Symbiodinium tridacnidorum sp nov., a dinoflagellate common to Indo-Pacific giant clams, and a revised morphological description of Symbiodinium microadriaticum Freudenthal, emended Trench & Blank
Symbiodinium tridacnidorum sp nov., a dinoflagellate common to Indo-Pacific giant clams, and a revised morphological description of Symbiodinium microadriaticum Freudenthal, emended Trench & Blank
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DOI：
10.1080/09670262.2015.1018336
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发表时间：
2015-05-01
影响因子：
2.4
通讯作者：
Lajeunesse, Todd C.
中科院分区：
文献类型：
--
作者：
Lee, Sung Yeon;Jeong, Hae Jin;Lajeunesse, Todd C.
共生鞭毛属包含许多遗传上不同的谱系，这些谱系在形态上是隐伏的。然而，最近对两个远亲共生菌属的A‘和E’支系的运动期（乳石）中可见的板块配方的详细形态学评估显示是不同的。虽然在A枝中有几个正式描述的物种，但遗传证据表明，还有更多的物种尚未被描述。我们将重点放在这一群体中密切相关的系统发育谱系上，以研究形态学上的差异是否可以与遗传和生态证据一起用于描述新物种。我们从培养的和野外采集的共生菌微adriatium （sensu Trench & Blank, 1987）和共生菌sp.(主要与巨蛤和太平洋Cassiopea水母（包括ITS2 A3谱系的成员，sensu LaJeunesse 2001）样品中发现了核（内部转录间隔段（ITS）和大亚基rDNA）、叶绿体（cp23S）和线粒体（cob）基因序列的固定差异。对trench&blank（1987）在其修订描述中使用的S. microadriatium菌株（CCMP2464）和从印太巨蛤（Tridacninae亚科）培养的两株A3型菌株（CCMP832和rt-272）制定了圆形平板表格。A3型的科波底板型由小板(x)、长形角小泡（EAV）、5、6a、8、9-11s、2排带、7和3（偶尔也有2）组成，与微adriaticum不同，其板型为x、EAV、4、5a、8、9-13s、2排带、6和2。通过形态学和遗传比较，我们鉴定出了一种新的印太物种：Symbiodinium tridacnidorum sp. nov.。S. microadriaticum的板块排列似乎更类似于S. natans的远亲（也属于A枝）。当将所有三个进化枝A种的表格与S. voratum（进化枝E）进行比较时，物种之间形态分化的数量与它们的遗传分化程度不相对应。
The dinoflagellate genus Symbiodinium contains numerous genetically distinct lineages that appear morphologically cryptic'. However, detailed morphological assessments of plate formulae visible in the motile phase (mastigote) of two distantly related Symbiodinium spp., representing Clades A' and E', were recently shown to be different. While there are several formally described species in Clade A, genetic evidence indicates that many more remain uncharacterized. We focused on closely related phylogenetic lineages within this group to examine whether differences in morphology can be used together with genetic and ecological evidence to describe new species. We found fixed differences in nuclear (internal transcribed spacer (ITS) and large subunit rDNA), chloroplast (cp23S) and mitochondrial (cob) gene sequences from cultured and field-collected samples of Symbiodinium microadriaticum (sensu Trench & Blank, 1987) and Symbiodinium sp. associated predominantly with giant clams and Pacific Cassiopea jellyfish (comprising members of the ITS2 A3 lineage, sensu LaJeunesse 2001). Amphiesmal plate tabulations were formulated for the strain of S. microadriaticum (CCMP2464) used by Trench & Blank (1987) in their emended description, and two strains of type A3 (CCMP832 and rt-272) cultured from Indo-Pacific giant clams in the subfamily Tridacninae. The Kofoidian plate formula for type A3 consists of the small plate (x), the elongated amphiesmal vesicle (EAV), 5, 6a, 8, 9-11s, a 2-row cingulum, 7 and 3 (and occasionally 2), and is different from S. microadriaticum, which has a plate formula of x, EAV, 4, 5a, 8, 9-13s, a 2-row cingulum, 6 and 2. Based on morphological and genetic comparisons, we recognized Symbiodinium tridacnidorum sp. nov., a new Indo-Pacific species. The plate arrangement exhibited by S. microadriaticum appears to be more similar to the distantly related S. natans (also in Clade A). When the tabulations for all three Clade A species are compared with S. voratum (Clade E), the amount of morphological differentiation between species does not correspond to their degree of genetic divergence.