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Elguweidi A, Crease T. Copy number and sequence variation in rDNA of Daphnia pulex from natural populations: insights from whole-genome sequencing. G3 (BETHESDA, MD.) 2024; 14:jkae105. [PMID: 38771699 PMCID: PMC11228840 DOI: 10.1093/g3journal/jkae105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 02/17/2024] [Accepted: 05/10/2024] [Indexed: 05/23/2024]
Abstract
Ribosomal DNA (rDNA) has a vital role in ribosome biogenesis as it contains the genes that encode ribosomal RNA (rRNA) separated by intergenic spacers (IGSs). The rRNA genes occur in hundreds to tens of thousands of copies per haploid genome in eukaryotes and are generally highly conserved with low variation within species. Due to the repetitive nature and large size of rDNA arrays, detecting intraindividual variation can be difficult. In this study, we use whole-genome sequences of 169 Daphnia pulex individuals from 10 natural populations to measure the copy number and sequence variation in rDNA. This revealed that variation in rDNA copy number between individuals spans an order of magnitude. We further observed a substantial level of sequence variation within individual genomes. As expected, single-nucleotide polymorphisms occurred in regions of lower functional constraint such as the IGS and expansion segments of the rRNA genes. The presence of strong linkage disequilibrium among variants facilitated identification of haplotypes within each population. Although there was evidence of recombination among haplotypes from different populations, it is insufficient to eliminate linkage disequilibrium within populations. Estimating copy number and haplotype diversity within individuals revealed that the level of intraindividual sequence variation is not strongly correlated with copy number. The observed patterns of variation highlight a complex evolutionary history of rDNA in D. pulex. Future research should explore the functional implications of rDNA copy number and sequence variation on organismal phenotypes.
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Affiliation(s)
- Abir Elguweidi
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G2W1, Canada
| | - Teresa Crease
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G2W1, Canada
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2
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Wang H, Liu K, He Z, Chen Y, Hu Z, Chen W, Leaw CP, Chen N. Extensive intragenomic variations of the 18S rDNA V4 region in the toxigenic diatom species Pseudo-nitzschia multistriata revealed through high-throughput sequencing. MARINE POLLUTION BULLETIN 2024; 201:116198. [PMID: 38428045 DOI: 10.1016/j.marpolbul.2024.116198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 02/21/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024]
Abstract
Metabarcoding analysis is an effective technique for monitoring the domoic acid-producing Pseudo-nitzschia species in marine environments, uncovering high-levels of molecular diversity. However, such efforts may result in the overinterpretation of Pseudo-nitzschia species diversity, as molecular diversity not only encompasses interspecies and intraspecies diversities but also exhibits extensive intragenomic variations (IGVs). In this study, we analyzed the V4 region of the 18S rDNA of 30 strains of Pseudo-nitzschia multistriata collected from the coasts of China. The results showed that each P. multistriata strain harbored about a hundred of unique 18S rDNA V4 sequence varieties, of which each represented by a unique amplicon sequence variant (ASV). This study demonstrated the extensive degree of IGVs in P. multistriata strains, suggesting that IGVs may also present in other Pseudo-nitzschia species and other phytoplankton species. Understanding the scope and levels of IGVs is crucial for accurately interpreting the results of metabarcoding analysis.
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Affiliation(s)
- Hui Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China; College of Marine Science, University of Chinese Academy of Sciences, Beijing 100039, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Kuiyan Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China; College of Marine Science, University of Chinese Academy of Sciences, Beijing 100039, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Ziyan He
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China; College of Marine Science, University of Chinese Academy of Sciences, Beijing 100039, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yang Chen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China; College of Marine Science, University of Chinese Academy of Sciences, Beijing 100039, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Zhangxi Hu
- Department of Aquaculture, College of Fisheries, Guangdong Ocean University, Zhanjiang, Guangdong 524088, China
| | - Weizhou Chen
- Institution of Marine Biology, Shantou University, Shantou, Guangdong 515063, China
| | - Chui Pin Leaw
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia
| | - Nansheng Chen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada.
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3
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Murik O, Geffen O, Shotland Y, Fernandez-Pozo N, Ullrich KK, Walther D, Rensing SA, Treves H. Genomic imprints of unparalleled growth. THE NEW PHYTOLOGIST 2024; 241:1144-1160. [PMID: 38072860 DOI: 10.1111/nph.19444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 10/31/2023] [Indexed: 12/23/2023]
Abstract
Chlorella ohadii was isolated from desert biological soil crusts, one of the harshest habitats on Earth, and is emerging as an exciting new green model for studying growth, photosynthesis and metabolism under a wide range of conditions. Here, we compared the genome of C. ohadii, the fastest growing alga on record, to that of other green algae, to reveal the genomic imprints empowering its unparalleled growth rate and resistance to various stressors, including extreme illumination. This included the genome of its close relative, but slower growing and photodamage sensitive, C. sorokiniana UTEX 1663. A larger number of ribosome-encoding genes, high intron abundance, increased codon bias and unique genes potentially involved in metabolic flexibility and resistance to photodamage are all consistent with the faster growth of C. ohadii. Some of these characteristics highlight general trends in Chlorophyta and Chlorella spp. evolution, and others open new broad avenues for mechanistic exploration of their relationship with growth. This work entails a unique case study for the genomic adaptations and costs of exceptionally fast growth and sheds light on the genomic signatures of fast growth in photosynthetic cells. It also provides an important resource for future studies leveraging the unique properties of C. ohadii for photosynthesis and stress response research alongside their utilization for synthetic biology and biotechnology aims.
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Affiliation(s)
- Omer Murik
- Department of Plant and Environmental Sciences, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
- Medical Genetics Institute, Shaare Zedek Medical Center, 93722, Jerusalem, Israel
| | - Or Geffen
- School of Plant Sciences and Food Security, Tel-Aviv University, 39040, Tel-Aviv, Israel
| | - Yoram Shotland
- Chemical Engineering, Shamoon College of Engineering, 84100, Beer-Sheva, Israel
| | - Noe Fernandez-Pozo
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
| | - Kristian Karsten Ullrich
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
- Max-Planck Institute for Evolutionary Biology, 24306, Plön, Germany
| | - Dirk Walther
- Max-Planck Institute for Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Stefan Andreas Rensing
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
- Center for Biological Signaling Studies (BIOSS), University of Freiburg, 79098, Freiburg, Germany
| | - Haim Treves
- School of Plant Sciences and Food Security, Tel-Aviv University, 39040, Tel-Aviv, Israel
- Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663, Kaiserslautern, Germany
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4
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Le TH, Pham LTK, Van Quyen D, Nguyen KT, Doan HTT, Saijuntha W, Blair D. The ribosomal transcription units of five echinostomes and their taxonomic implications for the suborder Echinostomata (Trematoda: Platyhelminthes). Parasitol Res 2024; 123:103. [PMID: 38236312 DOI: 10.1007/s00436-023-08110-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/28/2023] [Indexed: 01/19/2024]
Abstract
Five newly obtained nuclear ribosomal transcription unit (rTU) sequences from Echinostomatidae and Echinochasmidae are presented. The inter- and intrafamilial relationships of these and other families in the suborder Echinostomata are also analyzed. The sequences obtained are the complete rTU of Artyfechinostomum malayanum (9,499 bp), the near-complete rTU of Hypoderaeum conoideum (8,076 bp), and the coding regions (from 5'-terminus of 18S to 3'-terminus of 28S rRNA gene) in Echinostoma revolutum (6,856 bp), Echinostoma miyagawai (6,854 bp), and Echinochasmus japonicus (7,150 bp). Except for the longer first internal transcribed spacer (ITS1) in Echinochasmus japonicus, all genes and spacers were almost identical in length. Comprehensive maximum-likelihood phylogenies were constructed using the PhyML software package. The datasets were either the concatenated 28S + 18S rDNA sequences (5.7-5.8 kb) from 60 complete rTUs of 19 families or complete 28S sequences only (about 3.8-3.9 kb) from 70 strains or species of 22 families. The phylogenetic trees confirmed Echinostomatoidea as monophyletic. Furthermore, a detailed phylogeny constructed from alignments of 169 28S D1-D3 rDNA sequences (1.1-1.3 kb) from 98 species of 50 genera of 10 families, including 154 echinostomatoid sequences (85 species/42 genera), clearly indicated known generic relationships within Echinostomatidae and Echinochasmidae and relationships of families within Echinostomata and several other suborders. Within Echinostomatidae, Echinostoma, Artyfechinostomum, and Hypoderaeum appeared as monophyletic, while Echinochasmus (Echinochasmidae) was polyphyletic. The Echinochasmidae are a sister group to the Psilostomidae. The datasets provided here will be useful for taxonomic reappraisal as well as studies of evolutionary and population genetics in the superfamily Echinostomatoidea, the sole superfamily in the suborder Echinostomata.
