Symbiosis articles from across Nature Portfolio

Diatoms are key marine primary producers and establish intricate partnerships with bacteria. Bacterium Loktanella enables diatoms to indirectly utilize glucose and maintains their photoautotrophic metabolism, indicating a common oceanic association.

Gassler et al. implant a free-living bacterium into fungal cells to study early steps in the establishment of an endosymbiosis. They observe vertical transmission of the bacteria despite initial host stress, with fungal defense responses attenuating over time, indicating a shift from antagonism toward commensalism.

Protist microbiomes are poorly understood. Here, the authors analysed single protist cells to profile their microbiomes and viromes showing that these tiny eukaryotes serve as environmental hubs for hidden bacterial symbionts and diverse giant viruses.

The evolutionary mechanisms leading to symbiont replacement in insects are not well understood. Zhou et al. show that genome degradation results in nested symbiosis and endosymbiont replacement in cicadas, offering insight into the endosymbiotic origins of cellular organelles.

Here, the authors present evidence that the gut microbiome alone, without changes in the host genome, can shape how animals respond to selection, identifying a bacterium and its metabolite that independently reduce mouse locomotion.

This Genome Watch article highlights recent discoveries on bacterial symbionts of predatory protists, and their evolutionary and functional integration into host biology.

In this Journal Club, Masaru Nobu revisits a paper that introduced the concept of syntrophy.

This study reports that that a gut fungus produces a secondary metabolite that protects against metabolic disease in mice.

A comparative genomic investigation of metabolism across the tree of life supports the hypothesis that syntrophy — metabolic exchange between symbiotic partners — had a key role in the evolution of eukaryotic cells.