Phosphate solubilization and the enhancement of chickpea growth by new rhizospheric microorganisms Bacillus tequilensis and Trichoderma orientale

Two Trichoderma strains and three Bacillus strains isolated from the rhizosphere of healthy chickpeas in Algeria were assessed for their phosphate solubilizing capacity in vitro as well as their growth effects on seedlings of the chickpea in pot experiments. The microorganisms tested had higher phosphate-solubilizing activities, with the solubilization index ranging from 2.41 to 7.40. The concentration of solubilized phosphate varied from 30.17 to 157.44 ?g/mL. The maximum phosphatesolubilizing activity was observed in the two culture filtrates of Bacillus tequilensis Bt1 (157.44 ?g/mL) and Trichoderma orientale T1 (143.33 ?g/mL), accompanied by a decrease in pH of the growth medium from 4.51 to 5.75. The application of the strains (B. tequilensis Bt1 and T. orientale T1) separately and in combination had a beneficial effect on germination by promoting the development of the seeds and effectively enhancing plant growth. Chickpea seedlings showed better vegetative growth when treated with a mixture of B. tequilensis Bt1 and T. orientale T1 together than an individual treatment. To our knowledge, this is the first report of the phosphate-solubilizing potential of the combined microorganisms B. tequilensis and T. orientale and their capacity to promote plant growth in chickpeas.