Why Are Conventional Tomatoes So Tasteless? Because They’re Red!

published Jul 2, 2012

Why are some tomatoes so tasteless? It’s due to disregarded seasonality, yes, and long, chilled shipments (both of which destroy flavor), but plant geneticists have discovered an imbedded source: the gene mutation that makes tomatoes bright red, and which was deliberately bred into tomatoes by plant breeders, is now known to to stifle the gene that makes tomatoes tasty! So red tomatoes = tasteless tomatoes. Who knew?

The study, recently published in the journal Science, reports that the gene inactivated by the make-it-red mutation is actually the one responsible for providing the sugars and sweet smells that accompany the best tomatoes. Ann Powell, a plant biochemist at the University of California, Davis and the lead author of the Science paper, put weed genes into tomato plants, and was surprised when the tomatoes with the genes turned dark green right before ripening, rather than the pale green of most tomatoes. The green color comes from chloroplasts, the “factories” in plant cells where photosynthesis takes place and converts light into sugar which the plant uses use for food. The weed gene, she discovered, was effectively replacing a disabled gene in a tomato’s fruit, and turning it dark green.

The researchers used genetic engineering to turn on the disabled genes while leaving the uniform ripening trait alone. The fruit was evenly dark green and then red and had 20 percent more sugar and 20 to 30 percent more carotenoids when ripe.

Of course, since this was a science experiment, the scientists were unable to actually taste the tomatoes. However, the higher sugar content seems to suggest better flavor. But even if this is true, don’t expect to see genetically engineered tomatoes on store shelves anytime soon. (Producers would never make it for fear of alienating customers.) The workaround? Heirloom and wild specie tomatoes that have not been bred with the uniform ripening mutation. So that’s why they taste so much better!

(Image: S. Zhong and J. Giovannoni via The New York Times)