Scientists have deciphered the full genome of resilient potatoes: has hybrid origins and six sets of chromosomes, three times more than humans.
Sweet potato looks like a simple food, but a team of researchers has just discovered that food is one of the most genetically intricate agricultural crops ever studied.
According to a study in August at Nature Plants, the full genome of sweet potatoes was deciphered and revealed that this is a hybrid species with Six full sets of chromosomes – Three times more than humans.
The complexity of the sweet potato genome has actually difficult for efforts to improve the plant, through intersections or genetic engineering, note. Unlike other crops such as wheat – where ancestral genetic contributions are organized in different sections of genome – the genetic composition of the essential potatoes in various parts of the world is one as an intertwined mosaic.
Sweet potatoes is extremely resistant, requires few pesticides and produces about 70 kilocalories per hectare per day, which makes it one of the base crops more efficient to cultivate. So resolving this puzzle has been a priority of Cornell’s team.
To this end, the team resorted to advanced DNA sequencing techniques to map the Tanzania variety genome, known for the high productivity and disease resistance. It was able to separate the 90 chromosomes from the plant into six distinct sets, called haplotypes, reaching an unprecedented level of detail. “It allows us to read the genetic history of sweet potatoes with an extraordinary detail,” said the main investigator Zhangjun Fei.
The study reveals that sweet potato is a segmental alopolipoliploid-a hybrid resulting from several ancestral species which, genetically, behaves as if it originated in one. This complex structure may be at the basis of its remarkable resilience, as the six sets of chromosomes provide several copies of essential genes, a phenomenon known as polyploid damping. These reserve copies help the plant resist drought, combat pests and adapt to different environments.
With this genetic map now available, scientists expect to identify genes linked to performance, nutritional value and disease resistance, paving the way to future improvements of the already powerful potato. Developed methods may also help unravel other complex crops, such as wheat, cotton and bananas, unlocking new agricultural advances worldwide.
