‘Hidden mutations’ in the genetic makeup of tomato plants can be used to create bigger, tastier ‘super varieties’, study claims
- More than 200,000 genetic mutations were identified in 100 tomato varieties
- When one plant had its DNA mutated it produced 30 per cent larger tomatoes
- Scientists hope the findings could lead to larger yields for farmers in the future
‘Hidden mutations’ in the DNA of tomato plants could boost their size, weight and flavour leading to new ‘super varieties’, a study has claimed.
Scientists analysed the genomes of 100 tomato varieties, including an orange-berried tomato that grows on the Galapagos and the type used in Ketchup, to reveal more than 200,000 genetic mutations.
The team then used this newfound knowledge to modify a plant’s genome, causing it to produce 30 per cent larger tomatoes.
The research could help boost yields for British farmers and reduce reliance on imports, as the UK currently has to buy 80 per cent of its tomatoes overseas.
Scientists identified 200,000 mutations in 100 varieties including an orange-berried one that grows in the Galapagos, and those used to make ketchup and sauces
Scientists studying genetic mutations in plants and animals have generally focused on smaller mutations, in which one DNA letter is swapped out for another.
However, for this study, the research team used a technique called long-read sequencing to identify much larger structural variations in over 100 types of tomato.
‘It is like looking through a panoramic window at large sections of the genome,’ said Dr Zachary Lippman from Howard Hughes Medical Institute in the US, who co-authored the study.
‘By comparison, more conventional sequencing offered only a peephole.’
Using this technique to copy, delete and move long sections of DNA to other parts of the plant’s genome, the team were able to identify over 200,000 structural variations.
‘What’s clear is that many of these mutations alter mechanisms controlling genetic activity,’ Dr Lippman said.
‘Plants lacking the gene never made fruit, while plants with three copies of the gene made fruit about 30 per cent larger than those with just a single copy.’
When the researchers used their newfound knowledge to mutate a tomato plant, it produced 30 per cent larger tomatoes
The discovery could help farmers improve their yields from tomato crops.
Dr Lippman added: ‘These sorts of insights could help explain trait diversity in other crops and enable breeders to improve varieities.
‘For instance, perhaps adding an extra copy of the size gene to tiny ground cherries, a close relative of tomato, could increase their appeal by making them larger.
‘One of the holy grails in agriculture is to be able to say, “if I mutate this gene, I know what the output will be”.
‘The field is making important steps toward this kind of predictable breeding.’
The findings were published in the journal Cell.
What is the origin of tomato plants?
Tomato plants were first domesticated in South America thousands of years ago
Short-lived small plants producing larger red berries would never have evolved without the help of humans.
The world’s highest value crop is thought to have first been domesticated in South America from the wild plant, Solanum lycopersicum cerasiforme, which produced tomatoes about the size of a blue berry.
Farmers then only allowed their crops producing larger berries to breed, gradually increasing the size of the tomato.
However, as these crops were taken northwards they began losing fruit size and taste.
This resulted in a second hybridisation event about 7,000 years ago in Ecuador, Mexico and other areas in central America, where wild weed-like S. lycopersocum cerasiforme tomatoes were interbred with their domesticated cousins to re-invigorate the crops.
This produced the common tomato, which was taken around the world after Europeans arrived in the Americas in the 16th century.
They are believed to have been taken to Europe either by Spanish conquistadors or two Jesuit priests who were returning to Italy.
Source: Journal of Molecular Biology and Evolution, April 2020