深圳杨梅坑海域造礁石珊瑚共生藻分类和遗传多样性研究

Classification and genetic diversity analysis of Symbiodinium in scleractinia coral from Yangmeikeng sea area in Shenzhen

通过核糖体ITS(Internal Transcribed Spacer)的核苷酸序列研究了深圳杨梅坑海域20种47个造礁石珊瑚样本的共生藻。通过ITS序列分析,与GenBank上的4种不同的共生藻构建Neighbor-Joining聚类树,进行石珊瑚共生藻分类和遗传多样性分析。结果表明,该海域的造礁石珊瑚共生藻属于2种不同的种类(亚系群),19个样品属于C1亚系群共生藻,1个样品属于C15亚系群共生藻,C1和C15两个亚系群共生藻之间的遗传距离为0. 01。将深圳杨梅坑海域得到的ITS序列与NCBI数据库上的福建东山海域、广东徐闻地区的C1系共生藻进行比对,只有深圳杨梅坑海域藻类样本平均(A+T)碱基含量为49. 4%,(A+T)含量小于(G+C)含量。构建Neighbor-Joining聚类树表明,深圳杨梅坑海域石珊瑚共生藻与福建东山海域的亲缘关系较近,而与广东徐闻地区的亲缘关系较远,地理隔离是主要的因素。

This study analyzed the nucleotide sequences of Internal Transcribed Spacer (ITS) from Symbiodinium of 20 coral species. A total of 47 samples were collected from Yangmeikeng sea area in Shenzhen. Through ITS sequence analysis, a Neighbor-Joining tree was constructed with 4 different Symbiodinium groups in GenBank. The results show that Symbiodinium of scleractinia corals in this sea area belong to 2 different species (subgroups), 19 samples belong to the C1 subgroup, 1 sample belongs to the C15 subgroup. The Symbiodinium ’s genetic distance between C1 and C2 subpopulations is 0.01. Comparing with the Symbiodinium ’s ITS sequences of C1 subgroup obtained from Yangmeikeng sea area in Shenzhen, the Dongshan sea area of Fujian Province and the Xuwen sea area of Guangdong Province, we found that the average (A+T) base content of algal samples is 49.4%, which is less than (G+C) in Yangmeikeng sea area. The construction of Neighbor-Joining tree shows that Symbiodiniu from Dongshan and Yangmeikeng sea areas has a closer relationship compared with that from Xuwen. Thus, it is suggested that geographical isolation may be the main factor for the difference.