Relation between metabolic control of leaf senescence by carbohydrates and nitrogen metabolism

• Applicant: Professor Dr. Thomas Roitsch
• Subject Area: Plant Cultivation, Plant Nutrition, Agricultural Technology
• Term: from 2009 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 46691270

Although leaf senescence has been shown to be accompanied by changes in carbohydrate composition and levels, the role of sugars in the initiation and regulation of senescence is a matter of debate. The hydrolysis of the transported sugar sucrose by an extracellular invertase is a key step in regulating phloem unloading. Based on the finding that an extracellular invertase is essential for cytokinin mediated delay of senescence, the present study addresses the metabolic control by carbohydrates and the role of source-sink relations on the remobilisation of nitrogen during senescence in rapeseed. The carbohydrate metabolism in source and sink tissues during nitrogen deficiency-induced and senescence-induced N remobilisation will be characterized at the level of gene expression, key enzymatic activities and metabolites. In functional approaches transgenic rapeseed plants will be generated with modulated sugar status and cytokinin content in source and sink tissues. These plants will be supplied to and analyzed by the Research Unit with respect to a number of complementing parameters. A rapeseed transformation platform will be provided for the Research Unit.

• DFG Programme: Research Units
• Subproject of: FOR 948: Nitrogen Uptake, Metabolism and Remobilisation in Leaves during Plant Senescence
• International Connection: Austria