论文部分内容阅读
华癸中生根瘤菌(Mesorhizobium huakuii)7653R是分离自我国南方水稻田的一株根瘤菌,含有2个内源质粒:p7653Ra和p7653Rb,其中7653Rb是共生质粒。通过Tn5-sacB的插入方法来消除质粒,获得7653Rb消除的突变株7653RD。将豌豆根瘤菌T83K3的共生质粒pJB5JI导入7653R和7653RD中,盆栽结果表明含有pJB5JI的转移接合子7653R-197的竞争结瘤能力和共生固氮能力均高于7653R。pJB5JI不能恢复7653RD在紫云英上的结瘤能力。含有pJB5JI的7653RD可以在豌豆上结无效瘤,表明pJB5JI可以在7653R的染色体背景下表达其功能。对转移接合子中的质粒稳定性进行检测,结果表明pJB5JI在人工传代的情况下可以稳定存在,但经过共生之后发生了遗传分离,对转移接合子和出发菌株及分离菌株进行kan基因的PCR扩增,除了受体菌外其他菌株都可得到PCR产物,由此推测,pJB5JI可能部分或全部整合到了受体菌的染色体基因组中。
Mesorhizobium huakuii 7653R is a rhizobia isolated from rice fields in southern China and contains two endogenous plasmids, p7653Ra and p7653Rb, of which 7653Rb is a symbiotic plasmid. Plasmids were eliminated by Tn5-sacB insertion, resulting in 7653Rb mutant 7653RD. The symbiotic plasmid pJB5JI of pea Rhizobium T83K3 was introduced into 7653R and 7653RD. The results of pot experiment showed that the competitive nodulation ability and symbiotic nitrogen fixation capacity of 7J593R-197 with pJB5JI was higher than that of 7653R. pJB5JI can not recover the nodulation capacity of 7653RD on Aster. 7653RD containing pJB5JI can cause nodules on peas, suggesting that pJB5JI can express its function in the 7653R chromosomal context. The plasmid stability in the transconjugants was examined. The results showed that pJB5JI could stably exist in the case of artificial passage, but after the symbiosis, genetic segregation occurred, and the kan gene was PCR-amplified in the transconjugants, the starting strains and the isolates The results showed that pJB5JI may be partially or fully integrated into the chromosome genome of recipient bacteria.