scholarly journals Far-red light blocks greening of Arabidopsis seedlings via a phytochrome A-mediated change in plastid development.

1996 ◽  
Vol 8 (4) ◽  
pp. 601-615 ◽  
Author(s):  
S A Barnes ◽  
N K Nishizawa ◽  
R B Quaggio ◽  
G C Whitelam ◽  
N H Chua
Keyword(s):  
Red Light ◽  
Phytochrome A ◽  
Plastid Development

Far-Red Light Blocks Greening of Arabidopsis Seedlings via a Phytochrome A: Mediated Change in Plastid Development

1996 ◽  
Vol 8 (4) ◽  
pp. 601 ◽  
Author(s):  
Simon A. Barnes ◽  
Naoko K. Nishizawa ◽  
Ronaldo B. Quaggio ◽  
Garry C. Whitelam ◽  
Nam-Hai Chua
Keyword(s):  
Red Light ◽  
Phytochrome A ◽  
Plastid Development

Dynamics of the processes leading to the acquisition of sensitivity to very low fluence of photons inDatura feroxseeds

2013 ◽  
Vol 23 (4) ◽  
pp. 233-239
Author(s):  
Gabriela Alejandra Auge ◽  
Lucila de Miguel
Keyword(s):  
Physiological State ◽  
Red Light ◽  
Light Sensitivity ◽  
Growth Potential ◽  
Soil Tillage ◽  
Phytochrome A ◽  
Light Stimulation ◽  
Endosperm Weakening ◽  
Signalling Network ◽  
Stimulation Of

AbstractSoil tillage operations stimulate germination of buried seeds in cultivated lands, allowing them to perceive light as a germination-promoting factor. The time of burial and the effect of changing environmental factors affect the physiological state of the seeds, which may lead to an extreme light-sensitivity and very low fluence response (VLFR) through phytochrome A. This paper describes the influence of the progressive process of dormancy breakage, which is accompanied by the acquisition of extreme light-sensitivity, on processes associated with endosperm weakening and embryo growth potential in the VLFR-mediated promotion ofDatura feroxseed germination. Our results show that endosperm weakening is mainly limited by β-mannosidase enzyme activity after far-red light stimulation, which is highly dependent on the dormancy level of the seeds. In addition, stimulation of the embryo growth potential by far-red irradiation did not require an extreme light-sensitivity to very low fluence of photons to reach its maximum response, and it was not completely correlated with expansin gene expression in the embryo. Our work indicates that responses of endosperm weakening and embryo growth potential to far-red irradiation, dependent on dormancy level, have different requirements for stimulation by the signalling network initiated by phytochrome A during the course of the very low fluence response inDatura feroxseeds.

Peroxisome division and proliferation in plants

2010 ◽  
Vol 38 (3) ◽  
pp. 817-822 ◽  
Author(s):  
Kyaw Aung ◽  
Xinchun Zhang ◽  
Jianping Hu
Keyword(s):  
Red Light ◽  
Specific Protein ◽  
Development Research ◽  
Phytochrome A ◽  
Division 1 ◽  
Evolutionarily Conserved ◽  
Organelle Division ◽  
Specific Factors ◽  
Related Proteins ◽  
Peroxisome Division

Peroxisomes are eukaryotic organelles with crucial functions in development. Plant peroxisomes participate in various metabolic processes, some of which are co-operated by peroxisomes and other organelles, such as mitochondria and chloroplasts. Defining the complete picture of how these essential organelles divide and proliferate will be instrumental in understanding how the dynamics of peroxisome abundance contribute to changes in plant physiology and development. Research in Arabidopsis thaliana has identified several evolutionarily conserved major components of the peroxisome division machinery, including five isoforms of PEROXIN11 proteins (PEX11), two dynamin-related proteins (DRP3A and DRP3B) and two FISSION1 proteins (FIS1A/BIGYIN and FIS1B). Recent studies in our laboratory have also begun to uncover plant-specific factors. DRP5B is a dual-localized protein that is involved in the division of both chloroplasts and peroxisomes, representing an invention of the plant/algal lineage in organelle division. In addition, PMD1 (peroxisomal and mitochondrial division 1) is a plant-specific protein tail anchored to the outer surface of peroxisomes and mitochondria, mediating the division and/or positioning of these organelles. Lastly, light induces peroxisome proliferation in dark-grown Arabidopsis seedlings, at least in part, through activating the PEX11b gene. The far-red light receptor phyA (phytochrome A) and the transcription factor HYH (HY5 homologue) are key components in this signalling pathway. In summary, pathways for the division and proliferation of plant peroxisomes are composed of conserved and plant-specific factors. The sharing of division proteins by peroxisomes, mitochondria and chloroplasts is also suggesting possible co-ordination in the division of these metabolically associated plant organelles.

scholarly journals Phosphorylation of FAR-RED ELONGATED HYPOCOTYL1 Is a Key Mechanism Defining Signaling Dynamics of Phytochrome A under Red and Far-Red Light in Arabidopsis

