Computer model of plants’ carbon-concentrating mechanism could unlock new approach to boosting crop yield
PRINCETON UNIVERSITY
A new study provides a framework to boost crop growth by incorporating a strategy adopted from a fast-growing species of green algae. The algae, known as Chlamydomonas reinhardtii, contain an organelle called the pyrenoid that speeds up the conversion of carbon, which the algae absorb from the air, into a form that the organisms can use for growth. In a study published May 19, 2022 in the journal Nature Plants, researchers at Princeton University and Northwestern University used molecular modeling to identify the features of the pyrenoid that are most critical for enhancing carbon fixation, and then mapped how this functionality could be engineered into crop plants.
This isn’t just an academic exercise. For many people today, the bulk of food calories come from crop plants domesticated thousands of years ago. Since then, advancements in irrigation, fertilization, breeding and the industrialization of farming have helped feed the burgeoning human population. However, by now only incremental gains can be extracted from these technologies. Meanwhile, food insecurity, already at crisis levels for much of the world’s population, is predicted to worsen due to a changing climate.
New technology could reverse this trend. Many scientists believe the algal pyrenoid offers just such an innovation. If scientists can engineer a pyrenoid-like ability to concentrate carbon into plants such as wheat and rice, these important food sources could experience a major boost to their growth rates.
“This work provides clear guidance for engineering a carbon-concentrating mechanism into plants, including major crops,” said Martin Jonikas, a senior author of the study who is an associate professor of molecular biology at Princeton and an investigator at the Howard Hughes Medical Institute.
Chlamydomonas reinhardtii achieves carbon fixation due to the action of the enzyme Rubisco, which catalyzes the conversion of CO2 into organic carbon.
Terrestrial plants also use Rubisco to accomplish carbon fixation, but in most plants, Rubisco only works at about a third of its theoretical capacity because it cannot access enough CO2 to operate faster. Much effort has therefore gone into studying the carbon-concentrating mechanisms, particularly those found in cyanobacteria and in Chlamydomonas, with the hope of eventually providing this function for terrestrial crop plants. But there’s a problem:
“While the structure of the pyrenoid and many of its components are known, key biophysical questions about its mechanism remain unanswered, due to a lack of quantitative and systematic analysis,” said senior co-author Ned Wingreen, Princeton’s Howard A. Prior Professor of the Life Sciences and professor of molecular biology and the Lewis-Sigler Institute of Integrative Genomics.
To gain insights about how the algal pyrenoid carbon-concentrating mechanism works, Princeton graduate student Chenyi Fei collaborated with undergraduate Alexandra Wilson, Class of 2020, to develop a computational model of the pyrenoid with the help of co-author Niall Mangan, assistant professor of engineering sciences and applied mathematics at Northwestern University.
Prior work has shown that the Chlamydomonas reinhardtii pyrenoid consists of a spherical Rubisco matrix traversed by a vasculature of membrane-enclosed projections called pyrenoid tubules, and surrounded by a sheath made of starch. It’s thought that CO2 taken up from the environment is converted into bicarbonate and then transported into the tubules, where it then enters the pyrenoid. An enzyme present in the tubules converts bicarbonate back into CO2, which then diffuses into the Rubisco matrix. But is this picture complete?
“Our model demonstrates that this conventional picture of the pyrenoid carbon-concentrating mechanism can’t work because CO2 would just rapidly leak back out of the pyrenoid before Rubisco could act on it,” Wingreen said. “Instead, the starch shell around the pyrenoid must act as a diffusion barrier to trap CO2 in the pyrenoid with Rubisco.”
In addition identifying this diffusion barrier, the researchers’ model pinpointed other proteins and structural features needed for CO2 concentration. The model also identified non-necessary components, which should make engineering pyrenoid functionality into plants a simpler task. This simplified model of the pyrenoid, the researchers showed, behaves similarly to the actual organelle.
“The new model developed by Fei, Wilson, and colleagues is a game changer,” said Alistair McCormick, an expert in Plant Molecular Physiology and Synthetic Biology at the University of Edinburgh, who has worked with the Princeton scientists but was not involved in this study.
