Yokoyama Akiko, Takahashi Fumio, Kataoka Hironao, Hara Yoshiaki, Nozaki Hisayoshi
Graduate School of Science and Engineering, Yamagata University, Kojirakawa 1-4-12, Yamagata 990-8560, Japan Graduate School of Life Sciences, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 Japan Department of Biology, Faculty of Science, Yamagata University, Kojirakawa 1-4-12, Yamagata 990-8560, Japan Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
J Phycol. 2011 Apr;47(2):407-14. doi: 10.1111/j.1529-8817.2011.00961.x. Epub 2011 Mar 30.
Although the dinophytes generally possess red-algal-derived secondary plastids, tertiary plastids originating from haptophyte and diatom ancestors are recognized in some lineages within the Dinophyta. However, little is known about the nuclear-encoded genes of plastid-targeted proteins from the dinophytes with diatom-derived tertiary plastids. We analyzed the sequences of the nuclear psbO gene encoding oxygen-evolving enhancer protein from various algae with red-algal-derived secondary and tertiary plastids. Based on our sequencing of 10 new genes and phylogenetic analysis of PsbO amino acid sequences from a wide taxon sampling of red algae and organisms with red-algal-derived plastids, dinophytes form three separate lineages: one composed of peridinin-containing species with secondary plastids, and the other two having haptophyte- or diatom-derived tertiary plastids and forming a robust monophyletic group with haptophytes and diatoms, respectively. Comparison of the N-terminal sequences of PsbO proteins suggests that psbO genes from a dinophyte with diatom-derived tertiary plastids (Kryptoperidinium) encode proteins that are targeted to the diatom plastid from the endosymbiotic diatom nucleus as in the secondary phototrophs, whereas the fucoxanthin-containing dinophytes (Karenia and Karlodinium) have evolved an additional system of psbO genes for targeting the PsbO proteins to their haptophyte-derived tertiary plastids from the host dinophyte nuclei.
虽然甲藻通常拥有源自红藻的次生质体，但在甲藻门的一些谱系中也发现了源自定鞭藻和硅藻祖先的三生质体。然而，对于具有硅藻衍生三生质体的甲藻中质体靶向蛋白的核编码基因，我们了解甚少。我们分析了编码放氧增强蛋白的核psbO基因的序列，这些基因来自具有红藻衍生次生和三生质体的各种藻类。基于我们对10个新基因的测序以及对红藻和具有红藻衍生质体的生物的广泛分类样本中PsbO氨基酸序列的系统发育分析，甲藻形成了三个独立的谱系：一个由含有二甲基丙烯酰基叶绿素a的具有次生质体的物种组成，另外两个具有源自定鞭藻或硅藻的三生质体，分别与定鞭藻和硅藻形成一个强大的单系类群。对PsbO蛋白N端序列的比较表明，具有硅藻衍生三生质体的甲藻（隐甲藻）的psbO基因编码的蛋白，如同次生光合生物一样，是从内共生硅藻细胞核靶向到硅藻质体的，而含有岩藻黄质的甲藻（卡伦藻和卡氏藻）已经进化出了一个额外的psbO基因系统，用于将PsbO蛋白从宿主甲藻细胞核靶向到它们源自定鞭藻的三生质体。
