RESUMO

Pyrolysis mass spectrometry (PyMS) and DNA fingerprinting (RAPD and RSalpha hybridization) were used to characterize soybean inoculant strains and root nodule isolates of bradyrhizobia from the Brazilian Cerrado soils. Most isolates were shown to be derived from the inoculant strains on the basis of genotype comparisons by DNA fingerprinting. Phenotypic analysis (using PyMS) of the strains and separately of the polysaccharides derived from them showed that the nodule isolates differed from the parental strains, suggesting adaptation to the Cerrado soil environment. The extent of the differences between the derivatives and inoculant strains was similar for comparisons made on the basis of whole-cell preparations or from the isolated polysaccharides, indicating that the adaptation was caused by changes in the composition of the polysaccharides produced.

Assuntos

Adaptação Fisiológica , Bradyrhizobium/crescimento & desenvolvimento , Bradyrhizobium/genética , Glycine max/microbiologia , Polissacarídeos Bacterianos/química , Microbiologia do Solo , Bradyrhizobium/química , Brasil , Espectrometria de Massas/métodos , Hibridização de Ácido Nucleico , Polissacarídeos Bacterianos/genética , Polissacarídeos Bacterianos/metabolismo , Técnica de Amplificação ao Acaso de DNA Polimórfico