DAY-LENGTH-DEPENDENT DELAYED-GREENING1, the Arabidopsis Homolog of the Cyanobacterial H+-Extrusion Protein, Is Essential for Chloroplast pH Regulation and Optimization of Non-Photochemical Quenching

Kyohei Harada, Takatoshi Arizono, Ryoichi Sato, Mai Duy Luu Trinh, Akira Hashimoto, Masaru Kono, Masaru Tsujii, Nobuyuki Uozumi, Shinichi Takaichi, Shinji Masuda

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Plants convert solar energy into chemical energy through photosynthesis, which supports almost all life activities on earth. Because the intensity and quality of sunlight can change dramatically throughout the day, various regulatory mechanisms help plants adjust their photosynthetic output accordingly, including the regulation of light energy accumulation to prevent the generation of damaging reactive oxygen species. Non-photochemical quenching (NPQ) is a regulatory mechanism that dissipates excess light energy, but how it is regulated is not fully elucidated. In this study, we report a new NPQ-regulatory protein named Day-Length-dependent Delayed-Greening1 (DLDG1). The Arabidopsis DLDG1 associates with the chloroplast envelope membrane, and the dldg1 mutant had a large NPQ value compared with wild type. The mutant also had a pale-green phenotype in developing leaves but only under continuous light; this phenotype was not observed when dldg1 was cultured in the dark for ≥8 h/d. DLDG1 is a homolog of the plasma membrane-localizing cyanobacterial proton-extrusion-protein A that is required for light-induced H+ extrusion and also shows similarity in its amino-acid sequence to that of Ycf10 encoded in the plastid genome. Arabidopsis DLDG1 enhances the growth-retardation phenotype of the Escherichia coli K+/H+ antiporter mutant, and the everted membrane vesicles of the E. coli expressing DLDG1 show the K+/H+ antiport activity. Our findings suggest that DLDG1 functionally interacts with Ycf10 to control H+ homeostasis in chloroplasts, which is important for the light-acclimation response, by optimizing the extent of NPQ.

Original languageEnglish
Pages (from-to)2660-2671
Number of pages12
JournalPlant and Cell Physiology
Volume60
Issue number12
DOIs
Publication statusPublished - 2019 Dec 1

Keywords

  • Arabidopsis
  • Chloroplast
  • H homeostasis
  • Non-photochemical quenching
  • Photosynthesis regulation

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

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