Bacterial consortium associated with the“black disease＂of reef-building corals
Date Issued
2008
Date
2008
Author(s)
Liao, Ming-Hui
Abstract
Coral diseases are one of the major natural disturbances that threat the survivalf coral reefs worldwide. However, the characterization and mechanism of infectionave been difficult in understanding the outbreak of coral diseases due to theimitation of applying classical microbiological assays. In this thesis, the bacteriaonsortium of the “black disease” caused by a black mat-like sponge, Terpiososhinota, was characterized by electronic microscopy, denaturing gradient gellectrophoresis (DGGE), and 16S ribosomal DNA library construction. In order tonderstand the possible pathogenic bacteria in “black disease”, the specificity of T.oshinota associated bacterial community and the variation between sponge-infectedSI) and non-sponge-infected (NSI) Porites lutea associated bacterial communityere investigated in the fringing reef of the Green Island (Lutao), where outbreak oferpios sponge was first reported in 2006.esult shows that the bacterial communities from seawater, sponge, and coralere specific. T. hoshinota associated bacterial community was specific and theominant bacteria group was autotrophic Cyanobacteria. The Cyanobacteriassociated with T. hoshinota were supposedly a new Cyanobacteria species asemonstrated by 16S rDNA sequence with a unique morphology. Furthermore, theigh abundance of cyanobacteria in T. hoshinota may contribute positively to T.iioshinota outbreak. On the other hand, the diversity and composition similarity ofacterial community associated with SI and NSI P. lutea were analyzed usingOTUR and LIBSHUFF. In NSI P. lutea, the dominant bacterial groups wereammaproteobacteria, Cyanobacteria, and unclassified bacteria; however, in SI P.utea, Gammaproteobacteria and Alphaproteobacteria were major groups and thebundance of Cyanobacteria and unclassified bacteria were low. In previous studies,here were diverse coral holobiont on a coral. The natural coral holobiont changed toominant bacteria group with abundance of opportunistic bacteria when coralsxperience environmental stress; similar situation was observed in SI P. lutea. Thencrease of the abundance of Gammaproteobacteria is probably related tonvironmental stress (sponge or seawater pollution). In addition, the unexpectedmergence of alphaproteobacteria could be opportunistic bacteria because ofisturbance of natural bacterial community. Disturbance of coral holobiont possibleoss the normal symbiont function for coral and it directly or indirectly supposed toesult in coral disease. Coral associated microbes were variable in differentnvironment and may be a good bioindicator for environmental stress; therefore,uilding up a bioindicator, a long term investigation is apparently essential.
Subjects
sponge
Cyanobacteria
coral disease
coral microbiology
uncultured molecular method
SDGs
Type
thesis
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