Molecular Characterization and Antimicrobial Activity of Actinomycetes Isolated from Rhizosphere Soil

Author: Jakke Kiranmai, Nagaraju Alpula and Podeti Srinivas

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Abstract

Strains of Actinomycetes are isolated from soil samples obtained at different places, including Karimnagar and Warangal in Telangana. Chili plant rhizosphere soil samples were serially diluted and plated on starch-casein media for one to two weeks at 37°C. Using morphological, biochemical, and cultural characterization, the isolated cultures were studied for their morphology, substrate mycelial growth, and enzyme degradation. The experiments were conducted in compliance with the International Streptomyces Project (ISP). The strains KNR-1 and WGL-1 were characterized by biochemical procedures such as morphological, cultural, and 16S rRNA gene sequencing. Following characterization, the cultures were identified using 16S rDNA gene sequencing. Streptomyces broussonetiae KNR-1 (Accession No.OQ421513) and Nocardioides sp. WGL-1 (Accession No.OQ421515). Based on their appearance, the isolates were evaluated for antibacterial efficacy against pathogens. Antimicrobial activity was assessed in five clinical isolates. WGL-1 exhibited the highest antibacterial activity against Escherichia coli ANRPS-P5 (Accession No.OQ151987), Staphylococcus aureus ANRPS-P4 (Accession No.OQ151986), Pseudomonas aeruginosa ANRPS-P3 (Accession No.OQ151984), Salmonella enterica strain -P2(Accession No.OQ151982), and Klebsiella pneumoniae strain -P1 (Accession No OQ151981) while KNR-1 had the lowest. These isolated strains had antibacterial activity and could potentially be used in the research and development of novel antibiotics for use in the pharmaceutical or agricultural industries.

Keywords

Actinomycetes, Characterization, 16S rDNA, Antimicrobial activity

Conclusion

The KNR-1 and WGL-1 Actinomycetes that have been obtained were isolated from the indigenous flora of soil resources by utilizing starch casein agar, which is used for isolating bacteria, and Actinomycetes isolation agar medium, which is used for isolating yeast. This resulted in smooth, leathery, matte colonies that were cultivated using the spread plate method. When a soil sample taken from the chili rhizosphere is heated, the formation of Actinomycetes is enhanced while the growth of other organisms is inhibited. In addition, the fertility of the soil provides evidence that actinomycetes are present. Actinomycetes are well-known for their ability to produce soluble inorganic materials via the breakdown of chemical compounds that originate from organic forms. This process occurs when Actinomycetes feed on organic matter. Isolate yields were all over the place, despite the fact that KNR-1 and WGL-1 showed dominating growth with better sporulation. From the rhizopheric soil of chilli plants, Streptomyces broussonetiae and Nocardioides sp. were able to be isolated, and their cultural, morphological, and biochemical characteristics were investigated. The KNR-1 and WGL-1 Actinomycetes isolate shown antibacterial activity against Klebsiella pneumonia, Salmonella enterica, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia. However, these Actinomycetes isolates had a lower level of activity against Klebsiella pneumoniae in comparison to other test pathogens. The collected DNA was used as a template in PCR reactions, and the 16S rDNA gene was sequenced to identify the various isolates. The size of the Streptomyces broussonetiae amiplicons was 1500 base pairs, while the size of the Nocardioides sp. amiplicons was also 1500 base pairs. Actinomycetes are the genus from which the isolates KNR-1 and WGL-1 originate. These isolates have antibacterial activity and can be used in the research and development of novel antibiotics for either the pharmaceutical or agriculture industries.

References

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How to cite this article

Jakke Kiranmai, Nagaraju Alpula and Podeti Srinivas (2023). Molecular Characterization and Antimicrobial Activity of Actinomycetes Isolated from Rhizosphere Soil. Biological Forum – An International Journal, 15(5): 1713-1722.