Using good bacteria to grow more crops

Chlorophyll extracted from soybean leaves – tubes right show inoculated plants - web

Chlorophyll extracted from soybean leaves – tubes on the right show inoculated plants

By Lilian Schaer for AgInnovation Ontario

Peterborough – Researchers at Trent University have discovered beneficial plant bacteria that could be used to produce more field crops like soybeans without having to farm additional land.

These bacteria, Methylobacterium , which already occur naturally in soybeans, produce plant hormones called cytokinins that promote the growth of both the plant itself and its seeds.

Now, work by Dr. Neil Emery, Professor of Biology and Vice President, Research at Trent, and fellow researcher Dr. Anna Kisiala has identified how to harness those natural hormones to encourage soybean plant health and strength and increase seed size and pod numbers.

“The basic idea is that the plant hormones I’ve worked on for decades are strongly linked to crop yield, but the problem has always been one of delivery and getting them to the right place at the right time,” explains Emery. “People have tried transgenics and sprays, but no one has made good progress in getting hormones at flower and seed where they need to be.”

Until now.

Soybeans in the greenhouse that have been inoculated with the beneficial bacteria - web

Soybeans in the greenhouse that have been inoculated with the beneficial bacteria

Although all plants have these beneficial bacteria, they don’t all necessarily produce high levels of the hormone responsible for boosting yield.

After gathering strains from various global collections and screening them for high hormone levels, Kisiala has identified and isolated some high performing strains that are now being tested on soybeans as both a seed treatment and a foliar spray.

“By replacing low performing bacteria with high producing bacteria, we hope to raise yield,” Emery adds. “The bacteria can be delivered to all parts of the plant, but we’re mostly interested in going to the seed to allow for more even pod setting and higher yields.”

The research team has already completed one year of greenhouse trials to analyze how soybeans react to the treatment, as well as a one-year field trial that evaluated different delivery methods.

Work has also started with pulses like peas and lentils to determine possible yield gains in those crops too.

Untreated soybean plant (left) next to one treated with the beneficial bacteria (right) - web

An untreated soybean plant (left) next to one that has been treated with the beneficial

“We’ve observed similar results in both years of the soybean trials, that bacteria can really increase plant growth, development and yield,” Kisiala says. “We’ve also observed that the increase depends on the delivery method so we are continuing to test this as well.”

This year, they’re moving into larger scale trials with Toronto-based industry partner NutriAg to see how well their bacteria and the different ways of applying them to crops perform in real field scenarios.

To be commercially viable, says Emery, the plant bacteria has to not just perform well but also has to be able to be applied together with an existing treatment as farmers won’t want to do an extra pass over their fields just for this application, so the research team is also testing the possibility of co-application.

With only one year of field trials behind them, Kisiala and Emery are reluctant to put numbers to any possible yield boosts, but estimate that a 10 per cent increase would not be unreasonable.

Emery and Kisiala’s work has received funding support from Grain Farmers of Ontario and Saskatchewan Pulse Growers.

Photo source: Anna Kisiala, Trent University