Work

Genome-reduced Aridivitia evolved predation to thrive in Earth’s oligotrophic depths

Year: 2026

Type: article

Abstract: Deep soils represent one of Earth’s largest yet most enigmatic microbial habitats, where survival strategies under extreme oligotrophy remain poorly understood. Here, we report the Aridivitia group, a globally distributed bacterial lineage enriched in oligotrophic soils and thriving down to 22 m depth across sites in the United States and China. Despite its genome reduction (average size ~2.9 Mb), Aridivitia exhibits high metabolic flexibility in utilizing diverse carbon and energy sources. Cellular, genomic, and metatranscriptomic evidence, including small cell and genome sizes, host-associated metabolism, and the active expression of attachment- and attack-associated surface structures such as Tad pili and pore-forming toxins, indicate a predatory lifestyle in Aridivitia. Ancestral genome reconstruction reveals that Aridivitia originated as free-living mixotrophs, but subsequently lost the ability to fix carbon as they evolved a predatory lifestyle. Collectively, Aridivitia exemplifies a unique evolutionary strategy that reconciles genome reduction with functional versatility, expanding our understanding of microbial adaptation and evolution at the energetic limits of life.

Source: Nature Communications

DOI: 10.1038/s41467-026-78342-x