Synchronization of crop seed germination

为了确保后代的生存，许多生物采用了一种下注对冲策略，即产生大量具有不同行为特征的后代。这种方法确保了它们的后代的一个子集无论在它们的环境中出现意外的波动都能存活下来。植物的种子萌发也遵循这种下注对冲策略。虽然种子能抵抗恶劣的环境条件，但幼苗却不能，这使得正确的发芽时间对植物未来的生存至关重要。植物已经进化出产生噪音的机制，在它们生产的单个种子中创造可变的行为，以改变它们对环境的发芽反应的时间。通过这种方式，无论未来的气候条件如何，它们的后代中至少有一部分得以生存。虽然这是植物在自然生态环境中生存的一个强大的适应特征，但种子的不同步发芽对农业来说是一个障碍。绝大多数粮食生产都是从播种开始的，在田间迅速而均匀地育苗是决定未来产量的关键因素。不均匀发芽会在田间留下空隙，增加除草剂的使用，而不同步的作物发育会降低单次机械收割后的产量。在每年520亿英镑的全球种子贸易中，强劲和同步的发芽支撑着高质量种子的销售。气候变化和多变的天气进一步加剧了一致性问题，这一问题将继续存在。该项目旨在揭示模型和作物种子中变异产生和对冲的机制基础，并利用这些信息来同步种子种群的萌发。这将通过互利的互动与工业合作伙伴Rijk Zwaan一起完成。我们之前已经开发了一个强大的预测数学模型，可以捕捉到种子中决定发芽时间的激素之间的关系。使用该模型，可以准确预测优先使用交替温度来促进种子萌发（Topham et al. 2017， PNAS）。该项目将扩展该模型的使用，以确定导致在单个种子中产生可变发芽控制激素丰度的机制。通过确定个体种子内的变异是如何产生的，将利用有针对性的策略来减轻这些产生噪声的机制，以协调种子种群的激素含量，进而协调种子种群的萌发。最初的概念验证研究将在模式物种拟南芥中进行，并将与Rijk Zwaan一起扩展到存在发芽同步农艺学限制问题的作物物种莴苣。在项目结束时，将对同一种质进行改良，以增强其萌发剖面的同步性。该项目的第二个方面涉及开发一个重要的高通量发芽监测系统。基因在单个种子中的表达可以动态监测，并用于预测早期事件后的未来发芽时间。通过这种方法，可以量化种子群体的变异性，并且该系统可以用于筛选具有相似发芽特性的种子。这代表了一种强大的科学工具和农业技术，可以产生具有同步发芽行为的种群。该项目将解决与变异性和风险对冲相关的关键科学问题，这些问题也与现代粮食生产系统和工业有着直接和强大的相关性。根据最先进的建模和生物学方法以及工业伙伴关系，将提供提高作物种子发芽同步的战略和种质的发展。

In order to ensure the survival of their offspring, many organisms employ a bet-hedging strategy whereby they produce a large number of progeny having different behavioural characteristics. This approach ensures that a subset of their progeny survive regardless of unexpected fluctuations in their environment. Seed germination in plants also follows this bet-hedging strategy. While seeds are resistant to harsh environmental conditions, seedlings are not, and this makes the correct timing of germination critical for the future survival of plants. Plants have evolved noise-generating mechanisms to create variable behaviour within the individual seeds they produce in order to alter the timing of their germination responses to the environment. In this way at least a fraction of their progeny are ensured survival regardless of future climatic conditions.While this is a powerful adaptive trait for the survival of plants in natural ecological settings, the asynchronous germination of seeds represents an obstacle to agriculture. The vast majority of food production begins with the planting of a seed, and the rapid and uniform establishment of seedlings in the field is key determinant of future yield. Non-uniform germination leaves gaps in the field which increases herbicide use, and asynchronous crop development lowers yield following single-pass mechanical harvesting. Robust and synchronous germination underpins the sale of high quality seed in the £52 billion annual global seed trade. Climate change and variable weather further exacerbates uniformity issues, which continue to persist.This project seeks to uncover the mechanistic basis of variability generation and bet hedging in model and crop seeds, and to leverage this information to synchronise the germination of seed populations. This will be done together with industrial partner Rijk Zwaan through a mutually beneficial interaction.We have previously developed a powerful predictive mathematical model that captures the relationships between hormones in seeds which determine when they germinate. Using this model, the preferential use of alternating temperatures to promote seed germination was accurately predicted (Topham et al. 2017, PNAS). This project will extend the use of this model to identify mechanisms that lead to the creation of variable germination-controlling hormone abundance in individual seeds. By identifying how variability in generated within individual seeds, targeted strategies to mitigate these noise-generating mechanisms will be utilized in order to harmonize the hormone content, and in turn germination, of seed populations. Initial proof of concept studies will be performed in the model species Arabidopsis, and together with Rijk Zwaan this will be extended to the crop species lettuce where agronomically limiting issues in germination synchronization are present. By the conclusion of the project this same germplasm will be modified to have enhanced synchronization in their germination profile.A second aspect to this project involves the development of a vital high throughput germination monitoring system. The expression of genes in individual seeds can be monitored dynamically, and used to predict the future timing of germination following early events. In this way the variability in seed populations can be quantified, and this system can be used to sort seeds having similar germination characteristics. This represents both a powerful scientific tool and agricultural technology to generate populations with synchronized germination behaviour.This project will address a key scientific questions relating to variability and bet hedging which also have a direct and powerful relevance to modern food production systems and industry. Following state of the art modelling and biological approaches and an industrial partnership, the development of strategies and germplasm enhancing the synchronization of crop seed germination will be provided.