In the future, plants will be able to create their own fertilizer. Farmers will no longer need to buy and spread fertilizer for their crops, and increased food production will benefit billions of people around the world, who might otherwise go hungry.
These statements may sound like something out of a science fiction novel, but new research by Washington University in St. Louis scientists show that it might soon be possible to engineer plants to develop their own fertilizer. This discovery could have a revolutionary effect on agriculture and the health of the planet.
The research, led by Himadri Pakrasi, the Glassberg-Greensfelder Distinguished University Professor in the Department of Biology in Arts & Sciences and director of the International Center for Energy, Environment and Sustainability (InCEES); and Maitrayee Bhattacharyya-Pakrasi, senior research associate in biology, was published in the May/June issue of mBio.
Creating fertilizer is energy intensive, and the process produces greenhouse gases that are a major driver of climate change. And it’s inefficient. Fertilizing is a delivery system for nitrogen, which plants use to create chlorophyll for photosynthesis, but less than 40 percent of the nitrogen in commercial fertilizer makes it to the plant.
After a plant has been fertilized, there is another problem: runoff. Fertilizer washed away by rain winds up in streams, rivers, bays and lakes, feeding algae that can grow out of control, blocking sunlight and killing plant and animal life below.
However, there is another abundant source of nitrogen all around us. The Earth’s atmosphere is about 78 percent nitrogen, and the Pakrasi lab in the Department of Biology just engineered a bacterium that can make use of that atmospheric gas — a process known as “fixing” nitrogen — in a significant step toward engineering plants that can do the same.
The research was rooted in the fact that, although there are no plants that can fix nitrogen from the air, there is a subset of cyanobacteria (bacteria that photosynthesize like plants) that is able to do so. Cyanobacteria can do this even though oxygen, a byproduct of photosynthesis, interferes with the process of nitrogen fixation.