Arable - Are chitin amendments to soil a means to control potato cyst nematodes?

植物寄生线虫每年给全球农业造成约800亿美元的损失，并威胁许多地区的粮食安全。马铃薯孢囊线虫（PCN）是一种植物寄生线虫，感染茄科物种并造成重大损害，主要是对马铃薯作物。仅在英国，PCN每年造成的损失就超过3100万英镑。历史上，多氯化萘一直通过使用杀线虫剂进行管理。然而，由于潜在的环境问题，这些化学品已受到严格管制。目前，英国市场上只剩下一种颗粒状杀线虫剂，随着2024年即将进行的监管审查，这一前景不确定。苏格兰是马铃薯种薯的主要生产国和出口国。现行法规规定，如果在一块田地中检测到多氯化萘，则该田地不能再用于马铃薯种薯生产。多氯化萘正在种子种植区蔓延，最近的预测表明，如果没有改进的多氯化萘管理工具，这个行业将在2050年崩溃。几丁质是一种丰富的生物分子，存在于昆虫、真菌和贝类中。几丁质也存在于PCN蛋壳中，通过提供蛋壳的硬度和拉伸强度来保护发育中的幼仔。以前已经提出了几丁质土壤改良剂用于控制植物寄生线虫。在土壤中添加几丁质可能有助于选择几丁质降解微生物种群，自然提高这些生物在该环境中的流行程度。微生物可能随后使用来源的甲壳素已经存在于土壤中，如PCN蛋壳，作为能源，允许抑制的PCN数量的水平，他们不再是一个威胁到马铃薯cropp.We目前不知道，如果甲壳素土壤改良剂是适合苏格兰的生长条件或影响，他们对有益的，含几丁质，土壤生物。在这项工作中，我们将调查是否几丁质土壤改良剂控制英国土壤中的多氯化萘，以及如何实现这种控制。将从使用或不使用几丁质土壤改良剂处理的田间地块收集土壤样品。这些样品将用于确定不同的真菌，细菌和自由生活的线虫种群的存在，并量化多氯化萘数量和几丁质降解活性。比较处理过的和未处理过的样本将有助于了解多氯化萘种群的变化、哪些微生物负责以及是否对更广泛的土壤生物多样性产生负面影响。在受控温室环境中进行的测试将确认土壤改良剂中的甲壳素是否对通过蛋壳降解减少多氯化萘种群具有积极影响，并将确认哪些微生物对此负有责任，项目成果将包括确定在使用或不使用富含甲壳素的土壤改良剂的情况下，田间样本中微生物和线虫种群的差异。分析土壤样品中几丁质酶（负责几丁质降解的酶）的增加，将确认用于降解PCN蛋壳的途径。此外，对多氯化萘蛋壳的结构研究将验证蛋壳是否充分降解，以防止多氯化萘孵化。将在处理和未处理的样品中确定潜在有益的自由生活线虫种群，以调查几丁质基土壤改良剂的潜在更广泛的杀线虫作用。

Summary:Plant parasitic nematodes cause an estimated $80 billion of annual damage to global agriculture and threaten food security in many regions. The potato cyst nematode (PCN) is a plant parasitic nematode that infects solanaceous species and causes significant damage, primarily to potato crops. In the UK alone, PCN causes more than £31 million in damage annually. Historically, PCN has been managed by using nematicides. However, due to potential environmental concerns, these chemicals have become tightly regulated. Currently there is only one granular nematicide left on the UK market and this has an uncertain future with an upcoming regulation review in 2024. Scotland is a large producer and exporter of seed potatoes. Current regulations state that if PCN has been detected in a field, that field can no longer be used for seed potato production. PCN is spreading in seed growing areas and recent predictions suggest that without improved PCN management tools this industry will collapse by 2050.Chitin is an abundant biomolecule which is found in insects, fungi and shellfish. Chitin is also present in PCN eggshells where it protects the developing juvenile by providing the eggshell with rigidity and tensile strength. Chitinous soil amendments have previously been proposed for control of plant parasitic nematodes. Addition of chitin to soils may help select for chitin-degrading microbial populations, naturally raising the prevalence of these organisms in that environment. The microbes may subsequently use sources of chitin already present in the soil, such as PCN eggshells, as an energy source, allowing the suppression of PCN numbers to a level where they are no longer a threat to the potato crop.We currently do not know if chitinous soil amendments are suitable for Scottish growing conditions or the impact they have on beneficial, chitin-containing, soil organisms. In this work we will investigate whether chitinous soil amendments control PCN in UK soils and how this control is achieved. Soil samples from field plots treated either with or without chitinous soil amendments will be collected. These samples will be used to identify the presence of different fungal, bacterial and free-living nematode populations and to quantify PCN numbers and chitin degrading activity. Comparing treated and untreated samples will allow understanding of changes in PCN populations, which microorganisms are responsible and if there is a negative impact on wider soil biodiversity. Testing in a controlled greenhouse environment will confirm whether the chitin within the soil amendment has a positive effect towards reducing PCN populations through eggshell degradation and will confirm which microorganisms are responsible.The project outcomes will include identifying differences in microbial and nematode populations in field samples treated with or without a chitin-rich soil amendment. Analysis of the increased presence of chitinase, the enzyme responsible for chitin degradation, in soil samples will confirm the pathway utilised to degrade PCN eggshells. Additionally, structural investigation of PCN eggshells will validate whether eggshells are degraded sufficiently to prevent PCN hatching. Populations of potentially beneficial free-living nematodes will be identified in treated and untreated samples to survey for potential wider nematocidal effects of chitin-based soil amendments.