A Role for the AKT1 Potassium Channel in Plant Nutrition

Hirsch, Rebecca E.; Lewis, Bryan D.; Spalding, Edgar P.; Sussman, Michael R.

doi:10.1126/science.280.5365.918

Cited by 648 publications

(528 citation statements)

References 18 publications

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“…How-Yi Wang et al 827 npg ever, little is known about the regulatory mechanism of these K + transporters. AKT1 has been identified as an important dual-affinity inward-rectifying K + channel participating in K + uptake from soil into cells in Arabidopsis roots [9][10][11][12]. More recently, we have demonstrated that AKT1 activity is positively regulated by a protein kinase AtCIPK23, and AtCIPK23 is in turn activated by AtCBL1 or AtCBL9 [13].…”

Section: Introductionmentioning

confidence: 74%

Potassium channel α-subunit AtKC1 negatively regulates AKT1-mediated K+ uptake in Arabidopsis roots under low-K+ stress

Wang

et al. 2010

Cell Res

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Potassium transporters play crucial roles in K + uptake and translocation in plants. However, so far little is known about the regulatory mechanism of potassium transporters. Here, we show that a Shaker-like potassium channel AtKC1, encoded by the AtLKT1 gene cloned from the Arabidopsis thaliana low-K + (LK)-tolerant mutant Atlkt1, significantly regulates AKT1-mediated K + uptake under LK conditions. Under LK conditions, the Atkc1 mutants maintained their root growth, whereas wild-type plants stopped their root growth. Lesion of AtKC1 significantly enhanced the tolerance of the Atkc1 mutants to LK stress and markedly increased K + uptake and K + accumulation in the Atkc1-mutant roots under LK conditions. Electrophysiological results showed that AtKC1 inhibited the AKT1-mediated inward K + currents and negatively shifted the voltage dependence of AKT1 channels. These results demonstrate that the 'silent' K + channel α-subunit AtKC1 negatively regulates the AKT1-mediated K + uptake in Arabidopsis roots and consequently alters the ratio of root-to-shoot under LK stress conditions. Keywords: Arabidopsis; potassium channel; low-K + stress; AKT1; AtKC1 Cell Research (2010) IntroductionPotassium is an essential mineral element for plant growth and development, and it plays essential roles in many important physiological and biochemical processes in living plant cells, such as regulation of enzyme activation, electrical neutralization, osmoregulation, control of membrane potential, co-transport of sugars, and so on [1,2]. Plant growth and development need millimolar K + in the soil or growth medium, but typical K + concentration at the interface of roots and soils is within micromolar range [3]. Thus, plants often encounter low-K + (LK) stress under natural conditions. Although different plants or different genotypes of a plant species show varied K + utilization efficiency [4], most plants show K + -deficient symptom under LK stress, typically leaf chlorosis and subsequent inhibition of plant growth and development [5].Absorption of K + by plant cells and K + translocation between different tissues and organs in plants are mediated by plant K + transporters and channels [2,6,7]. Over the past decade, a large number of genes encoding plant K + transporters and channels, particularly for Arabidopsis, have been characterized [6][7][8]. These K + transporters vary in K + affinity, kinetics, transcriptional modulation, regulatory mechanism, etc [2,[6][7][8], and they compose a complex system for plant K + uptake and translocation. Among these K + transporters and channels, members of the Shaker K + channel family are well characterized for their potential functions and are probably the most important for K + uptake and transport in Arabidopsis [8] Recent reports showed that channel heterotetramerization is a key regulatory mechanism for K + channels, which was found not only in animals [14][15][16] but also in plants [17,18]. Different kinds of potassium channel subunits may assemble together to form functional heteromer...

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Section: Introductionmentioning

confidence: 74%

Potassium channel α-subunit AtKC1 negatively regulates AKT1-mediated K+ uptake in Arabidopsis roots under low-K+ stress

Wang

et al. 2010

Cell Res

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“…This resting potential is set by the PM H + -ATPase and is normally kept close to the equilibrium potential for K + (Hirsch et al, 1998). Under salinity, the membrane depolarizes following the influx of positively charged Na + ions, which shifts membrane potential values above the equilibrium potential for K + and results in significant outward K + currents (Anschütz et al, 2014;Véry et al, 2014).…”

Section: Intrinsically Higher H + -Atpase Activity Is Essential To Comentioning

confidence: 99%

Cell-Type-Specific H⁺-ATPase Activity in Root Tissues Enables K⁺ Retention and Mediates Acclimation of Barley (Hordeum vulgare) to Salinity Stress

et al. 2016

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While the importance of cell type specificity in plant adaptive responses is widely accepted, only a limited number of studies have addressed this issue at the functional level. We have combined electrophysiological, imaging, and biochemical techniques to reveal the physiological mechanisms conferring higher sensitivity of apical root cells to salinity in barley (Hordeum vulgare). We show that salinity application to the root apex arrests root growth in a highly tissue-and treatment-specific manner. Although salinity-induced transient net Na + uptake was about 4-fold higher in the root apex compared with the mature zone, mature root cells accumulated more cytosolic and vacuolar Na + , suggesting that the higher sensitivity of apical cells to salt is not related to either enhanced Na + exclusion or sequestration inside the root. Rather, the above differential sensitivity between the two zones originates from a 10-fold difference in K + efflux between the mature zone and the apical region (much poorer in the root apex) of the root. Major factors contributing to this poor K + retention ability are (1) an intrinsically lower H + -ATPase activity in the root apex, (2) greater saltinduced membrane depolarization, and (3) a higher reactive oxygen species production under NaCl and a larger density of reactive oxygen species-activated cation currents in the apex. Salinity treatment increased (2-to 5-fold) the content of 10 (out of 25 detected) amino acids in the root apex but not in the mature zone and changed the organic acid and sugar contents. The causal link between the observed changes in the root metabolic profile and the regulation of transporter activity is discussed.