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Affiliation(s)
- Thanh Hoa Le
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam.
| | - Linh Thi Khanh Pham
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
- University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Dong Van Quyen
- University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
- Molecular Microbiology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Khue Thi Nguyen
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Huong Thi Thanh Doan
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | | | - David Blair
- College of Science and Engineering, James Cook University, Townsville, Queensland, 4811, Australia
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5
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Le TH, Nguyen KT, Pham LTK, Doan HTT, Roan DT, Le XTK, Agatsuma T, Blair D. Mitogenomic and nuclear ribosomal transcription unit datasets support the synonymy of Paragonimus iloktsuenensis and P. ohirai (Paragonimidae: Platyhelminthes). Parasitol Res 2023:10.1007/s00436-023-07854-y. [PMID: 37101088 DOI: 10.1007/s00436-023-07854-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 04/18/2023] [Indexed: 04/28/2023]
Abstract
The complete mitogenome (mtDNA) of nominal Paragonimus iloktsuenensis (Paragonimidae: Trematoda) and the nuclear ribosomal transcription unit (rTU) coding region (rTU*: from 5'-terminus of 18S to 3'-terminus of 28S rRNA gene, excluding the external spacer region) of this species and of P. ohirai were obtained and used to further support the previously suggested synonymy of these taxa in the P. ohirai complex. The complete mitogenome of P. iloktsuenensis was 14,827 bp long (GenBank: ON961029) and nearly identical to that of P. ohirai (14,818 bp; KX765277), with a 99.12% nucleotide identity. The rTU* was 7543 bp and 6932 bp in these two taxa, respectively. All genes and spacers in the rTU were identical in length, with exception of the first internal transcribed spacer, which contained multiple tandem repeat units (6.7 for P. iloktsuenensis and 5.7 for P. ohirai). There was near 100% identity for the rTU genes. The phylogenetic topology inferred from the mtDNA and from individual gene regions (partial cox1 of 387 bp and the ITS-2 of 282 bp - 285 bp) indicated a very close relationship consistent with synonymy of P. iloktsuenensis and P. ohirai. The datasets provided here will be useful for taxonomic reappraisal as well as studies of evolutionary and population genetics of the genus Paragonimus and family Paragonimidae.
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Affiliation(s)
- Thanh Hoa Le
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam.
- Graduate University of Science and Technology (GUST), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam.
| | - Khue Thi Nguyen
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Linh Thi Khanh Pham
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Huong Thi Thanh Doan
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
- Graduate University of Science and Technology (GUST), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Do Thi Roan
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Xuyen Thi Kim Le
- Immunology Department, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Takeshi Agatsuma
- Department of Environmental Health Sciences, Kochi Medical School, Kohasu, Oko-Cho 185-1, Nankoku, Kochi, 783-8505, Japan
| | - David Blair
- College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia.
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6
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Greco M, Morard R, Darling K, Kucera M. Macroevolutionary patterns in intragenomic rDNA variability among planktonic foraminifera. PeerJ 2023; 11:e15255. [PMID: 37123000 PMCID: PMC10143585 DOI: 10.7717/peerj.15255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 03/28/2023] [Indexed: 05/02/2023] Open
Abstract
Ribosomal intragenomic variability in prokaryotes and eukaryotes is a genomic feature commonly studied for its inflationary impact on molecular diversity assessments. However, the evolutionary mechanisms and distribution of this phenomenon within a microbial group are rarely explored. Here, we investigate the intragenomic variability in 33 species of planktonic foraminifera, calcifying marine protists, by inspecting 2,403 partial SSU sequences obtained from single-cell clone libraries. Our analyses show that polymorphisms are common among planktonic foraminifera species, but the number of polymorphic sites significantly differs among clades. With our molecular simulations, we could assess that most of these mutations are located in paired regions that do not affect the secondary structure of the SSU fragment. Finally, by mapping the number of polymorphic sites on the phylogeny of the clades, we were able to discuss the evolution and potential sources of intragenomic variability in planktonic foraminifera, linking this trait to the distinctive nuclear and genomic dynamics of this microbial group.
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Affiliation(s)
- Mattia Greco
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
- MARUM-Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- Institut de Ciències del Mar (ICM), Consejo Superior de Investigaciones Científicas, Barcelona, Spain
| | - Raphaël Morard
- MARUM-Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Kate Darling
- School of Geosciences, University of Edinburgh, Edinburgh, United Kingdom
- Biological and Environmental Sciences, University of Stirling, Stirling, United Kingdom
| | - Michal Kucera
- MARUM-Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
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7
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Isanta‐Navarro J, Prater C, Peoples LM, Loladze I, Phan T, Jeyasingh PD, Church MJ, Kuang Y, Elser JJ. Revisiting the growth rate hypothesis: Towards a holistic stoichiometric understanding of growth. Ecol Lett 2022; 25:2324-2339. [PMID: 36089849 PMCID: PMC9595043 DOI: 10.1111/ele.14096] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/27/2022] [Accepted: 07/31/2022] [Indexed: 01/11/2023]
Abstract
The growth rate hypothesis (GRH) posits that variation in organismal stoichiometry (C:P and N:P ratios) is driven by growth-dependent allocation of P to ribosomal RNA. The GRH has found broad but not uniform support in studies across diverse biota and habitats. We synthesise information on how and why the tripartite growth-RNA-P relationship predicted by the GRH may be uncoupled and outline paths for both theoretical and empirical work needed to broaden the working domain of the GRH. We found strong support for growth to RNA (r2 = 0.59) and RNA-P to P (r2 = 0.63) relationships across taxa, but growth to P relationships were relatively weaker (r2 = 0.09). Together, the GRH was supported in ~50% of studies. Mechanisms behind GRH uncoupling were diverse but could generally be attributed to physiological (P accumulation in non-RNA pools, inactive ribosomes, translation elongation rates and protein turnover rates), ecological (limitation by resources other than P), and evolutionary (adaptation to different nutrient supply regimes) causes. These factors should be accounted for in empirical tests of the GRH and formalised mathematically to facilitate a predictive understanding of growth.
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Affiliation(s)
- Jana Isanta‐Navarro
- Flathead Lake Biological StationUniversity of MontanaPolsonMontanaUSA,Department of BiologyLund UniversityLundSweden
| | - Clay Prater
- Department of Integrative BiologyUniversity of OklahomaStillwaterOklahomaUSA
| | - Logan M. Peoples
- Flathead Lake Biological StationUniversity of MontanaPolsonMontanaUSA
| | - Irakli Loladze
- Bryan College of Health Sciences, Lincoln, NE, USA and School of Mathematical & Statistical SciencesArizona State UniversityTempeArizonaUSA
| | - Tin Phan
- Division of Theoretical Biology and BiophysicsLos Alamos National LaboratoryLos AlamosNew MexicoUSA
| | | | - Matthew J. Church
- Flathead Lake Biological StationUniversity of MontanaPolsonMontanaUSA
| | - Yang Kuang
- School of Life SciencesArizona State UniversityTempeArizonaUSA
| | - James J. Elser
- Flathead Lake Biological StationUniversity of MontanaPolsonMontanaUSA
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8
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Karaoz U, Brodie EL. microTrait: A Toolset for a Trait-Based Representation of Microbial Genomes. FRONTIERS IN BIOINFORMATICS 2022; 2:918853. [PMID: 36304272 PMCID: PMC9580909 DOI: 10.3389/fbinf.2022.918853] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/20/2022] [Indexed: 11/29/2023] Open
Abstract
Remote sensing approaches have revolutionized the study of macroorganisms, allowing theories of population and community ecology to be tested across increasingly larger scales without much compromise in resolution of biological complexity. In microbial ecology, our remote window into the ecology of microorganisms is through the lens of genome sequencing. For microbial organisms, recent evidence from genomes recovered from metagenomic samples corroborate a highly complex view of their metabolic diversity and other associated traits which map into high physiological complexity. Regardless, during the first decades of this omics era, microbial ecological research has primarily focused on taxa and functional genes as ecological units, favoring breadth of coverage over resolution of biological complexity manifested as physiological diversity. Recently, the rate at which provisional draft genomes are generated has increased substantially, giving new insights into ecological processes and interactions. From a genotype perspective, the wide availability of genome-centric data requires new data synthesis approaches that place organismal genomes center stage in the study of environmental roles and functional performance. Extraction of ecologically relevant traits from microbial genomes will be essential to the future of microbial ecological research. Here, we present microTrait, a computational pipeline that infers and distills ecologically relevant traits from microbial genome sequences. microTrait maps a genome sequence into a trait space, including discrete and continuous traits, as well as simple and composite. Traits are inferred from genes and pathways representing energetic, resource acquisition, and stress tolerance mechanisms, while genome-wide signatures are used to infer composite, or life history, traits of microorganisms. This approach is extensible to any microbial habitat, although we provide initial examples of this approach with reference to soil microbiomes.
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Affiliation(s)
- Ulas Karaoz
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Eoin L. Brodie
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States
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9
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Gluck-Thaler E, Ralston T, Konkel Z, Ocampos CG, Ganeshan VD, Dorrance AE, Niblack TL, Wood CW, Slot JC, Lopez-Nicora HD, Vogan AA. Giant Starship Elements Mobilize Accessory Genes in Fungal Genomes. Mol Biol Evol 2022; 39:msac109. [PMID: 35588244 PMCID: PMC9156397 DOI: 10.1093/molbev/msac109] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Accessory genes are variably present among members of a species and are a reservoir of adaptive functions. In bacteria, differences in gene distributions among individuals largely result from mobile elements that acquire and disperse accessory genes as cargo. In contrast, the impact of cargo-carrying elements on eukaryotic evolution remains largely unknown. Here, we show that variation in genome content within multiple fungal species is facilitated by Starships, a newly discovered group of massive mobile elements that are 110 kb long on average, share conserved components, and carry diverse arrays of accessory genes. We identified hundreds of Starship-like regions across every major class of filamentous Ascomycetes, including 28 distinct Starships that range from 27 to 393 kb and last shared a common ancestor ca. 400 Ma. Using new long-read assemblies of the plant pathogen Macrophomina phaseolina, we characterize four additional Starships whose activities contribute to standing variation in genome structure and content. One of these elements, Voyager, inserts into 5S rDNA and contains a candidate virulence factor whose increasing copy number has contrasting associations with pathogenic and saprophytic growth, suggesting Voyager's activity underlies an ecological trade-off. We propose that Starships are eukaryotic analogs of bacterial integrative and conjugative elements based on parallels between their conserved components and may therefore represent the first dedicated agents of active gene transfer in eukaryotes. Our results suggest that Starships have shaped the content and structure of fungal genomes for millions of years and reveal a new concerted route for evolution throughout an entire eukaryotic phylum.
