IGEPP, INRA, Agrocampus Ouest, Université Rennes 1, Le Rheu, France.
Proc Biol Sci. 2019 Oct 9;286(1912):20191244. doi: 10.1098/rspb.2019.1244. Epub 2019 Oct 2.
Assessing life-history traits of parasites on resistant hosts is crucial in evolutionary ecology. In the particular case of sporulating pathogens with growing lesions, phenotyping is difficult because one needs to disentangle properly pathogen spread from sporulation. By considering on potato, we use mathematical modelling to tackle this issue and refine the assessment of pathogen response to quantitative host resistance. We elaborate a parsimonious leaf-scale model by convolving a lesion growth model and a sporulation function, after a latency period. This model is fitted to data obtained on two isolates inoculated on three cultivars with contrasted resistance level. Our results confirm a significant host-pathogen interaction on the various estimated traits, and a reduction of both pathogen spread and spore production, induced by host resistance. Most interestingly, we highlight that quantitative resistance also changes the sporulation function, the mode of which is significantly time-lagged. This alteration of the infectious period distribution on resistant hosts may have strong impacts on the dynamics of parasite populations, and should be considered when assessing the durability of disease control tactics based on plant resistance management. This inter-disciplinary work also supports the relevance of mechanistic models for analysing phenotypic data of plant-pathogen interactions.
评估具有抗性宿主的寄生虫的生活史特征在进化生态学中至关重要。在具有生长病变的孢子形成病原体的特殊情况下，表型分析很困难，因为需要正确区分病原体传播和孢子形成。通过考虑马铃薯上的病原体，我们使用数学建模来解决这个问题，并改进对病原体对定量宿主抗性的反应的评估。我们在潜伏阶段之后，通过卷积病变生长模型和孢子形成函数来构建一个简洁的叶片尺度模型。该模型适用于接种在三个具有不同抗性水平的品种上的两个分离株获得的数据。我们的结果证实了各种估计特征上的显著的宿主-病原体相互作用，以及宿主抗性引起的病原体传播和孢子产生的减少。最有趣的是，我们强调定量抗性也会改变孢子形成函数，其模式明显滞后。这种在抗性宿主上的传染性期分布的改变可能会对寄生虫种群的动态产生强烈影响，并且在评估基于植物抗性管理的疾病控制策略的耐久性时应考虑到这一点。这项跨学科工作还支持使用机制模型分析植物-病原体相互作用的表型数据的相关性。
