Protein Structural Modeling and Transport Thermodynamics Reveal That Plant Cation-Chloride Cotransporters Mediate Potassium-Chloride Symport.

Plant cation-chloride cotransporters (CCCs) are proposed to be Na-K-2Cl transporting membrane proteins, although evolutionarily, they associate more closely with K-Cl cotransporters (KCCs). Here, we investigated grapevine ( L.) VvCCC using 3D protein modeling, bioinformatics, and electrophysiology with a heterologously expressed protein.

Expression of the grapevine anion transporter ALMT2 in Arabidopsis root decreases shoot Cl-/NO3- ratio under salt stress.

Grapevines (Vitis vinifera, Vvi) are economically important crop plants which, when challenged with salt (NaCl) in soil and/or irrigation water, tend to accumulate Na+ and Cl- in aerial tissues impacting yield, and berry acceptability for winemaking. Grapevine (Vitis spp.) rootstocks vary in their capacity for shoot Cl- exclusion.

Characterization of human aquaporin ion channels in a yeast expression system as a tool for novel ion channel discovery.

Aquaporin (AQP) channels found in all domains of life are transmembrane proteins which mediate passive transport of water, glycerol, signaling molecules, metabolites, and charged solutes. Discovery of new classes of ion-conducting AQP channels has been slow, likely reflecting time- and labor-intensive methods required for traditional electrophysiology. Work here defines a sensitive mass-throughput system for detecting AQP ion channels, identified by rescue of cell growth in the K+-transport-defective yeast strain CY162 following genetic complementation with heterologously expressed cation-permeable channels, using the well characterized human AQP1 channel for proof of concept.

Proteoliposomes reconstituted with human aquaporin-1 reveal novel single-ion-channel properties.

Human aquaporin 1 (hAQP1) forms homotetrameric channels that facilitate fluxes of water and small solutes across cell membranes. In addition to water channel activity, hAQP1 displays non-selective monovalent cation-channel activity gated by intracellular cyclic GMP. Dual water and ion-channel activity of hAQP1, thought to regulate cell shape and volume, could offer a target for novel therapeutics relevant to controlling cancer cell invasiveness.

Root-Specific Expression of VviNPF2.2 Modulates Shoot Anion Concentration in Transgenic .

Grapevines ( L., ) on their roots are generally sensitive to salt-forming ions, particularly chloride (Cl) when grown in saline environments. Grafting scions to Cl-excluding hybrid rootstocks reduces the impact of salinity.

Inhibition of the Aquaporin-1 Cation Conductance by Selected Furan Compounds Reduces Red Blood Cell Sickling.

In sickle cell disease (SCD), the pathological shift of red blood cells (RBCs) into distorted morphologies under hypoxic conditions follows activation of a cationic leak current (Psickle) and cell dehydration. Prior work showed sickling was reduced by 5-hydroxylmethyl-2-furfural (5-HMF), which stabilized mutant hemoglobin and also blocked the Psickle current in RBCs, though the molecular basis of this 5-HMF-sensitive cation current remained a mystery. Work here is the first to test the hypothesis that Aquaporin-1 (AQP1) cation channels contribute to the monovalent component of Psickle.

Soybean CHX-type ion transport protein GmSALT3 confers leaf Na exclusion via a root derived mechanism, and Cl exclusion via a shoot derived process.

Soybean (Glycine max) yields are threatened by multiple stresses including soil salinity. GmSALT3 (a cation-proton exchanger protein) confers net shoot exclusion for both Na and Cl and improves salt tolerance of soybean; however, how the ER-localized GmSALT3 achieves this is unknown. Here, GmSALT3's function was investigated in heterologous systems and near isogenic lines that contained the full-length GmSALT3 (NIL-T; salt-tolerant) or a truncated transcript Gmsalt3 (NIL-S; salt-sensitive).

Efficient CRISPR/Cas9-Mediated Knockout of an Endogenous Gene in T1 Progeny of Apomictic Enables New Strategies for Apomixis Gene Identification.

Most subgenus species are self-incompatible. Some undergo facultative apomixis where most seeds form asexually with a maternal genotype. Most embryo sacs develop by mitosis, without meiosis and seeds form without fertilization.

The grapevine NaE sodium exclusion locus encodes sodium transporters with diverse transport properties and localisation.

Grapevine (Vitis vinifera L.) is a valuable crop for human consumption and wine production, and is prone to suffering from salinity stress in arid regions or when exposed to low quality irrigation water. A previous study identified a quantitative trait locus (QTL) NaE, containing six High-affinity Potassium Transporter 1 genes, that was associated with shoot Na exclusion in grapevine.

Energy costs of salt tolerance in crop plants.

Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed.

Plant Cation-Chloride Cotransporters (CCC): Evolutionary Origins and Functional Insights.

Genomes of unicellular and multicellular green algae, mosses, grasses and dicots harbor genes encoding cation-chloride cotransporters (CCC). CCC proteins from the plant kingdom have been comparatively less well investigated than their animal counterparts, but proteins from both plants and animals have been shown to mediate ion fluxes, and are involved in regulation of osmotic processes. In this review, we show that CCC proteins from plants form two distinct phylogenetic clades (CCC1 and CCC2).

