The delicate vanilla begins to reveal its secrets

Scientists have already identified more than 80% of the genome of the vanillaan essential step in developing more robust varieties of this delicate, disease-prone plant.

the pods of Vanilla Planifolia they contain a sticky blackish nectar that serves to give a recognizable perfume to the kitchen, in the whole world.

But this species, which represents more than 95% of the production of the essence of vanillin on the planet, has a serious problem, which affects its price: its genetic diversity is very low and therefore it is vulnerable to a fearsome disease, the fusariumwhich also affects other plants, such as potatoes or bananas.

Achieving new, more resistant varieties requires “a long time, from seven to eight years, grain by grain”explained the geneticist Carine Charronco-author of a study published in Plants Communication.

Until now, researchers only had a third of the genome sequence of Vanilla planifolia, which made it impossible to locate the genes that favor the crossing of varieties.

In 2017, a French research consortium began sequencing the rest of the Vanilla planifolia genome on the island of The meetingwhere the largest collection of vanilla in the world is located.

The plant, which belongs to the orchid family, has a very particular characteristic.

Almost a third of its genome is concentrated in the nucleus of plant cells, which makes it difficult to locate the remaining two thirds using classical sequencing methods.

“We have managed to partially overcome this problem through research in the nuclear tissues of the plant” that contain all DNA distributed on a regular basis, explained Quentin Pietdoctoral student at the University of La Réunion and main author of the study.

With this catalog of more than 59,000 genes, available on an online platform, researchers will be able to accelerate variety improvement programs.

“We will be able to find out more quickly if a cross between plant varieties has a gene that we are looking for, in order to continue with the selection process”Explain Carine Charronresponsible for the vanilla collection of a French scientific body, Cirad, with more than 500 varieties.

The first objective is to achieve a plant that is resistant to fusarium. “It is a chronic disease, a fungus that eats the roots and that greatly affects Vanilla Planifolia”explained Michel GrisoniCIRAD researcher in Madagascar.

80% of the world’s vanilla production is concentrated on this island in the Indian Ocean, far ahead of Indonesia, Mexico and La Reunion.

Fusarium wilt is a persistent fungus, contaminating the soil in Madagascar for at least a century and a half. The illness “forces the grower to colonize new land”adds the researcher.

This expert assures that climate change is also harming plantations, with higher temperatures in Mexico, which interrupt the reproductive cycle of the plant.

Thus “It is necessary to develop varieties that are better adapted to extreme conditions, and that are better resistant to diseases”.

This will in turn result in the aromatic diversity of the vanilla pod, the ovary of the flower that, after being manually pollinated, “only open for 24 hours”.