Elucidate the role of energy and sugar-responsive bZIP transcription factors in the regulation of starch metabolism in Arabidopsis

• Grant number: 19/25993-9
• Support type: Regular Research Grants
• Duration: July 01, 2020 - June 30, 2022
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Cooperation agreement: Max Planck Society for the Advancement of Science
• Principal Investigator: Michel Georges Albert Vincentz
• Grantee: Michel Georges Albert Vincentz
• Principal investigator abroad: Camila Caldana
• Institution abroad: Max Planck Society, Potsdam, Germany
• Home Institution: Centro de Biologia Molecular e Engenharia Genética (CBMEG). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Efficient management of an organism's energy resources is crucial to ensure its development and reproduction. As sessile organisms, plants have evolved sophisticated mechanisms to optimize the balanced use of energy sources in response to environmental changes. Carbohydrates such as sucrose and starch (sugar reserve), resulting from CO2 fixation by photosynthesis during the daytime, represent the primary source of energy. At night, in Arabidopsis thaliana (Arabidopsis), starch is degraded at a rate compatible with a regular carbohydrate supply to sustain growth until dawn. We obtained evidence that the regulation of this process involves the interaction of the circadian clock and the bZIP Transcription Factor (TF) AtbZIP63 (bZIP63). We show that this TF modulates the expression of PRR7, a key clock gene, to adjust the phase of the circadian oscillator in response to sugars. bZIP63 is in turn regulated by the circadian oscillator. bZIP63 is also a key target of SnRK1/KIN10 kinase to activates energy stress responses. Preliminary results of our group indicate that bZIP1 and bZIP53, two dimerization partners of bZIP63, are also involved in controlling starch metabolism. Overall, the proposal aims to obtain new insights into how bZIP1,53 and 63 TFs- integrate energy status and interacts with the circadian clock to regulate starch metabolism. More specifically, the project intends to evaluate the role of bZIP1,53 and 63 regulators in managing contrasting energy resources levels arising from different light conditions (photoperiod and intensity). New aspects about the mechanisms involved in the regulation of growth in response to dynamic fluctuations of energy resources are expected to be obtained. (AU)