Phosphate-Solubilizing Bacterium Acinetobacter pittii gp-1 Affects Rhizosphere Bacterial Community to Alleviate Soil Phosphorus Limitation for Growth of Soybean (Glycine max)

Abstract

Phosphorus (P) availability is a major restriction to crop production, and phosphate-solubilizing bacteria (PSBs) in soils are responsible for P turnover. However, it remains unknown whether the application of PSB can facilitate both inorganic and organic P transformation and enhance function of plant rhizosphere bacteria. In this study, we applied Illumina MiSeq sequencing, plate-colony counting, quantitative PCR, and multiple ecological analyses. We found that the inoculation of PSB <i>Acinetobacter pittii</i> gp-1 significantly promoted the growth of soybean represented by better vegetation properties (e.g., plant height and root P) and increased activities of phosphatase (4.20-9.72 μg/g/h) and phytase (0.69-1.53 μmol/g/day) as well as content of indole acetic acid (5.80-40.35 μg/g/h). Additionally, the application of strain <i>A. pittii</i> gp-1 significantly increased abundances of both inorganic and organic P-cycling-related genes (i.e., <i>phoD</i>, <i>bpp</i>, <i>gcd</i>, and <i>pstS</i>). More importantly, the application of <i>A. pittii</i> gp-1 could increase the function represented by P-cycling-related enzymes (e.g., phosphotransferase) of rhizosphere bacterial community based on functional profiling. To our knowledge, this is the first report that the application of PSB <i>A. pittii</i> promotes inorganic and organic P utilization and increases the function of rhizosphere bacterial community. Therefore, the PSB <i>A. pittii</i> gp-1 could be a good candidate for the promotion of soybean growth.