Phosphate solubilization potential and stress tolerance of rhizobacteria from rice soil in Northern Thailand

• Published in: World journal of microbiology & biotechnology Vol. 25; no. 2; pp. 305 - 314
• Main Authors: Chaiharn, Mathurot, Lumyong, Saisamorn
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.02.2009; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: Acinetobacter; Agricultural production; Aluminum; aluminum phosphate; Ammonia; Applied Microbiology; Bacteria; beta-glucanase; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Calcium phosphates; Catalase; Cellulase; chitinase; endo-1,4-beta-glucanase; Environmental Engineering/Biotechnology; Enzymatic activity; enzyme activity; Enzymes; Fertilizers; Freshwater; Fundamental and applied biological sciences. Psychology; Life Sciences; Microbiology; Microorganisms; Mineralization; Nutrients; Original Paper; Phosphates; Phosphorus; Plant growth; plant growth-promoting rhizobacteria; Plants (organisms); rhizosphere bacteria; Rice; rice soils; Sodium chloride; Soil contaminants; Solubilization; Spectrophotometry; Strain; Stress measurement; stress tolerance; Studies; Thailand; tricalcium phosphate; Thailand; Asia; Plant growth-promoting rhizobacteria; ); Phosphate-solubilizing bacteria; Cell wall-degrading enzyme; Rice; Phosphates; Monocotyledones; Plant growth-promoting rhizobacteria . Phosphate-solubilizing bacteria . Rice (Oryza sativa); Enzyme; Tolerance; Solubilization; Cell wall; Stress; Degradation; Oryza sativa; Soils; Gramineae; Angiospermae; Bacteria; Spermatophyta; Plant growth promoting rhizobacteria
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-008-9892-2

Plant growth-promoting rhizobacteria (PGPR) are known to influence plant growth by various direct or indirect mechanisms. A total of 216 phosphate-solubilizing bacterial isolates were isolated from different rice rhizospheric soil in Northern Thailand. These isolate were screened in vitro for their plant growth-promoting activities such as solubilization of inorganic phosphate, ammonia (NH₃), catalase and cell wall-degrading enzyme activity. It was found that 100% solubilized inorganic phosphate, 77.77% produced NH₃ and most of the isolates were positive for catalase. In addition, some strains also produced cell wall-degrading enzymes such as protease (7%), chitinase (1%), cellulase (3%) and β-glucanase (3%), as evidenced by phenotypic biochemical test and quantitative assay using spectrophotometry. The isolates could exhibit more than two or three plant growth-promoting (PGP) traits, which may promote plant growth directly or indirectly or synergistically. Part of this study focused on the effect of NaCl, temperature, and pH on a specific the bacterial isolate Acinetobacter CR 1.8. Strain CR 1.8 was able to grow on up to 25% NaCl, between 25 and 55°C, and at pH 5-9. Maximum solubilization of tricalcium phosphate and aluminium phosphate was obtained at neutral pH, and 37°C. Strain CR 1.8 had protease activity but no cellulase, β-glucanase and cellulase activities.