Genomic blueprint of Hahella chejuensis, a marine microbe producing an algicidal agent

Abstract

Harmful algal blooms, commonly called red tides, are phenomena caused by rapid proliferation and accumulation of certain microalgae in the ocean1. They increasingly haunt the coastal waters throughout the world in recent years, posing gruesome impacts on marine environments, aquatic industries, and public health2-5. Here we present the 7.2-megabase genome sequence of the marine heterotroph Hahella chejuensis and its pigment showing the lytic activity against red-tide phytoplanktons. Sequence analysis indicates that it has a large number of genes involved in regulation or transport, as well as a multitude of genes of functional equivalence or of possible foreign origin. Functions encoded in genomic islands include biosynthesis of exopolysacchrides, secondary metabolites and toxins, motility, adhesion, type III protein secretion, and pigmentation. Structural analysis of the pigment indicated that it is the well-known antibiotic prodigiosin. The pigment showed algicidal activity even at parts-per-billion concentrations. Collectively, our results suggest that H. chejuensis is well adapted to the marine environments employing diverse survival strategies, and the bacterium or its algicidal pigment might be feasible for use in mitigating algal blooms