Keeping the leaves on: investigating disease threats to trees

树木提供了许多生态系统效益，包括土壤健康、庇护所和食物。植树通常被认为是一种隔离大气二氧化碳从而减缓气候变化的方法。作为长寿有机体，树木在其一生中都受到疾病的威胁，有可能限制它们的碳捕获潜力。植物疫霉(Phytophthora)是一种破坏性的植物病原菌，广泛存在于树木的病原中。这些病原体是新出现的威胁，由于人类活动和气候变化，它们正变得越来越普遍。由不同疫霉物种引起的树木疾病的外在症状可能非常相似，但我们对每一物种在树木上定居并导致疾病时所使用的潜在机制的了解是基本的。深入了解疫霉对树木的侵染对于确定培育抗病育种方案是否可行至关重要。在这个项目中可以进行三个方面的研究：1.我们能够从基因上转化疫霉物种以表达荧光标记。本研究的目的是获得不同树种致病疫霉的标记菌株，并跟踪模式植物本氏烟草和自然寄主的根、茎和叶组织的侵染情况。共聚焦显微镜或超分辨率显微镜可以用来确定这些病原体如何随着感染的进展进入和离开不同的组织类型。毒力蛋白(称为效应物)在树木病害中的作用在很大程度上是未知的，特别是当病原体定植在木质组织中时。对分泌到植物维管组织中的疫霉蛋白的蛋白质组学分析将被用来揭示不同疫霉物种对树木定殖的共同/不同的候选效应。候选效应蛋白既可以沉默，也可以用CRISPR-Cas敲除，以确定它们对不同组织类型的树木疫霉感染的重要性。这一目标将集中在不同树致病疫霉之间的共同效应者候选。这项研究与新西兰疫霉研究实验室正在进行的合作交流相联系，并在博士项目期间有实验室间旅行的空间。许多这些新出现的疾病威胁都与新西兰分享。该项目将提供一系列实验室技能和技术的培训，包括分子生物学、微生物学、植物转化、尖端显微镜和细胞生物学。将支持学生介绍他们的工作，并鼓励他们遵循文献并为研究讨论做出贡献。我们的团队是大学里的，支持的，并且涵盖了广泛的经验。

Trees provide many ecosystem benefits, including for soil health, shelter, and food. Tree planting is often proposed as a method to sequester atmospheric carbon dioxide and thus mitigate climate change. As long-lived organisms, trees are threatened by disease throughout their lives, with the potential to limit their carbon capture potential. The destructive genus of plant pathogens, Phytophthora, is prevalent among disease agents of trees. These pathogens are emerging threats that are becoming more widespread due to human activity and climate change. The outward symptoms of tree disease caused by different Phytophthora species can be very similar, but our knowledge of the underlying mechanisms used by each species as they colonise and cause disease in trees is rudimentary. A deeper understanding of Phytophthora infection of trees is crucial to establishing whether breeding programmes to develop disease resistance are viable options.Three lines of research can be followed in this project:1. We are able to genetically transform Phytophthora species to express fluorescent markers. The aim in this objective is to generate tagged strains of different tree pathogenic Phytophthora species and follow infection of root, stem, and leaf tissue in the model plant Nicotiana benthamiana and in natural tree hosts. Confocal, or super-resolution microscopy can be used to determine how these pathogens enter and exit different tissue types as infection progresses.2. The role of virulence proteins (called effectors) in tree disease is largely unknown, especially while the pathogen is colonising woody tissues. Proteomic analyses of Phytophthora proteins secreted into plant vascular tissue will be used to reveal candidate effectors that are common/distinct to tree colonisation by different Phytophthora species.3. Candidate effector proteins can be either silenced, or knocked out using CRISPR-Cas, to determine their importance to Phytophthora infection of different tissue types in tree hosts. This objective will focus on effector candidates in common between different tree pathogenic Phytophthoras.This research links with ongoing collaborative exchanges with New Zealand Phytophthora research laboratories, and there is scope for inter-lab travel during the PhD project. Many of these emerging disease threats are shared with New Zealand.The project will provide training in a range of laboratory skills and techniques, including molecular biology, microbiology, plant transformation, cutting-edge microscopy, and cell biology. The student will be supported to present their work and encouraged to follow the literature and contribute to research discussions. Our group is collegiate, supportive, and covers a broad range of experience.