Analysis of mechanisms of reproductive isolation and speciation in unicellular conjugatophycean Closterium.

单细胞共轭藻新月生殖隔离和物种形成机制分析。

基本信息

批准号：
17405013
负责人：
SEKIMOTO Hiroyuki
金额：
$ 7.46万
依托单位：
Japan Women's University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

The Closterium peracerosum-strigosum-littorale complex (C. pslc) is a unicellular alga, and is known to be composed of several reproductively isolated mating groups of heterothallic strains. We have carried out field studies in 8 prefectures such as Tokyo, Ibaraki, Saitama, Nagano, Hiroshima, Yamaguchi, Okinawa, and Shizuoka in Japan, and in five foreign countries such as Germany, Taiwan, New Zealand, Slovakia, and Indonesia, to isolate reproductively isolated C. pslc. Finally, we have established 43 clones from these fields.We have studied phylogenetic relationship using DNA sequences of 1506 group I introns of these clones. Based on the alignment, significant phylogenetic relationships were observed among mating groups II-A and II-B, while mating group I-E was distant from groups II-A and II-B. Indeed, mating group I-E is completely sexually isolated from mating groups II-A and II-B, groups II-A and II-B are partially isolated from each other, and only mating-type plus (mt^+) cells of group II-A and mating-type minus (mt^-) cells of group II-B form zygotes. Sexual cell division in both mating-type cells of group A was stimulated in conditioned media in which cells of group II-B had been cultured. When mt^- cells of group II-B were stimulated in conditioned medium derived from group II-A, mt^+ cells of group II-B did not respond to the conditioned medium. Conditioned media derived from group D did not exhibit SCD-inducing activity against any strain except those within its own group. From the alignment of deduced amino acid sequences from orthologous PR-IP Inducer genes, we detected a significant similarity among groups A and B., and mating group D had low similarity to other mating groups. The existing degree of reproductive isolation can be partially explained by differences in molecular structures and physiological activities of sex pheromones of these heterothallic mating groups.

闭叶毛 - 甲状腺膜状植物复合物（C. pslc）是一种单细胞藻类，已知由几个生殖分离的杂质菌株组成。我们已经在日本的东京，伊巴拉基，西塔玛，内加诺，山岛，山古岛，山口，冲绳和shizuoka等8个州进行了现场研究，以及在德国，台湾，新西兰，斯洛瓦基亚，斯洛瓦基亚，印度尼西亚，以及分离彼此的隔离c. psslc C. psledcclc。最后，我们已经从这些领域建立了43个克隆。我们使用了这些克隆的1506组内含子的DNA序列研究了系统发育关系。基于比对，在II-A和II-B组中观察到了显着的系统发育关系，而交配I-E组远离II-A组和II-B组。实际上，I-E组完全从II-A和II-B组中完全分离出性别分离，II-A和II-B组彼此部分分离，仅配合II-A组的交配型Plus（MT^+）细胞（MT^+）细胞，以及II-B组的II-B组细胞（MT^ - ）细胞形成Zygotes。在条件培养基中刺激了A组A组的两个交配型细胞中的性细胞分裂，其中已培养了II-B组细胞。当在衍生自II-A组的条件培养基中刺激II-B组的MT^ - 细胞时，II-B组的MT^+细胞对条件培养基没有反应。从D组得出的条件培养基没有针对任何菌株表现出SCD诱导活性，除了其本体中的菌株。从直系同源PR-IP诱导剂基因的推导氨基酸序列的比对，我们检测到A组和B组之间的显着相似性，而D组D组与其他交配组的相似性很低。现有的生殖隔离程度可以部分通过这些异性交配组的性信息素的分子结构和生理活性的差异来解释。