Exposure to a natural nitric oxide donor negatively affects the potential influx of rubidium in potassium-starved Arabidopsis plants

SIMONTACCHI, MARCELA; OLIFERUK, SONIA; SANTA-MARÍA, GUILLERMO E.; OLIFERUK, SONIA; SANTA-MARÍA, GUILLERMO E.; RUBIO, FRANCISCO; RUBIO, FRANCISCO; SIMONTACCHI, MARCELA

PLANT PHYSIOLOGY AND BIOCHEMISTRY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Año: 2020 vol. 150 p. 204 - 208

0981-9428

Nitric oxide (NO) and potassium (K⁺) exert a profound influence on the acclimation of plants to multiple stress conditions. A recent report indicated that exogenous addition of an NO donor causes, under conditions of adequate K⁺ supply, a detrimental effect on K⁺ status. It remains unknown whether an exogenous NO source could negatively affect the potential capture of this element when plants are faced with a K⁺ shortage. In this work we offer evidence that, under conditions of K⁺-deprivation, the addition of the naturally occurring NO donor, S-nitrosoglutathione (GSNO), diminishes the potential inward transport of the K⁺-analogue rubidium (Rb⁺) from diluted Rb⁺ concentrations in Arabidopsis thaliana. Studies with the akt1-2 mutant, lacking the AKT1 inward-rectifier K⁺-channel involved in K⁺-uptake, unveiled that the effect of GSNO on Rb⁺-influx involves a non-AKT1 component. In addition, exposure to the NO-donor led to down-regulation of transcripts coding for the AtHAK5 K⁺-transporter, a major component of the K⁺-transport machinery in K⁺-deprived plants. Moreover, studies with the hak5 mutant showed that GSNO could either stimulate Rb⁺-uptake or does not lead to a significant effect on Rb⁺-uptake relative to ?K⁺ and to ?K⁺ in the presence of decayed GSNO, respectively, thus indicating that the presence of AtHAK5 is required for GSNO exerting an inhibitory effect.