“One of the key findings of this paper, which differentiates the Chlamydomonas carbon-concentrating mechanism from those found in cyanobacteria, is that introducing active bicarbonate transporters may not be necessary,” McCormick said. “This is important because active bicarbonate transport has been a key challenge hindering progress in the engineering of biophysical carbon-concentrating mechanisms.”
The study, “Modeling the pyrenoid-based CO2-concentrating mechanism provides insights into its operating principles and a roadmap for its engineering into crops,” by Chenyi Fei, Alexandra T. Wilson, Niall M. Mangan, Ned S. Wingreen, and Martin C. Jonikas, was published in Nature Plants.
Funding for this research was provided by the National Institutes of Health, National Science Foundation, Simons Foundation, and Howard Hughes Medical Institute.
JOURNAL
Nature Plants
DOI
METHOD OF RESEARCH
Computational simulation/modeling
ARTICLE TITLE
Modeling the pyrenoid-based CO2-concentrating mechanism provides insights into its operating principles and a roadmap for its engineering into crops
ARTICLE PUBLICATION DATE
19-May-2022
COI STATEMENT
The authors declare no competing interest.
The only food insecurity I’m aware of is that caused by political choices, same as for decades now.
If people starve now it’s due to someone’s policy choices.
Because governments so often act in support of those with the most money, ignoring the rest of us, policies might be significantly enabling this trend but if so I would guess it is in support of the cash flow, not support of the particular results.
This article, which says world hunger has been increasing rapidly since 2015, in step with increasing crop yields, presents an interesting and unsettling view of how things might collapse very suddenly. It has nothing to do with climate change and only little to do with the reduction of nitrogen fertilizers from political conflicts and stupid net zero activities. It could happen due to totally different factors because the system that rules is very susceptible to instabilities of various kinds. I know it is from the Guardian but dismissing it as irrelevant requires pointing out where it is wrong.
https://www.theguardian.com/commentisfree/2022/may/19/banks-collapsed-in-2008-food-system-same-producers-regulators
The Guardian makes money from clicks. I refuse to support that horrible propaganda machine in every way possible including my single click. They have damaged this world beyond measure.
I’m sorry but you’ll have to find a source for your (excellent) point elsewhere for me to read it unfortunately.
I would suggest the first paragraph equally applys to health care. While doctors purportedly subscribe to the Hippocratic oath, corporations do not. But corps are now incharge of health care. No wonder service decreases and costs increase.
“Meanwhile, food insecurity, already at crisis levels for much of the world’s population, is predicted to worsen due to a changing climate.”
Person does not have a clue about current crop yields or what’s going on the world outside their comfy air conditioned office.
And do they really think the people wetting themselves about climate change are going to accept more GMO foods??
Increasing the atmospheric CO2 process should be helpful in overcoming the described problem:
“Our model demonstrates that this conventional picture of the pyrenoid carbon-concentrating mechanism can’t work because CO2 would just rapidly leak back out of the pyrenoid before Rubisco could act on it,” Wingreen said. “Instead, the starch shell around the pyrenoid must act as a diffusion barrier to trap CO2 in the pyrenoid with Rubisco.”
The word Model is enough to put me off.
What about a practical demonisation.
Michael VK5ELL
The use of computer models to understand chemical processes has a decades old history. It usually works as the lowest mechanisms they are modeling are well-understood.
Of course, once you have found you idea works in theory you need to prove it works in practice. But understanding the theory makes the amount of trial and error required to get it to work a lot less.
Plants take time to grow, It makes sense to simulate what you are trying to achieve first.
We usually say that modeling a theory gives us a better understanding of what to measure when we are looking into real systems. Hopefully some experimentalists are now taking the model output and designing a way to measure the key findings. Of course if they follow the global warming model, they will modify the measurements to comport with the model outputs.
Only the tin hat brigade like Prince Charlie and fellow eco-loons worry about GMO crops
Interesting that they find that the algae absorb carbon from the air.
Are they talking about particulates from exhaust pipes then?
Or is this just more sloppy writing, and they mean CO2?
It’s EurekaAlert. Sloppy writing should be assumed.
Of course, silly me, I was forgetting.
Minimizing food spoilage from field to table would solve most of the problem. As it is, only 25% (or less) of the food produced is actually consumed. Ask your grocer about the quantity of bananas they toss every day.
