Fig. 1. Plant-based production of recombinant proteins.

Expression vectors (based on binary plasmids) are transformed into Agrobacterium tumefaciens, which delivers DNA into plants for stable expression by agro-transformation (for example, using the leaf-disc method) or biolistic tools, or through transient expression by agro-infiltration. In transient expression, suspensions of bacteria (carrying the plasmids) are delivered by infiltration into leaves either manually by a syringe (small scale) or by vacuum infiltration (large scale). Following infiltration, plant expression machinery drives the expression of the genes within days. Plant tissues or cells are then harvested and extracted, followed by purification and analyses of the product.