Science

Scientists hack plant photosynthesis to boost crop yields by 40%

The genetically modified crops grow faster and taller than their conventional counterparts 
The genetically modified crops grow faster and taller than their conventional counterparts 
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The genetically modified crops grow faster and taller than their conventional counterparts 
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The genetically modified crops grow faster and taller than their conventional counterparts 
The modified crops versus the unmodified crops
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The modified crops versus the unmodified crops
The modified crops versus the unmodified crops
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The modified crops versus the unmodified crops

An international team of researchers has, for the first time, demonstrated that by fixing a common glitch in photosynthesis, a crop's yield could be improved by around 40 percent. The landmark study suggests optimizing a plant's photosynthetic efficiency could significantly increase worldwide food productivity.

Photosynthesis, the process by which a plant converts light energy into chemical energy, is not a wholly efficient process. A key stage in the photosynthesis process involves an enzyme called RuBisCO grabbing carbon dioxide molecules. However, around 25 percent of the time RuBisCO incorrectly collects oxygen molecules instead, creating a plant-toxic byproduct that disrupts the entire photosynthesis process. Photorespiration is the process plants use to remove these problematic byproducts.

"Photorespiration is anti-photosynthesis," explains Paul South, lead author on the new research. "It costs the plant precious energy and resources that it could have invested in photosynthesis to produce more growth and yield."

In food crops such as soybean, rice and wheat, it's estimated that photorespiration can take up anywhere from 20 to 50 percent of a plant's photosynthetic energy. So it is no surprise that scientists have been working hard to find ways to lower the energy cost of photorespiration.

Realizing Increased Photosynthetic Efficiency (RIPE) is an international research project founded in 2012 with the primary goal of developing ways to increase food crop yields by engineering more efficient photosynthesis techniques. The project is primarily funded by the Bill and Melinda Gates Foundation, and earlier this year it revealed an exciting simple genetic breakthrough that resulted in crops needing 25 percent less water to produce a regular yield.

To battle the energy cost of photorespiration, a team of scientists worked to engineer more efficient and significantly shorter photorespiratory pathways. The incredible work essentially created alternate routes within a plant cell so the toxic byproducts could be more efficiently removed using less energy.

"Much like the Panama Canal was a feat of engineering that increased the efficiency of trade, these photorespiratory shortcuts are a feat of plant engineering that prove a unique means to greatly increase the efficiency of photosynthesis," says RIPE Director Stephen Long.

The modified crops versus the unmodified crops
The modified crops versus the unmodified crops

The new process was subsequently tested using tobacco crops, a common target for crop research due to its fast lifecycle and ease of modification. Over two years of real-world testing, the engineered crops were found to grow taller, faster and develop up to 40 percent more biomass than their regular counterparts.

The modified crops versus the unmodified crops
The modified crops versus the unmodified crops

The next stage of the research will apply this technique to more common food crops such as soybean, rice, potato, and tomato with the hopes it will boost those crop's yields. The researchers suspect it will be well over a decade before this breakthrough can be applied in real-world conditions.

There is bound to be a regulatory battle to establish safety profiles before such a genetically modified food crop is widely grown. Nevertheless, one of RIPE's fundamental commitments is that these food engineering innovations will be freely available to smallholder famers so these technological breakthroughs can help feed growing populations in third-world nations.

"We could feed up to 200 million additional people with the calories lost to photorespiration in the Midwestern U.S. each year," suggests principal investigator Donald Ort, on the benefits the breakthrough could have in the United States. "Reclaiming even a portion of these calories across the world would go a long way to meeting the 21st Century's rapidly expanding food demands—driven by population growth and more affluent high-calorie diets."

The new research was published in the journal Science.