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Affiliation(s)
- Emile Gluck-Thaler
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Plant Pathology, The Ohio State University, Columbus, OH, USA
| | - Timothy Ralston
- Department of Plant Pathology, The Ohio State University, Columbus, OH, USA
| | - Zachary Konkel
- Department of Plant Pathology, The Ohio State University, Columbus, OH, USA
| | | | - Veena Devi Ganeshan
- Arabidopsis Biological Resource Center, The Ohio State University, Columbus, OH, USA
| | - Anne E. Dorrance
- Department of Plant Pathology, The Ohio State University, Wooster, OH, USA
| | - Terry L. Niblack
- Department of Plant Pathology, The Ohio State University, Columbus, OH, USA
| | - Corlett W. Wood
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jason C. Slot
- Department of Plant Pathology, The Ohio State University, Columbus, OH, USA
| | - Horacio D. Lopez-Nicora
- Department of Plant Pathology, The Ohio State University, Columbus, OH, USA
- Departamento de Producción Agrícola, Universidad San Carlos, Asunción, Paraguay
| | - Aaron A. Vogan
- Systematic Biology, Department of Organismal Biology, University of Uppsala, Uppsala, Sweden
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10
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Hall AN, Morton E, Queitsch C. First discovered, long out of sight, finally visible: ribosomal DNA. Trends Genet 2022; 38:587-597. [PMID: 35272860 PMCID: PMC10132741 DOI: 10.1016/j.tig.2022.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 10/18/2022]
Abstract
With the advent of long-read sequencing, previously unresolvable genomic elements are being revisited in an effort to generate fully complete reference genomes. One such element is ribosomal DNA (rDNA), the highly conserved genomic region that encodes rRNAs. Genomic structure and content of the rDNA are variable in both prokarya and eukarya, posing interesting questions about the biology of rDNA. Here, we consider the types of variation observed in rDNA - including locus structure and number, copy number, and sequence variation - and their known phenotypic consequences. With recent advances in long-read sequencing technology, incorporating the full rDNA sequence into reference genomes is within reach. This knowledge will have important implications for understanding rDNA biology within the context of cell physiology and whole-organism phenotypes.
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11
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Zou S, Fu R, Deng H, Zhang Q, Gentekaki E, Gong J. Coupling between Ribotypic and Phenotypic Traits of Protists across Life Cycle Stages and Temperatures. Microbiol Spectr 2021; 9:e0173821. [PMID: 34817220 PMCID: PMC8612162 DOI: 10.1128/spectrum.01738-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 10/16/2021] [Indexed: 01/04/2023] Open
Abstract
Relationships between ribotypic and phenotypic traits of protists across life cycle stages remain largely unknown. Herein, we used single cells of two soil and two marine ciliate species to examine phenotypic and ribotypic traits and their relationships across lag, log, plateau, cystic stages and temperatures. We found that Colpoda inflata and Colpoda steinii demonstrated allometric relationships between 18S ribosomal DNA (rDNA) copy number per cell (CNPC), cell volume (CV), and macronuclear volume across all life cycle stages. Integrating previously reported data of Euplotes vannus and Strombidium sulcatum indicated taxon-dependent rDNA CNPC-CV functions. Ciliate and prokaryote data analysis revealed that the rRNA CNPC followed a unified power-law function only if the rRNA-deficient resting cysts were not considered. Hence, a theoretical framework was proposed to estimate the relative quantity of resting cysts in the protistan populations with total cellular rDNA and rRNA copy numbers. Using rDNA CNPC was a better predictor of growth rate at a given temperature than rRNA CNPC and CV, suggesting replication of redundant rDNA operons as a key factor that slows cell division. Single-cell high-throughput sequencing and analysis after correcting sequencing errors revealed multiple rDNA and rRNA variants per cell. Both encystment and temperature affected the number of rDNA and rRNA variants in several cases. The divergence of rDNA and rRNA sequence in a single cell ranged from 1% to 10% depending on species. These findings have important implications for inferring cell-based biological traits (e.g., species richness, abundance and biomass, activity, and community structure) of protists using molecular approaches. IMPORTANCE Based on phenotypic traits, traditional surveys usually characterize organismal richness, abundance, biomass, and growth potential to describe diversity, organization, and function of protistan populations and communities. The rRNA gene (rDNA) and its transcripts have been widely used as molecular markers in ecological studies of protists. Nevertheless, the manner in which these molecules relate to cellular (organismal) and physiological traits remains poorly understood, which could lead to misinterpretations of protistan diversity and ecology. The current research highlights the dynamic nature of cellular rDNA and rRNA contents, which tightly couple with multiple phenotypic traits in ciliated protists. We demonstrate that quantity of resting cysts and maximum growth rate of a population can be theoretically estimated using ribotypic trait-based models. The intraindividual sequence polymorphisms of rDNA and rRNA can be influenced by encystment and temperature, which should be considered when interpreting species-level diversity and community structure of microbial eukaryotes.
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Affiliation(s)
- Songbao Zou
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Healthy Freshwater Aquaculture, Ministry of Agriculture and Rural Affairs, Huzhou, China
- Key Laboratory of Fish Health and Nutrition of Zhejiang Province, Zhejiang Institute of Freshwater Fisheries, Huzhou, China
| | - Rao Fu
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- University of Chinese Academy of Sciences, Beijing, China
- Shandong Institute of Sericulture, Shandong Academy of Agricultural Sciences, Yantai, China
| | - Huiwen Deng
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, China
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, China
| | - Qianqian Zhang
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Eleni Gentekaki
- School of Science, Mae Fah Luang University, Chiang Rai, Thailand
| | - Jun Gong
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, China
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, China
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12
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DNA Multi-Marker Genotyping and CIAS Morphometric Phenotyping of Fasciola gigantica-Sized Flukes from Ecuador, with an Analysis of the Radix Absence in the New World and the Evolutionary Lymnaeid Snail Vector Filter. Animals (Basel) 2021; 11:ani11092495. [PMID: 34573461 PMCID: PMC8472080 DOI: 10.3390/ani11092495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/13/2021] [Accepted: 08/22/2021] [Indexed: 01/04/2023] Open
Abstract
Simple Summary Fasciolid flukes collected from sheep and cattle in Ecuador showed a high diversity in DNA sequences whose analyses indicated introductions from South America, European and North American countries. These results agree with the numerous livestock importations performed by Ecuador. Abnormally big-sized liver flukes were found in Ecuadorian sheep. The morphometric phenotypic CIAS study showed that its size maximum and mean very pronouncedly and significantly surpassed those of the Fasciola hepatica populations from South America and Spain and proved to be intermediate between standard F. hepatica and F. gigantica populations. Such a feature is only known in intermediate fasciolid forms in Old World areas where the two species and their specific lymnaeid snail vectors overlap. This argues about a past hybridization after F. gigantica importation from Pakistan and/or introduction of intermediate hybrids previously generated in USA. The lack of heterozygotic rDNA ITS positions differentiating the two species, and of introgressed fragments and heteroplasmic positions in mtDNA genes, indicate a post-hybridization period sufficiently long as for rDNA concerted evolution to complete homogenization and mtDNA to return to homoplasmy. The vector specificity filter due to Radix absence should act as a driving force in accelerating such lineage evolution. Public health implications are finally emphasized. Abstract Fascioliasis is a disease caused by Fasciola hepatica worldwide transmitted by lymnaeid snails mainly of the Galba/Fossaria group and F. gigantica restricted to parts of Africa and Asia and transmitted by Radix lymnaeids. Concern has recently risen regarding the high pathogenicity and human infection capacity of F. gigantica. Abnormally big-sized fasciolids were found infecting sheep in Ecuador, the only South American country where F. gigantica has been reported. Their phenotypic comparison with F. hepatica infecting sheep from Peru, Bolivia and Spain, and F. gigantica from Egypt and Vietnam demonstrated the Ecuadorian fasciolids to have size-linked parameters of F. gigantica. Genotyping of these big-sized fasciolids by rDNA ITS-2 and ITS-1 and mtDNA cox1 and nad1 and their comparison with other countries proved the big-sized fasciolids to belong to F. hepatica. Neither heterozygotic ITS position differentiated the two species, and no introgressed fragments and heteroplasmic positions in mtDNA were found. The haplotype diversity indicates introductions mainly from other South American countries, Europe and North America. Big-sized fasciolids from Ecuador and USA are considered to be consequences of F.gigantica introductions by past livestock importations. The vector specificity filter due to Radix absence should act as driving force in the evolution in such lineages.
