Evolution of the bacterial organelle responsible for magnetotaxis

• Magnetosomes are prokaryotic organelles found in three phyla of Gram-negative bacteria.
• About 10 genes are essential for the production of magnetosomes.
• The formation of magnetite or greigite is controlled by genetic and environmental factors.
• The gene clusters determining the formation of magnetosomes are monophyletic.

There are few examples of protein- and lipid-bounded organelles in bacteria that are encoded by conserved gene clusters and lead to a specific function. The magnetosome chain represents one of these rare examples and is responsible for magnetotaxis in magnetotactic bacteria (MTB), a behavior thought to aid in finding their optimal growth conditions. The origin and evolution of the magnetotaxis is still a matter of debate. Recent breakthroughs in isolation, cultivation, single-cell separation, and whole-genome sequencing have generated abundant data that give new insights into the biodiversity and evolution of MTB.