UC San Diego

Filamentous tropical cyanobacteria such as Moorea producens live surrounded by a community of heterotrophic bacteria. However, these heterotrophic bacteria and their interactions with the cyanobacteria have not been extensively studied. During efforts to sequence the genome of a culture of M. producens strain JHB, the 5.99 Mb genome of an unknown associated bacterium was discovered. This bacterium was found to belong to phylum Acidobacteria, subgroup 22, and is further referred to in this thesis as Mor1. Mor1 was found to predominantly exist on the outside surfaces of M. producens JHB sheaths. Currently, Mor1 is unable to be cultured separately from M. producens JHB, and was found to be present only in laboratory cultures of M. producens strains. A co-culturing experiment between M. producens JHB with Mor1 and other cyanobacterial strains indicated that Mor1 failed to transfer to other cyanobacteria. These data support a specific relationship between Mor1 and M. producens, although further experiments would be necessary to confirm a symbiotic relationship between the two organisms. Overall, the study of this previously unknown Acidobacteria strain associated with M. producens JHB can provide information about an understudied phylum of heterotrophic bacteria as well as a potential novel symbiosis