Antagonistic Interactions of Sponge-Associated Actinobacteria against Heterotrophic Bacteria from Sponge and Ambient Water

In the present study, 11 sponge-associated Actinobacteria showed 316 inhibitory interactions against 75 heterotrophic bacteria as each Actinobacteria inhibited the growth of >1 bacterial isolates from the sponge and ambient water. The antagonistic activity depended on the source of isolation and the taxonomic group of heterotrophic bacteria. The order of inhibition of bacteria by Actinobacteria was ambient water > cortex > mesohyl tissues of sponge. The absence of certain genera in the sponge might be because of the inhibition by sponge-associated Actinobacteria. Hence, the antagonistic property of Actinobacteria in the sponges may influence the selection of resident sponge-associated bacteria.