Abstract

• Microorganisms in soil play a crucial role in crop production and sustainable development of agriculture. This study was intended to isolate the PGPB strains from different soil sample. The experiment was performed at the Molecular Research Laboratory, Department of Botany, Center for Research and Innovation, University of Yangon, in 2024. In this study, five bacterial strains have been isolated and given named as SP1 to SP5. In morphological characterization, all strains showed the circular shape, entire margin, raised elevation, smooth texture and transparent opacity except the opaque opacity in the strain SP1. Microscopical observations revealed that strains SP1, SP2, SP4 and S5 are bacilli shape, Gram positive bacteria and only SP3 are Gram-negative bacteria with the form of bacilli. The different biochemical tests and nitrogen fixation test of each isolated strains were performed. The DNA extraction and purification from each strain were conducted and all extracted bacterial DNA produce relatively high purity of DNA, ranging between 1.8 and 2.0 in A260/A280 ratio with less impurities in A260/A230 ratio. Among five strains, strain SP2 and SP5 indicated the best DNA purity result. Moreover, the improvement of plant growth promotion performance indicated the positive effects on the selected plants at 15 days post inoculation, especially strains SP2 and SP5 showed the maximum results on plant growth parameters.