Up-regulation of a cysteine protease accompanies the ethylene-insensitive senescence of daylily (Hemerocallis) flowers.
The flowers of daylily (Hemerocallis x hybrida cv. Cradle Song) open at midnight, start to senesce 12 h later, and are completely senescent by the following midnight. Differential screening of a cDNA library constructed from tepals of flowers showing incipient senescence revealed 25 clones that were strongly up-regulated in senescent tepals. Re-screening and interactive Southern analysis of these clones revealed 3 families of up-regulated clones. Transcripts of one clone, SEN10, were not detectable at midnight, but increased dramatically as senescence proceeded. The derived amino acid sequence of the full-length cDNA (SEN102) has strong homology with cysteine proteases that have been reported from other plant tissues. The sequence contains a secretory signal peptide and a probable prosequence upstream of the mature protein. Amino acids critical to the active site and structure of cysteine proteases are conserved, and the C-terminus of the polypeptide has a unique putative endoplasmic reticulum retention signal -RDEL.
Valpuesta
V
V
Departamento de Bioquímica y Biologia Molecular, Universidad de Málaga, España.
Lange
N E
NE
Guerrero
C
C
Reid
M S
MS
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary; D018744:DNA, Plant / Q000235:genetics; D005030:Ethylenes / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010940:Plant Proteins; D010944:Plants / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D015854:Up-Regulation
D018076:DNA, Complementary; D018744:DNA, Plant; D005030:Ethylenes; D010940:Plant Proteins; C036216:ethylene; D003546:Cysteine Endopeptidases; C095059:SEN102 protein, Hemerocallis