The microbiome of the Red Sea coral Stylophora pistillata is dominated by tissue-associated Endozoicomonas bacteria

Abstract

Endozoicomonas bacteria were found highly associated with the coral Stylophora pistillata, and these bacteria are also ubiquitously associated with diverse corals worldwide. Novel Endozoicomonas-specific probes revealed that Endozoicomonas bacteria were abundant in the endodermal tissues of S. pistillata and appear to have an intimate relationship with the coral.

Fig 1

Phylogenetic distribution of coral-associated bacteria. Sequences were classified to the genus level with a minimum bootstrap value of 60%. Read counts from genera other than the 10 most common ones are summarized in the “others” category. The number of clones analyzed is shown in parentheses, and the number of reads analyzed by 454 sequencing is shown in Table 1. (A) S. pistillata (Sp1 to Sp5; n = 5)-associated bacteria detected by cloning and sequencing (CL) and 454 sequencing (454). (B) A. humilis (A to C; n = 3)- and P. damicornis (A to C; n = 3)-associated bacteria detected by cloning and sequencing.

Fig 2

FISH analysis. The mixed Endozoicomonas probes (Cy3, selected aggregates designated “ez”) within the tissues of S. pistillata (A, C) display a hybridization pattern similar to that of the general EUB338 bacterial probe (Cy5, selected aggregates designated “ba”) (B, D). Some cells in aggregates from similar specimens were also illuminated by the nonspecific probe NONEUB (Cy3, selected nonspecificity labeled “ns”) (E), and nematocyst cells (labeled “n”) were also illuminated by the NONEUB probe (F). Symbiodinium cells (S) are autofluorescent at the imaging wavelengths used (except in panel D, where cells faded under imaging). Each image is a compilation of two to four optical slices. The scale bars are approximately 8 μm.