Cyanobacterial genes transmitted to the nucleus before divergence of red algae in the chromista
Cyanobacterial genes transmitted to the nucleus before divergence of red algae in the chromista
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DOI：
10.1007/s00239-003-2611-1
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发表时间：
2004-07-01
影响因子：
3.9
通讯作者：
Kuroiwa, T
中科院分区：
文献类型：
--
作者：
Nozaki, H;Matsuzaki, M;Kuroiwa, T
红藻、绿色植物和蓝绿藻的质体可能通过原生内共生直接起源于类蓝藻原核生物。相反，真核光养生物的其他谱系的质体似乎是涉及光养真核生物和真核宿主细胞的二级或三级内共生事件的结果。虽然已经进行了系统发育分析的多个质体基因从广泛的真核生物谱系，系统发育位置的次生质体的Chromista（Heterokontophyta，Haptophyta和Cryptophyta）是模糊的，在一系列不同的分析。这种不确定性可能是由次生内共生所建立的质体基因中不寻常的取代或偏差的结果。在这项研究中，我们进行了系统发育分析的蓝藻起源的5个核基因（6-磷酸葡萄糖酸脱氢酶[gnd]，氧释放增强剂[psbO]，磷酸甘油酸激酶[pgk]，δ-氨基乙酰丙酸脱氢酶[aladh]，和ATP合成酶γ [atpC]基因），使用原始的红色蓝藻Cyanidioschyzon merolae 10 D的基因组序列数据。序列数据有力地解决了在现存红藻（包括紫菜[红藻科]和Cyanidioschyzon [Cyadidiophyceae]）分化之前，Chromista（Heterokontophyta和Haptophyta）和Dinophyta的细胞核中的蓝藻基因的起源。虽然这是可能的gnd基因在Chromista的传递从蓝藻类祖先的质体在初级内共生，其他基因可能已经转移从细胞核的红藻祖先在次级内共生。因此，这些结果表明，Chromista可能起源于现存红藻分化之前的古老次生内共生。
The plastids of red algae, green plants, and glaucophytes may have originated directly from a cyanobacterium-like prokaryote via primary endosymbiosis. In contrast, the plastids of other lineages of eukaryotic phototrophs appear to be the result of secondary or tertiary endosymbiotic events involving a phototrophic eukaryote and a eukaryotic host cell. Although phylogenetic analyses of multiple plastid genes from a wide range of eukaryotic lineages have been carried out, the phylogenetic positions of the secondary plastids of the Chromista (Heterokontophyta, Haptophyta and Cryptophyta) are ambiguous in a range of different analyses. This ambiguity may be the result of unusual substitutions or bias in the plastid genes established by the secondary endosymbiosis. In this study, we carried out phylogenetic analyses of five nuclear genes of cyanobacterial origin (6-phosphogluconate dehydrogenase [gnd], oxygen-evolving-enhancer [psbO], phosphoglycerate kinase [pgk], delta-aminolevulinic acid dehydratase [aladh], and ATP synthase gamma [atpC] genes), using the genome sequence data from the primitive red alga Cyanidioschyzon merolae 10D. The sequence data robustly resolved the origin of the cyanobacterial genes in the nuclei of the Chromista (Heterokontophyta and Haptophyta) and Dinophyta, before the divergence of the extant red algae (including Porphyra [Rhodophyceae] and Cyanidioschyzon [Cyadidiophyceae]). Although it is likely that gnd genes in the Chromista were transmitted from the cyanobacterium-like ancestor of plastids in the primary endosymbiosis, other genes might have been transferred from nuclei of a red algal ancestor in the secondary endosymbiosis. Therefore, the results indicate that the Chromista might have originated from the ancient secondary endosymblosis before the divergence of extant red algae.