Myrosinase: gene family evolution and herbivore defense in Brassicaceae

Glucosinolates are a category of secondary products present primarily in sp ecies of the order Capparales. When tissue is damaged, for example by herbi vory, glucosinolates are degraded in a reaction catalyzed by thioglucosidas es, denoted myrosinases, also present in these species. Thereby, toxic comp ounds such as nitriles, isothiocyanates, epithionitriles and thiocyanates a re released. The glucosinolate-myrosinase system is generally believed to b e part of the plant's defense against insects, and possibly also against pa thogens. In this review, the evolution of the system and its impact on the interaction between plants and insects are discussed. Further, data suggest ing additional functions in the defense against pathogens and in sulfur met abolism are reviewed.