Super-Rice: a UK-China Collaboration to Improve Rice Nitrogen Use Efficiency (NUE)

预计到2050年，世界粮食需求将翻一番。满足这一需求是一项重大的全球挑战，需要以最低的环境成本提高作物产量。当今高产的“绿色革命作物品种”(GRV)在使用氮肥方面效率低下，这种低效对农民来说代价高昂，并对环境造成破坏。世界需要既高产又能提高氮素利用效率的新作物。我们的项目融合了英国和中国独特的专业知识来改良水稻NUE。它保留了当前水稻GRV的突出特点，并将其转化为高产、提高氮效率的超级稻品种。我们将采用一种开创性的方法，将天然遗传变异的发现与标记辅助育种和‘基因组编辑’相结合，创造出在减少氮肥投入的情况下将获得高产的超级稻。首先，WPs1-3利用各种遗传、基因组和生物信息学技术来发现能够增加水稻GRV的NUE的单个遗传变异。WP1在田间发现了增加NUE的变异基因的分子同一性。WP2专注于发育调节基因的变体，这些基因在控制植物的生长和新陈代谢方面发挥着至关重要的作用。利用这种监管变异是有重要先例的，因为最初的GRV本身就是通过使用这种变异创建的。WP3的重点是发现能够增加水稻转运蛋白活性的变异体，使水稻能够从土壤中提取氮。然而，在WPs1-3中发现的变异可能来自野生或其他水稻品系，而这些品系本身并不是GRV。因此，WPs1-3重要的是使用新的基因组编辑技术来专门确定这些新的变种是否会增加GRV遗传背景中的NUE。基因组编辑可以精确地改变基因组序列，从而使我们能够编辑特定的GRV基因序列(将它们改变为新发现的变异形式)。然后，将在低氮土壤中测量这些基因组编辑的GRV的产量，从而告诉我们新发现的突变体是否确实可以增加GRV的NUE。接下来，WP4进一步利用基因组编辑的能力来同时编辑多个基因组位置。这使得将多个变种组合(‘堆叠’)引入一辆GRV成为可能。变异组合可能会产生至少是相加的(单个变异效应的简单总和)和可能是协同的(大于单个变异的简单总和效应的增加)的NUE增加。因此，在WP4中，我们将把多个选定的变种组合(‘堆叠’)成超级稻的基因型，然后确定这些超级稻在低氮土壤中的产量。我们的基因组编辑的超级稻将不包含任何‘外来’转基因，因此可能比转基因‘转基因’品种更容易获得农业用途的监管批准。然而，由于全面采用超级稻需要公众普遍接受，我们还将率先使用基因组编辑的超级稻，以提高传统标记辅助超级稻育种的效率、重点和速度。基因组编辑的超级稻将指导植物育种者开发(非基因组编辑的)超级稻，这种超级稻将使用天然水稻变体育成，将被公众接受，因为它既不是转基因水稻，也不是基因组编辑的水稻。促进双边英国-中国水稻研究关系是我们提案的另一个主要目标。我们建立并维持现有的合作伙伴关系(XF和NPH；XF和QQ)，并从新的合作伙伴关系(NPH和QQ)中获得附加值。总而言之，我们建议英国和中国建立跨国合作伙伴关系，培育公众可以接受的强化纽埃超级稻，提高中国和世界农业的可持续性，并在2050年及以后帮助养活世界。

World food demand is predicted to double by 2050. Meeting this demand is a major global challenge, and requires increased crop yields at minimal environmental cost. Present-day high-yielding 'green revolution crop varieties' (GRVs) are inefficient in their use of nitrogen (N) fertiliser, an inefficiency that is costly to the farmer and damaging to the environment. The world needs new crops that are both higher yielding and have increased N use efficiency (NUE). Our project fuses distinct UK/China expertise to improve rice NUE. It retains the outstanding features of current rice GRVs, and transforms them into Super-Rice varieties that are high yielding and have enhanced NUE. Using a pioneering approach combining the discovery of natural genetic variants with marker-assisted breeding and 'genome editing', we will create Super-Rice that will be high-yielding when grown with reduced N fertiliser inputs.First, WPs1-3 exploit a variety of genetic, genomic and bioinformatics techniques to discover individual genetic variants that increase the NUE of rice GRVs. WP1 discovers the molecular identities of variant genes increasing NUE in the field. WP2 focusses on variants of the developmental regulatory genes that play overarching roles in controlling the growth and metabolism of plants. There is important precedent for exploiting such regulatory variation, because the initial GRVs themselves were created by use of such variants. WP3 focusses on the discovery of variants increasing the activity of the transporters that enable rice to extract N from the soil. However, the variants discovered in WPs1-3 may come from wild or other strains of rice that are not themselves GRVs. WPs1-3 therefore importantly use the new technique of genome-editing to specifically determine if these new variants increase NUE in GRV genetic backgrounds. Genome-editing enables precise alteration of genome sequence, thus enabling us to edit specific GRV gene sequences (change them into the newly discovered variant form). The yield of these genome-edited GRVs will then be measured in low-N soils, thus telling us if the newly discovered variant can indeed increase the NUE of the GRV.Next, WP4 further exploits the ability of genome editing to simultaneously edit more than one genomic location. This enables the combined ('stacked') introduction of multiple variants into one GRV. It is possible that variant combinations will generate NUE increases that are at least additive (a simple sum of individual variant effects) and that may be synergistic (increases that are greater than the simple sum effects of individual variants). Thus, in WP4, we will combine ('stack') multiple selected variants into Super-Rice genotypes, and then determine the yields of these Super-Rice genotypes in low-N soils.Our genome-edited Super-Rice will not contain any 'foreign' transgenes, and may therefore more readily receive regulatory approval for agricultural use than will transgenic 'GM' varieties. However, because full adoption of Super-Rice requires general public acceptance, we will also pioneer the use of genome-edited Super-Rice to enhance the efficiency, focus and speed of conventional marker-assisted breeding of Super-Rice. Genome-edited Super-Rice will guide plant breeders in the development of (non-genome-edited) Super-Rice that will be bred using natural rice variants and that will be publicly acceptable because it is neither GM nor genome-edited.The promotion of bilateral UK-China rice research relationships is another major objective of our proposal. We build upon and sustain pre-existing partnerships (XF and NPH; XF and QQ), and derive added value from a new one (NPH and QQ). In summary, we propose a transnational UK-China partnership that will breed publicly acceptable enhanced-NUE Super-Rice that will enhance the sustainability of Chinese and world agriculture and help feed the world in the years leading up to 2050 and beyond.