ARABIDOPSIS-THALIANA CARBONIC-ANHYDRASE - CDNA SEQUENCE AND EFFECT OF CO2 ON MESSENGER-RNA LEVELS

A full-length cDNA clone encoding carbonic anhydrase was isolated from an Arabidopsis thaliana (Columbia) leaf library. Comparison of the derived amino acid sequence obtained from this clone with those of pea and spinach reveals a considerable degree of identity. The carbonic anhydrase cDNA was used to probe the level of RNA encoding this protein in the leaves of plants grown in elevated CO2 (660 ppm). We have found that under these conditions the steady-state level of carbonic anhydrase mRNA was increased in comparison with control plants grown in normal atmospheric concentrations of CO2 (330 ppm). This raises the intruiging possibility that there exists in higher plants a mechanism for perceiving and responding to changes in environmental CO2 concentrations at the genetic level.