Molecular characterization of a salt-tolerant bacterial community in the rice rhizosphere.

The diversity of salt-tolerant bacteria present in the rhizosphere of Oryza sativa was investigated. Fourteen bacterial strains, isolated after enrichment in nitrogen-free, semi-solid medium and showing tolerance to 3% NaCl, were analyzed by restriction patterns produced by amplified DNA coding for 16S rDNA (ARDRA) with enzymes Sau3AI, AluI and RsaI which showed that they were represented by 4 ARDRA types. Biodiversity among the 14 strains was also analyzed by the random amplified polymorphic DNA (RAPD) technique with a 10-mer primer. Partial nucleotide sequence of 16S rDNA assigned these clusters to Serratia marcescens, Pseudomonas aeruginosa, Alcaligenes xylosoxidans and Ochrobactrum anthropi. Notably, all four bacterial species are potential human pathogens that infect immunocompromised patients.