| Abstract | Marine picocyanobacteria, Prochlorococcus and Synechococcus, substantially contribute to marine primary production and have been the subject of extensive ecological and genomic studies. Little is known about their close relatives from freshwater and non-marine environments. Phylogenomic analyses (using 136 proteins) provide strong support for the monophyly of a clade of non-marine picocyanobacteria consisting of Cyanobium, Synechococcus and marine Sub-cluster 5.2; this clade itself is sister to marine Synechococcus and Prochlorococcus. The most basal lineage within the Syn/Pro clade, Sub-Cluster 5.3, includes marine and freshwater strains. Relaxed molecular clock (SSU, LSU) analyses show that while ancestors of the Syn/Pro clade date as far back as the end of the Pre-Cambrian, modern crown groups evolved during the Carboniferous and Triassic. Comparative genomic analyses reveal novel gene cluster arrangements involved in phycobilisome (PBS) metabolism in freshwater strains. Whilst PBS genes in marine Synechococcus are mostly found in one type of phycoerythrin (PE) rich gene cluster (Type III), strains from non-marine habitats, so far, appear to be more diverse both in terms of pigment content and gene arrangement, likely reflecting a wider range of habitats. Our phylogenetic analyses show that the PE genes (mpeBA) evolved via a duplication of the cpeBA genes in an ancestor of the marine and non-marine picocyanobacteria and of the symbiotic strains Synechococcus spongiarum. A primitive Type III-like ancestor containing cpeBA and mpeBA had thus evolved prior to the divergence of the Syn/Pro clade and S. spongiarum. During the diversification of Synechococcus lineages, losses of mpeBA genes may explain the emergence of pigment cluster Types I, II, IIB, and III in both marine and non-marine habitats, with few lateral gene transfer events in specific taxa. Copyright: CC BY 4.0 |
| Text | 420937 2019 10.3389/fmicb.2019.00045.s001 Scopus 2 s2.0 85062357623 ISI Web of Science WOS DATA2019093015842947 picocyanobacteria Synechococcus Cyanobium phycobilisomes phylogenomics comparative genomics phycoerythrin Microbiology microbial genetics microbial ecology mycology picocyanobacteria Synechococcus Cyanobium Phycobilisomes Phylogenomics Comparative genomics Phycoerythrin picocyanobacteria Synechococcus picocyanobacteria Synechococcus Cyanobium phycobilisomes phylogenomics comparative genomics phycoerythrin Insights Into the Evolution of Picocyanobacteria and Phycoerythrin Genes mpeBA and cpeBA Sanchez Baracaldo, Patricia; Bianchini, Giorgio; Di Cesare, Andrea; Callieri, Cristiana; Chrismas, Nathan AM School of Geographical Sciences, University of Bristol, Bristol, United Kingdom; Institute of Ecosystem Study ISE , Water Research Institute IRSA Consiglio Nazionale delle Ricerche, Verbania, Italy; Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy; Marine Biological Association of the United Kingdom, Citadel Hill, Plymouth, United Kingdom Marine picocyanobacteria, Prochlorococcus and Synechococcus, substantially contribute to marine primary production and have been the subject of extensive ecological and genomic studies. Little is known about their close relatives from freshwater and non marine environments. Phylogenomic analyses using 136 proteins provide strong support for the monophyly of a clade of non marine picocyanobacteria consisting of Cyanobium, Synechococcus and marine Sub cluster 5.2; this clade itself is sister to marine Synechococcus and Prochlorococcus. The most basal lineage within the Syn/Pro clade, Sub Cluster 5.3, includes marine and freshwater strains. Relaxed molecular clock SSU, LSU analyses show that while ancestors of the Syn/Pro clade date as far back as the end of the Pre Cambrian, modern crown groups evolved during the Carboniferous and Triassic. Comparative genomic analyses reveal novel gene cluster arrangements involved in phycobilisome PBS metabolism in freshwater strains. Whilst PBS genes in marine Synechococcus are mostly found in one type of phycoerythrin PE rich gene cluster Type III , strains from non marine habitats, so far, appear to be more diverse both in terms of pigment content and gene arrangement, likely reflecting a wider range of habitats. Our phylogenetic analyses show that the PE genes mpeBA evolved via a duplication of the cpeBA genes in an ancestor of the marine and non marine picocyanobacteria and of the symbiotic strains Synechococcus spongiarum. A primitive Type III like ancestor containing cpeBA and mpeBA had thus evolved prior to the divergence of the Syn/Pro clade and S. spongiarum. During the diversification of Synechococcus lineages, losses of mpeBA genes may explain the emergence of pigment cluster Types I, II, IIB, and III in both marine and non marine habitats, with few lateral gene transfer events in specific taxa. Copyright CC BY 4.0 Marine picocyanobacteria, Prochlorococcus and Synechococcus, substantially contribute to marine primary production and have been the subject of extensive ecological and genomic studies. Little is known about their close relatives from freshwater and non marine environments. Phylogenomic analyses using 136 proteins provide strong support for the monophyly of a clade of non marine picocyanobacteria consisting of Cyanobium, Synechococcus and marine Sub cluster 5.2; this clade itself is sister to marine Synechococcus and Prochlorococcus. The most basal lineage within the Syn/Pro clade, Sub Cluster 5.3, includes marine and freshwater strains. Relaxed molecular clock SSU, LSU analyses show that while ancestors of the Syn/Pro clade date as far back as the end of the Pre Cambrian, modern crown groups evolved during the Carboniferous and Triassic. Comparative genomic analyses reveal novel gene cluster arrangements involved in phycobilisome PBS metabolism in freshwater strains. Whilst PBS genes in marine Synechococcus are mostly found in one type of phycoerythrin PE rich gene cluster Type III , strains from non marine habitats, so far, appear to be more diverse both in terms of pigment content and gene arrangement, likely reflecting a wider range of habitats. Our phylogenetic analyses show that the PE genes mpeBA evolved via a duplication of the cpeBA genes in an ancestor of the marine and non marine picocyanobacteria and of the symbiotic strains Synechococcus spongiarum. A primitive Type III like ancestor containing cpeBA and mpeBA had thus evolved prior to the divergence of the Syn/Pro clade and S. spongiarum. During the diversification of Synechococcus lineages, losses of mpeBA genes may explain the emergence of pigment cluster Types I, II, IIB, and III in both marine and non marine habitats, with few lateral gene transfer events in specific taxa. 10 Published version http //www.scopus.com/record/display.url eid=2 s2.0 85062357623 origin=inward Insights Into the Evolution of Picocyanobacteria and Phycoerythrin Genes mpeBA and cpeBA fmicb 10 00045.pdf Articolo in rivista Frontiers Research Foundation, 1664 302X Frontiers in microbiology Frontiers in microbiology Front. microbiol. Frontiers in microbiology cristiana.callieri CALLIERI CRISTIANA andrea.dicesare DI CESARE ANDREA |
