摘要
本实验以042B 的 DNA 转化 ROG31细胞,在以0.2 mol/L NaCl 为选择标记的YMA 培养基上,获得37个耐盐的菌落,纯化后又经30代的转管移植,有8株转化子获得了稳定的耐盐性,再将这8株转化子回接红豆草植株,得到1株耐0.4 mol/L NaCl 和固氮能力较好的红豆草根瘤菌 ROt6。供体菌042B 和转化子 ROt1和 ROt6在0.3 mol/L NaCl 培养基中生长时,细胞内积累大量谷氨酸。
Rhizobium strain ROG31 isolated from the root nodules of sainfoin(Onobrychis viciaefolia)in Gansu province is sensitive to 0.1 tool/L NaCl and less efficient in nitrogen fixation. Alfalfa rhizobium 042B can grow in YM liquid medium containing 0.8 mol/L NaCl,and has high activi- ty of symbiotic nitrogen fixation.Thirty seven transformants were obtained by transforming the DNA from strain 042B into the cells of strain ROG31 and selected on YMA medium with 0.2 mol/L NaCl as seleceive marker.However,only eight transformants maintained stably the characteri sties of salt tolerance after 30 transfers of the cultures.Inoculation experiments showed that the sainfoin rhizbium strain named ROt6 fixed nitrogen more efficiently and tolerated 0.4 mol/L NaCl.Intracellular free glutamate increased rapidly in strain 042B and transformant ROt1 as well as ROt6 grown on medium containing 0.3 mol/L NaCl.
关键词
耐盐性
红豆草
根瘤菌
改造
DNA transformation
salt tolerance
sainfoin rhizobia
