PRODUCTION OF HERBICIDE-RESISTANT HIGHBUSH BLUEBERRY ‘LEGACY’ BY AGROBACTERIUM-MEDIATED TRANSFORMATION OF THE BAR GENE

The chimeric bialaphos resistance (bar) gene driven by the nos promoter was introduced into highbush blueberry, Vaccinium corymbosum L. ‘Legacy’, using Agrobacterium tumefaciens-mediated transformation (Song and Sink, 2004). Twenty-one out of 300 leaf explants inoculated with A. tumefaciens strain EHA105:pGTV-BAR regenerated shoots after selection on modified Woody Plant Medium + 1.0 mg L^-1 TDZ + 0.5 mg L^-1NAA + 250 mg L^-1 timentin + 0.1 mg L^-1 glufosinate ammonium (GS). Cloned shoots of randomly selected and PCR-positive transgenic lines L18, L21, L22 and L25 showed resistance to a higher level of GS at 5.0 mg L^-1 during chlorophenol red assays and were studied further.
The integration and expression of the bar gene in these 4 lines was confirmed by Southern hybridization and by phosphinothricin acetyltransferase (PAT) assays.
L18, L21 and L22 lines each had a single copy and L25 had three copies of the bar gene.
Herbicide glufosinate at four levels (GS in mg L^-1: 0, 750, 1500 and 3000) was applied using a track sprayer on 8-month old plants growing in planting medium.
Evaluations done after 2 weeks indicated that at the high-dose of GS (3000 mg L^-1), 4 times the standard level for field application, the percents of leaves with no injury symptoms were 70%, 77%, 97% and 71%, respectively, for L21, L22, L18 and L25. Only 7% of the leaves on non-transgenic plants had no injury and 66% abscised.
These results indicate that the bar gene may serve both as a selectable marker and/or for herbicide-resistance for blueberry as currently being further evaluated in a field trial.

International Symposium on Biotechnology of Temperate Fruit Crops and Tropical Species

G.-Q. Song, R.A. Roggers, K.C. Sink, M. Particka, B. Zandstra

chlorophenol red, EHA105, glufosinate, phosphinothricin, PCR, small fruit crop

https://doi.org/10.17660/ActaHortic.2007.738.48