scholarly journals Cell growth defect factor 1 is crucial for the plastid import of NADPH:protochlorophyllide oxidoreductase A in Arabidopsis thaliana

2015 ◽  
Vol 112 (18) ◽  
pp. 5838-5843 ◽  
Author(s):  
Steffen Reinbothe ◽  
John Gray ◽  
Sachin Rustgi ◽  
Diter von Wettstein ◽  
Christiane Reinbothe
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Growth ◽  
Protein Translocation ◽  
Higher Plants ◽  
Chlorophyll Biosynthesis ◽  
Growth Defect ◽  
Nadph:Protochlorophyllide Oxidoreductase ◽  
Photosynthetic Organisms ◽  
Plastid Envelope ◽  
A Cell

Tetrapyrroles such as chlorophyll, heme, and bacteriochlorophyll play fundamental roles in the energy absorption and transduction of all photosynthetic organisms. They are synthesized via a complex pathway taking place in chloroplasts. Chlorophyll biosynthesis in angiosperms involves 16 steps of which only one is light-requiring and driven by the NADPH:protochlorophyllide oxidoreductase (POR). Three POR isoforms have been identified in Arabidopsis thaliana—designated PORA, PORB, and PORC—that are differentially expressed in etiolated, light-exposed, and light-adapted plants. All three isoforms are encoded by nuclear genes, are synthesized as larger precursors in the cytosol (pPORs), and are imported posttranslationally into the plastid compartment. Import of the precursor to the dark-specific isoform PORA (pPORA) is protochlorophyllide (Pchlide)-dependent and due to the operation of a unique translocon complex dubbed PTC (Pchlide-dependent translocon complex) in the plastid envelope. Here, we identified a ∼30-kDa protein that participates in pPORA import. The ∼30-kDa protein is identical to the previously identified CELL GROWTH DEFECT FACTOR 1 (CDF1) in Arabidopsis that is conserved in higher plants and Synechocystis. CDF1 operates in pPORA import and stabilization and hereby acts as a chaperone for PORA protein translocation. CDF1 permits tight interactions between Pchlide synthesized in the plastid envelope and the importing PORA polypeptide chain such that no photoexcitative damage occurs through the generation of singlet oxygen operating as a cell death inducer. Together, our results identify an ancient mechanism dating back to the endosymbiotic origin of chloroplasts as a key element of Pchlide-dependent pPORA import.

scholarly journals Cdk1-dependent control of membrane-trafficking dynamics

2012 ◽  
Vol 23 (17) ◽  
pp. 3336-3347 ◽  
Author(s):  
Derek McCusker ◽  
Anne Royou ◽  
Christophe Velours ◽  
Douglas Kellogg
Keyword(s):  
Cell Growth ◽  
Cell Surface ◽  
Membrane Trafficking ◽  
Cell Cycle Progression ◽  
Secretory Pathway ◽  
Surface Growth ◽  
Growth Defect ◽  
Actin Depolymerization ◽  
Polarized Cell Growth ◽  
A Cell

Cyclin-dependent kinase 1 (Cdk1) is required for initiation and maintenance of polarized cell growth in budding yeast. Cdk1 activates Rho-family GTPases, which polarize the actin cytoskeleton for delivery of membrane to growth sites via the secretory pathway. Here we investigate whether Cdk1 plays additional roles in the initiation and maintenance of polarized cell growth. We find that inhibition of Cdk1 causes a cell surface growth defect that is as severe as that caused by actin depolymerization. However, unlike actin depolymerization, Cdk1 inhibition does not result in a massive accumulation of intracellular secretory vesicles or their cargoes. Analysis of post-Golgi vesicle dynamics after Cdk1 inhibition demonstrates that exocytic vesicles are rapidly mistargeted away from the growing bud, possibly to the endomembrane/vacuolar system. Inhibition of Cdk1 also causes defects in the organization of endocytic and exocytic zones at the site of growth. Cdk1 thus modulates membrane-trafficking dynamics, which is likely to play an important role in coordinating cell surface growth with cell cycle progression.

