Published online by Cambridge University Press: 12 February 2007
Regeneration of sweet potato (Ipomoea batatas cv. Lizixiang) transgenic plants with oryzacystatin-I (OCI) gene was achieved using an Agrobacterium tumefaciens-mediated method. A. tumefaciens strain LBA4404, harbouring a binary vector pBinh with neomycin phosphotransferase II and OCI genes, was used. After 3 days of subculture, Lizixiang embryogenic suspension cultures were co-cultivated with LBA4404 (OD600nm=0.5) for 4 days. Next, the infected suspension cultures were first cultured for 5 days in MS medium with 2 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 300 mg/l carbencillin (Carb) but without kanamycin (Kan) and then transferred to MS medium supplemented with 2 mg/l 2,4-D, 50 mg/l Kan and 300 mg/l Carb for the selection culture. Four weeks after selection, 200 Kan-resistant cell aggregates (∼1 mm in size) from the embryogenic suspension cultures were transferred to MS solid medium supplemented with 2 mg/l 2,4-D, 50 mg/l Kan and 300 mg/l Carb, and eight embryogenic calluses were obtained. After transferring to MS medium supplemented with 1 mg/l ABA, 50 mg/l Kan and 100 mg/l Carb, these embryogenic calluses formed 13 plantlets via somatic embryogenesis. PCR and PCR–Southern blot analysis indicated that seven of the 13 plantlets were transgenic.