Engineering bioenergy crops so they can be grown in marginal lands
Nitrogen compounds are essential to plant development, but atmospheric nitrogen must be fixed (transformed) into molecules that plants can use. Bacteria are the only organisms able to carry out nitrogen fixation.
Nitrogen-fixing bacteria are found in many environments. Some nitrogen-fixing bacteria found in the soil have the additional ability to live inside the root nodules of certain plants, such as legumes, and provide fixed nitrogen to the plant host.
Most plants utilized for bioenergy production are not capable of hosting nitrogen-fixing bacteria, so they require applications of nitrogen to increase the speed of growth. However, nitrogen application is costly, environmentally damaging, and potentially hazardous to human health.
We received funding from the U.S. Department of Energy to develop mechanisms to engineer bioenergy crops so that these plants can fix nitrogen via root nodule symbioses. If we are successful, engineered bioenergy crops could be cultivated in marginal lands that have little agricultural value due to poor soil or other characteristics.
Discovery of the genetic toolkit of nodule symbioses
Our phylogenomic approach involves obtaining genomic data form 15,000 species. We are collecting tissues of these species from different herbaria across the world.
Verification of molecular mechanisms of nodulation
We will verify the function of candidate genes discovered in Aim One for their effect on root nodule development in Medicago (nodulating) and poplar root organ cultures (non-nodulating).
Engineering nodulation in bioenergy crops
We will engineer promising genes identified in Aim Two into poplar, evaluate the development of nodules, and test the impact of these introduced genes on N-fixation and whole-plant properties.