unicellular marine alga

Wolfe, GV and Steinke, M and Kirst, GO (1997) 'Grazing-activated chemical defence in a unicellular marine alga.' Nature, 387 (6636). 894 - 897. ISSN 0028-0836

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Marine plankton use a variety of defences against predators, some of which affect trophic structure and biogeochemistry. We have previously shown that, during grazing by the protozoan Oxyrrhis marina on the alga Emiliania huxleyi, dimethylsulphoniopropionate (DMSP) from the prey is converted to dimethyl sulphide (DMS) when lysis of ingested prey cells initiates mixing of algal DMSP and the enzyme DMSP lyase. Such a mechanism is similar to macrophyte defence reactions. Here we show that this reaction deters protozoan herbivores, presumably through the production of highly concentrated acrylate, which has antimicrobial activity. Protozoan predators differ in their ability to ingest and survive on prey with high-activity DMSP lyase, but all grazers preferentially select strains with low enzyme activity when offered prey mixtures. This defence system involves investment in a chemical precursor, DMSP, which is not self-toxic and has other useful metabolic functions. We believe this the first report of grazing-activated chemical defence in unicellular microorganisms.

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science and Health > Life Sciences, School of
Depositing User: Michael Steinke
Date Deposited: 25 Mar 2013 13:22
Last Modified: 14 Aug 2019 10:16

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