Isolation and Characterization of Plant Growth Promoting Bacteria from Contaminated Soil and their Impact on Triticum Aestivum

Abstract

Plant growth promoting bacteria (PGPB) or plant growth promoting rhizobacteria (PGPR) are bacteria that exist in the rhizospheres of plant soil and form symbiotic relationships with the plant.Some of the methods through which PGPR aid in plant growth is by playing a role in nitrogen fixation, phosphate solubilization, iron chelation, reduction of heavy metal uptake by plant, reducing spread of plant diseases, secretion of phytohormones, significantly influencing root morphology and growth and by increasing the bio-availability of nutrients in the soil. One way to develop methods to cultivate this crop by using sustainable methods that can also increase the quality and yield of this crop is by treating the seeds of this plant with PGPB. In this study we examined the potential impact of bacteria, isolated from contaminated soil, on plant development and growth promotion. Our study aimed to isolate and characterize these bacteria and, after treatment of the seeds of Triticum aestivum with each of the bacterial isolates, test their ability to positively influence the growth of Triticum aestivum. After isolation and purification of the bacterial strains via quadrant streaking, we performed microscopic analysis and biochemical tests on the bacterial isolates which were thus identified to be Escherichia coli, Staphylococcus aureus and Pseudomonas spp. We compared the growth of the seeds treated with each bacterial isolate with that of the control. The parameters that were taken into account and compared were root and stem length and the number of leaves, branches and roots. E.coli increased the steam and root length of wheat whereas, S.aureus increased the number of branches but it decreased the root length. While Pseudomonas spp. increased the stem and root length and increased the number of branches. Hence, Pseudomonas spp. was the most effective boosting more aspects of wheat growth in comparison to E.coli and S.aureus.