More than 20 post-transcriptional gene silencing (PTGS) suppressors have been found since HC-Pro, the first gene silencing suppressor, was found in 1998. The silencing suppressor strongly suggested that gene silencing functions as natural defense mechanisms against viruses. It also represented a valuable tool for the dissection of the gene silencing pathway. We have used P1/HC-Pro RNA silencing suppressor activity to increase green fluorescent protein (GFP) expression in tobacco using an Agrobacterium-mediated transient expression system. P1/HC-Pro stimulated GFP-gene expression but not dsGFP-gene expression was shown by RT-PCR, Northern and Western blot analysis. Expression of the gene silencing suppressor and the target gene provided a new strategy of heterogeneous gene expressing in plants. It may be of commercial significance to produce foreign proteins using plant bioreactors.