title: Reduction of leaf area and symptom severity as proxies of disease-induced plant mortality: the example of the Cauliflower mosaic virus infecting two Brassicaceae hosts.
abstract: Disease induced effects on host survival are important to understand the evolution of parasitic virulence and host resistance/tolerance. Unfortunately, experiments evaluating such effects are in most cases logistically demanding justifying the measurement of survival proxies. For plant hosts commonly used proxies are leaf area and the nature and severity of visual qualitative disease symptoms. In this study we tested whether these traits are indeed correlated to the host mortality rate induced by viral infection. We infected Brassica rapa and Arabidopsis thaliana plants with different natural isolates of Cauliflower mosaic virus (CaMV) and estimated over time the development of symptoms and the relative reduction of leaf area compared to healthy plants and followed plant mortality. We observed that the mortality of infected plants was correlated with the relative reduction of leaf area of both B. rapa and A. thaliana. Measures of mortality were also correlated with the severity of visual qualitative symptoms but the magnitude of the correlations and the time frame at which they were significant depended on the host plant: stronger and earlier correlations were observed on A. thaliana.
authors.affiliation: Laboratoire "Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle" (MIVEGEC), UMR 5290 CNRS-IRD-UM1-UM2, 911 Avenue Agropolis, 34394 Montpellier, France.
authors.forename: Juliette
authors.initials: J
authors.lastname: Doumayrou
authors.forename: Sophie
authors.initials: S
authors.lastname: Leblaye
authors.forename: Rémy
authors.initials: R
authors.lastname: Froissart
authors.forename: Yannis
authors.initials: Y
authors.lastname: Michalakis
mesh_terms: D017360:Arabidopsis / Q000502:physiology / Q000821:virology*; D015415:Biomarkers; D029741:Brassica rapa / Q000502:physiology / Q000821:virology*; D017796:Caulimovirus / Q000254:growth & development*; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000502:physiology / Q000821:virology*; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D015415:Biomarkers
keywords: Arabidopsis thaliana; Brassica rapa; Cauliflower mosaic virus; Mortality proxies; Virulence