Source: University of Illinois

16 comments
Nik
This may be preferable to modifying plants to be more tolerant to poisons sprayed on them, but why not just fix the problem of the RuBisCO error process itself, rather than cleaning up afterwards?
grtblu
Given the environmental need to get rid of CO2 in our atmosphere, this process applied to forests could help with greenhouse gas reductions. I wonder what photorespiriation percentage various types of trees exhibit. Interesting work.
Aross
Instead of all this screwing around with nature and causing who knows what kind of future health problems, we are what we eat, lets find ways to slow or even reverse the out of control population growth.
Nik
grtblu.....If I was an alien looking for a planet to colonise, had found Earth, and wished to remove all existing plant and animal life, so I could start afresh with life forms from my own environment, then removing all the CO2 would be the simplest and most effective way to achieve that! All land life on the Earth is carbon based, the source of most of that carbon, is the CO2 in the atmosphere............got it??
Doodah
Nik, it’s about balance. Everyone knows of course that CO2 is important, no one would argue that (we should be thankful that our problem isn’t global cooling-which would be far more devastating than warming). It’s about the balance of it. Too much isn’t necessarily good. It’s like Sugar, which has always been a fundamental way we’ve been able to tell whether or not a food wasn’t poison. Therefore we derive energy from it and can tolerate a large amount of it. Eliminating all sugars would be a huge mistake. But the issues with too much of it are quite clear and obvious. How accurate the science is is perhaps another debate, but I think that stating simply that Carbon dioxide is important therefore the debate is over isn’t productive.
Robert in Vancouver
This process would help feed millions of starving people, so let's do it. But it won't get rid of any CO2. CO2 trapped in plants gets released after plants die or are eaten. The same thing goes for trees. Current levels of CO2 are barely high enough to feed the trees and plants we currently have. If modified plants absorb 30% to 50% more CO2 we will need to create new CO2 to keep the world green. Commercial greenhouses already pump extra CO2 into their buildings to feed their crops because there isn't enough natural CO2.
Kpar
"Biological glitches" are often in place for a reason, and not necessarily obvious. We may be able to improve plant efficiency, but there is always the law of unintended consequences. Move slowly and carefully on this...
Douglas E Knapp
Those of you living in the south (USA) know what kuduz is, right? It is only a little bit more efficient than native plants. Can you imagine what would happen when a plant got loose in the wild that was 40% better than all the other plants?
Nik
Doodah....The present level of CO2, is the LOWEST it has been for 270 million years, since the Permian extinction. So is global average temperature during this interglacial period. In addition, the Earth has been in an ice age for around the last 30-40 million years, and it will get colder, because the Earth is presently in an inter glacial warm period, which will end in the not too distant future. The signs of its approaching end are already present. Then it will get even colder. That cooling will reduce the dissolved CO2 released from the oceans, the same as cold beer retains its CO2. The present level of CO2 at about 400 ppm is already dangerously low for life on Earth. If atmospheric CO2 falls below 150 ppm, then all land plant life will begin to die, closely followed by all animal life dependent upon it. The reason the climate is warming, is that a huge proportion of the Earths surface is now desert. Take a look at the Earth on google satellite. A large proportion of this desert is man made, by deforestation, and no regeneration. Massive deforestation started at the same time as the industrial age, hence the fact that the present very slight warming coincided with that. CO2 does not cause warming and never has. Deforestation does. The low level of CO2, and low level of surface nutrients in the soil, means that even existing forests are starving, are weak, and more vulnerable to disease, and forest fires. The cause of the ice age, the solar systems entry into one of the arms of the Milky Way galaxy, will also cause more earthquakes and volcanic activity. This will reduce sunlight, and cause more cooling. All this is on million year timescales, but not the end of the interglacial warm period. Deep sea cores have shown that the change can be very abrupt, and in the past, has occurred in as little as 20-50 years. The interglacial period lasts 10-15 thousand years, on average. This one has already lasted that long. When it really begins to become apparent, all the major food growing areas wont, and billions will starve. Rather than collecting carbon tax to line certain unscrupulous pockets, governments should be re-greening the desert areas, as they will become the new prairies. There has not been too much CO2 in the past 270 million years, certainly not now.
Karmudjun
The comments here have run the gamut, I wish to only clarify a few points rather than contradict any previous comments. The RuBisCO error is not really an error - it is thought that when the photosynthesis evolved the Earth was a high CO2 and low O2 environment so having a sugar producing process in leaves using sunlight, CO2, and water was amazing in and of itself. The current photosynthesis process in a "high" O2 environment has already required further plant genetics (evolutionary pressure) to compensate for the O2 (and other metabolites) hanging around in the leaf cells. The enzymes work on concentration gradients, not on a one-way chemical pathway process. Photorespiration - the break down of sugars using O2 and producing CO2 is - for the most part - the enzymatic process following concentration gradients, or "just going backwards". Tackling this chemistry with plant genetics to tweak efficiency is awesome. Anything that speeds up the removal of metabolites from within the chloroplast or pumps them against the gradient with higher efficiency will help the plants and help the farmers. With higher yields, farmers can tolerate greater loss to pests and reduce their fertilizer & herbicide usage. If that is the case, this tweak of photosynthesis will not herald a "super kudzu" age, but reduce our dependence on petroleum based chemical enriched farming practices. I am not a pro-GMO person, I like the Mendelian approach to refining plant characteristics. This efficiency improvement - if performed within the food stock genetics and using food safe plant genetics - is spectacularly awesome!