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Photosystem I cyclic electron flow via chloroplast NADH dehydrogenase-like complex performs a physiological role for photosynthesis at low light.

Yamori W, Shikanai T, Makino A - Sci Rep (2015)

Bottom Line: Although substantial progress has been made in understanding the structure of the chloroplast NADH dehydrogenase-like (NDH) complex, which mediates one route of the cyclic electron transport pathways, its physiological function is not well understood.In contrast, here it is shown that impairment of NDH-dependent cyclic electron flow in rice specifically causes a reduction in the electron transport rate through PS I (ETR I) at low light intensity with a concomitant reduction in CO2 assimilation rate, plant biomass and importantly, grain production.There was no effect on PS II function at low or high light intensity.

View Article: PubMed Central - PubMed

Affiliation: Center for Environment, Health and Field Sciences, Chiba University, 6-2-1 Kashiwa-no-ha, Kashiwa, Chiba 277-0882, Japan.

ABSTRACT
Cyclic electron transport around photosystem I (PS I) was discovered more than a half-century ago and two pathways have been identified in angiosperms. Although substantial progress has been made in understanding the structure of the chloroplast NADH dehydrogenase-like (NDH) complex, which mediates one route of the cyclic electron transport pathways, its physiological function is not well understood. Most studies focused on the role of the NDH-dependent PS I cyclic electron transport in alleviation of oxidative damage in strong light. In contrast, here it is shown that impairment of NDH-dependent cyclic electron flow in rice specifically causes a reduction in the electron transport rate through PS I (ETR I) at low light intensity with a concomitant reduction in CO2 assimilation rate, plant biomass and importantly, grain production. There was no effect on PS II function at low or high light intensity. We propose a significant physiological function for the chloroplast NDH at low light intensities commonly experienced during the reproductive and ripening stages of rice cultivation that have adverse effects crop yield.

No MeSH data available.


Related in: MedlinePlus

Effect of the crr6 defect on alleviation of photoinhibition.Effect of the crr6 defect on photoinhibition was examined. Leaves were exposed to strong light at 2,000 μmol photons m–2 s–1 at the corresponding temperature for 90 min. The fraction of active PS II (Fv/Fm) was measured after dark incubation for 30 min. Data represent means ± SE, n = 5. Significant differences among wild type plants, the control plants and the crr6 mutant are examined by Tukey-Kramer multiple comparison test (P < 0.05), but no significant differences were observed.
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f5: Effect of the crr6 defect on alleviation of photoinhibition.Effect of the crr6 defect on photoinhibition was examined. Leaves were exposed to strong light at 2,000 μmol photons m–2 s–1 at the corresponding temperature for 90 min. The fraction of active PS II (Fv/Fm) was measured after dark incubation for 30 min. Data represent means ± SE, n = 5. Significant differences among wild type plants, the control plants and the crr6 mutant are examined by Tukey-Kramer multiple comparison test (P < 0.05), but no significant differences were observed.

Mentions: The effect of the crr6 mutation on the Fv/Fm level was measured after exposure to strong light at 2,000 μmol photons m−2 s−1 for 90 min in plants grown at two different light intensities (Fig. 5). Before the strong light treatment, Fv/Fm was similar between the crr6 mutant and the control plants at any growth light intensities. The Fv/Fm level after the light stress was slightly lower in plants grown at low light intensity than those grown at high light intensity, but was similar between the crr6 mutant and the control plants irrespective of the growth light conditions.


Photosystem I cyclic electron flow via chloroplast NADH dehydrogenase-like complex performs a physiological role for photosynthesis at low light.

Yamori W, Shikanai T, Makino A - Sci Rep (2015)

Effect of the crr6 defect on alleviation of photoinhibition.Effect of the crr6 defect on photoinhibition was examined. Leaves were exposed to strong light at 2,000 μmol photons m–2 s–1 at the corresponding temperature for 90 min. The fraction of active PS II (Fv/Fm) was measured after dark incubation for 30 min. Data represent means ± SE, n = 5. Significant differences among wild type plants, the control plants and the crr6 mutant are examined by Tukey-Kramer multiple comparison test (P < 0.05), but no significant differences were observed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4566099&req=5

f5: Effect of the crr6 defect on alleviation of photoinhibition.Effect of the crr6 defect on photoinhibition was examined. Leaves were exposed to strong light at 2,000 μmol photons m–2 s–1 at the corresponding temperature for 90 min. The fraction of active PS II (Fv/Fm) was measured after dark incubation for 30 min. Data represent means ± SE, n = 5. Significant differences among wild type plants, the control plants and the crr6 mutant are examined by Tukey-Kramer multiple comparison test (P < 0.05), but no significant differences were observed.
Mentions: The effect of the crr6 mutation on the Fv/Fm level was measured after exposure to strong light at 2,000 μmol photons m−2 s−1 for 90 min in plants grown at two different light intensities (Fig. 5). Before the strong light treatment, Fv/Fm was similar between the crr6 mutant and the control plants at any growth light intensities. The Fv/Fm level after the light stress was slightly lower in plants grown at low light intensity than those grown at high light intensity, but was similar between the crr6 mutant and the control plants irrespective of the growth light conditions.

Bottom Line: Although substantial progress has been made in understanding the structure of the chloroplast NADH dehydrogenase-like (NDH) complex, which mediates one route of the cyclic electron transport pathways, its physiological function is not well understood.In contrast, here it is shown that impairment of NDH-dependent cyclic electron flow in rice specifically causes a reduction in the electron transport rate through PS I (ETR I) at low light intensity with a concomitant reduction in CO2 assimilation rate, plant biomass and importantly, grain production.There was no effect on PS II function at low or high light intensity.

View Article: PubMed Central - PubMed

Affiliation: Center for Environment, Health and Field Sciences, Chiba University, 6-2-1 Kashiwa-no-ha, Kashiwa, Chiba 277-0882, Japan.

ABSTRACT
Cyclic electron transport around photosystem I (PS I) was discovered more than a half-century ago and two pathways have been identified in angiosperms. Although substantial progress has been made in understanding the structure of the chloroplast NADH dehydrogenase-like (NDH) complex, which mediates one route of the cyclic electron transport pathways, its physiological function is not well understood. Most studies focused on the role of the NDH-dependent PS I cyclic electron transport in alleviation of oxidative damage in strong light. In contrast, here it is shown that impairment of NDH-dependent cyclic electron flow in rice specifically causes a reduction in the electron transport rate through PS I (ETR I) at low light intensity with a concomitant reduction in CO2 assimilation rate, plant biomass and importantly, grain production. There was no effect on PS II function at low or high light intensity. We propose a significant physiological function for the chloroplast NDH at low light intensities commonly experienced during the reproductive and ripening stages of rice cultivation that have adverse effects crop yield.

No MeSH data available.


Related in: MedlinePlus