Amritapuri, Vallikavu, Kerala 690525
Karen A. McDonald, Ph.D.
Associate Dean for Research & Graduate Studies, University of California at Davis
Advances in the Development of Plant Molecular Foundries
Plants are a vast renewable source of important natural products, and the development of genetic engineering approaches has opened up a myriad of new possibilities for extending the biosynthetic capabilities of plants by enabling the production of heterologous proteins and new metabolic pathways in whole plants, plant tissues and in-vitro systems such as plant cell cultures in bioreactors. Although plant biotechnology has been deployed commercially for decades for improved agronomic traits of crops, the combination of new expression technologies and synthetic biology building blocks for plants, rapid and inexpensive DNA synthesis, and novel bioprocessing strategies are enabling plants and/or plant cells to be used as molecular foundries to solve some of our most important societal problems in health and energy in an environmentally-friendly way. For example, new production platforms based on transient expression in nontransgenic plants within contained manufacturing facilities are showing enormous promise for rapid, scalable production of recombinant proteins, without the need to deploy transgenic plants and eliminating many of the environmental concerns. A soil bacterium, Agrobacterium tumefaciens, that has an inherent capability of interkingdom DNA transfer, is used to introduce the genetic instructions into plant cells. Plant cells within the plant tissues then provide the biosynthetic machinery for transcription, translation, post-translational modifications, folding and intracellular targeting/secretion of the product. Thus the approach combines the advantages of rapid, easy and inexpensive growth of bacteria in fermentation systems with the biosynthetic capabilities of higher eukaryotic cells which have been grown using minimal energy and resource inputs (using sunlight and natural resources). Transgenic plant cell cultures grown in bioreactors provide an alternative approach that is also attractive, particularly for production of human and veterinary therapeutics Biotechnology and bioprocessing engineering approaches for enhancing recombinant protein production using transient agroinfiltration and transgenic plant cell cultures will be presented with applications to human therapeutics, vaccines, and industrial enzymes.