Culture-dependent diversity of Actinobacteria associated with seagrass (Thalassia hemprichii)

A total of 110 culturable actinobacteria associated with seagrass (Thalassia hemprichii) were isolated using six different culture media, and their bioactivity potentials were analysed based on their genetic background on polyketide synthetase (PKS) and nonribosomal peptide synthetase (NRPS) gene sequences. Though the using of RFLP technique for sequencing and phylogenetic analysis, these selected 33 culturable isolates identified as belonging to ten genera of actinobacteria including Streptomyces, Micromonospora, Saccharomonospora, Mycobacterium, Actinomycetospora, Nonomuraea, Verrucosispora, Nocardiopsis, Microbacterium and Glycomyces. Four of the strains were unable to be assigned to currently known species and might be candidates of novel species. To our knowledge, this is the first report about culturable actinobacteria associated with seagrass and the isolate classified as Verrucosispora was first recorded to be isolated from plant. Most of the isolates harbor NRPS and PKS genes, which might indicate that these strains have great potential in production of bioactive natural compounds.