Sidrophore Production and Phosphate Solubilization by Bacillus cereus and Pseudomonas fluorescens Isolated from Iraqi Soils and Soil Characterization

Abstract

This study was conducted to explore the ability of Pseudomonas fluorescens and Bacillus cereus to solubilizing a phosphate in soil for enhancing the planting growth and, its relation with soill characterization. The isolates were identified as P.fluorescens and B. cereus using convential analysis and, its phosphate solubilization ability and sidrophore was shown by the clear zone formation on National Botanical Research Institute’s Phosphate medium. Moreover, Pseudomonas fluorescens isolates (n = 9) and three of B. cereus isolated from agricultural area in Baghdad university, Mustansiriyah university and Diyala bridge. Results displayed that bacterial count were varied in soil samples according to their region,,and ranging from 30 to 60 *10 2 CFU/g in Baghdad university soil to 10—20 *10 2 CFU/g in Mustansiriyah university soil ,.,the Baghdad soil macronutrient which included: NH4 , NO3 ,P,and K were ., 8.42 , 20.53 , 19.09 218.73 respectively, While the physio analysis revealed that the mean of pH was 7.3 and EC was 8.63. on the other hand the micronutrient analysis indicated that the soil samples were included Ca ,Fe ,Mn ,Zn and Cu which gave their mean 5025.9 , 8.9, 4.9, 0.5 and 1.5 respectevily. Results revealed that all isolated bacteria (9 isolates of P.fluorescens and three isolates of B. cereus gave ahalo zone which mean their ability to be phosphate solubilizing bacteria at 100%. Results revealed that all isolated bacteria were detected a ability to produce high levels from chelating agents(( siderophores)) by P.fluorescens and. B cereus at 100%,when appeared ahalo clear zone. Furthermore, the high levels of phosphate solubilization and siderophore production were grouped in bacterial species isolated from Iraqi soils. might be attributed to many soil factors such as soil nutrient status, soil acidity, water content, organic matter and soil enzyme activities.