PESTICIDE RESISTANCE AND PHOSPHATASE ACTIVITY OF PHOSPHATESOLUBILIZING BACTERIA IN ACIDIC SOIL

Phosphorus (P) is an essential macronutrient for plant growth, but its availability in soil is frequently limited by chemical fixation and conversion into poorly soluble mineral and organic forms. The problem is particularly important in acidic soils, where phosphorus is strongly associated with iron and aluminium compounds. Soil microorganisms, especially phosphate-solubilizing bacteria (PSB), contribute to phosphorus cycling by dissolving inorganic phosphate minerals and mineralizing organic phosphorus through phosphatase enzymes. At the same time, agricultural soils may receive repeated pesticide applications that can affect non-target microbial populations and their metabolic activities. Consequently, the selection of phosphate-solubilizing bacteria capable of tolerating pesticide exposure while retaining phosphorus-mobilizing functions has potential importance for sustainable agriculture. The present research paper examines the relationship between pesticide tolerance, phosphate solubilization and phosphatase activity of phosphatesolubilizing bacteria associated with acidic soil. The proposed methodology involves isolation of phosphate-solubilizing bacteria from acidic agricultural soil, qualitative and quantitative phosphate-solubilization assays, pesticide-tolerance screening, acid and alkaline phosphatase assays, biochemical characterization. The acid phosphatase activity harbouring bacterial communities can be particularly important in acidic soils, while pesticide tolerance varies substantially among bacterial isolates. The model results presented in this paper demonstrate how multifunctional isolates could be identified based on simultaneous pesticide tolerance, phosphate-solubilizing efficiency and phosphatase activity. Such isolates may have potential as microbial inoculants for phosphorus-deficient acidic soils subjected to pesticide management.