Nitrogen depletion enhances endodermal suberization without restricting transporter-mediated root NO3- influx

Abstract
Roots vary their permeability to aid radial transport of solutes towards xylem vessels in response to nutritional cues. Nitrogen (N) depletion was previously shown to induce early suberization of endodermal cell walls and reduce hydraulic conductivity of barley roots suggesting reduced apoplastic transport of ions (Armand et al., 2019). Suberization may also limit transcellular ion movement by blocking access to transporters (Barberon et al., 2016). The aim of this study was to confirm that N depletion induced suberization in the roots of barley and demonstrate that this was a specific effect in response to NO depletion. Furthermore, in roots with early and enhanced suberization, we assessed their ability for transporter-mediated NO influx. N depletion induced lateral root elongation and early and enhanced endodermal suberization of the seminal root of each genotype. Both root to shoot NO translocation and net N uptake was half that of plants supplied with steady-state NO. Genes with predicted functions in suberin synthesis (HvHORST) and NO transport (HvNRT2.2) were induced under N-deplete conditions. N-deplete roots had a higher capacity for high-affinity NO- influx in early suberized roots than under optimal NO. In conclusion, NO depletion induced early and enhanced suberization in the roots of barley, however, suberization did not restrict transcellular NO transport.

Citation
Melino, V. J., Plett, D. C., Bendre, P., Thomsen, H. C., Zeisler-Diehl, V. V., Schreiber, L., & Kronzucker, H. J. (2021). Nitrogen depletion enhances endodermal suberization without restricting transporter-mediated root NO3- influx. Journal of Plant Physiology, 257, 153334. doi:10.1016/j.jplph.2020.153334

Acknowledgements
The authors would like to acknowledge the University of Melbourne, School of Agriculture and Food research investment fund, Australia. We acknowledge the Melbourne Histology and Histopathology platform and expert advice of Laura Leone and the University of Melbourne Biological Optical Microscopy (BOMP) platform. We would like to acknowledge Melbourne TrACEES Platform for the service and expert advice by Michael Hall.

Publisher
Elsevier BV

Journal
Journal of plant physiology

DOI
10.1016/j.jplph.2020.153334

PubMed ID
33373827

Additional Links
https://linkinghub.elsevier.com/retrieve/pii/S0176161720302248

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