Porites white patch syndrome (PWPS) is a coral disease recently described in the western Indian Ocean. This study aimed to isolate and identify potential pathogens associated with PWPS utilising both culture and non-culture screening techniques and inoculation trials. A total of 14 bacterial strains (those dominant in disease lesions, absent or rare in healthy tissues and considered potential pathogens in a previous study) were cultured and used to experimentally inoculate otherwise healthy individuals in an attempt to fulfil Henle-Koch's postulates. However, only one (P180R), identified as closely related (99-100% sequence identity based on 1.4 kb 16S RNA sequence) to Vibrio tubiashii, elicited signs of disease in tank experiments. Following experimental infection (which resulted in a 90% infection rate), the pathogen was also successfully re-isolated from the diseased tissues and re-inoculated in healthy corals colonies, therefore fulfilling the final stages of Henle-Koch's postulates. Finally we report that PWPS appears to be a temperature-dependent disease, with significantly higher tissue loss (ANOVA: df= 2, F=39.77, P<0.01) occurring at 30°C (1.45 ± 0.85 cm2 day−1 (mean ± SE)) compared to ambient temperatures of 28°C and 26°C (0.73 ± 0.80 cm2 day−1 (mean ± SE) and 0.51 ± 0.50 cm2 day−1 (mean ± SE), respectively).
PWPS bacterial cultures
Sequences (16S rRNA gene) of the bacterial isolates used in phase 1 of the inoculation experiment. The software used to create the data file (fasta) is Genesious.
Bacterial candidates (Infection trials)
Sequences (16S rRNA gene) of the bacterial strains (potential PWPS pathogens) used for infectivity experiements. The software used to create the data file (Fasta) is GENEIOUS Pro (V.5.6.6).
Nucleotide alignment (16S rRNA gene)
Nucleotide alignment of the isolate "P180R" (16S rRNA gene) performed with reference sequences related to multiple bacterial strains selected from NCBI using GENEIOUS alignment method.
MLST alignment
Mutlilocus sequence typing (MLST) alignment of the stain P180R using the partial sequences of 16S rRNA (1422 bp), pyrH (590 bp), recA (766 bp) and rpoA (802bp) genes. The sequences obtained for each gene were aligned with reference sequences related to multiple bacterial strains selected from NCBI using GENEIOUS alignment method
Nucleotide alignment (pyrH gene)
Nucleotide alignment of the isolate "P180R" (pyrH gene) performed with reference sequences related to multiple bacterial strains selected from NCBI using GENEIOUS alignment method.
PWPS bacterial cultures (corresponding codes and blast results)
Bacterial strains isolated from PWPS-infected Porites colonies.This is a "xlsx" file containing each bacterial strain codes with their respective blast results.
Tree for the 16S rRNA gene
Neighbour-joining phylogenetic tree for the 16S rRNA gene gene showing the relatedness of the strain P180R with reference Vibrio strains. The software used to create the data (Newick) is Geneious 6.1.5.
Tree for the pyrH gene
Phylogenetic trees built by the neighbour-joining method using the NKY model of GENEIOUSTM Pro (V.6.1.5) with bootstrap values based on 1000 replicates for the isolate "P180R" (pyrH gene).
Consensus tree (concatanation)
Consensus tree built by the neighbour-joining method using the NKY model of GENEIOUS Pro (V.6.1.5) with bootstrap values based on 1000 replicates for the isolate "P180R" (Partial sequences of 16S rRNA (1422 bp), pyrH (590 bp), recA (766 bp) and rpoA (802bp)).