AUTHOR=Teles E. A. P. , Xavier J. F. , Arcênio F. S. , Amaya R. L. , Gonçalves J. V. S. , Rouws L. F. M. , Zonta E. , Coelho I. S. 

TITLE=Characterization and evaluation of potential halotolerant phosphate solubilizing bacteria from Salicornia fruticosa rhizosphere

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1324056

DOI=10.3389/fpls.2023.1324056

ISSN=1664-462X

ABSTRACT=<p>Soil salinization is a significant abiotic factor threatening agricultural production, while the low availability of phosphorus (P) in plants is another worldwide limitation. Approximately 95–99% of the P in soil is unavailable to plants. Phosphate-solubilizing bacteria (PSB) transform insoluble phosphates into soluble forms that plants can utilize. The application of PSB can replace or partially reduce the use of P fertilizers. Therefore, selecting bacteria with high solubilization capacity from extreme environments, such as saline soils, becomes crucial. This study aimed to identify twenty-nine bacterial strains from the rhizosphere of <italic>Salicornia fruticosa</italic> by sequencing the 16S rDNA gene, evaluate their development in increasing concentrations of NaCl, classify them according to their salinity response, and determine their P solubilization capability. The bacteria were cultivated in nutrient agar medium with NaCl concentrations ranging from 0.5% to 30%. The phosphate solubilization capacity of the bacteria was evaluated in angar and broth National Botanical Research Institute (NBRIP) media supplemented with calcium phosphate (CaHPO<sub>4</sub>) and aluminum phosphate (AlPO<sub>4</sub>), and increased with 3% NaCl. All bacterial strains were classified as halotolerant and identified to the genera <italic>Bacillus</italic>, <italic>Enterobacter</italic>, <italic>Halomonas</italic>, <italic>Kushneria</italic>, <italic>Oceanobacillus</italic>, <italic>Pantoea</italic>, <italic>Pseudomonas</italic>, and <italic>Staphylococcus</italic>, with only one isolate was not identified. The isolates with the highest ability to solubilize phosphorus from CaHPO<sub>4</sub> in the liquid medium were <italic>Kushneria</italic> sp. (SS102) and <italic>Enterobacter</italic> sp. (SS186), with 989.53 and 956.37 mg·Kg<sup>-1</sup> P content and final pH of 4.1 and 3.9, respectively. For the solubilization of AlPO<sub>4</sub>, the most effective isolates were <italic>Bacillus</italic> sp. (SS89) and <italic>Oceanobacillus</italic> sp. (SS94), which raised soluble P by 61.10 and 45.82 mg·Kg<sup>-1</sup> and final pH of 2.9 and 3.6, respectively. These bacteria demonstrated promising results in <italic>in vitro</italic> P solubilization and can present potential for the development of bioinput. Further analyses, involving different phosphate sources and the composition of produced organic acids, will be conducted to contribute to a comprehensive understanding of their applications in sustainable agriculture.</p>