21ENGBIO: Re-engineering amino acid metabolism in wheat grain

21ENGBIO：重新设计小麦籽粒中的氨基酸代谢

基本信息

批准号：
BB/W011999/1
负责人：
Nigel Halford
金额：
$ 12.74万
依托单位：
Rothamsted Research
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2022
资助国家：
英国
起止时间：
2022 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FW011999%2F1
关键词：
21ENGBIO Re engineering amino acid

项目摘要

Lysine is one of the 20 amino acids used to make proteins and most animals, including humans, cannot make it, so rely on acquiring it through their diet. Unfortunately, cereal grains contain low concentrations of lysine, resulting in nutrient deficiency in humans and farm animals, such as pigs and chickens, that are dependent on cereal grain for their nutrition. This has resulted in imported soybeans taking much of the market for pig and chicken feed manufacture in the UK and EU, while in developing countries, lysine deficiency is a major cause of malnutrition in people who are reliant on cereal grains for their protein intake. Lysine deficiency does not occur in people in developed countries because they can acquire lysine from meat, but the National Food Strategy (2021) considers current levels of meat consumption to be unsustainable. Reducing our dependence on meat for lysine intake will require the development of a sustainable and readily-available global supply of plant-sourced lysine, which will be unachievable without major changes to the structure of global agricultural production and agri-food systems, unless cereals can be re-engineered to accumulate higher concentrations of lysine in their grains. This project will use genome editing with CRISPR to produce high lysine, non-GM wheat lines. Lysine is synthesised from another amino acid, aspartate, via a multistep biochemical pathway. The key control point is a reaction catalysed by an enzyme called DHDPS. DHDPS is feedback-inhibited by lysine, which binds to the enzyme, and we will edit a wheat DHDPS gene so that the enzyme it encodes no longer binds lysine. We will do this in wheat that has already been edited and has high concentrations of aspartate in the grain, using selection agents that will enable us to identify plants containing a lysine-insensitive DHDPS. These agents include a lysine analogue that competes with lysine for incorporation into proteins, and compounds that inhibit DHDPS itself. These compounds will have to be synthesised and our team will include a synthetic chemist as well as plant molecular biologists and Rothamsted's Cereal Transformation Team, making it genuinely multidisciplinary. Crucially, the inhibitors bind DHDPS over the lysine binding site and we have designed changes that will not only render DHDPS lysine-insensitive but also make it resistant to the inhibitors. The stacking of multiple edits to re-engineer amino acid biosynthesis in wheat grain makes the project an excellent fit for the bioengineered cells and systems theme of the call. The editing will require a technique called homology-directed repair, a technology that has been applied successfully in barley and maize but has not yet been used successfully in wheat, so very much a breakthrough technology. Overall, the project is high risk but high gain, with huge potential international impact, in developed as well as developing countries, affecting human nutritional status, animal feed manufacture, bioethanol production through improved animal feed co-product, market expansion for UK wheat grain, and an increase in availability of plant-derived lysine.

赖氨酸是用于制造蛋白质和大多数动物（包括人类）的20种氨基酸之一，因此依赖于通过饮食来获取它。不幸的是，谷物谷物含有低浓度的赖氨酸，从而导致人类和农场动物（例如猪和鸡）的营养缺乏，这些动物取决于谷物的营养。这导致进口大豆在英国和欧盟采用了大部分市场的猪和鸡肉饲料制造商，而在发展中国家，赖氨酸不足是依靠谷物摄入蛋白质摄入的谷物的人营养不良的主要原因。发达国家的人们不会出现赖氨酸缺乏症，因为他们可以从肉中获取赖氨酸，但是国家食品战略（2021）认为当前的肉类消耗水平是不可持续的。减少我们对赖氨酸摄入的肉类的依赖将需要开发可持续且易于获取的全球植物赖氨酸的供应，除非可以重新工程重新工程以在其颗粒中累积高浓度的碱性。该项目将使用CRISPR的基因组编辑来生产高赖氨酸，非GM小麦系列。赖氨酸是通过多步生物化学途径从另一个氨基酸天冬氨酸合成的。关键控制点是由称为DHDP的酶催化的反应。 DHDP被赖氨酸抑制的反馈抑制，该赖氨酸与酶结合，我们将编辑小麦DHDPS基因，以使其编码的酶不再结合赖氨酸。我们将使用已经编辑并具有高浓度的天冬氨酸的小麦进行选择，使用的选择剂将使我们能够识别含有赖氨酸不敏感DHDP的植物。这些药物包括赖氨酸类似物，该赖氨酸与赖氨酸竞争以掺入蛋白质中，并抑制DHDPS本身的化合物。这些化合物必须合成，我们的团队将包括一名合成化学家以及植物分子生物学家和Rothamsted的谷物转型团队，使其真正具有多学科。至关重要的是，抑制剂在赖氨酸结合位点上结合了DHDP，我们设计了变化，不仅会使DHDPS赖氨酸不敏感，而且还使其对抑制剂具有抗性。在小麦谷物中重新设计的多个编辑以重新设计的氨基酸生物合成使该项目非常适合呼叫的生物工程细胞和系统主题。编辑将需要一种称为同源性维修的技术，该技术已成功地在大麦和玉米中应用，但尚未成功地用于小麦，因此非常突破性的技术。总体而言，该项目是高风险，但在发达国家和发展中国家中具有巨大的国际影响力，影响人类营养状况，动物饲料生产，通过改善动物饲料的氧化含量，英国小麦谷物的市场扩张以及植物衍生赖氨酸的可用性增加。