Biodiversity of Actinobacteria Isolated from Marmara and Avşa Islands in Türkiye

The main purpose of this study is to investigate the microbial diversity of Actinobacteria, living in soils in the “Marmara” and “Avşa” Islands and to identify species at genus level based on 16S rRNA gene sequences. These islands are located in the southwest of the Sea of Marmara and in the literature review, no Actinobacteria biodiversity studies related to Marmara and Avşa Islands were found. Such unexplored ecological habitats are potentially rich source for discovery sources of novel species and bioactive molecule. Actinobacteria play an important role in many natural phenomena such as nitrogen fixation, roles of these prokaryotic microorganisms. In this article, we focused on the presence and the diversity of Actinobacteria on the Islands by examining multiple sampling sites and using different selective isolation media. A total of 400 culturable Actinobacteria were isolated using ten different isolation media by dilution-plating method. Among the 400 isolates, 112 isolates were selected according to their morphology in different culture media. The isolates were characterized on the basis of 16S ribosomal RNA gene sequencing and phylogenetic analysis. The results showed a high level of actinobacterial diversity with 16 different genera. These genera obtained as a result of phylogenetic analyzes are Streptomyces, Nonomuraea, Nocardia, Actinomadura, Micromonospora, Kribbella, Mycolicibacterium, Microbispora, Saccharopolyspora, Jiangella, Rhodococcus, Actinopolymorpha, Geodermatophilus, Dactylosporangium, Pseudonocardia and Nocardioides. Many isolates are identified as new species by our current research. Findings from this study showed that the soil of Marmara and Avşa Islands can be a good source of isolation for Actinobacteria.