Controlled motility in the cyanobacterium Trichodesmium regulates aggregate architecture

• Published in: Science (American Association for the Advancement of Science) Vol. 380; no. 6647; pp. 830 - 835
• Main Authors: Pfreundt, Ulrike, Słomka, Jonasz, Schneider, Giulia, Sengupta, Anupam, Carrara, Francesco, Fernandez, Vicente, Ackermann, Martin, Stocker, Roman
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 26-05-2023
• Subjects: Aggregates; Cyanobacteria; Filaments; Mathematical models; Models, Biological; Nitrogen Fixation; Nitrogenation; Oceans and Seas; Positive feedback; Reactive oxygen species; Trichodesmium; Trichodesmium - cytology; Trichodesmium - physiology
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.adf2753

The ocean's nitrogen is largely fixed by cyanobacteria, including
, which forms aggregates comprising hundreds of filaments arranged in organized architectures. Aggregates often form upon exposure to stress and have ecological and biophysical characteristics that differ from those of single filaments. Here, we report that
aggregates can rapidly modulate their shape, responding within minutes to changes in environmental conditions. Combining video microscopy and mathematical modeling, we discovered that this reorganization is mediated by "smart reversals" wherein gliding filaments reverse when their overlap with other filaments diminishes. By regulating smart reversals, filaments control aggregate architecture without central coordination. We propose that the modulation of gliding motility at the single-filament level is a determinant of
's aggregation behavior and ultimately of its biogeochemical role in the ocean.