Förderkennzeichen: DFG FOR 948
Ammonium is a central intermediate in plant nitrogen metabolism and in particular during plant senescence ammonium is generated and re-assimilated at high rate. Imbalance in ammonium handling may lead to growth impairment and ammonia volatilization from the leaves. The overall aim of the project is to study bottle-necks in efficient ammonium assimilation and compartmentalisation in senescing source leaves and generative sinks.
A range of experiments will be conducted using mutants and transgenic lines in Arabidopsis, barley and oilseed rape to reveal the specific roles of isoforms of the key assimilatory enzyme glutamine synthetase and the ammonia-channelling tonoplast intrinsin proteins for NH4+ homeostasis.
Furthermore, implications of imbalances in NH4+ homeostasis for nitrogen re-mobilization from senescing leaves and plant-atmosphere ammonia exchange will be investigated. The knowledge gained will result in validation of candidate genes controlling nitrogen use efficiency which can be used to develop genetic markers for breeding of cultivars with improved nutrient use.
In an agronomic perspective, the results obtained are expected to provide an improved basis for development of new and better nitrogen application strategies allowing more intensive use of foliar fertilizers.