scholarly journals A Turquoise Mutant Genetically Separates Expression of Genes Encoding Phycoerythrin and Its Associated Linker Peptides

2002 ◽  
Vol 184 (4) ◽  
pp. 962-970 ◽  
Author(s):  
Laura Ort Seib ◽  
David M. Kehoe

ABSTRACT During complementary chromatic adaptation (CCA), cyanobacterial light harvesting structures called phycobilisomes are restructured in response to ambient light quality shifts. Transcription of genes encoding components of the phycobilisome is differentially regulated during this process: red light activates cpcB2A2, whereas green light coordinately activates the cpeCDE and cpeBA operons. Three signal transduction components that regulate CCA have been isolated to date: a sensor-photoreceptor (RcaE) and two response regulators (RcaF and RcaC). Mutations in the genes encoding these components affect the accumulation of both cpcB2A2 and cpeBA gene products. We have isolated and characterized a new pigmentation mutant called Turquoise 1. We demonstrate that this mutant phenotype is due to a dramatic decrease in cpeBA transcript abundance and results from a lesion in the cpeR gene. However, in this mutant cpeCDE RNA levels remain near those found in wild-type cells. Our results show that the coordinate regulation of cpeBA and cpeCDE by green light can be uncoupled by the loss of CpeR, and we furnish the first genetic evidence that different regulatory mechanisms control these two operons. Sequence analysis of CpeR reveals that it shares limited sequence similarity to members of the PP2C class of protein serine/threonine phosphatases. We also demonstrate that cpeBA and cpeCDE retain light quality responsiveness in a mutant lacking the RcaE photoreceptor. This provides compelling evidence for the partial control of CCA through an as-yet-uncharacterized second light quality sensing system.

Biologia ◽  
2010 ◽  
Vol 65 (4) ◽  
Author(s):  
Bazyli Czeczuga ◽  
Ewa Czeczuga-Semeniuk ◽  
Adrianna Semeniuk

AbstractThe effect of light quality on the photosynthetic pigments as chromatic adaptation in 8 species of lichens were examined. The chlorophylls, carotenoids in 5 species with green algae as phycobionts (Cladonia mitis, Hypogymnia physodes, H. tubulosa var. tubulosa and subtilis, Flavoparmelia caperata, Xanthoria parietina) and the chlorophyll a, carotenoids and phycobiliprotein pigments in 3 species with cyanobacteria as photobionts (Peltigera canina, P. polydactyla, P. rufescens) were determined. The total content of photosynthetic pigments was calculated according to the formule and particular pigments were determined by means CC, TLC, HPLC and IEC chromatography. The total content of the photosynthetic pigments (chlorophylls, carotenoids) in the thalli was highest in red light (genus Peltigera), yellow light (Xanthoria parietina), green light (Cladonia mitis) and at blue light (Flavoparmelia caperata and both species of Hypogymnia). The biggest content of the biliprotein pigments at red and blue lights was observed. The concentration of C-phycocyanin increased at red light, whereas C-phycoerythrin at green light.In Trebouxia phycobiont of Hypogymnia and Nostoc photobiont of Peltigera species the presence of the phytochromes was observed.


Author(s):  
A. D. Boney ◽  
E. D. S. Corner

It was recently suggested (Boney & Corner, i960,1962a) that, contrary to the theory of complementary chromatic adaptation, the accessory pigment phycoerythrin might not be involved in photosynthesis by sporelings of the intertidal red alga Plumaria elegans (Bonnem) Schm. but is used primarily as a means of protecting the plant from excess green light in the wave-band 500–540 mμ. This work, however, was done with one species only, and concerning the wider question of marine red algae in general, it seemed possible that the role of phycoerythrin might vary with ecological distribution. Thus, plants completely submerged and thereby excluded from most red light would use their accessory pigments for photosynthesis (energizing chlorophyll a indirectly); but plants adapted to long periods of normal daylight would be similar to Plumaria in relying to a much greater extent on chlorophyll a alone for photosynthesis, and use their accessory pigments as protection against inhibitory green light.


