PLANT PHYSIOLOGY , Vol 102, Issue 2 513-520, Copyright © 1993 by American Society of Plant Biologists
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MOLECULAR BIOLOGY AND GENE REGULATION |
Further Characterization of Expression of Auxin-Induced Genes in Tobacco (Nicotiana tabacum) Cell-Suspension Cultures
KJM. Boot, B. J. van der Zaal, J. Velterop, A. Quint, A. M. Mennes, PJJ. Hooykaas and K. R. Libbenga
Institute of Molecular Plant Sciences, Leiden University, Clusius Laboratory, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
We have described the modulation of four auxin-regulated genes during the
growth cycle of suspension-cultured tobacco (Nicotiana tabacum [L.] var
White Burley) cells. The genes were transiently expressed 2 to 8 h after
transfer of stationary phase cells to fresh medium, during the transition
from the quiescent phase of cells leaving the mitotic cycle to the
synthesis phase of the cell cycle. After this transient induction, the
cells showed a decreased sensitivity to auxin. Although the expression
pattern suggests that induction of these genes might be important for cell
division, over-production of antisense mRNA for one of these genes
(pCNT103) did not influence cell division in transgenic tobacco cells.
Furthermore, stimuli such as salicylic acid were capable of inducing gene
expression but were unable to restore cell division. Although these data do
not conclusively exclude a role for these genes in cell division, their
significance in this process is discussed in view of their homology with
other auxin-induced genes and in view of the specificity of hormone-induced
early responses.
