A novel salt-tolerant genotype illuminates the sucrose gene evolution in freshwater bloom-forming cyanobacterium Microcystis aeruginosa

2019 ◽  
Vol 366 (15) ◽  
Author(s):  
Yuuhiko Tanabe ◽  
Haruyo Yamaguchi ◽  
Tomoharu Sano ◽  
Masanobu Kawachi
Keyword(s):  
Microcystis Aeruginosa ◽  
Brackish Water ◽  
Evolutionary History ◽  
Gene Evolution ◽  
Water Bloom ◽  
Salt Tolerant ◽  
Whole Genome Analysis ◽  
Gene Expression Analyses ◽  
History Of ◽  
Water Ecosystems

ABSTRACT Microcystis aeruginosa is a water bloom-forming cyanobacterium found in fresh and brackish water ecosystems worldwide. Previously, we showed that several instances of M. aeruginosa bloom in brackish water can be explained by the proliferation of salt-tolerant M. aeruginosa strains harboring genes for a compatible solute sucrose. However, evolutionary history of sucrose genes in M. aeruginosa remains unclear because salt-tolerant strains have been poorly described. Here, we characterized a novel salt-tolerant strain of M. aeruginosa (NIES-4325) isolated from the brackish water of Lake Abashiri, Japan. A whole-genome analysis of M. aeruginosa NIES-4325 identified genes for sucrose synthesis (sppA, spsA and susA). Quantitative sucrose and gene expression analyses suggested that sucrose is implicated in acclimation to high salt in NIES-4325. Notably, the sucrose genes of M. aeruginosa are monophyletic, yet sucrose genes of NIES-4325 are highly divergent from those of other salt-tolerant M. aeruginosa strains. This suggests an early sucrose gene import into M. aeruginosa from other cyanobacteria, followed by multiple losses during intraspecific diversification. One of a few survivors of salt-tolerant strains is a likely donor of recent horizontal spreads of sucrose genes across M. aeruginosa lineages.

scholarly journals Evolutionary history of phycoerythrin pigmentation in the water bloom-forming cyanobacteriumMicrocystis aeruginosa

2018 ◽  
Author(s):  
Yuuhiko Tanabe ◽  
Haruyo Yamaguchi
Keyword(s):  
Evolutionary History ◽  
Core Genome ◽  
Genomic Organization ◽  
Phylogenetic Analyses ◽  
Green Light ◽  
Water Bloom ◽  
Phylogenetic Groups ◽  
Genome Phylogeny ◽  
History Of ◽  
Genomic Basis

AbstractMicrocystis 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.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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