Location: Chemistry ResearchTitle: Production and function of terpenoid defense compounds in maize (Zea mays)
Submitted to: Planta
Publication Type: Review Article
Publication Acceptance Date: 8/30/2018
Publication Date: 9/6/2018
Citation: Block, A.K., Vaughan, M.M., Schmelz, E.A., Christensen, S.A. 2018. Production and function of terpenoid defense compounds in maize (Zea mays). Planta. https://doi.org/10.1007/s00425-018-2999-2.
Interpretive Summary: Corn is one of the major global agricultural crops yet its production is limited by pest damage, both from insects and microbial pathogens. Corn has several lines of defense against these attacking organisms, one of which is the use of large class of chemicals called terpinoids. In this article ARS scientists from Gainesville and Peoria review what is known about the terpinoids corn makes to protect itself from pests including the identity of the different compounds and the enzymes that make them. Furthermore we assemble what is known about the function of each compound both in terms of direct toxicity to the pests and also in terms of attracting predatory or parasitic insects to help remove attacking insects.
Technical Abstract: Chemical defenses are used throughout the plant kingdom to protect plants from invaders. In this review we outline what is known about a subset of these defenses (terpenoids) in the agriculturally important crop maize (Zea mays). Maize produces a range of terpenoid defenses including a bouquet of volatile monoterpenes and sesquiterpenes such as ß-myrcene and (E)-ß-caryophyllene as well as non-volatile phytoalexins such as the sesquiterpene zealexins and the labdane-related diterpenoid kauralexins and dolabralexins. These defenses can be effective against both microbial and insect pests via both direct mechanisms such as antimicrobial or anti-feedant activity and indirect mechanisms such as the attraction of predators or parasitoids. The number and promiscuity of terpene synthases, coupled with the variety of secondary modifications possible, provides maize with an arsenal of terpinoid defensive compounds whose identity, production and function are only beginning to be understood.