论文部分内容阅读
在本工作中，通过平板筛选分离得到两个来自马铃薯的青枯假单胞菌菌株Ｔ２００２和Ｔ２０５３（对花生不致病）的利福平抗性自发突变株Ｔ２０１６和Ｔ２０１７，通过三亲本接合，ｐＧＸ１２５２分别以９．０７×１０－７、２．５４×１０－６频率被导入到Ｔ２０１６和Ｔ２０１７中，所得接合子Ｔ２１２３（Ｔ２０１６／ｐＧＸ１２５２）和Ｔ２１２４（Ｔ２０１７／ｐＧＸ１２５２）均分别能使花生汕油５２３发生青枯病，但它们侵染的植株出现病症的时间比Ｔ２００５晚３～５ｄ，说明ｐＧＸ１２５２能扩大Ｔ２０１６和Ｔ２０１７的寄主范围使之包括花生。从侵染Ｔ２１２３、Ｔ２１２４的病株中重新分离病菌，四环素抗性检测和质粒检测表明所有细菌均含有ｐＧＸ１２５２，说明在植物体内无抗生素选择压力情况下ｐＧＸ１２５２能在Ｔ２０１６、Ｔ２０１７中稳定存在。本工作进一步证实ｐＧＸ１２５２带有特异性控制青枯假单胞菌在花生上致病的与寄主专一性有关的基因。
In this work, two rifampicin-resistant spontaneous mutants T2016 and T2017 from Pseudomonas soongraum strain T2002 and T2053 from potato (non-susceptible to peanut) were isolated by plate screening. pGX1252 was introduced into T2016 and T2017 at frequencies of 9.07 × 10-7 and 2.54 × 10-6, respectively. The resulting clones T2123 (T2016 / pGX1252) and T2124 (T2017 / pGX1252) 523 showed bacterial wilt, but their infested plants showed symptoms 3-5 days later than T2005, indicating that pGX1252 could enlarge the host range of T2016 and T2017 to include peanuts. The bacteria were re-isolated from diseased T2123 and T2124 isolates. The tetracycline resistance test and plasmid detection showed that all the bacteria contained pGX1252, indicating that pGX1252 could stably exist in T2016 and T2017 without antibiotic selective pressure in plants. This work further confirmed that pGX1252 has a specific host-specific gene that controls the pathogenicity of Pseudomonas soongas.