Systematics And Biogeography Of Bangiaceaen Algae From China Based On The RbcL Sequences

The systematics of Bangiacean algae was studied in this paper based on the 1, 5-biphosphate-ribulose carboxylase / oxygenase large subunit (rbcL) gene sequence. The study focused on the genus Porphyra and Bangia provided the systematic information for the global research of Bangiacean algae and offered molecular basis for taxonomy.It is the first time that the rbcL sequence was amplified, sequenced and analyzed of Bangia including four populations from coastline of China and one population from inland region. The results showed the length of rbcL sequences of Bangia from different regions were basically identity which was about 1400bp consistenting between freshwater and marine Bangia. The mean homology index of Bangia from Lvsi, Putian and Shantou was 99.5% which is a little larger than that between them and Bangia from Dongying as 98.3%. However, all of these varieties were within the variety range of intraspecies. Phylogeny trees showed marine Bangia from different regions were clusterd in the same calde suggested that there is at least one wide distribution species along coastline of China. The homology index between freshwater Bangia and marine Bangia was just 90.6% indicating large sequence variety between them. Moreover, freshwater Bangia from China was clustered closely with all of that from other regions of the world while distinct from marine Bangia of China. These evidences suggested that freshwater Bangia from China was a distinct species from marine Bangia. The results of phylogeny trees supported the opinion that freshwater Bangia have separated from marine Bangia for a long-term.rbcL gene was amplified and analyzed for the conchocelis phase of four common Porphyra species from China. Fourteen samples was studied and resolved as three main clades in phylogeny trees constructed based on rbcL sequences. The three clades were (1) clade of P. yezoensis and P. oligospermatangia; (2) clade of P. katadai var. hemiphylla and (3) clade of P. katadai var. hemiphylla and P. haitanensis. P. yezoensis and P. oligospermatangia were included in clade one which was consisted of two subclades. One subclade included only P. yezoensis and the other clade nested P. oligospermatangia with P. yezoensis. The third Clade was consisted of two subclades too which were consisted of P. haitanensis or P. haitanensis and P. katadai var. hemiphylla, respectively. In the subclade of P. yezoensis, samples of P. yezoensis from China were cluster together with samples from Japan and Korea. The general phylogeny trend showed by conchocelis materials even those stored for up to ten years was the same with the fresh materials.Forty-eight samples of thirteen species of Bangiacean algae were collected from coastline of China between 36°06′N and 23°25′N and one inland region (37°58′N, 113°53′E). The rbcL genes of these samples were amplified and sequenced. Forty sequences of the forty-eight samples were subjected to multi-alignment based on which the distance matrix was computed. Phylogenic trees were constructed based on the corrected sequences by NJ and ME methods with MEGA 2.0. Both of the trees resolved four main clades: (1) clade consisted of P. katadai var. hemiphylla, Porphyra haitanensis,P. crispata and P. dentata; (2) clade of Bangia from coastline and inland regions; (3) clade of P. yezoensis and P. oligospermatangia; (4) clade of P. suborbiculata. The results showed P. ishigecola was nested with P. suborbiculata, collected from different latitude, with bootstrap value as 99% and both of them have similar morphology. Although P. dentata and P. haitanensis, collected from the same region, were clustered together in one clade and morphological similitude, they located different phylogenic position and should be two species.'P. yezoensis'and'P. oligospermatangia', collected from nearby regions of 36°N, were clustered with typical samples of P. yezoensis and P. oligospermatangia respectively. Phylogenic trees were constructed based on sequences obtained and downloaded from GenBank with defining species. The distribution of Bangiacean algae from China in the important evolutionary phases of the phylogenic tree was discussed.