A genomics-assisted synthetic hexaploid wheat gene isolation and pre-breeding platform for improved heat tolerance and sustainable production

背景：小麦是人类直接消费的最重要的谷物，对受当前和预期的未来全球粮食安全失败影响最大的人群来说至关重要。印度是全球第二大小麦生产国，而英国目前是全球产量最高的国家之一。然而，相对狭窄的遗传基础目前阻碍了小麦的改良，因为它降低了我们培育适应不断变化的环境和疾病压力的新品种的能力。在印度，高温胁迫对小麦产量的负面影响越来越大，而在英国，由于干旱造成的损失每年损失6000万英磅。考虑到印度和欧洲西北部目前的气候变化情景，这两个国家的高温压力的危害将进一步恶化。这将对印度的小麦种植社区(其中大多数种植小麦供自己消费)以及英国的产量和全球粮食安全产生严重影响。全球对小麦的需求不断增加，再加上气候变化的影响和可持续小麦生产的必要性等因素，意味着对包含小麦遗传变异信息的育种方法(‘基因组辅助’方法)的投资现在被广泛接受为关键。然而，为了充分利用这些方法，必须首先识别和利用具有当前使用的品种中通常找不到的可取特性的新小麦品系。小麦的野生近亲拥有巨大的遗传多样性，但其中大部分没有得到充分利用。通过重建两个小麦祖先之间发生了1万年的原始自然杂交过程，可以将有用的遗传变异从祖先物种转移到优良小麦背景中，从而创造出现代面包小麦。这些新型小麦(称为合成六倍体小麦，SHW)为育种计划注入了新的遗传变异，旨在开发对环境胁迫和其他次优环境条件具有更强耐受性的新品种。项目目标和成果：该项目旨在创造新的SHW品系(使用专门选择的具有耐热应激能力的祖先品系)，并利用这些品系杂交到现代印度和英国品种，创造出1500个庞大的后代群体。这一群体将构成独特的小麦生物资源的基础，在此基础上，可以应用基因组辅助方法来研究通过SHW引入的耐热性的新遗传决定因素。这将通过以下方式实现：(1)识别和分型群体中存在的遗传变异。(2)使用新的方法对1,500个后代系在高温胁迫下的表现进行详细评估。(3)评估不同的基因和基因变体在热应激下是如何表达的。这些数据集将被分析，以确定源自SHW亲本品系的遗传区域，这些亲本品系赋予热应激耐受性。通过这种方式，该项目将同时识别标记提高耐热性的遗传标记，并提供表达有益性状的印度和英国适应的小麦品系。将利用项目伙伴在小麦研究和育种之间的独特地位，促进将项目成果迅速转化为国家小麦育种方案。该项目提供生物和遗传资源/工具，以及知识交流和能力建设计划，这将有助于印度和英国小麦研发和育种的进展。

Background: Wheat is the most important cereal for direct human consumption, and is crucial to populations most exposed to current and anticipated future failures in global food security. India is the world's second largest producer of wheat, while the UK is currently one of the world's highest yielding environments. However, a relatively narrow genetic base currently hampers wheat improvement by reducing our ability to breed new varieties adapted to changing environmental and disease pressures. In India, heat stress is having an increasingly negative impact on wheat yields, while in the UK losses due to drought loss cost >£60 million per year. The detrimental of heat stress in both countries is set to worsen, given current climate change scenarios for India and NW Europe. This will have serious impacts on India's wheat farming community (the majority of which grow wheat for their own consumption), as well as on UK production and global food security. Increasing global demand for wheat, coupled with factors such as the effects of climate change and the necessity for sustainable wheat production, means that investment in breeding approaches that incorporate information on wheat genetic variation ('genome-assisted' approaches) are now widely accepted as critical. However, to fully exploit such approaches, novel wheat lines which possess desirable traits not normally found in currently used varieties must first be identified and utilised. The wild relatives of wheat possess immense genetic diversity, but most of this is underutilized. Useful genetic variation can be transferred into elite wheat backgrounds from progenitor species by recreating the original natural hybridisation process that occurred 10,000 years between two wheat progenitors to create modern bread wheat. These novel wheats (called 'synthetic hexaploid wheat', SHW) inject novel genetic variation into breeding programmes aimed at developing new varieties with increased tolerance to environmental stress and other sub-optimal environmental conditions. Project aims and outcomes: This project aims to create novel SHW lines (using progenitor lines specifically selected to harbour heat stress tolerance), and use these to cross into modern Indian and UK varieties to create a large population of 1,500 progeny. This population will form the basis of a unique wheat biological resource upon which genomic-assisted approaches can be applied to investigate the novel genetic determinants of heat tolerance introduced via SHW. This will be achieved by:(1) Identifying and typing the genetic variants present in the population.(2) Using novel approaches to undertake detailed assessment of how each of the 1,500 progeny lines performs under heat stress. (3) Assessing how different genes and gene variants are expressed when exposed to heat stress. These datasets will be analysed to identify the genetic regions originating from the SHW parental lines that confer tolerance to heat stress. In this way, the project will simultaneously identify genetic markers that tag increased heat tolerance, as well as provide Indian- and UK-adapted wheat lines that express the beneficial traits. The unique position of the project partners at the interface between wheat research and breeding will be leveraged to promote rapid translation of project outcomes into national wheat breeding programmes. This project provides biological and genetic resources/tools alongside a programme of knowledge exchange and capacity building, which will aid the progress of wheat R&D and breeding in India and the UK.