PLANT PHYSIOLOGY , Vol 103, Issue 3 933-941, Copyright © 1993 by American Society of Plant Biologists
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MOLECULAR BIOLOGY AND GENE REGULATION |
Effects of Light Fluence and Wavelength on Expression of the Gene Encoding Cucumber Hydroxypyruvate Reductase
G. P. Bertoni and W. M. Becker
Department of Botany, University of Wisconsin, Madison, Wisconsin 53706
We have investigated the regulation of cucumber (Cucumis sativus)
hydroxypyruvate reductase mRNA abundance in response to white-, red-, and
far-red-light treatments. Following irradiation of dark-adapted cucumber
seedlings with 15 min to 4 h of either white or red light and return to
darkness, the mRNA level for the gene encoding hydroxypyruvate reductase
(Hpr) in cotyledons peaks in the darkness 16 to 20 h later. The response of
the Hpr mRNA level to total fluence of white light depends more directly on
irradiation time than on fluence rate. In addition to this time-dependent
component, a phytochrome-dependent component is involved in Hpr regulation
in dark-adapted green cotyledons as shown by red-light induction and
partial far-red-light reversibility. Parallel measurements of mRNA levels
for the ribulose bisphosphate carboxylase/oxygenase small subunit and for
the chlorophyll a/b-binding protein show that Hpr is the most responsive to
short (about 60 min) white- and red-light treatments and that each mRNA has
a characteristic pattern of accumulation in dark-adapted cotyledons in
response to light.
