Understanding and exploiting a nitrogen-fixing endophyte for enhancing sustainability and productivity of vertical farming

英国进口40%的水果和蔬菜，这些供应链受到产区天气和地缘政治问题的影响，农产品短缺在英国变得越来越普遍。以可持续的方式增加英国产量对于为英国水果和蔬菜供应提供弹性至关重要。垂直农业是一个快速增长的部门，提供可靠的全年生产，以提高生产力，在非农业土地上生产，化学投入（化肥/农药）最少，没有径流污染和高效用水。垂直农业的受控条件最大限度地提高了生长（最大限度地缩短了收获时间），并防止了浪费（不利的气候）。然而，英国生产PACE园艺食品的一个关键挑战是高能源成本和相关的温室气体排放。在不增加生产的环境负担的情况下，大幅度提高这些作物的产量和/或减少收获天数，是确保稳定和可持续供应的唯一解决办法。我们的项目旨在提高资源利用效率-提高生产力，同时降低每公斤产品的成本和温室气体排放。氮的可用性是作物产量的限制因素，但即使在受控环境农业中，肥料的使用也会显著增加温室气体排放。在这里，我们研究了一种能够从空气中固定氮的内生细菌，并利用这种内生细菌来提高垂直农业的资源利用效率。重氮营养葡糖酸醋杆菌首先从甘蔗中鉴定出来，并且能够定殖于许多不同的作物。它通过两种主要机制刺激植物生长：固氮，为植物细胞提供氨;分泌植物激素和小分子，诱导根系结构的变化，从而提高养分利用效率。甘蔗G.固氮菌能提供植物所需的大部分氮素，G.重氮营养菌处理可以使马铃薯产量在田间增加高达30%。然而，我们知道，不同品种的作物在G。固氮菌定殖和生长反应，以及G.莴苣是在英国种植的最有价值的叶菜，并且越来越多的生产比例是通过受控环境农业。在这个项目中，我们将使用生菜多样性集的定量遗传学和转录组分析来确定决定生菜定殖和/或对G.氮营养型我们将研究G.固氮菌对产量/收获天数的影响、内生固氮菌对莴苣氮含量的贡献以及固氮作用对根系变化的相对重要性。我们将量化G.重氮营养型细菌定殖生菜时，在商业规模的垂直农业系统，并确定G。我们的提案解决了PACE的三个挑战领域（作物遗传改良以提高产量，减少环境影响并实现可持续发展目标，以及通过设计更好的系统可持续地提高产量，质量和生产力）。项目成果将可持续地提高垂直农业系统中的生菜产量，并在整个生菜CEA供应链中带来环境和经济效益。结果将推动育种和/或选择生菜品种，以提高资源利用效率，通过G。固氮菌定殖;为垂直未来客户优化种植配方和技术;以及Azotic产品的新市场。

The UK imports 40% of its fruit and vegetables with these supply chains subject to disruption through weather in production areas and geopolitical issues, with shortages of produce becoming more common in the UK. Increasing UK production in a sustainable manner is critical to provide resilience to UK fruit and vegetable supply. Vertical farming is a rapidly-growing sector offering reliable year-round production for increased productivity, production on non-agricultural land with minimal chemical inputs (fertilizer/pesticides), no run-off pollution and highly-efficient water use. The controlled conditions of vertical farming maximise growth (minimising time-to-harvest) and prevent waste (from unfavourable climate). However, a key challenge to UK production of PACE horticulture edibles is the high energy cost and associated GHG emissions. Significant increases in the yield of these crops and/or reduction in days-to-harvest, without increasing the environmental burden of production, is the only solution to ensure a stable and sustainable supply. Our project is aimed at increasing resource use efficiency - enhancing productivity whilst reducing costs and GHG emissions per kg of produce.Availability of nitrogen is a limiting factor for crop yield, but fertilizer use contributes significantly to GHG emissions, even in controlled environment agriculture. Here, we investigate an endophytic bacterium that is able to fix nitrogen from the air and exploit this endophyte to enhance resource use efficiency of vertical farming. Gluconacetobacter diazotrophicus was first identified from sugarcane and able to colonise many different crops. It stimulates plant growth via two main mechanisms; nitrogen fixation that provides ammonia to plant cells; and secretion of phytohormones and small molecules that induce changes in root system architecture, resulting in enhanced nutrient use efficiency. It is clear that in sugarcane G. diazotrophicus can provide a significant proportion of the nitrogen required by the plant and G. diazotrophicus treatment can increase potato yield by up to 30% in the field. However, we know that different varieties of crops vary in G. diazotrophicus colonisation and growth response, and the impact of G. diazotrophicus colonization has not been tested in vertical farming systems.Lettuce is the most valuable leafy vegetable grown in the UK and an increasing proportion of production is via controlled environment agriculture. In this project we will use quantitative genetics and transcriptome profiling of a lettuce diversity set to identify genetic loci and candidate mechanisms determining lettuce colonisation and/or response to G. diazotrophicus. We will investigate the impact of G. diazotrophicus on yield/days to harvest, the contribution of endophyte nitrogen-fixation to lettuce nitrogen content and the relative importance of nitrogen fixation versus root system changes. We will quantify the effects of G. diazotrophicus colonization on lettuce when grown in a commercial-scale vertical farming system and determine the impacts of G. diazotrophicus on GHG emissions and economics of lettuce production in a vertical farm.Our proposal addresses three of the PACE challenge areas (Genetic improvement of crops for increased yield, Reducing environmental impacts and progressing towards sustainability targets, and Sustainably increasing yield, quality and productivity by designing better systems). Project outcomes will sustainably enhance lettuce production in vertical farming systems with environmental and economic benefits across the lettuce CEA supply chain. Outcomes will drive breeding and/or selecting lettuce varieties for enhanced resource use efficiency via G. diazotrophicus colonisation; optimised growing recipes and technology for Vertical Future clients; and new markets for Azotic products.