Tobacco mosaic virus and the virescence of biotechnology

There is a growing realization that a modern combination of molecular biolo gy and agriculture will provide a photosynthetic basis for the biosynthesis of an increasing variety of complex and valuable molecules. This 'greening ' of biotechnology may impact on the global environment in many beneficial ways, but will perhaps have its most significant impact on human health. In the past decade, the capacity to use plants as an expanded source of thera peutics has grown through the accelerated development of effective viral tr ansfection vectors for gene transfer to cultivated crops. Recombinant vecto rs based on tobacco mosaic virus (TMV) and other members of the Tobamovirus genus are now used to transfect commercially meaningful quantities of plan t biomass cultivated in enclosed greenhouses and multiacre fields. Viral RN A promoters are effectively manipulated for the synthesis of recombinant me ssenger RNAs in whole plants. Chimeric plant virus and virus-like particles are designed for peptide production and display from recombinant structura l protein-gene fusions. Gene functions are assessed and modified by either virus-mediated expression or cytosolic inhibition of expression at the RNA level. Recombinant virus populations, propagated by inoculating plants with infectious RNA transcripts or recombinant virions, have proved to be genet ically stable over product-manufacturing cycles. Large volumes of highly pu rified protein products isolated from transfected foliage conform reproduci bly to the specifications required for well-characterized biologics. In som e cases, they exceed the specific activities of molecules purified from alt ernative recombinant and native sources. The resulting products are then fo rmulated according to the developing national regulatory guidelines appropr iate for agriculture-based manufacturing. Each of these innovations was fir st realized by researchers using clones of tobamovirus genes and recombinan t genomes. This progress is founded on the heritage of a century of fundame ntal TMV research.