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McElroy KE, Müller S, Lamatsch DK, Bankers L, Fields PD, Jalinsky JR, Sharbrough J, Boore JL, Logsdon JM, Neiman M. Asexuality Associated with Marked Genomic Expansion of Tandemly Repeated rRNA and Histone Genes. Mol Biol Evol 2021; 38:3581-3592. [PMID: 33885820 PMCID: PMC8382920 DOI: 10.1093/molbev/msab121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
How does asexual reproduction influence genome evolution? Although is it clear that genomic structural variation is common and important in natural populations, we know very little about how one of the most fundamental of eukaryotic traits-mode of genomic inheritance-influences genome structure. We address this question with the New Zealand freshwater snail Potamopyrgus antipodarum, which features multiple separately derived obligately asexual lineages that coexist and compete with otherwise similar sexual lineages. We used whole-genome sequencing reads from a diverse set of sexual and asexual individuals to analyze genomic abundance of a critically important gene family, rDNA (the genes encoding rRNAs), that is notable for dynamic and variable copy number. Our genomic survey of rDNA in P. antipodarum revealed two striking results. First, the core histone and 5S rRNA genes occur between tandem copies of the 18S-5.8S-28S gene cluster, a unique architecture for these crucial gene families. Second, asexual P. antipodarum harbor dramatically more rDNA-histone copies than sexuals, which we validated through molecular and cytogenetic analysis. The repeated expansion of this genomic region in asexual P. antipodarum lineages following distinct transitions to asexuality represents a dramatic genome structural change associated with asexual reproduction-with potential functional consequences related to the loss of sexual reproduction.
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Affiliation(s)
- Kyle E McElroy
- Ecology, Evolutionary, and Organismal Biology, Iowa State University, Ames, IA, USA
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | - Stefan Müller
- Institute of Human Genetics, Munich University Hospital, Ludwig-Maximilians University, Munich, Germany
| | - Dunja K Lamatsch
- Research Department for Limnology, University of Innsbruck, Mondsee, Mondsee, Austria
| | - Laura Bankers
- Division of Infectious Diseases, University of Colorado—Anschutz Medical Campus, Aurora, CO, USA
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | | | - Joel Sharbrough
- Biology Department, New Mexico Institute of Mining and Technology, Socorro, NM, USA
- Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Jeffrey L Boore
- Providence St. Joseph Health and Institute for Systems Biology, Seattle, WA, USA
| | - John M Logsdon
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | - Maurine Neiman
- Department of Biology, University of Iowa, Iowa City, IA, USA
- Department of Gender, Women's, and Sexuality Studies, University of Iowa, Iowa City, IA, USA
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14
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Jernfors T, Danforth J, Kesäniemi J, Lavrinienko A, Tukalenko E, Fajkus J, Dvořáčková M, Mappes T, Watts PC. Expansion of rDNA and pericentromere satellite repeats in the genomes of bank voles Myodes glareolus exposed to environmental radionuclides. Ecol Evol 2021; 11:8754-8767. [PMID: 34257925 PMCID: PMC8258220 DOI: 10.1002/ece3.7684] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/27/2021] [Accepted: 05/05/2021] [Indexed: 12/21/2022] Open
Abstract
Altered copy number of certain highly repetitive regions of the genome, such as satellite DNA within heterochromatin and ribosomal RNA loci (rDNA), is hypothesized to help safeguard the genome against damage derived from external stressors. We quantified copy number of the 18S rDNA and a pericentromeric satellite DNA (Msat-160) in bank voles (Myodes glareolus) inhabiting the Chernobyl Exclusion Zone (CEZ), an area that is contaminated by radionuclides and where organisms are exposed to elevated levels of ionizing radiation. We found a significant increase in 18S rDNA and Msat-160 content in the genomes of bank voles from contaminated locations within the CEZ compared with animals from uncontaminated locations. Moreover, 18S rDNA and Msat-160 copy number were positively correlated in the genomes of bank voles from uncontaminated, but not in the genomes of animals inhabiting contaminated, areas. These results show the capacity for local-scale geographic variation in genome architecture and are consistent with the genomic safeguard hypothesis. Disruption of cellular processes related to genomic stability appears to be a hallmark effect in bank voles inhabiting areas contaminated by radionuclides.
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Affiliation(s)
- Toni Jernfors
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - John Danforth
- Department of Biochemistry & Molecular BiologyRobson DNA Science CentreArnie Charbonneau Cancer InstituteCumming School of MedicineUniversity of CalgaryCalgaryCanada
| | - Jenni Kesäniemi
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Anton Lavrinienko
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Eugene Tukalenko
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
- National Research Center for Radiation Medicine of the National Academy of Medical ScienceKyivUkraine
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and ProteomicsCentral European Institute of Technology (CEITEC)Masaryk UniversityBrnoCzech Republic
- Laboratory of Functional Genomics and ProteomicsNCBRFaculty of ScienceMasaryk UniversityBrnoCzech Republic
- Department of Cell Biology and RadiobiologyInstitute of Biophysics of the Czech Academy of SciencesBrnoCzech Republic
| | - Martina Dvořáčková
- Mendel Centre for Plant Genomics and ProteomicsCentral European Institute of Technology (CEITEC)Masaryk UniversityBrnoCzech Republic
| | - Tapio Mappes
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Phillip C. Watts
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
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15
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Fu Z, Piumsomboon A, Punnarak P, Uttayarnmanee P, Leaw CP, Lim PT, Wang A, Gu H. Diversity and distribution of harmful microalgae in the Gulf of Thailand assessed by DNA metabarcoding. HARMFUL ALGAE 2021; 106:102063. [PMID: 34154784 DOI: 10.1016/j.hal.2021.102063] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
Information on the diversity and distribution of harmful microalgae in the Gulf of Thailand is very limited and mainly based on microscopic observations. Here, we collected 44 water samples from the Gulf of Thailand and its adjacent water (Perhentian Island, Malaysia) for comparison in 2018. DNA metabarcoding was performed targeting the partial large subunit ribosomal RNA gene (LSU rDNA D1-D3) and the internal transcribed spacers (ITS1 and ITS2). A total of 50 dinoflagellate genera (made up of 72 species) were identified based on the LSU rDNA dataset, while the results of ITS1 and ITS2 datasets revealed 33 and 32 dinoflagellate genera comprising 69 and 64 species, respectively. Five potentially toxic Pseudo-nitzschia (Bacillariophyceae) species were detected, with four as newly recorded species in the water (Pseudo-nitzschia americana/brasilliana, Pseudo-nitzschia simulans/delicatissima, P. galaxiae and P. multistriata). The highest relative abundances of P. galaxiae and P. multistriata were found in Trat Bay and Chumphon (accounting for 0.20% and 0.06% of total ASVs abundance, respectively). Three paralytic shellfish toxin producing dinoflagellate species were detected: Alexandrium tamiyavanichii, Alexandrium fragae, and Gymnodinium catenatum. The highest abundance of A. tamiyavanichii was found in the surface sample of Chumphon (CHO7 station), accounting for 1.95% of total ASVs abundance. Two azaspiracid producing dinoflagellate species, Azadinium poporum ribotype B, Azadinium spinosum ribotype A, and a pinnatoxin producing dinoflagellate species Vulcanodinium rugosum, with two ribotypes B and C, were revealed from the datasets although with very low abundances. Six fish killing dinoflagellate species, including Margalefidinium polykrikoides group IV, Margalefidinium fulvescens, Karenia mikimotoi, Karenia selliformis ribotype B, Karlodinium australe, and Karlodinium digitatum were detected and all representing new records in this area. The findings of numerous harmful microalgal species in the Gulf of Thailand highlight the potential risk of human intoxication and fish killing events.
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Affiliation(s)
- Zhengxu Fu
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | | | - Porntep Punnarak
- Aquatic Resources Research Institute, Chulalongkorn University, Bangkok 10330, Thailand
| | - Praderm Uttayarnmanee
- Marine and Coastal Resources Research and Development Center, Central Gulf of Thailand, Department of Marine and Coastal Resources, Chumphon 86000, Thailand
| | - Chui Pin Leaw
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia
| | - Po Teen Lim
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia
| | - Aijun Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
| | - Haifeng Gu
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China.
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16
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Nuotclà JA, Diehl JMC, Taborsky M. Habitat Quality Determines Dispersal Decisions and Fitness in a Beetle – Fungus Mutualism. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.602672] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Delayed dispersal of sexually mature offspring is a fundamental component of cooperative breeding. In ambrosia beetles, female offspring temporarily remain in their natal nest and refrain from reproduction, instead investing in alloparental care. Previous work has demonstrated a link between helping behaviour and the increased need for pathogen defence, arising from their close association with fungal cultivars. In the ambrosia beetle Xyleborinus saxesenii, mature female offspring can effectively fight pathogen infections and manage the microbial composition within the nest by adjusting the frequency of different hygienic and nest maintenance behaviours. This suggests a potential to respond flexibly to the ecology of their nest, which calls for a better understanding of the connection between behaviour and the microbial community thriving within their nests. Here, we studied the significance of the mutualistic fungus garden composition for the beetles’ nest ecology and fitness by experimentally varying substrate quality. We found that the vertically transmitted ambrosia fungus garden is composed of at least two fungus mutualist species and a wide variety of other microbes varying in their relative abundance. This is strongly affected by the moisture content of the substrate, which in nature depends on the age and type of wood. We found that the mutualist fungi complement each other in terms of dryness-resistance, allowing the beetles to utilise a broad range of substrates over prolonged time during which the wood gradually desiccates. Under suboptimal humidity conditions, the interaction between host and multiple fungus species has important ramifications for the behaviour of philopatric helpers, including their alloparental investment, sibling cannibalism and the timing of dispersal. Rearing five generations of beetles consecutively in dry substrate resulted in transgenerational effects on philopatry and alloparental care, probably mediated through the dominance of a particular fungus species that was driven by the experimental habitat condition. Interestingly, the nests of these selection lines produced much more offspring after five generations than any first-generation nest, which may have reflected increased egg laying by non-dispersing daughters. Our study highlights the importance of considering the interactions between the microbial community and their insect hosts for understanding social evolution in cooperatively breeding beetles.
