一株能在苜蓿上结瘤的费氏中华根瘤菌

费氏中华根瘤菌 (Sinorhizobiumfredii) 0 4 2BS分离自新疆的苜蓿根瘤 ,通过交叉结瘤试验 ,发现它既可在苜蓿上又可在大豆上结瘤固氮。 1 6SrDNAPCR RFLP分析表明 ,0 4 2BS与费氏中华根瘤菌模式菌株USDA2 0 5的 4种限制性酶切图谱完全一致。其G +Cmol%为 60 0 ,与费氏中华根瘤菌USDA2 0 5和USDA1 91的DNA同源性分别为 84 9%和89 6% ,表明 0 4 2BS属于费氏中华根瘤菌。应用绿色荧光蛋白基因标记 0 4 2BS ,得到重组菌株 0 4 2BSG。将其接种保定苜蓿和北引 1号大豆 ,并重新分离出根瘤菌 ,利用激光共聚焦荧光显微镜检测到标记基因的表达 ,从而确证了 0 4 2BS能在苜蓿和大豆上结瘤。而且 ,0 4 2BS对不同苜蓿品种的结瘤能力不同

A SINORHIZOBIUM FREDLL STRAIN THAT EFFECTIVELY NODULATE MEDICAGO SATIVA

Sinorhizobium fredii 042BS was isolated from root nodules of alfalfa (Medicago sativa) from Xinjiang Region. Nodulation experiments showed that both soybean and alfalfa were nodulated by 042BS effectively. The 16S rDNA PCR-RFLP analysis was carried out by four restriction endonucleases, and the restriction maps of strain 042BS were identical with those of S. fredii USDA205. The DNA G + C mol% of strain 042BS was 60.0. The DNA homology between 042BS and S. fredii USDA205 and USDA191 were 84.9% and 89.6%, respectively. To prove the capability of 042BS to nodulate both soybean and alfalfa, constitutively expressed green fluorescence protein gene(gfp) was introduced to 042BS, and the recombinant strain 042BSG was obtained. The reisolates from nodules of the soybean and alfalfa inoculated with 042BSG were observed using the confocal laser-scanning microscope, and the expressions of gfp were detected, respectively. 042BS showed various nodulation capacities with different alfalfa cultivars used.