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 Northeast Area Geneva, New York Plant Genetic Resources Unit (PGRU) 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
                                            DREESEN, ROZEMARIJN - KULEUVEN DIVISION OF CROPitem
                                            VANHOLME, BARTEL - GHEN UNIVERSITYitem
                                            LUYTEN, KATRIEN - KULEUVEN DIVISION OF CRitem
                                            VAN WYNSBERGHE, LOBKE - KULEUVEN DIVISION OF CRitem
                                            Fazio, Gennaroitem
                                            ROLDAN-RUIZ, ISABEL - INSTITUTE FOR AGRICULTURAitem
                                            KEULEMANS, JOHAN - KULEUVEN DIVISION OF CR
  Submitted to: Molecular Ecology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 3/28/2009
                                    Publication  Date: 2/19/2010
                                    Citation: Dreesen, R., Vanholme, B., Luyten, K., Van Wynsberghe, L., Fazio, G., Roldan-Ruiz, I., Keulemans, J. 2010. Analysis of Malus S-RNase gene diversity based on a comparative study of European wild apple, old and modern apple cultivars. Molecular Ecology. Molecular Breeding DOI: 10.1007/s11032-010-9405-5.Interpretive Summary: Apple flowers cannot self fertilize.  This is due to the presence of genes (S-RNAses) that prevent pollen from fertilizing apple flowers that have the same genes.  Because of this phenomenon, new forms of these genes are always being promoted through mutation and natural selection.  This study has identified new forms of this gene in wild apple species and shown that there has been a significant loss in diversity due to domestication.  This study also elucidates the functional structures of the S-RNAse protein by modeling tertiary structures.
                                Technical Abstract: Malus S-RNase genetic diversity was analyzed under natural circumstances (Malus sylvestris) and controlled mating (Malus x domestica). By PCR-based methods the S-RNase genotype of 196 European wild apple trees (M. sylvestris) from 12 sites, 140 M. x domestica cultivars and 27 interspecific hybrids was determined. Thirty-six different S-alleles were identified in M. sylvestris, compared to 27 and 17 in old and modern M. x domestica cultivars indicating the negative influence of domestication and breeding on S-RNase diversity. Study of S-allele diversity within the M. sylvestris geographical subgroups showed that Malus S-allele differentiation is high and that S-allelic frequencies are in equilibrium. A significant part (12.5%) of the M. sylvestris S-RNase alleles remains unknown. The majority of the known S-alleles are shared by both species which illustrates their close relatedness. 16 potentially novel allelic sequences, mostly unique for M. sylvestris, were identified.

Genealogical analysis shows that 5 of these novel alleles form a separate clade with S5 and S34. By comparison of Malus S-RNase sequence information, S-RNase genetic diversity was further explored.

Despite extreme length polymorphisms, the extremities of the single intron region tend to be much conserved. Alignment of deduced partial protein sequences shows that only one residue –being a cysteine- is conserved in the Malus S-RNase PS1-region. Based on a modeled tertiary structure of S4-RNase, we concluded that this is essential for the anchoring of a loop to the protein core providing additional stability to the secreted protein.


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