An international team of researchers has mapped and analyzed the genome of the liverwort Marchantia polymorpha, a species of land plant found around the human habitat in temperate regions. The findings are published in the journal Cell.
Starting with Greek philosophers such as Aristotle and Theophrastus, this species had been mentioned in the herbal literature — in many cases as ‘lichen’ — long before modern plant taxonomic study was applied.
In the Middle Ages in Europe, Marchantia polymorpha was thought to be useful for treating diseases of the liver on the basis of the doctrine of signatures, by which a plant resembling a human organ was thought to be useful in treating diseases of that organ.
In the 19th century, the species was already one of the most studied species in plant science.
“All land plants, from moss on rocks to trees that flower, evolved from a common ancestral algal species that colonized land about 500 million years ago,” said co-lead author Dr. Takayuki Kohchi, of Kyoto University, Japan.
“The liverwort diverged from other land plants at the earliest stage of evolution, and therefore still possess ancestral characteristics of plant species that followed.”
Dr. Kohchi and colleagues identified 19,138 genes in the genome of Marchantia polymorpha, discovering in part the low level of genetic redundancy that controls the plant’s development and physiology.
“Flowering plants have redundant copies of vital genes in their DNA, so that if something goes wrong, there’s a backup,” Dr. Kohchi said.
“And while liverworts have the fundamental ancestral versions of basic mechanisms to keep plants alive, these are exceedingly simple.”
“Based on these findings, the scientific significance of the lowly liverwort is now unassailable,” the researchers said.
“It is a key model plant for molecular and genetic studies, providing hints to future agricultural applications and plant breeding technologies.”
“Now that we know the liverwort genome, we can begin to decipher the functions of each individual gene, and how these evolved in later plant species,” Dr. Kohchi said.
John L. Bowman et al. 2017. Insights into Land Plant Evolution Garnered from the Marchantia polymorpha Genome. Cell 171 (2): 287-304; doi: 10.1016/j.cell.2017.09.030