Abstract
Microalgae are considered to play a key role in aquatic carbon fixation. Most of unicellular algae possess inorganic carbon concentrating mechanism which confers cells to do high-affinity photosynthesis for dissolved inorganic carbon. The expression of intracellular β carbonic anhydrase in the marine diatom Phaeodactylum tricornutum has been shown to be response to changes in pCO2 in the culture media. In the present, the function of the promoter region of β-CA gene was analysed in P. tricornutum. The chimeric gene in which 5'-upstream region of CA gene was fused to a GUS reporter gene was constructed and introduced into the cell by microparticle bombardment. The results demonstrated that the GUS activity exhibited in air-grown transformants was 15-25 fold that in 5% CO2-grown cells. The critical cis-elements in β-CA promoter which are required for CO2 responsibility of β-CA are being investigated by loss- and gain- of function assay of this promoter region.