Functional differences in transport properties of natural HKT1;1 variants influence shoot Na exclusion in grapevine rootstocks.

Under salinity, Vitis spp. rootstocks can mediate salt (NaCl) exclusion from grafted V. vinifera scions enabling higher grapevine yields and production of superior wines with lower salt content.

Chloride: not simply a 'cheap osmoticum', but a beneficial plant macronutrient.

At macronutrient levels, chloride has positive effects on plant growth, which are distinct from its function in photosynthesis..

Non-selective cation channel activity of aquaporin AtPIP2;1 regulated by Ca and pH.

The aquaporin AtPIP2;1 is an abundant plasma membrane intrinsic protein in Arabidopsis thaliana that is implicated in stomatal closure, and is highly expressed in plasma membranes of root epidermal cells. When expressed in Xenopus laevis oocytes, AtPIP2;1 increased water permeability and induced a non-selective cation conductance mainly associated with Na . A mutation in the water pore, G103W, prevented both the ionic conductance and water permeability of PIP2;1.

SLAH1, a homologue of the slow type anion channel SLAC1, modulates shoot Cl- accumulation and salt tolerance in Arabidopsis thaliana.

Salinity tolerance is correlated with shoot chloride (Cl(-)) exclusion in multiple crops, but the molecular mechanisms of long-distance Cl(-) transport are poorly defined. Here, we characterize the in planta role of AtSLAH1 (a homologue of the slow type anion channel-associated 1 (SLAC1)). This protein, localized to the plasma membrane of root stelar cells, has its expression reduced by salt or ABA, which are key predictions for a protein involved with loading Cl(-) into the root xylem.

Identification of a Stelar-Localized Transport Protein That Facilitates Root-to-Shoot Transfer of Chloride in Arabidopsis.

Under saline conditions, higher plants restrict the accumulation of chloride ions (Cl(-)) in the shoot by regulating their transfer from the root symplast into the xylem-associated apoplast. To identify molecular mechanisms underpinning this phenomenon, we undertook a transcriptional screen of salt stressed Arabidopsis (Arabidopsis thaliana) roots. Microarrays, quantitative RT-PCR, and promoter-GUS fusions identified a candidate gene involved in Cl(-) xylem loading from the Nitrate transporter 1/Peptide Transporter family (NPF2.

Grapevine and Arabidopsis Cation-Chloride Cotransporters Localize to the Golgi and Trans-Golgi Network and Indirectly Influence Long-Distance Ion Transport and Plant Salt Tolerance.

Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. They are predicted to improve shoot salt exclusion by directly catalyzing the retrieval of sodium (Na(+)) and chloride (Cl(-)) ions from the root xylem. We investigated whether grapevine (Vitis vinifera [Vvi]) CCC has a role in salt tolerance by cloning and functionally characterizing the gene from the cultivar Cabernet Sauvignon.

Shoot chloride exclusion and salt tolerance in grapevine is associated with differential ion transporter expression in roots.

Background: Salt tolerance in grapevine is associated with chloride (Cl-) exclusion from shoots; the rate-limiting step being the passage of Cl- between the root symplast and xylem apoplast. Despite an understanding of the physiological mechanism of Cl- exclusion in grapevine, the molecular identity of membrane proteins that control this process have remained elusive. To elucidate candidate genes likely to control Cl- exclusion, we compared the root transcriptomes of three Vitis spp.

Protocol: optimising hydroponic growth systems for nutritional and physiological analysis of Arabidopsis thaliana and other plants.

Background: Hydroponic growth systems are a convenient platform for studying whole plant physiology. However, we found through trialling systems as they are described in the literature that our experiments were frequently confounded by factors that affected plant growth, including algal contamination and hypoxia. We also found the way in which the plants were grown made them poorly amenable to a number of common physiological assays.

Residency training: the King-Devick test and sleep deprivation: study in pre- and post-call neurology residents.

Objective: The current study investigates the effect of sleep deprivation on the speed and accuracy of eye movements as measured by the King-Devick (K-D) test, a <1-minute test that involves rapid number naming.

Methods: In this cohort study, neurology residents and staff from the University of Pennsylvania Health System underwent baseline followed by postcall K-D testing (n = 25); those not taking call (n = 10) also completed baseline and follow-up K-D testing. Differences in the times and errors between baseline and follow-up K-D scores were compared between the 2 groups.

Ganglion cell loss in relation to visual disability in multiple sclerosis.

Purpose: We used high-resolution spectral-domain optical coherence tomography (SD-OCT) with retinal segmentation to determine how ganglion cell loss relates to history of acute optic neuritis (ON), retinal nerve fiber layer (RNFL) thinning, visual function, and vision-related quality of life (QOL) in multiple sclerosis (MS).

Design: Cross-sectional study.

Participants: A convenience sample of patients with MS (n = 122; 239 eyes) and disease-free controls (n = 31; 61 eyes).