Rosa Rubicondior: Unintelligent Design - How an Intelligent Designer Could Have Made Photosynthesis More Efficient

Phaeoceros laevis, a species of hornwort commonly known as smooth hornwort.

Credit: Des Callaghan

This odd little plant could help turbocharge crop yields - Boyce Thompson Institute

Scientists led by researchers at the Boyce Thompson Institute (BTI), Cornell University, and the University of Edinburgh have discovered a plant with a neat trick that makes photosynthesis more efficient and which, if replicated in crop plants, could enhance food production. They have just published their findings in the journal Science. The trick makes the ubiquitous enzyme RuBisCo (ribulose-1,5-bisphosphate carboxylase/oxygenase) more efficient — or perhaps it would be more accurate to say less inefficient, because it is probably one of the least efficient enzymes in the whole of nature, something that ought to be acutely embarrassing for any advocate of intelligent design who understands it.

A fundamental belief of creationism is that all living things were created for the benefit of humankind on a planet supposedly designed for humans to live on. If that were so, it is reasonable to assume that such a planet would be organised to supply humans with food in the most efficient and productive way possible. Yet here we have an example of one plant possessing something that, had all plants been given it, would have been massively beneficial to humans.

So, did creationism's putative omnibenevolent designer choose not to incorporate this feature into our food crops, or did it simply forget? This is the sort of question that always goes unanswered by creationists, who mutter vaguely about 'mysteries' and 'not knowing the mind of God' — the same god they assure us has a plan for all of us, and whose wishes they somehow claim to know in detail.

First, a little about RuBisCo, from my book The Unintelligent Designer: Refuting The Intelligent Design Hoax:

RuBisCo is the enzyme in photosynthesis responsible for taking carbon dioxide (CO₂) from the atmosphere and building the chains of carbon in sugars which form the backbone of all organic substances.

But RuBisCo is incredibly bad at doing what it does; only carrying out about three reactions a second against tens of thousands of reactions a second for some enzymes. And it makes lots of mistakes. It finds it difficult to tell oxygen molecules (O₂) from CO₂ and often incorporates it by mistake, causing a chain reaction which causes a loss of carbon and wastes energy. To make matters worse, RuBisCo can end up making xylulose-1,5-bisphosphate which actually inhibits it!¹ Some plants have evolved mechanisms for reducing these mistakes – normally by keeping O₂ out of the way – but they appear to have evolved several times, independently and none of them are especially successful.

The origin of this problem is that RuBisCo itself evolved in an oxygen–free atmosphere, so the potential to make this mistake was not a factor natural selection could take into account. Unlike the way an intelligent, omniscient designer would work, natural selection acts on what is, and the here and now, not on what might happen later. Evolution can’t pop into the future and see how things turn out and it has no reverse gear. But an omniscient, omnipotent designer would know in advance how things were going to turn out. And if it did make a mistake an intelligent designer would be capable of scrapping the design and starting again.

No omniscient, intelligent designer would blunder blindly into a problem of its own making and then find itself stuck with the problem, unable to go back and start gain and having to make do with massive inefficiency and massive waste.

Having started off down the road to photosynthesis, and having given evolving life forms such a tremendous advantage, despite the inefficiency, there was no going back. Any tendency to change it would result in something even worse, so living things have to make do with what they have got. No planning; no ability to go in reverse, and no one to stand back and think of a better way, and start again. The fact that several plants have evolved different ways to compensate for RuBisCo's inefficiency shows that it is not ideal for purpose. No omnipotent intelligent designer would come up with something which has to be compensated for. On its own, RuBisCo, more than any other phenomenon in the natural world, dispels any notion of intelligent design.

The Unintelligent Designer: Refuting The Intelligent Design Hoax, pp. 93-94

The researchers discovered that a species of hornwort, Phaeoceros laevis, like several species of algae, concentrates RuBisCo in small compartments surrounded by CO₂. They also showed that, unlike the genetic system controlling this process in algae, the genes responsible in hornwort can be successfully transferred to other plants, because hornworts share a more recent evolutionary history with crop plants than algae do.

The team's research and its significance for food production are explained in a Boyce Thompson Institute news item:

This odd little plant could help turbocharge crop yields
An international team of researchers has uncovered a remarkable molecular trick used by a unique group of land plants, one that could eventually be engineered into crops like wheat and rice to dramatically boost how efficiently they convert sunlight into food.
The study, led by researchers at the Boyce Thompson Institute (BTI), Cornell University, and the University of Edinburgh, focuses on a fundamental problem in agriculture: the enzyme responsible for capturing carbon dioxide from the air during photosynthesis—called Rubisco—is slow and inefficient.

Rubisco is arguably the most important enzyme on the planet because it’s the entry point for nearly all carbon in the food we eat. But it’s slow and easily distracted by oxygen, which wastes energy and limits how efficiently plants can grow.

Professor Fay-Wei Li, co-senior author.
Boyce Thompson Institute
Ithaca, NY, USA.

Some organisms have evolved a clever workaround. Many species of algae pack Rubisco into tiny, specialized compartments inside their cells called pyrenoids—essentially microscopic bubbles that concentrate carbon dioxide around the enzyme, helping it work far more efficiently.

Scientists have long dreamed of installing this turbocharging system into food crops, which lack pyrenoids. But algae machinery has proven stubbornly difficult to transfer.

The breakthrough came from studying hornworts—the only land plants known to possess CO₂-concentrating compartments similar to those in algae. Because hornworts share a more recent evolutionary history with crops than algae do, the research team hypothesized their molecular machinery might transfer more readily. What they found was unexpected.

