Enhancing leaf transient carbon stores - role of fumarate as a possible storage compound

点击翻译按钮获取中文摘要

Human society finds itself facing a great challenge. Populations around the world have grown massively over the last century and are set to continue growing well into the next. Rising standards of living in countries like China and India and increases in production of biofuels are further increasing demand. This growing demand, combined with crop failures possibly linked to global climate change, have resulted in food prices rising substantially in recent years. It is estimated that food production needs to increase by 50% by the middle of this century to keep pace with demand.Photosynthesis is the process by which plants absorb light and use the energy to make sugars. This process forms the basis of life on this planet - all the food we eat originally comes from photosynthesis. An obvious way to increase the productivity of plants is to increase their photosynthetic capacity. Plants are however already very good at capturing light, so if we wish to improve photosynthesis we need to identify where the limiting steps in this process are. During the day, as the plant makes sugars, the concentration of these rise in the leaf. If the concentration of sugars becomes too high, this can slow down or stop photosynthesis. To overcome this effect, plants can convert sugars into different substances, in particular starch. Starch is relatively unreactive and does not inhibit photosynthesis. The rate at which starch can accumulate and the amount that the leaf can hold is currently metabolically limited. So, if a plant does more photosynthesis, starch accumulation cannot keep up and sugar concentrations will increase and photosynthesis will then become inhibited.Work in a weed called Thale Cress has identified, in addition to starch, a novel storage compound fumaric acid. Fumaric acid is a natural substance, found in all organisms including humans. It is widely used as a food additive to control the acidity of food and drink products. Although all plants contain fumaric acid, only a few are able to store high concentrations. In most crop species, only low amounts are found. If we could breed crops that, in addition to starch, are able to store fumaric acid in their leaves, , we may be able to increase plants' ability to carry out photosynthesis. The aim of this project is to test this idea and see whether it leads to an increase in the plants overall growth. The results obtained will be used to direct future plant breeding strategies in crops and with future development will play an important role in feeding the world's population.