Near the end: “The model also identified non-necessary components”. Mmmhmmm. Reminds me of people embarrassing themselves not too long ago by talking about “junk DNA” in our genome. “We don’t understand what it does so it must be junk”. A wiser, humbler approach would be, “We don’t yet understand what it does, but it most likely isn’t junk.”
The only “climate change” that will be effecting agriculture in the coming decades will be a much shorter growing season due to both late frosts in the Spring and early frosts in the Fall. We are seeing it this year, especially in North and South America. Brazil/Argentina are recording record colds (end of their Fall) and the US and Canada can’t plant due to the wet/cold (and even snow). Then throw in high diesel and fertilizer prices.
It’s going to be a hard go of it and the possibility of millions of people being effected is very real. And as usual, the people at the bottom of the economic ladder will suffer the most.
Yes, rba: as I have said loads of times around here based on my 60+ year experience of UK farming.
e.g. How it is near impossible now to grow a crop of even (short-growing-season) Spring Barley any more whereas as 50+ years ago UK farmers, even as far as 55° North, could successfully plant and harvest Spring Wheat, with its 4 week longer season and they did it without needing crop dryers.
Repeat:”Deserts are cold places with unpredictable weather/climates – don’t go making them because once you have, you can not un-make them.
btw: Why do we see a picture of wheat, or is this some sort of (unfunny) humour
Wheat is not = Food
Plants put things called Lectins (aka Proteins or Glutens) inside of themselves as a defence against being eaten.
Not that it would defend any given plant from being eaten ‘the first time’
But that those hideous proteins would make the plant’s consumer so poorly, ill or dead that said consumer would not come back and eat any more..
And you do not get anything more hideous than (short straw/dwarf) Wheat Gluten
Thank you Norman Borlaug – you’re right up there with Ancel Keys
Wasted effort. The limiting factor is CO2. If Greens have their way there will be reduced levels of CO2 to deliver to that enhanced plant.
It feels like the authors have never heard of C4 plants, e.g. maize. These already concentrate CO2.
It is wasted effoirt, but co2 is not the rate limiting factor in nutrient production. Most co2 fixation goes iinto the production of structural carbs (vegetative growth). Nitrogen acquisition is the the rate limiting factor in nutrient production– and even that’s a complex feedback relationship. As any gardener knows, too much N fertilizer encourages vegetative growth and inhibits fruiting..and fruits are where the nutrition is….We may be omnivores, but not grazers or browsers.
I have a pond surrounded by forest that gets choked with algae. The algae gets its carbon much more from forest detritus than atmospheric CO2. When I keep the pond clean of leaves the algae doesn’t grow. If the pond is full of leaves when I treat the pond with microbes that hasten the decomposition of the leaves the algae growth slows. When I run the pond’s aerator thus adding more oxygen and atmospheric CO2 the algae growth stops..
This is rather intriguing! If it’s true, it means higher efficiency – you don’t have to farm as much land to have the same yield. Good all around!
At least molecular modelling isn’t climate modelling. This technique has a long history and many successful examples of validation against real world observations. So refreshing to read the word modelling in a context that is truly scientific. As to whether this will truly play a role in averting or addressing growing food insecurity that is largely due to incompetent, frankly idiotic government policy and the fake climate change religion, I have my doubts.
“The model also identified non-necessary components”
What could go wrong?
No one is asking why the pyrenoids have disappeared in higher plant evolution. No one is asking what for the actual plants would need more carbohydrate than what they already fix. Growth of organisms is the outcome of an integrated multitude of processes. I wonder if rice plants fixing more CO2 would make more seeds or growing fatter stems… Same reasonng for any other species.
Shallow minds leading “research” (spending?) programs…
Sometimes potentially detrimental changes can occur, either tied to an advantageous change, or because there is no immediate disadvantage.
That particular change may have occurred when CO2 levels were much higher, and it had little impact.
It would certainly be interesting to see what the result would be if this change can be made in real plants.
I doubt they will develop 3 strong roots and become motile.
I Thought algae is going to be the new bio-fuel replacing ethanol AND EV’S. Check out The Auto Channel they KNOW it is!