description
- Feeding the growing global population will require an increase in total food production of around 50% by 2050. Though yields of our major crops are increasing, current annual yield increases are insufficient to meet this demand. To produce enough food, we need to improve crop productivity, producing greater yields on a per-area basis. At the same time, the climate crisis brings unprecedented challenges for crop production, with adverse environmental conditions such as heat waves decimating harvests. We need crops that are more productive, whilst also being more resilient and yielding well under hostile environments. My research addresses these pressing needs to boost productivity and heat resilience by exploring the overlooked contribution of crop reproductive physiology. The flowers and grains of cereal plants, such as rice and wheat, are surrounded by specialised modified leaves called bracts. These bracts can help to cool the vulnerable flowers by evaporative cooling through microscopic pores called stomata. In leaves, by controlling gas exchange between the plant and its environment, stomata determine the rates of carbon dioxide uptake for photosynthesis, and also water vapour release for cooling. Bracts also photosynthesise, producing extra sugars to fill the grains, and in wheat we know that this can contribute 12-42% of total grain yields. The function of bracts and their stomata offers untapped potential for yield gains and protective cooling of the vulnerable flowers and developing grains. In this project I will explore the function of bract stomata in wheat to reveal this potential. Then, this knowledge can be transferred into rice. Unlike wheat, rice lacks outward-facing stomata on its bracts and has much lower rates of floral organ photosynthesis, suggesting an even higher yield gain potential. The project is divided into three core objectives, with high value deliverables. Objective 1 explores the function of wheat spike stomata in photosynthesis and cooling. By characterising the physiological consequences of different bract stomatal densities, in heat stressed and controlled field grown conditions, we can determine their contribution to crop yield. Lab work will also demonstrate the functional characteristics of these stomata. Objective 2 will determine how bract stomatal distributions are determined. Uncovering the gene regulatory networks that control bract stomatal development in wheat and rice will allow us to understand why their stomatal distributions differ and offer targets for further manipulations. Objective 3 will involve manipulating rice stomatal distributions to enhance panicle cooling and photosynthesis. Transferring targets from Objective 2 into rice will allow us to optimise stomatal distributions in this core crop and verify their effect on photosynthesis, cooling and yield to engineer crops for the coming climate crisis. With a rapidly increasing population, and a climate crisis endangering the global food supply, generating climate ready crops is essential. This project will offer new breeding targets for two of our core crops, wheat and rice, to allow us to increase yield by optimising bract photosynthesis. Furthermore, precision manipulations to bract stomatal distribution have the potential to protect flowers from high temperatures that devastate crop yields, increasing stress resilience.