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The next green revolution

In this Ontario lab, bacteria are working to drive nutrient uptake and accelerate crop growth

“I believe we can reduce the use of chemical fertilizers and pesticides by bio-based fertilizers and pesticides.” – Dr. Ze-Chun Yuan, Agriculture and Agri-Food Canada

Scientists are delving deeper into the soil in hope of finding that next innovation to boost yields while enhancing soil health and reducing pollution concerns. And it seems they’re onto something. Or, better yet, some things.

In particular, a scientist with Agriculture and Agri-Food Canada (AAFC) has looked inside decomposing corn roots in southern Ontario and found several beneficial bacterial strains with fascinating potential uses.

It wasn’t simple. Dr. Ze-Chun Yuan isolated the bacterium Paenibacillus polymyxa in 2016, five years after joining AAFC and screening more than 20,000 bacteria from different sources.

That search included leaves, roots, soil, water and agricultural waste and residues, from which the research team distilled their screenings down to 3,000 bacterial isolates. From there, Yuan determined that P. polymyxa could be utilized as a fertilizer or a form of pesticide based on its capabilities.

Different strains of the bacterium have been isolated and shown to be capable of fixing nitrogen, producing plant hormones and even breaking down lignocellulose.

If that sounds too scientific, the potential implications are very, very easy to understand.

As much as growers are driven to continue using fertilizers to drive higher yields and pesticides to protect crop from disease, Yuan maintains both classes of products can cause environmental and ecological problems. Soil degradation, water pollution and reduced production efficacy can result from continued reliance on chemical fertilizers and pesticides.

“I believe we can reduce the use of chemical fertilizers and pesticides by bio-based fertilizers and pesticides, which will reduce the input for agriculture sectors,” says Yuan, a research scientist with AAFC-London. “They can also help the environment and ecosystems with reduced use and spraying of chemical pesticides which can be toxic to animal or human health.”

More than just fixing nitrogen, P. polymyxa can solubilise potassium and phosphorus, making them more readily available to plants while reducing the potential for the nutrients to run-off to the environment. The bacterium can also produce hormones that can enhance plant growth. In other words, it’s a double gain.

With farmers spending $4 billion per year on fertilizer, the increased efficiency in plant usage means higher yields and welcome savings for growers. Reducing the potential for pollution in nearby watercourses — and ultimately the Great Lakes — would be another advantage.

Sifting through the numbers

The road to innovation in agriculture is rarely an overnight success story, and Yuan’s discovery has come with the passage of eight years and the help of 30 undergrad students involved in the isolation work screening the bacteria, with complete genome sequencing to isolate bacterial strains in order to better understand the bacteria and their potential for applications on the farm.

“This represents the first complete bacterium genome sequencing at AAFC,” Yuan points out.

In 2019, Yuan and his team of students and technicians tested 1,200 bacterial strains in a field setting. Each bacterium inoculated 12 corn plants in a row, with roughly 60 exhibiting “significant growth promotion.” He’s hoping to repeat the field experiments again in 2020.

Outside interest

The work at AAFC-London has attracted the attention of many private sector interests as well as the Grain Farmers of Ontario. Two other bacterial strains that Yuan and his team have characterized — Bacillus velezensis 1B-23 and B. sp. 1D-12 — produce Surfactin, a bacterial cyclic lipopeptide, which protects tomatoes against bacterial canker. The Journal of Plant Pathology (see Added reading) recently accepted a report for publication detailing that discovery. And Metagenome Bio Inc., based in Waterloo, Ont., is in discussion with AAFC’s commercialization office in a bid to license P. polymyxa CR1, B. velezensis 1B-23 and a third bacterial strain, Bacillus velezensis 9D-6.

Now, the Grain Farmers of Ontario has invited Yuan to submit a full proposal to fund four years of research to determine how much fertilizer can be reduced with the bacterial strains identified thus far.

The AAFC research has advanced to the point where Yuan’s team has determined which bacteria are capable of promoting crop growth, working with corn and canola, plus tomatoes and peppers on the horticultural side. Yuan adds that they’ll be testing the bacteria in other crops, and that there’s been some work on seed coating and polymerization as delivery methods for commercial applications.

“Some bacteria in our collection may be able to act through the plant side — for example — help the plants develop better root systems (besides providing plants with more N, P and K), which we’ll investigate in the future,” says Yuan. “We know some of the bacteria we isolated produce plant hormones that regulate plant development, in particular, promote root growth. In addition to producing antimicrobials that kill disease pathogens, some bacteria may induce or awaken plant defences or enhance immunity to biotic or abiotic stresses, which are areas we hope to investigate as well.”

Those developments will come with funding support from government or private sector companies.

The other important point about Yuan’s research is that any development will be a supplement to what farmers are already using: they will not replace fertilizers or pesticides. For one, there’s the sheer size of the conventional market for those products and farmers have been using chemical fertilizers and fungicides for decades. Compare that to the early stages within the emerging field of bio-fertilizers and bio-pesticides market.

Instead, Yuan contends that bio-fertilizers, can reduce the use of conventional fertilizers by as much as 20 per cent while maintaining yields.The same situation will apply with bio-pesticides; the bacteria will complement existing products, not replace them.

At this early stage of development, the market and scale for bio-based products is quite small, a reflection of the process, not the potential. As with any new technology, it takes time to ramp up production to a level where costs aren’t prohibitive to the user and profitability to the manufacturer enables a viable market to take shape, much like the early days of personal computers.

“The storage, shipping and application of the bacterium-based products is also different from chemical products, which may need added training for a sales team or the farm equipment sector,” says Yuan.

If there’s one final inducement. though, it’s that biobased products may have the potential to enhance food quality, safety, flavour and nutrient value. That, says Yuan, would be something to entice consumers.

Says Yuan, “We believe the microbe-based products may bring in the next green revolution in the future.”

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Ralph Pearce

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