Fig. (1) Natural interactions in the rhizosphere. (a) symbiotic interactions between plant’s root and Rh/AMF (b) amensalistic interaction between antibiotic-producing rhizobacteria and protozoans (c) parasitic interaction between the bacterium Pasteuria penetrans and root-knots nematode in the rhizosphere. Rh stands for rhizobacteria and AMF stands for arbuscular mycorrhizal fungi.