Breaking News:Scientists Find Soil Fungus That Can Freeze Water and It Might Be Key to Engineering the Weather– What Just Happened

You might think water automatically turns to ice the moment the temperature drops below freezing. It’s not that you’ve been lied to by your high-school teacher. It’s more like you’ve been told only half the story.

Without a microscopic scaffold to build upon, water can remain liquid all the way down to a chilling -46 degrees Celsius (-50.8 degrees Fahrenheit). This phenomenon is known as supercooling. To freeze at warmer, below-zero temperatures, water needs a catalyst or “seed” to start the crystallization process.

Usually, this seed is a speck of mineral dust, soot, or a chemical particle drifting in the atmosphere. Water molecules latch onto this particle, arrange themselves into a rigid crystal, and trigger a snowball effect. As more molecules stick to the growing crystal, the ice becomes heavier and eventually falls to Earth.

But nature doesn’t just rely on dust. It also uses biological seeds. Scientists have known that certain bacteria are incredibly good at nucleating ice, for instance.

Now, prepare to meet the real master of the freeze.

An international team of researchers recently discovered that certain common soil fungi produce specialized proteins capable of freezing water at temperatures as warm as -2 degrees Celsius (28.4 degrees Fahrenheit). And unlike bacteria, which must be physically present as entire, bulky cells to form ice, these fungi secrete highly stable, water-soluble proteins that do the job completely on their own.

These cell-free fungal machines are so effective that they could soon replace toxic chemicals in weather modification (like cloud seeding for rain), revolutionize frozen food production, and drastically refine our global climate models.

The Anatomy of an Ice Maker

Scientists have known since the 1970s that certain bacteria can act as natural ice-makers. Bacteria use specialized proteins on their cellular membranes to grab water molecules and snap them into a rigid, icy grid^.

By the early 1990s, researchers realized that some fungi could perform this exact same trick. Yet, the underlying genetic machinery remained a mystery. Fungal DNA is not easy to work with, and it took modern advances in DNA sequencing to finally unpack their genomes.

The research team investigated a group of fungi known as the Mortierellaceae family. They extracted samples from water and lichens gathered during polar expeditions.

When the scientists sequenced the fungal DNA, they struck gold. They identified specific genes that looked remarkably similar to the ice-making genes found in bacteria. To prove these genes were actually responsible for creating ice, the team inserted them into completely different organisms, like yeast and E. coli.

Almost immediately, the engineered yeast and bacteria gained previously non-existent ice-making abilities. The transplanted genes worked perfectly.

A Microscopic Heist

How did a common soil fungus end up with the same ice-making equipment as a bacterium? The answer lies in horizontal gene transfer, the movement of genetic material between organisms other than by vertical transmission (parent to offspring).

Millions of years ago, an ancient fungal ancestor essentially stole the genetic blueprints from a neighboring bacterium.

“It is known that fungi can acquire genes from bacteria, but it’s not something that is common,” said Boris A. Vinatzer, an environmental scientist at Virginia Tech and co-author of the study. “So I never expected that this fungal gene had a bacterial origin.”

But the fungi also made their own tweaks to the bacterial blueprints. Bacterial ice nucleators are bulky. They rely heavily on the physical structure of the entire bacterial cell membrane to assemble properly and trigger freezing. If you disrupt the bacterial cell membrane, the freezing efficiency plummets.

The fungi, however, hacked the design. They evolved the protein to work independently of the cell membrane^{. They engineered a way to secrete these proteins directly into the environment as free-floating, soluble molecules.}

“Fungi use the same repetitive sequence architecture as bacteria for their ice-forming sites but have made them more soluble and stable, which probably benefits their ecological function,” explained Rosemary Eufemio, a biochemist at Boise State University and the study’s lead author.

Hacking the Weather Without the Toxins

Why do we care about how fungi freeze water? It’s useful because controlling ice means controlling the weather, and we need all the help and tools we can get.

When we artificially induce rain or snow, we use a process called cloud seeding. Particles are launched into the sky to give water molecules a surface to freeze onto. As the ice crystals grow heavier, they fall to Earth, melting into rain as they pass through the warmer atmosphere.

For the past 80 years, the go-to particle for cloud seeding has been silver iodide. It works well, but it is highly toxic to the environment.

These newly discovered fungal proteins offer a completely natural, non-toxic alternative. And because they are highly efficient and survive harsh conditions, they are perfect candidates for atmospheric engineering^.

“If we learn how to cheaply produce enough of this fungal protein, then we could put that into clouds and make cloud seeding much safer,” said Vinatzer.

A Cell-Free Advantage in Food and Medicine

Weather modification is just the beginning. The fact that these fungal proteins are cell-free gives them massive advantages over their bacterial counterparts in both food science and medicine.

Imagine trying to keep a delicate human organ safe during freezing, or trying to perfectly freeze a batch of strawberries without turning them to mush. You want the water to freeze at higher temperatures to protect delicate cellular structures.

Using bacteria to achieve this requires dumping entire, live bacterial cells into your food or medical supplies. That’s just not worth it for obvious reasons. Yet, because the fungal proteins operate independently of the fungal cell itself, scientists can cleanly isolate and purify them.

“That’s a big advantage in food production because you have just this one well-defined protein and you can get rid of everything else,” Vinatzer explained. “There is the possibility to develop a safe, effective additive that helps in the preparation of frozen food.”

This same logic easily applies to preserving biological tissues.

“Adding a fungal ice nucleator, which is a relatively small molecule, makes the water around the cell freeze much earlier before it gets very cold, to protect the delicate cell inside,” Vinatzer noted. “You couldn’t do that with the bacteria because you would have to add entire bacterial cells.”

Recomputing Our Climate Projections

There’s one more thing. Climate models rely heavily on understanding how clouds form, how much sunlight they reflect back into space, and how much heat they trap. The amount of ice in a cloud fundamentally changes its reflective properties, directly altering global temperatures.

Because these ice-making fungi live abundantly in common soils, the wind regularly sweeps their spores and secreted proteins into the atmosphere. We are likely vastly underestimating how much these microscopic fungal machines dictate daily weather patterns across the globe.

“Now that we know this fungal molecule, it will become easier to find out how much of these kinds of molecules are in clouds,” Vinatzer said. “And in the long run, this research could contribute to developing better climate models.”

The findings appeared in Science Advances.