WEST LAFAYETTE, INDIANA, US — Plant science research at Purdue University has found a potential way to double soybean plants’ use of nitrogen, called biological nitrogen fixation.
“We are working to enhance the plant’s efficiency at utilizing atmospheric nitrogen, so that we can reduce the need for fertilizer,” said Jianxin Ma, a professor of agronomy in the Purdue University College of Agriculture, who led the study. “This is better for the farmer and better for the environment.”
When fields become depleted of nitrogen, heavy doses of expensive and environmentally damaging fertilizer must be added to maintain yields, said Ma, who was recently honored by the Crop Science Society of America.
Soybeans provide 25% of the world’s edible oil and 66% of the protein in livestock feed. A beneficial change in the plant could impact approximately 300 million acres of farmland worldwide, Ma said.
“This is an example of how science can be used to improve plants and our environment,” he said. “Genetic research provides important knowledge for plant breeding, which has been used to create new plant cultivars for centuries. Now we are able to do this faster, more precisely, and with a more complete understanding of how it will affect the plant and the environment.”
Ma is part of Purdue’s Next Moves in plant sciences and a member of Purdue’s Center for Plant Biology. His research initiative on biological nitrogen fixation originally was funded by a College of Agriculture AgSEED grant, and now includes support from the USDA, United Soybean Board and Indiana Soybean Alliance.
Using CRISPR gene-editing technology and other molecular techniques, Ma showed that soybeans have genes that suppress the formation of root nodules, where the nitrogen-fixing soil bacteria called rhizobia convert the atmospheric nitrogen into forms the plant can use. He also showed that some tiny RNA molecules produced by the beneficial bacteria can turn off the soybean genes slowing nodule formation.
By precisely identifying the bacterial RNAs and mechanism involved in blocking the “detrimental” soybean gene, he discovered a path to increasing a plant’s efficiency at root nodule formation. The research is detailed in a paper published in the journal Science.