How did the tomato create the potato? Chinese scientists trace tuber’s hybrid past
Researchers conduct ‘DNA paternity test’ on potato varieties in ‘pioneering’ study that sheds light on ancient origins of the staple crop
All varieties of potato have underground tubers, but until now it has not been clear how they developed them and diversified.
The potato is the third most widely consumed food crop globally, after rice and wheat, and is eaten by over 1 billion people, according to the United Nations Food and Agriculture Organization.
Zhang Zhiyang, the study’s first author and a researcher at the Agricultural Genomics Institute at Shenzhen under the Chinese Academy of Agricultural Sciences, said that the question of the origin of the potatoes had not been resolved.
“Wild potatoes are a huge treasure trove of resources, but little research has been done on them,” Zhang was quoted as saying by the state-run China Science Daily.
The study was led by Huang Sanwen, also a researcher at the same genomics institute, in collaboration with scientists from Canada, Germany, the United States and Britain.
In 2022, an accidental discovery by Zhang in the field of potato gene research inspired his mentor, Huang, who thought it might be evidence of the potato’s hybrid origin, according to the report.
The team conducted what they described as a “DNA paternity test” on all potato varieties and concluded that tomato plants accounted for about 40 per cent of their genes and the potato-like etuberosum made up the rest.
“There are 107 wild potato species, and collecting samples is extremely challenging. Our work has yielded the most comprehensive collection of wild potato genomic data to date,” Zhang was quoted as saying.
Much of the potato’s success comes from its tubers.
Around the time the hybrid emerged, the Andes Mountains in South America were rising rapidly, resulting in environmental changes.
Tubers enable plants to store water and starch and, according to the researchers, this helps potatoes adapt better to dramatic environmental changes.
Tubers also helped potatoes reproduce without seeds or pollination, Zhang was quoted as saying.
“The highest diversity of wild species of [potato] is found in high-elevation, cold-adapted montane habitats in central Mexico and the central Andes,” the team said in their paper, referring to mountainous eco-systems.
“Species of [potato] have a much wider geographical distribution and tend to occupy a broader range of environmental conditions than species of either tomato or etuberosum.”
Loren Rieseberg, the study’s co-corresponding author and a professor of botany and biodiversity at the University of British Columbia in Canada, told China Science Daily that the study was “the most exciting and compelling report to date” on the significance of ancient hybridisation for plant diversity.
The newspaper quoted James Mallet, a professor of evolutionary biology at Harvard University, as saying that the study was “pioneering”.
“It demonstrates how hybridisation events can trigger the emergence of new organs and even lead to the emergence of new species,” Mallet said.
Study lead Huang told China Science Daily that the work would provide new theoretical insights for the genetic breeding of future hybrid potatoes. “Tomatoes might not only be part of the potato’s past, but also its future,” he said.