Diel magnesium fluctuations in chloroplasts contribute to photosynthesis in rice

Jian Li, Kengo Yokosho, Sheng Liu, Hong Rui Cao, Naoki Yamaji, Xin Guang Zhu, Hong Liao, Jian Feng Ma, Zhi Chang Chen

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Photosynthesis provides food, fibre and fuel that support our society; understanding the mechanisms controlling dynamic changes in this process helps identify new options to improve photosynthesis. Photosynthesis shows diel changes, which have been largely attributed to external light/dark conditions, as well as internal gene expression and the post-translational modification of critical enzymes. Here we report diel fluctuations of magnesium (Mg) in rice (Oryza sativa) chloroplasts, which may function as a rhythm regulator contributing to the post-translational regulation of photosynthetic CO2 assimilation in rice. We found that a chloroplast-localized Mg2+ transporter gene, OsMGT3, which is rhythmically expressed in leaf mesophyll cells, partly modulates Mg fluctuations in rice chloroplasts. Knockout of OsMGT3 substantially reduced Mg2+ uptake, as well as the amplitude of free Mg2+ fluctuations in chloroplasts, which was closely associated with a decrease in ribulose 1,5-bisphosphate carboxylase activity in vivo and a consequent decline in the photosynthetic rate. In addition, the mesophyll-specific overexpression of OsMGT3 remarkably improved photosynthetic efficiency and growth performance in rice. Taken together, these observations demonstrate that OsMGT3-dependent diel Mg fluctuations in chloroplasts may contribute to Mg-dependent enzyme activities for photosynthesis over the daily cycle. Enhancing Mg2+ input to chloroplasts could be a potential approach to improving photosynthetic efficiency in plants.

Original languageEnglish
Pages (from-to)848-859
Number of pages12
JournalNature Plants
Volume6
Issue number7
DOIs
Publication statusPublished - Jul 1 2020

ASJC Scopus subject areas

  • Plant Science

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