Ancient protein Rubisco could be used to save future food crops from dying in hot climates

When it comes to food, humanity is looking down the barrel of a gun. The world population will grow to nearly 9.8 billion people by 2050, resulting in an expected 60% increase in food demand. And the devastating effects of climate change do not bode well for our agriculture.

But there may be a silver lining, and it’s related to reverse evolution.

Researchers at Cornell University have found a way to revive an ancient form of enzyme called Rubisco that fueled photosynthesis in plants millions of years ago, when the Earth was going through one of these climates hottest since the last 50 million years. In a study published April 15 in the journal Scientific advance, researchers were able to use present-day versions of Rubisco to piece together the idea of ​​this enzyme in antiquity. Therefore, scientists can harness its power once again to help ensure our crops in the future can adapt to and fight climate change and provide us with all the fresh fruits, vegetables and grains that we need.

Although plants take up carbon dioxide and produce oxygen, they cannot just use carbon dioxide in its present gaseous form. Rubisco, which stands for ribulose-1,5-bisphosphate carboxylase/oxygenase and is the most abundant enzyme found on Earth, turns carbon dioxide into a bio-friendly form that plants use to build tissues of them.

One problem with Rubisco is that it also interacts with oxygen. This unwanted mating produces toxic by-products that slow down photosynthesis and prolong the duration, affecting crop yields. Scientists have stopped finding ways to mitigate this problem and improve crop yields by genetically modifying plants to create a form of enzyme derived from algae or other tweaks. But these efforts have yet to bear fruit.

To address this conundrum, researchers at Cornell took a trip back to memory — 25 to 50 million years ago when the Earth was much hotter thanks to high levels of carbon dioxide in the atmosphere (a a whopping 500 to 800 parts per million, compared with an estimate of 413 ppm in 2020). This means that today’s Rubisco may have an ancestral version that has been adapted to operate under such extreme carbon dioxide levels.

The Cornell team recreated a phylogenetic diagram, a tree-like diagram to trace evolutionary relationships between members and show how they evolved from a common ancestor. They did this by analyzing the Rubisco genes in plants of the Solanaceae (beetle) family, which includes potatoes, pepper, tomatoes, eggplant and tobacco. And from this family, the researchers were able to generate and evaluate the biological activity of nearly a hundred of these potential ancient Rubiscos in the lab using bacteria. E coli.

Courtesy Cornell University

“By getting more [genetic] Maureen Hanson, a molecular biologist at Cornell and lead author of the new study, said in a press release it’s possible to build Rubisco chains in existing plants to figure out which types of Rubiscos are likely to be. existed 20 to 30 million years ago. “We were able to identify ancestral enzymes that were predicted to be superior in quality to present-day enzymes.”

The team’s next big step is to transfer replicated versions of the Rubisco gene into Solanaceae plants such as tomatoes and potentially others like rice or soybeans and see if photosynthetic activity improves. and improve crop yield.

“For the next step, we wanted to replace the genes for the existing Rubisco enzyme in tobacco with these ancestral sequences using CRISPR. [gene-editing] Hanson said. “We certainly hope that our experiments will show that by adapting Rubisco to today’s conditions, we will have more productive crops.”

For a stressful planet with lots of hungry mouths to feed on, that seems like a good start.