Understanding how the natural environment influences DMSP production by plants

二甲基磺基丙酸酯（DMSP）是生物和环境中含量丰富的重要化合物，在营养循环、胁迫耐受性中起着关键作用，也是气候活性气体二甲基硫（DMS）的主要前体。一些植物产生DMSP，例如米草属，它可能是盐沼环境中的主要DMSP生产者-全球DMSP/DMS生产热点。事实上，DMSP生产被认为允许植物忍受与在海岸生长相关的条件。目前，已知很少有植物产生DMSP，并且DMSP的确切作用是未知的-这是迄今为止没有描述植物DMSP合成基因的结果。在我们鉴定和批准植物DMSP合成基因的基础上，学生将研究植物如何以及为什么产生DMSP。我们的工作将对更好地评估植物对全球DMS和DMSP生产的贡献产生重要的影响。评估植物在自然环境中产生DMSP/DMS目前还不清楚植物何时何地产生DMSP/DMS。因此，学生将评估从诺福克盐沼取样的大米草中的DMSP水平，使用已建立的GC和LCMS技术在一年的季节中测量不同组织（根，叶，茎，花序）中的DMSP。学生还将比较不同的地点，以评估高沼泽和低沼泽环境中植物的产量和DMSP/DMS通量。评估在受控环境下生长的植物中DMSP的产生为了验证我们的假设，即植物产生DMSP以耐受环境胁迫，学生将在受控实验室条件下在存在/不存在不同胁迫的情况下种植模型物种，并评估植物生长（例如鲜/干重，根长）并使用GC测量DMSP水平。学生将首先关注盐和渗透胁迫，因为我们相信这些是控制S.英国国教。氮和硫的影响也将被探索，因为这些对于调节微生物DMSP的产生很重要，因此在植物中也很重要。确定控制DMSP产生的环境因素我们已经确定了S. anglica和学生将使用qRT-PCR测量目标1中收集的样品中这些的表达。还将在目标2的样品中测量基因表达，以确定非生物胁迫如何调节DMSP的产生。另外，将使用已建立的体外测定法研究酶功能，以测量DMSP合成速率。学生将使用现有的基因组/转录组数据集进行生物信息学分析，以评估DMSP合成基因的分布。根据这些预测，将从自然环境中对各种植物进行取样，并评估DMSP的生产情况。这项工作将包括其他盐沼植物、模式物种和作物，并将确定植物DMSP生产的规模和多样性。学生将参与项目的各个方面，包括实验设计，数据收集，分析和管理。该项目将为他们提供极好的独立机会，并在环境过程前沿研究的各个方面接受广泛的培训。

Dimethylsulfoniopropionate (DMSP) is an abundant and important compound in biology and the environment, where it has key roles in nutrient cycling, stress tolerance and as the major precursor to the climate-active gas dimethyl sulfide (DMS). Some plants produce DMSP, e.g. Spartina, which is likely the major DMSP producer in saltmarsh environments - global hotspots for DMSP/DMS production. Indeed, DMSP production is thought to allow plants to tolerate conditions associated with growing at the coast. Currently, few plants are known to make DMSP and the precise role of DMSP is unknown - a consequence of no plant DMSP synthesis genes having hitherto been described. Building on our identification and ratification of plant DMSP synthesis genes, the student will study how and why plants produce DMSP. Our work will have important consequences for better evaluating plant contributions to global DMS and DMSP production in the natural environment.Objectives:1. Evaluate plant production of DMSP/DMS in the natural environmentIt is currently unclear when and where plants produce DMSP/DMS. The student will therefore assess DMSP levels in Spartina anglica sampled from Norfolk saltmarshes, measuring DMSP in different tissues (roots, leaves, stems, inflorescence) over an annual season using established GC and LCMS techniques. The student will also compare different sites to assess production and DMSP/DMS flux in plants from high- and low-marsh environments.2. Assess DMSP production in plants grown under controlled environmentsTo test our hypothesis that plants produce DMSP to tolerate environmental stress, the student will grow model species under controlled lab conditions in the presence/absence of different stresses and assess plant growth (e.g. fresh/dry weight, root length) and measure DMSP levels using GC. The student will initially focus on salt and osmotic stress, as we believe these are the most important stresses governing DMSP production in S. anglica. The effects of nitrogen and sulfur will also be explored, as these are important for regulating microbial DMSP production and thus likely important in plants too.3. Determine environmental factors that govern DMSP productionWe have identified candidate DMSP synthesis genes in S. anglica and the student will measure expression of these in the samples collected in Objective 1 using qRT-PCR. Gene expression will also be measured in samples from Objective 2 to determine how abiotic stress regulates DMSP production. Enzyme function will additionally be studied using established in vitro assays to measure DMSP synthesis rates.4. Establish how widespread DMSP production is in plantsThe student will perform bioinformatics analyses using existing genomic/transcriptomic datasets to assess distribution of DMSP synthesis genes. Based on these predictions, diverse plants will be sampled from their natural environments and assessed for DMSP production. This work will include other saltmarsh plants, model species and crops, and will determine the scale and diversity of plant DMSP production. The student will be involved in all aspects of the project including experimental design, data collection, analysis and management. This project will give them excellent opportunities for independence and to receive a broad training in diverse aspects of cutting-edge research on environmental processes.