Dandelion Latex Protects Roots from Feeding Insects

Dandelions are weeds disliked by many gardeners, but these plants have many insect enemies because of their bitter-tasting latex. Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, and the University of Bern, Switzerland, have demonstrated that a single compound in the latex protects dandelion roots against voracious cockchafer larvae.

The scientists found the highest concentrations of the bitter latex in the roots of dandelions. An analysis of the components of dandelion latex revealed that a single substance identified as the sesquiterpene lactone, taraxinic acid β-D-glucopyranosyl ester (TA-G), negatively influenced the growth of cockchafer larvae. When the purified substance was added to an artificial larval diet in ecologically relevant amounts, the grubs fed considerably less.

The researchers succeeded in identifying the enzyme and gene responsible for the formation of a precursor of TA-G biosynthesis, and were able to engineer plants with lower TA-G. Roots of engineered plants with less TA-G were attacked more by cockchafer larvae. A common garden experiment with different dandelion lines revealed that plants which produce higher amounts of TA-G maintained a higher vegetative and reproductive fitness when they were attacked by cockchafer larvae.

For more details about this research, read the news release at the Max Planck Institute for Chemical Ecology.