Genetic transformation of Gentiana dahurica Fisch by Agrobacterium tumefaciens using zygotic embryo-derived callus

Gentiana dahurica Fisch is one of four important commercial Radix Gentianae stipulated by the Chinese Pharmacopoeia. We have established a rapid and effective regeneration system using zygotic embryo-derived callus of G. dahurica Fisch. Using this regeneration system, Agrobacterium tumefaciens-mediated transformation of G. dahurica Fisch has been developed. Zygotic embryo-derived callus was infected with an A. tumefaciens strain (GV3130) harboring a pBI121 vector that contained an nptII selective marker gene. In a total of 60 zygotic embryo-derived calli assayed, frequency of calli with nptII gene PCR-positive transgenic plantlets is 5%. Transient glucuronidase (GUS) expression was observed from these transgenic plantlets. Frequency of GUS-positive transgenic plantlets (4/78) was approximately consistent with that of PCR assay (3/60). Our data indicate that we have successfully established a stable G. dahurica Fisch transformation system by A. tumefaciens. In general, this transformation system we have established might be useful for modifying physiological, medicinal and horticultural traits.