The reproductive success of plants largely depends on the correct programming of
developmental phase transitions, particularly the shift from vegetative to
reproductive growth. The timing of this transition is finely regulated by the
integration of an array of environmental and endogenous factors. Nitrogen is the
mineral macronutrient that plants require in the largest amount, and as such its
availability greatly impacts on many aspects of plant growth and development,
including flowering time. We found that nitrate signaling interacts with the
age-related and gibberellic acid pathways to control flowering time in
Arabidopsis thaliana. We revealed that repressors of flowering time belonging to
the AP2-type transcription factor family including SCHLAFMUTZE (SMZ) and
SCHNARCHZAPFEN (SNZ) are important regulators of flowering time in response to
nitrate. Our results support a model whereby nitrate activates SMZ and SNZ via
the gibberellin pathway to repress flowering time in Arabidopsis thaliana.
