Origins of a cyanobacterial 6-phosphogluconate dehydrogenase in plastid-lacking eukaryotes.
Origins of a cyanobacterial 6-phosphogluconate dehydrogenase in plastid-lacking eukaryotes.
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DOI：
10.1186/1471-2148-8-151
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发表时间：
2008-05-17
影响因子：
3.4
通讯作者：
Nozaki H
中科院分区：
文献类型：
--
作者：
Maruyama S;Misawa K;Iseki M;Watanabe M;Nozaki H
蓝藻是从一个单一的蓝藻祖先那里继承了自己的基因组，但大多数蓝藻基因一旦保留在祖先的质体基因组中，就会丢失或通过内共生基因转移到真核宿主核基因组中。虽然先前的研究表明，蓝藻GND基因编码6-磷酸葡萄糖酸脱氢酶，存在于几个缺乏叶绿体的原生生物以及初级和次生的光养真核生物中，但这些基因的进化路径仍然不清楚。在这里，我们展示了一个扩展的系统发育分析，包括新的来自洞穴门和格劳藻门的GND基因序列。我们的分析证明了所挖掘的基因在GND基因系统发育中的斑块分布。Diplonema基因与红藻和后丝藻中的胞溶体型基因有亲缘关系，而异叶藻基因与胞质型红藻基因在单系真核生物群中占据了基本的系统发育位置，与蓝藻基因是姊妹种。基于穷尽最大似然分析的统计检验强烈否定了异叶型GND基因来自绿色系次生体的说法。此外，裸藻纲中光养和吞噬两种蓝藻的GND基因与稻纵卷藻有较强的单系同源性，与红藻的GND基因有一定程度的分离。这些数据表明，这些次生光营养群可能已经获得了不依赖于次生内生共生的蓝藻基因。我们提出了一种进化情景，即在真核生物进化的早期，缺乏叶绿体的Exavata通过真核生物到真核生物的侧向基因转移或初级内共生基因转移获得蓝藻GND基因，然后失去原有的或蓝藻基因。
Plastids have inherited their own genomes from a single cyanobacterial ancestor, but the majority of cyanobacterial genes, once retained in the ancestral plastid genome, have been lost or transferred into the eukaryotic host nuclear genome via endosymbiotic gene transfer. Although previous studies showed that cyanobacterial gnd genes, which encode 6-phosphogluconate dehydrogenase, are present in several plastid-lacking protists as well as primary and secondary plastid-containing phototrophic eukaryotes, the evolutionary paths of these genes remain elusive. Here we show an extended phylogenetic analysis including novel gnd gene sequences from Excavata and Glaucophyta. Our analysis demonstrated the patchy distribution of the excavate genes in the gnd gene phylogeny. The Diplonema gene was related to cytosol-type genes in red algae and Opisthokonta, while heterolobosean genes occupied basal phylogenetic positions with plastid-type red algal genes within the monophyletic eukaryotic group that is sister to cyanobacterial genes. Statistical tests based on exhaustive maximum likelihood analyses strongly rejected that heterolobosean gnd genes were derived from a secondary plastid of green lineage. In addition, the cyanobacterial gnd genes from phototrophic and phagotrophic species in Euglenida were robustly monophyletic with Stramenopiles, and this monophyletic clade was moderately separated from those of red algae. These data suggest that these secondary phototrophic groups might have acquired the cyanobacterial genes independently of secondary endosymbioses. We propose an evolutionary scenario in which plastid-lacking Excavata acquired cyanobacterial gnd genes via eukaryote-to-eukaryote lateral gene transfer or primary endosymbiotic gene transfer early in eukaryotic evolution, and then lost either their pre-existing or cyanobacterial gene.
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影响因子：
3.4
作者：
Marin B;Nowack EC;Glöckner G;Melkonian M
通讯作者：
Melkonian M
影响因子：
56.9
作者：
Armbrust, EV;Berges, JA;Rokhsar, DS
通讯作者：
Rokhsar, DS
影响因子：
64.8
作者：
Matsuzaki, M;Misumi, O;Kuroiwa, T
通讯作者：
Kuroiwa, T
影响因子：
3.5
作者：
Henze, K;Horner, DS;Embley, TM
通讯作者：
Embley, TM
DOI：
10.1073/pnas.182432999
发表时间：
2002-09-17
影响因子：
11.1
作者：
Martin, W;Rujan, T;Penny, D
通讯作者：
Penny, D