A maize landrace that emits defense volatiles in response to herbivore eggs possesses a strongly inducible terpene synthase gene

Abstract

Plants with the ability to produce higher levels of defence volatiles significantly reduce damage inflicted by harmful pests, by recruiting natural enemies of the pests: Once an insect feeds on or deposits eggs on a maize plant, it emits chemicals—called herbivore-induced plant volatiles—to protect it. The volatiles prevent the insect from feeding on the maize plant and attract the insect’s natural enemies to it. The volatiles also warn adjacent plants of the attack. Maize varieties differ in their ability to produce the signal. Furthermore, only certain maize cultivars respond at the egg-laying stage of pest attack. This article provides the first molecular evidence on a defence trait expressed by a maize landrace in response to both insect egg deposition and feeding. This finding opens up the prospect of incorporating the traits into elite maize varieties, to protect crops against damaging insect pests. This is an output from the ‘Smart Cereals for Management of Stemborer Pests in Staple Cereals in Africa’ project. It was partly funded by the UK Department for International Development, a core donor of the International Centre of Insect Physiology and Ecology