Genetic diversity of an Italian Rhizobium meliloti population from different Medicago sativa varieties

• Published in: Applied and Environmental Microbiology Vol. 62; no. 7; pp. 2279 - 2285
• Main Authors: Paffetti, D. (Universita degli Studi di Firenze, Florence, Italy.), Scotti, C, Gnocchi, S, Fancelli, S, Bazzicalupo, M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.07.1996
• Subjects: ADN; Analysis of Variance; Bacteria; Bacteriology; Base Sequence; Biological and medical sciences; CHROMOSOME; Chromosome Mapping; Chromosomes, Bacterial - genetics; CROMOSOMAS; DNA Primers - genetics; DNA, Bacterial - genetics; DNA, Ribosomal - genetics; EMILIA ROMAGNA; EMILIE ROMAGNE; Flowers & plants; Fundamental and applied biological sciences. Psychology; GENE; GENES; Genetic Variation; Genetics; Italy; LOMBARDIA; LOMBARDIE; MARCADORES GENETICOS; MARQUEUR GENETIQUE; MEDICAGO SATIVA; Medicago sativa - microbiology; Microbiology; Molecular Sequence Data; Nitrogen; PLASMIDE; PLASMIDIOS; Plasmids - genetics; POLIMORFISMO GENETICO; Polymorphism, Restriction Fragment Length; POLYMORPHISME GENETIQUE; Random Amplified Polymorphic DNA Technique; Regions; RFLP; RHIZOBIUM MELILOTI; RIBOSOMAS; RIBOSOME; RNA, Bacterial - genetics; RNA, Ribosomal, 16S - genetics; RNA, Ribosomal, 23S - genetics; Sinorhizobium meliloti - genetics; Sinorhizobium meliloti - isolation & purification; Soil Microbiology; Soils; Symbiosis; VARIACION GENETICA; VARIATION GENETIQUE; VARIEDADES; VARIETE; Italy; Europe; Symbionte; Rhizobium meliloti; Genetic variability; Genetic marker; Ribosomal DNA; Medicago sativa; Spacer DNA; Plasmid; Restriction fragment length polymorphism; Leguminosae; Random amplified polymorphic DNA; Dicotyledones; Angiospermae; Bacteria; Isolate; Spermatophyta; Rhizobiaceae; Fodder crop; Polymorphism
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/aem.62.7.2279-2285.1996

We investigated the genetic diversity of 96 Rhizobium meliloti strains isolated from nodules of four Medicago sativa varieties from distinct geographic areas and planted in two different northern Italian soils. The 96 isolates, which were phenotypically indistinguishable, were analyzed for DNA polymorphism with the following three methods: (i) a randomly amplified polymorphic DNA (RAPD) method, (ii) a restriction fragment length polymorphism (RFLP) analysis of the 16S-23S ribosomal operon spacer region, and (iii) an RFLP analysis of a 25-kb region of the pSym plasmid containing nod genes. Although the bacteria which were studied constituted a unique genetic population, a considerable level of genetic diversity was found. The new analysis of molecular variance (AMOVA) method was used to estimate the variance among the RAPD patterns. The results indicated that there was significant genetic diversity among strains nodulating different varieties. The AMOVA method was confirmed to be a useful tool for investigating the genetic variation in an intraspecific population. Moreover, the data obtained with the two RFLP methods were consistent with the RAPD results. The genetic diversity of the population was found to reside on the whole bacterial genome, as suggested by the RAPD analysis results, and seemed to be distributed on both the chromosome and plasmid pSym