THE PLANT CELL, Vol 2, Issue 7 591-602, Copyright © 1990 by American Society of Plant Biologists
Transient Gene Expression in Intact and Organized Rice Tissues
R. A. Dekeyser, B. Claes, RMU. De Rycke, M. E. Habets, M. C. Van Montagu and A. B. Caplan
Laboratorium voor Genetica, Rijksuniversiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium
Regulated gene expression of chimeric genes has been studied extensively in
electroporated protoplasts. The applicability of these assays is limited,
however, because protoplasts are not always physiologically identical to
the cells from which they are derived. We have developed a procedure to
electroporate DNA into intact and organized leaf structures of rice.
Optimization of the new gene delivery system mainly involved eliminating
explant-released nucleases, prolonging the DNA/explant incubation time, and
expanding the pulse time. Using a [beta]-glucuronidase gene under the
control of constitutive promoters, we demonstrated that all cell types
within a leaf base were susceptible to electroporation-mediated DNA uptake.
Although the technique was initially developed for leaf bases of young
etiolated rice seedlings, we proved that it was equally applicable both to
other monocotyledons, including wheat, maize, and barley, and to other
explants, such as etiolated and green sheath and lamina tissues from rice.
Transient gene expression assays with electroporated leaf bases showed that
the promoter from a pea light-harvesting chlorophyll a/b-binding protein
gene displayed both light- and chloroplast-dependent expression in rice,
and that the promoter from the Arabidopsis S-adenosylmethionine synthetase
gene was, as in transgenic Arabidopsis and tobacco, preferentially
expressed in cells surrounding the vascular bundles.
