Abstract: In vitro aseptic bulb scales of Lilium lancifolium Thunb. were used as the explants to establish a highly efficient Agrobacterium-mediated genetic transformation system by slicing scales，optimizing the concentration and infection time of Agrobacterium solution，adjusting the composition of the suspension solution and co-culture medium. The results showed that MS + 1.5 mg ? L-1 6-BA + 0.5 mg ? L-1 NAA + 30 g ? L-1 sucrose was the optimized medium for the bud differentiation of scale slices，and adding 100 mg ? L-1 vitamin C in this medium can effectively inhibit the browning of scale slices and promote the proliferation of adventitious buds. For root induction，MS + 2.0 mg ? L-1 NAA + 30 g ? L-1 sucrose was the best medium choice. Antibiotic susceptibility testing revealed that the addition of 100 mg ? L-1 Kan or 75 mg ? L-1 Hyg in combination with 400 mg ? L-1 Cef in the medium was suitable for resistance screening. Taking the modified MS + 100 μmol ? L-1 AS as the suspension solution and the modified MS + 1.0 mg ? L-1 6-BA + 1.0 mg ? L-1 NAA + 100 μmol ? L-1 AS as co-culture medium，the final GUS histochemical staining indicated that the transient transformation efficiency and stable transformation efficiency can reach 81.72% and 25.2%，respectively，after inoculating scale slices in the Agrobacterium infection solution with OD600 = 0.4 for 15 min. Moreover，LrCCoAOMT gene cloned from L. regale Wilson was transformed into L. lancifolium Thunb. using this genetic transformation system，and transgenic positive plants were successfully obtained based on the molecular analysis and GUS staining.

Key words: Lilium lancifolium, genetic transformation, LrCCoAOMT gene, resistance improvement