PLANT PHYSIOLOGY , Vol 109, Issue 1 41-52, Copyright © 1995 by American Society of Plant Biologists
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GENE REGULATION AND MOLECULAR GENETICS |
Stress Activation of a Bean Hydroxyproline-Rich Glycoprotein Promoter Is Superimposed on a Pattern of Tissue-Specific Developmental Expression
K. L. Wycoff, P. A. Powell, R. A. Gonzales, D. R. Corbin, C. Lamb and R. A. Dixon
Plant Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037 (K.L.W., P.A.P., D.R.C., C.L.)
The HRGP4.1 gene, which encodes a cell wall hydroxyproline-rich
glycoprotein, was isolated from a genomic library of bean (Phaseolus
vulgaris L.). Two transcripts, one induced by wounding and one by
elicitation, were transcribed from the same initiation site. The gene
encodes a polypeptide of 580 amino acids with the amino terminal half
consisting of repeats of the sequence
serine-(proline)4-lysine-histidine-serine-(proline)4-(tyrosine)3-histidine
and the carboxyl-terminal half composed of repeats of the sequence
serine-(proline)4-valine-tyrosine-lysine-tyrosine-lysine. A 964-bp upstream
promoter fragment was translationally fused to the [beta]-glucuronidase
reporter gene (Escherichia coli uidA) and transferred into tobacco by
Agrobacterium tumefaciens-mediated leaf disc transformation. Analysis of
[beta]-glucuronidase activity showed that wounding caused local activation
of the HRGP4.1 promoter in the phloem. Infection by tobacco mosaic virus
was a less effective inducer than wounding. Stress induction was
superimposed on tissue-specific developmental expression in stem nodes and
root tips, suggesting that HRGP4.1 may have specific structural roles in
development as well as protective functions in defense. Deletion analysis
showed that control of tissue specificity and wound inducibility lies in a
region between -94 and -251 relative to the transcription start site and
that activation by infection lies outside that region.
