Submitted to: ACS Symposium Series
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2018
Publication Date: 8/28/2018
Citation: Christensen, S.A., Hunter III, C.T., Block, A.K. 2018. Pesticides on the inside: Exploiting the natural chemical defenses of maize against insect and microbial pests. ACS Symposium Series. https://doi.org/10.1021/bk-2018-1294.ch006.
DOI: https://doi.org/10.1021/bk-2018-1294.ch006

Interpretive Summary: Corn (maize, Zea mays) is one of the most significant and abundantly grown crop plants in the United States with yields exceeding $50 billion annually. Despite major improvements in productivity, it is estimated that billions of bushels are lost per year due to the combined damage of insects and disease. The use of insecticides and fungicides has been a long-standing strategy to manage these pests; however, the broad public recognition of the environmental and human-health concerns associated with synthetic pesticides has heightened interest in the use of genetic tools to provide immunity. Breeding programs continue to work towards optimizing maize lines for effective resistance; however, the lack of knowledge of the molecular mechanisms and specific defense chemicals that regulate pest resistance limits rapid progress in this area. Scientists at the USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology in Gainesville, FL are addressing this critical issue by identifying and/or characterizing important maize plant-produced defense chemicals. Detailed molecular knowledge of plant defense is critical for improving the agro-economic stature of US and global crop production. In this chapter, we highlight current knowledge regarding maize defense chemistry and discuss future strategies to exploit it for enhanced resilience to biological threats.

Technical Abstract: Maize (Zea mays) is one of the most significant and abundantly grown crop plants in the United States with yields exceeding $50 billion annually. Despite major improvements in productivity, it is estimated that billions of bushels are lost per year due to the combined effects of herbivory and disease. The use of insecticides/fungicides has been a long-standing strategy to manage pests; however, the broad public recognition of the environmental and human-health concerns associated with synthetic pesticides has heightened interest in the use of genetic tools to provide immunity. Breeding programs continue to work towards optimizing maize lines for effective resistance; however, the lack of knowledge of the molecular mechanisms and specific defense chemicals that regulate pest resistance limits rapid progress in this area. To address this critical issue, efforts have been made to elucidate and characterize important maize defense chemicals including benzoxazinoids, terpenoid phytoalexins, free fatty acids, hormones, inducible volatiles, and flavonoids. In this chapter, we review the existing knowledge of these maize defense chemicals and discuss current and future strategies to exploit them for enhanced resilience to biological threats.