Molecular Taxonomy and Diversity of Symbiodinium Spp. Based on 28S rDNA Sequences Within 15 Coral Species in Daao Bay, Shenzhen

The identity and diversity Symbiodinium spp. of scleractinian corals are valuable to understand the response of reef ecosystems to environment change. The molecular taxonomy and genetic diversity of Symbiodinium of scleractinian coral were studied by specific amplification and sequencing of 28S rDNA, which belong to 5 families, 9 genera and 15 species in Daao Bay, Shenzhen. The 28S rDNA sequence of Symbiodinium from 45 samples of scleractinian corals was obtained by direct PCR sequencing. The molecular phylogenetic tree was constructed by using the method of Neighbor-Joining (NJ). The Symbiodinium of reef coral in Daao sea area of Shenzhen could be divided into two groups of Symbiodinium. Among them, 11 species belong to group D and 4 species belong to group C, and the average contents of G+C base and A+T base of 28 s rDNA gene of reef coral Symbiodinium in this area are similar. The results showed that the gene evolution rate of 28 s rDNA was fast, which was suitable for the identification of coral reef coral Symbiodinium community. The ability of light utilization and resistance of reef coral Symbiodinium in Daao sea area were strong, but the diversity is low. It suggests that the symbiotic system of reef coral Symbiodinium is fragile and poor resistance to external environmental pressure in this area. This single Symbiodinium with the scleractinian coral strategy may be an adaptation to the environment stress in this area. (paper)