Physiological and Molecular Investigation of Urea Uptake Dynamics in Cucumis sativus L. Plants Fertilized With Urea-Doped Amorphous Calcium Phosphate Nanoparticles.

Sebastian B Feil,Youry Pii,Federica Gaiotti,Francisco J Carmona,Giacomo Rodegher,Monica Yorlady Alzate Zuluaga,Stefano Cesco,Norberto Masciocchi

doi:10.3389/fpls.2021.745581

Sebastian B Feil, Youry Pii + Show 6 more

Open Access

https://doi.org/10.3389/fpls.2021.745581

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Abstract

At present, the quest for innovative and sustainable fertilization approaches aiming to improve agricultural productivity represents one of the major challenges for research. In this context, nanoparticle-based fertilizers can indeed offer an interesting alternative with respect to traditional bulk fertilizers. Several pieces of evidence have already addressed the effectiveness of amorphous calcium phosphate-based nanoparticles as carriers for macronutrients, such as nitrogen (N), demonstrating increase in crop productivity and improvement in quality. Nevertheless, despite N being a fundamental nutrient for crop growth and productivity, very little research has been carried out to understand the physiological and molecular mechanisms underpinning N-based fertilizers supplied to plants via nanocarriers. For these reasons, this study aimed to investigate the responses of Cucumis sativus L. to amorphous calcium phosphate nanoparticles doped with urea (U-ACP). Urea uptake dynamics at root level have been investigated by monitoring both the urea acquisition rates and the modulation of urea transporter CsDUR3, whereas growth parameters, the accumulation of N in both root and shoots, and the general ionomic profile of both tissues have been determined to assess the potentiality of U-ACP as innovative fertilizers. The slow release of urea from nanoparticles and/or their chemical composition contributed to the upregulation of the urea uptake system for a longer period (up to 24 h after treatment) as compared to plants treated with bulk urea. This prolonged activation was mirrored by a higher accumulation of N in nanoparticle-treated plants (approximately threefold increase in the shoot of NP-treated plants compared to controls), even when the concentration of urea conveyed through nanoparticles was halved. In addition, besides impacting N nutrition, U-ACP also enhanced Ca and P concentration in cucumber tissues, thus having possible effects on plant growth and yield, and on the nutritional value of agricultural products.

Highlights

The population inhabiting the Earth is predicted to reach almost 10 billion by 2050 (Taiz, 2013)
While the not induced and 1 mM urea-induced plants showed a similar pattern of urea uptake rates, to a different extent, the plants treated with NP behaved differently
In the NP-treated plants, the urea uptake rate did not display a down-regulation within the time interval of the experiment, but it was maintained at the same levels reached soon after the treatments

Summary

Introduction

The population inhabiting the Earth is predicted to reach almost 10 billion by 2050 (Taiz, 2013). For instance, it has been estimated that the average NUE for N-based fertilizers is approximately 50%, implying that half of the total N applied is not used by crops and lost in the environment (Lassaletta et al, 2014) To overcome these issues, several solutions have been adopted, for instance, soilless cultivation (Sambo et al, 2019). The development of new types of fertilizers might represent a suitable approach to help intensify the agriculture production in a sustainable manner In this context, the exploitation of nanotechnologies for the delivery of nutrients to crops can be envisaged as an interesting novel solution (Kopittke et al, 2019)

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