Biodiversity 3 min

How grapevine downy mildew invaded our vineyards: a look back at its voyage from North America

PRESS RELEASE - Plasmopara viticola, the pathogen responsible for grapevine downy mildew, causes destructive epidemics that can result in major losses for winegrowers. Although the biological determinants and mode of reproduction of the disease are well understood, we know almost nothing about its invasion history. How did this pathogen of North American origin come to invade the world? INRAE scientists have been working in collaboration with Université Paris-Saclay and CNRS to understand the process underlying this spread. Published on 25 March in Current Biology, their findings provide us with some keys to the mystery. A clearer understanding of its history, and hence its evolution, will offer a lever to control this parasite which is the reason for most fungicide treatments applied in vineyards.

Published on 26 March 2021

illustration How grapevine downy mildew invaded our vineyards: a look back at its voyage from North America
© INRAE - François Delmotte

There are several vine species, but also several species of the pathogen that cause grapevine downy mildew; each of the latter adapts to its host, thus complicating our understanding of its history and how it arrived in Europe. Downy mildew was first detected in France in 1878, but did one or several species form the bridgehead for its the invasion of Europe?


Tracking downy mildew in Europe

The scientists adopted a multidisciplinary approach to answer these questions, and discovered that the first contamination of European vines occurred 150 years ago and involved a single species of mildew, that which infected the wild vine Vitis aestivalis. The team then tracked it back in order to understand how it managed to infect French vineyards.  Their study suggests that the pathogen was introduced via wild American vines that were imported in order to control of powdery mildew and phylloxera1. Because France was the first country to be affected by phylloxera, it intensified varietal innovation by incorporating disease resistance from American wild vines in cultivated vines (V. vinifera). These cultivated European vines then served as the source for the introduction of the disease into vineyards throughout the world.

Starting in the 19th century, France was taken as the model for the modern vineyards that have developed worldwide and thus exported its hybrids and phylloxera-resistant rootstocks, and notably European varieties from the best known regions at that time (Cabernet, Merlot, Chardonnay, Syrah, etc.). It is therefore international trade that acted as a vector for the spread of downy mildew.

This scientific study offers new insights on grapevine downy mildew and notably its spread throughout the world. It highlights the importance of regulating international trade in plant materials in order to prevent other mildew species from being introduced into our vineyards.



Fontaine et al., 2021, Current Biology 31, 1–12 May 24, 2021 ª 2021 Elsevier Inc.

1 pest that affects commercial vineyards worldwide and which originated from eastern North America.


Learn more

Climate change and risks

First grapevine rootstock genome finally sequenced

PRESS RELEASE - INRA researchers, together with colleagues from the Institute of Vine & Wine Science (ISVV) of the University of Bordeaux, have published the first genome sequence of a grapevine rootstock. Their research culminated with the assembly and annotation of the American native Vitis riparia Gloire de Montpellier genome. Up until now, only the European variety Vitis vinifera had been sequenced. In most vineyards around the world, grapevine is grown grafted onto rootstocks, since they offer resistance to soil-dwelling pests—like Phylloxera—and improve its capacity to adapt to different environments. This high-quality sequence opens new avenues to identify genes of agronomic interest that do not exist in the European variety (disease and pest resistance, environmental adaptation) including some specific to roots. This sequence will also allow experts to envision new approaches to improve grapevines and their cultivation, which are highly threatened by pathogens, constrained growing conditions, and climate change. The results were published in the journal Scientific Data on 19 July 2019.

12 December 2019


Stella Césari: a ‘budding’ scientist recognised for her work in plant science

Stella Césari, a young researcher at the Biology and Genetics of Plant-Pathogen Interactions (BGPI) joint research unit in Montpellier, France, has won the 2017 New Phytologist Tansley Medal for Excellence in Plant Science. The scientific journal New Phytologist awarded Stella this medal on 8 March 2018 in recognition of her work studying intracellular plant immune receptors and her contribution to the discovery of "integrated decoy” domains in plant immune receptors.

04 February 2020

Food, Global Health

Control of mosquito-borne diseases: discovery of a new genetic element in the Wolbachia bacterium

PRESS RELEASE - Researchers from INRAE, Cirad, CEA, the University of Montpellier, and Chicago and Vanderbilt Universities in the United States have developed an innovative method for analysing the genome of the Wolbachia bacterium. This endosymbiotic bacterium infects more than 70% of insects and is capable of influencing insect transmission of pathogens such as dengue or Zika virus. By sequencing and studying all DNA present in the ovaries of Culex pipiens mosquitoes, the researchers identified for the first time a novel mobile genetic element in this bacterium. This discovery opens up new research avenues to better understand interactions between the Wolbachia bacterium and its host mosquito, as well as its role in pathogen transmission. This research, published in Nature Communications, provides opportunities for the biological control of insect-borne pathogens, a major public health challenge.

01 April 2020