An Agricultural Revolution: More Efficient Photosynthesis

By Ananya Vinay

Fresno, California

Amanda De Souza, one of the RIPE project research scientists, with RIPE's crops. (Allie Arp / Carl R. Woese Institute for Genomic Biology / University of Illinois)

In the push for organic food, we have all been warned away from GMOs, or genetically modified organisms. But the truth is that, in modern times, everything is bioengineered. Scientific innovation has expanded the limits of alteration, from physical characteristics to the core of photosynthesis. As a matter of fact, for the first time ever, it has been proven that multi-gene bioengineering of photosynthesis can improve crop yields. This research took place at the University of Illinois as a part of the Realizing Increased Photosynthetic Efficiency (RIPE) project, an international project aiming to increase global food production.

This feat manipulated the VPZ construct, three genes that controlled the production of xanthophyll, which is a hormone protecting plants from excessive heat. While plants are in full sunlight, xanthophyll activates processes that dissipate excess energy. Of course, this process is not needed during the shade. The issue comes in when transitioning between shade and sunlight. It takes several minutes for photoprotection to switch off. Consequently, valuable time and organic sugars are lost in the time that photosynthesis does not take place. We all think of photosynthesis as the process that sustains life, but we don’t realize that it’s highly inefficient, with over 100 steps and two distinct cellular mechanisms, with and without light. Researchers at RIPE have been working for over a decade to improve the efficiency of photosynthesis.

By over-expressing the genes related to photoprotection, scientists were able to speed up the process of switching off photoprotection. In essence, as more leaves transitioned, photosynthesis sped up as a part of the positive feedback cycle. A few minutes without photosynthesis doesn’t seem like a big deal, but when added up, the overall photosynthetic rate is greatly impacted. It’s remarkable that over-expressing one gene cluster increased the yield by greater than 20% with no impact on seed quality. This could be explained by the extra energy being diverted to nitrogen fixation, ensuring that the amount of protein in seeds was equal.

This protocol was first tested in tobacco plants, as tobacco plant genes are easier to transform and produce more seeds. Food crops are more difficult because they require a year or more for planting and harvesting. However, the fact that bioengineered photosynthesis succeeded in two vastly different crops suggests that this innovation is widely applicable, though more testing is needed to ensure its efficacy across different climates and environments. For these scientists’ decades worth of work, it is commendable that they identified one key gene modification that increases yield simply by adding minutes to the process of photosynthesis.

Beyond the scientific achievement, the implications of this innovation are staggering. Nearly 10% of the world’s population faces food insecurity, according to the UN. By 2030, more than 660 million people are predicted to face food scarcity. Most agree that the cause is clear: inefficient food supply chains and harsher environmental conditions. Climate change has a large impact on agriculture. It worsens droughts, increases flooding, and contributes to high temperatures, none of which is good for climate change. Put simply, bioengineering photosynthesis could save lives. Yes, one successful field test is only scratching the surface. But we cannot deny that this development holds promise.

Regardless, there are still limitations. Bioengineering on a large scale is costly, and promoting this technology in developing nations would require a great deal of investment and infrastructure development. A couple extra minutes of photosynthesis can make a difference. In impoverished areas, this discovery can change lives for smallholder farmers. With appropriate investment and development, the project has the potential to pave the way for a revolution in agriculture.