Acne bacteria spotted in grapevines
The bacterium which causes acne in humans has been found in Italian grapevines.
Proprionibacterium acnes - P. acnes - is a bacterium associated with human skin and is responsible, to the anguish of many a fresh face, for acne or 'zits'.
Published this week in the journal Molecular Biology and Evolution, Dr Andrea Campisano from the Edmund Mach Foundation, Research and Innovation Centre in Italy, reports a new type of P. acnes infecting a plant host.
This represents a unique example of a human pathogen crossing from a person to a crop plant.
The discovery was made when the team performed a genetic survey of the grapevine, Vitis vinifera, to identify which micro-organisms were living inside the plant.
Fifty-four of the sixty plants tested were found to contain DNA similar to the P. acnes bacteria. Looking down the microscope, the bacteria could be seen colonising the bark and even living inside cells in some parts of the plant.
To make the move from living on human skin to plant tissues, P. acnes must have undergone significant changes to adapt to its new environment. The bacterium has been named 'P. acnes type Zappae', or P. Zappae for short. This is partly after the Italian word for a garden hoe, 'zappa', and also in homage to the eccentric composer Frank Zappa due to its 'unexpected and unconventional habitat'.
Genetic comparisons with its closest relatives support a human origin for P. Zappae and suggest it adapted to life on the vine about 7,000 years ago, coinciding with the time when humans began growing grapes.
The researchers speculate that people manipulating plants led to the transfer of the bacteria. So it seems hugging a tree can spread more than just love.
The genetic analysis shows there are however differences between the human and grapevine strains. P. Zappae has lost the function of a critical gene called recA, which is essential for DNA repair. Instead it now relies on the grapevine to replace the missing gene.
The presence of the bacteria doesn't appear to affect the plants. "The plants that have the bacteria are perfectly healthy... we don't know if it is beneficial to the plant... but probably we will put some effort in this direction to understand if it can be used to improve plant health," explains Dr Andrea Campisano.
Acne bacteria found in grapevines