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bioRxiv · 10.1101/242420

Root Responses to Heterogeneous Nitrate Availability are Mediated by trans-Zeatin in Arabidopsis Shoots

Poitout, A.·Crabos, A.·Petrik, I.·Novak, O.·Krouk, G.·Lacombe, B.·Ruffel, S.
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Abstract

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.

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Poitout, A., Crabos, A., Petrik, I., Novak, O., Krouk, G., Lacombe, B., Ruffel, S.. 2018-01-04. Root Responses to Heterogeneous Nitrate Availability are Mediated by trans-Zeatin in Arabidopsis Shoots. https://doi.org/10.1101/242420

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