THE PLANT CELL, Vol 1, Issue 10 961-968, Copyright © 1989 by American Society of Plant Biologists
cis-Analysis of the Wound-Inducible Promoter wun1 in Transgenic Tobacco Plants and Histochemical Localization of Its Expression
B. Siebertz, J. Logemann, L. Willmitzer and J. Schell
Max-Planck-Institut fur Zuchtungsforschung, Carl von Linne-Weg, D-5000 Koln 30, Federal Republic of Germany
The 5[prime] region of the wound-inducible gene wun1, derived from potato,
has been sequenced and analyzed for cis-acting elements important in
controlling gene expression in transgenic tobacco plants. Different
5[prime] deletion fragments were linked to the reporter gene
[beta]-glucuronidase (GUS) as transcriptional fusions, and the expression
of these chimeric genes was analyzed in leaf tissue. Sequences 111 base
pairs upstream of the transcriptional start site were not able to drive the
GUS expression over background levels, whereas sequences between -111 and
-571 showed a slightly higher activity with equal levels of transcription
in wounded and nonwounded tissue. The addition of further upstream
sequences (-571 to -1022) enhanced the level of expression by a factor
between 13 and 370. The expression driven by this fragment was inducible by
a factor of twofold to ninefold by wounding. Histochemical analysis of
different tissue from transgenic plants that contain wun1-GUS fusions
demonstrates wound-inducible and cell-specific wun1 promoter activity in
plants containing the -1022-base pair fragment. The location of GUS
activity appears to be cell-specific, being highest in epidermal cells of
leaves and stems and lower in vascular cells. Activity was reduced to
levels that could not be detected by histochemical staining in leaves,
stems, and roots of plants containing the deleted promoter fragments.
Plants that contain the different deletion constructs and plants that carry
the -1022-base pair fragment show high expression in anthers and pollen
grains that could not be stimulated by wounding.