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17
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Ribeiro T, Nascimento J, Santos A, Félix LP, Guerra M. Origin and evolution of highly polymorphic rDNA sites in Alstroemeria longistaminea (Alstroemeriaceae) and related species. Genome 2021; 64:833-845. [PMID: 33852822 DOI: 10.1139/gen-2020-0159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Alstroemeria (Alstroemeriaceae) displays a conserved and highly asymmetric karyotype, where most rDNA sites can be properly recognized by the size and morphology of the chromosomes. We analyzed the intraspecific variation of rDNA sites in A. longistaminea and compared with their distribution in other species (A. caryophyllaea and A. piauhyensis) and a representative of a sister genus, Bomarea edulis. All three species of Alstroemeria presented 2n = 16, and one to six B chromosomes were found in some individuals of A. longistaminea. There was a set of 12 conserved rDNA sites (four 5S and eight 35S) and up to 11 variable sites. B chromosomes were almost entirely covered by 35S signals, coupled with tiny 5S sites. Noteworthy, most rDNA sites found in A. caryophyllaea and A. piauhyensis were localized in chromosome positions similar to those in A. longistaminea, suggesting the existence of conserved hotspots for rDNA accumulation. Some of these hotspots were absent in Chilean Alstromeria as well in B. edulis. We propose that insertions of rDNA sequences on chromosomes do not occur randomly but rather on preferential sites or hotspots for insertions. The maintenance of these arrays, however, may be favored/constrained by different factors, resulting in stable or polymorphic sites.
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Affiliation(s)
- Tiago Ribeiro
- Laboratório de Citogenética e Evolução Vegetal, Universidade Federal de Pernambuco, Departamento de Botânica, Recife, Pernambuco, Brasil
| | - Jéssica Nascimento
- Laboratório de Citogenética e Evolução Vegetal, Universidade Federal de Pernambuco, Departamento de Botânica, Recife, Pernambuco, Brasil
| | - Amanda Santos
- Laboratório de Citogenética e Evolução Vegetal, Universidade Federal de Pernambuco, Departamento de Botânica, Recife, Pernambuco, Brasil
| | - Leonardo P Félix
- Universidade Federal da Paraíba, Departamento de Biociências, Campus II, Areia, Paraíba, Brasil
| | - Marcelo Guerra
- Laboratório de Citogenética e Evolução Vegetal, Universidade Federal de Pernambuco, Departamento de Botânica, Recife, Pernambuco, Brasil
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18
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Yarimizu K, Sildever S, Hamamoto Y, Tazawa S, Oikawa H, Yamaguchi H, Basti L, Mardones JI, Paredes-Mella J, Nagai S. Development of an absolute quantification method for ribosomal RNA gene copy numbers per eukaryotic single cell by digital PCR. HARMFUL ALGAE 2021; 103:102008. [PMID: 33980448 DOI: 10.1016/j.hal.2021.102008] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
Recent increase of Harmful Algal Blooms (HAB) causes world-wide ecological, economical, and health issues, and more attention is paid to frequent coastal monitoring for the early detection of HAB species to prevent or reduce such impacts. Use of molecular tools in addition to traditional microscopy-based observation has become one of the promising methodologies for coastal monitoring. However, as ribosomal RNA (rRNA) genes are commonly targeted in molecular studies, variability in the rRNA gene copy number within and between species must be considered to provide quantitative information in quantitative PCR (qPCR), digital PCR (dPCR), and metabarcoding analyses. Currently, this information is only available for a limited number of species. The present study utilized a dPCR technology to quantify copy numbers of rRNA genes per single cell in 16 phytoplankton species, the majority of which are toxin-producers, using a newly developed universal primer set accompanied by a labeled probe with a fluorophore and a double-quencher. In silico PCR using the newly developed primers allowed the detection of taxa from 8 supergroups, demonstrating universality and broad coverage of the primer set. Chelex buffer was found to be suitable for DNA extraction to obtain DNA fragments with suitable size to avoid underestimation of the copy numbers. The study successfully demonstrated the first comparison of absolute quantification of 18S rRNA copy numbers per cell from 16 phytoplankton species by the dPCR technology.
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Affiliation(s)
- Kyoko Yarimizu
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan; Office of Industry-Academia-Government and Community Collaboration, Hiroshima University, 1-3-2 22 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-8511, Japan
| | - Sirje Sildever
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan; Department of Marine Systems, Tallinn University of Technology, Akadeemia tee 15A, 12618 Tallinn, Estonia
| | - Yoko Hamamoto
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - Satoshi Tazawa
- AXIOHELIX Co. Ltd, 12-17 Kandaizumicho, Chiyoda-ku, Tokyo 101-0024, Japan
| | - Hiroshi Oikawa
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - Haruo Yamaguchi
- Faculty of Agriculture and Marine Sciences, Kochi University, Nankoku, Kochi 783-8502, Japan
| | - Leila Basti
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan
| | - Jorge I Mardones
- Instituto de Fomento Pesquero, Centro de Estudios de Algas Nocivas (IFOP-CREAN), Padre Harter 574, Puerto Montt 5501679, Chile; Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
| | - Javier Paredes-Mella
- Instituto de Fomento Pesquero, Centro de Estudios de Algas Nocivas (IFOP-CREAN), Padre Harter 574, Puerto Montt 5501679, Chile
| | - Satoshi Nagai
- Japan Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan.
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Gifford I, Dasgupta A, Barrick JE. Rates of gene conversions between Escherichia coli ribosomal operons. G3-GENES GENOMES GENETICS 2021; 11:5974039. [PMID: 33585862 PMCID: PMC8022953 DOI: 10.1093/g3journal/jkaa002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/10/2020] [Indexed: 11/23/2022]
Abstract
Due to their universal presence and high sequence conservation, ribosomal RNA (rRNA) sequences are used widely in phylogenetics for inferring evolutionary relationships between microbes and in metagenomics for analyzing the composition of microbial communities. Most microbial genomes encode multiple copies of rRNA genes to supply cells with sufficient capacity for protein synthesis. These copies typically undergo concerted evolution that keeps their sequences identical, or nearly so, due to gene conversion, a type of intragenomic recombination that changes one copy of a homologous sequence to exactly match another. Widely varying rates of rRNA gene conversion have previously been estimated by comparative genomics methods and using genetic reporter assays. To more directly measure rates of rRNA intragenomic recombination, we sequenced the seven Escherichia coli rRNA operons in 15 lineages that were evolved for ∼13,750 generations with frequent single-cell bottlenecks that reduce the effects of selection. We identified 38 gene conversion events and estimated an overall rate of intragenomic recombination within the 16S and 23S genes between rRNA copies of 3.6 × 10−4 per genome per generation or 8.6 × 10−6 per rRNA operon per homologous donor operon per generation. This rate varied only slightly from random expectations at different sites within the rRNA genes and between rRNA operons located at different positions in the genome. Our accurate estimate of the rate of rRNA gene conversions fills a gap in our quantitative understanding of how ribosomal sequences and other multicopy elements diversify and homogenize during microbial genome evolution.
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Affiliation(s)
- Isaac Gifford
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Aurko Dasgupta
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey E Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
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Conti A, Corte L, Casagrande Pierantoni D, Robert V, Cardinali G. What Is the Best Lens? Comparing the Resolution Power of Genome-Derived Markers and Standard Barcodes. Microorganisms 2021; 9:microorganisms9020299. [PMID: 33540579 PMCID: PMC7912933 DOI: 10.3390/microorganisms9020299] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/22/2021] [Accepted: 01/29/2021] [Indexed: 02/07/2023] Open
Abstract
Fungal species delimitation was traditionally carried out with multicopy ribosomal RNA (rRNA) genes, principally for their ease of amplification. Since the efficacy of these markers has been questioned, single-copy protein-encoding genes have been proposed alone or in combination for Multi-Locus Sequence Typing (MLST). In this context, the role of the many sequences obtained with Next-Generation Sequencing (NGS) techniques, in both genomics and metagenomics, further pushes toward an analysis of the efficacy of NGS-derived markers and of the metrics to evaluate the marker efficacy in discriminating fungal species. This paper aims at proposing MeTRe (Mean Taxonomic Resolution), a novel index that could be used both for measuring marker efficacy and for assessing the actual resolution (i.e., the level of separation) between species obtained with different markers or their combinations. In this paper, we described and then employed this index to compare the efficacy of two rRNAs and four single-copy markers obtained from public databases as both an amplicon-based approach and genome-derived sequences. Two different groups of species were used, one with a pathogenic species of Candida that was characterized by relatively well-separated taxa, whereas the other, comprising some relevant species of the sensu stricto group of the genus Saccharomyces, included close species and interspecific hybrids. The results showed the ability of MeTRe to evaluate marker efficacy in general and genome-derived markers specifically.
