The variation in grape color is due to the genes responsible for the synthesis of red pigments (anthocyanins.) Through these variations, the varieties Pinot blanc and Pinot gris arose from Pinot noir.
Pinot noir is a red wine grape variety of the species Vitis vinifera. Pinot gris is a Pinot color variant, and Pinot blanc is a further mutation and can either naturally arise from or give rise to Pinot gris or Pinot noir. Pinot wines a generally lighter in style. They are at or around 12 percent alcohol by volume. Because of the thinness of the skins, Pinot Noir wines are lighter in color, body and tannins.
While the vine stocks used in viticulture, for any given variety, appear identical there are variations. Spontaneous genetic events can lead to differences between individual plants. To look at this further, scientists have been studying the molecular mechanisms that underpin the change of graper color.
For this research, a collection of 33 clones of Pinot noir, Pinot gris and Pinot blanc were examined. This study revealed that large-scale exchanges between homologous chromosomes, can sometimes shut down the genes that induce the biosynthesis of anthocyanins – the red color.
At times these cellular mutations propagate to form a distinct cell layer. This leads to chimeric plants. This explains how Pinot gris arose from Pinot noir. Here, a Pinot noir skin surrounds internal cells that have mutated to Pinot blanc. From this, Pinot blanc can sometimes emerge from Pinot gris as a result of different cellular rearrangements that spread the mutations throughout the plant.
The research is important because understanding the berry color can shed light on the driving forces for the genetic drift of clones and the evolution of the grapevine genetic make-up. This knowledge can help to foster specific types of grapes for wine growing.
The study was performed at the INRA (National Institute for Agricultural Research) Colmar, France. The findings have been published in the journal PLOS Genetics. The research is headed “Chromosome Replacement and Deletion Lead to Clonal Polymorphism of Berry Color in Grapevine.”
In related news, researchers have studied the microbial composition of a wine grapevine. The examination unearthed the fact that the microbes found in grapes, on leaves and flowers are derived from the microbes found in the plant’s roots.
