Effect of Low CO2 Growth on PSA E and DES 6 cDNAS in Chlamydomonas Reinhardtii

Somanchi, Aravind; Handley, Eric R.; Moroney, James V.

doi:10.1007/978-94-011-3953-3_814

Cited by 2 publications

(2 citation statements)

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“…The presence of acetate in the medium of light-grown C. reinhardtii is reported to down-regulate transcription of Lhcb genes (Kindle 1987). It was also reported that low levels of CO 2 up-regulate the transcription of Lhc genes (Somanchi et al 1998). Therefore, dierentially regulated transcription and expression of Lhcb genes would be expected when cells are grown under dierent carbon conditions.…”

Section: Introductionmentioning

confidence: 94%

Photosynthetic apparatus organization and function in the wild type and a chlorophyll b -less mutant of Chlamydomonas reinhardtii . Dependence on carbon source

Polle

Benemann

Tanaka

et al. 2000

Planta

127

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The assembly, organization and function of the photosynthetic apparatus was investigated in the wild type and a chlorophyll (Chl) b-less mutant of the unicellular green alga Chlamydomonas reinhardtii, generated via DNA insertional mutagenesis. Comparative analyses were undertaken with cells grown photoheterotrophically (acetate), photomixotrophically (acetate and HCO3-) or photoautotrophically (HCO3-). It is shown that lack of Chl b diminished the photosystem-II (PSII) functional Chl antenna size from 320 Chl (a and b) to about 95 Chl a molecules. However, the functional Chl antenna size of PSI remained fairly constant at about 290 Chl molecules, independent of the presence of Chl b. Western blot and kinetic analyses suggested the presence of inner subunits of the Chl a-b light-harvesting complex of PSII (LHCII) and the entire complement of the Chl a-b light-harvesting complex of PSI (LHCI) in the mutant. It is concluded that Chl a can replace Chl b in the inner subunits of the LHCII and in the entire complement of the LHCI. Growth of cells on acetate as the sole carbon source imposes limitations in the photon-use efficiency and capacity of photosynthesis. These are manifested as a lower quantum yield and lower light-saturated rate of photosynthesis, and as lower variable to maximal (Fv/Fmax) chlorophyll fluorescence yield ratios. This adverse effect probably originates because acetate shifts the oxidation-reduction state of the plastoquinone pool, and also because it causes a decrease in the amount and/or activity of Rubisco in the chloroplast. Such limitations are fully alleviated upon inclusion of an inorganic carbon source (e.g. bicarbonate) in the cell growth medium. Further, the work provides evidence to show that transformation of green algae can be used as a tool by which to generate mutants exhibiting a permanently truncated Chl antenna size and a higher (per Chl) photosynthetic productivity of the cells.

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Section: Introductionmentioning

confidence: 94%

Photosynthetic apparatus organization and function in the wild type and a chlorophyll b -less mutant of Chlamydomonas reinhardtii . Dependence on carbon source

Polle

Benemann

Tanaka

et al. 2000

Planta

127

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“…It has been previously proposed that CO 2 would somehow affect pigment synthesis (Garcı´a-Sa´nchez et al 1994) and photosynthetic apparatus organization (Polle et al 2000). It seems that CO 2 is involved in the transcription of genes of the light-harvesting complex (LHC; Somanchi et al 1998) but the functional meaning of such regulation is unknown. Differences in energy partitioning between photosystems at high or low CO 2 has also been reported (Satoh 2002).…”

Section: Introductionmentioning

confidence: 99%

Photon- and carbon-use efficiency in Ulva rigida at different CO 2 and N levels

Gordillo

Figueroa

Niell

2003

Planta

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The seaweed Ulva rigida C. Agardh (Chlorophyta) was cultured under two CO(2) conditions supplied through the air bubbling system: non-manipulated air and 1% CO(2)-enriched aeration. These were also combined with N sufficiency and N limitation, using nitrate as the only N source. High CO(2) in U. rigida led to higher growth rates without increasing the C fixed through photosynthesis under N sufficiency. Quantum yields for charge separation at photosystem II (PSII) reaction centres (phi(PSII)) and for oxygen evolution (phi(O2)) decreased at high CO(2) even in N-sufficient thalli. Cyclic electron flow around PSII as part of a photoprotection strategy accompanied by decreased antennae size was suspected. The new re-arrangement of the photosynthetic energy at high CO(2) included reduced investment in processes other than C fixation, as well as in carbon diverted to respiration. As a result, quantum yield for new biomass-C production (phi(growth)) increased. The calculation of the individual quantum yields for the different processes involved allowed the completion of the energy flow scheme through the cell from incident light to biomass production for each of the CO(2) and N-supply conditions studied.

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Effect of Low CO2 Growth on PSA E and DES 6 cDNAS in Chlamydomonas Reinhardtii

Cited by 2 publications

References 5 publications

Photosynthetic apparatus organization and function in the wild type and a chlorophyll b -less mutant of Chlamydomonas reinhardtii . Dependence on carbon source

Photosynthetic apparatus organization and function in the wild type and a chlorophyll b -less mutant of Chlamydomonas reinhardtii . Dependence on carbon source

Photon- and carbon-use efficiency in Ulva rigida at different CO 2 and N levels

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