Year: 2025
Type: article
Abstract: Marine actinobacteria are valuable biological sources of various bioactive compounds, such as antibiotics, anticancer agents, and immunosuppressants [1].However, since the 2000s, identification of new species and antibiotics has been declining, coinciding with the increasing prevalence of multidrug resistance; therefore, these microorganisms are important for the identification of novel therapeutic agents [2].They also exhibit high biosynthetic potential; however, many biosynthetic gene clusters (BGCs) associated with secondary metabolite production are not expressed under standard laboratory conditions, limiting access to their chemical diversity [3].Therefore, genome sequencing and cryptic BGC identification are crucial for the discovery of new bioactive metabolites in these microorganisms [4].In this study, we aimed to isolate marine actinobacteria from marine sponges and conduct whole-genome sequencing to identify novel secondary metabolites.Additionally, we aimed to characterize their BGCs.We identified a novel marine actinobacteria, Streptomyces sp.MMBL 11-3, isolated from the deep-sea sponge, Spheciospongia panis.This sponge was collected from the Moon Island in Jeju, South Korea, with the assistance of the Korea Institute of Ocean Science & Technology.The harvested marine sponge was processed into a liquid sample via grinding and filtration.The liquid sample was overlaid on the ISP4 (BD DIFCO, USA), ISP2 (BD DIFCO, USA), and marine agar (BD DIFCO) media supplemented with 2% NaCl, 10 μM nalidixic acid, and 20 μM cycloheximide to selectively isolate actinobacteria, as previously described [5].Subsequently, Streptomyces sp.MMBL 11-3 was isolated from the colonies exhibiting characteristic actinobacterial morphology.The isolated strain was cultured in 500 ml of tryptic soy broth (BD DIFCO) at 28℃ for two days to extract the genomic DNA (gDNA) using the Wizard DNA Purification Kit (Promega, USA).The extracted gDNA was subjected to next-generation sequencing using the Illumina platform (for short reads) and PacBio Sequel System (for long reads; sequencing was performed by Macrogen, Marine actinobacteria are rich sources of bioactive compounds; however, many biosynthetic gene clusters (BGCs) are not expressed under standard conditions.In this study, we identified a novel actinobacterium, Streptomyces sp.MMBL 11-3, isolated from the deep-sea sponge, Spheciospongia panis, near Moon Island, Jeju, Republic of Korea.Whole-genome sequencing revealed a 9.5-Mb genome with 34 BGCs, including terpene, non-ribosomal peptide synthetase, polyketide synthase, and ribosomally synthesized and post-translationally modified peptide BGCs.Phylogenetic analysis confirmed its close relationship with other Streptomyces species.Therefore, Streptomyces sp.MMBL 11-3 can be used to identify novel secondary metabolites using genomic approaches in future studies.
Institution: Inha University
Language: English
Subfield: Pharmacology
Field: Medicine
Domain: Health Sciences
SDG: Life below water
Open Access status: bronze
Awards: G1734341162, G897630140
OpenAlex ID: W4411770041