用ＰＣＲ方法将广宿主范围质粒ＲＫ２中控制稳定性的片段ｐａｒＤＥ克隆到ｐＧＥＭ┐Ｔ载体上，然后插入到分泌表达载体ｐＥｘＳｅｃ１的ＢａｍＨＩ切点上，得到两个新载体ｐＺＬ２和ｐＺＬ３，其中ｐａｒＤＥ的转录方向分别与Ｔ７启动子相同和相反。经酶切物理图谱分析和ＰＣＲ扩增验证后，将ｐＺＬ２和ｐＺＬ３分别电击转化到成团泛菌３０８Ｒ中，在无抗生素的ＬＢ培养基中生长１００代后仍１００％地保留在细胞内。新质粒在植物叶面生长的细胞内也１００％稳定 The fragment of the control stability in broad host range plasmid RK2 was cloned into pGEM┐T vector by PCR and inserted into the BamHI cleavage point of the secretion expression vector pExSec1 to obtain two new vectors, pZL2 and pZL3, of which parDE transcription The same direction as the T7 promoter and vice versa respectively. After physical map analysis and PCR amplification validation, pZL2 and pZL3 were electroporated into Pantoea agglutina 308R, and remained 100% in the cell after 100 generations growth in antibiotic-free LB medium. The new plasmid is also 100% stable within the foliage of the plant