Diel magnesium fluctuations in chloroplasts contribute to photosynthesis in rice

Autor: Hong Liao, Sheng Liu, Xin-Guang Zhu, Kengo Yokosho, Naoki Yamaji, Hong Rui Cao, Jian Li, Jian Feng Ma, Zhi Chang Chen
Rok vydání: 2020
Předmět:
Zdroj: Nature Plants. 6:848-859
ISSN: 2055-0278
Popis: 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.
Databáze: OpenAIRE
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