scholarly journals Potential transceptor AtNRT1.13 modulates shoot architecture and flowering time in a nitrate-dependent manner

2021 ◽  
Author(s):  
Hui-Yu Chen ◽  
Shan-Hua Lin ◽  
Ling-Hsin Cheng ◽  
Jeng-Jong Wu ◽  
Yi-Chen Lin ◽  
...  
Keyword(s):  
Flowering Time ◽  
Nitrate Transport ◽  
Dependent Manner ◽  
Transport Activity ◽  
Node Number ◽  
Shoot Architecture ◽  
Glucuronidase Reporter ◽  
Uptake Activity ◽  
Delayed Flowering ◽  
Severe Growth

Abstract Compared with root development regulated by external nutrients, less is known about how internal nutrients are monitored to control plasticity of shoot development. In this study, we characterize an Arabidopsis thaliana transceptor, NRT1.13 (NPF4.4), of the NRT1/PTR/NPF family. Different from most NRT1 transporters, NRT1.13 does not have the conserved proline residue between transmembrane domains 10 and 11; an essential residue for nitrate transport activity in CHL1/NRT1.1/NPF6.3. As expected, when expressed in oocytes, NRT1.13 showed no nitrate transport activity. However, when Ser 487 at the corresponding position was converted back to proline, NRT1.13 S487P regained nitrate uptake activity, suggesting that wild-type NRT1.13 cannot transport nitrate but can bind it. Subcellular localization and β-glucuronidase reporter analyses indicated that NRT1.13 is a plasma membrane protein expressed at the parenchyma cells next to xylem in the petioles and the stem nodes. When plants were grown with a normal concentration of nitrate, nrt1.13 showed no severe growth phenotype. However, when grown under low-nitrate conditions, nrt1.13 showed delayed flowering, increased node number, retarded branch outgrowth, and reduced lateral nitrate allocation to nodes. Our results suggest that NRT1.13 is required for low-nitrate acclimation and that internal nitrate is monitored near the xylem by NRT1.13 to regulate shoot architecture and flowering time.

scholarly journals The KtrA and KtrE Subunits Are Required for Na+-Dependent K+ Uptake by KtrB across the Plasma Membrane in Synechocystis sp. Strain PCC 6803

2010 ◽  
Vol 192 (19) ◽  
pp. 5063-5070 ◽  
Author(s):  
Lalu Zulkifli ◽  
Masaro Akai ◽  
Asuka Yoshikawa ◽  
Mie Shimojima ◽  
Hiroyuki Ohta ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Homology Model ◽  
Atomic Scale ◽  
Site Directed Mutagenesis ◽  
Dependent Manner ◽  
Transport Activity ◽  
Charged Residues ◽  
Uptake Activity ◽  
Extracellular Side

ABSTRACT The Na+-dependent K+ uptake KtrABE system is essential for the adaptation of Synechocystis to salinity stress and high osmolality. While KtrB forms the K+-translocating pore, the role of the subunits KtrA and KtrE for Ktr function remains elusive. Here, we characterized the role of KtrA and KtrE in Ktr-mediated K+ uptake and in modulating Na+ dependency. Expression of KtrB alone in a K+ uptake-deficient Escherichia coli strain conferred low K+ uptake activity that was not stimulated by Na+. Coexpression of both KtrA and KtrE with KtrB increased the K+ transport activity in a Na+-dependent manner. KtrA and KtrE were found to be localized to the plasma membrane in Synechocystis. Site-directed mutagenesis was used to analyze the role of single charged residues in KtrB for Ktr function. Replacing negatively charged residues facing the extracellular space with residues of the opposite charge increased the apparent Km for K+ in all cases. However, none of the mutations eliminated the Na+ dependency of Ktr-mediated K+ transport. Mutations of residues on the cytoplasmic side had larger effects on K+ uptake activity than those of residues on the extracellular side. Further analysis revealed that replacement of R262, which is well conserved among Ktr/Trk/HKT transporters in the third extracellular loop, by Glu abolished transport activity. The atomic-scale homology model indicated that R262 might interact with E247 and D261. Based on these data, interaction of KtrA and KtrE with KtrB increased the K+ uptake rate and conferred Na+ dependency.

scholarly journals Corrigendum to: Potential transceptor AtNRT1.13 modulates shoot architecture and flowering time in a nitrate-dependent manner

