Cevallos M A, Vázquez M, Dávalos A, Espín G, Sepúlveda J, Quinto C
Departamento de Biología Molecular de Plantas, Centro de Investigacíon sobre Fijación de Nitrógeno, Morelos, México.
Mol Microbiol. 1989 Jul;3(7):879-89. doi: 10.1111/j.1365-2958.1989.tb00237.x.
Two nodulation regions from the symbiotic plasmid (pSym) of Rhizobium phaseoli CE-3 were identified. The two regions were contained in overlapping cosmids pSM927 and pSM991. These cosmids, in a R. phaseoli pSym-cured strain background, induced ineffective nodules on Phaseolus vulgaris roots. Transconjugants of Rhizobium meliloti harbouring pSM991 induced nodule-like structures on bean roots, suggesting that this cosmid contains host-range determinants. Analysis of deletions and insertional mutations in the sequences of pSM991 indicated that the genes responsible for the induction and development of nodules in P. vulgaris are organized in two regions 20 kb apart. One region, located in a 6.8 kb EcoRI fragment, includes the common nodABC genes. The other region, located in a 3.5 kb EcoRI fragment, contains information required for host-range determination.
已鉴定出菜豆根瘤菌CE-3共生质粒（pSym）的两个结瘤区域。这两个区域包含在重叠黏粒pSM927和pSM991中。这些黏粒在菜豆根瘤菌pSym缺失菌株背景下，在菜豆根上诱导形成无效根瘤。携带pSM991的苜蓿根瘤菌转接合子在菜豆根上诱导形成类根瘤结构，表明该黏粒含有宿主范围决定因子。对pSM991序列中的缺失和插入突变分析表明，负责菜豆根瘤诱导和发育的基因分布在两个相距20 kb的区域。一个区域位于一个6.8 kb的EcoRI片段中，包含常见的nodABC基因。另一个区域位于一个3.5 kb的EcoRI片段中，包含宿主范围决定所需的信息。
