Defining the genetic basis of barley metabolite content to improve nutrient use efficiency, crop quality and resilience with reduced inputs

大麦是一种非常重要的作物，无论是用于著名的苏格兰威士忌行业的春季麦芽大麦，还是用于动物饲料的冬季大麦。只有来自有限品种的优质大麦才会被用于麦芽和蒸馏，因此极大地影响了市场价值。大麦被认为是一种高投入的谷类食品，因此对威士忌和啤酒的总体碳足迹有很大贡献。在制麦过程中，适宜的氮(N)水平可促进粗粮中淀粉的酶促分解为糖。目前的解决方案是增加氮肥，以提高产量和保证质量。然而，生产氮肥的能源成本和土壤中不平衡的氮循环会以NOx的形式产生温室气体排放，这是造成不利环境足迹的主要原因。改善氮的回收和利用将减少对投入的需求，并减少污染(绿色复苏的关键)。博士学位的目的将是评估和改善我们对大麦高氮素利用效率和光合作用能力的遗传和代谢基础的理解，同时生产高蒸馏质量的谷物。大麦质量的关键是在一系列条件下保持碳同化和出口到发展中谷物的能力。这需要不断的新陈代谢调整，以应对环境的变化。培育具有新陈代谢能力的大麦的第一步将是确定支持新陈代谢优化的遗传结构。另一个目标是将对新陈代谢弹性的理解与关键的产量和品质性状联系起来。为了实现这一目标，将在减少氮素投入和使用替代化肥(例如市政堆肥、酿酒厂副产品)的情况下，对大麦种群进行高光合作用和高效粮食进口的筛选。这些数据将用于全基因组关联研究，以确定数量性状基因座(QTL)和在不同氮素条件下导致这些性状变异的候选基因。此外，还将确定这些氮素处理对代谢组的影响。然后，可以使用实验室规模的微型麦芽、糖化、发酵和蒸馏来生产烈酒，并评估其对酒精产量和风味特征的影响。了解支撑这些性状的遗传学和生理学将提供知识，以及遗传和代谢QTL，以帮助育种朝着减少投入和环境足迹的方向发展。该项目提供优秀的跨学科培训，发展植物生长和表型、基因组学、代谢组学、风味化学和感官分析以及统计分析和建模方面的技能。

Barley is a crop of great importance with respect to both spring malting barley for the renowned Scotch whisky industry, and winter barley for animal feeds. Only high-quality barley from a limited number of varieties is taken forward to malting and distilling, therefore greatly influencing market value. Barley is regarded as a high-input cereal and therefore contributes significantly to the overall carbon footprint of whiskies and beers. Optimum nitrogen (N) levels promote the enzymatic breakdown of starch in raw grains to sugars during malting. The current solution is the addition of N fertilisers which enhance yield and assure quality. However, the energy costs of producing N fertiliser and an unbalanced N cycle in soils which produces ghg emissions in the form NOx contribute most to the unfavourable environmental footprint. Improving N recovery and utilisation will reduce the need for inputs and reduce pollution (key to the green recovery). The aim of the PhD will be to assess and improve our understanding of the genetic and metabolic basis of high nitrogen use efficiency and photosynthetic capacity in barley, whilst producing grains with high distilling quality. Key to barley quality is the capacity to maintain carbon assimilation and export to developing grains under a range of conditions. This requires constant metabolic adjustment in response to environmental variation. A first step towards breeding metabolically resilient barley will be to define the genetic architecture underpinning the optimisation of metabolism. A further objective is to link an understanding of metabolic resilience to key yield and quality traits. To achieve this, barley populations will be screened for high photosynthetic rates and efficient grain import, under reduced N inputs and with alternative fertilisers (e.g. municipal compost, distillery co- products). This data will be used in a genome wide association study (GWAS) to identify Quantitative Trait Loci (QTL) and candidate genes contributing to variation in these traits under different nitrogen conditions. Additionally, the impact of these nitrogen treatments on the metabolome will be determined. Laboratory scale micro-malting, mashing, fermentation and distillation can then be used to produce spirit and assess the impact on alcohol yield and flavour profile. Understanding the genetics and physiology underpinning these traits will provide knowledge, and genetic and metabolic QTL, to aid breeding towards reduced inputs and environmental footprint. The project offers excellent interdisciplinary training, developing skills in plant growth and phenotyping, genomics, metabolomics, flavour chemistry, and sensory analysis, as well as statistical analysis and modelling.