The Impact of the Inoculation of Phosphate-Solubilizing Bacteria Pantoea agglomerans on Phosphorus Availability and Bacterial Community Dynamics of a Semi-Arid Soil

• Published in: Microorganisms (Basel) Vol. 9; no. 8; p. 1661
• Main Authors: Saadouli, Ilhem, Mosbah, Amor, Ferjani, Raoudha, Stathopoulou, Panagiota, Galiatsatos, Ioannis, Asimakis, Elias, Marasco, Ramona, Daffonchio, Daniele, Tsiamis, George, Ouzari, Hadda-Imene
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.08.2021; MDPI
• Subjects: Abundance; Acidification; Acids; Agricultural production; Agriculture; Aridity; Availability; available P; Bacilli; Bacteria; Biofertilizers; Biosynthesis; Calcium phosphates; Community composition; Community structure; Composition; Correlation analysis; Dehydrogenases; Environmental conditions; Fertilizers; Gene expression; Genes; Genotype & phenotype; Gluconic acid; Glucose; high-throughput sequencing; Incubation; Inoculation; Inoculum; Metagenomics; microbial inoculants; Next-generation sequencing; Pantoea agglomerans; pH effects; Phenotypes; Phosphates; Phosphorus; Phylogenetics; Polyethylene glycol; Relative abundance; rRNA 16S; Soil analysis; soil bacterial community composition; soil bacterial community structure; Soil characteristics; Soil conditions; Soil dynamics; Soil microorganisms; Soil structure; Soils; Solubilization; Tricalcium phosphate; Tunisia; soil bacterial community composition; available P; microbial inoculants; soil bacterial community structure; high-throughput sequencing
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms9081661

The bacterial genus has been widely evaluated as promising bacteria to increase phosphorus (P) availability in soil. The aim of this study was to characterize the phosphate solubilizing (PS) activity of a strain and to evaluate the impact of its application in a semi-arid soil on phosphate availability and structure of the bacterial communities as a whole. An incubation experiment under close-to-natural soil environmental conditions was conducted for 15 days at 30 °C. High-throughput sequencing of the bacterial 16S rRNA gene was used to characterize and to compare the bacterial community structure of -inoculated soil with non-inoculated control. Furthermore, a qPCR-based method was developed for detection and quantification of the functional genes related to the expression of mineral phosphate solubilization (MPS) phenotype in . The results showed that in vitro solubilization of Ca (PO ) by strain was very efficient (980 mg/L), and it was associated with a drop in pH due to the secretion of gluconic acid; these changes were concomitant with the detection of and genes. Moreover, inoculum application significantly increased the content of available P in semi-arid soil by 69%. Metagenomic analyses showed that treatment modified the overall edaphic bacterial community, significantly impacting its structure and composition. In particular, during inoculation the relative abundance of bacteria belonging to Firmicutes (mainly class) significantly increased, whereas the abundance of Actinobacteria together with Acidobacteria and Chloroflexi phyla decreased. Furthermore, genera known for their phosphate solubilizing activity, such as , , , and were exclusively detected in -treated soil. Pearson's correlation analysis revealed that changes in soil bacterial community composition were closely affected by soil characteristics, such as pH and available P. This study explores the effect of the inoculation of on the bacterial community structure of a semi-arid soil. The effectiveness in improving the phosphate availability and modification in soil bacterial community suggested that represent a promising environmental-friendly biofertilizer in arid and semi-arid ecosystems.