Anders Ljungberg/Flickr (CC BY 2.0)
Around 7,000 years ago, a bacterium that lives on humans and causes acne leaped to a very different host: domesticated grapevines. Since then, an essential DNA-repair gene in the microbe, Propionibacterium acnes, has mutated and no longer functions. Without the gene, the microbe is unable to function on its own and appears to rely on the grapevine for these DNA repairs. This is the first report of such a symbiosis between a plant and a microbe that’s typically associated with animals, says microbiologist Andrea Campisano of Italy’s Edmund Mach Foundation.