scholarly journals Chlorophyll Biosynthesis in a Cell-free System from Higher Plants

1971 ◽  
Vol 47 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Constantin A. Rebeiz ◽  
Paul A. Castelfranco
Keyword(s):  
Higher Plants ◽  
Chlorophyll Biosynthesis ◽  
Free System ◽  
Cell Free System ◽  
A Cell

scholarly journals A GATA Transcription Factor from Soybean (Glycine max) Regulates Chlorophyll Biosynthesis and Suppresses Growth in the Transgenic Arabidopsis thaliana

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1036 ◽  
Author(s):  
Chanjuan Zhang ◽  
Yi Huang ◽  
Zhiyuan Xiao ◽  
Hongli Yang ◽  
Qingnan Hao ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Glycine Max ◽  
Plant Growth ◽  
Transgenic Arabidopsis ◽  
Higher Plants ◽  
Chlorophyll Biosynthesis ◽  
Growth And Yield ◽  
Luciferase Reporter ◽  
Gata Transcription Factor ◽  
Dual Luciferase Reporter Assay

Chlorophyll plays an essential role in photosynthetic light harvesting and energy transduction in green tissues of higher plants and is closely related to photosynthesis and crop yield. Identification of transcription factors (TFs) involved in regulating chlorophyll biosynthesis is still limited in soybean (Glycine max), and the previously identified GmGATA58 is suggested to potentially modulate chlorophyll and nitrogen metabolisms, but its complete function is still unknown. In this study, subcellular localization assay showed that GmGATA58 was localized in the nucleus. Histochemical GUS assay and qPCR assay indicated that GmGATA58 was mainly expressed in leaves and responded to nitrogen, light and phytohormone treatments. Overexpression of GmGATA58 in the Arabidopsis thaliana ortholog AtGATA21 (gnc) mutant complemented the greening defect, while overexpression in Arabidopsis wild-type led to increasing chlorophyll content in leaves through up-regulating the expression levels of the large of chlorophyll biosynthetic pathway genes, but suppressing plant growth and yield, although the net photosynthetic rate was slightly improved. Dual-luciferase reporter assay also supported that GmGATA58 activated the transcription activities of three promoters of key chlorophyll biosynthetic genes of soybean in transformed protoplast of Arabidopsis. It is concluded that GmGATA58 played an important role in regulating chlorophyll biosynthesis, but suppressed plant growth and yield in transgenic Arabidopsis.

Utilization of a hydrate cellulose film for investigation of Arabidopsis thaliana L. root system growth and development

2020 ◽  
Vol 36 (1) ◽  
pp. 36-43
Author(s):  
I.O. Konovalova ◽  
T.N. Kudelina ◽  
S.O. Smolyanina ◽  
A.I. Lilienberg ◽  
T.N. Bibikova
Keyword(s):  
Arabidopsis Thaliana ◽  
Root System ◽  
Life Support ◽  
Higher Plants ◽  
Plant Root ◽  
Lateral Roots ◽  
Basic Research ◽  
Cellulose Film ◽  
A New Technique ◽  
Basic Research Project

A new technique for Arabidopsis thaliana cultivation has been proposed that combines the use of a phytogel-based nutrient medium and a hydrophilic membrane of hydrate cellulose film, separating the root system of the plant from the medium thickness. Growth rates of both main and lateral roots were faster in the plants cultivated on the surface of hydrate cellulose film than in the plants grown in the phytogel volume. The location of the root system on the surface of the transparent hydrate film simplifies its observation and analysis and facilitates plant transplantation with preservation of the root system configuration. The proposed technique allowed us to first assess the effect of exogenous auxin on the growth of lateral roots at the 5-6 developmental stage. methods to study plant root systems, hydrate cellulose film, A. thaliana, lateral roots, differential root growth rate, auxin The work was financially supported by the Russian Foundation for Basic Research (Project Bel_mol_a 19-54-04015) and the basic topic of the Russian Academy of Sciences - IBMP RAS «Regularities of the Influence of Extreme Environmental Factors on the Processes of Cultivation of Higher Plants and the Development of Japanese Quail Tissues at Different Stages of its Ontogenesis under the Conditions of Regenerative Life Support Systems».

