北部湾涠洲岛珊瑚礁海域共生藻(Symbiodinium sp.)种类鉴定

Identification of Symbiodinium sp.from Weizhou Island,a coral reef area in Beibu Gulf

2021年12月在北部湾涠洲岛珊瑚礁海域分离纯化得到两株共生藻(BGERL71、BGERL72),通过光学显微镜和荧光显微镜对其进行形态学初步鉴定,发现其与共生藻细胞大小和形态特征相似,进而基于LSU rDNA和ITS序列构建最大似然法(ML)和邻接法(NJ)系统发育树并计算遗传距离,结果显示共生藻Clade A-F形成了6个独立的分支,其中涠洲岛两株共生藻与Clade A下的自在共生藻(Symbiodinium natans)聚在一起,它们与自在共生藻藻株的遗传距离亦为最小,分别为0.000~0.002和0.000,从而确定这两株共生藻属于自在共生藻。本研究结果丰富了我国北部湾及南海北部珊瑚礁海域的共生藻种类多样性,为该海域珊瑚礁保护提供生物学基础数据。

In December 2021,two strains of Symbiodinium sp.(BGERL71 and BGERL72)were isolated and purified from Weizhou Island,a coral reef area in Beibu Gulf.Morphological identification was performed using light and fluorescence microscopes,and their cell sizes and morphological characteristics were found to be similar to those of Symbiodinium sp.Using LSU rDNA and ITS sequences,Maximum Likelihood(ML)and Neighbor-Joining(NJ)phylogenetic trees were constructed,and genetic distances were calculated.The results showed that Clade A-F in the genus Symbiodinium formed six independent branches,among which BGERL71 and BGERL72 from Weizhou Island clustered with Symbiodinium natans under Clade A,and had the smallest genetic distance with S.natans,0.000~0.002 and 0.000,respectively.Thus,the strains of BGERL71 and BGERL72 belonged to S.natans.This study demonstrates the diversity of Symbiodinium species in the coral reef areas of Beibu Gulf and the northern South China Sea,providing primary biological data for coral reef conservation in the area.