title: Regulation and execution of molecular disassembly and catabolism during senescence.
abstract: Senescence is a highly orchestrated developmental stage in the life cycle of plants. The onset of senescence is tightly controlled by signaling cascades that initiate changes in gene expression and the synthesis of new proteins. This complement of new proteins includes hydrolytic enzymes capable of executing catabolism of macromolecules, which in turn sets in motion disassembly of membrane molecular matrices, leading to loss of cell function and, ultimately, complete breakdown of cellular ultrastructure. A distinguishing feature of senescence that sets it apart from other types of programmed cell death is the recovery of carbon and nitrogen from the dying tissue and their translocation to growing parts of the plant such as developing seeds. For this to be accomplished, the initiation of senescence and its execution have to be meticulously regulated. For example, the initiation of membrane disassembly has to be intricately linked with the recruitment of nutrients because their ensuing translocation out of the senescing tissue requires functional membranes. Molecular mechanisms underlying this linkage and its integration with the catabolism of macromolecules in senescing tissues are addressed.
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1.
authors.forename: Marianne
authors.initials: M
authors.lastname: Hopkins
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1.
authors.forename: Catherine
authors.initials: C
authors.lastname: Taylor
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1.
authors.forename: Zhongda
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1.
authors.forename: Fengshan
authors.initials: F
authors.lastname: Ma
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1.
authors.forename: Linda
authors.initials: L
authors.lastname: McNamara
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1.
authors.forename: Tzann-Wei
authors.initials: TW
authors.lastname: Wang
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1.
authors.forename: John E
authors.initials: JE
authors.lastname: Thompson
mesh_terms: D018506:Gene Expression Regulation, Plant; D063245:Plant Development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D010944:Plants / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D010940:Plant Proteins