title: Large-scale identification of leaf senescence-associated genes.
abstract: Leaf senescence is a form of programmed cell death, and is believed to involve preferential expression of a specific set of "senescence-associated genes" (SAGs). To decipher the molecular mechanisms and the predicted complex network of regulatory pathways involved in the senescence program, we have carried out a large-scale gene identification study in a reference plant, Arabidopsis thaliana. Using suppression subtractive hybridization, we isolated approximately 800 cDNA clones representing SAGs expressed in senescing leaves. Differential expression was confirmed by Northern blot analysis for 130 non-redundant genes. Over 70 of the identified genes have not previously been shown to participate in the senescence process. SAG-encoded proteins are likely to participate in macromolecule degradation, detoxification of oxidative metabolites, induction of defense mechanisms, and signaling and regulatory events. Temporal expression profiles of selected genes displayed several distinct patterns, from expression at a very early stage, to the terminal phase of the senescence syndrome. Expression of some of the novel SAGs, in response to age, leaf detachment, darkness, and ethylene and cytokinin treatment was compared. The large repertoire of SAGs identified here provides global insights about regulatory, biochemical and cellular events occurring during leaf senescence.
authors: Faculty of Biology, Technion, Israel Institute of Technology, Haifa 32000, Israel. gepstein@tx.technion.ac.il
authors: Shimon
authors: S
authors: Gepstein
authors: Gazalah
authors: G
authors: Sabehi
authors: Marie-Jeanne
authors: MJ
authors: Carp
authors: Taleb
authors: T
authors: Hajouj
authors: Mizied Falah Orna
authors: MF
authors: Nesher
authors: Inbal
authors: I
authors: Yariv
authors: Chen
authors: C
authors: Dor
authors: Michal
authors: M
authors: Bassani
mesh_terms: D000375:Aging / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics; D003001:Cloning, Molecular; D004798:Enzymes / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018515:Plant Leaves / Q000235:genetics* / Q000254:growth & development*
chemical_list: D029681:Arabidopsis Proteins; D004798:Enzymes