PT  - JOURNAL ARTICLE
AU  - Arthur Poitout
AU  - Amandine Crabos
AU  - Ivan Petřík
AU  - Ondrej Novák
AU  - Gabriel Krouk
AU  - Benoît Lacombe
AU  - Sandrine Ruffel
TI  - Root Responses to Heterogeneous Nitrate Availability are Mediated by <em>trans</em>-Zeatin in Arabidopsis Shoots
AID  - 10.1101/242420
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 242420
4099  - http://biorxiv.org/content/early/2018/01/04/242420.short
4100  - http://biorxiv.org/content/early/2018/01/04/242420.full
AB  - Plants are subjected to variable nitrogen (N) availability including frequent spatial nitrate (NO3-) heterogeneity in soil. Thus, plants constantly adapt their genome expression and root physiology in order to optimize N acquisition from this heterogeneous source. These adaptations rely on a complex and long-distance root-shoot-root signaling network that is still largely unknown. Here, we used a combination of reverse genetics, transcriptomic analysis, NO3- uptake experiments and hormone profiling under conditions of homogeneous or heterogeneous NO3- availability to characterize the systemic signaling involved. We demonstrate the important role of the trans-zeatin form of cytokinin (CK) in shoots, in particular using a mutant altered for ABCG14-mediated trans-zeatin-translocation from the root to the shoot, in mediating: (i) rapid long distance N-demand signaling and (ii) long term functional adaptations to heterogeneous NO3- supply, including changes in NO3- transport capacity and root growth modifications. We also provide insights into the potential CK-dependent and independent shoot-to-root signals involved in root adaptation to heterogeneous N availability.