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Phosphorus, the most essential nutrient for plants, becomes quickly unavailable for the plants in the soil. Phosphate solubilizing bacteria (PSB( can play an important role in providing Phosphorus for plants. In this study, the PSBs were screened from plant rhizosphere by Pikovskaya method. Then, the growth rate and phosphate solubilizing ability of 9 superior strains were measured at different temperatures and levels of salinity and pH. The best strain was identified by 16S rDNA gene sequence analysis. Finally, the genetic diversity of phosphate solubilizing strains were examined by RAPD markers. Results showed that 25 strains were capable of solubilizing insoluble phosphates among the 57 isolates studied. Of the nine superior strains, Cke1 had the highest solubilizing index with the average growth rate under all conditions and was introduced as the best PSB strain identified in the present study. 16S rDNA gene sequence analysis showed that this strain belonged to the Enterobacter genus. The results of genetic variation showed that all stains were divided into six groups and three strains that had the lowest similarity with other strains were placed in three separate groups. Given that Cke1 strain has the ability of solubilizing the insoluble phosphate in different stresses, it can be a good candidate for providing phosphorus at temperatures of 30 and 35 °C, 1.2% and 1.8% salinity levels and pH levels of 6 and 8 for the crops.

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Magentotactic bacteria are the types of bacteria capable of orientation in an external magnetic field because of the ability to produce structures called magnetosomes. Magnetosomes, nanometer-scale structures, are present in most of the magnetotactice bacteria. They are intracellular organelles composed of magnetic iron mineral crystals individually surrounded by a phospholipid layer. Because of the unique features of magnetosomes, magentotactic bacteria have become the fascinating subject of research in many research and applied fields of study, including robotics, medicine, biology, environment and geology. In this review, we have tried to introduce magentotactic bacteria, the formation of magnetosomes and their structures, in order to highlight the importance of these bacteria. Finally, some applications of these bacteria in different areas of research, e.g. targeted drug delivery, cancer treatment and removal of heavy metals from water, were described in order that a better understanding of their applications could be obtained.