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

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

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

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
Volume103
Issue number2
DOIs
Publication statusPublished - 2020 Jul 1

Keywords

  • 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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