title: Characterisation of an atypical manifestation of black band disease on Porites lutea in the Western Indian Ocean.
abstract: Recent surveys conducted on Reunion Island coral reefs revealed an atypical manifestation of black band disease on the main framework building coral, Porites lutea. This BBD manifestation (PorBBD) presented a thick lighter-colored band, which preceded the typical BBD lesion. Whilst BBD aetiology has been intensively described worldwide, it remains unclear if corals with apparently similar lesions across coral reefs are affected by the same pathogens. Therefore, a multidisciplinary approach involving field surveys, gross lesion monitoring, histopathology and 454-pyrosequencing was employed to provide the first comprehensive characterization of this particular manifestation. Surveys conducted within two geomorphological zones over two consecutive summers and winters showed spatial and seasonal patterns consistent with those found for typical BBD. Genetic analyses suggested an uncharacteristically high level of Vibrio spp. bacterial infection within PorBBD. However, microscopic analysis revealed high densities of cyanobacteria, penetrating the compromised tissue as well as the presence of basophilic bodies resembling bacterial aggregates in the living tissue, adjacent to the bacterial mat. Additionally, classical BBD-associated cyanobacterial strains, genetically related to Pseudoscillatoria coralii and Roseofilum reptotaenium were identified and isolated and the presence of sulfate-reducers or sulfide-oxidizers such as Desulfovibrio and Arcobacter, previously shown to be associated with anoxic microenvironment within typical BBD was also observed, confirming that PorBBD is a manifestation of classical BBD.
authors.affiliation: Agence pour la Recherche et la VAlorisation Marines (ARVAM), Saint-Denis, Réunion, France; Oceanographic Research Institute (ORI), Durban, KwaZulu-Natal, South Africa; UMR ENTROPIE, Labex CORAIL, Research Institute for the Development (IRD), Saint-Denis, Réunion, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Séré
authors.affiliation: Unité Mixte de Recherche "Processus Infectieux en Milieu Insulaire Tropical" (UMR PIMIT), Université de La Réunion, Inserm1187, CNRS9192, IRD249, Plateforme de Recherche CYROI , Saint Denis , Réunion , France.
authors.forename: David A
authors.initials: DA
authors.lastname: Wilkinson
authors.affiliation: Oceanographic Research Institute (ORI) , Durban , KwaZulu-Natal , South Africa.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Schleyer
authors.affiliation: UMR ENTROPIE, Labex CORAIL, Research Institute for the Development (IRD) , Saint-Denis , Réunion , France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Chabanet
authors.affiliation: Agence pour la Recherche et la VAlorisation Marines (ARVAM) , Saint-Denis , Réunion , France.
authors.forename: Jean-Pascal
authors.initials: JP
authors.lastname: Quod
authors.affiliation: Unité Mixte de Recherche "Processus Infectieux en Milieu Insulaire Tropical" (UMR PIMIT), Université de La Réunion, Inserm1187, CNRS9192, IRD249, Plateforme de Recherche CYROI , Saint Denis , Réunion , France.
authors.forename: Pablo
authors.initials: P
authors.lastname: Tortosa
keywords: Bacterial communities; Coral disease; Metabarcoding; Porites black band disease; Reunion Island; Scleractinian corals