Light-independent sugar signalling in Arabidopsis

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Sugar metabolism is a fundamental biological process providing energy and the molecular building blocks to sustain life on our planet. 'Green organisms', such as plants and algae, use light energy from the sun to convert carbon dioxide into stored energy in the form of sugars while producing the oxygen we breathe. This process, known as photosynthesis, is probably the most important metabolic process on the planet. Photosynthetic organisms living in the 'primordial soup' produced the oxygen which gave rise to the Great Oxidation Event ~2.5 billion years ago, facilitating a massive evolutionary advance. Plants are among the descendants of these organisms, which continue to provide most of the energy necessary to sustain life today. Therefore, investigating how plants sense and respond to sugars is a fundamentally important research question in biology. Through improved understanding of these processes, we can gain valuable insight and develop tools to improve efficiency and total productivity of agriculture to feed the growing population around the world.Since photosynthesis depends on light, it must be effectively regulated to optimise use of daylight. Sugars must be transported to tissues that cannot photosynthesise to meet their energy needs and stored appropriately to last the night. Furthermore, as daylength and seasons change, plants need to be able to adapt to the changes in environment while maintaining optimal carbohydrate metabolism. Coordination of these processes requires mechanisms for plants to sense and respond to sugar availability. The requirement for light in sugar production in plants adds complexity that is a critical consideration to understand these endogenous sugar signalling pathways in photosynthetic organisms. For example, it is difficult to interpret effects of sugars in the light when photosynthesis is active. There is still much to be learned about the underlying mechanisms in these processes. The main objective of this research is to identify novel components of sugar signalling in the model plant species, Arabidopsis thaliana. A novel, sensitive assay has been developed to investigate sugar responses that act independently of light signalling in plants. This assay will be used to identify genes that contribute to light-independent responses to sugars and determine the function of these genes in the context of various, physiologically relevant growth environments. Ultimately, the goal of this research is gain insight into how plants integrate sugar and light signals to optimise photosynthetic efficiency and growth. This work will use a range of genetic and molecular approaches, utilising state-of-the-art technologies to gain genome-wide information about the impacts of these processes.