More than 85% of land plants partner with fungi to pull nutrients from the soil in exchange for sugar, but never before has science witnessed a relationship between moss and fungi—until now.

For decades, science dubbed mosses the “loners” of the plant kingdom, despite their long 470-million-year history on Earth. After all, mosses are closely related to some of the earliest land plants, so they hold clues, if not remnants, of how life developed.

Science assumed that moss chose to remain single due to its small size and lack of roots. They were thought to be completely independent, as if they simply didn’t need fungi. However, a new study published in New Phytologist found that Earth’s green carpet may host fungi in its tissues, which had never been documented before.

UCR doctoral researcher Kian Kelly investigated this curious absence of fungi in moss by visiting scorching deserts, like the Mojave and Sonoran, where temperatures climb over 100 degrees Fahrenheit; there, he discovered that fungi were living inside mosses in both desert and less harsh conditions.

Once they started testing in the laboratory, they found a fascinating symbiosis between moss and fungi; it required a unique adaptation because moss doesn’t have roots, and given its physical makeup, scientists simply didn’t think fungi could even fit. But as it turns out, nature is interdependent.

If it can be scientifically proven that mosses and fungi team up, it could assist climate scientists in understanding how global shifts will affect this ancient land life, especially since this alliance might have aided life in crawling out of the ocean to begin with.

Fungi and moss, friends

Kelly first focused on “strange living communities” called biological soil crusts, which consist of fungi, bacteria, algae, mosses, and even microscopic animals.

While wandering through extreme heat in search of matching species, he sometimes couldn’t find the same moss species across different climates. He wondered if these climatic differences might affect the fungi inside the moss too, hoping to understand how climate change will continue to impact this lifeform.

Back in the lab, researchers identified fungal DNA living inside the moss tissue. They were surprised to find mycorrhizal fungi, which cannot survive without a plant partner. Furthermore, the fungi inside desert moss differed from those living inside mosses from more temperate climates.

“We suspect that certain fungi are more helpful for surviving hotter, drier climates,” Kelly said.

Another telling detail was that the fungi in the surrounding dirt didn’t match the species that chose to bond with the moss, suggesting a deliberate relationship was present. Once again, previous scientific assumptions were proven wrong. It appeared that fungi and moss were in cahoots, indeed.

Cool adaptation

Turning to microscopy next, Kelly stained the moss tissue with a blue dye that sticks to fungi, allowing him to witness branching fungal structures directly inside the moss cells. “As soon as I saw that, I knew we had something really interesting.”

The fungi looked like arbuscules—tiny, tree-shaped formations typically seen in plant roots—indicating a harmonious relationship. This is the case, at least, as far as scientists can gauge before further studies are conducted.

It appears as though the two organisms are exchanging nutrients. However, because mosses lack roots, these structures appeared instead in the moss leaves. The structure varied from root-bound fungi, which means a new visual model might make its way into textbooks, as this relationship had never before been documented.

If science can prove it exists, it could help scientists more fully understand the origins of life on this planet, as per a press release. Because mosses were among the planet’s first land inhabitants, this discovery might help science look back at the relationships that enabled life to survive on land. But the possibilities are somewhat endless in this case, as the findings might aid in the restoration of damaged landscapes. Many desert mosses are under threat, and conservationists might be able to better protect them with fungal boosts.

The study, published in New Phytologist, offers an unprecedented look at Earth’s “carpet,” one of the earliest forms of life on land. It shows that fungi might have teamed up with plant cells at life’s inception, and that deserts, though often overlooked, may hold the biggest surprises about life itself.

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