Earth’s Most Important Biochemical Reaction: Photosynthesis Breakthrough for Increasing CO2 Uptake in Plants

Plant cells Plant cells inside a leaf seen through a microscope.

A group of proteins in plant cells plays a vastly more important role in regulation of photosynthesis than once thought, according to new research at the University of Copenhagen. The research is an important step towards fully understanding photosynthesis regulation and increasing CO2 uptake in plants to benefit the climate.

Photosynthesis Facts

  • Photosynthesis is one of the most important biological processes on Earth, as it produces most of the oxygen in our atmosphere, upon which nearly all life depends.
  • Photosynthesis takes place in green plants, algae and some bacteria, when solar energy converts carbon dioxide and water into oxygen and organic matter in the form of glucose.
  • Glucose is then converted into nutrients and used by the plants themselves and animals
    Source: Den Store Danske

Imagine being able to grow plants that could absorb even more CO2 from Earth’s atmosphere and thereby help solve the world’s climate problems. Humans have selected, bred and optimized plants to increase food production and ensure our survival for thousands of years.

But the most important and fundamental function of life on Earth – photosynthesis – has not been relevant with regards to plant selection or breeding until now, an age when greenhouse gas emissions from human activities threaten our planet. With new technologies at hand, scientists around the world are now working to understand the internal processes of plants that drive photosynthesis.

In a new study published in the scientific journal PNAS, researchers from the University of Copenhagen’s Department of Plant and Environmental Sciences have just discovered that a group of proteins in plant leaf cells, called CURT1, plays a much more important role in photosynthesis than once thought. 

“We have discovered that CURT1 proteins control a plant’s development of green leaves already from the seed stage. Thus, the proteins have a major influence on how effectively photosynthesis is established,” explains Associate Professor Mathias Pribil, the study’s lead author.

Proteins that kickstart photosynthesis

CURT1 Protein Facts

  • URT1 is a protein group which coordinates structural processes of the internal chloroplast membrane that makes photosynthesis function more efficiently.
  • It was once thought that this protein group was only present in plants with mature leaves, and that the protein played a less important role. Scientists now know that the protein group is central to managing photosynthesis.
  • The protein group also helps plant leaves increase or decrease their light-harvesting ability depending upon sunlight strength.
  • Plants with a misbalanced CURT1 protein content – whether too many or too few – had a higher mortality rate and generally poorer growth.

CURT1 proteins were previously believed to play a more modest role and only be present in fully-developed leaves. But using state-of-the-art Imaging techniques (photography and computer equipment), the researchers zoomed 30,000x in on the growth of a series of experimental thale cress (Arabidopsis) plants. This allowed them to study the plants at a molecular level. The researchers could see that CURT1 proteins were present from the earliest stages of their plants’ lives.

“Emerging from the soil is a critical moment for the plant, as it is struck by sunlight and rapidly needs to get photosynthesis going to survive. Here we can see that CURT1 proteins coordinate processes that set photosynthesis in motion and allow the plant to survive, something we didn’t know before,” explains Mathias Pribil.

Photosynthesis takes place in chloroplasts, 0.005 mm long elliptical bodies in plant cells that are a kind of organ within the cells of a plant leaf. Within each chloroplast, a membrane harbours proteins and the other functions that make photosynthesis possible.

“CURT1 proteins control the shape of this membrane, making it easier for other proteins in a plant cell to move around and perform important tasks surrounding photosynthesis, depending on how the environment around the plant changes. This could be to repair light harvesting protein complexes when the sunlight is intense or to turn up a chloroplast’s ability to harvest light energy when sunlight is weak,” explains Pribil.

Plants with a misbalanced CURT1 protein content – whether too many or too few – had a higher mortality rate and generally poorer growth.

Improved CO2 uptake in the future

The new finding provides deeper insight into Earth’s most important biochemical reaction. Indeed, without plants, neither animals nor humans would exist on our planet. Thus far, the result only applies to the thale cress plant, but Pribil would be “very surprised” if the importance of CURT1 proteins for photosynthesis didn’t extend to other plants as well.

