Potatoes evolved from tomatoes and another South American plant 9 million years ago, study finds
The random coupling between wild tomato plants and species similar to potatoes 8 million years ago can have given birth to one of our favorite carbohydrates: the potato.
With 107 existing species and wild potatoes, the cultivated potatoes that we know today (Solanum Tuberosum) belong to the Petota line. New research suggests that this line, or group of closely related species, has emerged from burial between the ancestors of two other lines: tomatoes, which consists of 17 living species, including essential salad Solanum Lycopersicumand Etuberosum, which has three living species from South America.
“From an evolutionary perspective, we had a non-resolution [disagreement] In relations between the tomato, Petota and Etuberosum lines, ” Sandra KnappA research botanist at the Natural History Museum in London and co-author of the new study, told Live Science in an email.
The importance of the unusual in this case, said Knapp, is that it has created new combinations of genes in the Petota line, giving birth to tubers – the inflamed and underground organs that store water and nutrients, which humans eat. The ancestors of modern tomato and study plants had no tubers, and these structures had not appeared in any of the lines because they maintained themselves to produce a hybrid.
“Our results show how an event of hybridization between species can trigger the evolution of new features, allowing even more species to emerge”, co-author of the study Sanwen HuangProfessor of agricultural genomic at the Chinese Academy of Agricultural Sciences, said in a statement. “We finally resolved the mystery of the origin of the potatoes.”
The researchers analyzed the genomes of 128 Petota, tomato and Etuberosum plants to resolve the evolutionary relationships between these lines. They used advanced genomic tools that were not previously available, explaining why scientists had not obtained these results before, Knapp said. The team published its conclusions Thursday, July 31, in the newspaper Cell.
In relation: 2 plants coupled at random 1 million years ago to give birth to one of the most popular drinks in the world
The analysis revealed genetic models “similar to mosaic” in Petota which represented a uniform mixture of DNA inherited from tomato and etuberosum, dating from the origin of potatoes to a crossing event between the two lines between 8 million and 9 million years, wrote the researchers in the study.
An old hybridization event between Etuberosum and tomato is possible because these lines share a last common ancestor between 13 million and 14 million years, according to the study. Despite the independent evolution after the disappearance of this common ancestor, studying the tomato plants can still have in common genetically enough to undertake 5 million years later.
Potato plants resulting from this match produced tubers, which the researchers have linked to several genes. In particular, the team identified SP6A, a gene from the line of tomatoes but has evolved into potatoes to provide instructions on the moment of making tubers. The researchers also highlighted the IT1 gene as involved in the formation of tubers, but this gene came on the side of Etuberosum, according to the study.
The tubers helped potato plants conquer a new soil at a time when the The Andes were underway Rapid signing, suggest the researchers. The unusual “led to a reshuffle of the genes so that the new line produced tubers, allowing these plants to develop in cold and dry habitats in the mountain range Rising Andes,” said Knapp.
The capacity of potato plants to store nutrients and water probably helped them to survive in more severe environments than Etuberosum and tomatoes. This has not only favored the geographic expansion of potatoes, but it also prevented coupling with studying and tomato plants, allowing Petota to evolve into a completely new line, depending on the study.
“The evolution of a tuber has given potatoes an enormous advantage in severe environments, fueling an explosion of new species and contributing to the rich diversity of potatoes that we see and that we are counting today,” said Huang.
