Re-introduction of a bioactive bacterial endophyte back to its seaweed (Ulva sp.) host, influences the host’s microbiome

Ulva is a commercially important marine macroalga. It hosts both epiphytes and endophytes. The latter are assumed to protect through secondary metabolites. Previously, we demonstrated bioactive endophytes from macroalgae with great potential control diseases of aquaculture. In this study, introduced bacterial endophyte back into its original host ( sp.) survival over time in fresh freeze-dried sp. We visualized the endophyte’s location seaweed using Green Fluorescent Protein (GFP) reporter gene. isolate colonized intercellular space survived for at least 5 months fresh, 12 algae, while maintaining bioactivity against aquaculture pathogen Streptococcus iniae . studied influence on community found that once introduced, significantly changed algal microbiota diversity abundance. Two ’s associated species were quantified time, suggesting different trends absolute abundance these bacteria between treatments. To best our knowledge, first report successful introduction an endophytic microorganism macroalgal tissue. These findings may be useful applied research management diseases.