The grape, consumed as fruit or in wine, comes from the domesticated vine Vitis vinifera, a descendant of the wild vine (Vitis sylvestris). For several years, the domestic vine has been examined from all angles, mobilizing disciplines from genetics to physiology to physics. But a question remained in the scientific world: how to explain that the domestic vine is hermaphroditic when its wild ancestor is not? For the first time, scientists from INRAE, CNRS and the Université Claude Bernard Lyon 1 were able to sequence the genome of wild grapes. This sequencing, using innovative techniques, made it possible to read this ancestral genome and identify genes that allow the vine to change sex. Their work appeared September 7 in the journal Genome biology.

Flowering plants are often hermaphroditic, but in about 6% of species the sexes are separated with an evolution of male and female plants. A situation similar to that of many animals. These sex-separated species, called dioecious by botanists, are over-represented among cultivated plants (approximately 20%). We observed cases in which the domesticated plant and its wild ancestor are dioecious (eg, date palm, asparagus, persimmon) and cases in which domestication was accompanied by a reversion to hermaphroditism (eg, vine, papaya, strawberry). ). This change in the sexual system has been a key factor in the domestication of the vine and the production of grapes. In fact, if the domestic vine were not hermaphroditic, then it would be necessary to plant males to pollinate the females to produce grapes. This situation would imply the presence of vine plants that would not bear fruit, the males, and the risks of imperfect fertilization of the females, giving incomplete clusters. But then what changes took place in the sexual system of the vine during its domestication?

To answer this question, researchers from INRAE, CNRS and the Université Claude Bernard Lyon 1 sequenced and analyzed the DNA of wild grapes, a novelty in plant biology. Thanks to innovative techniques, several candidate genes involved in sexual determinism have been identified in wild grapes. One of these genes, involved in the abortion of female organs in male flowers, has been naturally altered in house grapes. This gene represents an excellent candidate to explain the reversion to hermaphroditism in domestic grapevines. This work represents a great advance in the understanding of the domestication process of the vine, and the methodology used can be used to elucidate changes in the sexual systems in other cultivated plants of dioecious origin.