Progress 10/01/05 to 09/30/06
Outputs
Progress Report 4d Progress report. This final report serves to document research conducted under Specific Cooperative Agreement #58-1920-1-132 between ARS and Clemson University (Project #1920-22000-028-01S) under Congressional Mandate in the FY 2001 Appropriations Bill for Plum Pox control. Plum pox potyvirus (PPV) presents one of the most important disease problems in stone fruit production worldwide, and efforts to develop resistant cultivars are a high research priority. Over the four years of this project, cooperators at Clemson University have mapped a putative resistance gene in 'Stark Early Orange' and converted markers flanking the resistance gene into markers useful for testing if this resistance gene is generally conferring resistance to PPV in other germ plasm resources. These markers are being used in marker assisted selections of apricot in Spain in collaboration with the laboratory of M. Badenes (IVIA, Valencia). A resistance map for Prunus has
been developed which currently contains 42 putative resistance regions. Integration of the maps of other laboratories through markers developed at Clemson has allowed initiation of investigations to obtain resistance genes from apricot, and in parallel we have identified the same region in peach for comparative studies. Clemson researchers have determined that the region conferring resistance in apricot is duplicated on linkage group 5 and this region is known to confer resistance to powdery mildew in peach. Clemson researchers have built up the genomic resources necessary to begin searching for resistance genes and have identified several genes that are potential candidates for the resistance. An International Consortium has been developed that will be devoted to obtaining resistance to PPV in fruit trees. Work completed under this SCA has furthered our understanding of the genetic basis of resistance to PPV in apricot and developed markers useful to plant breeders for
incorporating resistance in other Prunus species. Results of the research has been documented in 2 published manuscripts, a Ph.D. thesis dissertation, 9 oral presentations, and one poster at local, national, and international meetings.
Impacts
(N/A)
Publications
|
Progress 09/01/01 to 08/31/06
Outputs
Progress Report Objectives (from AD-416) Utilize molecular marker systems to tag gene(s) controlling resistance to plum pox virus in apricot, thereby facilitating the introgression of these genes into other cultivars and potentially into other Prunus species; having identified markers close to the resistance genes, utilize this information in conjunction with structural and functional genomic efforts in peach and apricot to initiate cloning and characterization of the resistance genes. Approach (from AD-416) Utilizing the mapping populations identified by European colleagues, use amplified fragment length polymorphism (AFLP) technology on mapping populations of 'Stark Early Orange' and 'Harlayne' to identify markers linked to virus resistance. These markers will be mapped on different apricot molecular maps to determine the number of marked resistance loci. Using BAC libraries of apricot and peach, these markers will be converted to microsatellite markers to facilitate marker-assisted selection in breeding programs. Initiate cloning and identification of resistance genes and mobilize these genes into other cultivars and species through marker assisted breeding and transgenic technologies. Significant Activities that Support Special Target Populations Plum pox potyvirus (PPV) presents one of the most important disease problems in stone fruit production worldwide, and efforts to develop resistant cultivars are a high research priority. Over the five years of this project, cooperators at Clemson University have mapped a putative resistance gene in �Stark Early Orange� and converted markers flanking the resistance gene into markers useful for testing if this resistance gene is generally conferring resistance to PPV in other germ plasm resources. These markers are being used in marker assisted selections of apricot in Spain in collaboration with the laboratory of M. Badenes (IVIA, Valencia). A resistance map for Prunus has been developed which currently contains 42 putative resistance regions. Integration of the maps of other laboratories through markers developed at Clemson has allowed initiation of investigations to obtain resistance genes from apricot, and in parallel we have identified the same region in peach for comparative studies. Clemson researchers have determined that the region conferring resistance in apricot is duplicated on linkage group 5 and this region is known to confer resistance to powdery mildew in peach. Clemson researchers have built up the genomic resources necessary to begin searching for resistance genes and have identified several genes that are potential candidates for the resistance. An International Consortium was developed that was devoted to obtaining resistance to PPV in fruit trees. Work completed under this SCA has furthered our understanding of the genetic basis of resistance to PPV in apricot and developed markers useful to plant breeders for incorporating resistance in other Prunus species. Results of the research has been documented in 2 published manuscripts, a Ph.D. thesis dissertation, 9 oral presentations, and one poster at local, national, and international meetings. This research was accomplished in cooperation with Project 1920-22000-028-00D under National Program 303 (Plant Diseases), Component 1, Problem Statement 1B: Detection, Identification, Characterization, and Classification of Pathogens. The current SCA was terminated after five years and converted to a no-cost agreement.
