Can urban air quality be improved through the use of plant associated bacteria?

项目要点：作为项目符号列表的3点-评估植物和微生物如何为提供城市地区的生态系统服务做出贡献，重点是缓解空气污染-调查植物相关微生物群对空气污染物的降解-使用环境基因组学方法表征叶圈微生物群概述：超过90%的英国人口是城市人口，因此面临一系列特定于城市的环境挑战(更高的温度、更高的洪水风险、更低的空气质量)。绿色基础设施可以帮助缓解其中的一些挑战，但种植的选择可能会对惠益的程度产生重大影响。具有某些结构和功能特性的植物(毛叶、大叶面积、高蒸腾速率)往往提供更高水平的服务。特别令人感兴趣的是与减轻空气污染有关的生态系统服务。空气污染导致数百万人过早死亡，是世界大都市地区的一个重要问题。空气污染物包括一些挥发性物质，如NOx、SO2、一氧化碳和一系列挥发性有机化合物。此外，颗粒物(PM)是空气质量和公众健康的主要问题。PM由自然和人为过程产生，后者包括交通排放。植被在维持和改善空气质量方面的作用是毋庸置疑的，但其潜在的机制目前还不完全清楚。一种这样的机制涉及捕获和去除大气中的污染物，如PM，但也为叶圈(植物的地面部分)中的植物相关微生物群落提供了一个栖息地；这些细菌也可以起到去除和代谢这些气态污染物的作用。在RHS和华威之前的研究基础上，我们热衷于测试植物和细菌对改善空气质量的潜力。植物捕获颗粒物的能力由于具有毛叶等特性而得到增强。被捕获的PM可能仍然与叶子结构结合在一起，或者被雨水冲刷掉而转移到土壤中。RHS的研究强调，像水苏和鼠尾草这样的毛叶植物有利于捕捉PM。栖息在植物地上部分的细菌，即所谓的叶圈，有可能降解大气中的挥发性化合物，并可能有助于降解挥发性污染物和与PM结合的化学品华威正在进行的研究表明，与树叶相关的微生物群落可以降解对硝基苯酚(PNP；Palmer，Bding，Schäfer，未发表)，这是一种主要的大气硝基酚4，是柴油发动机颗粒物5的一种成分。我们还观察到叶球微生物群能够降解一氧化碳。在这个博士项目中，你将讨论植物-细菌伙伴关系的基本方面，以及它们减轻空气污染物的潜力。需要解决的关键问题是叶毛的存在如何影响叶圈的微生物定殖化，以及微生物区系如何与植物和大气中的污染物相互作用。这将通过以前被确定为在绿色基础设施(Stachys和Salvia spp.)内提供高水平生态系统服务的植物来进行。有趣的是，这些植物还含有高含量的酚类化合物，这可能会影响叶圈的定植，但也会使微生物群降解植物和大气中的酚类化合物。适当的比较将与缺乏毛叶/酚类含量的“对照”植物进行。总体而言，学生将评估这些植物提供生态系统服务的程度是否可以通过与特定微生物合作降解空气污染物来增强。

Project Highlights: 3 points as a bulleted list- Assess how plants and microbes contribute to the provision of ecosystem services in urban areas, focussing on air pollution mitigation- Investigate degradation of air pollutants by plant-associated microbiota - Characterise phyllosphere microbiomes using environmental genomics approachesOverview: Over 90% of the UK population is urban and thus facing a range of urban-specific environmental challenges (higher temperatures, increased flooding risks, reduced air quality). Green infrastructure can help mitigate some of these challenges, but the choice of planting can have significant impact on the extent of benefits1. Plants with certain structural and functional properties (hairy leaves, large leaf areas, high transpiration rate) tend to provide higher level of services. Of particular interest are ecosystem services related to the mitigation of air pollution. Air pollution causes millions of premature deaths and is an important issue in metropolitan areas worldwide2. Air pollutants include a number of volatile species, such as NOx, SO2, carbon monoxide and a range of volatile organic compounds. In addition, particulate matter (PM) is a major concern for air quality and public health. PM are produced from natural and anthropogenic processes, the latter including transport emissions.The role of vegetation in maintaining and improving air quality is undisputed, but the underlying mechanisms are not fully understood at present. One such mechanism involves the trapping and removal of pollutants from the atmosphere, such as PM, but also in providing a habitat for plant associated microbial communities in the phyllosphere (above ground parts of plants); these bacteria too can act to remove and metabolise some of these gaseous pollutants. Building on previous research at RHS and Warwick, we are keen to test the potential of plants and bacteria to contribute to air quality improvement. The ability of plants to trap particulate matter is enhanced by properties such as having hairy leaves3. Trapped PM may remain bound to the leaf structure or can be transferred into soil by being washed off by rain water. Research at RHS has highlighted hairy-leaved plants like Stachys and Salvia species to be beneficial for PM trapping.Bacteria inhabiting the above ground parts of plants, the so-called phyllosphere, have the potential to degrade atmospheric volatile compounds and may contribute to degradation of volatile pollutants and chemicals bound to PM. Ongoing research at Warwick has shown microbial communities associated with tree leaves to degrade para-nitrophenol (PNP; Palmer, Bending, Schäfer, unpublished), a dominant atmospheric nitrophenol4, which is a component of particulate matter from diesel engines5. We have also observed phyllosphere microbiota to be capable of carbon monoxide degradation. In this PhD project you will address fundamental aspects of plant-bacterial partnerships and their potential to mitigate air pollutants. Key questions to be addressed are how the presence of leaf hairs affects microbial colonisation of the phyllosphere and how the microbiota interacts with the plant and atmospherically derived pollutants. This will be carried out with plants previously identified as providing a high level of ecosystem services within green infrastructure (Stachys and Salvia spp.). Interestingly, these plants also have high content of phenolic compounds, which may affect colonisation of the phyllosphere, but also prime the microbiota to degrade plant and atmosphere derived phenolic compounds. Suitable comparisons will be done with 'control' plants lacking hairy leaves/phenolic content. Overall, the student will assess whether the extent of ecosystem services delivery by these plants can be enhanced through the air pollutant degradation via partnership with specific microorganisms.