Plant-Microbes for Improved Plant Growth and Environmental Sustainability

• Nitrogen (N) is an essential nutrient for plant growth. But since chemical fertilizers are produced using fossil fuels, excess N fertilizer in soils can be converted by soil microbes to nitrous oxide, a powerful greenhouse gas, and fertilizers in agricultural run-off can disrupt aquatic ecosystems, a more environmentally-sustainable way of improving crop growth is needed.

• Plants growing in natural, nutrient-limited conditions may rely more on symbiosis, partnerships with microbes, to obtain the nutrients they need for growth.

• My lab studies the pioneering plant species, poplar (Populus) and willow (Salix), that naturally thrive in nutrient-limited areas. Often seen in rocky riparian zones such as the one pictured at the top of this website, poplar seedlings establish on sites where few other plant species can grow.

• We have isolated and studied many different bacteria and yeast from within these wild-grown trees and studied their symbiotic properties

• These microbes improve the growth of many other plants such as grasses, corn, rice, Douglas-fir trees, bell peppers, tomatoes, and more, with reduced requirements for fertilizer and water. The ability to recruit and support beneficial microbes may have been lost in modern agricultural cultivars.

Removing Environmental Pollutants

• Standard environmental solutions such as excavation and pump-and-treat are often far too expensive to be used

• Phytoremediation is the use of plants to remove pollutants

• When pollutants are too toxic, adding natural microbes that can break down the pollutant can help phytoremediation work much better. Our successful field trial of endophyte-assisted phytoremediation of the common, carcinogenic pollutant, TCE, was published in August 2017 (see the Publications tab for that article or the News tab for a press release on the topic)

Environmentally and Economically Sustainable Bioenergy Production

• The plant biomass of choice needs to be region-specific. For the Pacific Northwest, hybrid poplar is the fastest-growing, high biomass plant for biofuel production

• With funding from the USDA/AFRI program, a strong research program for sustainable biofuels from poplar is underway: harwoodbiofuels.org

• By using natural microbial partners from wild poplar, we may be able to increase production in an environmentally-friendly way. Bioenergy or biofuels could be produced with fewer inputs since these microbes provide fixed nitrogen and bioavailable phosphate, and increase drought tolerance.

• Some of the microbes within poplar can produce valuable biochemicals and biofuels