Sekimoto Hiroyuki
Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo, 112-8681, Japan.
J Plant Res. 2017 May;130(3):423-431. doi: 10.1007/s10265-017-0908-6. Epub 2017 Feb 10.
The sexual reproductive processes of some representative freshwater green algae are reviewed. Chlamydomonas reinhardtii is a unicellular volvocine alga having two mating types: mating type plus (mt) and mating type minus (mt), which are controlled by a single, complex mating-type locus. Sexual adhesion between the gametes is mediated by sex-specific agglutinin molecules on their flagellar membranes. Cell fusion is initiated by an adhesive interaction between the mt and mt mating structures, followed by localized membrane fusion. The loci of sex-limited genes and the conformation of sex-determining regions have been rearranged during the evolution of volvocine algae; however, the essential function of the sex-determining genes of the isogamous unicellular Chlamydomonas reinhardtii is conserved in the multicellular oogamous Volvox carteri. The sexual reproduction of the unicellular charophycean alga, Closterium peracerosum-strigosum-littorale complex, is also focused on here. The sexual reproductive processes of heterothallic strains are controlled by two multifunctional sex pheromones, PR-IP and PR-IP Inducer, which independently promote multiple steps in conjugation at the appropriate times through different induction mechanisms. The molecules involved in sexual reproduction and sex determination have also been characterized.
本文综述了一些具有代表性的淡水绿藻的有性生殖过程。莱茵衣藻是一种单细胞团藻目绿藻，有两种交配型：正交配型（mt⁺）和负交配型（mt⁻），由一个单一的、复杂的交配型基因座控制。配子之间的性黏附由其鞭毛膜上的性别特异性凝集素分子介导。细胞融合由mt⁺和mt⁻交配结构之间的黏附相互作用引发，随后是局部膜融合。在团藻目藻类的进化过程中，性别限制基因的位点和性别决定区域的构象发生了重排；然而，同配的单细胞莱茵衣藻的性别决定基因的基本功能在多细胞卵配的卡特氏团藻中得以保留。本文还重点介绍了单细胞轮藻目绿藻纤细新月藻复合体的有性生殖过程。异宗配合菌株的有性生殖过程由两种多功能性信息素PR-IP和PR-IP诱导物控制，它们通过不同的诱导机制在适当的时候独立促进接合过程中的多个步骤。参与有性生殖和性别决定的分子也已得到表征。
