Djordjevic M A, Zurkowski W, Shine J, Rolfe B G
J Bacteriol. 1983 Dec;156(3):1035-45. doi: 10.1128/jb.156.3.1035-1045.1983.
Two self-transmissible Sym(biosis) plasmids, one encoding pea-specific nodulation and nitrogen-fixation functions (plasmid pJB5JI) and the other encoding clover-specific nodulation and nitrogen-fixation functions (plasmid pBR1AN) were used to determine whether the symbiotic genes encoded on these plasmids are expressed in various members of the Rhizobiaceae. The host specificity of Rhizobium trifolii and R. leguminosarum Sym plasmid-cured strains could be directly determined by the transfer to these strains of the appropriate Sym plasmid. The nodulation of white clovers was restored by either plasmid pJB5JI or pBR1AN when these plasmids were transferred to two transposon Tn5-induced hair-curling (Hac-) R. trifolii mutants. In addition, lucerne nodulation was restored to a Hac- R. meliloti mutant when either plasmid pBR1AN or pJB5JI was transferred to this strain. The phenotype of nonmucoid (Muc-) Rhizobium mutants, which had altered cell surfaces, was not influenced by the transfer to these strains of plasmid pBR1AN or plasmid pJB5JI.
使用了两个自我传递的共生（Sym）质粒，一个编码豌豆特异性结瘤和固氮功能（质粒pJB5JI），另一个编码三叶草特异性结瘤和固氮功能（质粒pBR1AN），以确定这些质粒上编码的共生基因是否在根瘤菌科的各种成员中表达。通过将适当的Sym质粒转移到这些菌株中，可以直接确定三叶草根瘤菌和豌豆根瘤菌Sym质粒治愈菌株的宿主特异性。当质粒pJB5JI或pBR1AN转移到两个转座子Tn5诱导的卷毛（Hac-）三叶草根瘤菌突变体时，白三叶草的结瘤得以恢复。此外，当质粒pBR1AN或pJB5JI转移到该菌株时，紫花苜蓿结瘤恢复到Hac-苜蓿根瘤菌突变体。细胞表面发生改变的非黏液（Muc-）根瘤菌突变体的表型不受质粒pBR1AN或质粒pJB5JI转移到这些菌株的影响。
