New genetic research on flowering plants changes the tree of life at a large scale

Botanists have used genome data from more than 9,500 species to map evolutionary relationships among flowering plants. The newly compiled Tree of Life will help scientists piece together the origins of flowering plants and inform future conservation efforts.

Approximately 90 percent of plants that live on land are flowering and fruiting plants called angiosperms. These flowering plants are essential to maintaining Earth's ecosystems, including storing carbon and producing oxygen, and they make up a large portion of our diet.

“Our very existence depends on them,” he says. william baker At the Royal Botanic Gardens in Kew, England. “That's why we need to really understand them.”

For the past eight years, Baker and his colleagues have been working to complete the Tree of Life, which describes the evolutionary relationships between all genera of plants and fungi.

Starting with flowering plants, the researchers designed molecular probes to search for 353 specific genes found in the nucleus of all angiosperms. “The nuclear genome is huge,” Baker says. “So we needed to focus on a specific set of genes.”

Researchers have so far sequenced the genes of 9,506 species of flowering plants, primarily using specimens from collections and public databases around the world. This represents nearly all known angiosperm families and approximately 8,000 of the 13,400 recorded genera.Some of the specimens collected in the analysis are more than 200 years old; Arenaria globifloraand many Guadalupe Island olives (Espererea Palmeri).

By comparing the similarities in the gene sequences of different flowering plants, researchers were able to figure out where they fit on the tree of life.

Baker says this is the most comprehensive survey of angiosperms to date. “We often liken it to the periodic table of elements,” he says. “It's the basic framework for life.”

Angiosperms emerged about 140 million years ago and have rapidly flourished, overtaking flowerless gymnosperms to become the world's dominant plant species. The sudden appearance of the diversity of flowering plants in the fossil record has baffled scientists for the past few centuries, and Charles Darwin called it “a hideous mystery.”

Now, the Tree of Life confirms that about 80 percent of the major flowering plant lineages that still exist today were part of this early boom in angiosperm diversity. “We can't say we've solved this 'damn mystery,' but at least we can say it really does exist,” Baker said.

The tree of life also highlights a further surge in diversity that occurred around 40 million years ago, possibly caused by a drop in global temperatures at the time.

In the future, he says, the Tree of Life could also help in the search for plants with pharmaceutical properties for new drugs. Ilia Leech, another member of Cue's team. It also helps scientists identify new species and assess which species are most vulnerable to climate change.

“This is the latest and greatest evolutionary framework for conducting new research that approaches the mechanisms that have allowed flowering plants to take over the world,” he says. ryan falk at Mississippi State University.