A group of plant scientists from Cornell University in the United States has discovered a gene that could increase the odds that future store-bought tomatoes stay firm until the consumer gets them home and have the right combination of flavour and softness when eaten.
The study delved into the genome of the tomato (Solanum lycopersicum) and identified a transcription factor (SlLOB1), that regulated a broad array of cell wall-related genes and fruit-softening processes.
“SlLOB1 is interesting because it primarily regulates genes involved in cell wall softening and other textural changes of the fruit,” explained Jim Giovannoni who led the work. Modulating SlLOB1 could yield ripe, and therefore flavourful, tomatoes that haven’t begun to soften, increasing their shelf life.
In live tomato plants, the team found that inhibiting expression of SlLOB1 resulted in delayed softening and firmer fruit, whereas overexpression of the gene accelerated the softening process. Importantly, the team showed that inhibiting SlLOB1 expression had no effect on the ripening process: the tomatoes ripened in their normal time frames. Fruit levels of sugars and acids were unaltered, suggesting that “from a flavour perspective, the fruits were likely unchanged,” said Giovannoni, though he acknowledged the study did not include taste tests. “What did change is the texture of the fruits; they remained firmer longer and softened later.”
“If we can find SlLOB1 gene variants that delay softening, breeders could introduce those into commercial varieties to produce high-quality, good-tasting tomatoes that don’t become too soft before the consumer gets them home,” he said. “These tomatoes also have an increased nutritional quality because these pigments are antioxidants, and your body converts beta-carotene to vitamin A.”