We assumed hornworts would use something similar to what algae use—a separate protein that gathers Rubisco together. Instead, we discovered they’ve modified Rubisco itself to do the job.

Tanner A. Robison, co-first author. Boyce Thompson Institute
Ithaca, NY, USA.

The key is an unusual protein component the researchers have named RbcS-STAR. Rubisco is assembled from large and small protein pieces. In hornworts, one version of the small piece carries an extra tail—the STAR region—that acts like molecular velcro, causing Rubisco proteins to constellate.

To test whether STAR could work outside its native hornwort, the team conducted a series of experiments. First, they introduced RbcS-STAR into a closely related hornwort species that lacks pyrenoids. The result: Rubisco reorganized from a scattered distribution into concentrated, pyrenoid-like structures.

They then tried the same experiment in Arabidopsis, a plant commonly used in lab research. Again, Rubisco formed dense compartments inside the plant’s chloroplasts.

We even tried attaching just the STAR tail to Arabidopsis’s native Rubisco, and it triggered the same clustering effect. That tells us STAR is truly the driving force. It’s a modular tool that can work across different plant systems.

Professor Alistair J. McCormick,
Institute of Molecular Plant Sciences
School of Biological Sciences
University of Edinburgh
Edinburgh, UK.

This transferability is what makes the finding so significant for agriculture. It suggests that researchers may be able to trigger Rubisco clustering in crop plants by introducing a single universal velcro, rather than going through haute couture.

The researchers note that challenges remain. A series of ductwork are now needed to deliver CO₂ to Rubisco.

We have built a Rubisco house, but it won’t be an efficient house unless we update the HVAC.

Assistant Professor Laura Gunn, co-senior author.
Plant Biology Section
School of Integrative Plant Science
Cornell University
Ithaca, NY, USA.

The team is now working to address this challenge.

Still, the discovery marks an important advance in a field with enormous potential impact. Improving photosynthetic efficiency even modestly could increase crop yields while reducing agriculture’s environmental footprint—a crucial goal as the world works toward more sustainable food production.

This research shows that nature has already tested solutions we can learn from. Our job is to understand those solutions well enough to apply them where they’re needed most—in the crops that feed the world.

Professor Fay-Wei Li

The study was published in Science, with equal contributions from four early-career scientists: Tanner A. Robison, Yuwei Mao, Zhen Guo Oh, and Warren S.L. Ang. The corresponding authors were Laura H. Gunn, Alistair J. McCormick, and Fay-Wei Li.

Publication:
Tanner A. Robison et al.
An unconventional Rubisco small subunit underpins the CO₂-concentrating organelle in land plants.
Science 391, 1070-1075 (2026). DOI:10.1126/science.aea0150

Abstract
In many algae, photosynthesis is boosted by biophysical CO₂-concentrating mechanisms, which pack the CO₂-fixing enzyme Rubisco into liquid-like organelles called pyrenoids. Engineering C₃ crops with algal pyrenoids could increase yields, but progress is hampered by the deep evolutionary divide between crops and algae. Here, we show that hornworts, the only land plants with pyrenoids, have an unusual Rubisco small subunit, RbcS-STAR, the C-terminal coiled-coil domain of which oligomerizes to mediate Rubisco condensation. RbcS-STAR is incorporated into the Rubisco holoenzyme and thus acts as an “innate” Rubisco linker. Expression of RbcS-STAR in pyrenoid-lacking species, including Arabidopsis, is sufficient to induce pyrenoid-like condensates. Our findings reveal a mechanism for Rubisco condensation and a potential route to introduce pyrenoids into crop plants.

If the mechanism found in this small and rather unassuming hornwort can now be transferred into crop plants by human researchers, an obvious question arises for anyone who believes in an all-knowing designer: why was this not done in the first place? Human scientists, working with limited knowledge and imperfect tools, can identify a more efficient arrangement and begin transferring it into the plants that feed the world. An omniscient and omnipotent designer, however, would supposedly have had both the knowledge and the ability to incorporate such an improvement from the outset. The fact that it was not there suggests that the inefficiency of RuBisCo and the need for work-arounds are not the results of intelligent planning but of historical contingency — the hallmark of evolutionary processes.

Indeed, the very existence of mechanisms that partially compensate for RuBisCo’s inefficiency in different groups of plants and algae points strongly in that direction. Evolution does not redesign systems from scratch; it tinkers with what already exists. The hornwort strategy is simply one more example of that tinkering, an evolutionary workaround that happens to provide a particularly promising template for improving modern crops. It is precisely the sort of patch-up solution we expect from a process constrained by history, but not something we would expect from a supposedly perfect and foresighted designer.

Equally telling is how the researchers arrived at this discovery. Their reasoning was guided entirely by evolutionary theory. Earlier attempts to transfer the carbon-concentrating machinery of algae into crop plants had failed, but evolutionary relationships suggested a better candidate. Because hornworts share a more recent common ancestry with flowering plants than algae do, the researchers predicted that the genetic machinery responsible for concentrating CO₂ around RuBisCo would be more compatible with crop plants. That evolutionary prediction proved correct.

So far from shaking scientists’ confidence in evolution — as creationists have confidently predicted for more than half a century — discoveries like this depend upon it. Evolutionary theory not only explains why biological systems are often inefficient and historically constrained; it also helps scientists find practical solutions to those limitations. In this case, a tiny hornwort has provided a clue that could one day help feed millions more people — a discovery made possible not by abandoning evolutionary theory, but by applying it.

Creationists will now need to either ignore the question, if humans scientists can do this, why was it apparently beyond the capabilities of their putative creator god? Or they will pretend to be too stupid to understand the question.

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