
Despite its toxicity in plants at higher levels, crops supply most of the essential dietary selenium in humans. Selenium toxicity in plants has been attributed to the formation of non-specific selenoproteins; however, this paradigm can be challenged now that there is increasingly abundant evidence suggesting that selenium-induced oxidative stress also contributes to toxicity in plants. Van Hoewyk provides an updated framework on plant selenium toxicity by indicating that both malformed selenoproteins and oxidative stress drive selenium-induced stress. Although challenging, distinguishing between these two distinct types of stress may be useful in the future development of crops with fortified levels of selenium.