Role of cis-zeatin in root responses to phosphate starvation

Silva-Navas, Javier; Conesa, Carlos M.; Saez, Angela; Navarro-Nelia, Sara; Garcia-Mina, Jose M.; Zamarre�o, Angel M.; Baigorri, Roberto; Swarup, Ranjan; del Pozo, Juan C.

Abstract

Phosphate (Pi) is an essential nutrient for all organisms. Root are underground organs, but the majority of the root biology studies have been done growing the root system in presence of light.

Root illumination alters the Pi starvation response (PSR) at different levels. Thus, we have analyzed morphological, transcriptional and physiological responses to Pi starvation in dark‐grown roots.

We have identified new genes and pathways regulated by Pi starvation that were not described previously. We also show that Pi‐starved plants increase the cis‐zeatin (cZ)/trans‐zeatin (tZ) ratio. Transcriptomic analyses show that tZ preferentially represses cell cycle and PSR genes while cZ induces genes involved in cell and root hair elongation and differentiation. In fact, cZ‐treated seedlings show longer root system as well as longer root hairs than tZ‐treated, increasing the total absorbing surface. Mutants with low cZ levels do not allocate free Pi in roots during Pi starvation.

We propose that Pi‐starved plants increase the cZ/tZ ratio to maintain basal CK responses and allocate Pi in the root system to sustain its growth. Therefore, cZ acts as a Pi‐starvation response hormone that stimulates root and root hair elongation to enlarge root absorbing surface and to increase Pi levels in roots.

Citation

Silva-Navas, J., Conesa, C. M., Saez, A., Navarro-Nelia, S., Garcia-Mina, J. M., Zamarreño, A. M., Baigorri, R., Swarup, R., & del Pozo, J. C. (2019). Role of cis-zeatin in root responses to phosphate starvation. New Phytologist, 224(1), 242-257. https://doi.org/10.1111/nph.16020

• Journal Article Type: Article
• Acceptance Date: Jun 17, 2019
• Online Publication Date: Jun 22, 2019
• Publication Date: Oct 1, 2019
• Deposit Date: Jun 19, 2019
• Publicly Available Date: Jun 23, 2020
• Journal: New Phytologist
• Print ISSN: 0028-646X
• Electronic ISSN: 1469-8137
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 224
• Issue: 1
• Pages: 242-257
• DOI: https://doi.org/10.1111/nph.16020
• Keywords: Phosphate starvation, Ciz-zeatin, Arabidopsis, Root hair, Root system
• Public URL: https://nottingham-repository.worktribe.com/output/2208344
• Publisher URL: https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.16020
• Additional Information: This is the peer reviewed version of the following article: Silva‐Navas, J. , Conesa, C. M., Saez, A. , Navarro‐Neila, S. , Garcia‐Mina, J. M., Zamarreño, A. M., Baigorri, R. , Swarup, R. and del Pozo, J. C. (2019), Role of cis‐zeatin in root responses to phosphate starvation. New Phytol. , which has been published in final form at https://doi.org/10.1111/nph.16020. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
• Contract Date: Jun 19, 2019