The Arabidopsis thaliana HAK5 K+ Transporter Is Required for Plant Growth and K+ Acquisition from Low K+ Solutions under Saline Conditions

Nieves‐Cordones, Manuel; Alemán, Fernando; Martı́nez, Vicente; Rubio, Francisco

doi:10.1093/mp/ssp102

Cited by 210 publications

(150 citation statements)

References 43 publications

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“…NO is a plantendogenous messenger involved in growth and multiple stress responses (14,44,48). Here, we show that NO negatively regulates the absorption of K + , an ion that has marked impacts on cell metabolism, plant growth, and stress adaption (26,52). Plant growth rate correlates with K + uptake (26,53), and less K + uptake will retard plant growth.…”

Section: Discussionmentioning

confidence: 93%

“…Studies showed that under K + -deprived saline conditions where plant K + contents diminished dramatically, AKT1-mediated K + efflux was promoted, and AtHAK5 transcription was also largely reduced (52), suggesting that the regulation of K + contents in this situation happens at various aspects. The possible effect of NO on AtHAK5 transporter, especially in low K + conditions, remains to be addressed.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Nitric oxide negatively regulates AKT1-mediated potassium uptake through modulating vitamin B6 homeostasis in Arabidopsis

Xia

Kong

Xue

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Nitric oxide (NO), an active signaling molecule in plants, is involved in numerous physiological processes and adaptive responses to environmental stresses. Under high-salt conditions, plants accumulate NO quickly, and reorganize Na + and K + contents. However, the molecular connection between NO and ion homeostasis is largely unknown. Here, we report that NO lowers K + channel AKT1-mediated plant K + uptake by modulating vitamin B6 biosynthesis. In a screen for Arabidopsis NO-hypersensitive mutants, we isolated sno1 (sensitive to nitric oxide 1), which is allelic to the previously noted mutant sos4 (salt overly sensitive 4) that has impaired Na + and K + contents and overproduces pyridoxal 5′-phosphate (PLP), an active form of vitamin B6. We showed that NO increased PLP and decreased K + levels in plant. NO induced SNO1 gene expression and enzyme activity, indicating that NO-triggered PLP accumulation mainly occurs through SNO1-mediated vitamin B6 salvage biosynthetic pathway. Furthermore, we demonstrated that PLP significantly repressed the activity of K + channel AKT1 in the Xenopus oocyte system and Arabidopsis root protoplasts. Together, our results suggest that NO decreases K + absorption by promoting the synthesis of vitamin B6 PLP, which further represses the activity of K + channel AKT1 in Arabidopsis. These findings reveal a previously unidentified pivotal role of NO in modulating the homeostasis of vitamin B6 and potassium nutrition in plants, and shed light on the mechanism of NO in plant acclimation to environmental changes.genetic approach | electrophysiological studies | potassium nutrition N itric oxide (NO) acts as a crucial signaling molecule in various physiological processes in plants, such as seed germination and dormancy (1, 2), root development (3), leaf senescence (4, 5), floral transition (6), stomatal movement (7, 8), iron homeostasis (9, 10), and hormone responses (11,12). NO production is altered when plants are subjected to abiotic or biotic stresses (13,14). High salt, a major environmental factor that limits agriculture yield, induces a quick endogenous NO accumulation in plants (15,16), and triggers enhanced Na + influx and reduced K + absorption in the root (17). Both endogenously produced NO and exogenously applied NO have been proposed to enhance plant salt tolerance (18-21) by attenuating high saltinduced increases in the Na + to K + ratio. Genetic analysis showed that K + nutrition, but not Na + , plays critical role in plant salt tolerance (22). However, the molecular basis of NO effect on K + or Na + content is elusive.K + levels in plant tissues are determined by K + uptake and translocation, which are mediated by a large number of transporters and channels. In Arabidopsis, the K + channel AKT1 (23, 24) and K + transporter AtHAK5 (25) are the two major molecular entities responsible for K + absorption from the environment (26-28). AKT1 contributes to K + acquisition over a wide range of external K + concentrations (10 μM-10 mM), whereas AtHAK5 mediates limited uptake capac...

