Yesterday saw a flurry of reports about a new article in Science on tomato flavor, or the lack thereof. Here are a few:
- How Tomatoes Lost Their Taste (ScienceNow)
- How The Taste Of Tomatoes Went Bad (And Kept On Going) (The Salt, NPR food blog)
- Not Like They Used to Be – Cardboard Tomatoes (Babbage blog from The Economist)
While it’s great to see such widespread coverage of a plant science discovery, as I read through each report I couldn’t help but notice the disconnect between the bold titles and the substance of each article.
Here is the science: the researchers found the molecular identity of a historical mutation in fruit development that plant breeders have selected for that makes the fruits more uniform in color and lighter green. The gene encodes a transcription factor that controls chloroplast development. When mutated, as in almost all cultivated tomatoes, it leads to fruits with fewer chloroplasts, which explains the lighter, more uniform coloration. It also leads to lower carbohydrate and pigment concentrations, which the researchers suggest could impact flavor.
The problem with the bold article titles is, the flavor of a tomato is much, much more complex than its sugar content. Tomatoes contain over 400 volatile compounds, each of which interacts with the others and nonvolatile compounds to produce the overall flavor profile. Understanding how each of those hundreds of molecules is formed and processed in the fruit throughout ripening is likely to yield better tasting tomatoes, and maybe having more total carbohydrates will be a part of that process. But the original article didn’t even begin to explore flavor, so why is that the take-home message of all the news pieces?
To me, the Science paper is extremely interesting, but not for the reasons highlighted in these articles. This is a case of classical breeding carrying out selection on a trait that seemed to improve the crop, at least from the standpoint of the grower, making it more consistent and easier to market. But now that we know what (in the molecular sense) they were selecting, we can see it was probably a poor tradeoff. This is yet another in a long line of links between classical breeding choices and molecular genetics, and this represents an excellent way to educate the public that all of our food is genetically modified! It all has DNA! Genes, even! I continue to be fascinated as we uncover the ancient — and recent — mutations that produced the foods we know, and I think it provides a great chance to inform and begin a dialog over the nature of farming, breeding, and genetics.
Gravitropic 