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
 Crops Pathology and Genetics Research: Davis, CA
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    Outreach Events
                        UC Davis Picnic Day
                                    Kinders go to College
                                    STEM Girls
                                    Future Scientist Program
                                    Agriculture Future of America
                                    Wallace-Carver Fellowship
                                    Young Scholars Program
                                    Annual Awards Banquet
                    About Us
                        About Us
                                    Our Mission
                                    Principal InvestigatorsSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Pacific West Area Davis, California Crops Pathology and Genetics 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
- Etiology and Biology of Tree Crop Diseases
- Rice Genetics
- Sustainable Floriculture
- Sustainable Viticulture

Title:   Author  item
                                            McClean, Aliitem
                                            SUDARSHANA, PADMA - USDA,ARS,CPGRUitem
                                            Kluepfel, Daniel
  Submitted to: Walnut Research Conference
                                    Publication Type: Proceedings
                                    Publication Acceptance Date: 1/1/2007
                                    Publication  Date: 1/1/2007
                                    Citation: Mcclean, A.E., Sudarshana, P., Kluepfel, D.A. 2007. Real-time pcr detection and development of a bioassay for the deep bark canker pathogen, brennaria rubrifaciens. Walnut Research Conference.Interpretive Summary:
                                Technical Abstract: Deep Bark Canker (DBC), caused by the bacterium Brennaria rubrifaciens afflicts English walnut cultivars and is characterized by late onset of symptoms in trees greater than 15 years old.  These symptoms include deep bleeding vertical cankers along the trunk and larger branches that exude a bacterial-laden reddish brown sap. B. rubrifaciens produces a unique water-soluble red pigment called rubrifacine when cultured in the laboratory.  Here we describe the new primer pair, BR-1 and BR-3 that amplify a unique 409bp region of the 16S rDNA sequence that facilitates the sensitive and specific detection of B. rubrifaciens.  Using these primers in a realtime-PCR system we were able to detect as few as 8 B. rubrifaciens colony forming units (CFU).  A survey of 11 antibiotics revealed that B. rubrifaciens is resistant to erythromycin and novobiocin at 10 mg/L and 30 mg/L respectively.  Amending the cultivation medium with these antibiotics has improved the semi-selective cultivation of B. rubrifaciens on solid media.  Both walnut cultivars, Hartley and Chandler, grown in tissue culture are susceptible to infection by B. rubrifaciens.  With in 21 days after inoculation Hartley shoots turned necrotic and died.  Chandler shoos exhibited a similar phenotype 10wk after inoculation.  This latter finding will be useful in our search for Brennaria genes involved in pathogenesis and the identification of walnut genotypes resistant to deep bark canker.


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