Plants do not require UV radiation from the sun. In fact, it can cause poor growth or death by damaging plant proteins and DNA. To mitigate the threat, they display a complex response switched on by a UV-sensing protein molecule.
Researchers have identified a compound that can detect the presence of UV-B light and initiate a broad set of defensive actions. This response involves the expression of more than 100 genes, some of which govern activities like the formation of DNA-repair enzymes and other protective proteins. The chemical's principal investigator, Elizabeth Getzoff, called it "the plant equivalent of putting on sunscreen."