The role of circadian oscillators in temperature responses of wheat

由于气候变化，我们需要了解作物对温度反应的基本生物学。韦伯实验室帮助发现，温度反应的一个调节器是生物钟，它控制植物中事件的时间。我们在模式植物拟南芥和英国主要农作物小麦中发现了昼夜节律的差异。差异在于一种名为早花3(ELF3)的蛋白质，它可能会影响生物钟和温度反应。在拟南芥中，ELF3与LUX ARRHYTHMO(LUX)结合，LUX是一种调节基因的DNA结合蛋白。ELF3-LUX还与ELF4结合，形成晚上的蛋白质复合体，通过ELF3中对温度敏感的Pron样结构域来调节生物钟和温度响应。在较高的温度下，ELF3会凝结，不能结合LUX。我们发现小麦ELF3不太可能结合LUX，因为它们是在不同的时间产生的，LUX在黄昏和ELF3在黎明。小麦ELF3可能对温度敏感没有贡献，因为它缺乏温度敏感结构域。这些差异意味着，不可能将拟南芥的知识转移到小麦上来预测生物钟如何工作，也不可能预测小麦生长如何受到温度的调节。我们将描述小麦生物钟的结构以及它如何影响温度反应，为育种人员提供有关基因功能的信息，以确定在不断变化的气候中改良小麦的目标。为了了解小麦的生物钟，我们将建立一个基于基因活动时间的数学模型。我们将根据描述不同温度下丰度时钟分量的数据来模拟温度对昼夜节律时钟的影响。通过实验检验小麦昼夜节律数学模型的预测，可以充分了解温度对小麦昼夜节律的影响。如果我们发现模型和数据之间存在偏差，模型将被改进以纳入新的信息。改进后的模型将被用来设计实验，告知温度周期如何设置小麦生物钟的时间。我们将进行一系列实验来了解小麦ELF3是否具有与拟南芥相似或不同的功能：我们将测量具有和不具有ELF3功能的小麦植株中的基因活性，以发现ELF3是否像在拟南芥中那样调控基因表达，以及类似的基因是否受到调控；我们将发现小麦ELF3蛋白在缺乏ELF3功能的拟南芥中是否能够完成拟南芥蛋白的功能；我们将确定小麦ELF3是否与LUX形成蛋白质复合体，并发现小麦ELF3蛋白的功能和溶解性是否受温度的影响。韦伯发现，由于生物钟的作用，对冷压力的反应取决于一天中的不同时间。我们将调查小麦中是否也存在这种情况，以确定生物钟基因是否可能成为培育对变化环境中预期的极端胁迫的耐受性的有用靶标。最后，我们将通过将昼夜节律的数学模型与小麦的每日生长联系起来，试图了解小麦昼夜节律对温度敏感生长的贡献有多大。我们已经组建了一支由昼夜节律、数学建模和基因组分析方面的多技能专家团队，以实现对小麦生长的温度重置和温度调节过程中发生的机制的理解。我们将以开放的格式共享数学模型和数据，以允许从事小麦生物学其他方面工作的人员使用这些信息，并将这些模型纳入更大的小麦生长模型。其目标是提供基本的生物学知识，可用于开发改良小麦品种。

Due to climate change we need to understand the basic biology of temperature responses of crop plants. The Webb lab contributed to the discovery that one regulator of temperature responses is the circadian clock, which controls the timing of events in plants. We have found differences between the circadian clocks in the model plant Arabidopsis and wheat, the UK's major crop. The differences are in a protein called EARLY FLOWERING 3 (ELF3), which might affect the circadian clock and temperature responses. In Arabidopsis, ELF3 binds LUX ARRHYTHMO (LUX), a DNA binding protein that regulates genes. ELF3-LUX are also bound by ELF4 to form an evening complex of proteins to regulate the circadian clock and temperature responses due to temperature-sensitive prion-like domains in ELF3. At higher temperatures ELF3 condensates and cannot bind LUX. We have found wheat ELF3 is unlikely to bind LUX because they are made at different times, LUX at dusk and ELF3 at dawn. Wheat ELF3 might not contribute to temperature sensing because it lacks temperature-sensitive domains. These differences mean that it is not possible to transfer knowledge from Arabidopsis to wheat to predict how the circadian clock functions, nor how wheat growth is regulated by temperature. We will describe the structure of the wheat circadian clock and how it contributes to temperature responses to provide information about gene function for breeders to identify targets for improved wheat in a changing climate. To understand the wheat circadian clock, we will make a mathematical model based on the timing of gene activity. We will model temperature effects on the circadian clock from data describing the abundance clock components at different temperatures. A full understanding of the effect of temperature on the wheat circadian clock will be achieved by testing the predictions of the mathematical models of the wheat circadian clock by experimentation. If we find deviation between the models and the data, the model will be refined to incorporate new information. The refined model will be used to design experiments that inform how temperature cycles set the timing of the circadian clock in wheat. We will perform a number of experiments to understand if wheat ELF3 has similar or different function to Arabidopsis: we will measure gene activity in wheat plants with and without functional ELF3 to discover whether ELF3 regulates gene expression as it does in Arabidopsis, and if similar genes are regulated; we will discover if wheat ELF3 protein can fulfill the functions of the Arabidopsis protein in Arabidopsis lacking functional ELF3; we will determine if wheat ELF3 forms a protein complex with LUX and discover if wheat ELF3 protein function and solubility are affected by temperature. Webb contributed to the discovery that responses to cold stress depends on the time of the day due to the circadian clock. We will investigate if that is also the case in wheat to determine if circadian clock genes might be useful targets for breeding tolerance to the extreme stresses expected in the changed environment. Lastly, we will attempt understanding how much the wheat circadian clock contributes to thermosensitive growth by connecting our mathematical model of the circadian clock with the daily growth of wheat. We have put together a multi-skilled team of experts in circadian rhythms, mathematical modelling and analysis of genomes to achieve an understanding of the mechanisms that occur during temperature resetting of the clock and temperature regulation of wheat growth. We will share the mathematical models and data in open formats to allow those working on other aspects of wheat biology to use the information and incorporate the models into larger models of wheat growth. The goal is to provide basic biological understanding that can be used to develop improved wheat varieties.