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Occurrence of Far-Red Light Photoacclimation (FaRLiP) in Diverse Cyanobacteria.

Gan F, Shen G, Bryant DA - Life (Basel) (2014)

Bottom Line: JSC-1.After acclimation all five strains could grow continuously in far-red light.We conclude that these photosynthetic gene clusters are diagnostic of the capacity to photoacclimate to and grow in far-red light.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA. fxg142@psu.edu.

ABSTRACT
Cyanobacteria have evolved a number of acclimation strategies to sense and respond to changing nutrient and light conditions. Leptolyngbya sp. JSC-1 was recently shown to photoacclimate to far-red light by extensively remodeling its photosystem (PS) I, PS II and phycobilisome complexes, thereby gaining the ability to grow in far-red light. A 21-gene photosynthetic gene cluster (rfpA/B/C, apcA2/B2/D2/E2/D3, psbA3/D3/C2/B2/ H2/A4, psaA2/B2/L2/I2/F2/J2) that is specifically expressed in far-red light encodes the core subunits of the three major photosynthetic complexes. The growth responses to far-red light were studied here for five additional cyanobacterial strains, each of which has a gene cluster similar to that in Leptolyngbya sp. JSC-1. After acclimation all five strains could grow continuously in far-red light. Under these growth conditions each strain synthesizes chlorophylls d, f and a after photoacclimation, and each strain produces modified forms of PS I, PS II (and phycobiliproteins) that absorb light between 700 and 800 nm. We conclude that these photosynthetic gene clusters are diagnostic of the capacity to photoacclimate to and grow in far-red light. Given the diversity of terrestrial environments from which these cyanobacteria were isolated, it is likely that FaRLiP plays an important role in optimizing photosynthesis in terrestrial environments.

No MeSH data available.


Related in: MedlinePlus

Absorption spectra of fractions from diethylaminoethyl (DEAE)-Sepharose chromatography of dissociated PBS isolated from F. thermalis PCC 7521 cells grown in far-red light (FRL). The buffer was 50 mM Tris-HCl at pH 7.0, and four fractions were eluted with 100, 140, 160, and 200 mM NaCl. Fraction E100 eluted with 100 mM NaCl (red line) has an absorption maximum at 576 nm and is highly enriched in phycoerythrocyanin [32]. Fraction E140 eluted with 140 mM NaCl (green line) has an absorption maximum at 616 nm and is highly enriched in phycocyanin. Fraction E160 eluted at 160 mM (blue line) has absorption maxima at 622, 651, and 707 nm. It is presently unclear whether this fraction is a mixture of proteins or whether this represents a component of the core substructure. Finally, fraction E-200 eluted with 200 mM NaCl (black line) has absorption maxima at 622 and 707 nm. This fraction resembles the spectrum of allophycocyanin-B [35] except that the long-wavelength absorption maximum is red-shifted by ~36 nm. See main text for additional details.
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life-05-00004-f007: Absorption spectra of fractions from diethylaminoethyl (DEAE)-Sepharose chromatography of dissociated PBS isolated from F. thermalis PCC 7521 cells grown in far-red light (FRL). The buffer was 50 mM Tris-HCl at pH 7.0, and four fractions were eluted with 100, 140, 160, and 200 mM NaCl. Fraction E100 eluted with 100 mM NaCl (red line) has an absorption maximum at 576 nm and is highly enriched in phycoerythrocyanin [32]. Fraction E140 eluted with 140 mM NaCl (green line) has an absorption maximum at 616 nm and is highly enriched in phycocyanin. Fraction E160 eluted at 160 mM (blue line) has absorption maxima at 622, 651, and 707 nm. It is presently unclear whether this fraction is a mixture of proteins or whether this represents a component of the core substructure. Finally, fraction E-200 eluted with 200 mM NaCl (black line) has absorption maxima at 622 and 707 nm. This fraction resembles the spectrum of allophycocyanin-B [35] except that the long-wavelength absorption maximum is red-shifted by ~36 nm. See main text for additional details.

Mentions: Phycobilisomes were isolated from F. thermalis PCC 7521 cells that had been grown in FRL, and fractions enriched in specific phycobiliproteins were isolated from dissociated phycobilisomes by DEAE-Sepharose chromatography at pH 7.0. Four fractions eluting at different sodium chloride concentrations (100 to 200 mM NaCl) were obtained, and the absorption spectra of these fractions are shown in Figure 7. The fractions eluting at 100 mM and 140 mM NaCl were highly enriched in phycoerythrocyanin (576 nm) and phycocyanin (616 nm), respectively [32]. The fraction eluted at 160 mM NaCl had absorption maxima at 620, 650, and 710 nm, and this fraction may either be a mixture of proteins or could be representative of allophycocyanin-like proteins derived from the core substructure. The fraction eluted with 200 mM NaCl is unlike any reported phycobiliprotein, although similar fractions have been obtained from Leptolyngbya JSC-1 cells grown in FRL [28]. This fraction had a broad absorption band with a maximal absorption at 622 nm and a very narrow and more intense absorption band with maximal absorption at 707 nm; the shape of the spectrum resembles that of allophycocyanin-B, which has maxima at 618 nm and 671 nm [35], except that the long-wavelength absorption band is red-shifted by ~36 nm. Very similar fractions were also observed for phycobiliproteins isolated from cells of Synechococcus sp. PCC 7335 grown in FRL, but no phycobiliproteins with absorption above 700 nm are present when cells of this strain are grown in WL or RL (see spectra in Figure 2A). These data show that, as previously observed for Leptolyngbya JSC-1 [28], phycobiliproteins comprising the core substructure are replaced and phycobilisomes remodeled in cells of F. thermalis PCC 7521 and Synechococcus sp. PCC 7335 undergoing FaRLiP.


