Symbiosis articles from across Nature Portfolio

Symbiotic bacteria can have exceedingly small genomes. This study finds that ancient bacterial symbionts of planthoppers have repeatedly evolved the smallest known genomes, losing most biosynthetic functions, revealing how extreme genome reduction shapes life at the edge of cellular complexity.

Here, the authors show that gut bacteria promote reproduction in the oriental fruit fly by producing nicotinic acid that regulates energy metabolism and Lolal-dpp homeostasis.

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.

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.