In this study,cowpea trypsin inhibitor (CpTI) gene, an insecticidal gene,was introduced into two Populus tomentosa clones by gene transformation mediated by Agrobacterium tumefaciens. The transformed regeneration shoots were obtained directly by leaf discs.In order to established selection condition,leaf discs were cultured in the medium with increasing concentration kanamycin.Kanamycin resistant(km r)plantlets were obtained by 3～4 cycles screening in selective condition.Then transformed shoots were rooted in the medium containing kanamycin 50?mg/L and transferred to greenhouse.The presence of CpTI gene in transgenic plants were confirmed by PCR and PCR\|Southern blot.
