Assessment of pathogen impacts on novel forestry species and provenances in the UK to aid understanding of future commercial potential

在过去的十年里，英国的生产林业发现自己处于脆弱的地位，因为入侵病原体的流行，如落叶松上的枝疫霉菌和松树上的七孢子菌，缩小了商业上可行的木材树种的范围。这一点，再加上气候变化预计的直接影响，引发了人们对英国林业生产中“未来预测”水平的严重怀疑。替代树种可能适合于满足英国林业的木材利用需求，但缺乏信息是物种选择的主要障碍。最近的证据表明，病原体的影响是评估森林复原力的一个关键因素。自2012年以来，森林研究(FR)已经开发了几个在英国不同地点种植的新兴和本地生产林业树种的试验，以测试性能并评估它们面对21世纪挑战的潜在适宜性。初步健康评估表明，物种和种源对广泛的地方性和侵袭性病原体的反应明显不同，其中一些被证明对健康有重大影响，新的病原体可能已经从欧洲大陆引入种植材料。本博士项目将确定影响替代林业物种健康的关键病原体，影响其影响的主要生物学因素，以及减轻进口病原体对外来繁殖材料的风险的做法。研究结果将被用来支持关于未来物种是否适合商业林业的决策，并为苗圃繁殖的最佳实践提供参考。博士项目的目标是：i)确定在英国各地种植的替代林业物种试验中造成损害的关键病原体，以及影响病原体影响的宿主和环境因素。二)进一步审查优先“新兴”商品林种/种源对实地调查中确定的主要病原体的表型和遗传反应。三)与两个林业伙伴合作，确定哪些病原体对森林和苗圃中的主要林业物种/种源构成最大风险，并确定最佳苗圃做法，以避免这些病原体在采种、育苗或栽植阶段出现。目标(I)将利用已经建立的FR(24个物种)试验和欧盟REINFFORCE项目(30个物种)试验，这些试验在2012至2015年间种植，并在英国五个纬度和经度不同的地点复制，以调查病原体与环境对每个宿主的相互作用。每个接受调查的试验都将对损害指标进行评分，如果无法现场识别，将使用形态和分子技术相结合的方式收集样本，以确定损害症状的原因。这项工作将产生一系列分离株和相关的基因数据，作为重要的项目产出。统计分析将根据产地和地理位置确定对关键病原体的易感性的差异。调查结果将与宿主来源地区的国家数据集和文献进行比较。对于目标(Ii)，将使用温室接种试验和分子分析来调查优先病原体/宿主组合，以确定影响感染结果的表型和遗传因素。分子分析，如RNA测序分析、DNA甲基化和次生代谢物水平的测定，将用于确定表型差异和对接种的反应。在选定物种中进行的种源试验将有助于进一步分析遗传与环境的相互作用，DNA指纹图谱将有助于评估种源之间的遗传多样性水平。对于目标(Iii)，该项目开始与两个行业合作伙伴合作，他们都希望更好地了解病原体对

Over the last ten years, UK production forestry has found itself in a vulnerable position as epidemics of invasive pathogens such as Phytophthora ramorum on larches and Dothistroma septosporum on pines have narrowed the range of commercially viable timber species. This, added to the predicted direct effects of climate change, has raised serious doubts as to the level of 'future proofing' in UK production forestry. Alternative tree species may be suited to meeting timber utilization demands of UK forestry but the lack of information is a major barrier for informed species selection. Recent evidence shows that impacts of pathogenic agents is a key factor when assessing forest resilience.Since 2012, Forest Research (FR) has developed several trials of emerging and native production forestry species planted at different locations across Britain to test performance and assess their potential suitability in face of 21st Century challenges. Preliminary health assessments indicate that species and provenances differ markedly in their responses to a broad range of endemic and invasive pathogens, some of which are shown to have significant health impacts, and that new pathogens may have been introduced on planting material from continental Europe.This PhD project will identify the key pathogens affecting the health of alternative forestry species, the main biological factors influencing their impact, and practices that mitigate the risk of importing pathogens on exotic propagation material. Findings will be used to underpin decisions on future species suitability for commercial forestry and to inform nursery propagation best practice. The objectives of the PhD project are to:i) Identify the key pathogens causing damage in alternative forestry species trials planted across Britain, and the host and environment factors influencing pathogen impact. ii) Further examine priority 'emerging' commercial forestry species/provenances for their phenotypic and genetic responses to the key pathogens identified in the field surveys. iii) Work with two forest industry partners to determine which pathogens pose greatest risk to key forestry species/seed provenances in the forest and nursery and identify best nursery practices to avoid these pathogens occurring at seed collection, seedling or planted out stages. Objective (i) will utilise the already established FR (24 species) trials and EU REINFFORCE project (30 species) trials planted between 2012 and 2015 and replicated at five locations in Britain varying in latitude and longitude allowing investigation of pathogen x environment interaction on each host. Each surveyed trial will be scored for damage indicators and samples will be collected to determine the causal agents of damage symptoms if field identification is not possible, by using a combination of morphological and molecular techniques. This work will result in a collection of isolates and associated genetic data as important project outputs. Statistical analyses will determine variation in susceptibility to key pathogens according to provenance and geographical location. Findings will be compared to national datasets and literature in the host source region.For objective (ii), priority pathogen/host combinations will be investigated using greenhouse inoculation trials and molecular analyses to determine phenotypic and genetic factors influencing the outcome of infection. Molecular analyses such as RNA-Sequencing analyses, DNA methylation and determinations of secondary metabolite levels will be used to determine phenotypic differences and responses to inoculation. Provenance trials available in selected species will enable further analysis of genetic x environment interaction and DNA finger-printing will serve to assess the levels of genetic diversity among sources of provenance. For objective (iii) the project sets out to work with two industry partners who both wish to gain a greater understanding of pathogen threats to