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Affiliation(s)
- Angela Conti
- Department of Pharmaceutical Sciences, University of Perugia, 06121 Perugia, Italy; (A.C.); (L.C.); (D.C.P.)
| | - Laura Corte
- Department of Pharmaceutical Sciences, University of Perugia, 06121 Perugia, Italy; (A.C.); (L.C.); (D.C.P.)
| | | | - Vincent Robert
- Westerdjik Institute for Biodiversity, 3584 Utrecht, The Netherlands;
| | - Gianluigi Cardinali
- Department of Pharmaceutical Sciences, University of Perugia, 06121 Perugia, Italy; (A.C.); (L.C.); (D.C.P.)
- CEMIN Excellence Research Centre, 06123 Perugia, Italy
- Correspondence:
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21
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Sherman RE, Hartnett R, Kiehnau EL, Weider LJ, Jeyasingh PD. Quantitative genetics of phosphorus content in the freshwater herbivore, Daphnia pulicaria. J Anim Ecol 2020; 90:909-916. [PMID: 33368234 DOI: 10.1111/1365-2656.13419] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/02/2020] [Indexed: 11/29/2022]
Abstract
Phosphorus (P) is essential for growth of all organisms, and P content is correlated with growth in most taxa. Although P content was initially considered to be a trait fixed at the species level, there is growing evidence for considerable intraspecific variation. Selection on such variation can thus alter the rates at which P fluxes through food webs. Nevertheless, prior work describing the sources and extent of intraspecific variation in P content were not genetically explicit, confounded by unknown genetic background and evolutionary history. We constructed an F2 recombinant population of the dominant freshwater grazer, Daphnia pulicaria to mitigate such issues. F2 recombinants exhibited considerable variation in growth rate, P content (0.49%-1.97%), P use efficiency (PUE; 51-208 mg biomass/mg P), and correlated traits such as hatching time of resting eggs, in common garden conditions. These results clearly demonstrate the scope of genetic recombination in generating variation in ecologically relevant traits. The absence of environmental selection is a likely component driving such variation not observed in natural settings. Although phosphoglucose isomerase (PGI) genotype was significantly associated with variation in hatching time of resting eggs, contrary to prior work with less rigorous designs, and allelic variation at the PGI locus did not explain variation in P content and PUE of Daphnia, indicating that such quantitative traits are under polygenic control. Together, these results suggest that although there is considerable genetic scope for variation in key ecologically relevant traits, such as P content and efficiency of P use, these traits are likely under strong stabilizing selection, most likely due to selection on growth rate and size. Importantly, our observations suggest that anthropogenic alterations to P supply due to eutrophication could alter selection on these traits, thereby rapidly altering the role Daphnia plays in the P cycle of lakes.
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Affiliation(s)
- Ryan E Sherman
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, USA
| | - Rachel Hartnett
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, USA.,Department of Biology, Program in Ecology & Evolutionary Biology, University of Oklahoma, Norman, OK, USA
| | - Emily L Kiehnau
- Department of Biology, Program in Ecology & Evolutionary Biology, University of Oklahoma, Norman, OK, USA
| | - Lawrence J Weider
- Department of Biology, Program in Ecology & Evolutionary Biology, University of Oklahoma, Norman, OK, USA
| | - Punidan D Jeyasingh
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, USA
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22
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Harvey EF, Cristescu ME, Dale J, Hunter H, Randall C, Crease TJ. Metal exposure causes rDNA copy number to fluctuate in mutation accumulation lines of Daphnia pulex. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 226:105556. [PMID: 32652413 DOI: 10.1016/j.aquatox.2020.105556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 05/29/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
Ribosomal (r)DNA is a highly dynamic, conserved, multigene family whose sequence homogeneity is thought to be maintained by intra- and interchromosomal recombination, which are capable of changing rDNA copy number. It is generally not known how environmental stress such as sublethal exposure to environmentally relevant concentrations of metals impacts rDNA copy number. To determine how chronic metal exposure affects rDNA, we measured copy number of the 18S rRNA gene in 355 copper and nickel-exposed samples and 132 metal-free samples derived from 325 mutation accumulation (MA) lines of two genetically distinct Daphnia pulex lineages. The MA lines were sampled at four time points over 100+ generations of clonal propagation. The copy number of rDNA was also measured in 15 individuals sampled from a metal-free non-MA control population established from the same progenitor as one of the MA lineages. We found that mean rDNA copy number fluctuated across lines exposed to metals with a tendency to decrease over time. In contrast, mean rDNA copy number in the metal-free control lines and the non-MA population remained stable over time. It is generally accepted that extreme rDNA loss results in the loss of organism fitness. Thus, fluctuations in rDNA copy number, including losses, could affect the long-term viability of natural populations of Daphnia in metal-contaminated habitats.
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Affiliation(s)
- Eleanor F Harvey
- Department of Integrative Biology, University of Guelph, 50 Stone Road West, Guelph, ON, N1G 2W1, Canada
| | - Melania E Cristescu
- Biology Department, McGill University, Stewart Biology Building, 1205 Dr Penfield Ave, Montreal, QC, H3A 1B1, Canada
| | - Jenna Dale
- Department of Integrative Biology, University of Guelph, 50 Stone Road West, Guelph, ON, N1G 2W1, Canada
| | - Hailey Hunter
- Department of Integrative Biology, University of Guelph, 50 Stone Road West, Guelph, ON, N1G 2W1, Canada
| | - Connor Randall
- Department of Integrative Biology, University of Guelph, 50 Stone Road West, Guelph, ON, N1G 2W1, Canada
| | - Teresa J Crease
- Department of Integrative Biology, University of Guelph, 50 Stone Road West, Guelph, ON, N1G 2W1, Canada.
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Does Intraspecific Variation in rDNA Copy Number Affect Analysis of Microbial Communities? Trends Microbiol 2020; 29:19-27. [PMID: 32593503 DOI: 10.1016/j.tim.2020.05.019] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/23/2020] [Accepted: 05/28/2020] [Indexed: 01/01/2023]
Abstract
Amplicon sequencing of partial regions of the ribosomal RNA loci (rDNA) is widely used to profile microbial communities. However, the rDNA is dynamic and can exhibit substantial interspecific and intraspecific variation in copy number in prokaryotes and, especially, in microbial eukaryotes. As change in rDNA copy number is a common response to environmental change, rDNA copy number is not necessarily a property of a species. Variation in rDNA copy number, especially the capacity for large intraspecific changes driven by external cues, complicates analyses of rDNA amplicon sequence data. We highlight the need to (i) interpret amplicon sequence data in light of possible interspecific and intraspecific variation, and (ii) examine the potential plasticity in rDNA copy number as an important ecological factor to better understand how microbial communities are structured in heterogeneous environments.
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Lin S, Hu Z, Deng Y, Shang L, Gobler CJ, Tang YZ. An assessment on the intrapopulational and intraindividual genetic diversity in LSU rDNA in the harmful algal blooms-forming dinoflagellate Margalefidinium (= Cochlodinium) fulvescens based on clonal cultures and bloom samples from Jiaozhou Bay, China. HARMFUL ALGAE 2020; 96:101821. [PMID: 32560829 DOI: 10.1016/j.hal.2020.101821] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/20/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Large subunit ribosomal DNA (LSU rDNA) sequences have been increasingly used to infer the phylogeny and species identity of organisms, a few previous studies, however, have observed high intraspecific and even intraindividual variability in LSU rDNA in some dinoflagellate species due to, assumably, large copy numbers of rDNA in dinoflagellates. Since the copy number of LSU rDNA varies tremendously among dinoflagellate species, the intraspecific and intraindividual diversity for a species of particular interest thus needs to be investigated individually. As a toxic and HABs-forming dinoflagellate, Margalefidinium (= Cochlodinium) fulvescens has been observed to approach blooming density in Jiaozhou Bay, China since 2015 after numerous blooms having been reported from other countries. In trying to identify the source of this newly observed HABs-forming species in China by sequencing the LSU rDNA for both field samples and clonal cultures, we noticed and thus further investigated high intrapopulational and intraindividual genetic diversities of the dinoflagellate. The D1-D6 region of the LSU rDNA (1,435 bases) was amplified from 7 field samples (pooled cells) and 11 clonal cultures, cloned, sequenced, and analyzed phylogenetically for 2,341 sequences obtained. All the numbers of sequences obtained from each clonal culture were far less than the estimated rDNA copy number in M. fulvescens. In the clone library, only one unique sequence was contained in all samples as the most dominant sequence. We found high intrapopulational and intraindividual genetic diversity in M. fulvescens as reflected in the number of polymorphic sites and unique sequences in the clone library for different field samples and clonal cultures in comparison to other species. The mean number of nucleotide differences of each sequence from different field samples and clonal cultures were 6.43 and 4.42 bases, respectively, with the highest being 132 bases, nearly 10%. The sequences with highest variability may be easily annotated as different species if they were obtained from environmental genomic studies because sequence-based species identification in meta-barcoding studies often use "97% identity" threshold. Based on that the mean and overall intrapopulational genetic diversity calculated for 7 field samples was equivalent to the mean and overall intraindividual variability for 11 clonal cultures in indices of genetic diversity, together with the result of AMOVA analysis, we infer that the variability within individual cells (i.e. variability among LSU rDNA polymorphic copies) caused both the intraindividual and intrapopulational genetic diversities observed in the M. fulvescens population, and a higher interpopulational diversity may exist among different geographic populations. The results provide an insightful basis for such a comprehensive interpopulational comparison and important implications for identifying species and establishing new taxa based on the similarity comparison to reference sequences deposited in databases.
