Ions channels/transporters and chloroplast regulation

Finazzi, Guido; Petroutsos, Dimitris; Tomizioli, Martino; Flori, Serena; Sautron, Emeline; Villanova, Valeria; Rolland, Norbert; Seigneurin-Berny, Daphné

doi:10.1016/j.ceca.2014.10.002

Cited by 111 publications

(100 citation statements)

References 150 publications

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“…Many other enzymes have been shown to behave similarly (for review, see Gohara and Di Cera, 2016;Okur et al, 2017). In chloroplasts, the cation composition is dominated by K + , which may be as high as 200 mM (Finazzi et al, 2015), so K + is likely to be the in vivo activator of BAM2. KCl levels in chloroplasts fluctuate under stress conditions (Schröppel-Meier and Kaiser, 1988), so it is possible that BAM2 activity is regulated in vivo by ionic strength.…”

Section: Discussionmentioning

confidence: 99%

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Arabidopsis β-Amylase2 Is a K⁺-Requiring, Catalytic Tetramer with Sigmoidal Kinetics

et al. 2017

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Section: Discussionmentioning

confidence: 99%

“…S11). Potassium is the probable physiological activator due to its higher concentration (120-200 mM) in the chloroplast stroma (Finazzi et al, 2015). With the discovery of BAM2's catalytic activity, we next wanted to compare the kinetic properties of BAM2 with those of the three other active BAM enzymes.…”

Section: Bam2 Activity Requires High Ionic Strengthmentioning

confidence: 99%

Arabidopsis β-Amylase2 Is a K⁺-Requiring, Catalytic Tetramer with Sigmoidal Kinetics

et al. 2017

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“…In this study we found that both kea1-2kea2-2 double mutants and kea3-1 mutants showed reduced osmoticinduced Ca 2+ responses despite being grown in standard lighting conditions. These results offer the tantalizing prospect that plastidial membrane energetics and Ca 2+ stores may be linked and required for wild-type hyperosmotic-induced Ca 2+ responses (21,52). In animal systems, for instance, it has been demonstrated that mitochondria play an important function in Ca 2+ release (53,54).…”

Section: Discussionmentioning

confidence: 87%

Rapid hyperosmotic-induced Ca ²⁺ responses in Arabidopsis thaliana exhibit sensory potentiation and involvement of plastidial KEA transporters

Stephan

Kunz

Yang

et al. 2016

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

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Plants experience hyperosmotic stress when faced with saline soils and possibly with drought stress, but it is currently unclear how plant roots perceive this stress in an environment of dynamic water availabilities. Hyperosmotic stress induces a rapid rise in intracellular Ca 2+ concentrations ([Ca 2+ ] i ) in plants, and this Ca 2+ response may reflect the activities of osmo-sensory components. Here, we find in the reference plant Arabidopsis thaliana that the rapid hyperosmoticinduced Ca 2+ response exhibited enhanced response magnitudes after preexposure to an intermediate hyperosmotic stress. We term this phenomenon "osmo-sensory potentiation." The initial sensing and potentiation occurred in intact plants as well as in roots. Having established a quantitative understanding of wild-type responses, we investigated effects of pharmacological inhibitors and candidate channel/transporter mutants. Quintuple mechano-sensitive channels of small conductance-like (MSL) plasma membrane-targeted channel mutants as well as double mid1-complementing activity (MCA) channel mutants did not affect the response. Interestingly, however, double mutations in the plastid K + exchange antiporter (KEA) transporters kea1kea2 and a single mutation that does not visibly affect chloroplast structure, kea3, impaired the rapid hyperosmotic-induced Ca 2+ responses. These mutations did not significantly affect sensory potentiation of the response. These findings suggest that plastids may play an important role in early steps mediating the response to hyperosmotic stimuli. Together, these findings demonstrate that the plant osmosensory components necessary to generate rapid osmotic-induced Ca 2+ responses remain responsive under varying osmolarities, endowing plants with the ability to perceive the dynamic intensities of water limitation imposed by osmotic stress.osmotic sensing | calcium | salt stress | plastid | abscisic acid P lants exhibit a wide range of physiological responses to cope with water deprivation by drought and salinity stress (1-3). The properties of biological sensors determine the circumstances and extent to which these coping mechanisms are activated, but the early sensory mechanisms and components regulating the osmotic sensory components in plants are not well understood (see ref. 4 for review). Pioneering studies have demonstrated that Arabidopsis seedlings expressing the bioluminescent Ca 2+ reporter protein aequorin exhibit a rapid rise in intracellular Ca 2+ ([Ca 2+ ] i ) within seconds upon stimulation by NaCl solution (5, 6). This rapid osmotic-induced Ca 2+ response has been observed in plant species ranging from rice (7) to the basal-branching moss taxon Physcomitrella patens (8), indicating that this response may be conserved across the Plantae kingdom. Solutions of either NaCl or isoosmotic mannitol/sorbitol induce nearly identical rapid Ca 2+ responses, indicating that the nature of this rapid stimulus is largely osmotic rather than ionic (5, 9, 10). Individual seedling responses tend to be quite hetero...

