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Increased expression of ANAC017 primes for accelerated senescence.

Authors :
Broda M
Khan K
O'Leary B
Pružinská A
Lee CP
Millar AH
Van Aken O
Source :
Plant physiology [Plant Physiol] 2021 Aug 03; Vol. 186 (4), pp. 2205-2221.
Publication Year :
2021

Abstract

Recent studies in Arabidopsis (Arabidopsis thaliana) have reported conflicting roles for NAC DOMAIN CONTAINING PROTEIN 17 (ANAC017), a transcription factor regulating mitochondria-to-nuclear signaling, and its closest paralog NAC DOMAIN CONTAINING PROTEIN 16 (ANAC016), in leaf senescence. By synchronizing senescence in individually darkened leaves of knockout and overexpressing mutants from these contrasting studies, we demonstrate that elevated ANAC017 expression consistently causes accelerated senescence and cell death. A time-resolved transcriptome analysis revealed that senescence-associated pathways such as autophagy are not constitutively activated in ANAC017 overexpression lines, but require a senescence-stimulus to trigger accelerated induction. ANAC017 transcript and ANAC017-target genes are constitutively upregulated in ANAC017 overexpression lines, but surprisingly show a transient "super-induction" 1 d after senescence induction. This induction of ANAC017 and its target genes is observed during the later stages of age-related and dark-induced senescence, indicating the ANAC017 pathway is also activated in natural senescence. In contrast, knockout mutants of ANAC017 showed lowered senescence-induced induction of ANAC017 target genes during the late stages of dark-induced senescence. Finally, promoter binding analyses show that the ANAC016 promoter sequence is directly bound by ANAC017, so ANAC016 likely acts downstream of ANAC017 and is directly transcriptionally controlled by ANAC017 in a feed-forward loop during late senescence.<br /> (© The Author(s) 2021. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

Details

Language :
English
ISSN :
1532-2548
Volume :
186
Issue :
4
Database :
MEDLINE
Journal :
Plant physiology
Publication Type :
Academic Journal
Accession number :
33914871
Full Text :
https://doi.org/10.1093/plphys/kiab195