Nitrogen (N) is the most limiting nutrient for the growth of terrestrial plants. Nitrate (NO3¿) is the primary N source for plants and a signalling molecule involved in multiple physiological and developmental processes in the plant (1). Due to its significance, the nutrition of NO3¿ in plants has been extensively studied, and the use of fertilizers containing synthetic NO3¿ has been abused in modern agriculture, dealing to profound environmental concerns. Chloride (Cl-) has been traditionally considered of little importance for agriculture and even a toxic component of soils and irrigation waters, linking it to the toxic effects of salinity and to NO3¿ antagonism. Chloride shares with NO3¿ physicochemical properties, osmoregulatory functions and transport mechanisms, reason why It has been considered that Cl- hinders the plants¿ ability to take NO3¿ from the soil. But recently, our lab has reported biological functions of Chloride (Cl¿) in higher plants when accumulated to typical macronutrient levels, which contribute to increase the plant efficiency in the use of water, N, and carbon, essential components of plant nutrition (2,3). Our results show that, contrary to established beliefs, Cl¿ improves N-use efficiency by enhancing NO3¿ assimilation, having little effect on NO3¿ uptake. Considering the inefficient use of nitrogen in agriculture (up to 70% of supplied nitrogen is lost) (4), which can lead to eutrophication of freshwater (e.g. Mar Menor, Murcia); this thesis aims to characterize the molecular regulation of Cl¿ homeostasis in plants through identification of both transport mechanisms and regulatory components. We are currently investigating to which extent the regulatory components involved in the control of NO3¿ uptake (e.g. NRT1.1/NPF6.3, NAR2, LPT7, CIPK23, etc.) are also key components regulating Cl¿ uptake in plants under the hypothesis that reduction of NO3¿ availability in the soil strongly induces root Cl¿ uptake to improve the plant efficiency in the use of the scarcely available N.

Póster presentado a I “ANDALUCÍA AGRO-HUB” PhD students Meeting. Book of Abstracts. 11-12 marzo, Málaga (2024)

We acknowledge funding by MICINN FEDER Projects PID2021-125157OB-I00 and RTI2018-094460-B-I00

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