Non-Destructive Detection of Below-Ground Plant Pathogens: VOC Profiling by Frequency Comb Spectroscopy

地下植物病原体的无损检测：通过频率梳光谱进行 VOC 分析

• 批准号: BB/V017306/2
• 负责人: Julia Lehman
• 金额: $ 12.15万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FV017306%2F2
• 关键词: Non; Destructive; Detection; Below; Ground

Research into pests and diseases is essential to fulfil the goal of ensuring food security. Aerial pests and disease are easier to quantify and identify. However, the detection and determination of the pathogen burden is far more difficult for soil-borne organisms. An example are the plant parasitic nematodes that have devastating impacts on plant productivity throughout the world. This is an issue both in research and strategically in the field. Currently sampling methods are time consuming, destructive and costly. New methods of detection are urgently required to speed up research into these pathogens.Plant parasitic nematodes represent an important global threat to agricultural production. Despite this, as soil-borne pathogens plant parasitic nematodes are classically under-diagnosed. The nematodes display a wide range of parasitic strategies. Some feed destructively as they move through plant roots whilst others reprogramme root cells to form a novel nutrient sink from which they feed for many weeks. These diverse parasitic strategies result in differing levels of direct plant damage and changes to plant physiology and thus are likely to elicit different plant responses. Plant parasitic nematodes are therefore an excellent patho-system around which to develop and test a novel system for detection and diagnosis of plant disease. Volatile organic compounds (VOCs) are abundant chemicals that are emitted by organisms in all terrestrial and marine ecosystems. The chemical composition of plant-emitted VOCs and their abundance can carry information about the plants' physiological status and the stresses to which they have been subjected. VOCs are an essential part of plant defense systems and are emitted in response to pest and pathogen attack. We have established that plants release VOCs in response to infection by plant-parasitic nematodes and propose to develop new technology to detect and monitor VOCs in order to establish a VOC 'fingerprint' for nematode infection. Infrared spectroscopy acts as a chemical 'fingerprinting' mechanism since every molecule that can absorb infrared light does so at specific, unique frequencies. However, VOCs emitted by plants are oftentimes in the low parts-per-billion (ppb) levels, which can test the limits of instrumentation sensitivity, and the overlapping infrared spectra of different VOCs can be an issue for low spectral resolution techniques. A new frequency comb laser-Fourier transform infrared spectrometer (FC-FTIR) will be built to reach the necessary ppb level molecular sensitivities by using a long interaction path length, with the molecular selectivity being a result of the simultaneously broadband and high resolution infrared laser. Thus, the infrared spectra collected with FC-FTIR can yield information about an overall profile of plant VOCs emitted, and even the identity and quantity of the VOCs. Statistical analysis of healthy versus infected plant VOC emission profiles will aid in determining the relative health of the plant and potentially linking the emission profile to a specific plant pathogen. This work addresses the current need to move towards a technology that is both sensitive and selective in order to identify a profile of plant VOCs emitted under different pathogen burdens, while still being general enough to detect all possible emitted VOCs (i.e. not targeting a specific VOC composition based on an assumed plant disease). This technology potentially allows the identification of a broad range of plant pathogens in a non-destructive manner, in real time. It therefore has impact across a wide range of biological disciplines in plant science and beyond. Ideally, this instrument would also be able to monitor VOC profiles in the field in order to locate infected areas within crops because of the highly directional nature of using a coherent light source, ensuring a rapid response for remedial action thus minimizing infection impact and mitigating crop loss.

害虫和疾病研究对于实现确保粮食安全的目标至关重要。空中传播的害虫和疾病更容易量化和识别。然而，检测和确定病原体负荷对于土传生物来说要困难得多。一个例子是植物寄生线虫，对世界各地的植物生产力具有破坏性影响。这既是一个研究问题，也是一个战略问题。目前的取样方法费时、破坏性大、成本高。植物寄生线虫是全球农业生产面临的一个重要威胁。尽管如此，作为土传病原体，植物寄生线虫通常诊断不足。线虫显示出广泛的寄生策略。一些破坏性饲料，因为他们通过植物根部移动，而其他人重新编程根细胞，形成一个新的营养库，他们从饲料许多星期。这些不同的寄生策略导致不同程度的直接植物损害和植物生理变化，因此可能引起不同的植物反应。因此，植物寄生线虫是一个优秀的病理系统，围绕它开发和测试一个新的系统，用于检测和诊断植物疾病。挥发性有机化合物（VOCs）是陆地和海洋生态系统中生物体排放的大量化学物质。植物排放的VOCs的化学组成及其丰度可以携带有关植物生理状态和它们所受到的胁迫的信息。挥发性有机化合物是植物防御系统的重要组成部分，并在害虫和病原体攻击时释放。我们已经确定，植物释放挥发性有机化合物在响应植物寄生线虫感染，并建议开发新的技术来检测和监测挥发性有机化合物，以建立一个挥发性有机化合物的“指纹”线虫感染。红外光谱作为一种化学“指纹”机制，因为每一个可以吸收红外光的分子都是在特定的、独特的频率下吸收红外光的。然而，由植物排放的VOC通常处于低十亿分之一（ppb）水平，这可以测试仪器灵敏度的极限，并且不同VOC的重叠红外光谱对于低光谱分辨率技术可能是一个问题。将建立一种新的频率梳激光傅里叶变换红外光谱仪（FC-FTIR），以达到必要的ppb级的分子灵敏度，通过使用长的相互作用路径长度，与分子的选择性是同时宽带和高分辨率的红外激光的结果。因此，使用FC-FTIR收集的红外光谱可以产生关于植物挥发性有机化合物排放的总体概况的信息，甚至是挥发性有机化合物的身份和数量。健康与受感染植物VOC排放曲线的统计分析将有助于确定植物的相对健康状况，并可能将排放曲线与特定植物病原体联系起来。这项工作解决了目前需要转向一种既敏感又有选择性的技术，以确定在不同病原体负荷下排放的植物VOC的概况，同时仍然足够普遍，以检测所有可能排放的VOC（即不针对特定的VOC组成基于假定的植物疾病）。这项技术可能允许以非破坏性的方式，在真实的时间内识别广泛的植物病原体。因此，它对植物科学及其他领域的广泛生物学科产生了影响。理想情况下，由于使用相干光源的高度定向性，该仪器还能够监测田间的挥发性有机化合物分布，以定位作物内的受感染区域，确保对补救行动作出快速反应，从而最大限度地减少感染影响并减轻作物损失。