[Seminar] "Magnetotaxis: How Microbes Use Earth's Magnetic Field to Navigate" by Dr. Caroline L. Monteil

Magnetoreception is the sense whereby organisms geolocate and navigate in response to the Earth's magnetic field lines. For decades, magnetotactic bacteria were the only known magnetoreceptive microorganisms. The magnetotactic behavior of these aquatic prokaryotes results from the biomineralization of magnetic crystals. The magnetic moment induced by these nanomagnets, together with the molecular mechanisms of oxygen sensing, constitutes a set of adaptations that allow these microorganisms to respond to fluctuations in the environmental redox potential and facilitate their vertical movement in aquatic habitats. Numerous observations have revealed their great genotypic, physiological, and morphological diversity, but their very strict metabolic requirements for oxygen and iron make them difficult to isolate and cultivate. Over the past decade, culture-independent approaches have helped overcome these limitations. New genome sequencing technologies and single-cell approaches have generated a massive amount of data, giving us a better picture of the evolution and genetic determinism underlying such a complex function. Magnetotaxis is no longer specific to bacteria: recent discoveries have demonstrated the existence of unicellular eukaryotes able to sense the geomagnetic field, and have revealed the variety of mechanisms and strategies involved in such sensing.

References:
Bolzoni R et al. Magnetoreception in a freshwater ciliate arises from endosymbiosis. Nat Commun 2026;17:3732. https://doi.org/10.1038/s41467-026-70462-8

Monteil CL, Vallenet D, Menguy N, Benzerara K, Barbe V, Fouteau S, Cruaud C, Floriani M, Viollier E, Adryanczyk G, Leonhardt N, Faivre D, Pignol D, López-García P, Weld RJ, Lefèvre CT (2019) Ectosymbiotic bacteria at the origin of magnetoreception in a marine protist. Nature Microbiology 4:1088-1095

Monteil CL, Lefevre CT (2019) Magnetoreception in microorganisms. Trends Microbiol. 28:266-275