Optimising agricultural efficiency and output is key to being able to feed a quickly growing world population on the same or diminishing natural resources such as land and soil. The environmental impact of intense, commercial-scale agriculture is also well-publicised.
The large volumes of usually nitrogen-based fertiliser required to achieve the agricultural output we need is one of the largest contributors to the environment impact that unfortunately results. Biotech researchers think they may be on to part of the answer. It is centred on a strain of corn that self-fertilises through unique ‘roots’ above ground that absorb nitrogen from the air which it then converts into fertiliser.
The corn hails from the Sierra Mixe region, a mountainous area of southern Mexico where the soil has poor concentrations of nitrogen. Soils that are considered ‘rich’ and best suited to agriculture have high nitrogen levels. Because cereals like corn, wheat, oats, rice and barley lack the same bacteria in their roots that legumes like beans and peas have, which convert atmospheric nitrogen into ammonias that aid growth, farmers have to add far more fertiliser to these crops. The production of man-made fertilisers has a high carbon footprint as it’s an energy-intense process. It also finds its ways into waterways where high concentrations can lead to dense concentrations of algae, called ‘blooms’ and even dead zones when the natural nutrient balance is heavily disrupted.
The Sierra Mixe corn is unique in that it has aerial roots that resemble small red cucumbers covered in a mucus. That mucus is teeming with bacteria that very efficiently converts nitrogen the roots suck out of the air into fertiliser for the plants growth. This means the corn grows much bigger than other strains, up to 16 feet, without the need for any fertiliser to be added.
The reason that the remarkable strain has not yet been adopted by mainstream agriculture is that despite its natural efficiencies it takes 8 months to mature. The strains grown for commercial agriculture need only 3 months. However, biotech researchers from the University of California (UC), Davis, believe that if the Sierra Mixe’s self-fertilising aerial roots can be bred into commercial corn strains, which they think is possible, it could be an agriculture game changer. It would massively reduce the amount of fertiliser large scale commercial corn production currently requires, slashing farming costs while simultaneously solving the environmental repercussions.
The team are also approaching their research ethically by involving the local Sierra Mixe population, whose unique indigenous corn strain it is hoped will offer the genetic material for a future biotech breakthrough. Legal agreements have been signed with Mexico’s government, ensuring that any commercial benefits that result will be shared with the local community. This is in line with the international Nagoya Protocol framework introduced to prevent ‘bio piracy’. It’s the first time such an agreement between a U.S. biotech entity and a local community has ever been ratified.
The UC Davis team lead, Alan Bennett, has been aware of the Sierra Mixe corn for over a decade and was convinced that the strange tubular growths on the corn were self-fertilising the plant. However, the biotechnology of the time was unable to prove it. Now, modern DNA-sequencing techniques and chemical analysis have allowed Bennett to prove that the mucus dripping from the roots contains bacteria from nitrogen-fixing families. The mucus also contains the sugar and offers the protection from oxygen essential to the process of converting airborne nitrogen into fertilising ammonias.
For years, biotech scientists have been working on trying to create genetically modified nitrogen-fixing cereals. So far they have had very little success. It still has to be demonstrated if the Sierra Mixe corn’s upper roots can fix enough nitrogen for large scale commercial plantations and the strain’s genes may come with other, as yet unknown, drawbacks. However, while at an early stage, if the research shows potentially huge promise especially if the relevant genes could eventually be spliced into other cereals. If it comes off, the amount of fertiliser used in commercial farming could potentially be massively reduced.