Selective growth promotion of bloom-forming raphidophyte Heterosigma akashiwo by a marine bacterial strain

Aiko Higashi, Yoshiko Fujitani, Natsuko Nakayama, Akio Tani, Shoko Ueki

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Algal bloom is typically caused by aberrant propagation of a single species, resulting in its predomination in the local population. While environmental factors including temperature and eutrophication are linked to bloom, the precise mechanism of its formation process is still obscure. Here, we isolated a bacterial strain that promotes growth of Heterosigma akashiwo, a Raphidophyceae that causes harmful algal blooms. Based on 16S rRNA gene sequence, the strain was identified as Altererythrobacter ishigakiensis, a member of the class Alphaproteobacteria. When added to culture, this strain facilitated growth of H. akashiwo and increased its cell culture yield significantly. Importantly, this strain did not affect the growth of other raphidophytes, Chattonella ovate and C. antiqua, indicating that it promotes growth of H. akashiwo in a species-specific manner. We also found that, in co-culture, H. akashiwo suppressed the growth of C. ovate. When A. ishigakiensis was added to the mixed culture, H. akashiwo growth was facilitated while C. ovate propagation was markedly suppressed, indicating that the presence of the bacterium enhances the dominance of H. akashiwo over C. ovate. This is the first example of selective growth promotion of H. akashiwo by a marine bacterium, and may exemplify importance of symbiotic bacterium on algal bloom forming process in general.

Original languageEnglish
Pages (from-to)150-156
Number of pages7
JournalHarmful Algae
Publication statusPublished - Dec 1 2016


  • Heterosigma akashiwo
  • Marine bacterium
  • Mutualism
  • Selective growth promotion

ASJC Scopus subject areas

  • Aquatic Science
  • Plant Science


Dive into the research topics of 'Selective growth promotion of bloom-forming raphidophyte Heterosigma akashiwo by a marine bacterial strain'. Together they form a unique fingerprint.

Cite this