|Authors: ||R.R. Martin, H. Mathews|
|Keywords: ||Raspberry bushy dwarf virus, RBDV, ELISA, Transgenic Raspberry, RT-PCR, Southerns|
Widespread crumbly-fruited red raspberry (Rubus idaeus L.) was first reported by growers in northern Washington in 1995. Crumbly fruit was associated with Raspberry bushy dwarf virus (RBDV) infection in the Fraser Valley, though the plants did not show any foliar symptoms.
Three fields in the Fraser Valley and three fields in southern Washington that had been tested in 1996 were retested in 1998. In the Fraser Valley, the incidence of RBDV went from 0%, 0%, and 2.3% in 1996 to 55%, 17% and 83%, respectively, in 1998. In southern Washington, the incidence of RBDV in the three fields tested in 1996 and 1998 was near 4% and did not change significantly over the two year period.
There is a need to develop a RBDV resistant raspberry cultivar.
The coat protein and movement protein open reading frames of a local isolate of RBDV was sequenced.
Using site directed mutagenesis, four mutations were created in the movement protein.
These movement protein mutants as well as wild type movement protein and coat protein genes were cloned into a plant expression vector and inserted into Agrobacterium tumefaciens. Transformation of the six constructs into ‘Meeker’ raspberry has been carried out and the plants established in field plots, as well as being maintained in tissue culture and in a screenhouse.
Grafting the transformants with RBDV infected material has been started and 53 of 141 transgenic lines have remained free of RBDV after two rounds of grafting.
Reverse Transcriptase – Polymerase Chain Reaction (RT-PCR) tests and Southern analysis have been done on a subset of plants to ensure that the genes are present and that the DNA is being transcribed.
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