Exploiting seed coat properties to improve uniformity and resilience in Brassica seed vigour

利用种皮特性提高芸苔属种子活力的均匀性和弹性

• 批准号: BB/M017869/1
• 负责人: Steven Penfield
• 金额: $ 55.41万
• 依托单位: John Innes Centre
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FM017869%2F1
• 关键词: Exploiting; seed; coat; properties; improve

A key current goal in plant breeding is to introduce traits that add resilience to climate change. Growers and seed raisers frequently report to the levy board that they have problems with poor or unpredictable germination, even of expensive seed. Seed vigour is determined by the genetics of the crop, by vigour-enhancing formulations applied during seed processing and crucially, by the temperature during seed production. Our evidence suggests that seed traits are the most temperature sensitive in plants, with temperature changes of 1C during seed set capable of making important changes to seed performance. Large seed companies produce seed at specific locations where environment is suited for maximising vigour, but there is still variation from site to site and stochastic temperature fluctuations that affect quality. Increases in weather and climate variation mean that we need to develop the ability to uncouple seed vigour from temperature influences during seed production. This proposal describes a project for breeding new varieties of Brassica with high seed vigour insensitive to the effects of temperature during seed production. Our work has shown that during seed set temperature is sensed by the mother plant and controls progeny seed germination by varying the development and composition of the seed coat. If we alter seed coat development or metabolism genetically, germination remains high regardless of seed set temperature. These processes are widely conserved among all angiosperms, including Brassicas and other vegetable seeds. Mutagenised populations are important breeding tools in horticulture and have been used historically for novel trait discovery. Here we describe the application of modern state-of-the-art post-genomic technologies to conduct screens of a new mutant B. oleracea population to identify and characterise genes affecting seed coat properties and therefore vigour resilience. We aim to isolate seed coat mutants using simple screens, and using new bioinformatic techniques already available at JIC we can quickly identify causative genes by genome re-sequencing. Using this same population we can also isolate Brassica mutants in specific genes of interest by a process known as TILLING. We know which genes are most important because of extensive work in our lab and others in the closely-related model species Arabidopsis. In this way we can quickly identify Brassica lines in which seed coats and seed vigour resilience are altered compared to laboratory and commercial varieties.Seed companies also enhance seed vigour by applying chemical formulations in coating to the outside of seeds during processing. These formulations can also include pesticides and fungicides. However, seeds are highly discriminating and uptake of applied chemicals can be as low as 5%, leading to widespread contamination of the environment. If the industry is to continue to benefit from the effects of commercial seed formulations is it clear that uptake into seeds must be improved to minimise the environment impacts of the technology. However, currently there are no techniques available for quantitatively monitoring chemical uptake efficiency into seeds without adding fluorescent labels that also change their properties. A side effect of our seed coat engineering approach is that seed coats control both vigour and permeability to chemicals. Therefore the second part of this proposal is to development an exciting new microscopic technique which can follow the uptake of unlabelled chemicals quantitatively, spatially and in real time into plant tissues, and which also can be used to look inside intact whole seeds (Figure 3). In this way we will be able to see what types of chemical are taken up efficiently into seeds and how this can be altered using genetics. The resulting approach can be used to prioritise development of new chemicals and to show whether more seed permeability can be exploited to maximise chemical uptake.

目前植物育种的一个关键目标是引入增加气候变化适应力的性状。种植者和种子饲养者经常向征税委员会报告，他们有发芽不良或不可预测的问题，即使是昂贵的种子。种子活力取决于作物的遗传学、种子加工过程中使用的活力增强制剂以及关键的种子生产过程中的温度。我们的证据表明，种子性状是最敏感的温度在植物中，与温度变化的1C在种子能够使种子性能的重要变化。大型种子公司在特定的地点生产种子，这些地点的环境适合最大限度地提高活力，但不同地点之间仍然存在差异，温度的随机波动也会影响质量。天气和气候变化的增加意味着我们需要发展在种子生产过程中将种子活力与温度影响分开的能力。本文介绍了一个选育对温度不敏感的高活力芸苔属新品种的计划。我们的研究表明，在种子结实过程中，温度被母体植物感知，并通过改变种皮的发育和组成来控制后代种子的萌发。如果我们改变种皮的发育或遗传代谢，发芽率仍然很高，无论种子设置温度。这些过程在所有被子植物中广泛保存，包括油菜和其他蔬菜种子。诱变群体是园艺学中重要的育种工具，历史上一直用于新性状的发现。在这里，我们描述了现代国家的最先进的后基因组技术的应用进行筛选的一个新的突变体B。甘蓝种群，以确定和检测影响种皮特性的基因，从而活力的弹性。我们的目标是使用简单的筛选分离种皮突变体，并使用JIC已经提供的新生物信息学技术，我们可以通过基因组重新测序快速识别致病基因。使用相同的群体，我们还可以通过称为TILLING的过程分离感兴趣的特定基因中的芸苔属突变体。我们知道哪些基因是最重要的，因为我们的实验室和其他人在密切相关的模式物种拟南芥中进行了大量的工作。通过这种方式，我们可以快速识别出与实验室和商业品种相比，种皮和种子活力弹性发生变化的芸苔属品系。种子公司还通过在加工过程中将化学制剂涂覆在种子外部来提高种子活力。这些制剂还可以包括杀虫剂和杀真菌剂。然而，种子具有高度的鉴别力，所施用化学品的吸收率可低至5%，导致环境的广泛污染。如果该行业要继续受益于商业种子制剂的影响，显然必须提高种子的吸收，以尽量减少该技术对环境的影响。然而，目前还没有技术可用于定量监测化学吸收效率的种子，而不添加荧光标记，也改变了他们的属性。我们的种皮工程方法的一个副作用是种皮控制活力和对化学物质的渗透性。因此，该提案的第二部分是开发一种令人兴奋的新的显微技术，该技术可以定量地、空间地和真实的时间地跟踪未标记的化学物质进入植物组织的吸收，并且还可以用于观察完整的整个种子的内部（图3）。通过这种方式，我们将能够看到哪些类型的化学物质被有效地吸收到种子中，以及如何使用遗传学来改变这一点。由此产生的方法可用于优先开发新化学品，并显示是否可以利用更多的种子渗透性来最大限度地提高化学品的吸收。