Evolutionary history of phycoerythrin pigmentation in the water bloom-forming cyanobacterium Microcystis aeruginosa
Evolutionary history of phycoerythrin pigmentation in the water bloom-forming cyanobacterium Microcystis aeruginosa
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水华形成蓝藻铜绿微囊藻中藻红蛋白色素沉着的进化史
DOI：
10.1101/485508
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Haruyo Yamaguchi
中科院分区：
文献类型：
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作者：
Yuuhiko Tanabe;Haruyo Yamaguchi
铜绿微囊藻是一种在世界各地富营养化淡水和咸淡水水体中发现的形成水华的蓝藻。典型的蓝藻，大多数。铜绿菌的颜色是蓝绿色的，这是由于藻蓝蛋白（PC）和绿藻两种光合色素的共存。虽然不太常见，但M。由于另一种色素藻红蛋白（PE）的存在，铜绿杆菌呈褐色。然而，基因组基础，系统发育和进化起源的PE色素沉着在m。到目前为止，铜绿菌的特征还很差。在本研究中，我们对5个含pe的m的基因组进行了测序和表征。aeruginosastrains。推定的PE合成和调控基因（聚类）在所有五个测序基因组以及三个先前发表的dm中被鉴定出来。aeruginosagenomes。值得注意的是，吸收光谱表明，PE含量，而不是PC含量，在所有含PE的菌株中，对红/绿光的可用性有明显的响应。这与ccas /ccaR的存在是一致的，ccas /ccaR是II型彩色适配器的标志。核心基因组基因的系统发育分析表明，pe基因型分布在3个不同的系统发育群中。相比之下，无论基因组背景如何，集群的基因组组织大多是保守的。此外，PE基因的系统发育发现是一致的，与核心基因组系统发育一致。对核心基因组和PE基因的比较显示，两个含PE群体之间的遗传差异水平相似。这些结果表明，负责PE色素沉着的基因被引入了tom。铜绿菌在进化早期出现，此后可能由于生态适应而反复丢失。后来在进化过程中额外的水平基因转移（HGT）也促成了PE inM目前的系统发育分布。绿脓杆菌。
Microcystis aeruginosais a bloom-forming cyanobacterium found in eutrophic fresh-and brackish water bodies worldwide. As typical for cyanobacteria, mostM. aeruginosastrains are blue-green in color owing to the concomitance of two photosynthetic pigments, phycocyanin (PC) and chlorophylla. Although less common,M. aeruginosastrains that are brownish in color owing to the presence of another pigment phycoerythrin (PE) have been documented. However, the genomic basis, phylogeny, and evolutionary origin of PE pigmentation inM. aeruginosahave only been poorly characterized until date. In the present study, we sequenced and characterized the genomes of five PE-containingM. aeruginosastrains. Putative PE synthesis and regulation genes (thecpecluster) were identified in all five sequenced genomes as well as in three previously publishedM. aeruginosagenomes. Of note, Absorption spectra indicated that the PE content, but not PC content, was markedly altered in response to availability of red/green light in all PE-containing strains. This was consistent with the presence ofccaS/ccaR, a hallmark of type II chromatic adapter, in thecpecluster. Phylogenetic analyses of core genome genes indicated that PE-containing genotypes were located in three different phylogenetic groups. In contrast, the genomic organization of thecpecluster was mostly conserved regardless of genomic background. Additionally, the phylogenies of PE genes were found to be congruent, consistent with the core genome phylogeny. A comparison of core genome and PE genes showed a similar level of genetic divergence between two PE-containing groups. These results suggest that genes responsible for PE pigmentation were introduced intoM. aeruginosaearly during evolution and were repeatedly lost thereafter possibly due to ecological adaptation. Additional horizontal gene transfer (HGT) later during evolution also contributed to the present phylogenetic distribution of PE inM. aeruginosa.