INVESTIGATORS: Jan Leach, Daniel Bush, Andrew Kern, Hei Leung, John McKay, Bingyu Zhao
INSTITUTION: Colorado State University, Dartmouth College, International Rice Research Institute, Virginia Tech University
NON-TECHNICAL SUMMARY: Developing a successful and sustainable biofuels program requires unprecedented inputs of biomass for energy conversion. The US has focused on perennial grasses, including switchgrass, for development as “new energy” biomass crops because of their water and nitrogen use efficiency, and their high cellulosic biomass relative to traditional crops. However, if the ‘new energy’ crops are to meet future energy demands, their agronomic and biomass productivity traits must be significantly improved. Unfortunately, the genetic tools necessary to enhance the agronomic and feedstock attributes of these grasses are currently limited. To expedite the identification of genes that control biomass productivity, we established a gene discovery pipeline using rice, a model grass with tremendous genetic tools. The goal of this research is to leverage knowledge from rice to expedite discovery of biomass genes in switchgrass, a mode of analysis referred to as translational genomics. In addition to fundamental discoveries about biomass genes, this work will greatly expand the research tool box for switchgrass and will expedite improvement of switchgrass as an energy crop.
OBJECTIVES: We will: (1) identify and validate novel genes in rice that enhance biomass accumulation, (2) discover biomass genes in switchgrass, (3) validate the roles of biomass genes in transgenic switchgrass, and (4) create a web-based display to facilitate the comparison and translation of information from rice to switchgrass.
APPROACHES: Our prior work demonstrated that plants can achieve high biomass production by using independent developmental and physiological pathways. These pathways are likely controlled by different genes, suggesting that there are multiple gene targets for biomass improvement. To identify these gene targets, we are using a systems approach that measures variation in gene sequence through to the impacts of that variation on biomass accumulation. This approach is driven by a comprehensive phenotyping pipeline that includes assessment of transcript variation, photosynthesis, cell wall composition, growth rate, and final biomass in both rice and switchgrass mutants/transgenics. A web-based resource will be developed to facilitate comparison and integration of rice and switchgrass data. Genes and genomic regions that control high biomass accumulation and optimal cell wall composition will be identified from naturally-occurring diverse rice varieties or induced rice mutants. Select gene candidates will be validated for their role in biomass by gene silencing and/or complementation of function in rice. Those genes which show biomass function in rice will be advanced to transgenic switchgrass studies (down-regulation or overexpression) to confirm their function in switchgrass. A switchgrass coding sequence-based linkage map will be developed to facilitate discovery of new genes and genomic regions that control biomass in switchgrass.
Name: Leach, J.