Optimising the development of the energy grass Miscanthus through manipulation of flowering time

为了应对气候变化，有必要减少能源的使用，用可再生能源更多地替代我们使用的能源。此外，中国对进口化石燃料的过度依赖，使未来的燃料安全面临风险。存在许多可再生能源（例如，生物质能，风能，太阳能，海洋），人们普遍预测，在未来没有一种形式将占主导地位，换句话说，将有一个混合能源经济。来自能源作物的生物质是可再生能源结构的重要组成部分，因为除了能够通过燃烧提供电力和热量外，生物质还可以用来制造石油替代品，如液体运输燃料和平台化学品。芒草是一种多年生草本植物，也是一种理想的能源作物，因为它结合了热带草（如甘蔗）的快速生长速度，以及对英国温度的耐受性。此外，它是一种非常“环保”的作物，因为它只在最初的种植过程中需要除草剂处理，每年产生高产量的生物质，并对以前的营养生长产生“复利”，并且在年底高效的养分循环减少了种植和肥料投入。但由于芒草是一种新型作物，以往的基础研究非常有限，对其生长发育的调控知之甚少。该提案试图通过研究开花的分子基础来解决这一缺陷。为了帮助实现这一目标，我们将利用为拟南芥、水稻和玉米等模式生物开发的技术和开花知识。之所以选择开花，是因为它被认为是最有可能的特征，当优化时，在芒草中可以快速最大化产量。例如，植物尽可能晚开花以增加生长季节的长度，因此光合作用时间更长以产生更多生物量是非常可取的。然而，开花也会引发衰老，这是一个关键的过程，通过这个过程，氮和其他资源被动员到根茎，即植物在地下的部分。这一点非常重要，因为一些植物成分，主要是钾和氯化物，在燃烧时具有腐蚀性或形成腐蚀性化合物，并对发电设备造成损坏。商业种植的芒草品种（Miscanthus x giganteus）是两种芒草（Miscanthus sacchariflorus）和芒草（Miscanthus sinensis）自然产生的杂交品种。然而，亲本植物的开花控制似乎不同，因此在日照不足12小时时，芒草会开花，而在充足的温暖天气下，芒草会开花。杂交种在英国的条件下很少开花，而且是不育的。因此，在本项目中，我们的目标是确定最有可能参与Miscanthus x giganteus两个亲本开花时间的基因。模式生物的研究已经发现了40多个与开花时间有关的基因，在芒草中也将发现和测试同等作用的基因。这将有助于开发基于dna的开花分子标记，可用于英国芒草育种计划。分子标记的使用将有助于优化和预测年轻植物的开花时间，而不是等待三年的植物成熟。这也将有助于新杂交亲本的选择。从该项目中获得的信息将有助于更快地提高芒草的生物量产量。因此，这将意味着更多的碳将被固定在更小的土地面积上，此外还将改善农业经济，减少其他形式的土地使用压力，增加英国的燃料安全，最重要的是减少全球二氧化碳排放。

To combat climate change, it is necessary to use less energy and replace more of the energy we use with renewable sources. Furthermore, there is an over dependence on imported fossil fuels, putting future fuel security at risk. A number of renewable energy sources exist (for example, biomass, wind, solar, marine) and it is widely predicted that in the future no one form will dominate, in other words there will be a mixed energy economy. Biomass from energy crops are an important part of the renewable energy mix because in addition to being able to provide electricity and heat through combustion, biomass can be used to make petroleum replacements such as liquid transport fuels and platform chemicals. Miscanthus is a perennial grass and an ideal energy crop because it combines the fast growth rate of a tropical grass, such as sugarcane, with a tolerance to grow at UK temperatures. Furthermore it is a very 'eco-friendly' crop since it requires herbicide treatment only during initial establishment, produces a high yield of biomass annually with 'compound interest' on previous vegetative growth, and highly effective nutrient recycling at the end of the year reduces cultivation and fertiliser inputs. However as Miscanthus is a new crop, previous basic research has been extremely limited so that little is known about the regulation of growth and development. This proposal seeks to start addressing this deficit by investigating the molecular basis of flowering. To help in this we will exploit technologies developed for, and knowledge of flowering in, model organisms such as Arabidopsis thaliana, rice and maize. Flowering has been chosen because it is the characteristic identified as most likely, when optimised, to maximise yield quickly in Miscanthus. For example it is highly desirable for plants to flower as late as possible to increase the length of the growing season and therefore photosynthesise for longer to produce more biomass. However flowering is also desirable to trigger senescence which is a critical process by which nitrogen and other resources are mobilised to the rhizome, the part of the plant below ground. This can be very important because some plant constituents, principally potassium and chloride are corrosive or form corrosive compounds when combusted and cause damage to energy generation equipment. The commercially grown variety of Miscanthus (Miscanthus x giganteus), is a naturally occurring hybrid between two species, Miscanthus sacchariflorus and Miscanthus sinensis. However flowering appears to be controlled differently in the parent species so that Miscanthus sacchariflorus flowers when the daylength is less than 12 hours but Miscanthus sinensis flowers when sufficient warm days have been experienced. The hybrid only very rarely flowers under UK conditions and is sterile. Therefore in this project we aim to identify the genes most likely to be involved in flowering time in the two parents of Miscanthus x giganteus. Research on model organisms has identified over 40 genes implicated in flowering time and the equivalent genes in Miscanthus will be identified and tested for an equivalent role. This will enable the development of DNA-based molecular markers for flowering which can be used in the UK Miscanthus breeding programme. Use of molecular markers will help with the optimisation and prediction of flowering time in young plants rather than having to wait three years for plants to gain maturity. It will also help in the selection of parent plants for new crosses. The information gained from this project will help to increase biomass yields in Miscanthus more quickly. This will therefore mean that more carbon will be fixed in a smaller area of land, and in addition improve farm economics, decrease pressure on other forms of land use, increase UK fuel security and most importantly reduce global carbon dioxide emissions.