Researchers Reveal Characteristics of Plant Defense Compound Dhurrin

An international research team has identified the mechanism by which sorghum uses the compound dhurrin to ward off pests and herbivores. Previous studies have found that sorghum releases chemicals when attacked by pests, or plant eaters. Dhurrin is one such chemical, which turns into cyanide when hydrolyzed. It is classified as one of a type of complexes known as metabolons — temporary complexes formed between enzymes in a metabolic pathway. In their research, the researchers learned more about the general nature of such complexes by studying what happens when sorghum plants are attacked.

The team isolated dhurrin samples from endoplasmic reticulum using a recently developed technique. They identified four of the players involved in converting an amino acid to dhurrin. One of them was a protein that served as an electron donor; two others were proteins that triggered the process, and the fourth was an enzyme that helped the other transactions take place. They noted that all four proteins performed in concert to convert an amino acid called L-tyrosine to dhurrin, and found that the membrane itself was a critical part of the metabolon character.

For more details, read the paper in Science.