Universal Expression Tools to Improve Nutrient Acquisition of Energy Crops

Plant growth and development relies on roots as a means to anchor the plant body as well as to absorb water and nutrients such as N, P and K. The current development of growing crops on marginal land (low water content, low nutrient supply, vulnerability to erosion and heavy-metal pollution) for bioenergy will reduce competition with food crops and the pressure on high-quality arable lands utilization. In order to compensate for the lack of nutrients in the soil, root systems in energy crops can be engineered through synthetic biology to generate complex metabolic pathways to improve nutrient acquisition/accumulation in plants.

The introduction of complex metabolic pathways into plants opens new opportunities to utilize plant-based platforms for production of molecules of interest. However the tools for such characterization and modifications specifically in plants are lacking. Designing “universal” expression tools for plant root engineering functional across diverse plant species would dramatically advance our ability to modify crops beyond traditional methods. Our aim is to generate “universal” promoter libraries which can ultimately be used for tissue specific metabolic pathway engineering in bioenergy crops. In house transcriptome analysis of various bioenergy crops will identify root specific genes that are constitutively expressed, induced or repressed through conserved metabolic responses to N, P and Fe starvation in hydroponic conditions across a widely diverse selection of plant species. Promoters from the identified genes are isolated and characterized for spatiotemporal expression patterns and expression levels across different taxonomic classes using composite plants and transgenic approaches. An efficient method for DNA assembly into a suite of plant transformation vectors leveraging in vivo yeast homologous recombination has been developed to this aim. Thus the identified promoters along with a number of genes could be used for complex metabolic pathways in bioenergy crops in a tissue specific manner.