IBIP seminar – MISTRAL Summer School

Tuesday, July 10, 2018
at 2:00 pm, amphi 2016


Plant responses to internal nitrogen satiety

Takushi Hachiya
Nagoya University

Most plants utilize nitrate and ammonium as nitrogen (N) sources. Nitrate serves as a nutrient and also as a signal molecule for plants. Exogenously supplied nitrate changes the expression of nitrate-responsive genes within minutes in roots. Following the rapid transcriptional event, nitrate and its downstream organic N compounds accumulate in the plant body, which induces secondary responses to the internal N. Our recent study has indicated that internal nitrate in the shoot acts as a N satiety signal to trigger local- and systemic signaling cascades. On the other hand, ammonium at millimolar concentrations as sole N source results in growth suppression. This phenomenon is widely known as ammonium toxicity, but its underlying mechanism remains unclear, since it was documented first by Charles Darwin. Our analysis using isolated ammonium-tolerant lines has revealed that excessive assimilation of ammonium rather than ammonium accumulation causes the toxicity. In my talk, I will present our recent advances on plant responses to internal nitrogen satiety, focusing on (1) Internal nitrate signaling and (2) Mechanism of ammonium toxicity.

Contact : Anne-Aliénor Véry