Resistance to viruses, phytoplasmas and their vectors in the grapevine in Europe: A review

Control of grapevine virus and phytoplasma diseases is currently based on prophylactic measures and cultural practices. Certification programs aim to avoid the introduction of diseased grapevines into healthy vineyards, and cultural practices aim to reduce the populations of virus vectors to limit virus spread. These approaches however are of limited effectiveness. Additionally, there is no host resistance to viruses in grapevine identified so far. Genetic engineering provides new approaches to develop pathogen-resistant grapevines. Transgenic grapevines expressing virus-derived genes that can confer resistance have been obtained in several laboratories. The viral coat protein gene has been the most commonly used to engineer resistance. More recently, new approaches based on gene silencing, specifically triggering plant defence mechanisms, have opened new ways to engineer pathogen resistance in grapevines. The possibilities, benefits and advantages, but also the risks involved with the introduction of transgenic grapevines in the field, as well as their acceptability, are discussed in this review.