Takakia, a moss with a 390-million-year lifespan, may be found in some of the planet’s most inaccessible regions, such as the ice cliffs of the Tibetan Plateau. A group of scientists spent a decade searching the world’s highest peaks for Takakia, first sequencing the moss’ DNA, and researching the effects of climate change on the moss.
Takakia is a genus of mosses that belongs to the Takakiaceae family. It is considered to be one of the most primitive and unique moss genera, as it exhibits several features that distinguish it from other mosses. Takakia species are often found growing in cold, high-elevation habitats, such as alpine regions and polar areas.
Takakia is one of the quickest evolving organisms ever investigated, according to their findings, which were published in Cell, but it is probably not changing quickly enough to survive climate change.
A tiny, slowly-growing moss called takakia is only found in a few small areas on the Tibetan Plateau, as well as in Japan and the US. To reach the moss’s 4,000-meter-high habitat in the Himalayas, gather samples, and analyze its environment, the researchers underwent 18 excursions.
“We set out to describe and analyze a living fossil,” says author Ralf Reski, a plant biotechnologist at the University of Freiburg in Germany.
“In the Himalayas, you can experience four seasons within a day,” adds plant biologist and co-expedition leader Ruoyang Hu, a member of the team from Capital Normal University in China. “At the foot of the mountain, it is sunny and clear. When you get to the halfway point, there is always a light rain it feels like you’re walking in a cloud. And when you get to the top, it snows and it’s very cold.”
“Only half of the road is accessible by drive. We had to climb up the remaining way,” says co-expedition leader and fellow plant biologist at Capital Normal University, Xuedong Li.
Our prediction shows that suitable conditions regions for Takakia will shrink to only around 1,000-1,500 square kilometers all over the world at the end of the 21st century.
Ruoyang Hu
When the Himalayas rose up beneath Takakia, it was already 100 million years old. This drastically altered its habitat, pushing it to adapt swiftly, which it did.
“The idea was to go as deep as possible into the history of the first land plants to see what they can tell us about evolution,” says Reski. “We found that Takakia is currently the genome with the highest number of fast-evolving genes. It’s very active on the genetic level.”
The study discovered that over many generations of selection, Takakia’s vast genome evolved to become particularly good at mending damaged DNA and repairing UV damage, among other things.
“Takakia plants are covered with heavy snow for eight months each year, and then are subjected to high-intensity ultraviolet radiation during the four-month light period,” says Yikun He, author and fellow plant biologist at Capital Normal University. In response, the plants adapted the ability to grow in different locations using a flexible branching system. “As a result, this continuous branching forms a network structure and a very sturdy population structure, which can effectively resist the invasion of heavy snowstorms.”
Sequencing Takakia’s genome also helps to end a longstanding debate about its classification. “People wondered, is it really a moss? Or is it something like an alga or a liverwort? Because it has a combination of ancient traits,” says Reski, “but our work shows that it’s a moss.”
While Takakia’s genome has changed dramatically over time, its morphology has barely changed. “You normally would think, if you have a lot of mutations in your genome, at some point the form would change. We hope these findings will inspire a whole new field of study evolution involving changing genomes and static morphology,” says Reski.
The scientists also used technology to study the “microclimate” of the plant, satellite weather data, and timelapse cameras to examine the bigger environmental changes taking place in the larger ecosystem.
They discovered that the plateau’s glaciers were swiftly melting and that the temperature was constantly warming. They also noted that there is more UV radiation than ever before reaching the moss.
Studies the team performed in the lab showed that the level of UV radiation Takakia now experiences is enough to kill even other plants adapted for harsh environments.
In addition, the researchers noted that despite the moss’s past success in rapid adaptation, it’s becoming increasingly hard to find, even for experts like Li and Hu. In fact, they found that Takakia populations in Tibet decreased by around 1.6% each year over the course of their study.
“Our prediction shows that suitable conditions regions for Takakia will shrink to only around 1,000-1,500 square kilometers all over the world at the end of the 21st century,” says Hu. The authors agree that the moss likely won’t survive another 100 years.
The scientists propose teaching the public about less well-known species like Takakia to aid in the moss’s chances. They also suggest a global initiative to pool resources so that scientists can continue researching the moss and taking precautions to conserve it, like growing it in a lab.
“Plant scientists cannot sit idly by. We are attempting to multiply some plants in the laboratory and then transplant them to our experimental sites in Tibet,” says He. “After five years of continuous observation, it has been found that some transplanted plants can survive and thrive, which may be the dawn of the recovery or at least a postponement of extinction of Takakia populations.”
“People have a responsibility to play a more active role in biodiversity conservation and restoration,” says Hu. “We need to not only focus on those charming animals such as the panda, polar bear, and the white dolphin, but also pay close attention to these rare and little species. They are more vulnerable under climate change, such as our moss Takakia.”
“We humans like to think that we are on top of evolution,” adds Reski. “But the dinosaurs came and went, and so might humans, if we are not careful with our planet. Takakia may die because of climate change, but the other mosses will survive, even if we humans cannot. You can learn a lot from the simplest plants about the history of this planet, and maybe the future.”
