Study On Taxonomic Position And Nodulation Characteristic Of Strain XJ96077

Strain XJ96077 was isolated from root nodules of alfalfa (Medicago sativa)from Xinjiang Reigon. Nodulation experiments showed that both soybean and alfalfa were nodulated by XJ96077 effectively. The DNA G+Cmol% of strain XJ96077 was 61.9%. The DNA levels of homology between S .meliloti USDA1002, Rm41 and 042B were 93%, 86% and 80%, respectively. And ERIC-PCR fingerprinting analysis indicated XJ96077 was identical with other S.meliloti at similarity level of 71%. These results showed that XJ96077 belong to Sinorhizobium meliloti . To prove the capability of XJ96077 to nodulate both soybean and alfalfa, constitutively expressed green fluorescence protein gene gfp (carried by pMP2444) was introduced to XJ96077, and the recombinant strain XJ96077(G) was obtained. Root nodules of the soybean and alfalfa inoculated with XJ96077(G) and colony of XJ96077(G) were observed using the confocal laser scanning microscope, and the expressions of gfp were detected. XJ96077 showed various nodulation capacities with different soybean cultivars . XJ96077(GS) and XJ96077(GM) were isolated from root nodules of soybean and alfalfa inoculated with XJ96077(G), XJ96077,XJ96077(G),XJ96077(GS) and XJ96077(GM) were detected through plasmid electrophoresis. The results indicated that the exogenous plasmids in XJ96077(G), XJ96077(GM) and XJ96077(GS) had no change, but the copy of one indigenous plasmid increased.