U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Chemistry Research: Gainesville, FL
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Southeast Area Gainesville, Florida Center for Medical, Agricultural and Veterinary Entomology Chemistry Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Schmelz, Ericitem
                                            Kaplan, Fatmaitem
                                            Huffaker, Alisaitem
                                            Dafoe, Nicoleitem
                                            Vaughan, Marthaitem
                                            Ni, Xinzhiitem
                                            ROCCA, JAMES - University Of Floridaitem
                                            Alborn, Hansitem
                                            Teal, Peter
  Submitted to: Meeting Abstract
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 8/7/2011
                                    Publication  Date: N/A
                                    Citation: N/AInterpretive Summary:
                                Technical Abstract: Phytoalexins are pathogen and insect-inducible biochemicals that are deployed to locally inhibit further biotic attack. Due its agronomic significance, maize has been extensively investigated for terpenoid-based defenses including insect-inducible terpene volatiles which function as indirect defenses through the attraction of predators and parasitoids of the offending herbivores. Unlike these low molecular weight volatile terpenes, the role of larger terpenoids in maize defense remains largely unknown. In response to stem attack by the European corn borer (Ostrinia nubilalis) and fungi, we observed the induced accumulation of six ent-kaurane-related diterpenoids, collectively termed kauralexins. Chromatographic isolation and NMR-based identification of the predominant Rhizopus microsporus induced metabolites revealed ent-kaur-19-al-17-oic acid and the novel analog ent-kaur-15-en-19-al-17-oic acid, assigned as kauralexin A3 and B3, respectively. Encoding an ent-copalyl diphosphate synthase, fungal-induced An2 transcript accumulation precedes highly localized kauralexin production which can eventually exceed 100 'g g-1 FW. Pharmacological applications of jasmonic acid and ethylene also synergize the induced accumulation of kauralexins. At concentrations as low as 10 'g ml-1, kauralexin B3 significantly inhibits the growth of the opportunistic necrotroph R. microsporus and the causal agent of anthracnose stalk rot, Colletotrichum graminicola. Kauralexins also exhibit significant O. nubilalis antifeedant activity. Our work establishes the presence of highly-inducible diterpenoid phytoalexin defense responses in maize and enables a more detailed analysis of the associated biosynthetic pathways, regulation and defense functions.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov