Rose Transformation and Regeneration

A range of rose genotypes were evaluated for their propensity to regenerate via somatic embryogenesis. Results indicated that there was a very strong genetic component to this ability. This was confirmed by studying a F1 progeny of the cross between a genotype which regenerates readily via somatic embryogenesis and one that does not.

(Submitted for publication)

Somatic embryogenesis was initiated from in vitro-grown leaf explants of rose using an induction period of 4 weeks on MS basal medium supplemented with auxin followed by several subcultures on MS basal medium with cytokinin. ‘4th of July’ showed the highest regeneration frequency (24.4%) on 5.3 uM NAA followed by culture on medium containing 18.2 uM zeatin. ‘Tournament of Roses’ produced somatic embryos when cultured for 4 weeks on medium containing dicamba, 2.3 uM followed by three subcultures on medium containing 18.2 uM zeatin. Embryogenic callus matured on MS media containing 0.5 uM NAA, 6.8 uM zeatin, and 2.9 uM GA3. Long-term cultures were established for both cultivars. Somatic embryos germinated on MS medium containing IBA and BA. Silver nitrate (58.8 uM) enhanced shoot formation and germination of somatic embryos.

(In press)

Embryogenic calluses of Rosa hybrida cultivar 'Tineke' were transformed with Agrobacterium tumefaciens strain LBA4404 containing the binary vector pBIN m-gfp5-ER into which the virE/virG genes had been inserted. Visualization of GFP-expressing cells enabled visual selection of dividing, embryogenic cell clusters that were transgenic. When the Agrobacterium strain with the bifunctional fusion maker containing additional virE/virG genes was used, the number of green fluorescent calluses increased.

(In press)