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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: Leptolyngbya sp.JSC-1.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

Low-temperature (77 K) fluorescence emission spectra for four cyanobacterial strains grown in white light (WL) or far-red light (FRL). (A) Chr. thermalis PCC 7203; (B) Calothrix sp. PCC 7507; (C) F. thermalis PCC 7521; (D) Chlorogloeopsis sp. PCC 9212. The excitation wavelength was 440 nm, which predominantly excites Chls.
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life-05-00004-f006: Low-temperature (77 K) fluorescence emission spectra for four cyanobacterial strains grown in white light (WL) or far-red light (FRL). (A) Chr. thermalis PCC 7203; (B) Calothrix sp. PCC 7507; (C) F. thermalis PCC 7521; (D) Chlorogloeopsis sp. PCC 9212. The excitation wavelength was 440 nm, which predominantly excites Chls.

Mentions: Chls in cyanobacteria are mostly associated with PS I and PS II under nutrient-replete and moderate irradiance conditions. Low-temperature fluorescence emission spectroscopy was used to detect differences in the synthesis of photosynthetic complexes in cells grown in WL (or RL) and FRL conditions. As shown in Figure 6, the fluorescence emission maxima for PS I complexes in whole cells grown in WL had emission maxima at 720 nm for Chr. thermalis PCC 7203, 730 nm for Calothrix sp. PCC 7507 and F. thermalis PCC 7521, and 725 nm for Chlorogloeopsis sp. PCC 9212. As also observed in Leptolyngbya JSC-1 [28] and Synechococcus sp. PCC 7335 (Figure 2B), the amplitudes of the emission peaks from PS II at 683 and 695 nm in cells grown in WL were much smaller than that for PS I, which is expected because PS I binds the majority of the Chls in cyanobacteria [34]. The fluorescence emission spectra for cells grown in FRL had new, red-shifted emission peaks compared to cells grown in WL. For Calothrix sp. PCC 7507 and Chlorogloeopsis sp. PCC 9212, a major new emission peak occurred at 736 nm for the PS I complexes of these two strains. For Chr. thermalis PCC 7203 and Chlorogloeopsis sp. PCC 9212, two emission peaks with maxima at 736 and 750 nm were observed for PS I in cells grown in FRL. In these four strains, much lower fluorescence emission was observed between 680 and 700 nm for cells grown in FRL than for cells grown in WL. This observation implies that the PS II complexes of cells grown in FRL contain Chl d, Chl f, or both minor Chls (also see [28]). Thus, the five strains tested here can grow photoautotrophically in FRL, have enhanced absorption between 700 and 800 nm when grown in FRL, and synthesize Chls d and f in addition to Chl a when grown in FRL.


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

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

Low-temperature (77 K) fluorescence emission spectra for four cyanobacterial strains grown in white light (WL) or far-red light (FRL). (A) Chr. thermalis PCC 7203; (B) Calothrix sp. PCC 7507; (C) F. thermalis PCC 7521; (D) Chlorogloeopsis sp. PCC 9212. The excitation wavelength was 440 nm, which predominantly excites Chls.
© Copyright Policy
Related In: Results  -  Collection

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

life-05-00004-f006: Low-temperature (77 K) fluorescence emission spectra for four cyanobacterial strains grown in white light (WL) or far-red light (FRL). (A) Chr. thermalis PCC 7203; (B) Calothrix sp. PCC 7507; (C) F. thermalis PCC 7521; (D) Chlorogloeopsis sp. PCC 9212. The excitation wavelength was 440 nm, which predominantly excites Chls.
Mentions: Chls in cyanobacteria are mostly associated with PS I and PS II under nutrient-replete and moderate irradiance conditions. Low-temperature fluorescence emission spectroscopy was used to detect differences in the synthesis of photosynthetic complexes in cells grown in WL (or RL) and FRL conditions. As shown in Figure 6, the fluorescence emission maxima for PS I complexes in whole cells grown in WL had emission maxima at 720 nm for Chr. thermalis PCC 7203, 730 nm for Calothrix sp. PCC 7507 and F. thermalis PCC 7521, and 725 nm for Chlorogloeopsis sp. PCC 9212. As also observed in Leptolyngbya JSC-1 [28] and Synechococcus sp. PCC 7335 (Figure 2B), the amplitudes of the emission peaks from PS II at 683 and 695 nm in cells grown in WL were much smaller than that for PS I, which is expected because PS I binds the majority of the Chls in cyanobacteria [34]. The fluorescence emission spectra for cells grown in FRL had new, red-shifted emission peaks compared to cells grown in WL. For Calothrix sp. PCC 7507 and Chlorogloeopsis sp. PCC 9212, a major new emission peak occurred at 736 nm for the PS I complexes of these two strains. For Chr. thermalis PCC 7203 and Chlorogloeopsis sp. PCC 9212, two emission peaks with maxima at 736 and 750 nm were observed for PS I in cells grown in FRL. In these four strains, much lower fluorescence emission was observed between 680 and 700 nm for cells grown in FRL than for cells grown in WL. This observation implies that the PS II complexes of cells grown in FRL contain Chl d, Chl f, or both minor Chls (also see [28]). Thus, the five strains tested here can grow photoautotrophically in FRL, have enhanced absorption between 700 and 800 nm when grown in FRL, and synthesize Chls d and f in addition to Chl a when grown in FRL.

Bottom Line: Leptolyngbya sp.JSC-1.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