Autophagy Contributes to the Quality Control of Leaf Mitochondria

Sakuya Nakamura, Shinya Hagihara, Kohei Otomo, Hiroyuki Ishida, Jun Hidema, Tomomi Nemoto, Masanori Izumi

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

In autophagy, cytoplasmic components of eukaryotic cells are transported to lysosomes or the vacuole for degradation. Autophagy is involved in plant tolerance to the photooxidative stress caused by ultraviolet B (UVB) radiation, but its roles in plant adaptation to UVB damage have not been fully elucidated. Here, we characterized organellar behavior in UVB-damaged Arabidopsis (Arabidopsis thaliana) leaves and observed the occurrence of autophagic elimination of dysfunctional mitochondria, a process termed mitophagy. Notably, Arabidopsis plants blocked in autophagy displayed increased leaf chlorosis after a 1-h UVB exposure compared to wild-type plants. We visualized autophagosomes by labeling with a fluorescent protein-tagged autophagosome marker, AUTOPHAGY8 (ATG8), and found that a 1-h UVB treatment led to increased formation of autophagosomes and the active transport of mitochondria into the central vacuole. In atg mutant plants, the mitochondrial population increased in UVB-damaged leaves due to the cytoplasmic accumulation of fragmented, depolarized mitochondria. Furthermore, we observed that autophagy was involved in the removal of depolarized mitochondria when mitochondrial function was disrupted by mutation of the FRIENDLY gene, which is required for proper mitochondrial distribution. Therefore, autophagy of mitochondria functions in response to mitochondrion-specific dysfunction as well as UVB damage. Together, these results indicate that autophagy is centrally involved in mitochondrial quality control in Arabidopsis leaves.

Original languageEnglish
Pages (from-to)229-247
Number of pages19
JournalPlant & cell physiology
Volume62
Issue number2
DOIs
Publication statusPublished - 2021 May 11

Keywords

  • Arabidopsis (Arabidopsis thaliana)
  • Autophagy
  • Mitochondria
  • Mitophagy
  • Organelle quality control
  • Ultraviolet B

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

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