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“…The response of K + to these compounds might be due to a maximum accumulation of nonstructural carbohydrates given by translocation of the ion K + to formation of phenyl-propanoids [11]. Once in the cytosol, K + can cross the tonoplast through conveyors or channels which are responsible for its influx into vacuoles, while channels mainly mediate its outflow to the cytosol by antiporters which catalyze the electroneutral exchange of K + and H + using an electrochemical gradient produced by H + -ATPase present in the plasma membrane of cell organelles [32,33]. This could explain that ion K + was redirected to its various functions, and due to the intense mobility in phloem and xylem was possible to regulate the internal balance for absorption and translocation of carbohydrates, affecting indirectly the formation of the basic structures of phenyl-propanoids.…”

Section: Total Phenolic Compounds Flavonoids and Anthocyanins Contentmentioning

confidence: 99%

Cultivar Variety and Added Potassium Influence the Nutraceutical and Antioxidant Content in Hydroponically Grown Basil (Ocimum basilicum L.)

Salas-Pérez¹,

Fornari-Reale

Rangel

et al. 2018

Agronomy

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Abstract:The potential impact of increased levels of potassium (K + ) in hydroponic solution on the production of bioactive compounds, which provide added value to products, is relevant for local economy and human health. This research pursues assessing different levels of K + on the nutrition of basil, an important aromatic crop in the arid region of La Laguna, northern México, where water scarcity demands the conversion from open-field agriculture to hydroponics. A randomized complete block design with a factorial arrangement (3 × 4) was used to determine the content of nutraceutical components, including polyphenolic compounds, flavonoids, anthocyanins, vitamin C, chlorophylls, and the antioxidant capacity of three varieties of hydroponic basil, with four doses of K + in the nutrient solution, 7, 9, 11 and 13 mmol L −1 . The analysis of variance showed significant differences (p ≤ 0.001) in most of the response variables, caused by the genotype and doses of K + . The antioxidant capacity of assessed cultivars was improved when doses of K + were increased in the nutrient solution. Furthermore, the antioxidant capacity was positively correlated to the content of flavonoids (r = 0.621), anthocyanins (r = 0.655) and total phenolic compounds (r = 0.549). In conclusion, the nutraceutical content was increased in basil when controlling K + in the nutrient solution.

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Ions channels/transporters and chloroplast regulation

Cited by 111 publications

References 150 publications

Arabidopsis β-Amylase2 Is a K⁺-Requiring, Catalytic Tetramer with Sigmoidal Kinetics

Arabidopsis β-Amylase2 Is a K⁺-Requiring, Catalytic Tetramer with Sigmoidal Kinetics

Rapid hyperosmotic-induced Ca ²⁺ responses in Arabidopsis thaliana exhibit sensory potentiation and involvement of plastidial KEA transporters

Cultivar Variety and Added Potassium Influence the Nutraceutical and Antioxidant Content in Hydroponically Grown Basil (Ocimum basilicum L.)

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Ions channels/transporters and chloroplast regulation

Cited by 111 publications

References 150 publications

Arabidopsis β-Amylase2 Is a K+-Requiring, Catalytic Tetramer with Sigmoidal Kinetics

Arabidopsis β-Amylase2 Is a K+-Requiring, Catalytic Tetramer with Sigmoidal Kinetics

Rapid hyperosmotic-induced Ca 2+ responses in Arabidopsis thaliana exhibit sensory potentiation and involvement of plastidial KEA transporters

Cultivar Variety and Added Potassium Influence the Nutraceutical and Antioxidant Content in Hydroponically Grown Basil (Ocimum basilicum L.)

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Product

Resources

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Arabidopsis β-Amylase2 Is a K⁺-Requiring, Catalytic Tetramer with Sigmoidal Kinetics

Arabidopsis β-Amylase2 Is a K⁺-Requiring, Catalytic Tetramer with Sigmoidal Kinetics

Rapid hyperosmotic-induced Ca ²⁺ responses in Arabidopsis thaliana exhibit sensory potentiation and involvement of plastidial KEA transporters