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Affiliation(s)
- Siheng Lin
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhangxi Hu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Yunyan Deng
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Lixia Shang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11790, USA
| | - Ying Zhong Tang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
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25
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Description and phylogenetic analyses of ribosomal transcription units from species of Fasciolidae (Platyhelminthes: Digenea). J Helminthol 2020; 94:e136. [PMID: 32138801 DOI: 10.1017/s0022149x20000164] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Many members of Fasciolidae are common trematodes in cattle, buffaloes, sheep, elephants, pigs, with some capable of infecting humans also. In this study, the complete or near-complete sequences of ribosomal transcription unit (rTU or rDNA), each of Fasciola hepatica (Australia), Fascioloides jacksoni (Sri Lanka), Fasciolopsis buski (Vietnam) and three isolates of F. gigantica (Vietnam), were obtained and characterized. The full length of rDNA for each F. hepatica, 'hybrid' Fasciola sp., Fas. jacksoni and Fa. Buski, was 7657 bp, 7966 bp, 7781 bp and 8361 bp, with the complete intergenic spacer region (IGS) (862 bp, 1170 bp, 987 bp and 561 bp), respectively. The rDNA of two 'pure' F. gigantica isolates from Vietnam was 6794 bp with unsequenced IGS. For 28S rRNA genes the Fasciola spp. are equal, 1958 bp for 18S, 160 bp for 5.8S, 3863 bp and 454 bp for ITS1 but ITS2 differ by one nucleotide (Thymine) (359 or 360 bp). The ITS1 of the sensu lato Fa. buski has some distinguishable features, 286 bp for ITS2, 3862 bp for 28S and four repeat units of 356-361 bp each found in ITS1. The 28S rDNA analysis showed the lowest level of divergence (0-0.57%) between F. hepatica and F. gigantica and higher (2.23-2.62%) and highest (6-6.42%) for Fas. jacksoni and Fasciolopsis, respectively. The tree of 43 strains/species clearly produced a well-supported phylogeny, where 18 fasciolids consistently grouped, forming a discrete Fasciolidae clade, distinct from Philophthalmidae, Echinostomatidae and Echinochasmidae in Echinostomatoidea. Fascioloides jacksoni is outside Fasciola spp.: basal with Fas. magna, as previously demonstrated.
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Okie JG, Poret-Peterson AT, Lee ZM, Richter A, Alcaraz LD, Eguiarte LE, Siefert JL, Souza V, Dupont CL, Elser JJ. Genomic adaptations in information processing underpin trophic strategy in a whole-ecosystem nutrient enrichment experiment. eLife 2020; 9:49816. [PMID: 31989922 PMCID: PMC7028357 DOI: 10.7554/elife.49816] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 01/27/2020] [Indexed: 01/03/2023] Open
Abstract
Several universal genomic traits affect trade-offs in the capacity, cost, and efficiency of the biochemical information processing that underpins metabolism and reproduction. We analyzed the role of these traits in mediating the responses of a planktonic microbial community to nutrient enrichment in an oligotrophic, phosphorus-deficient pond in Cuatro Ciénegas, Mexico. This is one of the first whole-ecosystem experiments to involve replicated metagenomic assessment. Mean bacterial genome size, GC content, total number of tRNA genes, total number of rRNA genes, and codon usage bias in ribosomal protein sequences were all higher in the fertilized treatment, as predicted on the basis of the assumption that oligotrophy favors lower information-processing costs whereas copiotrophy favors higher processing rates. Contrasting changes in trait variances also suggested differences between traits in mediating assembly under copiotrophic versus oligotrophic conditions. Trade-offs in information-processing traits are apparently sufficiently pronounced to play a role in community assembly because the major components of metabolism-information, energy, and nutrient requirements-are fine-tuned to an organism's growth and trophic strategy.
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Affiliation(s)
- Jordan G Okie
- School of Earth and Space Exploration, Arizona State University, Tempe, United States
| | | | - Zarraz Mp Lee
- School of Life Sciences, Arizona State University, Tempe, United States
| | | | - Luis D Alcaraz
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis E Eguiarte
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Janet L Siefert
- Department of Statistics, Rice University, Houston, United States
| | - Valeria Souza
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | - James J Elser
- School of Life Sciences, Arizona State University, Tempe, United States.,Flathead Lake Biological Station, University of Montana, Polson, United States
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Georgiev O, Mishev K, Krasnikova M, Kitanova M, Dimitrova A, Karagyozov L. The Hordeum bulbosum 25S-18S rDNA region: comparison with Hordeum vulgare and other Triticeae. ACTA ACUST UNITED AC 2019; 74:319-328. [PMID: 31421048 DOI: 10.1515/znc-2018-0109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 07/18/2019] [Indexed: 11/15/2022]
Abstract
Hordeum vulgare and Hordeum bulbosum are two closely related barley species, which share a common H genome. H. vulgare has two nucleolar organizer regions (NORs), while the NOR of H. bulbosum is only one. We sequenced the 2.5 kb 25S-18S region in the rDNA of H. bulbosum and compared it to the same region in H. vulgare as well as to the other Triticeae. The region includes an intergenic spacer (IGS) with a number of subrepeats, a promoter, and an external transcribed spacer (5'ETS). The IGS of H. bulbosum downstream of 25S rRNA contains two 143-bp repeats and six 128-bp repeats. In contrast, the IGS in H. vulgare contains an array of seven 79-bp repeats and a varying number of 135-bp repeats. The 135-bp repeats in H. vulgare and the 128-bp repeats in H. bulbosum show similarity. Compared to H. vulgare, the 5'ETS of H. bulbosum is shorter. Additionally, the 5'ETS regions in H. bulbosum and H. vulgare diverged faster than in other Triticeae genera. Alignment of the Triticeae promoter sequences suggests that in Hordeum, as in diploid Triticum, transcription starts with guanine and not with adenine as it is in many other plants.
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Affiliation(s)
- Oleg Georgiev
- Institute of Molecular Life Sciences, University Zurich-Irchel, Winterthurer Str. 190, CH-8057 Zurich, Switzerland
| | - Kiril Mishev
- Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
| | - Maria Krasnikova
- Department of Genetics, Faculty of Biology, St. Kl. Ohridsky University of Sofia, 8 Dragan Tsankov bld., 1164 Sofia, Bulgaria
| | - Meglena Kitanova
- Department of Genetics, Faculty of Biology, St. Kl. Ohridsky University of Sofia, 8 Dragan Tsankov bld., 1164 Sofia, Bulgaria
| | - Anna Dimitrova
- Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria, Phone: +359 2 9792677, Fax: +359 2 9785516, E-mail:
| | - Luchezar Karagyozov
- Department of Genetics, Faculty of Biology, St. Kl. Ohridsky University of Sofia, 8 Dragan Tsankov bld., 1164 Sofia, Bulgaria
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Li B, Kremling KAG, Wu P, Bukowski R, Romay MC, Xie E, Buckler ES, Chen M. Coregulation of ribosomal RNA with hundreds of genes contributes to phenotypic variation. Genome Res 2018; 28:1555-1565. [PMID: 30166407 PMCID: PMC6169892 DOI: 10.1101/gr.229716.117] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 08/29/2018] [Indexed: 12/16/2022]
Abstract
Ribosomal repeats occupy 5% of a plant genome, yet there has been little study of their diversity in the modern age of genomics. Ribosomal copy number and expression variation present an opportunity to tap a novel source of diversity. In the present study, we estimated the ribosomal DNA (rDNA) copy number and ribosomal RNA (rRNA) expression for a population of maize inbred lines and investigated the potential role of rDNA and rRNA dosage in regulating global gene expression. Extensive variation was found in both ribosomal DNA copy number and ribosomal RNA expression among maize inbred lines. However, rRNA abundance was not consistent with the copy number of the rDNA. We have not found that the rDNA gene dosage has a regulatory role in gene expression; however, thousands of genes are identified to be coregulated with rRNA expression, including genes participating in ribosome biogenesis and other functionally relevant pathways. We further investigated the potential roles of copy number and the expression level of rDNA on agronomic traits and found that both correlated with flowering time but through different regulatory mechanisms. This comprehensive analysis suggested that rRNA expression variation is a valuable source of functional diversity that affects gene expression variation and field-based phenotypic changes.
