One of the most complete sets of known plant genome to date has just been published: the carrot. The complete sequence sheds light on the evolutionary origin of this vegetable, its distinctive orange color and nutritional value.
US – Carrots belong to the phylogenetic tree of other plants such as celery, lettuce and sunflower. However, the genomes of these crops, important in human diets around the world, had not yet been published, until today.
A new study led by the University of Wisconsin-Madison (USA) described in the journal Nature Genetics the genome sequencing of carrot.
“The immediate users of the entire genome sequence will plant breeders, who will use it for marker-assisted selection for resistance to diseases of seeds and to learn more about the characteristics of the crop. Will also be useful for several laboratories conducting fundamental research on carrot pigments, their response to biotic and abiotic stresses, growth, reproduction and evolution,” Philipp Simon, a researcher at the University of Wisconsin-Madison and co-author of the study, told SINC.
The researchers compared the sequence of carrot with other plant genomes and determined when the divergence occurred in the evolution of these vegetables. Carrot was separated from the grape 113 million years, Kiwi 101 million years ago, and potato and tomato makes 90.5 million years ago. “With the publication of the genome sequence of carrot, the evolution of this group of plants is best understood,” said Simon.
According to the scientist, “the genome contributes to our understanding of the biosynthetic pathways of other features carrot, including genes that influence the accumulation of carotenoids, anthocyanins, carbohydrates and terpenoids. It will also expand knowledge on pest and disease resistance, abiotic stress responses, reproduction and growth; and will help produce more efficient crops.”
Greater genetic variety that humans
Scientists know that fruits and vegetables are not only a source of calories and fiber, but also provide numerous vitamins and other compounds that have a beneficial effect on health. “Advances in sequencing technologies give scientists new information plant to develop crop varieties with higher nutritional value,” adds the researcher.
The number of genes in the genome of carrot (32,113) is typical for plants, of around 30,000 on average. “Interestingly plant genomes on average contain more genes than the human genome. This is probably because many plant genomes have doubled over the course of its evolution,” argues Simon.
To date, more than 100 have been sequenced genomes of plants, including about 11 crops of vegetables including potato, tomato, cucumber and peppers.
A gene responsible orange
The study authors found a responsible high accumulation of beta-carotene, a precursor of vitamin A, in the root of the carrot gene. “The gene described realizes capacity carrot roots to accumulate carotenoid pigments and is one of the two genes responsible for the conversion of white carrots (ancestral wild type) to orange.”
Without it, carrot roots may be white (no pigment carotenoid), or pale orange (with low amounts of beta-carotene). Based on historical records they have been able to discover how dark orange carrots (with high amounts of beta-carotene) first entered the vegetable market by the year 1500. “Both the gene mutation is needed and, as Y2 gene mutation that carrots have high amounts of beta-carotene, ” concluded Simon.