“This is an important step on the way to understanding all of the components that control photosynthesis. The question is whether we can use this new knowledge to improve the CURT1 protein complex in plants in general, so as to optimize photosynthesis,” says Mathias Pribil, who adds:

“Much of our research revolves around making photosynthesis more efficient so that plants can absorb more CO2. Just as we have selected and bred the best crops throughout the history of agriculture, it is now about helping nature become the best possible CO2 absorber,” says Mathias Pribil.

Reference: “Curvature thylakoid 1 proteins modulate prolamellar body morphology and promote organized thylakoid biogenesis in Arabidopsis thaliana” by Omar Sandoval-Ibáñez, Anurag Sharma, Michal Bykowski, Guillem Borràs-Gas, James B. Y. H. Behrendorff, Silas Mellor, Klaus Qvortrup, Julian C. Verdonk, Ralph Bock, Lucja Kowalewska and Mathias Pribil, 19 October 2021, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2113934118

Carbon EmissionsClimate ChangePhotosynthesisPlant SciencePopularUniversity of Copenhagen
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  • Ralph Gardner

    The earth is in is a 2.588-million-year ice age called the Quaternary Glaciation(fifth ice age) in a warm period called an interglacial period named the Holocene. The warm period is called an interglacial and usually lasts about 10,000 years between 90,000-year glacial periods. This one has lasted 11,700 years. https://en.wikipedia.org/wiki/Quaternary_glaciation Reducing CO2 will just make it colder. Already 4.5 million people worldwide die each year because of the cold compared to about 500,000 who die because of heat. https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(21)00081-4/fulltext

    • Torbjörn Larsson

      Man made global warming is happening much faster than natural warming, and for example even with increased CO2 – which was the article topic in cvase you forgot that in your trolling – it is uncertain if our food crops will thrive with the possible 3-4 deg C increase. It is also uncertain if the global climate will stay within the geological ice age.

      “Tipping points are now considered to have significant probability at today’s warming level of just over 1 degree C, with high probability above 2 degrees C of global warming.[6]

      Large-scale components of the Earth system that may pass a tipping point are called tipping elements.[7] At least 15 different elements of the climate system, such as the Greenland and Antarctic ice sheets, have been identified as possible tipping points.[8][9] A danger is that if the tipping point in one system is crossed, this could lead to a cascade of other tipping points.[10] If a cascade occurs, this could cause a hothouse Earth in which global average temperatures would be higher than at any period in the past 1.2 million years.[11]”

      [“Tipping points in the climate system”, Wikipedia]

      Your reference only show one consequence of global warming – increased mortality from regional “non-optimal temperatures” whether weather of climate – which is not in the direction you want it to go.

      “Interpretation
      Non-optimal temperatures are associated with a substantial mortality burden, which varies spatiotemporally. Our findings will benefit international, national, and local communities in developing preparedness and prevention strategies to reduce weather-related impacts immediately and under climate change scenarios.”

      “Earth’s average surface temperature has risen at a rate of 0·07°C per decade since 1880, a rate that has nearly tripled since the 1990s.1 The acceleration of global warming has resulted in 19 of the 20 hottest years occurring after 2000 and an unprecedented frequency, intensity, and duration of extreme temperature events, such as heatwaves, worldwide. Exposure to non-optimal temperatures has been associated with a range of adverse health outcomes (eg, excess mortality and morbidity from various causes).2, 3, 4, 5, 6”

      “Our study also explored the temporal change in temperature-related mortality burden from 2000 to 2019. The global daily mean temperature increased by 0·26°C per decade during this time, paralleled with a large decrease in cold-related deaths and a moderate increase in heat-related deaths. The results indicate that global warming might slightly reduce the net temperature-related deaths, although, in the long run, climate change is expected to increase mortality burden. ”

      “Several assumptions and limitations should be acknowledged. ”

      If you are interested in decrease mortality burden, you should according to science expectation, do something about the man made global warming we observe, not speculate against expectations that the result will be better.

