title: Removal of DELLA repression promotes leaf senescence in Arabidopsis.
abstract: Leaf senescence is an integrated response of leaf cells to developmental age and various internal and environmental signals. However, the role of gibberellins (GA) in leaf senescence is not clear. In the current study, we investigated the effect of DELLA on leaf senescence. Compared with the wild type (WT), leaf senescence occurred earlier in the mutant ga1-3 gai-t6 rga-t2 rgl1-1 rgl2-1 (abbreviated as Q-DELLA/ga1-3) whose DELLA repression was removed, whereas leaf senescence was retarded in the mutant ga1-3 whose GA biosynthesis was blocked and whose DELLA proteins accumulated abnormally. During leaf senescence, SAG12 and SAG29 were upregulated in Q-DELLA/ga1-3 and downregulated in ga1-3 plants. The Q-DELLA/ga1-3 senescent leaves contained more sugar but less chlorophyll and fatty acids (FAs) than those of ga1-3 and WT. Both absolute and relative contents of C18:3 in Q-DELLA/ga1-3 senescent leaves were lower compared with those of the WT and ga1-3 leaves. The genes regulating FA β-oxidation in Q-DELLA/ga1-3, such as KAT2, LACS6, LACS7, ACX1, ACX2 and MAP2, were significantly upregulated. The removal of DELLA repression highly upregulated certain genes on various hormone pathways, suggesting that GA signaling acts upstream of the jasmonic acid, salicylic acid, and ethylene pathways in regulating leaf senescence.
authors.affiliation: College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China.
authors.forename: Mingxun
authors.initials: M
authors.lastname: Chen
authors.affiliation: College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China.
authors.forename: Antony
authors.initials: A
authors.lastname: Maodzeka
authors.affiliation: College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China.
authors.forename: Longhua
authors.initials: L
authors.lastname: Zhou
authors.affiliation: College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China.
authors.forename: Essa
authors.initials: E
authors.lastname: Ali
authors.affiliation: College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, PR China. Electronic address: jianglx@zju.edu.cn.
authors.forename: Lixi
authors.initials: L
authors.lastname: Jiang
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000502:physiology*; D003546:Cysteine Endopeptidases / Q000378:metabolism; D005875:Gibberellins / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism; D018515:Plant Leaves / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D003546:Cysteine Endopeptidases; D005875:Gibberellins; D008565:Membrane Proteins; C109555:GAI protein, Arabidopsis; C557299:At5g13170 protein, Arabidopsis; C007842:gibberellic acid; C402082:SAG12 protein, Arabidopsis
keywords: DELLA proteins; GA signaling; Leaf senescence; β-Oxidation