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Phosphorus toxicity disrupts Rubisco activation and reactive oxygen species defence systems by phytic acid accumulation in leaves
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  • Daisuke Takagi,
  • Atsuko Miyagi,
  • Youshi Tazoe,
  • Mao Suganami,
  • Maki Kawai-Yamada,
  • Akihiro Ueda,
  • Yuji Suzuki,
  • Ko Noguchi,
  • Naoki Hirotsu,
  • Amane Makino
Daisuke Takagi
Tohoku University
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Atsuko Miyagi
Saitama Daigaku
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Youshi Tazoe
Tohoku University
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Mao Suganami
Tohoku University
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Maki Kawai-Yamada
Saitama University
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Akihiro Ueda
Hiroshima University
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Yuji Suzuki
Iwate University
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Ko Noguchi
Tokyo Yakka Daigaku Seimei Kagakubu Daigakuin Seimei Kagaku Kenkyuka
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Naoki Hirotsu
Toyo University
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Amane Makino
Tohoku University
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Abstract

Phosphorus (P) is an essential mineral nutrient for plants. Nevertheless, excessive P accumulation in leaf mesophyll cells causes necrotic symptoms in land plants; this phenomenon is termed P toxicity. However, the detailed mechanisms underlying P toxicity in plants have not yet been elucidated. This study aimed to investigate the molecular mechanism of P toxicity in rice. We found that under excessive inorganic P (Pi) application, Rubisco activation decreased and photosynthesis was inhibited, leading to lipid peroxidation. Although the defence systems against reactive oxygen species (ROS) accumulation were activated under excessive Pi application conditions, the Cu/Zn-type superoxide dismutase activities were inhibited. A metabolic analysis revealed that excessive Pi application led to an increase in the cytosolic sugar phosphate concentration and the activation of phytic acid synthesis. These conditions induced mRNA expression of genes that are activated under metal-deficient conditions, although metals did accumulate. These results suggest that P toxicity is triggered by the attenuation of both photosynthesis and metal availability within cells mediated by phytic acid accumulation. Here, we discuss the whole phenomenon of P toxicity, beginning from the accumulation of Pi within cells to death in land plants.

Peer review status:ACCEPTED

17 Mar 2020Submitted to Plant, Cell & Environment
17 Mar 2020Submission Checks Completed
17 Mar 2020Assigned to Editor
25 Mar 2020Reviewer(s) Assigned
30 Mar 2020Review(s) Completed, Editorial Evaluation Pending
05 Apr 2020Editorial Decision: Revise Minor
08 Apr 20201st Revision Received
08 Apr 2020Submission Checks Completed
08 Apr 2020Assigned to Editor
09 Apr 2020Review(s) Completed, Editorial Evaluation Pending
09 Apr 2020Editorial Decision: Accept