Transgenic perennial biofuel feedstocks and strategies for bioconfinement

Abstract

The use of transgenic tools for the improvement of plant feedstocks will be required to realize the full economic and environmental benefits of cellulosic and other biofuels, particularly from perennial plants. Traits that are targets for improvement of biofuels crops include herbicide resistance, pest, drought, cold and salt tolerance, nutrient use efficiency, altered cell wall composition and improved processing and end-use characteristics. However, controlling gene flow is a major issue and there is no regulatory experience with perennial plants as dedicated biofuels feedstocks. Bioconfinement of transgenes is thus an obvious regulatory and biosafety objective to the release and commercialization of transgenic bioenergy feedstocks. In this article, we review bioconfinement strategies that target pollen or seeds that can be applied to perennial plants used as biofuels. These include male sterility, integration of transgenes into plastid genomes, removal of transgenes in pollen and seeds, transgene expression in vegetative organs for harvest before appearance of reproductive structures or gene use restriction technologies.

Dedication

This paper is dedicated to the memory of Peter Mascia (1950–2009) who contributed significantly to this manuscript prior to his passing on 28 May 2009.

Acknowledgements

The authors recognize and appreciate the work of our respective research groups.

Financial & competing interests disclosure

The authors appreciate funding from the Bioenergy Science Center, a DOE bioenergy center to CNS, USDA Biotechnology Risk Assessment grants to most of the authors and the US Environmental Protection Agency Office of Research & Development for funding to Lidia S Watrud. We also appreciate funding from the DOE Biomass Program (award # DE-FG-36_08GO88070) to Albert P Kausch. Mention of trade names or commercial products does not imply recommendation for use; the article has been subjected to USEPA administrative and peer review and has been approved for publication. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.