The properties of rhizobacteria from tomato rhizosphere as biocontrol and biofertilizer

Abstract Low soil fertility and the presence of pathogen are the limiting factors in horticultural crops cultivation in Ambon City. This study aimed to isolate plant growth promoting rhizobacteria from tomato rhizosphere as a potential biocontrol, biostimulant and biofertilizer. The research consisted of two stages, namely (1) isolation of bacteria from tomato rhizosphere and purification of the isolates, and (2) characterization of colony morphology, gram reaction, hypersensitivity test and antagonist test to soil pathogens, phosphate dissolution, and phytohormones indole acetic acid (IAA) production. Forty-two isolates were found from tomato rhizosfer, 36 isolates suppressed growth of Rhizoctonia solani while 6 isolates increased the growth of those pathogen. The growth of Phytophthora sp. pathogen was decreased by 35 bacterial isolates and increased by 7 bacterial isolates. All isolates produce IAA but only 13 isolates are enabled to dissolve inorganic phosphate. Based on bacterial properties, the isolates of TT-22, TT-21, TT-12, TT-11, WT-11 and WT-332 are the promising isolates for developing the biological agent as pathogen control and biofertilizer.