Blue light control of the level of two plastid mRNAs in cultured plant cells.

In suspension cultured callus cells of tobacco (Nicotiana tabacum var. 'Samsun') the development of chloroplasts is strictly blue light-dependent. During this process chlorophylls and other pigments as well as membrane and stroma proteins are synthesized de-novo. Cloned chloroplast genes of mustard encoding the large subunit (LSU) of ribulosebisphosphate carboxylase/oxygenase (EC. 4.1.1.39; RuBPCase) and the precursor polypeptide of the 32-kD membrane protein were used to study the effect of blue light on the steady-state concentration of the complementary mRNA sequences. For both a rapid increase in dark-grown cells in response to blue light-irradiation was detected by RNA dot-hybridization technique. The time courses coincide with those previously elucidated for the synthesis rates of both LSU and the membrane protein. The results support the notion that blue light acts primarily through mRNA induction.