1a.Objectives (from AD-416):
1) Develop field tests at cooperating institutions of 'HoneySweet' and other Plum pox virus (PPV) resistant clones that USDA-ARS has developed. These will be compared with local PPV susceptible and tolerant, or resistant varieties for PPV resistance, fruit quality, yield, and other important agronomic traits.
2) Design new constructs that do not rely on the use of the GUS marker gene or the kanamycin antibiotic resistance (NPTII) selectable marker gene.
3) Transfer the technology for plum transformation to cooperating institutions in order that they can develop PPV resistance using germplasm of local varieties.
1b.Approach (from AD-416):
This activity will support efforts in setting up field tests in cooperating countries, collection of data from these tests, the development of a consensus document pertaining to the control of PPV through genetically engineered plums, and scientific interchanges between U.S. and European partners. In this way, the parties can develop data that is useful for both U.S. and European deregulation packages, and maintain the high level of interest and the collaborations that otherwise could falter in a non-supportive European environment.
The collaborating organization, the AgroBioInstitute, collaborated with the Black Sea Biotechnology Association and ARS in providing support and logistical assistance for the testing of Plum pox virus resistant plums under field conditions. This work provides important information to U.S. researchers seeking to develop resistant varieties for U.S. growers. Plans were formulated with the AgroBioInstitute to collaborate on using the 'FasTrack' plum breeding system for the production of PPV resistant transgenic plum varieties by hybridizing early flowering PPV resistant plum lines developed from 'HoneySweet' with plum varieties adapted to Bulgarian growing conditions and markets. Early flowering plum clones carrying the 'HoneySweet' PPV resistance gene are currently under test at ARS. Resistant early flowering clones will be provided to the collaborator for breeding. New resistant varieties adapted to European growing conditions would allow for a more robust development of PPV resistant GE plums for EU growers and a market for U.S.-developed GE plum products.