First Report of the Endophytic Bacteria Associated with Phormidium sp.

Abstract

Recent molecular studies on endophytic bacterial diversity have revealed a large richness of species. Associations between endobiotic bacterial-algae interactions have been studied for more than 40 years but were, up to now, never molecularly analyzed within the filamentous Cyanobacteria Phormidium. Therefore, the endophytic bacteria associated with fresh microalgae Phormidium, a group of ubiquitous photosynthetic organisms that play an important role in aquatic ecosystems, has been investigated. To study this partnership, Phormidium sp. was cultured in BG-11 medium using optimal conditions, and after the incubation period, cell biomass was obtained. Total genomic DNA from biomass was extracted and used for endophytic bacteria determination by using the 16S rRNA gene. Sequencing results revealed that a total of seven endophytic bacteria living within the cytoplasm of the host Phormidium sp. have been identified, including six bacteria belonging to three genera, namely Sphingomonas, Sphingopyxis, and Stenotrophobacter and while one bacteria remained unidentified due to low sequence homology in the GenBank database. The results highlighted the importance of endophytic bacteria associated with Phormidium sp. for the first time by using sequence-based identification.