Impacts
(N/A)
Publications
|
Progress 10/01/04 to 09/30/05
Outputs
4d Progress report. This report serves to document research conducted under Specific Cooperative Agreement #58-1920-1-132 between ARS and Clemson University (Project #1920-22000-028-01S) under Congressional Mandate in the FY 2001 Appropriations Bill for Plum Pox control. Additional details of research can be found in the parent CRIS 1920-22000-028-00D, Identification, tagging, and characterization of resistance genes to PPV in prunus species under NP 303. Plum pox potyvirus (PPV) presents one of the most important disease problems in stone fruit production worldwide, and efforts to develop resistant cultivars are a high research priority. Cooperators at Clemson University have been screening simple sequence repeat (SSR) markers and have developed a general resistance map for Prunus that includes putative resistance regions in 7 of the 8 linkage groups, similar to work being conducted in Europe. Peach and apricot physical maps have been oriented to the general Prunus
map, additional SSR marker data are being analyzed, and fine mapping of the plum pox resistance region in linkage group 1 is progressing. Identification of the exact resistance loci will facilitate incorporation of resistance genes from apricot to peaches and other Prunus genomes.
Impacts
(N/A)
Publications
|
Progress 10/01/03 to 09/30/04
Outputs
4. What were the most significant accomplishments this past year? D. Progress Report: This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Clemson University under Congressional Mandate in the FY 2001 Appropriations Bill for Plum Pox control. Additional details of research can be found in the report for the parent CRIS 1920-22000-028-00D, entitled "Identification, characterization, and control of new and emerging insect-transmitted plant pathogens". Plum pox potyvirus (PPV) is one of the most important problems in fruit production worldwide. Laboratories in Europe have searched for resistance in Prunus germ plasm and have found a limited number of apricot cultivars with high levels of natural resistance to the virus. Effective control of the disease will require cultivars resistant to PPV. Breeding programs aimed at obtaining new cultivars resistant to PPV with good agronomic and commercial quality are in progress
and several breeding programs in Europe have been instrumental in this area. It is evident from earlier studies that timely control of PPV with resistant cultivars will rely on classical breeding approaches with modern technologies for marking and identifying resistance genes. The most significant accomplishment this past year was the screening of simple sequence repeat (SSR) markers that were derived from converted AFLP markers flanking a putative Plum Pox Virus resistance gene in 'Stark Early Orange'. A total of 8 SSR's have been screened in 4 different apricot crosses, 'Vestar' X 'LE3246', 'Stark Early Orange' X 'LE3218', 'Goldrich' X 'Valenciano', and 'Lito' X 'Lito' in cooperation with our European partners to determine if they mark resistance loci in the different germplasm resources. We have mapped 3 of these SSRs in the 'LE3246' map and 4 in the 'Vestar' map. Mapping in the 'Goldrich' and 'Lito' crosses is underway. We have continued to map the homologous region of
resistance in peach as compared to the 'Stark Early Orange' putative resistance locus as part of an effort to utilize the peach genome database as a tool to facilitate identification of genomic regions of Prunus genomes containing putative resistance genes to this virus and other pathogens. Thus we have also identified the peach BACs that carry the AFLP markers identified in apricot as flanking the PPV resistance locus. We are currently trying to determine the physical map location of these BACs. In cooperation with V. Decroocq of the INRA Bordeaux, we are examining this region and others of the peach genome for the presence of classical RGA type resistance genes and other genes known to confer resistance to pathogens in other systems. We have identified 29 map locations for resistance related genes distributed among 7 of the 8 linkage groups of peach. This candidate gene approach may speed the approach of finding the resistance genes in the marked genomic regions of apricot.
Impacts
(N/A)
Publications
|
|