Autophagy contributes to nighttime energy availability for growth in Arabidopsis

Masanori Izumi, Jun Hidema, Amane Makino, Hiroyuki Ishida

研究成果: Article査読

92 被引用数 (Scopus)

抄録

Autophagy is an intracellular process leading to the vacuolar degradation of cytoplasmic components. Autophagic degradation of chloroplasts is particularly activated in leaves under conditions of low sugar availability. Here, we investigated the importance of autophagy in the energy availability and growth of Arabidopsis (Arabidopsis thaliana). autophagy-deficient (atg) mutants showed reduced growth under short-day conditions. This growth inhibition was largely relieved under continuous light or under short-day conditions combined with feeding of exogenous sucrose, suggesting that autophagy is involved in energy production at night for growth. Arabidopsis accumulates starch during the day and degrades it for respiration at night. Nighttime energy availability is perturbed in starchless mutants, in which a lack of starch accumulation causes a transient sugar deficit at night. We generated starchless and atg double mutants and grew them under different photoperiods. The double mutants showed more severe phenotypes than did atg or starchless single mutants: reduced growth and early cell death in leaves were observed when plants were grown under 10-h photoperiods. Transcript analysis of dark-inducible genes revealed that the sugar starvation symptoms observed in starchless mutants became more severe in starchless atg double mutants. The contents of free amino acids (AAs) increased, and transcript levels of several genes involved in AA catabolism were elevated in starchless mutant leaves. The increases in branched-chain AA and aromatic AA contents were partially compromised in starchless atg double mutants. We conclude that autophagy can contribute to energy availability at night by providing a supply of alternative energy sources such as AAs.

本文言語English
ページ(範囲)1682-1693
ページ数12
ジャーナルPlant physiology
161
4
DOI
出版ステータスPublished - 2013 4

ASJC Scopus subject areas

  • 生理学
  • 遺伝学
  • 植物科学

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