PLANT PHYSIOLOGY , Vol 112, Issue 2 585-590, Copyright © 1996 by American Society of Plant Biologists
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GENE REGULATION AND MOLECULAR GENETICS |
Cool Temperature-Induced Chlorosis in Rice Plants (II. Effects of Cool Temperature on the Expression of Plastid-Encoded Genes during Shoot Growth in Darkness)
R. Yoshida, A. Kanno and T. Kameya
Institute of Genetic Ecology, Tohoku University, Aoba-ku, Sendai 980-77, Japan
It has been proposed that cool temperature-induced chlorosis (CTIC) in
Indica cultivars of rice (Oryza sativa L.) is caused by cell growth and
plastid development being impeded at cool temperatures. Since it is well
known that the overall rate of transcription of plastid-encoded genes
changes dramatically during the early phases of plastid development, in
this study we focused on the patterns of expression of these genes.
Northern blot analysis revealed that the level of 16S rRNA is decreased in
a CTIC-sensitive rice cultivar grown at a cool temperature. The expression
of the gene for the [beta] subunit of plasmid RNA polymerase (rpoB) was
shown to be somewhat disturbed, particularly in terms of its resuppression
under cool conditions. The level of transcripts or proteins of
plastid-encoded photosynthetic genes was also decreased in a CTIC-sensitive
cultivar at a cool temperature. These results suggest that the
temperature-dependent inhibition of the onset of gene expression encoding
the transcription/translation apparatus may be primarily involved in the
mechanism causing CTIC.