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“…The negative membrane potential (-200 mV) within the plasma membrane in epidermal cells of roots (HIRSCH et al, 1998) provides a strong driving force for absorption of cations through secondary carriers. For example, the carriers of heavy metals in plants fall into four different families: as the CPx-ATPases, Nramps, CDF (facilitator of diffusion of cations), and ZIP, which are involved in the absorption of metals and homeostasis in general, playing a key role in tolerance to these elements (SETH, 2012).…”

Section: Absorption Transport and Plant Toxicity Of Heavy Metalsmentioning

confidence: 99%

Heavy Metals in Vineyards and Orchard Soils

et al. 2017

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-The application of foliar fungicides in vineyards and orchards can increase soil concentration of heavy metals such as copper (Cu) and zinc (Zn), up to the toxicity threshold for fruit trees and cover crops. However, some agronomic practices, such as liming, addition of organic fertilizers, cultivation of soil cover crops and inoculation of young plants with arbuscular mycorrhizal fungi can decrease the availability and the potential of heavy metal toxicity to fruit trees. This review aims to compile and present information about the effects of increasing concentrations of heavy metals, especially Cu and Zn, on soils cultivated with fruit trees and provides some agronomic practices of remediation. Information about the sources of heavy metals found in soils cultivated with fruit trees are presented; mechanisms of absorption, transport, accumulation and potential toxicity to plants are described. Index terms: Trace element, phytotoxicity, growth, fruit trees. METAIS PESADOS EM SOLOS DE VINHEDOS E POMARESRESUMO -A aplicação de fungicidas foliares em vinhedos e pomares pode incrementar os teores de metais pesados, como o cobre (Cu) e o zinco (Zn), em solos e, quando em excesso, podem causar toxidez às frutíferas ou plantas de cobertura. Porém, algumas práticas agronômicas, como a calagem, adição de resíduos orgânicos, cultivo de plantas de cobertura do solo e inoculação de plantas jovens com fungos micorrízicos arbusculares (FMA) podem diminuir a disponibilidade e o potencial de toxidez de metais pesados às frutíferas. A presente revisão objetivou compilar e apresentar informações sobre os efeitos do aumento dos teores de metais pesados, especialmente, Cu e Zn, em solos cultivados com frutíferas e algumas práticas agronômicas de remediação. Ao longo do texto são apresentadas informações sobre as fontes de metais pesados, com enfase no Cu e Zn, em solos cultivados com frutíferas; mecanismos de absorção, transporte, acúmulo e potencial de toxidez às plantas. Além disso, são relatadas algumas práticas agronômicas viáveis para remediar o potencial de toxidez de metais pesados em solos cultivados com frutíferas. Com a adoção destas práticas se espera menor disponibilidade de metais pesados no solo, o que reduziria o potencial de toxidez às plantas, especialmente, em frutíferas jovens transplantadas em solos com alto teor de metais pesados, como o Cu e Zn, permitindo satisfatório crescimento, produção e composição de frutos. Termos para indexação: Elemento traço, fitotoxidez, crescimento, frutíferas.1 (Paper 226-15).

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A Role for the AKT1 Potassium Channel in Plant Nutrition

Cited by 648 publications

References 18 publications

Potassium channel α-subunit AtKC1 negatively regulates AKT1-mediated K+ uptake in Arabidopsis roots under low-K+ stress

Potassium channel α-subunit AtKC1 negatively regulates AKT1-mediated K+ uptake in Arabidopsis roots under low-K+ stress

Cell-Type-Specific H⁺-ATPase Activity in Root Tissues Enables K⁺ Retention and Mediates Acclimation of Barley (Hordeum vulgare) to Salinity Stress

Heavy Metals in Vineyards and Orchard Soils

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A Role for the AKT1 Potassium Channel in Plant Nutrition

Cited by 648 publications

References 18 publications

Potassium channel α-subunit AtKC1 negatively regulates AKT1-mediated K+ uptake in Arabidopsis roots under low-K+ stress

Potassium channel α-subunit AtKC1 negatively regulates AKT1-mediated K+ uptake in Arabidopsis roots under low-K+ stress

Cell-Type-Specific H+-ATPase Activity in Root Tissues Enables K+ Retention and Mediates Acclimation of Barley (Hordeum vulgare) to Salinity Stress

Heavy Metals in Vineyards and Orchard Soils

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Cell-Type-Specific H⁺-ATPase Activity in Root Tissues Enables K⁺ Retention and Mediates Acclimation of Barley (Hordeum vulgare) to Salinity Stress