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
 Mycotoxin Prevention and Applied Microbiology Research: Peoria, IL
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    NCAUR homepageSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Peoria, Illinois National Center for Agricultural Utilization Research Mycotoxin Prevention and Applied Microbiology 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
- MPM Home Page
- Mission Statement
- Strategic Goals
- Major Accomplishments
- Visiting Scientists

Title:   Author  item
                                            Alexander, Nancyitem
                                            McCormick, Susanitem
                                            Desjardins, Anne
  Submitted to: Meeting Abstract
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 12/4/2008
                                    Publication  Date: 12/4/2008
                                    Citation: Alexander, N.J., Mccormick, S.P., Desjardins, A.E. 2008. Virulence of Gibberella zeae on Wheat following Independent Disruptions of Trichothecene Biosynthetic Genes [abstract]. Proceedings of the 2008 National Fusarium Head Blight Forum. Poster No. 52. p. 79.Interpretive Summary:
                                Technical Abstract: The plant-fungal interaction that occurs when Fusarium graminearum invades small grains such as wheat and barley is complicated and involves many interactions between the invading fungus and the plant host.  Although trichothecene toxins are not required for the initial infection of wheat, they are involved in the progression of Fusarium Head Blight (FHB) disease.  Mutants of F. graminearum (tri5-) blocked in the first committed step in the trichothecene biosynthetic pathway do not produce deoxynivalenol (DON) or any other trichothecenes, and are reduced in virulence on wheat.  In order to test if biosynthetic precursors of DON are sufficient for disease progression, we disrupted the coding region sequence of 5 genes (FgTri1, FgTri3, FgTri8, FgTri11, and FgTri101) to produce mutants blocked at various steps in the trichothecene biosynthetic pathway.  The mutants were analyzed for production of trichothecenes in liquid media, in a rice solid medium, and in planta, and for ability to cause head blight on the FHB-susceptible wheat cultivar Wheaton.  Disruption mutants of the esterase FgTri8 did not show a significant reduction in virulence.  However, FgTri8- mutants accumulated 3,15-diacetylDON in culture, while in the infected seed DON as well as 3,15 diacetylDON was detected.  These results suggest that esterases in wheat can contribute to the deacetylation that produces DON following infection by strains that produce 3-acetylDON.  Disruptions of four genes, FgTri1, FgTri3, FgTri11, and FgTri101 blocked production of DON and led to the accumulation in culture of early pathway intermediates, such as isotrichodermol and its 3-acetylated derivative isotrichodermin, or calonectrin and its 3 and 15-deacetylated derivatives.  Disruption mutants of FgTri1, FgTri3, and FgTri101 were reduced in virulence.  However, disruption mutants of the cytochrome P450 monooxygenase FgTri11 retained wild-type virulence although they accumulated  isotrichodermol and isotrichodermin in culture and in infected seed.  In a previous study, both isotrichodermol and isotrichodermin were as phytotoxic as DON in an Arabidopsis thaliana bioassay.  Together, these results suggest that some trichothecene early intermediates are as biologically active as DON, thus the earliest steps of the pathway should be high priority targets for trichothecene control.


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