Viral amplification of recombinant messenger RNA in transgenic plants

A method of expressing a foreign antisense RNA in a plant cell, the method comprising:

• providing a chromosomally integrated transgene in a plant cell, wherein the transgene comprises a replicon having a plus sense, RNA viral replication origin and at least one foreign gene for the antisense RNA, which gene is capable of expression in a plant or plant cell, wherein said replicon is transcribed from a promoter, and wherein said replicon is dependent for replication on a helper virus;
• providing the helper virus, wherein the helper virus comprises a plus sense RNA viral replicase;
• transcribing the transgene to form recombinant mRNA comprising the replicon;
• replicating the recombinant mRNAs with the plus sense RNA viral replicase, thereby producing additional replicon components;
• and,
• producing subgenomic mRNA from the additional replicon components, thereby expressing the antisense RNA in the plant cell.

A method of expressing a foreign ribozyme in a plant cell, the method comprising:

• providing a chromosomally integrated transgene in a plant cell, wherein the transgene comprises a replicon having a plus sense, RNA viral replication origin and at least one foreign gene for the ribozyme RNA, which gene is capable of expression in a plant or plant cell, wherein said replicon is transcribed from a promoter, and wherein said replicon is dependent for replication on a helper virus;
• providing the helper virus, wherein the helper virus comprises a plus sense RNA viral replicase;
• transcribing the transgene to form recombinant mRNA comprising the replicon;
• replicating the recombinant mRNAs with the plus sense RNA viral replicase, thereby producing additional replicon components;
• and,
• producing subgenomic mRNA from the additional replicon components, thereby expressing the ribozyme RNA in the plant cell.

A method of expressing a foreign protein in a plant cell, the method comprising:

• providing a chromosomally integrated transgene in a plant cell, wherein the transgene comprises a replicon having a plus sense, RNA viral replication origin and at least one foreign gene for the foreign protein, which gene is capable of expression in a plant or plant cell, wherein said replicon is transcribed from a promoter, and wherein said replicon is dependent for replication on a helper virus;
• providing the helper virus, wherein the helper virus comprises a plus sense RNA viral replicase;
• transcribing the transgene to form recombinant mRNA comprising the replicon;
• replicating the recombinant mRNAs with the plus sense RNA viral replicase, thereby producing additional replicon components;
• producing subgenomic mRNA from the additional replicon components, thereby expressing the foreign protein gene in the plant cell;
• and,
• translating the subgenomic mRNA of the expressed foreign protein gene, thereby producing the foreign protein.