Data from: 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

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.

疾病对宿主存活的诱导效应，对于解析寄生致病力与宿主抗性、耐受力的演化过程具有重要意义。然而，针对此类效应的实验研究在多数情况下受限于操作复杂性与资源成本，因此采用存活替代指标进行测定便具备合理性。对于植物宿主而言，常用的存活替代指标包括叶面积，以及直观定性病害症状的类型与严重程度。本研究旨在验证上述性状是否与病毒感染诱导的宿主死亡率存在关联。我们利用不同自然分离株的花椰菜花叶病毒（Cauliflower mosaic virus, CaMV）分别侵染芜菁（Brassica rapa）与拟南芥（Arabidopsis thaliana），并随时间进程评估病害症状发展情况、相较于健康植株的叶面积相对缩减率，同时追踪植株死亡率变化。研究结果表明，两种宿主的受侵染植株死亡率均与其叶面积相对缩减率显著相关。死亡率测定结果同样与直观定性病害症状的严重程度相关，但关联强度与显著关联的时间窗口因宿主植物而异：在拟南芥中观测到的关联更强且出现时间更早。