Siderophores and indole-3- acetic acid production by bacterial strains isolated from soybean rhizosphere

Rhizobacteria with siderophores and IAA-producing ability may be useful in growth promotion of crop plants or in growth suppression of weeds. Considering the benefits of intensive agriculture practice and the negative environmental impact of chemical fertilizers and pesticides, usage of rhizobacteria as biofertilizers is one of the most promising biotechnologies. Therefore, the present study was performed in order to select several bacterial strains isolated from soybean rhizosphere and rizoplane with siderophores and IAA producing capabilities. Our results showed that soybean rhizosphere represent a very important source for isolation of bacteria with plant growth promoting capabilities. The majority of these microorganisms live in the soil surrounding the roots, but it can be also found in the rizoplane. Many of the isolated rhizobacteria present both siderophores and IAA producing capabilities, proving that the promoting plant growth effect is the result of synergic relations established between different rhizospheric microorganisms.