Isolation of Inorganic Phosphorus-Solubilizing Bacteria from the Rhizosphere of Festuca arundinacea Schreb.

Abstract

Inorganic phosphorus-solubilizing bacteria promote plant growth. However, different strains have different effects. The objective of this study was to screen efficient inorganic phosphorus-solubilizing bacteria (iPSB) from the rhizosphere of Festuca arundinacea Schreb. using Pikovskaya (PVK) medium. The results showed that 43 iPSB isolates were screened by clear halo zone production on PVK medium. Among them, the phosphate solubilization index (PSI) on the PVK medium of 31 iPSBs was calculated to be more than 1.5 at 28 °C in 7 days and ranged from 1.52 to 2.63. The best 31 iPSB isolates were selected for further study, including molecular identification using the 16S rRNA gene, testing of their P solubilization capacity in PVK broth medium, and the detection of catalase activity and organic acid and siderophore production. Among the 31 isolates, the phosphate solubilization of 8 isolates ranged from 203.96 to 412.22 µg/mL, and the value was significantly larger than that of the PVK broth medium without any bacterial isolates. These isolates were identified and belonged to Acinetobacter calcoaceticus, Buttiauxella sp., and Erwinia piriflorinigrans by sequence analysis of the 16S rRNA gene. These iPSB bacterial isolates enrich plant growth-promoting rhizobacteria and can promote the development of sustainable agriculture as phosphate fertilizer synergists.