Résumé
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.