D3394: Nine thousand years apart: Examining how production of herbivore-induced plant volatiles has shifted over maize domestication history

Domestication of plants for agriculture and directed breeding has strongly affected plant-insect interactions. Modern maize was domesticated from its wild ancestors approximately 9000 years ago. The transition from wild teosinte and locally adapted landrace varieties to modern varieties has changed the genetic and morphological architecture of maize. These changes may have altered plant defense mechanisms including herbivore-induced plant volatiles (HIPVs), that mediate critical ecological interactions among plants, insects, and their natural enemies. To date, our understanding of how production and emission of volatiles following insect herbivory has changed through domestication and crop improvement remains limited. Moreover, the few available studies have produced inconsistent patterns. This study was conducted to investigate whether maize domestication has altered the total and overall composition of HIPVs. We used 24 maize genotypes that were selected to cover major events in maize domestication history. Maize plants were grown under greenhouse conditions for 4 weeks. Plants were subjected to damage by the fall armyworm Spodoptera frugiperda larvae followed by collection of herbivore-induced volatiles. Volatiles were analyzed and identified using gas chromatography-mass spectrometry. Our results showed that maize domestication history influenced total amounts of herbivore-induced plant volatiles. In addition, we documented differences among the 24 genotypes in the relative amounts of particular compounds within the total HIPV blend. To fully exploit VOC signals to improve maize plant anti-herbivore defense, it is necessary to develop a thorough understanding of how domestication and crop breeding has inadvertently altered induced volatiles emission following insect herbivory.