ARABLE: Monitoring for emerging threats to UK OSR crops posed by novel variants and fungicide resistant strains of fungal pathogens

ARABLE：监测真菌病原体新变种和杀菌剂抗性菌株对英国 OSR 作物造成的新威胁

• 批准号: BB/X011917/1
• 负责人: Jon West
• 金额: $ 6.29万
• 依托单位: Rothamsted Research
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX011917%2F1
• 关键词: ARABLE; Monitoring; emerging; threats; UK

Oilseed rape (OSR) crops in the UK are threatened by two main fungal diseases: light leaf spot (LLS) caused by Pyrenopeziza brassicae (lineage 1) and Phoma caused by Plenodomus lingam / Plenodomus biglobosus. In the UK, Phoma and LLS each cause >£100M in crop losses despite costly fungicide applications (primarily DeMethylation Inhibitors (DMIs)). New variants and fungicide resistant strains of these pathogens have been reported recently from other geographic regions and may threaten UK OSR crops should they emerge there. The first P. brassicae risk relates to decreased fungicide sensitivity, where DMI resistance was found in European P. brassicae populations including the UK. Decreased DMI sensitivity is mediated by alterations in the CYP51 gene, including point mutations in the coding region (G460S or S508T) and inserts in the upstream control (promoter) region. Fungal isolates from Ireland with a G460S+S508T genotype had a much reduced DMI sensitivity. Therefore, work is required to monitor for changes in the fungicide sensitivity status of UK P. brassicae populations and screen for the G460S+S508T genotype. An additional risk from P. brassicae has recently identified a lineage 2 variant responsible for chlorotic leaf spot outbreaks in the US Pacific northwest. There lineage 2 appears to be a recent introduction that has undergone rapid invasive spread. This damaging variant now threatens adjacent Canadian OSR production and could affect European OSR production, particularly given the unknown implications of lineages 1 and 2 coming into contact and increasing use of brassica cover crop seed produced in the US Pacific northwest. Research is thus required to monitor the lineages currently present in UK pathogen populations. For Phoma, one threat to UK OSR comes from fungicide resistant P. lingam / P. biglobosus. Until 2015, in vitro testing had shown both pathogens to be sensitive to DMIs. However, recent work has shown DMI resistance in 15-24% of the P. lingam population in Australia and the Czech Republic. Such resistance is associated with inserts in the CYP51 promoter region. Whether DMI resistance has also emerged in P. lingam, and also P. biglobosus, pathogen populations in the UK requires investigation. A further Phoma threat relates to the recent discovery in Europe of the P. biglobosus 'canadensis' subclade. Prior to this only the P. biglobosus 'brassicae' subclade had been reported in Europe. There is increasing evidence that the P. biglobosus subclade variants pose different risks to OSR health, that may require distinct disease management strategies. Data is thus required on the pathogen population structure of subclades present in the UK OSR crops. In the proposed project, we will work with our collaborator, BASF who will collect OSR leaves from field trials showing Phoma (Jan 23) and LLS (Mar 23) symptoms. At least ten trials will be sampled from the UK and potentially some additional EU locations. Samples will be sent to RRes for fungal isolation, with the aim of collecting 50-100 isolates each of P. brassicae, P. lingam, and P. biglobosus . These isolates will be deposited into the RRes and OREGIN culture collections. Isolate DNA will be extracted, and P. brassicae strains lineage typed via lineage-specific amplification. Plenodomus isolates will be typed using species-specific DNA primers specific for P. lingam / P. biglobosus. For P. biglobosus isolates, the internal transcribed spacer (ITS) region will be sequenced to determine subclade (subgroup) identities. Isolates of all three species will be screened in vitro for sensitivity to fungicides, including DMIs (prothioconazole-desthio, mefentrifluconazole) and a QoI (pyraclostrobin), and for the least DMI sensitive isolates, CYP51 will be examined molecularly to explore possible resistance mechanisms.

英国的油籽强奸（OSR）农作物受到两种主要真菌疾病的威胁：叶肾上腺皮甲虫（谱系1）引起的轻叶斑点（LLS）和由plenodomus lingam / plenodomus lingam / plenodomos biglobosus引起的phoma。在英国，phoma和LLS各自导致农作物损失> 1亿英镑的目的地造成杀菌剂的应用（主要是脱甲基化抑制剂（DMI））。这些病原体的新变体和抗杀菌剂抗性菌株最近从其他地理区域报道了，如果它们出现在那里，可能会威胁英国OSR作物。与杀菌剂敏感性降低有关的第一个胸前假单胞菌风险，在包括英国在内的欧洲假单胞菌种群中发现了DMI耐药性。 DMI敏感性降低是由CYP51基因的改变介导的，包括编码区域（G460S或S508T）的点突变，并插入上游控制（启动子）区域中。来自爱尔兰的真菌分离株具有G460S+S508T基因型的DMI敏感性降低了。因此，需要工作以监视英国植物brassicae种群的杀菌剂敏感性状态的变化以及G460S+S508T基因型的筛查。 Brassicae的额外风险最近确定了一种谱系2变体，导致美国太平洋西北部的绿化叶斑暴发。谱系2似乎是最近引入的，它经历了快速侵入性扩散。现在，这种有害的变体威胁着邻近的加拿大OSR生产，并可能影响欧洲OSR的产量，特别是考虑到谱系1和2的未知含义，即接触并增加使用美国太平洋西北部生产的甘蓝种子。因此，需要研究以监测英国病原体种群中目前存在的谱系。对于Phoma而言，对英国OSR的威胁来自耐杀菌剂P. lingam / p。biglobosus。直到2015年，体外测试均显示两种病原体对DMI敏感。但是，最近的工作表明，澳大利亚和捷克共和国的林加姆人口中有15-24％的DMI抵抗力。这种电阻与CYP51启动子区域中的插入物有关。 DMI耐药性是否也在P. lingam以及Biglobosus中出现，英国的病原体种群需要投资。 phoma的进一步威胁与最近在欧洲发现的Biglobosus'Canadensis'子基团有关。在此之前，仅在欧洲报道了Biglobosus'Brassicae'Brassicae'Brassicae'。有越来越多的证据表明，大斑杆菌子基金会变体对OSR健康构成不同的风险，这可能需要不同的疾病管理策略。因此，需要对英国OSR作物中存在的子基质的病原体种群结构进行数据。在拟议的项目中，我们将与我们的合作者巴斯夫合作，巴斯夫将从现场试验中收集OSR叶子，显示Phoma（1月23日）和LLS（3月23日）符号。至少将从英国采样十项试验，并有可能其他一些欧盟地点进行采样。样品将被发送到RRES进行真菌分离，目的是收集50-100个分离株，每种甘蓝植物，P。lingam和P. biglobosus。这些分离株将沉积在RRES和Oregin培养物收集中。所有三种物种的分离株将在体外进行筛查，以使其对杀真菌的敏感性，包括DMI（促螺旋可康可唑 - desthio，mefentrifluconazole）和QOI（pyraclostrobin），并且对于最少的DMI敏感分离株，CYP51将在分子上检查分子，以探索可能的耐药机制。