1a. Objectives (from AD-416)
The objective of this project is to develop, through gene transfer technologies, stone fruits with resistance to Plum pox virus and an exotic invasive pathogen, rootstocks for fruit trees that will produce dwarf trees, and/or fruit with improved eating quality. The work at EPCOT falls under our research project plan.
1b. Approach (from AD-416)
Genetic engineering will be utilized to improve traits that have been either impossible or too time consuming to approach through traditional techniques. These traits include the development of dwarfing rootstocks for Pyrus (pear) and Prunus (stone fruits), the development of Plum pox virus resistant stone fruits, the improvement of fruit quality traits including the development of stoneless stone fruits, and the production of early flowering lines for speeding the fruit breeding process. We have developed a rapid high throughput transformation system in plum and a technology for early flowering and fruiting. We will use this system to rapidly test genes of interest. Those of interest will be applied for the improvement of stone fruits, particularly plum, and also pear. The genetically engineered plants developed at EPCOT will be further evaluated at Kearneysville in the greenhouse and field (with appropriate permits). The work at EPCOT is critical to us achieving our research project plan's milestones. The ARS staff at EPCOT is competent, motivated, and experienced. The facilities are good. We feel that achieving the objectives of the five-year-plan will provide not only good scientific information but also will lead us to the development of exciting new products for the pear and stone fruit industries.
3. Progress Report
Plums were transformed with various forms of a mutated plum gene, as well as a native pepper gene, to determine if the resulting plants would yield resistance to the Plum pox virus (PPV). Hundreds of plants were regenerated and transferred to the greenhouse. Plums were transformed with a construct to induce silencing of the PPV which resulted in resistance. Hundreds of plants were regenerated and transferred to the greenhouse. Plums were transformed with the early flowering genes from poplar. These plums were self compatible, meaning they could set fruit without needing to be pollinated with another pollen. Several transgenic lines were obtained, and these were clonally reproduced to have multiple plants. These were successfully transferred to the greenhouse and under evaluation for early flowering. The ADODR has monitored activities through emails, meetings, and calls.