Novikova N, Safronova V
Research Institute for Agricultural Microbiology, St. Petersburg, Russia.
FEMS Microbiol Lett. 1992 Jun 15;72(3):261-8. doi: 10.1016/0378-1097(92)90472-z.
It is known that the Rhizobium galegae genomes contain megaplasmids. The suicide vector pSUP2111 with nifH gene of R. meliloti was introduced into the strains CIAM 0703 and CIAM 0711 of R. galegae inducing effective nodules on Galega orientalis plants. The formation of self-transmissible megaplasmids was observed. The megaplasmid transfer into non-nodulating R. meliloti mutants resulted in partial complementation of the nodulation defect in recipient strains though only one transconjugant showed the nitrogen-fixing activity in symbiosis with alfalfa and another one in symbiosis with G. orientalis plants. Among the Agrobacterium strains harbouring R. galegae megaplasmids there were four classes of transconjugants: (1) Nod+ Fix- in symbiosis with goat's rue plants (three strains); (2) Nod+ Fix- on Medicago sativa (two strains); (3) Nod+ Fix+ on M. sativa (five strains); (4) Nod- with both plant hosts (11 strains).
已知盖氏根瘤菌基因组含有大质粒。携带苜蓿根瘤菌nifH基因的自杀载体pSUP2111被导入盖氏根瘤菌的CIAM 0703和CIAM 0711菌株中，这些菌株能在东方山羊豆植株上诱导形成有效根瘤。观察到了自我传递大质粒的形成。大质粒转移到不结瘤的苜蓿根瘤菌突变体中，导致受体菌株的结瘤缺陷部分互补，不过只有一个接合子在与苜蓿共生时表现出固氮活性，另一个在与东方山羊豆植株共生时表现出固氮活性。在携带盖氏根瘤菌大质粒的农杆菌菌株中，有四类接合子：(1) 与山羊豆植株共生时结瘤但不固氮（三株）；(2) 在紫花苜蓿上结瘤但不固氮（两株）；(3) 在紫花苜蓿上结瘤且固氮（五株）；(4) 对两种植物宿主都不结瘤（11株）。
