海带栽培品系和长海带ITS区的PCR扩增及序列分析

对遗传背景清晰且具有显著表型差异的海带6个栽培品系(CUL002，CUL860，CUL1170，CUE017，CUE018，CUL901)和长海带(L．longissia)的ITS区进行了PCR扩增和序列测定，并分析了8个种17个品系(其中7种共10株从GenBank中获得)海带之间的系统进化关系。结果表明：表型各异的6个海带栽培品系ITS区差别很小，其中ITS1 5．8S rDNA序列完全相同，部分品系间ITS2序列有个别碱基差异；进化树显示与日本海带(L．japonica，AF319018)聚在一起，相似性大于98％，其中CUL901、CUL860和CULll70的ITS序列完全相同。长海带(L．longissia)的ITS 5．8S rDNA和日本海带(L．japonica，AF319018)的完全相同。以Undaria peterseniana为外类群，根据ITS 5．8S rDNA序列构建进化树，6栽培品系及长海带与日本海带聚在一起；17株海带基本构成两个大的进化枝。研究结果揭示了我国海域栽培的长海带可能与日本海带(L．iaponica，AF319018)为同一个种。

PCR amplification and sequence analysis of ITS regions ofcultivated Laminaria strains and L. Longissima

The internal transcribed spacer (ITS) regions of nuclear ribosomal DNA (including 5.8 S rDNA) of 6 cultivated Laminaria strains (CUL002, CUL860, CUL1170, CUL901, CUL018) with a clear genetic background and variant phenotype and L. longissima living in Chinese sea area were amplified and sequenced. The obtained ITS sequences including 5.8 S rDNA amplified by polymerase chain reaction (PCR) were conformed by NCBI BLAST. The phylogenetic relationships of 7 sequenced ITS sequences together with that of 10 selected strains (representing 7 Laminaria species) and Undaria peterseniana downloaded from GenBank were constructed. Undaria peterseniana was designated as outgroup. The result indicated that: (1) There was little diversity in ITS regions of 6 cultivated Laminaria strains. The ITS1+5 8 S rDNA sequences were exactly the same as that of L. Japonica (AF319018, Japan), however, the ITS2 regions possessed individual variation. Futhermore, the ITS + 5 8 S rDNA sequences of CUL901, CUL860 and CUL1170 were identical. (2) The ITS and 5 8 S rDNA sequence of L. longissima was absolutely identical to that of L. japonica (AF319018, Japan), and it was supposed to be a variation of L. japonica. The ITS + 5.8 S rDNA-based phylogenetic tree showed that: 14 selected Laminaria strains were divided into 2 strongly-supported monophyletic clades.