Expression of bacterial chorismate pyruvate-lyase in tobacco: evidence for the presence of chorismate in the plant cytosol.

The bacterial gene ubiC encodes chorismate pyruvate-lyase, an enzyme which converts chorismate to 4-hydroxybenzoate and which is not normally present in plants. The UbiC protein was expressed in tobacco, with targeting of the gene product either to the plastids or to the cytosol. In both cases, chorismate pyruvate-lyase activity and a resulting formation of 4-hydroxybenzoate was detected. This suggests that chorismate, a metabolite of the shikimate pathway, is present not only in the plastids but also in the cytosol of plant cells.