Identification and characterization of heat shock protein 90 (HSP90) in the hard coral Acropora tenuis in response to Irgarol 1051

Highlights: • The full-length cDNA of HSP90 was isolated from the hard coral, Acropora tenuis. • The body colours of corals were not affected by exposure to 1 μg/L of Irgarol 1051. • The coral HSP90 was down-regulated by exposure to 1 μg/L Irgarol 1051. • The coral HSP90 may be a useful biomarker to predict the effects of herbicides. - Abstract: To elucidate the effects of the herbicide Irgarol 1051 on the gene expression of heat shock protein 90 (HSP90) in hard corals, we isolated a full-length cDNA encoding HSP90 from Acropora tenuis, which has a deduced open reading frame of 732-amino acid residues with a predicted molecular mass of 84.5 kDa. The amino acid sequence of A. tenuis HSP90 showed a high degree of similarity with the hermatypic-coral HSP90 families. After a 7-d exposure to 1 or 10 μg/L of Irgarol, the body colours of corals in the 10 μg/L treatment group were significantly whiter (bleached), whereas no such effects were observed in the corals in the 1 μg/L treatment group. However, the expression level of coral HSP90 was significantly downregulated after exposure to both 1 and 10 μg/L Irgarol. These results suggest that A. tenuis HSP90 may be a useful molecular biomarker to predict bleaching caused by herbicides.