2012 ◽  
Vol 24 (5) ◽  
pp. 1907-1920 ◽  
Author(s):  
Fang Chen ◽  
Xiarong Shi ◽  
Liang Chen ◽  
Mingqiu Dai ◽  
Zhenzhen Zhou ◽  
...  
Keyword(s):  
Red Light ◽  
Phytochrome A ◽  
Signaling Dynamics

scholarly journals Phytochrome A Function in Red Light Sensing

2007 ◽  
Vol 2 (5) ◽  
pp. 383-385 ◽  
Author(s):  
Keara A. Franklin ◽  
Garry C. Whitelam
Keyword(s):  
Red Light ◽  
Phytochrome A ◽  
Light Sensing

Physiology and plastid fine structure of deetiolating Lemna minor

1976 ◽  
Vol 54 (15) ◽  
pp. 1819-1826 ◽  
Author(s):  
Hugh Frick ◽  
Raymond F. Jones
Keyword(s):  
Higher Plants ◽  
Lemna Minor ◽  
Red Light ◽  
Acid Synthesis ◽  
Light Illumination ◽  
Fresh Weight ◽  
Plastid Development ◽  
Prolamellar Bodies ◽  
Rate Of Increase ◽  
Etiolated Plants

During the 12-h lag period in chlorophyll accumulation after the onset of white-light illumination of Lemna minor etiolated for 35 days, a rapid increase in visible fronds per culture occurred. This new frond production then assumed a log-linear rate of increase, and total protein per unit fresh weight came to parallel the rate of increase in fresh weight per plant. The ribosomal RNA content of 45-day-etiolated plants was deficient in 23S and 16S species compared with green plants. The prolamellar bodies of etioplasts were either tightly or loosely paracrystalline within the same cell; they were without extended perforate lamellae, which developed during far-red-light illumination even while prolamellar bodies persisted. The development of chloroplasts in deetiolating L. minor was typical of other higher plants. The developmental sequence in green Lemna included proplastid to deeply stacked granal chloroplast within several millimetres. Plastid profiles suggestive of division configurations occurred only in primordial cells of green and etiolated plants. The relatively small numbers of plastids in any given stage of differentiation may account for the sensitivity of plastid development to inhibitors of protein and nucleic acid synthesis.

scholarly journals Nucleoside diphosphate kinase isoforms regulated by phytochrome A isolated from oat coleoptiles.

2009 ◽  
Vol 56 (1) ◽  
Author(s):  
Anna Hetmann ◽  
Stanisław Kowalczyk
Keyword(s):  
Microsomal Fraction ◽  
Red Light ◽  
Nucleoside Diphosphate Kinase ◽  
Nuclear Fraction ◽  
Phytochrome A ◽  
Cell Nuclei ◽  
Native Form ◽  
Immunochemical Method ◽  
Sds Page ◽  
Molecular Masses

Nucleoside diphosphate kinase (NDPK) (EC 2.7.4.6), the enzyme transferring the phosphate residue from ATP to nucleoside diphosphates, is localized mainly in the cytoplasm and mitochondria and in smaller amounts in cell nuclei and the microsomal fraction. Exposure of etiolated oat seedlings to red light causes an increase of the enzyme activity by about 42% in nuclear fraction, 7% in etioplastic and 14% in postetioplastic fraction. Endogenous phytochrome A, as visualized by an immunochemical method, translocates from the cytoplasm into the nucleus upon red, far-red or white light activation. Nuclei purified from oat seedlings contain two, and the postnuclear fraction four easily separated forms of NDPK. One of the nuclear isoforms (I(n)) and one isoform isolated from the postnuclear fraction (II(pn)) are activated by red light in the presence of phytochrome A purified from etiolated oat coleoptiles. Both phytochrome A-activated NDPKs purified to electrophoretic homogeneity have the same molecular mass (17-18 kDa) determined by SDS/PAGE. Both enzymes in the native form have similar molecular masses (71 and 63 kDa).

Phytochromes and seed germination

1998 ◽  
Vol 8 (3) ◽  
pp. 317-329 ◽  
Author(s):  
Jorge J. Casal ◽  
Rodolfo A. Sánchez
Keyword(s):  
Seed Germination ◽  
Red Light ◽  
High Irradiance ◽  
Phytochrome B ◽  
Phytochrome A ◽  
Germination Inhibition ◽  
Growth Capacity ◽  
Small Family ◽  
Recent Advances ◽  
Signalling Process

AbstractThe control of seed germination by red and far-red light is one of the earliest documented phytochrome-mediated processes Phytochrome is now known to be a small family of photoreceptors whose apoproteins are encoded by different genes Phytochrome B (phyB) is present in dry seeds and affects germination of dark imbibed seeds but other phytochromes could also be involved Phytochrome A (phyA) appears after several hours of imbibition and mediates very-low-fluence responses PhyB and other phytochromes different from phyA mediate the classical low-fluence responses The phytochrome involved in high-irradiance responses of seed germination (inhibition of germination under continuous far-red) has not been unequivocally established, although phyA is the most likely candidate Phytochrome can affect embryo growth capacity and/or the constraint imposed by the tissues surrounding the embryo At least in some species, gibberellins participate in the signalling process In the field, phyA has been implicated in the perception of light during soil cultivations, and phyB would be involved in the perception of red/far-red ratios associated with the presence of gaps in the canopy This review describes recent advances in phytochrome research, particularly those derived from the analysis of germination in specific mutants, and their connection with traditional observations on phytochrome control of seed germination

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