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
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home 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
                                            Melnick, Rachelitem
                                            MARELLI, JEAN-PHILIPPE - M & M Mars Company - Brazilitem
                                            Sicher  Jr, Richarditem
                                            Strem, Maryitem
                                            Bailey, Bryan
  Submitted to: Tree Genetics and Genomes
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 4/19/2011
                                    Publication  Date: 5/17/2012
                                    Citation: Melnick, R.L., Marelli, J., Sicher, Jr., R.C., Strem, M.D., Bailey, B.A. 2012. The interaction of Theobroma cacao and Moniliophthora perniciosa, the causal agent of witches’ broom disease, during parthenocarpy. Tree Genetics and Genomes. DOI: 10.1007/s11295-012-0513-8.Interpretive Summary: Cocoa is combined with United States agricultural commodities providing a direct benefit to the American farmer. Witches’ broom disease, caused by the fungus Moniliophthora perniciosa, causes large yield losses for cacao (Theobroma cacao L.), the source of cocoa. When the fungus infects cacao flowers, it causes fruit to develop without fertilization, leading to seedless fruit and no cocoa beans. These seedless fruit rot and produce spores that spread the disease. We used microscopy, the molecular tool of quantitative real time PCR, and metabolite analysis to characterize how the fungus causes fruit to develop without seeds. The fungus grows throughout the seedless fruit causing significant changes in sugar and amino acid content without inducing a strong resistance response that would limit disease. Our improved knowledge of witches’ broom disease may lead to the development of new management tools for use by cacao farmers. It will provide cacao breeders with genetic markers to use during selection of resistant trees. By reducing the negative impact of disease on cacao yield, cocoa supplies may be stabilized resulting in increased benefits to the cocoa industry, and the American farmer.
                                Technical Abstract: Infection of Theobroma cacao L. flower cushions by Moniliophthora perniciosa induces parthenocarpy. Healthy and parthenocarpic immature cacao pods were obtained from seven cacao clones. Microscopic observations of parthenocarpic pods confirmed fruits lack viable seed. Septate mycelium colonized parthenocarpic pods, but were absent from healthy pods. Parthenocarpic pods had increased concentrations of leucine, methionine, serine, phenylalanine, and valine. Major transport metabolites sucrose and asparagine were decreased by 63% and 40%, respectively, during parthenocarpy. M. perniciosa ESTs related to detoxification (MpSOD2 and MpCTA1) and nutrient acquisition (MpAS, MpAK, MpATG8, MpPLY, and MpPME) were induced in parthenocarpic pods. Most M. perniciosa ESTs related to plant hormone biosynthesis were repressed (MpGAox, MpCPS, MpDES, MpGGPPS, and MpCAO) during parthenocarpy at the stage studied. QPCR analysis was conducted for 54 defense related cacao ESTs and 93 hormone related cacao ESTs. Specific cacao ESTs related to plant defense were induced (TcPR5, TcChi4, TcThau-ICS) while others were repressed (TcPR1, TcPR6, TcP12, and TcChiB). Cacao ESTs related to GA biosynthesis (TcGA20OX1, TcGA20OX1B, and TcGA20OX3a) were repressed in parthenocarpic pods. Cacao ESTs putatively related to cytokinin (TcCKX3 and TcCKX5) and IAA (TcGH3.6, TcGH3.17b, TcGH3.1, TcARF18) homeostasis were induced in parthenocarpic pods, suggesting an attempt to regulate cytokinin and auxin concentrations.


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