一种绿色真江蓠的分子鉴定

Molecular identification of a green type of Gracilaria vermiculophylla

应用rDNA-ITS和线粒体cox1片段扩增序列,分析了厦门杏林湾的2株绿色未知江蓠（Gracilaria sp.;四分孢子体GR-1和雌配子体GR-2）及2株紫褐色真江蓠（G.vermiculophylla;四分孢子体PU-1和雌配子体PU-2）.运用MEGA5.0估算了4个供试样本与GenBank中相似度最高序列的遗传距离并构建了系统发育树.ITS序列分析显示绿色未知江蓠GR-1、GR-2都与真江蓠聚集在一起,推断两者与真江蓠的亲缘关系非常近.cox1片段序列分析表明,绿色未知江蓠GR-1、GR-2和紫褐色真江蓠PU-1、PU-2都与索引的真江蓠聚集在相同类群.其中GR-1、GR-2与真江蓠JQ619142、JQ619143的相似度都为100%,它们之间的遗传距离范围在0.000～0.002,低于种群内部的遗传距离范围0.000～0.015,从分子水平上确定了绿色未知江蓠是真江蓠.联合ITS和cox1片段序列的分子标记适用于真江蓠的种质鉴定.

In this paper,genetic analyses of ITS region and mitochondrial cox1 partial sequences were employed for identifying 2 green Gracilaria sp.（ Tetrasporophyte GR-1,Female gametophyte GR-2） and 2 puce Gracilaria vermiculophylla（ Tetrasporophyte PU-1,Female gametophyte PU-2） from Xinglin Bay of Xiamen. These sequences together with related highest similar sequences downloaded from the GenBank were applied to calculate genetic distances and construct phylogenetic trees using MEGA5. 0 software. The ITS region sequences analyses showed that both green Gracilaria sp. GR-1 and GR-2 were highly related to G. vermiculophylla. What＇s more,the phylogenesis of cox1 partial sequences revealed that GR-1,GR-2,PU-1 and PU-2 were synonymously clustered with G. vermiculophylla. Both GR-1 and GR-2 were completely identical to the reported G. vermiculophylla JQ619142 and JQ619143, and the genetic distances among them ranged from 0. 000 to 0. 002,which were lower than the value of distances within population ranged from 0. 000 to 0. 015. It was indicated that the type of green Gracilaria sp. was G. vermiculophylla. These results also suggested that the combination of ITS and cox1 were suitable for the molecular identification of G. vermiculophylla Germplasm.