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Transcription factor RD 26 is a key regulator of metabolic reprogramming during dark‐induced senescence
Author(s) -
Kamranfar Iman,
Xue GangPing,
Tohge Takayuki,
Sedaghatmehr Mastoureh,
Fernie Alisdair R.,
Balazadeh Salma,
MuellerRoeber Bernd
Publication year - 2018
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15127
Subject(s) - senescence , phytol , microbiology and biotechnology , biology , biochemistry , transcription factor , catabolism , anabolism , transcriptome , reprogramming , metabolism , chemistry , gene expression , gene
Summary Leaf senescence is a key process in plants that culminates in the degradation of cellular constituents and massive reprogramming of metabolism for the recovery of nutrients from aged leaves for their reuse in newly developing sinks. We used molecular–biological and metabolomics approaches to identify NAC transcription factor ( TF ) RD 26 as an important regulator of metabolic reprogramming in Arabidopsis thaliana . RD 26 directly activates CHLOROPLAST VESICULATION ( CV ), encoding a protein crucial for chloroplast protein degradation, concomitant with an enhanced protein loss in RD 26 overexpressors during senescence, but a reduced decline of protein in rd26 knockout mutants. RD 26 also directly activates LKR / SDH involved in lysine catabolism, and PES 1 important for phytol degradation. Metabolic profiling revealed reduced γ‐aminobutyric acid ( GABA ) in RD 26 overexpressors, accompanied by the induction of respective catabolic genes. Degradation of lysine, phytol and GABA is instrumental for maintaining mitochondrial respiration in carbon‐limiting conditions during senescence. RD 26 also supports the degradation of starch and the accumulation of mono‐ and disaccharides during senescence by directly enhancing the expression of AMY 1 , SFP 1 and SWEET 15 involved in carbohydrate metabolism and transport. Collectively, during senescence RD 26 acts by controlling the expression of genes across the entire spectrum of the cellular degradation hierarchy.