Now Wine Grapevines Get Acne, Too

The bacteria that made your high school days a living nightmare also terrorizes the plants that help you cope with that early emotional scarring: Italian scientists say a close-relative of the bacteria that causes acne has jumped from humans to wine grapes.

It’s one of the first times bacteria that infects humans has made the jump to a plant, but it’s probably not going to create mutant varietals like Zitfandel or Greasling anytime soon. The bacteria—dubbed P. Zappae after guitar virtuoso Frank Zappa for some reason (the researchers were listening to a lot of Zappa at the time of the discovery)—has existed in grapevines for about 7,000 years. Humans have suffered from acne for roughly 15,000 years.

“We have found this unusual bug in plants when it should have been living on human skin,” said Andrea Campisano, of Italy’s Edmund Mach Foundation Research and Innovation Center. “The fact that human bacteria can become so specifically symbiotic with plants is itself a discovery.”

The discovery was published in Molecular Biology and Evolution.

Campisano thinks that P. Acne jumped from humans to grapevines because of the winemaking industry.

“We speculate that is transferred with the beginning of human agricultural activities and grapevine handling, cutting, and grafting,” he said.

Though P. Zappa is closely related to P. Acne—it evolved from the bacteria that causes pimples—the bacteria poses no threat to grapevines and also poses no threat to humans. Campisano was unable to get the bacteria to grow in the laboratory—it appears to need the grapevine in order to survive at all.

“The effect of the bacterium on plants is not known, but we know that the bug has undergone profound genomic modifications to better adapt to the plant,” he said. “Also, it's definitely not a pathogen to the plant. Grapevines that carry it are perfectly healthy.”

Though the bacteria doesn’t seem to have any obviously important impact on a grapevine, the discovery is still notable, because scientists have long thought that humans might be able to pass microbes to plants, but, until now, there was very little documentation supporting the theory. Last month, researchers discovered a virus that had made the jump from plants to honeybees.

“It was speculated, but never demonstrated, that human bugs could adapt so well to live inside plant cells,” Campisano said. “This is an exceptional symbiosis not only because it entails humans and a culturally important plant such as a grapevine, but also because it demonstrates that animals and plants have exchanged and probably keep exchanging microbes.”