Open AccessBinding of Spermidine to a Unique Protein in Thin-Layer Tobacco Tissue Culture
Author(s) -
Akiva Apelbaum,
Zoe N. Canellakis,
Philip B. Applewhite,
Ravindar KaurSawhney,
Arthur W. Galston
Publication year - 1988
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.88.4.996
Subject(s) - spermidine , putrescine , spermine , trichloroacetic acid , biochemistry , dormancy , polyamine , biology , tissue culture , nicotiana tabacum , chemistry , botany , enzyme , in vitro , germination , gene
The mechanism by which spermidine induces the appearances of floral buds in thin-layer tobacco (Nicotiana tabacum) tissue culture was studied by following the fate of the radioactive compound. [3H]Spermidine was taken up rapidly by the tissue, and after a brief lag, a portion was bound to trichloroacetic acid precipitable macromolecules. Such binding increased to a maximum on day 4 of culture, coinciding with the onset of bud differentiation, and declined thereafter until shortly before flowering. About 82% of the label in the trichloroacetic acid precipitate remained as spermidine, 14% was metabolized to putrescine, 3% to spermine, and 1% to gamma-aminobutyric acid. Spermidine was covalently bound to a protein with a molecular size of about 18 kilodaltons. Hydrolysis of this protein and analysis of the labeled entities revealed 81% spermidine, 16% putrescine, and 3% spermine. This post-translational modification of a unique protein by attachment of spermidine may be causally connected to the appearance of flower buds in thin-layer tobacco cultures.