Autophagy deficiency leads to accumulation of ubiquitinated proteins, ER stress, and cell death in Arabidopsis

David Munch, Eleazar Rodriguez, Simon Bressendorff, Ohkmae Kim, Daniel Hofius, Morten Petersen

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Autophagy is a homeostatic degradation and recycling process that is also involved in defense against microbial pathogens and in certain forms of cellular suicide. Autophagy has been proposed to negatively regulate plant immunityassociated cell death related to the hypersensitive response (HR), as older autophagy-deficient mutants are unable to contain this type of cell death 5 to 10 d after infection. Such spreading cell death was found to require NPR1 (nonexpressor of PR genes 1), but surprisingly did not occur in younger atg mutants. In contrast, we find that npr1 mutants are not impaired in rapid programmed cell death activation upon pathogen recognition. Furthermore, our molecular evidence suggests that the NPR1-dependent spreading cell death in older atg mutants may originate from an inability to cope with excessive accumulation of ubiquitinated proteins and ER stress which derive from salicylic acid (SA )-dependent signaling (e.g., systemic acquired resistance). We also demonstrate that both senescence and immunity-related cell death seen in older atg mutants can be recapitulated in younger atg mutants primed with ER stress. We therefore propose that the reduction in SA signaling caused by npr1 loss-of-function is sufficient to alleviate the stress levels accumulated during aging in autophagy deficient cells which would otherwise become insurmountable and lead to uncontrolled cell death.

Original languageEnglish
Pages (from-to)1579-1587
Number of pages9
JournalAutophagy
Volume10
Issue number9
DOIs
Publication statusPublished - 2014 Sep 1

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology

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