Method of producing a heterologous protein in a plastid

Method for heterologous protein production in plant cell plastids comprising introducing into a plant cell a nucleotide construct comprising a plant nuclear promoter operably linked to an intron, wherein the intron comprises a plant plastid promoter operably linked to a sequence that encodes the heterologous protein. The intron is preferably a group I or group II intron, such as the LtrB intron from Lactococcus lactis, the trnK intron from tobacco, or the atpF or petD intron from maize. Vectors, transgenic plants and transgenic plant cells are also provided.