HERBICIDE-RESISTANT TRANSGENIC SUGARCANE PLANTS CONTAINING THE BAR GENE

We have obtained herbicide resistant transgenic sugarcane plants (Sacc harum spp. hybrids) of the commercial cultivar NCo 310. A particle inf low gun was used to bombard embryogenic calli obtained from immature i nflorescences with microprojectiles coated with a plasmid containing t he coding region of the bar gene fused to the maize ubiquitin-1 (Ubi-1 ) promoter, first exon, and first intron. Shoots were regenerated from calli selected for resistance to bialaphos (1 mg/L), and rooted on he rbicide-containing medium (3 mg/L). Plants regenerated on selective me dia were screened for the presence of the bar gene by polymerase chain reaction. Northern blot analysis showed that transgenics were produci ng chimeric transcripts of the proper size. Most of the transformants examined displayed resistance to the commercial herbicide Ignite appli ed either to leaf segments or to the entire plant at dosages lethal to nontransformed controls. Southern blot analysis confirmed stable inte gration of three to 10 copies of the transgene into the sugarcane geno me. A well-characterized transformant was submitted to three rounds of vegetative propagation, as well as through meristem culture. All resu lting propagated clones displayed herbicide resistance comparable to t he original transformant. The above results demonstrate that the bar g ene can be an effective selectable marker in sugarcane transformation studies.