Bioactivity of endophytic bacteria and yeasts isolated from Thymus

Document Type: Research Paper


1 Plant Protection Department, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran

2 Research Center for Agriculture and Natural Resources, Hamedan, Iran


Endophytes are important resources of bioactive compounds and due to their potential in the
production of secondary metabolites, they are regarded as a potential reservoir of
biotechnological applications. In this study, the bioactivity of bacteria and yeasts endophytes
residing in Thymus sp. was evaluated. During April to October 2011, symptomless and healthy
tissues of Thymus sp. were collected. A total of 23 strains of endophytic bacteria and 6 yeasts
were isolated. The bio-effects of the endophytes were studied on Botrytis cinerea and plant
pathogenic bacteria Xanthomonas arboricola pv. juglandis and Streptomyces scabies and
human pathogens Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC. Growth
inhibition mechanisms of the endophytes against B. cinerea were evaluated and it seems that the
antimicrobial effects of bacterial endophytes are related to the production of protease enzyme,
hydrogen cyanide and volatile compounds. Bacterial strains were identified as Bacillus,
Pseudomonas and Xanthomonas of which Bacillus was the predominant isolate. For the first
time, Bacillus is reported from Thymus eriocalyx, T. lancifolius, T. fallax, T. kotschyanus and T.
vulgaris and Pseudomonas and Xanthomonas as endophytic bacteria from Thymus.


Main Subjects

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