Feeding of the Nine Billion – The Future of Photosynthesis and Increased Crop Productivity

A photograph showing a young Asian boy eating a corn cob. Artwork: NaturphilosophieImproving on Nature’s Photosynthesis

Agronomic engineers have managed to improve upon one the most important biological process on the planet – photosynthesis.  The increased yield in crop could be as much as 15%. 

Analysts say this is a crucial step towards increasing sustainable food production to supply our ever-growing global population.

The breakthrough, published in the journal Science, used genetic modification to boost the amount of sunlight energy that plants can channel into food production.

140-Steps to Photosynthesis

 

The basic chemical equation for photosynthesis: CO2 + H2O gives C6H12O6 + O2. The picture is describing the photosynthesis equation: Start with CO2 (carbon dioxide) + H2O (water), combine the Sun's energy to the plant's chlorophyll, and you get C6H12O6 (sugars) + O2 (oxygen).
A plant transforms the Sun’s energy into food and oxygen through the process of photosynthesis.

After decades of research into the 140-step process by which plants convert sunlight into energy, scientists have revealed specific “inefficiencies in crops” – bottlenecks holding up the conversion of sunlight energy into food.  The new research was aimed at tackling one of those bottlenecks.

 

A diagram showing photoinhibition in plant: Sunlight damages photosynthetic machinery, primarily photosystem II (PSII), and causes photoinhibition that can limit plant photosynthetic activity, growth and productivity. The extent of photoinhibition is associated with a balance between the rate of photodamage and its repair. Recent studies have shown that light absorption by the manganese cluster in the oxygen-evolving complex of PSII causes primary photodamage, whereas excess light absorbed by light-harvesting complexes acts to cause inhibition of the PSII repair process chiefly through the generation of reactive oxygen species. As we review here, PSII photodamage and the inhibition of repair are therefore alleviated by photoprotection mechanisms associated with avoiding light absorption by the manganese cluster and successfully consuming or dissipating the light energy absorbed by photosynthetic pigments, respectively.
Photoprotection in Plants Source: Cell.com

Photo-inhibition: A Plant’s Natural Sun Protection

The scientists targeted plant life’s natural Sun-protection mechanism, using tobacco (Nicotinia) plants.

While plants have advanced throughout their evolution to sustain themselves and grow using Sun light energy, they have also evolved a safeguard mechanism to shield themselves from Sun damage, which in turn slows the growth process down.

The leaf induces a process that dissipates excess energy as heat.  The extent of this photo-inhibition mechanism – a light-induced reduction in the photosynthetic capacity of a plant – is associated with a balance between the rate of photo-damage and its repair.

When a cloud passes in front of the Sun, however, the plant receives less sunlight.

 

A gif animation showing the Sun being obscured by clouds.
Scientists have bio-engineered crops able to respond faster to a decrease in sunlight. Source: giphy.com

Plant Photo-Adaption

Theoretically, the plant could use up all of the energy it receives when the amount of sunshine decreases, but it keeps on releasing that energy as heat.

The photosynthetic systems simply do not adapt to fluctuating light conditions rapidly enough, thus reducing photosynthesis efficiency.  Herein lies the challenge.

What lead researcher Professor Sophie Long and her team from the University of Illinois and University of Lancaster have done is to accelerate the process through which heat loss switches on-and-off.

They sought to bio-engineer an accelerated response of the plant to naturally-occurring shading events.

For this, the scientists inserted extra copies of the genes that mediate this heat-loss switch.  The results showed an increased leaf carbon dioxide uptake and plant dry matter productivity.

And when they grew their genetically modified tobacco crop, they found it grew 15% larger than normal.  A major improvement.

 

An illustration showing the various types of cereal crops: wheat, rye, barley, corn, rice, oats and millet.The Future of Photosynthesis and Crop Productivity

Globally, rice, wheat, maize and soybean are the biggest crops.  The researchers are now aiming to make this change in rice, soy and wheat.

A 15% yield increase in those crops would be a huge improvement.  It would greatly alleviate the future pressure on the overall food supply.

According to the Food and Agriculture Organisation of the United Nations (UNFAO), that pressure will likely intensify in the coming years.  By 2050, it is projected that the World’s nations will need to increase food production by 70%, as the global population soars to over 9 billion people.

Because the photo-protective mechanism that has been altered is common to all flowering plants and crops, the findings provide proof of concept for a route to obtaining a sustainable increase in productivity for food crops and a much-needed yield increase.

 

Artwork symbolizing population growth on Earth.
The World is becoming increasingly populated, and we must prepare for the future…

Ensuring the World’s Food Security

Considering the current rate of population growth on Earth, we are quickly going to reach a threshold to our ability to feed the World’s populations.  Today, many households are already spending almost 100% of their household income on food.

As things stand, many people do not get enough to eat.

But in the future?

Food production will need to increase by 70%.

 

In the Western world, food prices will continue to rise.  And for a few of the poorest nations, the impact of population growth will be catastrophic.

The World needs urgent sustainable innovations to secure the global food supply.

Of course, this is merely one change, and we do not yet know if these plants will require more of other resources, like water.  But it is critically important to increase harvest yields significantly, and in a sustainable way.

In terms of making Africa green and resolving the difficulties associated with farming in those parts of the World, improving those processes involved in photosynthesis is an important step in maintaining food security.  Poor farmers would be able to cultivate staple crops that could grow well across a range of different environments.  Whether during a drought or a flood, you could still have crops that remain viable even in the harshest of climatic conditions.

The breakthrough is vital.

With these new research developments, we could potentially achieve a World with zero hunger over the next 20 years.