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J Chem Ecol

Title:		Rapidly induced chemical defenses in maize stems and their effects on short-term growth of Ostrinia nubilalis
Author(s):		Dafoe NJ; Huffaker A; Vaughan MM; Duehl AJ; Teal PE; Schmelz EA;
Address:		"Center of Medical, Agricultural, and Veterinary Entomology, USDA and Agricultural Research Service, Gainesville, FL 32608, USA. nicole.dafoe@ars.usda.gov"
Journal Title:		J Chem Ecol
Year:		2011
Volume:		20110811
Issue:		9
Page Number:		984 - 991
DOI:		10.1007/s10886-011-0002-9
ISSN/ISBN:		1573-1561 (Electronic) 0098-0331 (Linking)
Abstract:		"Plants damaged by insect herbivory often respond by inducing a suite of defenses that can negatively affect an insect's growth and fecundity. Ostrinia nubilalis (European corn borer, ECB) is one of the most devastating insect pests of maize, and in the current study, we examined the early biochemical changes that occur in maize stems in response to ECB herbivory and how these rapidly induced defenses influence the growth of ECB. We measured the quantities of known maize defense compounds, benzoxazinoids and the kauralexin class of diterpenoid phytoalexins. ECB herbivory resulted in decreased levels of the benzoxazinoid, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one)-beta-D-glucopyranose (DIMBOA-Glc), and a corresponding increase in 2-(2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one)-beta-D-glucopyranose (HDMBOA-Glc). Total quantities of benzoxazinoids and kauralexins were increased as early as 24 h after the initiation of ECB feeding. The plant hormones, jasmonic acid (JA) and ethylene (ET), and the transcripts encoding their key biosynthetic enzymes also accumulated in response to ECB herbivory, consistent with a role in defense regulation. The combined pharmacological application of JA and the ET precursor, 1-aminocyclopropane-1-carboxylic acid to stem internode tissue likewise resulted in changes in benzoxazinoids similar to that observed with ECB damage. Despite the fact that maize actively mounts a defense response to ECB stem feeding, no differences in percent weight gain were observed between ECB larvae that fed upon non-wounded control tissues compared to tissues obtained from plants previously subjected to 24 h ECB stem herbivory. These rapid defense responses in maize stems do not appear to negatively impact ECB growth, thus suggesting that ECB have adapted to these induced biochemical changes"
Keywords:		Animals Benzoxazines/metabolism Cyclopentanes/metabolism Ethylenes/metabolism Herbivory *Host-Parasite Interactions Inflammation Mediators/metabolism Lepidoptera/*physiology Oxylipins/metabolism Plant Stems/metabolism/parasitology Zea mays/metabolism/*par;
Notes:		"MedlineDafoe, Nicole J Huffaker, Alisa Vaughan, Martha M Duehl, Adrian J Teal, Peter E Schmelz, Eric A eng 2011/08/13 J Chem Ecol. 2011 Sep; 37(9):984-91. doi: 10.1007/s10886-011-0002-9. Epub 2011 Aug 11"