Isolation and Antibacterial Properties of Actinomycetes from Yellow Olive Tree (Olea europaea)

The symbiotic relationships between Actinomycetes and their host plants further enhance their potential as sources of bioactive compounds. These bacteria produce a wide array of secondary metabolites with antimicrobial, insecticidal, and anticancer properties, making them valuable for bioprospecting in pharmaceuticals and agriculture.The ineffectiveness of existing antibiotics has resulted in higher morbidity and mortality rates, alongside escalating healthcare costs due to treatment failures. The rise of multidrug-resistant (MDR) pathogens poses a significant threat to global health, necessitating the discovery of novel antimicrobial agents. This study isolates and characterizes endophytic Actinomycetes from the yellow olive tree (Olea europaea), a plant known for its rich phytochemical composition, to evaluate their antibacterial potential against ESKAPE pathogens. Samples were collected from olive tree roots, yielding ۵۴ bacterial isolates, of which ۴۵ (۸۳.۳%) were identified as Actinomycetes through ۱۶S rRNA gene amplification. Among these, ۱۶ isolates (۳۵.۶%) exhibited antibacterial activity against drug-sensitive and drug-resistant strains of Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae.Molecular screening revealed that ۶۶.۷%, ۲۸.۹%, and ۹۳.۳% of the isolates harbored non-ribosomal peptide synthetase (NRPS), polyketide synthase I (PKS-I), and polyketide synthase II (PKS-II) genes, respectively, which are associated with secondary metabolites biosynthesis. However, no direct correlation was found between these biosynthetic genes and antibacterial activity, suggesting that gene expression and environmental factors play crucial roles in metabolite production. The study highlights the potential of endophytic Actinomycetes from Olea europaea as a source of novel antimicrobial compounds, particularly in the fight against MDR pathogens. These findings underscore the importance of exploring plant-associated microbes for developing new therapeutic agents to address the global antibiotic resistance crisis.

کلیدواژه ها:

Endophytic Actinomycetes ، Olea europaea ، Antibacterial activity ، Biosynthetic Gene Clusters ، Secondary metabolites