Seeds as a production system for molecular pharming applications: status and prospects

The production of recombinant proteins in seeds is achieved by driving transgene expression using promoters and protein targeting sequences derived from genes encoding abundant seed storage proteins. This approach is advantageous because high yields, stability and containment are conferred by the accumulation of recombinant proteins in specialized storage compartments such as protein bodies and protein storage vacuoles. Seeds are particularly suitable for the production of pharmaceutical proteins in developing country settings because they reduce the costs of production and distribution by avoiding the need for fermenter-based production capacity and a cold chain for storage and distribution, thus increasing access to critical medicines for the poor in rural areas. Seeds are also ideal for the production of oral vaccine antigens, because encapsulation within the seed provides protection that prolongs exposure to the gastric immune system and thus increases the potency of the immune response. In this review we discuss the current state of the art in seed-based molecular pharming and the future potential of production platforms based on seeds.