Plant-virus interactions under stress

Plant adaptation to drought and virus epidemiology (APSEVIR)

Agricultural production and the functioning of ecosystems are frequently constrained by episodes of drought and rising temperatures, the frequency and duration of which are expected to increase under the influence of climate change, particularly in Mediterranean and tropical areas and therefore in Languedoc-Roussillon. Research in agronomy should make it possible to propose changes in agricultural practices and sustainable management of ecosystems in a context of limited water resources. Interactions between plants, their pathogens, symbionts, vectors and the abiotic environment are still not sufficiently integrated into this research. To date, about 900 phytoviruses have been described, infecting about 70% of plants and causing major losses in productivity. In addition to the negative impact of viruses on their host plants, an unexpected but converging aspect of these viruses emerges from the literature. In some cases, virus infection could be beneficial by improving plant tolerance to abiotic stresses, such as water deficit or high temperature. These results could be related to the high reactivity of phytoviruses to perceive and react (in terms of transmission efficiency and virulence) in response to a disturbed external environment (drought, heat). The aim of the APSEVIR project ("Adaptation des plantes à la sècheresse et épidémiologie virale") is therefore to better understand plant-virus interactions under drought conditions and, in the long term, to consider the use of the diversity of these interactions to deal with productivity losses in current and future environments. The project will attempt to answer two questions: 1) Does viral infection improve plant tolerance to abiotic stresses and can this characteristic be used? 2) What are the consequences of drought and high temperature on the epidemiology of phytoviruses. The idea that a directed viral inoculation ("tolerance vaccine") could help plants cope with abiotic stresses is emerging and could lead to innovative applications. The strategy to answer these questions will be: 1) to identify the genetic basis of plant responses to viral infections under drought and high temperature conditions; 2) to analyse the relationships between virulence, viral transmission efficiency, and tolerance to drought and high temperature; and 3) to model the dynamics of plant-virus interactions and therefore of epidemiological parameters (virulence, transmission) under drought and high temperature conditions.

Illustrations of the project

Picture 4. Effect of water stress on the transmission rate of two viruses: TuMV (UK1) and CaMV (BJI). Host plant: turnip (B. rapa). ** P-value < 0.001. Van Munster (unpublished).