Department of Microbiology, University of Hawaii, Honolulu, Hawaii 96822.
Appl Environ Microbiol. 1983 Oct;46(4):906-11. doi: 10.1128/aem.46.4.906-911.1983.
Several isolates from a newly described group of fast-growing acid-producing soybean rhizobia, Rhizobium japonicum, were analyzed for plasmid content. All contained from one to four plasmids with molecular weights of 100 x 10 or larger. Although most of the isolates shared plasmids of similar size, the restriction endonuclease (BamHI, EcoRI, and HindIII) patterns of the plasmids from three of the isolates were vastly different. Growth in the presence of acridine orange was effective in producing mutants cured of the largest plasmid in one of the strains. These mutants also lost the ability to form nodules on soybeans. High-temperature curing of a smaller plasmid in another strain did not lead to loss of nodulating ability or alteration of symbiotic effectiveness on soybean cultivars. The identities of all of the isolates and mutants were ascertained by immunofluoresence and immunodiffusion. The new fast-growing strains of R. japonicum may provide a better genetic system for the study of the soybean symbiosis than the slow-growing R. japonicum, not all of which can be shown to contain plasmids.
从新描述的快速生长产酸大豆根瘤菌群体中分离出的几个菌株，即 Rhizobium japonicum，对其质粒含量进行了分析。所有这些菌株都含有 100×10 或更大分子量的 1 到 4 个质粒。尽管大多数分离株含有相似大小的质粒，但来自三个分离株的质粒的限制内切酶（BamHI、EcoRI 和 HindIII）图谱却有很大的不同。在吖啶橙存在的情况下生长，有效地产生了一种菌株中最大质粒缺失的突变体。这些突变体也失去了在大豆上结瘤的能力。另一个菌株中较小质粒的高温失活并没有导致结瘤能力的丧失或对大豆品种共生有效性的改变。所有分离株和突变体的身份都通过免疫荧光和免疫扩散来确定。新的快速生长的 R. japonicum 菌株可能为大豆共生的研究提供一个比生长缓慢的 R. japonicum 更好的遗传系统，因为并非所有 R. japonicum 都能被证明含有质粒。