2021 ◽  
Author(s):  
Hui-Yu Chen ◽  
Shan-Hua Lin ◽  
Ling-Hsin Cheng ◽  
Jeng-Jong Wu ◽  
Yi-Chen Lin ◽  
...  
Keyword(s):  
Flowering Time ◽  
Dependent Manner ◽  
Shoot Architecture

Characterization of Na(+)-H+ antiporter activity associated with human cheek epithelial cells

1994 ◽  
Vol 267 (1) ◽  
pp. C84-C93 ◽  
Author(s):  
E. J. McMurchie ◽  
S. L. Burnard ◽  
G. S. Patten ◽  
E. J. Lee ◽  
R. A. King ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Subjects ◽  
Maximum Velocity ◽  
Hill Coefficient ◽  
Transport Activity ◽  
Uptake Activity ◽  
Dimethyl Amiloride ◽  
Mouth Wash ◽  
Na Uptake

Na+ transport activity was characterized in human cheek epithelial cells obtained from normotensive adult subjects. The cells were isolated using a mouth-wash procedure and assayed for Na+ uptake using a radioactive (22Na+) rapid filtration assay. Cheek cells displayed proton-dependent Na+ uptake activity that was dependent on the magnitude of the externally directed proton gradient measured using the fluorescent probe 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein to determine intracellular pH. Amiloride, ethylisopropylamiloride (EIPA), 5-(N,N-dimethyl)-amiloride, 5-(N-methyl-N-isobutyl)-amiloride (MIA), and 5-(N,N-hexamethylene)-amiloride (NNHA) all inhibited proton-dependent Na+ uptake, with MIA, EIPA, and NNHA being the most potent. The Michaelis constant (Km) for extracellular Na+ was 5.7 mM, while the maximum velocity for Na(+)-H+ antiporter activity was 4.3 nmol Na+.mg protein-1.30s-1. The Km for intracellular H+ was 0.17 microM, with a Hill coefficient of 0.7. Stimulation by ouabain and inhibition by bumetanide of cheek cell proton-dependent Na+ uptake indicated only relatively low activities of Na(+)-K(+)-ATPase and Na(+)-K(+)-2Cl- cotransport, respectively. These results are consistent with the presence of Na(+)-H+ antiporter activity in cheek cells. Cheek cells therefore provide a convenient, relatively noninvasive source of tissue for examining Na(+)-H+ antiporter activity in human subjects.

scholarly journals A Composite Analysis of Flowering Time Regulation in Lettuce

2021 ◽  
Vol 12 ◽  
Author(s):  
Rongkui Han ◽  
Maria José Truco ◽  
Dean O. Lavelle ◽  
Richard W. Michelmore
Keyword(s):  
Flowering Time ◽  
Crop Production ◽  
Phenotypic Diversity ◽  
Model Organism ◽  
Leafy Vegetables ◽  
Vegetable Crops ◽  
Comprehensive Overview ◽  
Molecular Studies ◽  
Functional Inference ◽  
Delayed Flowering

Plants undergo profound physiological changes when transitioning from vegetative to reproductive growth. These changes affect crop production, as in the case of leafy vegetables. Lettuce is one of the most valuable leafy vegetable crops in the world. Past genetic studies have identified multiple quantitative trait loci (QTLs) that affect the timing of the floral transition in lettuce. Extensive functional molecular studies in the model organism Arabidopsis provide the opportunity to transfer knowledge to lettuce to explore the mechanisms through which genetic variations translate into changes in flowering time. In this review, we integrated results from past genetic and molecular studies for flowering time in lettuce with orthology and functional inference from Arabidopsis. This summarizes the basis for all known genetic variation underlying the phenotypic diversity of flowering time in lettuce and how the genetics of flowering time in lettuce projects onto the established pathways controlling flowering time in plants. This comprehensive overview reveals patterns across experiments as well as areas in need of further study. Our review also represents a resource for developing cultivars with delayed flowering time.

