Identification of nodule-dominant Rhizobium meliloti strains carrying pRmeGR4b-type plasmid within indigenous soil populations by PCR using primers derived from specific DNA sequences |
| |
| Authors: | Pablo J Villadas Encarna Velazquez Eustoquio Martinez-Molina Nicolas Toro |
| |
| Institution: | Departamento de Microbiología, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;Departamento de Microbiología y Genética, Universidad de Salamanca, Avda. Campo Charro s/n, 37007 Salamanca, Spain |
| |
| Abstract: | Abstract: Rhizobium meliloti strain GR4 is a highly infective and competitive bacteria which was isolated in 1975 from a field site in Granada (Spain) and which has a high potential as an inoculant. R. meliloti isolates from alfalfa plants grown in this field site were characterized using polymerase chain reaction. Characterization was based on primers derived from insertion sequence elements (IS Rm3 and IS Rm4 ), plasmid origin of replication (pRmeGR4a repC locus) and plasmid pRmeGR4b specific DNA sequences. Soil isolates harbouring plasmid type pRmeGR4b represented the major infective population in this field site. A direct correlation between the presence of pRmeGR4b-like plasmid and the competitiveness of the strains was found. In addition, four different R. meliloti field populations isolated from Spanish soils were analyzed for the presence of pRmeGR4b related plasmids. Our results indicate that this plasmid type is widespread among R. meliloti field populations and that its frequency within the infective isolates depends on the host plant. |
| |
| Keywords: | Rhizobium meliloti Competitiveness Polymerase chain reaction IS fingerprinting |
|
|
