The molecular basis of quantitative variation in photoperiod response

植物需要在成功授粉和种子发育的机会最高的时候开花。为了达到这个目的，大多数植物在一年中的特定时间开花。定时通常是通过使用来自环境的线索来实现的，特别是温度和白天的长度（光周期）。谷类作物利用这些线索，但它们利用这些线索的方式已经被驯化和植物育种所改变，以培育出在世界各地多样化的农业环境中表现良好的品种。我们知道，来自世界不同地区的小麦品种，甚至来自欧洲不同地区的小麦品种，对光周期的反应是不同的。我们最近通过识别一个关键基因，在了解它们是如何做到这一点上取得了突破。在这笔拨款中，我们将研究这种基因是如何工作的，以及DNA水平上的差异如何转化为整个植物生长方式的差异。光周期（Ppd）基因是伪反应调节基因家族的一员。在模式植物拟南芥（拟南芥）中，这些基因已被证明是生物钟的一部分，或与生物钟密切相关。生物钟是用来测量白天长度和控制植物大部分代谢的内部计时器。幸运的是，许多其他通过日照长度控制开花的基因（光周期途径）在不同的植物物种中都保存得很好。这意味着我们可以利用拟南芥的信息来确定小麦光周期途径的组成部分。通过研究光周期基因和光周期通路的其他组分，我们将能够了解小麦的光周期反应是如何改变的。面包小麦是一种六倍体植物，这意味着它是由三个二倍体祖先物种的基因组组成的自然杂交种。这三个基因组中的每一个都可以影响开花时间的变化，一个重要的问题是这三个基因组上的基因是如何整合和调控的。我们现在可以对植物进行异花授粉，以建立单、双、三种早花或晚花变种的组合。了解它们的行为将为小麦开花控制提供有价值的新见解，这将使植物育种者能够选择一系列适合不同环境的适应性。了解基因如何在组合中起作用也与小麦除开花外的其他性状相关。为了探索光周期基因如何工作的想法，我们将使用转化的大麦植物测试不同版本的基因。这提供了一个简单的测试系统来研究基因的哪些区域是最重要的。了解作物如何对日长等环境因素做出反应非常重要，因为这将使植物育种者能够根据特定环境定制品种，从而最大限度地提高产量。它还将帮助开发适应气候变化新条件的新品种。

Plants need to flower when the chances of successful pollination and seed development are highest. To achieve this, most plants flower at a specific time of year. Timing is often achieved by using cues from the environment, particularly temperature and day length (photoperiod). Cereal crops use these cues but the way they use them has been changed by domestication and plant breeding in order to develop varieties that perform well in the diverse farming environments that occur around the world. We know that wheat varieties from different parts of the World, and even from different parts of Europe, differ in how they respond to photoperiod. We have recently made a breakthrough in understanding how they do this by identifying a key gene. In this grant we will study how this gene works and how differences at the DNA level translate into differences in the way the whole plant grows. The photoperiod (Ppd) gene is a member of a family called the pseudo-response regulators. In the model plant Arabidopsis thaliana (thale cress) these genes have been show to be part of, or closely associated with, the circadian clock which is the internal time keeper that is used to measure day length and to control much of the plant's metabolism. Fortunately, many of the other genes that are used to control flowering by day length (the photoperiod pathway) are well conserved in different plant species. This means that we can use information from Arabidopsis to identify the components of the photoperiod pathway in wheat. By studying the photoperiod gene and the other components of the photoperiod pathway we will be able to understand how photoperiod response is altered in wheat. Bread wheat is a hexaploid plant, which means it is a natural hybrid comprising the genomes of three diploid ancestor species. Each of the three genomes can contribute flowering time variation and an important question is how the genes on the three genomes are integrated and regulated. We can now cross-pollinate plants to build up single, double and triple combinations of early or late flowering variants. Understanding how these behave will give valuable new insights into the control of flowering in wheat and this will allow plant breeders can select a range of adaptation suitable for diverse environments. Understanding how genes work in combination is also of relevance to other wheat traits apart from flowering. To explore ideas about how the photoperiod genes work we will test different versions of the genes using transformed barley plants. This provides a simple test system to investigate which regions of the gene are most important. Understanding how crops respond to environmental cues like day length is important because it will allow plant breeders to tailor varieties to particular environments and hence to maximize productivity. It will also assist the development of new varieties tailored to new conditions that are arising from climate change.