Differential expression of the ribulose bisphosphate carboxylase large subunit gene in bundle sheath and mesophyll cells of developing maize leaves is influenced by light.

We have investigated the influence of light on the mRNA of the gene for the large subunit of ribulose-1,5-bisphosphate carboxylase in mesophyll and bundle sheath cells of the C(4) plant Zea mays. The gene is transcribed in both cell types in leaves of seedlings grown in the dark. However, upon illumination, the level of mRNA declines and becomes undetectable in mesophyll cells after 72 hours. On the contrary, in bundle sheath cells the two transcripts of the same gene increase to peak after 24 hours of greening and then decrease to a steady state level. This study was made possible by the development of improved methods for the isolation of two maize leaf cell types suitable for the extraction of high quality RNAs at different developmental states, i.e. etiolated, greening and green.