Chemical manipulation and mechanisms of weed seed persistance, dormancy release and germination

任何农业实践的一个不可否认的和昂贵的问题是杂草对这些农业系统的适应。气候变化进一步加剧了这一问题，杂草很快适应环境变化，包括热应激。只有将农作物收成损失降至最低，才能实现为养活世界不断增长的人口所必需的粮食生产的可持续集约化。目前，约有10%的作物产量因杂草而损失，如果不使用除草剂，这种损失将远远大于杂草。然而，除草剂技术的持续有效性受到对除草剂具有抗性的杂草生物型的快速发展的威胁。抗性杂草现在是大多数化学类别除草剂的问题，也是所有主要种植区域的问题。因此，杂草控制是全球粮食安全的一个主要问题，特别是考虑到自1980年代以来没有新的除草剂作用模式被商业化。新的杂草控制工具是迫切需要的，特别是在英国，欧盟/英国的法规已经导致我们的“作物保护工具箱”（“健康收获”倡议，英国全国农民联盟）收缩。欧洲的作物保护投资从20世纪80年代占全球投资的33.3%下降到今天的7.7%。迫切需要开发新的活性物质，这些活性物质对健康食品的生产是有效的和环境安全的。这对食品质量和防止食品价格进一步上涨也很重要，最近英国消费者受到的影响比欧洲大陆更大。有效控制杂草的问题在一年生大田作物系统中最为严重，一年生杂草与作物幼苗同时出现。这些问题杂草的成功至少部分归功于形成了庞大而持久的土壤种子库。本申请的前提是，可以在化合物中发现新颖且有效的杂草控制工具，所述化合物1）促进杂草种子在土壤库中的协调萌发和/或2）在未萌发或非常早期萌发阶段杀死杂草种子的“杀种子剂”中。在前一种情况下，可以在常规除草剂（或替代的非化学策略）之前施用促发芽化合物，以实现对总杂草种子种群的更有效控制，而“杀种子剂”可以在作物已经出现之后施用，以限制迟生杂草的出现。目前，虽然已知一些发芽刺激剂，但没有一种是商业化的，也没有任何商业除草剂故意靶向种子特异性过程。所有传统的除草剂都以杂草幼苗生长为目标。因此，通过对杂草种子萌发、存活和持久性过程的深入了解，开发新型杂草控制解决方案的潜力相当大。该项目建立了伦敦皇家霍洛威大学G Leubner教授的种子生物学小组与先正达国际研究中心Jealott's Hill的杂草控制研究生物学之间的合作。我们计划调查所描述的问题与几个代表性的问题杂草，首先模拟他们的发芽反应范围很广的环境温度，然后通过选择关键的温度来调查潜在的激素变化和分子机制，没有和应用已知的化合物打破休眠，诱导种子发芽。所获得的知识将用于选择化合物库和筛选新的化学物质，其具有促进杂草种子的协调萌发和/或作为“杀种子剂”的潜力。这将有可能确定有助于下游研究的新型作用模式，以用新型化学品填充我们的“作物保护工具箱”。我们的项目将产生知识，以指导开发新的战略，通过耗尽种子库来控制杂草。

An undeniable and expensive problem of any agricultural practice is the adaptation of weeds to these agricultural systems. This problem is further amplified by climate change, weeds adapt very quickly to environmental change including heat stress. The sustainable intensification of food production necessary to feed the world's growing population will only be achievable if crop harvest losses can be minimised. About 10% of crop production is currently lost to weeds and this loss would be far greater without the use of herbicides. However, the continued effectiveness of herbicide technology is threatened by the rapid advance of weed biotypes that are resistant to herbicides. Resistant weeds are now a problem across most chemical classes of herbicide and also across all the major cropping regions. Thus weed control represents a major concern for global food security, especially given that no new herbicide modes of action have been commercialized since the 1980s. New weed control tools are urgently required especially in the UK where EU/UK regulations have caused shrinkage in our 'crop protection toolbox' ("Healthy Harvest" initiative, UK National Farmers Union). Investment in crop protection in Europe has fallen from 33.3% of worldwide investment in the 1980s to 7.7% today. There is an urgent need for the development of new active substances which are effective and environmentally safe for the production of healthy food. This is also important for food quality and for preventing further food price rises which have recently affected UK consumers more than those in the mainland Europe.The problem of effective weed control is most severe in annual field crop systems and with annual weeds which emerge at the same time as the crop seedlings. These problem weeds owe their success, at least in part, to the formation of large and persistent soil seed banks. The premise of the current application is that novel and effective weed control tools might be found in compounds that either 1) promote the coordinated germination of weed seeds in the soil bank and/or 2) in 'seedicides' that kill weed seeds at the ungerminated or a very early germination stage. In the former case, germination-promoting compounds might be applied prior to conventional herbicides (or alternative non-chemical strategies) to achieve more effective control of the total weed seed population while 'seedicides' might be applied after crops have emerged in order to limit late weed emergence. Currently, while some germination stimulants are known, none are commercial and neither do any commercial herbicides deliberately target seed-specific processes. All classical herbicides target processes of growing weed seedlings. Thus there is considerable potential for novel weed control solutions through engaging a deeper understanding of the processes of weed seed germination, survival and persistence.This project establishes a collaboration between the Seed Biology Group of Prof G Leubner at Royal Holloway University of London and Weed Control Research Biology at Syngenta's International Research Centre Jealott's Hill. We plan to investigate the described issues with several representative problem weeds by first modelling their germination responses to a wide range in ambient temperatures, and then by choosing key temperatures to investigate the underlying hormonal changes and molecular mechanisms without and with the application of compounds known to break dormancy and induce germination of seeds. The obtained knowledge will be used to select compound libraries and screen for novel chemicals which have the potential to either promote the coordinated germination of weed seeds and/or to act as 'seedicides'. This will potentially identify novel modes of action instrumental for downstream research to fill our 'crop protection toolbox' with novel chemicals. Our project will generate knowledge to guide the development of novel strategies to control weeds by depleting the seed bank.