description
- 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.