Phosphate solubilization potential and modeling of stress tolerance of rhizobacteria from rice paddy soil in northern Iran

• Published in: World journal of microbiology & biotechnology 2014-09, Vol.30 (9), p.2437-2447
• Main Authors: Bakhshandeh, Esmaeil, Rahimian, Heshmatollah, Pirdashti, Hematollah, Nematzadeh, Ghorban Ali
• Format: Article
• Language: English
• Subjects: Acetic acid; Acidity; Agricultural biotechnology; Agronomy; Applied Microbiology; Bacteria; Bacteria - classification; Bacteria - drug effects; Bacteria - metabolism; Bacteria - radiation effects; Biochemistry; Biomedical and Life Sciences; Biotechnology; Cell division; Cluster Analysis; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; Enterobacter; Environmental Engineering/Biotechnology; Environmental impact; Fertilizers; Hydrogen-Ion Concentration; Indoleacetic Acids - metabolism; Iran; Life Sciences; Microbiology; Microorganisms; Molecular Sequence Data; Natural resources; Original Paper; Oryza - growth & development; Oryza sativa; Phosphates; Phosphates - metabolism; Phylogeny; Plant diseases; Plant growth; Productivity; Rahnella aquatilis; Rhizosphere; Rice; Rice fields; RNA, Ribosomal, 16S - genetics; Sequence Analysis, DNA; Sequencing; Sodium chloride; Sodium Chloride - metabolism; Soil (material); Soil Microbiology; Solubilization; Stress response; Studies; Temperature; Tolerances
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-014-1669-1

The purposes of this study were to evaluate the phosphate solubilization activity of bacteria isolated from the rhizosphere of rice paddy soil in northern Iran, and to study the effect of temperature, NaCl and pH on the growth of these isolates by modeling. Three of the most effective strains from a total of 300 isolates were identified and a phylogenetic analysis was carried out by 16S rDNA sequencing. The isolates were identified as Pantoea ananatis (M36), Rahnella aquatilis (M100) and Enterobacter sp. (M183). These isolates showed multiple plant growth-promoting attributes such as phosphate solubilization activity and indole-3-acetic acid (IAA) production. The M36, M100 and M183 isolates were able to solubilize 172, 263 and 254 µg ml −1 of Ca 3 (PO 4 ) 2 after 5 days of growth at 28 °C and pH 7.5, and to produce 8.0, 2.0 and 3.0 μg ml −1 of IAA when supplemented with l -tryptophan (1 mg ml −1 ) for 72 h, at 28 °C and pH 7.0, respectively. The solubilization of insoluble phosphate was associated with a drop in the pH of the culture medium and there was an inverse relationship between pH and solubilized P ( r  = −0.98, P