Occurrence of Far-Red Light Photoacclimation (FaRLiP) in Diverse Cyanobacteria.

Gan F, Shen G, Bryant DA - Life (Basel) (2014)

Absorption spectra of fractions from diethylaminoethyl (DEAE)-Sepharose chromatography of dissociated PBS isolated from F. thermalis PCC 7521 cells grown in far-red light (FRL). The buffer was 50 mM Tris-HCl at pH 7.0, and four fractions were eluted with 100, 140, 160, and 200 mM NaCl. Fraction E100 eluted with 100 mM NaCl (red line) has an absorption maximum at 576 nm and is highly enriched in phycoerythrocyanin [32]. Fraction E140 eluted with 140 mM NaCl (green line) has an absorption maximum at 616 nm and is highly enriched in phycocyanin. Fraction E160 eluted at 160 mM (blue line) has absorption maxima at 622, 651, and 707 nm. It is presently unclear whether this fraction is a mixture of proteins or whether this represents a component of the core substructure. Finally, fraction E-200 eluted with 200 mM NaCl (black line) has absorption maxima at 622 and 707 nm. This fraction resembles the spectrum of allophycocyanin-B [35] except that the long-wavelength absorption maximum is red-shifted by ~36 nm. See main text for additional details.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390838&req=5

life-05-00004-f007: Absorption spectra of fractions from diethylaminoethyl (DEAE)-Sepharose chromatography of dissociated PBS isolated from F. thermalis PCC 7521 cells grown in far-red light (FRL). The buffer was 50 mM Tris-HCl at pH 7.0, and four fractions were eluted with 100, 140, 160, and 200 mM NaCl. Fraction E100 eluted with 100 mM NaCl (red line) has an absorption maximum at 576 nm and is highly enriched in phycoerythrocyanin [32]. Fraction E140 eluted with 140 mM NaCl (green line) has an absorption maximum at 616 nm and is highly enriched in phycocyanin. Fraction E160 eluted at 160 mM (blue line) has absorption maxima at 622, 651, and 707 nm. It is presently unclear whether this fraction is a mixture of proteins or whether this represents a component of the core substructure. Finally, fraction E-200 eluted with 200 mM NaCl (black line) has absorption maxima at 622 and 707 nm. This fraction resembles the spectrum of allophycocyanin-B [35] except that the long-wavelength absorption maximum is red-shifted by ~36 nm. See main text for additional details.
Mentions: Phycobilisomes were isolated from F. thermalis PCC 7521 cells that had been grown in FRL, and fractions enriched in specific phycobiliproteins were isolated from dissociated phycobilisomes by DEAE-Sepharose chromatography at pH 7.0. Four fractions eluting at different sodium chloride concentrations (100 to 200 mM NaCl) were obtained, and the absorption spectra of these fractions are shown in Figure 7. The fractions eluting at 100 mM and 140 mM NaCl were highly enriched in phycoerythrocyanin (576 nm) and phycocyanin (616 nm), respectively [32]. The fraction eluted at 160 mM NaCl had absorption maxima at 620, 650, and 710 nm, and this fraction may either be a mixture of proteins or could be representative of allophycocyanin-like proteins derived from the core substructure. The fraction eluted with 200 mM NaCl is unlike any reported phycobiliprotein, although similar fractions have been obtained from Leptolyngbya JSC-1 cells grown in FRL [28]. This fraction had a broad absorption band with a maximal absorption at 622 nm and a very narrow and more intense absorption band with maximal absorption at 707 nm; the shape of the spectrum resembles that of allophycocyanin-B, which has maxima at 618 nm and 671 nm [35], except that the long-wavelength absorption band is red-shifted by ~36 nm. Very similar fractions were also observed for phycobiliproteins isolated from cells of Synechococcus sp. PCC 7335 grown in FRL, but no phycobiliproteins with absorption above 700 nm are present when cells of this strain are grown in WL or RL (see spectra in Figure 2A). These data show that, as previously observed for Leptolyngbya JSC-1 [28], phycobiliproteins comprising the core substructure are replaced and phycobilisomes remodeled in cells of F. thermalis PCC 7521 and Synechococcus sp. PCC 7335 undergoing FaRLiP.

Bottom Line: JSC-1.After acclimation all five strains could grow continuously in far-red light.We conclude that these photosynthetic gene clusters are diagnostic of the capacity to photoacclimate to and grow in far-red light.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA. fxg142@psu.edu.

ABSTRACT
Cyanobacteria have evolved a number of acclimation strategies to sense and respond to changing nutrient and light conditions. Leptolyngbya sp. JSC-1 was recently shown to photoacclimate to far-red light by extensively remodeling its photosystem (PS) I, PS II and phycobilisome complexes, thereby gaining the ability to grow in far-red light. A 21-gene photosynthetic gene cluster (rfpA/B/C, apcA2/B2/D2/E2/D3, psbA3/D3/C2/B2/ H2/A4, psaA2/B2/L2/I2/F2/J2) that is specifically expressed in far-red light encodes the core subunits of the three major photosynthetic complexes. The growth responses to far-red light were studied here for five additional cyanobacterial strains, each of which has a gene cluster similar to that in Leptolyngbya sp. JSC-1. After acclimation all five strains could grow continuously in far-red light. Under these growth conditions each strain synthesizes chlorophylls d, f and a after photoacclimation, and each strain produces modified forms of PS I, PS II (and phycobiliproteins) that absorb light between 700 and 800 nm. We conclude that these photosynthetic gene clusters are diagnostic of the capacity to photoacclimate to and grow in far-red light. Given the diversity of terrestrial environments from which these cyanobacteria were isolated, it is likely that FaRLiP plays an important role in optimizing photosynthesis in terrestrial environments.

No MeSH data available.


Related in: MedlinePlus