Organism who have the last laugh against Defensive Plants

Article: Playing tag with sugars in the cornfield

Date Published: September 25, 2014 

            Sugar plays a big role as an energy source for plants as well as for insects. Sometimes plants develop “special powers” by that I mean they have defense mechanisms that allow them to replace the sugar with an active toxin when an organism is feeding on them. Therefore, the organism will soon decease from this toxin and the plant will survive. But sometimes this special power does not work on certain organisms such as the Spodoptera larvae. Researchers such as the Max Planck scientist have gained interested when they discovered massive crop damage to the plants as well as discovered that the toxin with the sugar is still attached. Scientist found that the insect reattaches the removed sugar to the opposite stereochemical configuration. Placing the removed sugar in the opposite configuration is a way to detoxify the defensive plant. Over the years insects such as the Spodoptera larvae in a way have conquered plant defenses by developing ways to detoxify harsh substances from plants.

            Throughout the world there is an enormous amount of crops which has insect pests that have grown to adjust to these defensive plants. Researchers from the Department of Biochemistry at the Max Planck Institute found out the tactic of the pest insects. The pest insects unfold a gut enzyme that catalyzes the attachment of a sugar to the toxic free sugar group called DIMBOA. Once the sugar group is attached in a different position which is the mirror-image orientation, forming a (2S)-DIMBOA-glucoside this causes the plant to not remove it a second time. Having a different sugar orientation causes the plant to be non-toxic and thus the (2R)-DIMBOA-glucoside cannot be formed anymore. In the figure below, shows an illustration of (2R)-DIMBOA-glucoside and (2S)-DIMBOA-glucoside which clearly demonstrates same molecules but since it is a mirror image they have an entirely different mode of action. 

Overall, the Spodoptera larvae is having the last laugh against the defensive plant until the plant develops a new way of fighting of these pesky insects. 

References and Pictures:

https://www.ice.mpg.de/ext/1166.html