Arabidopsis thaliana CYCLIC NUCLEOTIDE-GATED CHANNEL2 mediates extracellular ATP signal transduction in root epidermis.

Funder: Agence Nationale de la Recherche; Id: http://dx.doi.org/10.13039/501100001665Funder: Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada; Id: http://dx.doi.org/10.13039/501100002790Damage can be signalled by extracellular ATP (eATP) using plasma membrane (PM) receptors to effect cytosolic free calcium ion ([Ca2+ ]cyt ) increase as a second messenger. The downstream PM Ca2+ channels remain enigmatic. Here, the Arabidopsis thaliana Ca2+ channel subunit CYCLIC NUCLEOTIDE-GATED CHANNEL2 (CNGC2) was identified as a critical component linking eATP receptors to downstream [Ca2+ ]cyt signalling in roots. Extracellular ATP-induced changes in single epidermal cell PM voltage and conductance were measured electrophysiologically, changes in root [Ca2+ ]cyt were measured with aequorin, and root transcriptional changes were determined by quantitative real-time PCR. Two cngc2 loss-of-function mutants were used: cngc2-3 and defence not death1 (which expresses cytosolic aequorin). Extracellular ATP-induced transient depolarization of Arabidopsis root elongation zone epidermal PM voltage was Ca2+ dependent, requiring CNGC2 but not CNGC4 (its channel co-subunit in immunity signalling). Activation of PM Ca2+ influx currents also required CNGC2. The eATP-induced [Ca2+ ]cyt increase and transcriptional response in cngc2 roots were significantly impaired. CYCLIC NUCLEOTIDE-GATED CHANNEL2 is required for eATP-induced epidermal Ca2+ influx, causing depolarization leading to [Ca2+ ]cyt increase and damage-related transcriptional response

The roots of future rice harvests

The authors thank the Global Rice Science Partnership and Agropolis Fondation (Special grant n° 1400–009 and Rhizopolis grant n° 1001–005) benefiting from a national ANR Investissement d’Avenir” grant ANR-10-LABX-001-01) for supporting the workshop. They acknowledge the assistance of Nathalie Pivot, Cirad and Véronique Rafin, INRA in workshop organization. The root research at Cirad and University of Aberdeen is supported by the European Grant (FP7/2007-2013) under grant agreement n° 289300.27 EURoot “Enhancing resource Uptake from ROOTs under stress in cereal crops”. Research at IRRI is supported by the Generation Challenge Program and the Bill and Melinda Gates Foundation. J.X. is supported by the AcRF Tier 2 grant (MOE2009-T2-1-060) from the Ministry of Education of Singapore and National Research Foundation Singapore under its Competitive Research Programme (CRP Award No. NRF2010 NRF-CRP002-018). Doan Trung Luu is supported by the EU Marie Curie International Outgoing Fellowship 'ORYZAQUA – Cell Biology of Rice Aquaporins' (PIOF-GA-2011-300150). AP acknowledges the Generation Challenge Programme funded project “Targeting drought avoidance root traits to enhance rice productivity under water limited environments”. Financial support for A.G. Diedhiou was provided by the Université Cheikh Anta Diop (UCAD, VE12/13, CpVIII-Ar4 ) and GRISP. *This paper is dedicated to the late memory of Pr Ping Wu who passed away in a tragic car accident on June 12th, 2014.Peer reviewedPublisher PD

Arbetsplatser i Kortedala och Gårdsten : branschstruktur och lokaliseringsmönster i två bostadsområden i Göteborg /

<p><b>Shoot (A-C) and root (D-F) ion content for <i>HKT1;1</i> native overexpression lines.</b> Statistical significance was determined using Tukey’s HSD test between each line within treatments. Bars with the same letters indicate no significant difference (<i>p</i> < 0.05). Error bars represent standard error of the mean where n = 12–18 plants.</p

Electrophysiologie et physiologie moléculaire des transports membranaires chez les végétaux

Mes travaux s'inscrivent dans le domaine de l'électrophysiologie des transports membranaires (biophysique et physiologie des transports). En thèse, je caractérise, après expression dans l'ovocyte de xénope, l'un des premiers canaux K+ clonés chez les végétaux. En post-doc, à York, j'analyse la réponse à NaCl des stomates de deux espèces d'Aster, une halophyte et une glycophyte et je recherche des canaux impliqués dans la réponse adaptative observée chez la halophyte. A Cambridge, j'étudie chez le poil absorbant racinaire les canaux calciques actifs à l'extrémité apicale en croissance, impliqués dans la polarisation de la croissance. En temps qu'IE CNRS à Montpellier, je prends part à des programmes de physiologie moléculaire visant essentiellement à identifier la fonction de canaux potassiques de type Shaker chez Arabidopsis. Mon projet de recherche porte sur une famille de transporteurs de Na+ et K+, les HKT, chez le riz. Il a pour objectif d'analyser le rôle de ces transporteurs dans l'homéostasie potassique et sodique et la résistance de la plante au stress salin à l'aide d'une stratégie de biologie intégrée

Functional diversity of cation channels and transporters in rice

Functional diversity of cation channels and transporters in rice. 24 ème colloque Canaux Ionique

Cation channels in the Arabidopsis plasma membrane

In vivo analyses have identified different functional types of ion channels in various plant tissues and cells. The Arabidopsis genome contains similar to70 genes for ion channels, of which 57 might be cation-selective channels (K+, Ca2+ or poorly discriminating channels). Here, we describe the different families of (putative) cation channels: the Shakers, the two-P-domain and Kir K+ channels (encoded by the KCO genes), the cyclic-nucleotide-gated channels, the glutamate receptors, and the Ca2+ channel TPC1. We also compare molecular data with the data obtained in planta, which should lead to abetter understanding of the identity of these channels and provide clues about their roles in plant nutrition and cell signalling

Coupling of water and potassium ions in K(+) channels of the tonoplast of Chara

Electrokinetic measurements, of streaming potential, were carried out on an excised inside-out patch of the vacuolar membrane of Chara corallina. A water activity gradient was imposed across the patch membrane containing a single K(+) channel by addition of sorbitol to one side. Two different K(+) channels were found in the tonoplast. Their open channel conductance was investigated as a function of KCl concentration. They had a maximal open channel conductance of 247 and 173 pS, and an apparent affinity (K(M)) of 116 and 92 mM, respectively. Single-channel zero-current potentials were determined in the presence of an osmotic gradient, and dilution artifacts were corrected for by addition of valinomycin to the bath. Our results suggest that 29 water molecules were coupled to the transport of one K(+) ion in the large conductance K(+) channel which has a pore radius of ∼1.5 nm

Hydro-mineral nutrition and adaptation to abiotic stresses in rice: Analysis of root aquaporins and Na+/K+ transport systems

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