Transcription factor RD26 is a key regulator of metabolic reprogramming during dark-induced senescence.
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) RD26 as an important regulator of metabolic reprogramming in Arabidopsis thaliana. RD26 directly activates CHLOROPLAST VESICULATION (CV), encoding a protein crucial for chloroplast protein degradation, concomitant with an enhanced protein loss in RD26 overexpressors during senescence, but a reduced decline of protein in rd26 knockout mutants. RD26 also directly activates LKR/SDH involved in lysine catabolism, and PES1 important for phytol degradation. Metabolic profiling revealed reduced γ-aminobutyric acid (GABA) in RD26 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. RD26 also supports the degradation of starch and the accumulation of mono- and disaccharides during senescence by directly enhancing the expression of AMY1, SFP1 and SWEET15 involved in carbohydrate metabolism and transport. Collectively, during senescence RD26 acts by controlling the expression of genes across the entire spectrum of the cellular degradation hierarchy.
['Kamranfar|Iman|I|', 'Xue|Gang-Ping|GP|', 'Tohge|Takayuki|T|', 'Sedaghatmehr|Mastoureh|M|', 'Fernie|Alisdair R|AR|', 'Balazadeh|Salma|S|', 'Mueller-Roeber|Bernd|B|']
D000596:Amino Acids D017360:Arabidopsis D029681:Arabidopsis Proteins D001665:Binding Sites D060365:Chloroplast Proteins D002952:Citric Acid Cycle D003624:Darkness D018506:Gene Expression Regulation, Plant D017343:Genes, Plant D055442:Metabolome D008954:Models, Biological D010836:Phytol D030821:Plants, Genetically Modified D059748:Proteolysis D036226:Seedlings D000073893:Sugars D014157:Transcription Factors D005680:gamma-Aminobutyric Acid
senescence Arabidopsis respiration fatty acid primary metabolism protein and amino acid degradation