Molecular Identification of Symbiotic Zooxanthellae on Coral Reefs off Kish Island, Persian Gulf

Coral reefs of the Persian Gulf are normally subject to extreme environmental conditions including high salinity and seasonal variation in temperature. Previous studies elsewhere have shown that some Symbiodinium taxa such as the clade D group may be more resistant to heat stress than others. This study is the first to use molecular techniques to identify the Symbiodinium of the Iranian coral reefs on the basis of clade identification.

Samples of eight coral species were collected at two different depths from the eastern part of Kish Island in the northern Persian Gulf. Partial 28S nuclear ribosomal (nr) DNA of Symbiodinium (D1/D2 domains) were amplified by Polymerase Chain Reaction (PCR). PCR products were analyzed using Single Strand Confirmation Polymorphism (SSCP) and the phylogenetic analyses of the LSU DNA sequences.

The results showed that there are at least two clades of Symbiodinium from Kish Island. Clade D was detected from 8 of the coral species while clade C was found in 2 of species only.

The dominance of clade D might be explained by high temperatures typical for the Persian Gulf.