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Mechanism of insoluble phosphate solubilization by Pseudomonas fluorescens RAF15 isolated from ginseng rhizosphere and its plant growth‐promoting activities
Author(s) -
Park K.H.,
Lee C.Y.,
Son H.J.
Publication year - 2009
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.2009.02642.x
Subject(s) - rhizosphere , pseudomonas fluorescens , solubilization , phosphate , plant growth , phosphate solubilizing bacteria , rhizobacteria , pseudomonas , ginseng , biology , pseudomonadaceae , pseudomonadales , botany , bacteria , chemistry , biochemistry , genetics , medicine , alternative medicine , pathology
Aims: To investigate the mechanism of insoluble phosphate (P) solubilization and plant growth‐promoting activity by Pseudomonas fluorescens RAF15. Methods and Results: We investigated the ability of Ps. fluorescens RAF15 to solubilize insoluble P via two possible mechanisms: proton excretion by ammonium assimilation and organic acid production. There were no clear differences in pH and P solubilization between glucose‐ammonium and glucose‐nitrate media. P solubilization was significantly promoted with glucose compared to fructose. Regardless of nitrogen sources used, Ps. fluorescens RAF15 solubilized little insoluble P with fructose. High performance liquid chromatography analysis showed that Ps. fluorescens RAF15 produced mainly gluconic and tartaric acids with small amounts of 2‐ketogluconic, formic and acetic acids. During the culture, the pH was reduced with increase in gluconic acid concentration and was inversely correlated with soluble P concentration. Ps. fluorescens RAF1 showed the properties related to plant growth promotion: pectinase, protease, lipase, siderophore, hydrogen cyanide, and indoleacetic acid. Conclusion: This study indicated that the P solubility was directly correlated with the organic acids produced. Significance and Impact of the Study: Pseudomonas fluorescens RAF15 possessed different traits related to plant growth promotion. Therefore, Ps. fluorescens RAF15 could be a potential candidate for the development of biofertilizer or biocontrol agent.