| Summary: | Phosphate is the second most essential nutrient for plant growth and development. Although the soil contains abundant phosphorus, only 0.1% is used by plant roots due to the significant amount of calcium carbonate (CaCO3) present in the calcareous soil, which limits the availability of P by reacting calcium ions with phosphate ions. It leads to alkaline reactions by generating insoluble phosphate compounds such as tricalcium phosphate. Here we study to boost phosphate solubilization in PSMs as an alternate strategy. Twenty-one bacterial isolates were selected from two different crops and investigated in vitro for their plant growth potential. All bacteria show capacity for phosphate solubility by producing a clear halo zone beneath and much more around bacterial colonies on Pikovskaya agar. In contrast, on modified Pikovskaya and only seven isolates with 60% reduction in zone formation were revealed to be positive for phosphate solubilization in which SWC5 was the best phosphate solubilizers with 1.25 phosphate solubilization index, respectively. All phosphate solubilizing bacteria showed irregular pattern in lowering the pH ranging from 4.1-6.27, where maximum decreased in pH was shown by SWS10.All bacteria showed phosphate solubilization ability in Pikovskaya broth phosphomolybdate assay ranging from 6.31 to 20.9 μg ml−1 in which the highest efficiency was demonstrated by SWS10. Phosphate solubilization efficiency in the potential isolates was confirmed by the presence of PqqE gene. The presence of the pqqE gene which is involved in phosphate solubilization was found in SWC4, SWC5, SWS10, and SW14 and it was absent in SWS9, SW18, and SW21. All the bacterial isolates were phylogenetically identified by sequencing and analyzing the 16S rRNA gene. The potential isolates Pseudomonas Koreensis, Pantoea dispersa, Pseudomonas sp., Agrobacterium sp. and consortia were selected for controlled condition experiment on Triticum aestivum. The highest plant dry weight was achieved by application of consortia and Pseudomonas Koreensis by increasing 65% and 59%, respectively, compared to control. © 2024, ALÖKI Kft., Budapest, Hungary.
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