Gao W M, Yang S S
Microbiology (Reading). 1995 Aug;141(8):1957-1962. doi: 10.1099/13500872-141-8-1957.
A strain that forms effective nodules on soybean () and alfalfa () is described. The strain, 042B, was isolated from root nodules of alfalfa in Xinjiang Autonomous Region of China. Experiments showed that strain 042B was able to nodulate soybean as effectively as USDA110, a widely used inoculant strain. Under hydroponic conditions, both strains performed similarly in many respects such as time required for the appearance of nodules, total nitrogenase activity, plant top dry weight and total plant nitrogen. In soil pot experiments, total nitrogen, seed weight and seed nitrogen of soybean plants inoculated with strains 042B or USDA110 were much higher than those of the uninoculated control, but there were no differences between plants with strain 042B relative to strain USDA110. However, when strain 042B was the inoculant, the number of nodules was greater, but the nodules were smaller than those of strain USDA110. Results from ELISA showed that nodule occupancy of strain 042B in soybean ranged from 82-90% and that of strain USDA110 ranged from 78-86%. Strain 042B can grow in the presence of 5% (w/v) NaCl, at 42 °C, and at pH 10·7. Strain 042B was shown to have two large plasmids (molecular sizes 200 kb and > 1000 kb, respectively). The DNA G + C mol% of strain 042B was 63·6. The DNA level of homology between strain 042B and type-strain USDA1002 was 76%, while DNA homologies of strain 042B were 10% and 12% with USDA205 and USDA6, respectively.
本文描述了一种能在大豆（）和苜蓿（）上形成有效根瘤的菌株。该菌株042B是从中国新疆自治区的苜蓿根瘤中分离得到的。实验表明，菌株042B结瘤大豆的效果与广泛使用的接种菌株USDA110相当。在水培条件下，这两种菌株在许多方面表现相似，如出现根瘤所需的时间、总固氮酶活性、植株地上部干重和植株总氮含量。在土壤盆栽实验中，接种菌株042B或USDA110的大豆植株的总氮、种子重量和种子氮含量均显著高于未接种的对照，但接种菌株042B的植株与接种菌株USDA110的植株之间没有差异。然而，当以菌株042B作为接种剂时，根瘤数量更多，但根瘤比菌株USDA110的小。ELISA结果表明，菌株042B在大豆根瘤中的定殖率为82 - 90%，菌株USDA110的定殖率为78 - 86%。菌株042B能在5%（w/v）NaCl、42℃和pH 10.7的条件下生长。菌株042B含有两个大质粒（分子大小分别为200 kb和>1000 kb）。菌株042B的DNA G + C mol%为63.6。菌株042B与模式菌株USDA1002的DNA同源性为76%，而菌株042B与USDA205和USDA6的DNA同源性分别为10%和12%。
