Overproduction of PGR5 enhances the electron sink downstream of photosystem I in a C4 plant, Flaveria bidentis

Yushi Tazoe, Noriko Ishikawa, Toshiharu Shikanai, Keiki Ishiyama, Daisuke Takagi, Amane Makino, Fumihiko Sato, Tsuyoshi Endo

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)


    C4 plants can fix CO2 efficiently using CO2-concentrating mechanisms (CCMs), but they require additional ATP. To supply the additional ATP, C4 plants operate at higher rates of cyclic electron transport around photosystem I (PSI), in which electrons are transferred from ferredoxin to plastoquinone. Recently, it has been reported that the NAD(P)H dehydrogenase-like complex (NDH) accumulated in the thylakoid membrane in leaves of C4 plants, making it a candidate for the additional synthesis of ATP used in the CCM. In addition, C4 plants have higher levels of PROTON GRADIENT REGULATION 5 (PGR5) expression, but it has been unknown how PGR5 functions in C4 photosynthesis. In this study, PGR5 was overexpressed in a C4 dicot, Flaveria bidentis. In PGR5-overproducing (OP) lines, PGR5 levels were 2.3- to 3.0-fold greater compared with wild-type plants. PGR5-like PHOTOSYNTHETIC PHENOTYPE 1 (PGRL1), which cooperates with PGR5, increased with PGR5. A spectroscopic analysis indicated that in the PGR5-OP lines, the acceptor side limitation of PSI was reduced in response to a rapid increase in photon flux density. Although it did not affect CO2 assimilation, the overproduction of PGR5 contributed to an enhanced electron sink downstream of PSI.

    Original languageEnglish
    Pages (from-to)814-823
    Number of pages10
    JournalPlant Journal
    Issue number2
    Publication statusPublished - 2020 Jul 1


    • C photosynthesis
    • Flaveria bidentis
    • PGR5
    • cyclic electron transport
    • electrochromic shift
    • fluctuating light
    • proton motive force

    ASJC Scopus subject areas

    • Genetics
    • Plant Science
    • Cell Biology


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