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Nitric oxide negatively regulates AKT1-mediated potassium uptake through modulating vitamin B6 homeostasis in Arabidopsis

Xia

Kong

Xue

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…In Arabidopsis, AKT1 probably acts as K + sensor because it has dual-affinity activity and its phosphorylation based regulation by CIPK23 similar to the NO 3 − sensor, i.e., CHL1 transporter (Schroeder and Fang 1991;Li et al 2006;Xu et al 2006). In plants, the hyperpolarization (Maathuis and Sanders 1994;Nieves-Cordones et al 2010) and depolarization (Spalding et al 1999) of membrane potential at low and high external K + concentration respectively may act as K + sensing mechanisms. Plant undergoes both short-and long-term responses after signal perception (Schachtman and Shin 2007).…”

Section: Introductionmentioning

confidence: 99%

NPKS uptake, sensing, and signaling and miRNAs in plant nutrient stress

Nath

Tuteja

2015

Protoplasma

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Sessile nature of higher plants consequently makes it highly adaptable for nutrient absorption and acquisition from soil. Plants require 17 essential elements for their growth and development which include 14 minerals (macronutrients: N, P, K, Mg, Ca, S; micronutrients: Cl, Fe, B, Mn, Zn, Cu, Ni, Mo) and 3 non-mineral (C, H, O) elements. The roots of higher plants must acquire these macronutrients and micronutrients from rhizosphere and further allocate to other plant parts for completing their life cycle. Plants evolved an intricate series of signaling and sensing cascades to maintain nutrient homeostasis and to cope with nutrient stress/availability. The specific receptors for nutrients in root, root system architecture, and internal signaling pathways help to develop plasticity in response to the nutrient starvation. Nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) are essential for various metabolic processes, and their deficiency negatively effects the plant growth and yield. Genes coding for transporters and receptors for nutrients as well as some small non-coding RNAs have been implicated in nutrient uptake and signaling. This review summarizes the N, P, K, and S uptake, sensing and signaling events in nutrient stress condition especially in model plant Arabidopsis thaliana and involvement of microRNAs in nutrient deficiency. This article also provides a framework of uptake, sensing, signaling and to highlight the microRNA as an emerging major players in nutrient stress condition. Nutrient-plant-miRNA cross talk may help plant to cope up nutrient stress, and understanding their precise mechanism(s) will be necessary to develop high yielding smart crop with low nutrient input.

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“…In Arabidopsis (Arabidopsis thaliana), the high-affinity K + transporter HAK5 (Rubio et al, 2000;Nieves-Cordones et al, 2010) and the Shaker inward K + channel AKT1 (Lagarde et al, 1996;Hirsch et al, 1998;Spalding et al, 1999;Ivashikina et al, 2001) have been considered two major components that conduct K + uptake in root cells under low-K + (LK) conditions (Gierth et al, 2005;Pyo et al, 2010;Nieves-Cordones et al, 2014). The transcription of HAK5 is induced by K + deficiency (Gierth et al, 2005), which is an important mechanism in plant responses to LK stress .…”

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confidence: 99%

AtKC1 and CIPK23 Synergistically Modulate AKT1-Mediated Low-Potassium Stress Responses in Arabidopsis

et al. 2016

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In Arabidopsis (Arabidopsis thaliana), the Shaker K + channel AKT1 conducts K + uptake in root cells, and its activity is regulated by CBL1/9-CIPK23 complexes as well as by the AtKC1 channel subunit. CIPK23 and AtKC1 are both involved in the AKT1-mediated low-K + (LK) response; however, the relationship between them remains unclear. In this study, we screened suppressors of low-K + sensitive [lks1 (cipk23)] and isolated the suppressor of lks1 (sls1) mutant, which suppressed the leaf chlorosis phenotype of lks1 under LK conditions. Map-based cloning revealed a point mutation in AtKC1 of sls1 that led to an amino acid substitution (G322D) in the S6 region of AtKC1. The G322D substitution generated a gain-of-function mutation, AtKC1 D , that enhanced K + uptake capacity and LK tolerance in Arabidopsis. Structural prediction suggested that glycine-322 is highly conserved in K + channels and may function as the gating hinge of plant Shaker K + channels. Electrophysiological analyses revealed that, compared with wild-type AtKC1, AtKC1 D showed enhanced inhibition of AKT1 activity and strongly reduced K + leakage through AKT1 under LK conditions. In addition, phenotype analysis revealed distinct phenotypes of lks1 and atkc1 mutants in different LK assays, but the lks1 atkc1 double mutant always showed a LK-sensitive phenotype similar to that of akt1. This study revealed a link between CIPK-mediated activation and AtKC1-mediated modification in AKT1 regulation. CIPK23 and AtKC1 exhibit distinct effects; however, they act synergistically and balance K + uptake/leakage to modulate AKT1-mediated LK responses in Arabidopsis.

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The Arabidopsis thaliana HAK5 K+ Transporter Is Required for Plant Growth and K+ Acquisition from Low K+ Solutions under Saline Conditions

Cited by 210 publications

References 43 publications

Nitric oxide negatively regulates AKT1-mediated potassium uptake through modulating vitamin B6 homeostasis in Arabidopsis

Nitric oxide negatively regulates AKT1-mediated potassium uptake through modulating vitamin B6 homeostasis in Arabidopsis

NPKS uptake, sensing, and signaling and miRNAs in plant nutrient stress

AtKC1 and CIPK23 Synergistically Modulate AKT1-Mediated Low-Potassium Stress Responses in Arabidopsis

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