Copper Ion Inhibition of Electron Transport Activity in Sodium Chloride Washed Photosystem II Particle Is Partially Prevented by Calcium Ion

1996 ◽  
Vol 51 (3-4) ◽  
pp. 179-184 ◽  
Author(s):  
Surendra Chandra Sabat
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Calcium Ion ◽  
Electron Flow ◽  
Copper Ion ◽  
Dependent Manner ◽  
Transport Activity ◽  
Concentration Dependent Manner ◽  
Control Activity ◽  
Electron Transport Activity

Abstract The inhibitory effects of copper ion (Cu2+) on the photosynthetic electron transport func­tion was investigated both in NaCl washed (depleted in 17 and 23 kDa polypeptides) and native (unwashed) photosystem II membrane preparations from spinach (Beta vulgaris) chlo-roplasts. Copper in the range of 2.0 to 15 μᴍ strongly inhibited the electron flow from water to 2,6-dichlorobenzoquinone in NaCl washed particles in a concentration dependent manner. Com plete inhibition was noticed at 15 μᴍ Cu2+. Oppositely in native membranes, 15 μᴍ C u2+ inhibited only 10-12% of control activity. It was found that calcium ion (Ca2+) significantly reduced the Cu2+ inhibition of electron transport activity. The Ca2+ supported prevention of Cu2+ toxicity was specific to Ca2+. Further analysis indicated that both Cu2+ and Ca2+ act competitively. Since Ca2+ is known to have stimulating/stabilizing effect at the donor side of photosystem II, it is therefore suggested that Cu2+ in NaCl washed particles exerts its inhibi­tory effect(s) at the oxidizing side of photosystem stimulates/stabilizes the oxygen evolution.

scholarly journals Interaction Between Induced and Natural Variation at oil yellow1 Delays Reproductive Maturity in Maize

2019 ◽  
Vol 10 (2) ◽  
pp. 797-810
Author(s):  
Rajdeep S. Khangura ◽  
Bala P. Venkata ◽  
Sandeep R. Marla ◽  
Michael V. Mickelbart ◽  
Singha Dhungana ◽  
...  
Keyword(s):  
Flowering Time ◽  
Chlorophyll Content ◽  
Chlorophyll Biosynthesis ◽  
Wild Type ◽  
Reproductive Maturity ◽  
Magnesium Chelatase ◽  
Chlorophyll Contents ◽  
Delayed Flowering ◽  
Mapping Populations ◽  
Expression Polymorphism

We previously demonstrated that maize (Zea mays) locus very oil yellow1 (vey1) encodes a putative cis-regulatory expression polymorphism at the magnesium chelatase subunit I gene (aka oil yellow1) that strongly modifies the chlorophyll content of the semi-dominant Oy1-N1989 mutants. The vey1 allele of Mo17 inbred line reduces chlorophyll content in the mutants leading to reduced photosynthetic output. Oy1-N1989 mutants in B73 reached reproductive maturity four days later than wild-type siblings. Enhancement of Oy1-N1989 by the Mo17 allele at the vey1 QTL delayed maturity further, resulting in detection of a flowering time QTL in two bi-parental mapping populations crossed to Oy1-N1989. The near isogenic lines of B73 harboring the vey1 allele from Mo17 delayed flowering of Oy1-N1989 mutants by twelve days. Just as previously observed for chlorophyll content, vey1 had no effect on reproductive maturity in the absence of the Oy1-N1989 allele. Loss of chlorophyll biosynthesis in Oy1-N1989 mutants and enhancement by vey1 reduced CO2 assimilation. We attempted to separate the effects of photosynthesis on the induction of flowering from a possible impact of chlorophyll metabolites and retrograde signaling by manually reducing leaf area. Removal of leaves, independent of the Oy1-N1989 mutant, delayed flowering but surprisingly reduced chlorophyll contents of emerging leaves. Thus, defoliation did not completely separate the identity of the signal(s) that regulates flowering time from changes in chlorophyll content in the foliage. These findings illustrate the necessity to explore the linkage between metabolism and the mechanisms that connect it to flowering time regulation.

