How far are we from N-Fixing Wheat, Corn & Canola?

Pasteur spring wheat. Photo Credit: Lyndsey Smith 2013

Dry atmospheric air contains about 20% oxygen and over 78% nitrogen. Nitrogen, in its molecular, gaseous form (N2(g)) is very stable, and does not react easily with other compounds. In order to be used, then, the coupled nitrogen atoms must first be split. Consider it similar to asking a new couple for help with harvest. If you leave the couple to their own devices, you will likely grow frustrated with their lack of efficiency. They are good at staying together, not so good at anything else. Once you split them up, however, they are more obedient, reactive and less…nauseating.

The process of splitting up coupled nitrogen atoms is called nitrogen-fixation, and essentially converts atmospheric nitrogen to ammonia. It occurs industrially (through the Haber Process, for example) and naturally (through lightning and in certain species of bacteria). Leguminous crops have long been known for their symbiotic relationship with Rhizobia, a nitrogen-fixing genus of bacteria, making them an important addition to crop rotations. But, imagine if all major crops had the same potential!

Well, according to the University of Nottingham, the ability for non-leguminous plants to work symbiotically with nitrogen-fixing bacteria is not just possible, it’s been studied for over ten years!

Edward Cocking, professor and director of The University of Nottingham’s Centre for Crop Nitrogen Fixation, has studied a bacteria identified in sugar-cane, and found it is entirely capable of colonizing the cells of all major crop plants. His hopes now are to see it to use in cropland worldwide, increasing food security and sustainability.

“If fully successful, it would make the crops self-fertilizing for nitrogen and this is a key requirement for sustainable agriculture now and in the years ahead,” said Cocking, in a recent media release from the University of Nottingham.

The bacteria, labeled “N-Fix” invades young root cells of sugarcane, colonizing the cytoplasm (the jelly-like substance that fills the cell) and using sucrose derived from the plant’s photosynthesis as energy for nitrogen-fixation. What’s unique about this particular bacterium? Well, in the right conditions, N-Fix bacteria does not discriminate in host or cell selection! Where Rhizobium are known to only colonize root nodules of legumes, N-Fix moves up from roots to invade other cells as well.

But, applying the technology wasn’t an easy endeavour. Right off the bat, Cocking and his team encountered trouble, as the bacterium would not enter the roots of crops besides sugarcane. They found, however, that they could stimulate the bacterium by simply giving it sucrose. And, once inside, the bacterium no longer needed additional sucrose, finding all it needs within the cells of the plant.

“We’re coating the seeds with this N-fixing bacteria,” explains Cocking. “You use the equivalent of a hairspray-sticker to get the bacteria to attach to the seed…and as the seeds germinate, the bacterium will be waiting…to interact with the emerging root of the seed.”

The implications of this technology are incredible, to say the least. According to Azotic Technologies Ltd, N-Fix replaces up to 60% of the nitrogen needs of the plant. Imagine a simple seed coating replacing much of the synthetic nitrogen applied to crops. We would be burning fewer fossil fuels (right from fertilizer production all the way to transportation and application), improving our bottom line (assuming the N-fix pricing will not be ridiculous) and decreasing the production of greenhouse gases. There would also be fewer concerns around environmental leaching of nitrogen. And neither the bacteria nor the crops would require genetic modification, if that’s something that worries you.

Azotic has already been granted licensing rights by the University of Nottingham and intends to work on field trials and commercialization of “N-Fix.” The technology is expected to be released commercially in two to three years, pending good field-trial results and regulatory application and approval.

 

Debra Murphy

Debra Murphy is a Field Editor based out of central Alberta, where she never misses a moment to capture with her camera the real beauty of agriculture. Follow her on Twitter @RealAg_Debra

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3 Comments

Shaun Haney

The process of fixing N with the corn plant is needed but it seems that when you talk to people that are willing to be honest it is further away than any of us would like to hear or accept.

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Brian Rossnagel

As usual these folks don’t provide the whole story nor do they give one any baselines for comparison. What the fail to advise is that, just like the symbiotic (emphasis on symbiotic!) relationship between pulse crop and the rhizobia which fix N for those species there is a cost to the plant to get that done. There is no free lunch.

Symbiosis means there is a sharing of benefit and COST. In the case of plants working symbiotically with various microorganisms to fix N the plant provides energy from photosynthesis to drive the fixation of the N by the microorganism. This means that energy is NOT available for the plant to produce dry matter, i.e. grain or forage, meaning that while there may be some N available to the plant there will be less yield of product from that plant. The question must be asked as to what is the acceptable trade off between N fixed by the microorganism and the overall yield (i.e $$) produced. Often times that compromise is not acceptable ion terms of economic sustainability. In addition these folks do not give any indication of just how efficient the N fixation is by this bacteria and how close that comes to being able to provide enough N to produce an economically viable crop. While I truly hope these folks have found an efficient N fixing organism for non-legume crop production based on previous attempts at this over much more than just the past 20 years I a somewhat skeptical.

Yet another one of those news items that ranks pretty high on the Rossnagel BioBS scale at 6.7 out of a possible10.

Brian Rossnagel
Prof Emeritus, Barley & Oat Breeder’
U of Sask.

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