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Amplicon pyrosequencing reveals spatial and temporal consistency in diazotroph assemblages of the A cropora millepora microbiome
Author(s) -
Lema Kimberley A.,
Willis Bette L.,
Bourne David G.
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12366
Subject(s) - diazotroph , biology , holobiont , coral , pyrosequencing , rhizobia , ecology , symbiosis , nitrogen fixation , bacteria , gene , genetics
Summary Diazotrophic bacteria potentially play an important functional role in supplying fixed nitrogen to the coral holobiont, but the value of such a partnership depends on the stability of the association. Here we evaluate the composition of diazotroph assemblages associated with the coral A cropora millepora throughout four seasons and at two reefs, an inshore and an offshore (mid‐shelf) reef on the G reat B arrier R eef, A ustralia. Amplicon pyrosequencing of the nifH gene revealed that diazotrophs are ubiquitous members of the bacterial community associated with A . millepora . Rhizobia (65% of the overall nifH sequences retrieved) and particularly B radyrhizobia sp .‐ affiliated sequences (> 50% of rhizobia sequences) dominated diazotrophic assemblages across all coral samples from the two sites throughout the year. In contrast to this consistency in the spatial and temporal patterns of occurrence of diazotroph assemblages, the overall coral‐associated bacterial community, assessed through amplicon sequencing of the general bacterial 16S ribosomal RNA gene, differed between inshore and mid‐shelf reef locations. Sequences associated with the O ceanospirillales family, particularly with E ndozoicomonas sp., dominated bacterial communities associated with inshore corals. Although rhizobia represented a variable and generally small fraction of the overall bacterial community associated with A . millepora , consistency in the structure of these diazotrophic assemblages suggests that they have a functional role in the coral holobiont.