      Even better, you could aim your reading to the topic at hand.

  • Sivakumar C V

    Can’t this photosynthesis be simulated artificially?/Is that process can’t be cloned?

    • Torbjörn Larsson

      I’m not sure if we have lab systems of photosynthesis like we have with some other cellular processes. And here they are looking at development factors to boot.

      I read earlier today of the effort to understand how cyanobacteria can do it in red light when under a plant canopy, and it was a near decade effort that in the end saw a small molecular change.

      “Using high-resolution cryo-electron microscopy (cryo-EM), the researchers pinpointed locations in two photosystem complexes within the cyanobacteria that incorporate alternate versions of chlorophyll pigments. These alternates are attuned to longer wavelengths, which allows the cyanobacteria to efficiently use far-red light to perform oxygen-evolving photosynthesis. Considering that the energy available in far-red light is equivalent to 15% of total solar radiation reaching Earth, this ability gives these organisms an advantage in competing with plants and other cyanobacteria for light for photosynthesis.”

      “”If you would have asked me 10 years ago if you could grow most cyanobacteria in far-red light, I would have laughed,” said Donald A. Bryant, Ernest C. Pollard Professor in Biotechnology and professor of biochemistry and molecular biology at Penn State, and the leader of the research team. “But it turns out that if you put them in far-red light, some cyanobacteria activate a set of about 20 genes that allow them to modify their photosynthetic apparatus and the chlorophylls that they produce so that they can use far-red light for photosynthesis. Since making that discovery in 2013, we have been trying to understand how that works.””

      “”We knew from isolating and characterizing the complexes that photosystem I contains seven to eight chlorophyll f molecules, and that photosystem II contains one chlorophyll d molecule and four to five chlorophyll f molecules, along with about 90% of the original chlorophyll a, so we wanted to know where those changes occurred in the complexes,” said Bryant. “One way to figure that out is to determine the structure of the complexes, but because they are so large and complex—and the chemical differences are so minor—it was extremely challenging.””

      “”My collaborator, Chris Gisriel, who is a postdoctoral fellow in Gary Brudvig’s lab at Yale, was fortunate to achieve a very high-resolution structure for the photosystem II complex—2.25 angstrom (Å)—allowing him to visualize the differences in some of the chlorophylls directly,” said Bryant. “The extent of the difference between chlorophyll a and f is that two hydrogen atoms are replaced by an oxygen atom in a molecule with the composition of C55H72MgN4O5. In a complex like photosystem I that contains nearly 100 pigment molecules and 11 protein subunits or photosystem II with 35 chlorophylls and 20 protein subunits, these small changes are like looking for a few needles two very large haystacks. Because these chlorophylls confer the special properties that allow far-red light utilization, it is very important to understand exactly how these molecules are arranged.””

      [ https://phys.org/news/2021-12-photosystems-ii-growth-far-red.html ]

      [As an aside, the solar luminosity at the 800 nm peak absorption of these oxygenating photosynthesizers overlap with the spectral luminosity peak of some M stars, so it has bearing on whether we expect to see biosphere oxygen release on habitable planets around such stars. I.e. since these guys can live on the same luminosity levels, we can indeed expect that it could happen elsewhere! An oxygenated atmosphere allows for more complex life…]

  • Robert Adams

    Anyone who thinks humans burning coal has no effect on the atmosphere should read this:
    Scientists have known burning coal warms the climate for a long time. This 1912 headline proves it.
    Popular Mechanics in 1912 explained that spewing CO2 into the air “tends to… raise its temperature.” We’ve known it since the 1850’s. Margaret Thatcher accepted it. Richard Nixon accepted it. Then it became ideological.
    https://archive.thinkprogress.org/headlines-back-in-1912-warned-coal-consumption-affecting-climate-b0c1373194a1/

  • Frankie Ku

    About 10 years ago giant poplar trees developed were to be a lot of help. Perhaps their stored carbon and other factors negate their usage. Burning carbon then storing CO2 is just too expensive for now. Same for green H2. Chinese report today say that is decades away.