What Put The Heat in Chili Peppers? (broadcast Friday, August 15th, 2008)

Two hemipteran bugs attack the ripened fruit of a chili plant, and scars from previous attacks are visible. Such attacks leave the fruit open to a fungal infestation that can kill the plant's seeds. Image by Tomas Carlo.

New research indicates that chili pepper plants may have developed their signature heat as a way to fight off fungal infections caused by insects. When insects bite into the flesh of a chili pepper, it provides an entry point for a microbial fungus known as Fusarium that can destroy the pepper plant's seeds. Capsaicinoid chemicals produced by the pepper plant inhibit the growth of the fungus -- and it's those chemical compounds that also give chili peppers their spicy kick. In this segment, Ira talks with one of the researchers on the study about the work and what it means for lovers of fiery foods. Teachers, find more information about using Science Friday as a classroom resource in the Kids' Connection.