Improving germination performance through a mechanistic understanding of seed priming

通过对种子引发的机械理解提高发芽性能

• 批准号: BB/S002081/1
• 负责人: Christopher West
• 金额: $ 56.79万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FS002081%2F1
• 关键词: Improving; germination; performance; through; mechanistic

The project will address the important agricultural issue of improving seed germination, in particular in seeds that are pre-treated to enhance germination processes. Seeds underpin sustainable agriculture and food security, providing the majority of global food principally as cereals and legumes. Seeds also play essential roles in crop propagation, and optimal yields require high vigour seed lots that provide rapid, uniform germination and seedling establishment that is tolerant of stress conditions. Germination and seedling establishment are routinely improved in commercial species by pre-treatment of seeds prior to germination. This process, termed priming, involves controlled hydration to activate pre-germinative processes without completion of germination. However, the molecular basis of priming, and the associated loss of seed longevity in primed seeds, is not well understood to-date, but cellular repair processes are likely to have key roles.In this project, we will uncover the molecular mechanisms which confer vigour enhancement in priming, and establish the genetic basis for the associated loss of seed longevity. This builds on our recent discovery that the mechanisms that mediate responses to DNA damage in plants control germination. In dry seeds there is a steady accumulation of background DNA damage which is exacerbated by adverse conditions during seed maturation, storage and germination. This leads to extremely high levels of genome stress experienced by the embryo upon seed rehydration. High levels of DNA repair activity are required early in germination to reverse this damage before growth resumes, as failure in repair processes results in severe mutagenesis of genetic material, impaired development and ultimately death of the plant. Sensing of DNA damage leads to rapid activation of cellular signalling programmes early in germination that function to delay germination, allowing extended time for repair, or activate cell death. As priming functions to reverse this delay to germination, we hypothesise a central role for DNA repair and damage signalling processes in the priming mechanism. Here we will use genetic, biochemical and high throughput analytical approaches to reveal the molecular link between genome integrity and priming, establishing the mechanistic basis of seed priming for the enhancement of seed germination.Primed seeds display reduced storability, resulting in substantial yield economic losses for the seed industry. The underlying causes of this reduced longevity is unknown. However, we recently identified that seeds defective in the repair of chromosomal breaks display highly reduced longevity after priming. This important new result reveals a novel link between increased DNA damage in primed seeds with the accelerated loss of germination potential. We will build on these results to reveal the molecular basis for the reduced longevity of primed seeds, identifying the requirement for specific repair activities that mitigate reduced shelf-life post-priming. Furthermore, identifying the signalling responses associated with reduced longevity provides a powerful approach to reveal the underlying cellular causes of the short lifespan of primed seeds.The ultimate aim of this project is to develop novel lines of plants with improved longevity after priming through modulating the activity of these DNA repair factors. We will test the potential of key factors to genetically improve the resilience of seed germination in Arabidopsis and Brassica oleracea, a crop species important to UK agriculture. These approaches will address the long-standing problem that seeds of many vegetable species suffer from poor germination and establishment after storage, resulting in reduced crop yields. Taken together, the project will enable the application of technologies based on our knowledge of plant stress responses to deliver high quality seeds and support sustainable agriculture.

该项目将解决提高种子发芽率这一重要的农业问题，特别是提高经过预处理以促进发芽过程的种子的发芽率。种子是可持续农业和粮食安全的基础，提供了全球大部分粮食，主要是谷物和豆类。种子在作物繁殖中也起着重要作用，最佳产量需要高活力的种子批次，这些种子批次提供快速、均匀的发芽和耐胁迫条件的幼苗建立。在商业物种中，通常通过在发芽前对种子进行预处理来改善发芽和幼苗建立。这个过程，称为引发，涉及受控的水合作用，以激活发芽前的过程，而不完成发芽。然而，引发的分子基础，并在引发种子寿命的损失，是不是很清楚的日期，但细胞修复过程可能有关键作用，在这个项目中，我们将揭示分子机制，赋予活力增强引发，并建立相关的种子寿命损失的遗传基础。这建立在我们最近发现的基础上，即介导植物对DNA损伤的反应的机制控制发芽。在干种子中，存在背景DNA损伤的稳定积累，其在种子成熟、储存和萌发期间因不利条件而加剧。这导致种子再水化后胚胎经历极高水平的基因组应激。在萌发早期需要高水平的DNA修复活性，以在生长恢复之前逆转这种损伤，因为修复过程的失败导致遗传物质的严重诱变，发育受损并最终导致植物死亡。DNA损伤的感知导致萌发早期细胞信号程序的快速激活，其功能是延迟萌发，允许延长修复时间或激活细胞死亡。作为启动功能，以扭转这种延迟发芽，我们假设在启动机制中的DNA修复和损伤信号传导过程的核心作用。本研究将利用遗传学、生物化学和高通量分析方法，揭示基因组完整性与引发之间的分子联系，建立种子引发提高种子萌发的机制基础。引发后的种子耐贮性降低，给种子产业带来巨大的产量和经济损失。寿命缩短的根本原因尚不清楚。然而，我们最近发现，在修复染色体断裂缺陷的种子显示引发后寿命大大减少。这一重要的新结果揭示了引发种子中DNA损伤增加与发芽潜力加速丧失之间的新联系。我们将在这些结果的基础上揭示引发种子寿命缩短的分子基础，确定减轻引发后货架期缩短的特定修复活动的要求。此外，识别与寿命降低相关的信号反应提供了一个强有力的方法来揭示引发种子寿命短的潜在细胞原因。本项目的最终目的是通过调节这些DNA修复因子的活性来开发引发后寿命提高的新植物品系。我们将测试关键因素的潜力，以遗传方式提高拟南芥和甘蓝种子萌发的弹性，这是一种对英国农业很重要的作物。这些方法将解决长期存在的问题，即许多蔬菜品种的种子在储存后发芽和定植不良，导致作物产量下降。总之，该项目将使基于我们对植物胁迫反应的知识的技术应用能够提供高质量的种子并支持可持续农业。

项目成果

Genome damage accumulated in seed ageing leads to plant genome instability and growth inhibition.

• DOI: 10.1042/bcj20230006
• 发表时间: 2023-04-12
• 期刊: The Biochemical journal

Seed DNA damage responses promote germination and growth in Arabidopsis thaliana.

• DOI: 10.1073/pnas.2202172119
• 发表时间: 2022-07-26
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1

WHIRLY protein functions in plants

• DOI: 10.1002/fes3.379
• 发表时间: 2022-03
• 期刊: Food and Energy Security
• 影响因子: 5
• 作者: Rachel E. Taylor;C. E. West;C. Foyer