Microbiology ◽  
2010 ◽  
Vol 156 (3) ◽  
pp. 731-741 ◽  
Author(s):  
Bagmi Pattanaik ◽  
Beronda L. Montgomery

We have characterized a Fremyella diplosiphon TonB protein (FdTonB) and investigated its function during complementary chromatic adaptation. Sequence similarity analysis of FdTonB (571 aa) led to identification of several conserved domains characteristic of TonB proteins, including an N-terminal transmembrane domain, a central proline-rich spacer and a C-terminal TonB-related domain (TBRD). We identified a novel glycine-rich domain containing (Gly-X) n repeats. To assess FdTonB function, we constructed a ΔtonB mutant through homologous recombination based upon truncation of the central proline-rich spacer, glycine-rich domain and TBRD. Our ΔtonB mutant exhibited an aberrant cellular morphology under green light, with expanded cell width compared to the parental wild-type (WT) strain. The cellular morphology of the ΔtonB mutant recovered upon WT tonB expression. Interestingly, tonB expression was found to be independent of RcaE. As ΔtonB and WT strains respond in the same way when grown under iron-replete versus iron-limited conditions, our results suggest that FdTonB is not involved in the classic TonB function of mediating cellular adaptation to iron limitation, but exhibits a novel function related to the photoregulation of cellular morphology in F. diplosiphon.


The study of phytochrome signalling has yielded a wealth of data describing both the perception of light by the receptor, and the terminal steps in phytochrome-regulated gene expression by a number of transcription factors. We are now focusing on establishing the intervening steps linking phytochrome photoactivation to gene expression, and the regulation and interactions of these signalling pathways. Recent work has utilized both a pharmacological approach in phototrophic soybean suspension cultures and microinjection techniques in tomato to establish three distinct phytochrome signal-transduction pathways: (i) a calcium-dependent pathway that regulates the expression of genes encoding the chlorophyll a/b binding protein ( CAB ) and other components of photosystem II; (ii) a cGMP-dependent pathway that regulates the expression of the gene encoding chalcone synthase ( CHS ) and the production of anthocyanin pigments; and (iii) a pathway dependent upon both calcium and cGMP that regulates the expression of genes encoding components of photosystem I and is necessary for the production of mature chloroplasts. To study the components and the regulation of phytochrome signal-transduction pathways, mutants with altered photomorphogenic responses have been isolated by a number of laboratories. However, with several possible exceptions, little real progress has been made towards the isolation of mutants in positive regulatory elements of the phytochrome signal-transduction pathway. We have characterized a novel phytochrome A (phyA)-mediated far-red light (FR) response in Arabidopsis seedlings which we are currently using to screen for specific phyA signal-transduction mutants.


2013 ◽  
Vol 48 (2) ◽  
pp. 105-111 ◽  
Author(s):  
Eleonora Gabryszewska ◽  
Ryszard Rudnicki

The effect of white, blue, green, red and UV + white light on the growth and development of shoots and roots of Gerbera jamesonii cv. Queen Rebecca in relation to the presence of kinetin or IAA were investigated. The highest number of axillary shoots was obtained in red and green light on the medium with 5 mg l<sup>-1</sup> kinetin. Also, green and red light markedly increased the number of leaves developed on the plantlets on the medium supplemented with kinetin. Light quality and IAA added to culture medium variously affected the development of root system: roots were regenerated under all light treatments, higher root number was recorded under red light when 5 mg l<sup>-1</sup> IAA was added to the media, the shortest roots were found in red light on the medium supplemented with IAA. The greatest fresh weight of shoots was found under white light on the medium with kinetin. Red light markedly decreased shoot fresh weight on hormone-free medium. Blue and white light caused increase in fresh weight of roots.