The effect of leaf removal on flowering time in subterranean clover

1970 ◽  
Vol 21 (6) ◽  
pp. 893 ◽  
Author(s):  
WJ Collins ◽  
Y Aitken
Keyword(s):  
Flowering Time ◽  
Subterranean Clover ◽  
Early Growth ◽  
Grazing Management ◽  
Flower Initiation ◽  
Leaf Removal ◽  
Main Shoot ◽  
Delayed Flowering ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

The removal of fully expanded leaves delayed flowering by up to 30 days in subterranean clover cv. Mt. Barker sown in winter at Melbourne (38�S.). This effect on flowering was attributable partly to a delay in flower initiation and partly to a slower rate of leaf appearance after flower initiation. Thus leaf removal may be added to the factors already known to influence flower initiation in subterranean clover. When plants were grown under a 24 hr photoperiod. leaf removal had no effect on flower initiation; the slight delay that leaf removal caused in flowering was therefore due entirely to its effect in reducing the rate of leaf appearance. In other experiments leaf removal delayed the time of flower initiation but had no effect on the rate of leaf appearance. The effect of leaf removal on the time of flowering on the main shoot in lateral-dominant plants (as occur in the field) was qualitatively the same as in plants from which the laterals had been removed. Grazing management of subterranean clover which results in severe defoliation during early growth may delay flowering to such an extent that seed production is reduced substantially, and persistence thereby prejudiced.

Treat and trick: common regulation and manipulation of sugar transporters during sink establishment by the plant and the pathogen

2020 ◽  
Vol 71 (14) ◽  
pp. 3930-3940
Author(s):  
Benjamin Pommerrenig ◽  
Christina Müdsam ◽  
Dominik Kischka ◽  
H Ekkehard Neuhaus
Keyword(s):  
Intracellular Transport ◽  
Sugar Transport ◽  
Transport Proteins ◽  
Dependent Manner ◽  
Transport Activity ◽  
Sugar Transporters ◽  
Dependent Processes ◽  
Sink Establishment ◽  
Source And Sink

Abstract Sugar transport proteins are crucial for the coordinated allocation of sugars. In this Expert View we summarize recent key findings of the roles and regulation of sugar transporters in inter- and intracellular transport by focusing on applied approaches, demonstrating how sucrose transporter activity may alter source and sink dynamics and their identities. The plant itself alters its sugar transport activity in a developmentally dependent manner to either establish or load endogenous sinks, for example, during tuber formation and filling. Pathogens represent aberrant sinks that trigger the plant to induce the same processes, resulting in loss of carbon assimilates. We explore common mechanisms of intrinsic, developmentally dependent processes and aberrant, pathogen-induced manipulation of sugar transport. Transporter activity may also be targeted by breeding or genetic modification approaches in crop plants to alter source and sink metabolism upon the overexpression or heterologous expression of these proteins. In addition, we highlight recent progress in the use of sugar analogs to study these processes in vivo.

scholarly journals A genetic framework for regulation and seasonal adaptation of shoot architecture in hybrid aspen

2020 ◽  
Vol 117 (21) ◽  
pp. 11523-11530 ◽  
Author(s):  
Jay P. Maurya ◽  
Pal C. Miskolczi ◽  
Sanatkumar Mishra ◽  
Rajesh Kumar Singh ◽  
Rishikesh P. Bhalerao
Keyword(s):  
Growth Control ◽  
Genetic Network ◽  
Dependent Manner ◽  
Hybrid Aspen ◽  
Seasonal Growth ◽  
Seasonal Adaptation ◽  
Antagonistic Action ◽  
Shoot Architecture ◽  
Terminal Flower 1 ◽  
Simultaneous Activation

Shoot architecture is critical for optimizing plant adaptation and productivity. In contrast with annuals, branching in perennials native to temperate and boreal regions must be coordinated with seasonal growth cycles. How branching is coordinated with seasonal growth is poorly understood. We identified key components of the genetic network that controls branching and its regulation by seasonal cues in the model tree hybrid aspen. Our results demonstrate that branching and its control by seasonal cues is mediated by mutually antagonistic action of aspen orthologs of the flowering regulatorsTERMINAL FLOWER 1(TFL1) andAPETALA1(LIKE APETALA 1/LAP1).LAP1promotes branching through local action in axillary buds.LAP1acts in a cytokinin-dependent manner, stimulating expression of the cell-cycle regulatorAIL1and suppressingBRANCHED1expression to promote branching. Short photoperiod and low temperature, the major seasonal cues heralding winter, suppress branching by simultaneous activation ofTFL1and repression of theLAP1pathway. Our results thus reveal the genetic network mediating control of branching and its regulation by environmental cues facilitating integration of branching with seasonal growth control in perennial trees.

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