AUTHOR=Shiu Jia-Ho , Yu Sheng-Ping , Fong Chia-Ling , Ding Jiun-Yan , Tan Chih-Jui , Fan Tung-Yung , Lu Chih-Ying , Tang Sen-Lin 

TITLE=Shifting in the Dominant Bacterial Group Endozoicomonas Is Independent of the Dissociation With Coral Symbiont Algae

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.01791

DOI=10.3389/fmicb.2020.01791

ISSN=1664-302X

ABSTRACT=<p>The coral-associated <italic>Endozoicomonas</italic> are dominant bacteria in the coral holobiont. Their relative abundance usually decreases with heat-induced coral bleaching and is proposed to be positively correlated with Symbiodiniaceae abundance. It remains unclear whether this phenomenon of decreased <italic>Endozoicomonas</italic> abundance is caused by temperature stress or a decreased abundance of Symbiodiniaceae. This study induced bleaching in the coral <italic>Euphyllia glabrescens</italic> using a dark treatment over 15 weeks. We examined shifts in <italic>Endozoicomonas</italic> abundance and experimentally reduced Symbiodiniaceae density. 16S rRNA gene amplicon sequencing was used to characterize the changes in bacterial community (incl. <italic>Endozoicomonas</italic>) over time, and the 16S rRNA gene copy number of <italic>Endozoicomonas</italic> was quantified by qPCR. We detected a high abundance of <italic>Endozoicomonas</italic> in <italic>E. glabrescens</italic> that underwent dark-induced bleaching. The results reveal that changes in the relative abundance of <italic>Endozoicomonas</italic> are unrelated to Symbiodiniaceae abundance, indicating that <italic>Endozoicomonas</italic> can be independent of Symbiodiniaceae in the coral holobiont.</p>