Strategies for Quantifying and Controlling Free Living Nematode Populations and Consequent Damage by Tobacco Rattle Virus to Improve Potato Yield and

自由生活线虫(Fln)正成为英国马铃薯种植者面临的一个主要问题，短期内，由于移除批准的杀线虫剂和遵守《水框架指令》中的严格立法，这一问题加剧，长期而言，由于气候变化，预计Fln种群将增加。通过取食马铃薯根部直接危害，降低产量和品质，通过传播烟草鼠疫病毒(TRV)间接危害。相对较低的TRV感染水平可能会使整个农作物对生鲜和加工行业无法销售。Fln包括一系列不同的分类学组，这些组在视觉上很难区分，但在分布、致病性和病毒传播频率方面差异很大，到目前为止，英国一直在进行研究。有益的和致病的FLN物种共存使问题进一步复杂化，因此准确的区分是至关重要的。该联盟的总体目标是为英国马铃薯行业提供一套针对FLN和相关的TRV作物损害的综合新型有害生物综合管理(IPM)方案。其结果将产生立竿见影的效果，从而改善与马铃薯品种和田地选择相关的管理决策，以最大限度地减少直接饲养特定群体的FLN造成的损失，以及与饲养和TRV感染相关的质量损失。它还将通过减少TRV造成的破坏造成的浪费以及91/414/EEC产生的杀虫剂使用量来提高英国主要马铃薯生产商的生产率。这个项目中的科学研究被分成三个综合的工作包。我们将开发、测试和验证一种定量分子诊断方法，该方法将在普通水平上区分TRV的媒介副圆线虫和Trichodorus线虫，并使用现场样本作为比较器进行验证，该方法可以区分两个常见的TRV分离物-TRV-PpK20和TRV-Tp01。穿透细线虫是一种半寄生线虫，越来越多地与马铃薯作物的危害有关，将开发、测试和验证一种新的分子诊断方法。对马铃薯可持续生产的关键是了解这些线虫种群的危害阈值。将在英国各地的6个地点进行田间试验，以评估这些危害阈值，并将在4个地点进行试验，以评估20个马铃薯品种(6个脆、6个加工、6个鲜食和2个其他对照品种)对线虫危害的抗性和耐性。可能替代传统杀线虫剂的方法，包括芥末‘生物熏蒸剂’作物、抗线虫油萝卜品种、抗TRV油萝卜品种、使用贝类废弃物作为土壤改良剂作为生物熏蒸剂、从芥末和辣椒中提取的新型杀线虫剂、萜烯、植物防御诱导剂(Harpin)和一种标准杀线虫剂将在两个地点进行试验。最终，该项目的主要目标是确定TRV抗性的分子标记。该项目将利用包括DART、SNP和AFLP在内的分子标记系统。最初，我们将分析两个目标人群中的大量抗性和易感基因。对这两个不同群体的基因类型(亲本材料和衍生群体中的基因类型)的筛选几乎肯定会识别目标TRV抗性性状的变异。一项初步研究的初步结果有力地表明了抗性和喷洒敏感性的显著遗传因素。这将直接导致对育种者友好的分子标记的开发，这种标记可以在更多的植物上进行测试。成功地提供了这种针对TRV抗性的分子标记，这将向下游传递到未来的马铃薯育种计划，这是该项目总体成功的关键。

Free Living Nematodes (FLN) are emerging as a major problem for UK potato growers, exacerbated in the short term by removal of approved nematicides and adherence to stringent legislation within the Water Framework Directive and in the long-term by expected FLN population increases due to climate change. FLN cause direct damage by feeding on potato roots which reduces yield and quality, and indirectly by transmitting Tobacco Rattle Virus (TRV). Relatively low levels of TRV infections can render entire crops unsaleable for the fresh and processing industries. FLN comprise a range of different taxonomic groups that are difficult to distinguish visually but vary significantly in terms of their distribution, pathogenicity and virus transmission frequencies, and have been to date under-studied in the UK. The problem is further compounded by beneficial and pathogenic FLN species co-existing, and thus accurate discrimination is essential. This consortium has the overarching objective to provide the UK potato industry with an integrated novel Integrated Pest Management (IPM) package for FLN and associated TRV crop damage. The outcomes will have immediate utility and thus direct economic benefit by improving management decisions related to choice of potato variety and field to minimise losses caused by direct feeding of specific groups of FLN, and quality losses associated with feeding and TRV infections. It will also improve the productivity of the UK's major potato producers by decreasing wastage caused by damage due to TRV, as well as reducing pesticide usage arising from 91/414/EEC. The scientific research within this project is split across three integrated work packages. We will develop, test, and validate a quantitative molecular diagnostic that will discriminate between Paratrichodorus and Trichodorus nematodes, the vectors of TRV, at the generic level as well as validate using field-based samples as a comparator using a unique molecular diagnostic for TRV that can distinguish between two common isolates TRV-PpK20 and TRV-Tp01. A novel molecular diagnostic for Pratylenchus penetrans, a semi-endoparasitic nematode species, increasingly associated with damage to potato crops will be developed, tested and validated. Crucial to sustainable potato production is the understanding of the damage thresholds for these nematode groups. Field trials will be conducted at 6 sites across the UK to assess these damage thresholds, and trials at 4 sites will be conducted to evaluate the resistance and tolerance of 20 potato varieties (6 crisping, 6 processing, 6 fresh and 2 other control varieties) to nematode damage. Potential alternative treatments to conventional nematicides, including mustard 'biofumigant' crops, a nematode resistant oil radish variety, a TRV-resistant oil radish variety, application of shellfish waste as a soil amendment as a biofumigant, novel nematicides derived from mustard and chilli, terpenes, plant defence elicitors (harpin), and a standard nematicide will be trialled at 2 sites. Ultimately, the primary goal of the project is to identify molecular markers for TRV resistance. The project will utilise molecular markers systems including DArT, SNP and AFLP. Initially 'bulks' of resistant and susceptible genotypes within two target populations will be analysed. The screening of these two diverse populations of genotypes (parental material and genotypes within derived populations) will almost certainly identify variation for the target TRV resistance traits. Preliminary results from a pilot study gave strong indications of significant heritable factors for resistance and for spraing susceptibility. This will lead directly to development of 'breeder friendly' molecular markers that can be tested on larger numbers of plants. The success in delivering such molecular markers for TRV resistance, which would cascade downstream into future potato breeding programs, is key for the overall success of the project.