The study of inorganic insoluble phosphate solubilization and other plant growth promoting characteristics of indigenous Pseudomonas fluorescens bacteria of Kordan and Gonbad regions

Abstract This study investigated inorganic phosphate solubilization ability of Pseudomonas fluorescens bacteria isolated from Gonbad and Kordan regions as well as some of the plant growth promoting characteristics of the superior phosphate solubilizing isolates. In this study, 58 strains of Pseudomonas fluorescens bacteria were isolated from the soil and evaluated in term of phosphate solubilization ability. Among these 58 isolates, 10 strains showed the most inorganic phosphate solubilization ability. The results showed that there is a 5% level of significant difference from the point of inorganic phosphate solubilization ability. Plant growth promoting characteristics including ACC-deaminase, Auxin and siderophore production ability was studied as well and the results showed that among these ten superior strains, isolate 12, 26 and 42 in spite of having the most ability to solubilize inorganic phosphate, had more significant superiority than other strains in term of studied plant growth promoting characteristics. Totally among these 58 bacterial isolates, 84% were able to solubilize inorganic phosphate and 16% were unable. Furthermore, 70%, 100% and 80 % of the superior phosphate solubilizing bacteria respectively showed the ability to produce siderophore, Auxin and ACC-deaminase enzyme. According to the results, there is no correlation between the ability of strains to solubilize the phosphates, produce IAA, siderophore and ACC-deaminase enzyme. Altogether the bacteria isolated from Kordan soil were more able than Gonbad soil.