PLANT PHYSIOLOGY , Vol 108, Issue 4 1413-1421, Copyright © 1995 by American Society of Plant Biologists
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GENE REGULATION AND MOLECULAR GENETICS |
Impaired Wound Induction of 3-Deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) Synthase and Altered Stem Development in Transgenic Potato Plants Expressing a DAHP Synthase Antisense Construct
J. D. Jones, J. M. Henstrand, A. K. Handa, K. M. Herrmann and S. C. Weller
Departments of Horticulture (J.D.J., J.M.H., A.K.H., S.C.W.) and Biochemistry (K.M.H.), Purdue University, West Lafayette, Indiana 47907-1165
Potato (Solanum tuberosum L.) cells were transformed with an antisense DNA
construct encoding part of 3-deoxy-D-arabino-heptulosonate-7-phosphate
(DAHP) synthase (EC 4.1.2.15), the first enzyme of the shikimate pathway,
to examine the role(s) of this protein in plant growth and development.
Chimeric DNA constructs contained the transcript start site, the first
exon, and part of the first intron of the shkA gene in antisense or sense
orientations under the control of the cauliflower mosaic virus 35S
promoter. Some, but not all, of the transgenic plants expressing antisense
DAHP synthase RNA showed reduced levels of wound-induced DAHP synthase
enzyme activity, polypeptide, and mRNA 12 and 24 h after wounding. No
alteration in the wound induction of DAHP synthase gene expression was
observed in transgenic potato tubers containing the chimeric sense
construct. Reduced steady-state levels of DAHP synthase mRNA were observed
in stem and shoot tip tissue. Some plants with the chimeric antisense
construct had reduced stem length, stem diameter, and reduced stem
lignification.