Characterization of Aspergillus sydowii (Thom et Church), a fungal pathogen of Caribbean sea fan corals

Abstract

In the Caribbean, the fungus Aspergillus sydowii is currently causing an epizootic among sea fan corals (Gorgonia spp.). To elucidate potential factors that may have facilitated the emergence of this disease, we characterized and compared temperature requirements, susceptibility to coral crude extracts, and metabolic profiles of pathogenic (marine) and non-pathogenic (terrestrial) strains of A. sydowii. Growth of all A. sydowii strains were observed at all temperatures tested (22–36 °C) with an optimum of approximately 30 °C. Sea fan crude extracts inhibited growth of A. sydowii but were less effective at higher temperatures. Thus, temperature is likely to have a strong influence on the dynamics of the Gorgonia–Aspergillus interaction by promoting the growth of the pathogen while reducing the efficacy of host resistance. Metabolically, marine A. sydowii strains pathogenic to sea fans were distinct from non-pathogenic terrestrial strains.