The presence of genes encoding enzymes that digest carbohydrates in coral genomes and analysis of their activities

Numerous enzymes that digest carbohydrates, such as cellulases and chitinases, are present in various organisms (e.g., termites, nematodes, and so on). Recently, the presence of cellulases and chitinases has been reported in marine organisms such as urchin and bivalves, and their several roles in marine ecosystems have been proposed. In this study, we reported the presence of genes predicted to encode proteins similar to cellulases and chitinases in the genome of the coral Acropora digitifera, their gene expression patterns at various life stages, and cellulose- and chitin-degrading enzyme activities in several coral species (A. digitifera, Galaxea fascicularis, Goniastrea aspera, Montipora digitata, Pavona divaricata, Pocillopora damicornis, and Porites australiensis). Our gene expression analysis demonstrated the expressions of these cellulase- and chitinase-like genes during various life stages, including unfertilized eggs, fertilized eggs, zygotes, planula larvae, primary polyps and adults of A. digitifera. Agar plate assays confirmed cellulase and chitinase activities in the tissues extracted from adult branches of several coral species. These results suggested that corals are able to utilize cellulases and chitinases in their life histories.