一株淡水红藻的形态及分子系统发育研究

摘要

以采自山西晋祠泉的一株淡水红藻JC1712001为实验材料, 对其进行分子系统发育分析和形态特征鉴定, 同时利用分子数据对其进行生物地理学研究.结果显示, 该株淡水红藻JC1712001与美国、西班牙地区报道的马赫拉熊野藻 (Kumanoa mahlacensis Kumano) 遗传距离最近, 基于rbc L、COI和UPA序列的遗传距离均为0.基于3个序列, 利用贝叶斯法、最大似然法和邻接法3种方法构建的系统发育树具有高度一致的系统发育关系, JC1712001均与西班牙及美国地区已报道的马赫拉熊野藻聚为一支, 支持率都在97％以上, 支持其为马赫拉熊野藻, 同时也表明3个基因的高度保守性.形态特征的观察也支持这个结果.马赫拉熊野藻在欧洲、亚洲、北美洲均有分布, RASP软件构建的地理起源图谱显示, 欧洲类群地理起源更为古老.马赫拉熊野藻为稀有种, 本文的研究结果丰富了我国淡水红藻的分布, 为其系统发育和地理起源研究提供了依据.%The molecular analysis and morphological identification of a freshwater red alga JC1712001, collected from Jinci spring, Shanxi Province, North China, were performed, and its biogeographic analysis was conducted using molecular biological evidence.The results showed that the genetic distances between JC1712001 and Kumanoa mahlacensis Kumano strains from the United States and Spanish were all 0 based on the rbc L, COI and UPA sequences, indicating that the three genes were highly conserved. Phylogenetic trees based on three sequences by three methods, including Bayesian method, maximum likelihood method and neighboring method, were highly consistent. In the phylogenetic trees, JC1712001 were clustered with K. mahlensis from Spain and the United States, and the support rates were all above 97％. According to molecular biological evidence, JC1712001 is also classified as K.mahlensis. The geographical origin map constructed by RASP software showed that K. mahlensis was distributed in Europe, Asia, and North America, and the origin of European group is more ancient. K. mahlensis is a rare species, and the results of this study have enriched the distribution of freshwater red algae in China. Meanwhile, it also provided data for the phylogenetic analysis and the geographical origin research.