1991 ◽  
Vol 46 (7-8) ◽  
pp. 542-548 ◽  
Author(s):  
F. López-Figueroa

Abstract The chlorophyll synthesis in the brown algae Desmarestia aculeata is affected by light quality and by the nutrient state in the medium before the illumination. Pulses of 5 min of red, green and blue light together with 200 μM nitrate in plants growing under natural conditions deter­ mined similar induction of chlorophyll synthesis. However, when the plants were incubated previously under starvation conditions the light effect was different. The induction of chlorophyll synthesis was greater after blue and green light than after red light pulses. Red-light photoreceptor was only involved in the chlorophyll synthesis under no nutrient limitations and under starvation conditions after previous illumination with blue light followed by far-red light. The induction of chlorophyll synthesis by green and blue light pulses applied together with nitrate was greater when the algae were incubated in starvation conditions than in natural conditions (normal nutrient state). Because all light effects were partially reversed by far-red light the involvement of a phyto-chrome-like photoreceptor is proposed. In addition, a coaction between blue-and a green-light photoreceptors and phytochrome is suggested.


1986 ◽  
Vol 227 (1248) ◽  
pp. 381-393 ◽  

The influence of light quality on the growth and chlorophyll and phycobiliprotein composition of eight strains of planktonic blue-green algae has been investigated. Growth rate in chromatic (red, green, blue) light (12 μE m -2 s -1 ) (1 μE = 6 × 10 17 photons) is a general function of the light absorption capacity of the cell. In all strains examined growth rate is enhanced in red light, and in Oscillatoria redekei and Gloeotrichia echinulata CC1 it exceeds the maximum growth rate possible in white light of a higher photon flux density under otherwise similar experimental conditions. In green light the growth rate of six phycocyanin-rich strains is approximately 60–75% of that in white light (12 μE m -2 s -1 ), but growth rate is enhanced in O. agardhii 7821 and G. echinulata CC1, which synthesize the green-light-absorbing phycobiliprotein, phycoerythrin. With the exception of these two phycoerythrin-producing strains, incubation in blue light results in a pronounced reduction in growth rate, which in the majority of strains is associated with a specific decline in cell chlorophyll concentrations. In all strains cell chlorophyll and phycobiliprotein content is similar in both white and green light. Associated with the enhancement of growth rate in red light there is a general decline in cell pigment concentrations. An increase in the cell chlorophyll: phycobiliprotein ratio also occurs in a number of strains in red light. This qualitative variation in pigmentation occurs where growth rate is at or near its maximum rate and in Gloeotrichia echinulata CC1 is the result of a specific reduction in the rate of phycoerythrin synthesis. In contrast to other blue-green algae capable of chromatic adaptation, the modulation of phycoerythrin synthesis in this strain is influenced considerably by the photon flux density of red light.


2004 ◽  
Vol 51 (2) ◽  
pp. 567-577 ◽  
Author(s):  
Kazuki Terauchi ◽  
Beronda L. Montgomery ◽  
Arthur R. Grossman ◽  
J. Clark Lagarias ◽  
David M. Kehoe

1973 ◽  
Vol 58 (2) ◽  
pp. 419-435 ◽  
Author(s):  
Allen Bennett ◽  
Lawrence Bogorad

Fluorescent and red light environments generate greatly different patterns of pigmentation and morphology in Fremyella diplosiphon. Most strikingly, red-illuminated cultures contain no measurable C-phycoerythrin and have a mean filament length about 10 times shorter than fluorescent-illuminated cultures. C-phycoerythrin behaves as a photoinducible constituent of this alga. Spectrophotometric and immunochemical procedures were devised so that C-phycoerythrin metabolism could be studied quantitatively with [14C]-phenylalanine pulse-chased cultures. Transfer of red-illuminated cultures to fluorescent light initiates C-phycoerythrin production by essentially de novo synthesis. C-phycoerythrin is not degraded to any significant extent in cultures continuously illuminated with fluorescent light. Transfer of fluorescent-illuminated cultures to red light causes an abrupt cessation of C-phycoerythrin synthesis. The C-phycoerythrin content of cultures adapting to red light decreases and subsequently becomes constant. Loss of C-phycoerythrin is not brought about by metabolic degradation, but rather by a decrease in mean filament length which is effected by transcellular breakage. In this experimental system, light influences intracellular C-phycoerythrin levels by regulating the rate of synthesis of the chromoprotein.


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