Researchers map North American wild grape pangenome

North America’s wild grapes are now less mysterious after an international team of researchers led by the University of California, Davis, decoded and cataloged the genetic diversity of nine species of this valuable wine crop.

The research, published in the journal Genome biologyreveals critical traits that could accelerate grape breeding efforts, particularly to address challenges such as climate change, saline environments and drought.

“This research marks an important step in understanding grapevine genetics,” said Dario Cantù, lead author of the journal article and professor in the Department of Viticulture and Enology. “It lays the foundation for future advances in grape breeding by identifying key genes responsible for important traits.”

The research team developed and used cutting-edge technology to construct a complete pangenome, which is a complete genetic model of wild grape species.

This so-called super-pangenome of nine species allowed the team to map genetic diversity, identify similarities or differences between them, and identify specific traits that breeders might want to incorporate. First author Noé Cochetel, a postdoctoral researcher in Cantù’s lab, performed the analyzes and played a central role in the project.

This is the first North American wild grape pangenome to be mapped and cataloged, Cantù said.

“This offers enormous potential to advance sustainable grape growing, especially in regions facing water scarcity issues,” said Cantù, a plant biologist who also holds the Louis P. Martini Endowed Chair. “This pangenome will enable further genetic exploration of other vital adaptive traits critical to industry resilience, such as drought tolerance, heat resistance, and defense against Pierce’s disease.”

Caused by a strain of the bacteria Xylella fastidiosa, Pierce’s disease kills vines by blocking their water-conducting vessels.

Benefits and harms of wild grapes

North American grapes are known for their disease resistance and adaptability, but they are not favored for taste and wine quality. European vines like Chardonnay and Cabernet Sauvignon are less resistant to disease but are known for producing high quality wines.

North American species have a wide geographic range. As a result, they have evolved to resist diverse climatic, soil and pathogenic conditions, encompassing a broad spectrum of genetic diversity.

This is why almost all wine grapes produced worldwide come from European vines grafted onto North American rootstocks.

Ability to select traits

The detailed pangenome will allow breeders to selectively incorporate desired traits from wild grapes, such as salt tolerance, while avoiding less desirable traits.

“Salt tolerance is a crucial trait for rootstocks,” Cantù noted. “The identification of these characters at the genetic level constitutes a major advance for grape breeding.”