Beneficial, Harmful Effects of Introgression Between Wild and Domesticated European Grapes

In a new study appearing in the Proceedings of the National Academy of Sciences, researchers from the State Key Laboratory of Tropical Crop Breeding in Shenzhen, China and elsewhere look at introgression between domesticated grapes, Vitis vinifera ssp. Vinifera, and their European wild relatives, V. vinifera ssp. sylvestris. Domesticated grapevines spread to Europe around 3,000 years ago, and while previous studies had revealed genomic signals of introgression from wild to cultivated grapes in Europe, the time, mode, genomic pattern, and biological effects of these introgression events have not been investigated, the authors write. By studying resequencing data from 345 samples from a range of wild and cultivated grapes from different areas and conducting machine learning-based genetic analyses, they found evidence of a single grapevine domestication event. This event was then followed by continuous gene flow between European wild grapes and cultivated grapes, particularly wine grapes, during the past nearly 2,000 years. Gene pathways associated with the synthesis of aromatic compounds were enriched in regions that were both selected and introgressed, suggesting EU wild grapes were an important resource for improving the flavor of cultivated grapes. However, introgression also increased the frequency of heterozygous but harmful SNPs and structural variants. "In general, our study of beneficial and harmful effects of introgression is critical for genomic breeding of grapevine to take advantage of wild resources," the authors write.