Most supermarket tomatoes have been bred to travel. In other words, they possess a mutation in a ripening gene that leads to slower fruit softening, thereby allowing the popular produce to be shipped around the world without getting squished. Unfortunately for consumers, that ripening gene also directs flavour and colour production. Its mutation blocks these tomatoes from ever fully ripening, leaving consumers with a relatively bland incarnation of the fruit. But theres hope for tomato lovers, courtesy of a team led by the University of Nottinghams Graham B. Seymour. The researchers identified a gene coding for a pectin lyase enzyme that starts the softening process by breaking down complex polysaccharides in tomatoes. Using RNA interference, they silenced this gene in a flavourful variety of tomato called Ailsa Craig, which is commonly grown by gardeners but is too soft to be shipped the global distances required by the tomato industry. The team found that the transgenic tomatoes did not activate the softening chain reaction, leading to fruits that were travel hardy with no consequences to flavour and colour (Nat. Biotechnol. 2016, DOI: 10.1038/nbt.3602). Given the publics concern about genetically modified organisms, the discovery is unlikely to result in transgenic tomato crops. But the work could guide scientists to use conventional breeding strategies to grow pectin lyase mutant varieties.
Chemical & Engineering News, 1 August 2016 ;http://pubs.acs.org/cen/news ;