Cytokinin Induces a Rapid Decrease in the Levels of mRNAs for Catalase, 3-Hydroxy-3-methylglutaryl CoA reductase, Lectin and Other Unidentified Proteins in Etiolated Cotyledons of Cucumber

摘要

Large-scale differential hybridization was performed to examine rapid changes in gene expression caused by a phytohormone, cytokinin, in etiolated cotyledons of cucumber (Cucumis sativusL.). We isolated 86 cDNA clones for mRNAs whose levels decreased within 2 h of the start of treatment with N6-benzyladenine (BA). Partial nucleotide sequences showed that some of the cDNAs were homologous to those for catalase, 3-hydroxy-3-methylglutaryl CoA reductase (HMGR) and a lectin. This is the first report that the levels of the mRNAs for those proteins are regulated by a cytokinin in darkness. Together with previous results Teramoto et al. (1993)Physiol. Plant. 87: 584, (1994)Planta193: 573, (1995)Planta196: 387, the present study suggests that the cytokinin act to lower the levels of mRNAs transcribed from various genes in etiolated cotyledons.