Construction of Tn5 transposon insertion mutants of Ralstonia solanacearum isolated from Pogostemon cablin / 中国中药杂志

Ralstonia solanacearum strain PRS-84 used in this study was isolated from diseased Pogostemon cablin plants in our previous study.The competent cells of R.solanacearum strain PRS-84 were transformed by electroporation with Tn5 transposon and then were plated on TTC agar plates containing kanamycin to select for kanamycin-resistant colonies.The detection of kanamycin-resistant gene in kanamycin-resistant colonies was performed by PCR.Further,the flanking fragments of Tn5 transposon insertion site in the mutants were amplified by inverse PCR,and the flanking fragments were sequenced and analyzed.The results indicated that the kanamycin-resistant colonies were obtained in the transformation experiment of R.solanacearum strain PRS-84 by electroporation with Tn5 transposon.A specific band of approximately 700 bp was amplified by PCR from kanamycin-resistant colonies.The flanking sequences of Tn5 transposon insertion site in the transformants were obtained by inverse PCR.After sequencing and sequence analysis of Tn5 transposon insertion site in mutants,we preliminarily speculated that the Tn5 transposon inserted in the typ A gene,rec O gene and gid A gene in three mutants,respectively.A random mutagenesis system of R.solanacearum strain PRS-84 by electroporation with Tn5 transposon has been established,and the Tn5 insertion mutants have been obtained.This study might facilitate the creation of mutant library and the discovery of the virulence gene of R.solanacearum isolated from P.cablin.

Highly effective transformation of Cryptococcus neoformans / 第二军医大学学报

Objective: To establish a highly effective transformation method of Cryptococcus neoformans. Methods: Special reagents was used to make C. neoformans take in external DNA under given condition. This chemical transformation result was compared with that of electrotransformation. The feasibility of this chemical transformation was tested by plasmid stability test. Results: The efficiency of this chemical transformation was more than 103 transformants/?g plasmid DNA, far more than that of the traditional electrotransformation. Conclusion: An appropriate transformation method is established for C. neoformans transformation, which has high transformation efficiency.