Os08g0566600

The rice Os08g0566600 was reported as PGR5 in 2012 by researchers from Japan.

Annotated Information

Gene Symbol

• Os08g0566600 <=> OsPGR5,PGR5

Function

• The PGR5 (PROTON GRADIENT REGULATION 5) in Arabidopsis is required for PSI cyclic electron transport.
• The rice PGR5 is required for ferredoxin (Fd)-dependent plastoquinone (PQ) reduction in ruptured chloroplasts of rice.

Phenotypic analysis

• In three PGR5 knockdown (KD) lines, the PGR5 protein level was reduced to 5–8% of that in the wild type, resulting in a 50% reduction in PGRL1 (PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE 1) protein levels.
• In ruptured chloroplasts, ferredoxin-dependent plastoquinone reduction activity was partially impaired; the phenotype was mimicked by addition of antimycin A to wild-type chloroplasts.
• As occurred in the Arabidopsis pgr5 mutant, non-photochemical quenching of Chl fluorescence (NPQ) induction was impaired in the leaves, but the electron transport rate (ETR) was only mildly affected at high light intensity.
• The P700+ level was reduced even at low light intensity, suggesting that the PGR5 function was severely disturbed as in the Arabidopsis pgr5 mutant and that the other alternative routes of electrons could not compensate the stromal redox balance.
• The amplitude of the light–dark electrochromic shift (ECS) signal (ECSt), which reflects the total size of the proton motive force in steady-state photosynthesis, was reduced by 13–25% at approximately the growth light intensity.
• The CO2 fixation rate was only slightly reduced in the PGR5 KD lines. Despite the drastic reduction in NPQ and P700+ levels, total biomass was only slightly reduced in PGR5 KD lines grown at 370 mmol photons m–2s–1.

Labs working on this gene

• Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502 Japan
• CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, 102-0076 Japan
• Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Sendai, 981-8555 Japan
• National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602 Japan