TY - GEN A1 - Obbard, Darren J. A1 - Shi, Mang A1 - Roberts, Katherine E. A1 - Longdon, Ben A1 - Dennis, Alice B. T1 - A new lineage of segmented RNA viruses infecting animals T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Metagenomic sequencing has revolutionised our knowledge of virus diversity, with new virus sequences being reported faster than ever before. However, virus discovery from metagenomic sequencing usually depends on detectable homology: without a sufficiently close relative, so-called ‘dark’ virus sequences remain unrecognisable. An alternative approach is to use virus-identification methods that do not depend on detecting homology, such as virus recognition by host antiviral immunity. For example, virus-derived small RNAs have previously been used to propose ‘dark’ virus sequences associated with the Drosophilidae (Diptera). Here, we combine published Drosophila data with a comprehensive search of transcriptomic sequences and selected meta-transcriptomic datasets to identify a completely new lineage of segmented positive-sense single-stranded RNA viruses that we provisionally refer to as the Quenyaviruses. Each of the five segments contains a single open reading frame, with most encoding proteins showing no detectable similarity to characterised viruses, and one sharing a small number of residues with the RNA-dependent RNA polymerases of single- and double-stranded RNA viruses. Using these sequences, we identify close relatives in approximately 20 arthropods, including insects, crustaceans, spiders, and a myriapod. Using a more conserved sequence from the putative polymerase, we further identify relatives in meta-transcriptomic datasets from gut, gill, and lung tissues of vertebrates, reflecting infections of vertebrates or of their associated parasites. Our data illustrate the utility of small RNAs to detect viruses with limited sequence conservation, and provide robust evidence for a new deeply divergent and phylogenetically distinct RNA virus lineage. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1411 KW - metagenome KW - RNA virus KW - dark virus KW - arthropod KW - RNA interference Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-516040 SN - 1866-8372 IS - 1 ER - TY - GEN A1 - Paraskevopoulou, Sofia A1 - Dennis, Alice B. A1 - Weithoff, Guntram A1 - Tiedemann, Ralph T1 - Temperature-dependent life history and transcriptomic responses in heat-tolerant versus heat-sensitive Brachionus rotifers T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Thermal stress response is an essential physiological trait that determines occurrence and temporal succession in nature, including response to climate change. We compared temperature-related demography in closely related heat-tolerant and heat-sensitive Brachionus rotifer species. We found significant differences in heat response, with the heat-sensitive species adopting a strategy of long survival and low population growth, while the heat-tolerant followed the opposite strategy. In both species, we examined the genetic basis of physiological variation by comparing gene expression across increasing temperatures. Comparative transcriptomic analyses identified shared and opposing responses to heat. Interestingly, expression of heat shock proteins (hsps) was strikingly different in the two species and mirrored differences in population growth rates, showing that hsp genes are likely a key component of a species’ adaptation to different temperatures. Temperature induction caused opposing patterns of expression in further functional categories including energy, carbohydrate and lipid metabolism, and in genes related to ribosomal proteins. In the heat-sensitive species, elevated temperatures caused up-regulation of genes related to meiosis induction and post-translational histone modifications. This work demonstrates the sweeping reorganizations of biological functions that accompany temperature adaptation in these two species and reveals potential molecular mechanisms that might be activated for adaptation to global warming. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1012 KW - Ecology KW - Evolution KW - Oyster Crassostrea-gigas KW - cryptic species complex KW - pacific oyster KW - thermal-stress KW - genetic differentiation KW - expression patterns KW - molecular phylogeny KW - shock proteins KW - evolutionary KW - hsp70 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-482280 SN - 1866-8372 IS - 1012 ER - TY - GEN A1 - Dennis, Alice B. A1 - Ballesteros, Gabriel I. A1 - Robin, Stéphanie A1 - Schrader, Lukas A1 - Bast, Jens A1 - Berghöfer, Jan A1 - Beukeboom, Leo W. A1 - Belghazi, Maya A1 - Bretaudeau, Anthony A1 - Buellesbach, Jan A1 - Cash, Elizabeth A1 - Colinet, Dominique A1 - Dumas, Zoé A1 - Errbii, Mohammed A1 - Falabella, Patrizia A1 - Gatti, Jean-Luc A1 - Geuverink, Elzemiek A1 - Gibson, Joshua D. A1 - Hertaeg, Corinne A1 - Hartmann, Stefanie A1 - Jacquin-Joly, Emmanuelle A1 - Lammers, Mark A1 - Lavandero, Blas I. A1 - Lindenbaum, Ina A1 - Massardier-Galata, Lauriane A1 - Meslin, Camille A1 - Montagné, Nicolas A1 - Pak, Nina A1 - Poirié, Marylène A1 - Salvia, Rosanna A1 - Smith, Chris R. A1 - Tagu, Denis A1 - Tares, Sophie A1 - Vogel, Heiko A1 - Schwander, Tanja A1 - Simon, Jean-Christophe A1 - Figueroa, Christian C. A1 - Vorburger, Christoph A1 - Legeai, Fabrice A1 - Gadau, Jürgen T1 - Functional insights from the GC-poor genomes of two aphid parasitoids, Aphidius ervi and Lysiphlebus fabarum T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Background Parasitoid wasps have fascinating life cycles and play an important role in trophic networks, yet little is known about their genome content and function. Parasitoids that infect aphids are an important group with the potential for biological control. Their success depends on adapting to develop inside aphids and overcoming both host aphid defenses and their protective endosymbionts. Results We present the de novo genome assemblies, detailed annotation, and comparative analysis of two closely related parasitoid wasps that target pest aphids: Aphidius ervi and Lysiphlebus fabarum (Hymenoptera: Braconidae: Aphidiinae). The genomes are small (139 and 141 Mbp) and the most AT-rich reported thus far for any arthropod (GC content: 25.8 and 23.8%). This nucleotide bias is accompanied by skewed codon usage and is stronger in genes with adult-biased expression. AT-richness may be the consequence of reduced genome size, a near absence of DNA methylation, and energy efficiency. We identify missing desaturase genes, whose absence may underlie mimicry in the cuticular hydrocarbon profile of L. fabarum. We highlight key gene groups including those underlying venom composition, chemosensory perception, and sex determination, as well as potential losses in immune pathway genes. Conclusions These findings are of fundamental interest for insect evolution and biological control applications. They provide a strong foundation for further functional studies into coevolution between parasitoids and their hosts. Both genomes are available at https://bipaa.genouest.org. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 989 KW - Parasitoid wasp KW - Aphid host KW - Aphidius ervi KW - GC content KW - de novo genome assembly KW - DNA methylation loss KW - Chemosensory genes KW - Toll and Imd pathways KW - Venom proteins KW - Lysiphlebus fabarum Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-476129 SN - 1866-8372 IS - 989 ER - TY - GEN A1 - Paraskevopoulou, Sofia A1 - Dennis, Alice B. A1 - Weithoff, Guntram A1 - Hartmann, Stefanie A1 - Tiedemann, Ralph T1 - Within species expressed genetic variability and gene expression response to different temperatures in the rotifer Brachionus calyciflorus sensu stricto T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Genetic divergence is impacted by many factors, including phylogenetic history, gene flow, genetic drift, and divergent selection. Rotifers are an important component of aquatic ecosystems, and genetic variation is essential to their ongoing adaptive diversification and local adaptation. In addition to coding sequence divergence, variation in gene expression may relate to variable heat tolerance, and can impose ecological barriers within species. Temperature plays a significant role in aquatic ecosystems by affecting species abundance, spatio-temporal distribution, and habitat colonization. Recently described (formerly cryptic) species of the Brachionus calyciflorus complex exhibit different temperature tolerance both in natural and in laboratory studies, and show that B. calyciflorus sensu stricto (s.s.) is a thermotolerant species. Even within B. calyciflorus s.s., there is a tendency for further temperature specializations. Comparison of expressed genes allows us to assess the impact of stressors on both expression and sequence divergence among disparate populations within a single species. Here, we have used RNA-seq to explore expressed genetic diversity in B. calyciflorus s.s. in two mitochondrial DNA lineages with different phylogenetic histories and differences in thermotolerance. We identify a suite of candidate genes that may underlie local adaptation, with a particular focus on the response to sustained high or low temperatures. We do not find adaptive divergence in established candidate genes for thermal adaptation. Rather, we detect divergent selection among our two lineages in genes related to metabolism (lipid metabolism, metabolism of xenobiotics). T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 796 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-441050 SN - 1866-8372 IS - 796 ER -