Isolation, plant growth-promoting traits, antagonistic effects on clinical and plant pathogenic organisms and identification of actinomycetes from olive rhizosphere

Abstract

Soil actinomycetes are a highly common group of bacteria and frequently studied as having secondary metabolites in the potential of producing the most preferred antagonistic content. Considering the continuous variation in soil structure, there is a potential for encountering different organisms. Almost all of antibiotic contents are produced by these bacteria and their importance increase. In this study, eleven different actinomycetes strain were isolated from the rhizosphere of olive trees investigated for their plant growth-promoting (PGP) traits including ammonia production, indole-3-acetic acid production, phosphate solubilization, and siderophore production with antagonistic activities against a set of pathogenic bacteria, fungi, and yeasts. All actinomycetes were identified according to 16S rRNA regions were recognized in four different Streptomyces species but according to fatty acid analysis, there would be at least six different organisms. The potential for antagonistic and plant growth-promoting traits of olive tree rhizosphere actinomycetes were a promising tool for agricultural applications and clinical antibiotic resistance. Differentiation of organisms with the antagonism of pathogenic activities and PGP features could be a definitive method for future studies.

Keywords: 16S rRNA; Antagonistic effect; Antibacterial activity; Antifungal activity; Fatty acid analysis; Plant growth-promoting actinomycetes (PGPA).