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，需要以最小的环境成本提高作物产量。目前的高产“绿色革命作物品种”（grv）在使用氮肥方面效率低下，这种效率低下对农民来说代价高昂，而且对环境造成破坏。世界需要产量更高、氮素利用效率更高的新作物。我们的项目融合了英中两国独特的专业知识，以提高水稻氮肥利用率。它保留了现有水稻grv的突出特征，并将其转化为高产和提高氮肥利用率的超级稻品种。我们将采用一种开创性的方法，将自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种植的高产超级稻。首先，WPs1-3利用各种遗传、基因组和生物信息学技术来发现增加水稻grv氮肥利用率的个体遗传变异。WP1在田间发现了增加NUE的变异基因的分子特性。WP2关注的是发育调控基因的变异，这些基因在控制植物的生长和代谢中起着重要作用。利用这种调控变异有重要的先例，因为最初的grv本身就是通过使用这种变异而产生的。WP3的重点是发现增加转运体活性的变异，这些转运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本身不是grv的水稻品系。因此，WPs1-3重要地使用了基因组编辑的新技术来明确确定这些新变体是否增加了GRV遗传背景下的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（将其改变为新发现的变体形式）。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变异是否确实可以增加GRV的氮肥利用率。接下来，WP4进一步利用基因组编辑的能力，同时编辑多个基因组位置。这使得将多个变体组合（“堆叠”）引入一个GRV成为可能。变体组合可能会产生至少是可加性（单个变体效应的简单总和）和可能是协同性（大于单个变体的简单总和效应的增加）的NUE增加。因此，在WP4中，我们将把多个选择的变异组合（“堆叠”）成超级稻基因型，然后确定这些超级稻基因型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的普遍接受，我们还将率先使用基因组编辑的超级稻，以提高超级稻传统标记辅助育种的效率、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种进行培育，并且将被公众接受，因为它既不是转基因，也不是基因组编辑。促进中英双边水稻研究关系是我们提案的另一个主要目标。我们建立和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，我们建议建立中英跨国合作伙伴关系，培育出公众可接受的增强型nue超级稻，这将提高中国和世界农业的可持续性，并在2050年及以后的几年里帮助养活世界。

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.