University of Guelph research rooted in traditional seeds and driven by contemporary science is helping plants produce their own all-important nitrogen. The findings could lead to a more sustainable way to provide crops with the nitrogen boost they need.
A plant must have nitrogen to grow, but it can’t produce the essential element on its own, said lead researcher Prof. Manish Raizada in the Department of Plant Agriculture. Nitrogen fertilizer is the preferred way to feed it to plants, but there may be an alternative.
The research is focused on specific microbes in plants that are capable of converting nitrogen in the atmosphere into plant food. Infusing seeds with optimal nitrogen-producing microbes has the potential to significantly reduce or even replace the traditional method of manufacturing nitrogen fertilizer, which is a major contributor of greenhouse gases.
Raizada said the production of nitrogen fertilizer may be possible through a more environmentally sustainable microbial bioreactor process, whereby air is fed to microbes and nitrogen plant food is produced. He envisions a time when seeds coated with probiotic microbes and microbial sprays for soil could become commercial products.
“When you breathe, 80 per cent of the gas you are actually breathing in is nitrogen,” Raizada said. “That nitrogen gas is in a form that plants and humans can’t use. It’s microbes that have to convert it into a usable form.”
Raizada’s team at U of G is feeding plants these beneficial microbes to help them manufacture nitrogen. They have identified the best microbes for the job, those found in ancient South American varieties of corn seeds.
The researchers discovered that some varieties of so-called land race corn – developed through selective breeding over thousands of years – thrive without the application of additional nitrogen.
The research goes back a few years, when Raizada and graduate student David Johnston Monje worked together to identify the microbes associated with plants that grew exceptionally well without a nitrogen boost.
“It turns out that there are some Indigenous peoples throughout Mexico and Central America, where corn originates, that report that they are able to grow corn without much nitrogen,” Raizada said. “We started a collaboration with the large CIMMYT, The International Maize and Wheat Improvement Center in Mexico, which holds the seed bank for the world’s corn seeds. David examined dozens of these corn seeds.”
Johnston Monje discovered intriguing types of bacteria on seeds that were able to grow well without added nitrogen. He concluded that one microbe in particular was especially adept at producing nitrogen from the air and infusing it into plants. His tests found that the presence of the microbe consistently boosted the size of rye grass – a relative of corn – by 50 to 100 per cent. Other microbes also showed promise.
“We knew we had a lot of good candidates and we knew that we had this really great candidate,” Raizada said, adding that the research was recently supported by a $29,000 grant from U of G’s Research Innovation Office. That funding helped secure another $125,000 from the Natural Sciences and Engineering Research Council to support greenhouse trials in wheat and grasses. Cornfield trials in Canada and Columbia are planned.
Agricultural crops, Raizada said, are treated with nitrogen fertilizers that are manufactured through a process that burns huge amounts of fossil fuel. About half of nitrogen fertilizer used on corn is wasted, either leaching into groundwater or turning into greenhouse gases.
One important question the researchers are interested in exploring is whether these microbes can make fertilizer on their own, without the need for a plant.
“The question we’re now asking is, why can’t we just put microbes in a bioreactor, feed them air and get them to make fertilizer? That is a long-term goal for us,” Raizada said. “It’s a huge ongoing experiment.”
Source : University of Guelph