Antagonistic bacteria disrupt calcium homeostasis and immobilize algal cells
Aiyar P, Schaeme D, García-Altares M, Carrasco Flores D, Dathe H, Hertweck C, Sasso S, Mittag M2017Antagonistic bacteria disrupt calcium homeostasis and immobilize algal cells Nat Commun
Abstract
Photosynthetic unicellular organisms, known as microalgae, are key contributors to carbon fixation on Earth. Their biotic interactions with other microbes shape aquatic microbial communities and influence the global photosynthetic capacity. So far, limited information is available on molecular factors that govern these interactions. We show that the bacterium Pseudomonas protegens strongly inhibits the growth and alters the morphology of the biflagellated green alga Chlamydomonas reinhardtii. This antagonistic effect is decreased in a bacterial mutant lacking orfamides, demonstrating that these secreted cyclic lipopeptides play an important role in the algal-bacterial interaction. Using an aequorin Ca2+-reporter assay, we show that orfamide A triggers an increase in cytosolic Ca2+ in C. reinhardtii and causes deflagellation of algal cells. These effects of orfamide A, which are specific to the algal class of Chlorophyceae and appear to target a Ca2+ channel in the plasma membrane, represent a novel biological activity for cyclic lipopeptides.
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Doctoral researchers
Dr. rer. nat. Prasad Aiyar
Molecular dissection of early signaling response in the green alga Chlamydomonas reinhardtii under the influence of biotic and abiotic factors
Friedrich Schiller University
Matthias Schleiden Institute - General Botany
David Carrasco Flores
Establishing a model system for studying abiotic and biotic interactions of a flagellate green microalga in the marine environment
Friedrich Schiller University
Matthias Schleiden Institute - General Botany
Daniel Schaeme
Identification of Novel Secondary Metabolites with Roles in Interactions Between Chlamydomonas reinhardtii and Other Microorganisms