Cloning and characterization of a receptor-like protein kinase gene associated with senescence.
Senescence-associated genes are up-regulated during plant senescence and many have been implicated in encoding enzymes involved in the metabolism of senescing tissues. Using the differential display technique, we identified a SAG in bean (Phaseolus vulgaris) leaf that was exclusively expressed during senescence and was designated senescence-associated receptor-like kinase (SARK). The deduced SARK polypeptide consists of a signal peptide, a leucine-rich repeat in the extracellular region, a single membrane-spanning domain, and the characteristic serine/threonine protein kinase domain. The mRNA level for SARK increased prior to the loss of chlorophyll and the decrease of chlorophyll a/b-binding protein mRNA. Detached mature bean leaves, which senesce at an accelerated rate compared with leaves on intact plants, showed a similar temporal pattern of SARK message accumulation. Light and cytokinin, which delayed the initiation of leaf senescence, also delayed SARK gene expression; in contrast, darkness and ethylene, which accelerated senescence, advanced the initial appearance of the SARK transcript. SARK protein accumulation exhibited a temporal pattern similar to that of its mRNA. A possible role for SARK in the regulation of leaf senescence was considered.
Hajouj
T
T
Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Michelis
R
R
Gepstein
S
S
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D016922:Cellular Senescence; D003001:Cloning, Molecular; D007887:Fabaceae / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D010946:Plants, Medicinal; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013997:Time Factors
D010940:Plant Proteins; D011956:Receptors, Cell Surface; C423445:senescence-associated receptor-like kinase, Phaseolus vulgaris; D017346:Protein Serine-Threonine Kinases