Onset and establishment of diazotrophs and other bacterial associates in the early life history stages of the coral Acropora millepora. Issue 19 (October 2014)

• Record Type: Journal Article
• Authors: Lema, Kimberley A.; Bourne, David G; Willis, Bette L.
• Is Part Of: Molecular ecology. Volume 23:Issue 19(2014)
• Page Start: 4682
• Page End: 4695
• Publication Date: 2014-10
• Subjects: Molecular ecology -- Periodicals; Molecular population biology -- Periodicals; 576
• DOI: 10.1111/mec.12899
• Languages: English
• ISSNs: 0962-1083

Abstract

<abstract abstract-type="main" id="mec12899-abs-0001"> <title>Abstract</title> <p>Early establishment of coral–microbial symbioses is fundamental to the fitness of corals, but comparatively little is known about the onset and succession of bacterial communities in their early life history stages. In this study, bacterial associates of the coral <italic>Acropora millepora</italic> were characterized throughout the first year of life, from larvae and 1‐week‐old juveniles reared in laboratory conditions in the absence of the dinoflagellate endosymbiont <italic>Symbiodinium</italic> to field‐outplanted juveniles with established <italic>Symbiodinium</italic> symbioses, and sampled at 2 weeks and at 3, 6 and 12 months. Using an amplicon pyrosequencing approach, the diversity of both nitrogen‐fixing bacteria and of bacterial communities overall was assessed through analysis of <italic>nifH</italic> and 16S rRNA genes, respectively. The consistent presence of sequences affiliated with diazotrophs of the order <italic>Rhizobiales</italic> (23–58% of retrieved <italic>nifH</italic> sequences; 2–12% of 16S rRNA sequences), across all samples from larvae to 12‐month‐old coral juveniles, highlights the likely functional importance of this nitrogen‐fixing order to the coral holobiont. Dominance of <italic>Roseobacter</italic>‐affiliated sequences (>55% of retrieved 16S rRNA sequences) in larvae and 1‐week‐old juveniles, and the consistent presence of sequences related to <italic>Oceanospirillales</italic> and <italic>Altermonadales</italic> throughout all early life history stages, signifies their potential importance as coral associates. Increased diversity of bacterial communities once juveniles were transferred to the field, particularly of <italic>Cyanobacteria</italic> and <italic>Deltaproteobacteria</italic>, demonstrates horizontal (environmental) uptake of coral‐associated bacterial communities. Although overall bacterial communities were dynamic<italic>, </italic> bacteria with likely important functional roles remain stable throughout early life stages of <italic>Acropora millepora</italic>.</p> </abstract>