Freezing

2017 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Thermal Hysteresis ◽  
Higher Plants ◽  
Terrestrial Environment ◽  
Cold Temperatures ◽  
Cellular Dehydration ◽  
A Cell ◽  
Unicellular Organisms ◽  
Cell Cytosol ◽  
Freezing Temperatures ◽  
Multicellular Organisms

Freezing is a widespread ecological challenge, affecting organisms in over half the terrestrial environment as well as both polar seas. With very few exceptions, if a cell freezes internally, it dies. Polar teleost fish in shallow waters avoid freezing by synthesising a range of protein or glycoprotein antifreezes. Terrestrial organisms are faced with a far greater thermal challenge, and exhibit a more complex array of responses. Unicellular organisms survive freezing temperatures by preventing ice nucleating within the cytosol, and tolerating the cellular dehydration and membrane disruption that follows from ice forming in the external environment. Multicellular organisms survive freezing temperatures by manipulating the composition of the extracellular body fluids. Terrestrial organisms may freeze at high subzero temperatures, often promoted by ice nucleating proteins, and small molecular mass cryoprotectants (often sugars and polyols) moderate the osmotic stress on cells. A range of chaperone proteins (dehydrins, LEA proteins) help maintain the integrity of membranes and macromolecules. Thermal hysteresis (antifreeze) proteins prevent damaging recrystallisation of ice. In some cases arthropods and higher plants prevent freezing in their extracellular fluids and survive by supercooling. Vitrification of extracellular water, or of the cell cytosol, may be a more widespread response to very cold temperatures than recognised to date.

scholarly journals Putrescine, a Cell Growth Factor

Nature ◽  
1972 ◽  
Vol 235 (5338) ◽  
pp. 366-366
Keyword(s):  
Growth Factor ◽  
Cell Growth ◽  
A Cell

scholarly journals ATP compartmentation in plastids and cytosol ofArabidopsis thalianarevealed by fluorescent protein sensing

2018 ◽  
Vol 115 (45) ◽  
pp. E10778-E10787 ◽  
Author(s):  
Chia Pao Voon ◽  
Xiaoqian Guan ◽  
Yuzhe Sun ◽  
Abira Sahu ◽  
May Ngor Chan ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Fluorescent Protein ◽  
Higher Plants ◽  
Electron Flow ◽  
Cyclic Electron Flow ◽  
Linear Electron ◽  
Protein Sensing ◽  
Atp Production ◽  
Respiratory Inhibitors ◽  
Sensor Protein

Matching ATP:NADPH provision and consumption in the chloroplast is a prerequisite for efficient photosynthesis. In terms of ATP:NADPH ratio, the amount of ATP generated from the linear electron flow does not meet the demand of the Calvin–Benson–Bassham (CBB) cycle. Several different mechanisms to increase ATP availability have evolved, including cyclic electron flow in higher plants and the direct import of mitochondrial-derived ATP in diatoms. By imaging a fluorescent ATP sensor protein expressed in livingArabidopsis thalianaseedlings, we found that MgATP2−concentrations were lower in the stroma of mature chloroplasts than in the cytosol, and exogenous ATP was able to enter chloroplasts isolated from 4- and 5-day-old seedlings, but not chloroplasts isolated from 10- or 20-day-old photosynthetic tissues. This observation is in line with the previous finding that the expression of chloroplast nucleotide transporters (NTTs) inArabidopsismesophyll is limited to very young seedlings. Employing a combination of photosynthetic and respiratory inhibitors with compartment-specific imaging of ATP, we corroborate the dependency of stromal ATP production on mitochondrial dissipation of photosynthetic reductant. Our data suggest that, during illumination, the provision and consumption of ATP:NADPH in chloroplasts can be balanced by exporting excess reductants rather than importing ATP from the cytosol.

