SBIR-STTR Award

Raspberry bushy dwarf virus (RBDV) is the casual agent for the most widespread disease of raspberry. It can cause crumbly fruits, significant reduction in cane height, cane diameter and fruit yield. In the cultivar Meeker, which comprises about 70% of the production in the Pacific Northwest, crumbly fruits and yield reduction are the major effects of RBDV infection. The virus occurs throughout the raspberry growing regions of the world and has become an increasingly important problem over the past 10 years.Transmission of RBDV is associated with flowering and therefore, control is very difficult or impossible by chemical means. The only effective means of controlling the disease is to grow RBDV resistant cultivars. A genetic engineering approach through pathogen derived resistance (PDR) is proposed to develop RBDV resistance in red raspberry. The project is designed around a powerful combination of molecular and cell biology expertise from both industry and USDA. Coat protein and movement protein mediated resistance strategies will be applied to the cultivar, Meeker, which is very susceptible to RBDV.

Anticipated Results/Potential Commercial Applications of Research:
:The proposal research would generate RBDV resistant cultivars in red raspberry cv. Meeker. The planting of RBDV resistant cultivars in the field will enhance the yield per acre and fruit quality of raspberries. The successful strategy also would be applied to the development of RBDV resistance in other susceptible cvs. of raspberry. Commercial growers both in the United States and abroad would replace the susceptible varieties with the genetically modified varieties with resistance to RBDV. It is also anticipated that the genetic resistance developed through the proposed strategy might provide a broad spectrum resistance to various other viruses.

Raspberry bushy dwarf virus (RBDV) is the casual agent for most widespread disease of raspberry. It can cause crumbly fruits, significant reduction in cane height, cane diameter and fruit yield. In the cultivar Meeker, which comprises about 70% of the production in the Pacific Northwest, crumbly fruits and yield reduction are the major effects of RBDV infection. The virus occurs throughout the raspberry growing regions of the world and has become an increasingly important problem over the past 10 years. Transmission of RBDV is associated with flowering which makes control very difficult or impossible by chemical means. The only effective means of controlling the disease is to grow RBDV resistant cultivars. A genetic engineering approach designed around a powerful combination of molecular and cell biology expertise from both industry and USDA was funded by SBIR for the Phase I feasibility study. The preliminary results are very exciting and provide a strong basis to continue with the development of red raspberry cv. Meeker that is resistant to RBDV.

Anticipated Results/Potential Commercial Applications of Research:
The outcome of this research would generate red raspberry cv. Meeker resistant to RBDV. Our preliminary findings of Phase I showed 80% of the tested transgenic plants to be virus free following graft inoculation with infected plants. The planting of the varieties with resistance to RBDV can enhance the yield per acre and fruit quality of raspberries. It is anticipated that the successful strategy could also be applied to the development of RBDV resistance in other cultivars and also might provide a broad spectrum resistance to different viruses. Eventually the improved RBDV resistant varieties could replace the susceptible varieties used by commercial growers.