Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Biological Chemistry

Bitterness in wild cucumber, melon, and watermelon

Researchers track down biosynthetic genes responsible for the unpalatable flavors and how human domestication eliminated them

by Sarah Everts
December 5, 2016 | A version of this story appeared in Volume 94, Issue 48

[+]Enlarge
Credit: Shutterstock

In the wild, watermelons (shown), cucumbers, and muskmelons produce bitter cucurbitacins to defend against predators.
Image of cucumbers, muskmelons and water melons.
Credit: Shutterstock

In the wild, watermelons (shown), cucumbers, and muskmelons produce bitter cucurbitacins to defend against predators.

When cucumbers, muskmelons, and watermelons grow in the wild, their fruit contains bitter cucurbitacin molecules, a family of highly oxygenated tetracyclic triterpenes that deter pests from foraging. Although these defense compounds evolved in the plants millions of years ago, humans have bred them out of the fruits to make them more appealing to our palate. A team of researchers led by Yi Shang and Sanwen Huang of the Chinese Academy of Agricultural Sciences has examined the biosynthetic pathways responsible for cucurbitacins, which are also being investigated as anticancer, anti-inflammatory, and laxative agents. They find that human domestication has successfully interfered in the gene expression of important enzymes in the cucurbitacin pathways in the fruit (Nat. Plants 2016, DOI: 10.1038/nplants.2016.183). In watermelon, for example, a single point mutation in a transcription factor results in a dysfunctional protein and reduced bitter compounds in domesticated varieties of the fruits. Interestingly, cucumber, melon, and watermelon plants continue to make the defensive compounds in other parts of the plant, such as roots, leaves, and stems, using other transcription factors: It’s a useful workaround to satisfy their human masters, while maintaining some armor.

Structures of various cucurbitacins.

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.