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用含有转座子Ｔｎ５ 的铜绿假单胞杆菌ＰＡＯ１８２６（ｐＭＯ７５ ∷Ｔｎ５ ，Ｋｍｒ） 诱变我国马铃薯青枯菌小种３ 号菌株ＰＯ４１ ，获得６０００ 多个胞外多糖正常产生的接合子。经ＳＤＳＰＡＧＥ 电泳，筛选出２ 个胞外蛋白减少９ 种的突变株ＰＭ２６４４ 和ＰＭ２３９ ，其可以引起烟草叶片典型的过敏性反应，致病力比野生型菌株显著降低，皆为原养型菌株。Ｓｏｕｔｈｅｒｎ 杂交的结果表明，突变株染色体上只有１ 个转座子插入位点。标记交换证明，９ 种胞外蛋白缺失与转座子插入相偶联的频率为１００ ％ 。以聚半乳糖醛酸酶和内葡聚糖酶２ 种胞外酶为指示蛋白进行定量测定的结果表明，在突变株上清液中和菌体细胞内都没有这２种胞外酶的存在。以突变株ＰＭ２６４４ 为受体菌，通过基因功能互补的方法，从野生型青枯菌基因文库筛选到２ 个阳性克隆ｐＰＳＰ１ 和ｐＰＳＰ２ ，它们既能恢复２ 个突变株产生胞外蛋白的能力，也能将２ 个突变株的致病力恢复到接近野生型菌株的水平。
The Pseudomonas solanacearum 3 strain PO41 was mutagenized with Pseudomonas aeruginosa PAO1826 (pMO75 :: Tn5, Kmr) containing transposon Tn5 to obtain more than 6,000 extracellular polysaccharides. After SDS-PAGE electrophoresis, two PM2644 and PM239 mutants were screened out, which could cause typical hypersensitive reaction in tobacco leaves, and their pathogenicity was significantly lower than that of wild-type strain, all of which were prototrophic strains . Southern hybridization results showed that there was only one transposon insertion site on the chromosome of the mutant strain. Label exchange demonstrated that the frequency of 9 extracellular protein deletions coupled with transposon insertion was 100%. Polygalacturonase and endoglucanase two kinds of extracellular enzymes as indicators of protein quantitative determination results show that in the mutant supernatant and bacterial cells in the absence of these two extracellular enzymes . Two mutant clones, pPSP1 and pPSP2, were screened from the wild type R. solani gene library by using the mutant strain PM2644 as a recipient. The two strains were able to recover the ability of two mutant strains to produce extracellular proteins, The pathogenicity of the two mutant strains can be restored to the level of the wild type strain.