Novel approaches for viral disease management

Abstract

Due to the severity of viral epidemics, the limited efficacy and cost of disease management strategies, and lack of recognized sources of resistance in Vitis spp., as well as the increasing societal demand for sustainable and environmentally safe viticulture practices, there is a great need to develop grapevines that are resistant to viruses. Genetic transformation and the antiviral pathways of RNA interference have been extensively explored to develop virus-resistant grapevines. These technologies have been validated against several viruses primarily in herbaceous experimental hosts. Their application to grapevines is more limited with only a restricted number of field trials conducted so far in naturally infected vineyard settings in France and in the USA. These field trials essentially focused on resistance to grapevine fanleaf virus with encouraging preliminary results. Recent advances in our understanding of RNA interference as a plant immune mechanism against viruses and of the structure and genetic variability of virus populations are providing new opportunities to facilitate the engineering of virus-derived transgene constructs for durable resistance. Other antiviral strategies based on nanobody interference, vector control, and host genome editing are explored; these will eventually pave the way for a paradigm shift in viral disease management in grapevine. Today, the development of virus-resistant grapevines for practical disease management remains at an early genesis; unfortunately, roadblocks preventing an evolution toward release are legion, especially in regions where research and industry priorities are disconnected, and the flow of communication between researchers and industry groups is sporadic. Building bridges between the research community and potential end users, while establishing a transparent and sustained dialogue, is essential for a timely deployment of highly needed virus-resistant grapevines in the future.