Phytochrome control of gene expression in radish seedlings. III. Evidence for a rapid control of the ribulose 1,5 bisphosphate carboxylase small subunit gene expression by red light

Abstract

The effect of red and far-red light on the level of the mRNA encoding the small subunit (SSU) of ribulose 1,5 bisphosphate carboxylase (RuBisCO; EC 4.1.1.39) from radish cotyledons was investigated. Northern blot analysis of RNA with a cDNA probe showed that both long (12–36 h) far-red irradiation and short (1–5 min) red irradiation brings about an increase in SSU mRNA concentration which was prevented by a subsequent far-red light exposure. Far-red light was effective in reversing the red light effect provided that it was given soon after (<10 min) the red light pulse. The red light mediated increase in SSU mRNA level did not occur in presence of α-amanitin. Our results suggest that phytochrome control of SSU gene expression is exerted at the transcriptional level.