Developing rice resources for resilience to climate change and mitigation of carbon emissions

与全球变暖有关的气候变化对我们生产足够的粮食、能源和水以满足不断增长的人口需求的能力构成威胁。人类活动增加了大气中温室气体等致暖物质的含量，从而推动了全球变暖的上升趋势。随着全球气温上升，干旱和洪水等恶劣天气的发生率增加，这可能导致作物产量损失。水稻是世界上种植的主要主食作物之一，是许多人的主要食物和生计来源，特别是在热带地区。全世界每年生产700多亿吨稻草，其中大部分在田地里燃烧，为下一季作物让路。这会向大气中释放大量的黑碳和对流层臭氧，对空气质量、人类健康（呼吸道疾病）、作物产量和全球变暖产生负面影响。这项研究的主要目的之一是帮助稻草摆脱废物，并将其作为一种宝贵的资源广泛利用。稻草主要由木质纤维素结构细胞壁组成，为生长的植物提供支持。木质纤维素是一种坚固耐用的纤维复合材料，由结构多糖（糖的聚合物）网络组成。这些多糖是潜在的丰富的糖来源，可以作为营养丰富的动物饲料，或用作发酵原料，以生产生物燃料或其他有价值的化学品和聚合物，可以取代石油衍生物。不幸的是，木质纤维素中的多糖很难消化成用于动物营养或发酵的糖，部分原因是它们被密封在一种叫做木质素的高抗性多酚中，部分原因是它们是部分结晶的，这两者都阻碍了消化酶的进入。在稻草中，这种情况由于大量（高达10%干重）二氧化硅的存在而进一步恶化，这使得它对大多数动物来说是不好吃的，并且还排除了在生物质炉中使用稻草来发电，因为它导致锅炉严重结渣。该项目汇集了五个世界级实验室的专业知识，以解决世界主要粮食作物的环境复原力和碳足迹的复杂问题。我们将使用最先进的植物基因组方法来确定秸秆消化率，木质纤维素成分和二氧化硅含量的自然变异的遗传基础，发现在菲律宾和越南收集的水稻的大多样性集合。我们将在这些多样性集合中采用全基因组关联扫描，以确定这些植物基因组区域中DNA序列差异与消化率，组成和二氧化硅含量变化之间的关联。这将确定分子标记，可以作为改进秸秆质量的代理，并允许使用快速标记辅助育种方法。同样的方法也将使我们能够识别对水稻中这些性状有强烈影响的基因。我们还将确定影响水稻作物应对干旱能力的基因组区域（气候变化带来的重大问题）我们的工作将确定现有的水稻品种低硅或高消化秸秆，我们将利用这些来研究和证明使用更好的质量秸秆作为动物饲料和生物燃料的优势生产我们将利用研究结果提醒农民和其他利益相关者在这些应用中使用稻草的潜在好处，以提高农民收入，当地生计和空气质量，并帮助减轻人类活动对全球变暖的破坏性影响。

Climate change associated with global warming poses a threat to our ability to produce sufficient food, energy and water to meet the demands of the growing human population. Human activity is helping to drive the upward trend in global warming by increasing the levels of warming agents such as greenhouse gases in the atmosphere. Episodes of severe weather, such as drought and flooding, increase as global temperatures rise, and this can lead to losses in crop yield. Rice is one of the main staple crops grown in the world and represents a major source of food and livelihood for many people, particularly in the tropics. Every year more than 700,000 million tons of rice straw is produced in the world and much of this is burned in the field in order to make way for the next season's crop. This releases large amounts s of black carbon and tropospheric ozone into the atmosphere with negative consequences for air quality, human health (respiratory illnesses), crop yield and global warming. One of the main aims of the proposed research is to help move rice straw away from being a waste product and toward its widespread utilisation as a valuable resource. Rice straw is primarily composed of lignocellulosic structural cell walls that provide support to the growing plant. Lignocellulose is a strong and resistant fibre composite material composed of a network of structural polysaccharides (polymers of sugars). These polysaccharides are potentially a rich source of sugars that could serve as nutritious animal feed, or be used as feedstock for fermentation to produce biofuels or other valuable chemicals and polymers that can replace those derived from petroleum. Unfortunately, the polysaccharides in lignocellulose are difficult to digest into sugars for animal nutrition or fermentation partly because they are sealed in a highly resistant polyphenol called lignin, and partly because they are partially crystalline, both of which block access to digestive enzymes. In rice straw, this situation is further exacerbated by the presence of large amounts (up to 10% dry weight) of silica, which makes it unpalatable to most animals and also precludes the use of rice straw in biomass furnaces to make electricity as it causes severe slagging of boilers. This project brings together the expertise of five world class laboratories to tackle the complex problem of environmental resilience and carbon footprint in a world staple food crop. We will use cutting edge plant genomic approaches to identify the genetic basis of natural variation in straw digestibility, lignocellulose composition and silica content found in large diversity collections of rice collected in the Philippines and Vietnam. We will employ genome wide association scans in these diversity collections to identify associations in the variation of digestibility, composition and silica content with differences in the sequences of DNA in regions of the genomes of these plants. This will identify molecular markers that can serve as proxies for improved straw quality and allow rapid marker assisted breeding approaches to be used. The same methods will also allow us to identify the genes that have strong influence on these traits in rice. We will also identify regions of the genome influencing the ability of rice crops to deal with drought (a major problem resulting from climate change) and produce molecular markers for improved drought tolerance.Our work will identify existing rice varieties with low silica or highly digestible straw and we will use these to investigate and demonstrate the advantages of using straw with better quality for applications as animal feed and for biofuel production. We will use the results from our research to alert farmers and other stakeholders to the potential benefits of using rice straw in these applications to improve farmer income, local livelihoods and air quality as well as helping mitigate the damaging effects of human activity on global warming.