Vibrio coralliilyticus Strain OCN008 Is an Etiological Agent of Acute Montipora White Syndrome
ABSTRACTIdentification of a pathogen is a critical first step in the epidemiology and subsequent management of a disease. A limited number of pathogens have been identified for diseases contributing to the global decline of coral populations. Here we describeVibrio coralliilyticusstrain OCN008, which induces acuteMontiporawhite syndrome (aMWS), a tissue loss disease responsible for substantial mortality of the coralMontipora capitatain Kāne‘ohe Bay, Hawai‘i. OCN008 was grown in pure culture, recreated signs of disease in experimentally infected corals, and could be recovered after infection. In addition, strains similar to OCN008 were isolated from diseased coral from the field but not from healthyM. capitata. OCN008 repeatedly induced the loss of healthyM. capitatatissue from fragments under laboratory conditions with a minimum infectious dose of between 107and 108CFU/ml of water. In contrast,Porites compressawas not infected by OCN008, indicating the host specificity of the pathogen. A decrease in water temperature from 27 to 23°C affected the time to disease onset, but the risk of infection was not significantly reduced. Temperature-dependent bleaching, which has been observed with theV. coralliilyticustype strain BAA-450, was not observed during infection with OCN008. A comparison of the OCN008 genome to the genomes of pathogenicV. coralliilyticusstrains BAA-450 and P1 revealed similar virulence-associated genes and quorum-sensing systems. Despite this genetic similarity, infections ofM. capitataby OCN008 do not follow the paradigm forV. coralliilyticusinfections established by the type strain.