Bacterial marginolactones lead to aggregation of algal cells into gloeocapsoids.

Marginolactones are natural substances produced by soil bacteria. Scientists have now observed an interesting aggregation of normally unicellular green algae Chlamydomonas reinhardtii caused by marginolactones.

The formation of multicellular organisms represents the origin of the development of animals and plants. But how did unicellular organisms become permanent multicellular living beings? One step closer to solving this riddle has been made by scientists from Jena and Leipzig.

The number of microorganisms that can be found in the soil is countless - microbes, fungi and unicellular algae live side by side in close proximity. Competition between the organisms is unavoidable, as habitat and food are limited. The life of these microorganisms is ruled by natural products, i.e. molecules, which are produced by bacteria and fungi. The importance of these molecules in the communication between organisms has been known for some time, but now the team around Axel Brakhage, Director of the Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute and Professor at the Friedrich Schiller University Jena, discovered that some of these natural products cause an uncommon aggregation of unicellular green algae. These natural products, called marginolactones, in high doses are deadly for the green algae. By forming an alliance, they can survive against these natural products. As soon as the concentration of marginolactones has reduced and the danger has passed, the unicellular green algae part ways again. The researchers suggest that the assembly of cells into these aggregations is an early stage of multicellularity.

Original Publication

Krespach MKC, Stroe MC, Flak M, Komor AJ, Nietzsche S, Sasso S, Hertweck C, Brakhage AA (2021) Bacterial marginolactones trigger formation of algal gloeocapsoids, protective aggregates on the verge of multicellularity. PNAS, https://doi.org/10.1073/pnas.2100892118.

See press release by Christine Vogler (Leibniz-HKI)