TY  - JOUR
A1  - Burgsdorf, Ilia
A1  - Slaby, Beate M.
A1  - Handley, Kim M.
A1  - Haber, Markus
A1  - Blom, Jochen
A1  - Marshall, Christopher W.
A1  - Gilbert, Jack A.
A1  - Hentschel, Ute
A1  - Steindler, Laura
T1  - Lifestyle Evolution in Cyanobacterial Symbionts of Sponges
JF  - mBio
N2  - The "Candidatus Synechococcus spongiarum" group includes different clades of cyanobacteria with high 16S rRNA sequence identity (~99%) and is the most abundant and widespread cyanobacterial symbiont of marine sponges. The first draft genome of a "Ca. Synechococcus spongiarum" group member was recently published, providing evidence of genome reduction by loss of genes involved in several nonessential functions. However, "Ca. Synechococcus spongiarum" includes a variety of clades that may differ widely in genomic repertoire and consequently in physiology and symbiotic function. Here, we present three additional draft genomes of "Ca. Synechococcus spongiarum," each from a different clade. By comparing all four symbiont genomes to those of free-living cyanobacteria, we revealed general adaptations to life inside sponges and specific adaptations of each phylotype. Symbiont genomes shared about half of their total number of coding genes. Common traits of "Ca. Synechococcus spongiarum" members were a high abundance of DNA modification and recombination genes and a reduction in genes involved in inorganic ion transport and metabolism, cell wall biogenesis, and signal transduction mechanisms. Moreover, these symbionts were characterized by a reduced number of antioxidant enzymes and low-weight peptides of photosystem II compared to their free-living relatives. Variability within the "Ca. Synechococcus spongiarum" group was mostly related to immune system features, potential for siderophore-mediated iron transport, and dependency on methionine from external sources. The common absence of genes involved in synthesis of residues, typical of the O antigen of free-living Synechococcus species, suggests a novel mechanism utilized by these symbionts to avoid sponge predation and phage attack. 

IMPORTANCE 
While the Synechococcus/Prochlorococcus-type cyanobacteria are widely distributed in the world's oceans, a subgroup has established its niche within marine sponge tissues. Recently, the first genome of sponge-associated cyanobacteria, " Candidatus Synechococcus spongiarum," was described. The sequencing of three representatives of different clades within this cyanobacterial group has enabled us to investigate intraspecies diversity, as well as to give a more comprehensive understanding of the common symbiotic features that adapt "Ca. Synechococcus spongiarum" to its life within the sponge host.
KW  - marine Synechococcus strains
KW  - ribosomal RNA genes
KW  - single cell
KW  - vertical transmission
KW  - microbial communities
KW  - sequence analysis
KW  - spacer sequences
KW  - genomic analysis
KW  - web server
KW  - reveals
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143117
VL  - 6
IS  - 3
ER  - 
TY  - JOUR
A1  - Schartl, Manfred
A1  - Walter, Ronald B.
A1  - Shen, Yingjia
A1  - Garcia, Tzintzuni
A1  - Catchen, Julian
A1  - Amores, Angel
A1  - Braasch, Ingo
A1  - Chalopin, Domitille
A1  - Volff, Jean-Nicolas
A1  - Lesch, Klaus-Peter
A1  - Bisazza, Angelo
A1  - Minx, Pat
A1  - Hillier, LaDeana
A1  - Wilson, Richard K.
A1  - Fürstenberg, Susan
A1  - Boore, Jeffrey
A1  - Searle, Steve
A1  - Postlethwait, John H.
A1  - Warren, Wesley C.
T1  - The genome of the platyfish, Xiphophorus maculatus, provides insights into evolutionary adaptation and several complex traits
JF  - Nature Genetics
N2  - Several attributes intuitively considered to be typical mammalian features, such as complex behavior, live birth and malignant disease such as cancer, also appeared several times independently in lower vertebrates. The genetic mechanisms underlying the evolution of these elaborate traits are poorly understood. The platyfish, X. maculatus, offers a unique model to better understand the molecular biology of such traits. We report here the sequencing of the platyfish genome. Integrating genome assembly with extensive genetic maps identified an unexpected evolutionary stability of chromosomes in fish, in contrast to in mammals. Genes associated with viviparity show signatures of positive selection, identifying new putative functional domains and rare cases of parallel evolution. We also find that genes implicated in cognition show an unexpectedly high rate of duplicate gene retention after the teleost genome duplication event, suggesting a hypothesis for the evolution of the behavioral complexity in fish, which exceeds that found in amphibians and reptiles.
KW  - genomics
KW  - genomic analysis
KW  - evolutionary biology
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-132152
VL  - 45
IS  - 5
ER  -