scholarly journals Dissecting and modeling zeaxanthin- and lutein-dependent nonphotochemical quenching in Arabidopsis thaliana

2017 ◽  
Vol 114 (33) ◽  
pp. E7009-E7017 ◽  
Author(s):  
Michelle Leuenberger ◽  
Jonathan M. Morris ◽  
Arnold M. Chan ◽  
Lauriebeth Leonelli ◽  
Krishna K. Niyogi ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Light Intensity ◽  
Vascular Plants ◽  
Single Photon ◽  
Photon Counting ◽  
Nonphotochemical Quenching ◽  
Light Acclimation ◽  
Single Photon Counting ◽  
Photosynthetic Organisms ◽  
Psbs Protein

Photosynthetic organisms use various photoprotective mechanisms to dissipate excess photoexcitation as heat in a process called nonphotochemical quenching (NPQ). Regulation of NPQ allows for a rapid response to changes in light intensity and in vascular plants, is primarily triggered by a pH gradient across the thylakoid membrane (∆pH). The response is mediated by the PsbS protein and various xanthophylls. Time-correlated single-photon counting (TCSPC) measurements were performed on Arabidopsis thaliana to quantify the dependence of the response of NPQ to changes in light intensity on the presence and accumulation of zeaxanthin and lutein. Measurements were performed on WT and mutant plants deficient in one or both of the xanthophylls as well as a transgenic line that accumulates lutein via an engineered lutein epoxide cycle. Changes in the response of NPQ to light acclimation in WT and mutant plants were observed between two successive light acclimation cycles, suggesting that the character of the rapid and reversible response of NPQ in fully dark-acclimated plants is substantially different from in conditions plants are likely to experience caused by changes in light intensity during daylight. Mathematical models of the response of zeaxanthin- and lutein-dependent reversible NPQ were constructed that accurately describe the observed differences between the light acclimation periods. Finally, the WT response of NPQ was reconstructed from isolated components present in mutant plants with a single common scaling factor, which enabled deconvolution of the relative contributions of zeaxanthin- and lutein-dependent NPQ.

scholarly journals Genetic fine-structure of the GA-1 locus in the higher plant Arabidopsis thaliana (L.) Heynh

1983 ◽  
Vol 41 (1) ◽  
pp. 57-68 ◽  
Author(s):  
M. Koornneef ◽  
J. Van Eden ◽  
C. J. Hanhart ◽  
A. M. M. De Jongh
Keyword(s):  
Arabidopsis Thaliana ◽  
Fine Structure ◽  
Higher Plants ◽  
Wild Type ◽  
Higher Plant ◽  
Selfed Progeny ◽  
Intragenic Deletion ◽  
Genetic Length ◽  
Genetic Fine Structure ◽  
Half Diallel

SUMMARYNon-germinating gibberellin (GA) responsive mutants are a powerful tool to study genetic fine structure in higher plants. Nine alleles (EMS-and fast neutron-induced) of the ga-1 locus of Arabidopsis thaliana were tested in a complete half-diallel. No wild type ‘recombinants’ were found in the selfed progeny of 9 homoallelic combinations (in total 3 × 105 plants); in the progenies from the 36 selfed hetero allelics the wild type frequency ranged from zero to 6·6 × 10−4. These frequencies allowed the construction of an internally consistent map for five different sites representing eight alleles. The ninth allele covered three sites and thus behaved like an intragenic deletion. The estimate of the total genetic length of the ga-1 locus was 0·07 cM. The order of the sites was also clearly reflected by the association with proximal outside markers. On the assumption that wild type gametes predominantly arise from reciprocal events, it was shown that a cross-over within the ga-1 locus leads to positive interference in the adjacent region.The results are discussed with respect to the mutagen used, the frequencies found in other plant and Drosophila genes, and the possible occurrence of gene conversion.

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