PRESENTATION OF THE FIRST PHAGE THAT INFECTS THE LD28 CLADE, AN ABUNDANT FRESHWATER METHYLOTROPHIC BACTERIAL GROUP

초록

Objectives: Bacteriophages (phages) are the most abundant biological entities on earth and known to be present as 10-times more abundant than their host bacteria. In aquatic environments, their abundances are calculated as ~106 particles/ml of seawater and ~107 particles/ml of lake water. Most importantly, bacteriophages participate in the nutrient cycling in aquatic environments. Not only that they interfere with bacteria-mediated various nutrient cycles by predation, but they also contribute in increase of the dissolved carbon source through lysis of bacterial cells. Despite of their extensive population, bacteriophages infecting major groups of freshwater heterotrophic bacteria have been rarely isolated, leaving large unexplainable area in freshwater viral metagenome studies. To our knowledge, no phage has been identified and isolated that infects major freshwater heterotrophic bacterial groups, such as acI, acIV, LD12, Limnohabitans, Polynucleobacter, and LD28. In this study, we attempted to isolate bacteriophages infecting the LD28 clade, one of the major freshwater bacterial groups and perform in-depth genome study of the isolated bacteriophage for better understanding of freshwater microbial ecology.