Towards a phylogenetic ecology of plant pests and pathogens: using evolutionary history to model species interactions

植物害虫和病原体在构建生态群落中发挥着重要作用;然而，本地和外来害虫都对野生和管理系统施加了重大压力，并对粮食安全构成威胁。气候变暖可能会进一步增加未来病虫害爆发的范围、频率和严重程度。因此，迫切需要扩展当前的理论以应对这些挑战。在这里，我建议开发一个新的系统发育框架的研究植物和害虫的相互作用。在植物中，越来越多的研究表明，宿主进化的相关性--寄生性--强烈地构建了病原体的宿主范围。这种系统发育结构的后果是深远的。例如，病原体传播的速率将由群落中宿主物种的分类组成介导，而非本地害虫建立的可能性可以从其引入范围内的植物物种与其本地范围内的植物物种之间的系统发育相关性来估计。此外，我们预测，来自本地害虫对农作物的疾病压力将与作物物种从本地植物群落的进化独特性负协变，而入侵植物的传播将与它们的进化独特性正协变。这项研究的一个主要目标是提高我们目前对植物中寄主-害虫关联的理解，更好地预测新出现的植物害虫的疾病影响，并指导积极主动的害虫监测。首先，我的目标是利用现有的植物害虫数据库和一个大型的植物系统发育的植物害虫相互作用的系统发育结构来描述整个植物的生命树害虫的系统发育分布。然后，我将使用这些数据来模拟害虫在植物宿主之间共享的可能性，并根据分离宿主物种的进化距离来重新定义害虫的宿主宽度。其次，我将使用大量的历史记录保存在植物标本馆收藏的模型转移病虫害的压力，随着时间的推移，并使用这个模型来生成预测的害虫主机扩展，然后可以在现场验证。第三，我将评估系统发育的主机宽度和毒力之间的关系，使用实验交叉感染的葡萄酒，葡萄真菌病原菌Botryosphaeriaceae作为模型系统。我上面概述的拟议框架有望为作物疾病和害虫风险模型提供信息，改善对入侵物种传播和本地物种中新出现的病原体爆发的预测，并有助于我们对物种共存以及害虫和病原体在调节自然群落多样性方面的重要性的基本理解。

Plant pests and pathogens play an important role in structuring ecological communities; yet both native and introduced pests impose significant pressure on wild and managed systems, and pose a threat to food security. A warming climate is likely to further increase the range, frequency and severity of pest and disease outbreaks in the future. There is a critical need, therefore, to expand on current theory to address these challenges. Here, I propose to develop a novel phylogenetic framework for the study of plant and pest interactions. In plants, a growing body of work has suggested that host evolutionary relatedness-phylogeny-strongly structures pathogen host range. The consequences of such phylogenetic structuring are profound. For example, rates of pathogen spread will be mediated by the taxonomic composition of the host species in a community, and the likelihood of non-native pest establishment may be estimated from the phylogenetic relatedness between the plant species in its introduced range and those in its native range. In addition, we would predict that disease pressure on agricultural crops from native pests will covary negatively with the evolutionary distinctiveness of the crop species from the native plant community, while the spread of invasive plants will covary positively with their evolutionary distinctiveness. A major goal of this research is to improve on our current understanding of host-pest associations in plants, better predict disease impacts of new and emerging plant pests, and guide proactive pest surveillance. First, I aim to characterise the phylogenetic structure of plant-pest interactions using existing plant-pest databases and a mega-phylogeny for plants to describe the phylogenetic distribution of pests across the plant tree-of-life. I will then use these data to model the likelihood of pest sharing among plant hosts, and to redefine the host breadth of pests based on the evolutionary distances separating host species. Second, I will use the vast historical record housed in herbarium collections to model shifting pest and disease pressures through time, and use this model to generate predictions of pest host-expansion which can then be validated in the field. Third, I will evaluate the relationship between phylogenetic host-breadth and virulence using experimental cross infections of the wine-grape fungal pathogen Botryosphaeriaceae as a model system. The proposed framework I outline above holds promise to inform models of disease and pest risk in crops, improve prediction of invasive species spread and emerging pathogen outbreaks in native species, and contribute to our fundamental understanding of species coexistence and the importance of pests and pathogens in regulating diversity in natural communities.