Understanding the molecular control of senescence and nutrient remobilisation in wheat

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Wheat is one of the world's most important crops providing over 20% of calories eaten by mankind. However, wheat not only provides calories, it is also a vital source of other nutrients including protein and minerals such as iron and zinc. Protein and mineral malnutrition affects over 30% of the world's population, so if we could improve the levels of nutrients in the grain of staple crops such as wheat, it could have a dramatic impact on the health and lives of people across the globe.The nutrient content of wheat grain is intimately linked to the controlled death (senescence) of the plant. There is an important trade-off between prolonging the life of the plant to maximise yield, and ensuring that nutrients are released from dying parts of the plant (e.g. leaves) to the grain. Scientists have often studied the senescence of leaves and grain development separately. I hypothesize that if we understand the integrated process from the dying leaves to the developing grain we will be able to improve the amount of nutrients entering the grain, without reducing yield. I propose to improve our understanding of nutrient movement from the leaves into the grain, and its relationship with senescence, in three main ways. Firstly I will study the genes involved in these processes in plants with normal and reduced ability to move nutrients into their grain. This will identify which genes are key control points. Secondly I will explore where genes known to be involved in nutrient movement and senescence are active in the plant and what their functions are. Thirdly I will identify mutant plants which have altered rates of senescence and identify which genes are changed in these plants, to understand the senescence process in more detail. Currently very few genes have been identified in wheat to be important in controlling senescence and nutrient content. This project will identify several of the most important genes representing a step change in understanding which genes control senescence and nutrient content in wheat. This information will be useful to crop breeders and biotechnologists to improve the nutrient content of wheat grain without reducing the yield.