The bacteria found on grapevines seem to come mostly from soil, a finding that could help researchers to understand how soil microbes influence the properties of wine made from the grapes.

Jack Gilbert at Argonne National Laboratory in Illinois and his colleagues took samples of soil and Merlot grapevines from five vineyards on Long Island, New York. They sequenced the bacterial genomes found in the soil and on the plants, and discovered that the bacterial communities on various plant parts were more similar to those in the soil around the roots than to each other. This suggests that the soil is a key bacterial reservoir for grapevines.

These grapevines seem to share a core microbial composition with those from California and from Bordeaux in France.

mBio 6, e02527–14 (2015)