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Affiliation(s)
- Bo Li
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China 100101
- Institute for Genomic Diversity, Cornell University, Ithaca, New York 14853, USA
| | - Karl A G Kremling
- School of Integrative Plant Sciences, Section of Plant Breeding and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Penghao Wu
- Institute for Genomic Diversity, Cornell University, Ithaca, New York 14853, USA
- College of Agronomy, Xinjiang Agriculture University, Urumqi, China 830052
| | - Robert Bukowski
- Bioinformatics Facility, Institute of Biotechnology, Cornell University, Ithaca, New York 14853, USA
| | - Maria C Romay
- Institute for Genomic Diversity, Cornell University, Ithaca, New York 14853, USA
| | - En Xie
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China 100101
| | - Edward S Buckler
- Institute for Genomic Diversity, Cornell University, Ithaca, New York 14853, USA
- School of Integrative Plant Sciences, Section of Plant Breeding and Genetics, Cornell University, Ithaca, New York 14853, USA
- US Department of Agriculture-Agricultural Research Service (USDA-ARS), Ithaca, New York 14853, USA
| | - Mingsheng Chen
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China 100101
- University of Chinese Academy of Sciences, Beijing, China 100049
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29
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nrDNA:mtDNA copy number ratios as a comparative metric for evolutionary and conservation genetics. Heredity (Edinb) 2018; 121:105-111. [PMID: 29752470 DOI: 10.1038/s41437-018-0088-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/17/2018] [Accepted: 04/13/2018] [Indexed: 11/09/2022] Open
Abstract
Identifying genetic cues of functional relevance is key to understanding the drivers of evolution and increasingly important for the conservation of biodiversity. This study introduces nuclear ribosomal DNA (nrDNA) to mitochondrial DNA (mtDNA) copy number ratios as a metric with which to screen for this functional genetic variation prior to more extensive omics analyses. To illustrate the metric, quantitative PCR was used to estimate nrDNA (18S) to mtDNA (16S) copy number ratios in muscle tissue from samples of two zooplankton species: Salpa thompsoni caught near Elephant Island (Southern Ocean) and S. fusiformis sampled off Gough Island (South Atlantic). Average 18S:16S ratios in these samples were 9:1 and 3:1, respectively. nrDNA 45S arrays and mitochondrial genomes were then deep sequenced to uncover the sources of intra-individual genetic variation underlying these 18S:16S copy number differences. The deep sequencing profiles obtained were consistent with genetic changes resulting from adaptive processes, including an expansion of nrDNA and damage to mtDNA in S. thompsoni, potentially in response to the polar environment. Beyond this example from zooplankton, nrDNA:mtDNA copy number ratios offer a promising metric to help identify genetic variation of functional relevance in animals more broadly.
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30
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Gong L, Shi W, Yang M, Kong X. Marked intra-genomic variation and pseudogenes in the ITS1-5.8S-ITS2 rDNA of Symphurus plagiusa (Pleuronectiformes: Cynoglossidae). ANIM BIOL 2018. [DOI: 10.1163/15707563-17000134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
The eukaryotic ribosomal DNA (rDNA) cluster consists of multiple copies of three genes (18S, 5.8S, and 28S rDNA) and two internal transcribed spacers (ITS1 and ITS2). In recent years, an increasing number of rDNA sequence polymorphisms have been identified in numerous species. In the present study, we provide 33 complete ITS (ITS1-5.8S-ITS2) sequences from two Symphurus plagiusa individuals. To the best of our knowledge, these sequences are the first detailed information on ITS sequences in Pleuronectiformes. Here, two divergent types (Type A and B) of the ITS1-5.8S-ITS2 rDNA sequence were found, which mainly differ in sequence length, GC content, nucleotide diversity (π), secondary structure and minimum free energy. The ITS1-5.8S-ITS2 rDNA sequence of Type B was speculated to be a putative pseudogene according to pseudogene identification criteria. Cluster analysis showed that sequences from the same type clustered into one group and two major groups were formed. The high degree of ITS1-5.8S-ITS2 sequence polymorphism at the intra-specific level indicated that the S. plagiusa genome has evolved in a non-concerted evolutionary manner. These results not only provide useful data for ribosomal pseudogene identification, but also further contribute to the study of rDNA evolution in teleostean genomes.
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Affiliation(s)
- Li Gong
- 1National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Zhejiang Ocean University, 316022, Zhoushan, China
- 2National Engineering Research Center for Facilitated Marine Aquaculture, Marine Science and Technology College, Zhejiang Ocean University, 316022, Zhoushan, China
| | - Wei Shi
- 3Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510000, Guangzhou, China
- 4South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, 510000, Guangzhou, China
| | - Min Yang
- 3Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510000, Guangzhou, China
- 4South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, 510000, Guangzhou, China
| | - Xiaoyu Kong
- 3Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510000, Guangzhou, China
- 4South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, 510000, Guangzhou, China
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Martínez-González CR, Ramírez-Mendoza R, Jiménez-Ramírez J, Gallegos-Vázquez C, Luna-Vega I. Improved method for genomic DNA extraction for Opuntia Mill. (Cactaceae). PLANT METHODS 2017; 13:82. [PMID: 29046708 PMCID: PMC5637266 DOI: 10.1186/s13007-017-0234-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 10/03/2017] [Indexed: 05/25/2023]
Abstract
BACKGROUND Genomic DNA extracted from species of Cactaceae is often contaminated with significant amounts of mucilage and pectin. Pectin is one of the main components of cellular walls, whereas mucilage is a complex polysaccharide with a ramified structure. Thus, pectin- and mucilage-free extraction of DNA is a key step for further downstream PCR-based analyses. RESULTS We tested our DNA extraction method on cladode tissue (juvenile, adult, and herbaria exemplars) of 17 species of Opuntia Mill., which are characterized by a large quantity of pectin and mucilage. CONCLUSION We developed a method for the extraction of gDNA free of inhibitory compounds common in species of Opuntia Mill., such as pectin and mucilage. Compared to previously extraction protocols, our method produced higher yields of high-quality genomic DNA.
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Affiliation(s)
- César Ramiro Martínez-González
- Laboratorio de Biogeografía y Sistemática, Departamento de Biología, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, 04510 Mexico City, México
| | - Rosario Ramírez-Mendoza
- Laboratorio de Biotecnología de Semillas, Colegio de Postgraduados, Carretera México-Texcoco, 56230 Estado de México, México
| | - Jaime Jiménez-Ramírez
- Herbario de la Facultad de Ciencias, Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, 04510 Mexico City, México
| | - Clemente Gallegos-Vázquez
- Centro Regional Universitario Centro Norte, Universidad Autónoma Chapingo, Cruz del Sur núm. 100, Colonia Constelación, El Orito, 98085 Zacatecas, Zacatecas México
| | - Isolda Luna-Vega
- Laboratorio de Biogeografía y Sistemática, Departamento de Biología, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, 04510 Mexico City, México
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Bélanger-Lépine F, Leung C, Glémet H, Angers B. Balancing selection on the number of repeats in the ribosomal intergenic spacer present in naturally occurring yellow perch (Perca flavescens) populations. Genome 2017; 61:1-6. [PMID: 28950069 DOI: 10.1139/gen-2017-0061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ribosomal intergenic spacer (IGS), responsible for the rate of transcription of rRNA genes, is associated with the growth and fecundity of individuals. A previous study of IGS length variants in a yellow perch (Perca flavescens) population revealed the presence of two predominant alleles differing by 1 kb due to variation in the number of repeat units. This study aims to assess whether length variation of IGS is the result of selection in natural populations. Length variation of IGS and 11 neutral microsatellite loci were assessed in geographically distant yellow perch populations. Most populations displayed the very same IGS alleles; they did not differ in frequencies among populations and the FST was not significantly different from zero. In contrast, diversity at microsatellite loci was high and differed among populations (FST = 0.18). Selection test based on FST identified IGS as a significant outlier from neutral expectations for population differentiation. Heterozygote excess was also detected in one specific cohort, suggesting temporal variation in the selection regime. While the exact mechanism remains to be specified, together the results of this study support the contention that balancing selection is acting to maintain two distinct IGS alleles in natural fish populations.
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Affiliation(s)
- Frédérique Bélanger-Lépine
- a Département des sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada; GRIL - Groupe de recherche interuniversitaire en limnologie et en environnement aquatique
| | - Christelle Leung
- b Department of Biological Sciences, Université de Montréal, Montréal, QC H3C 3J7, Canada; GRIL - Groupe de recherche interuniversitaire en limnologie et en environnement aquatique
| | - Hélène Glémet
- a Département des sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada; GRIL - Groupe de recherche interuniversitaire en limnologie et en environnement aquatique
| | - Bernard Angers
- b Department of Biological Sciences, Université de Montréal, Montréal, QC H3C 3J7, Canada; GRIL - Groupe de recherche interuniversitaire en limnologie et en environnement aquatique
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Metabolic Flexibility Underpins Growth Capabilities of the Fastest Growing Alga. Curr Biol 2017; 27:2559-2567.e3. [PMID: 28803869 DOI: 10.1016/j.cub.2017.07.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/02/2017] [Accepted: 07/06/2017] [Indexed: 11/21/2022]
Abstract
The factors rate-limiting growth of photosynthetic organisms under optimal conditions are controversial [1-8]. Adaptation to extreme environments is usually accompanied by reduced performance under optimal conditions [9, 10]. However, the green alga Chlorella ohadii, isolated from a harsh desert biological soil crust [11-17], does not obey this rule. In addition to resistance to photodamage [17, 18], it performs the fastest growth ever reported for photosynthetic eukaryotes. A multiphasic growth pattern (very fast growth [phase I], followed by growth retardation [phase II] and additional fast growth [phase III]) observed under constant illumination and temperature indicates synchronization of the algal population. Large physiological changes at transitions between growth phases suggest metabolic shifts. Indeed, metabolome analyses at points along the growth phases revealed large changes in the levels of many metabolites during growth with an overall rise during phase I and decline in phase II. Multivariate analysis of the metabolome data highlighted growth phase as the main factor contributing to observed metabolite variance. The analyses identified putrescine as the strongest predictive metabolite for growth phase and a putative growth regulator. Indeed, extracellular additions of polyamines strongly affected the growth rate in phase I and the growth arrest in phase II, with a marked effect on O2 exchange. Our data implicate polyamines as the signals harmonizing metabolic shifts and suggest that metabolic flexibility enables the immense growth capabilities of C. ohadii. The data provide a new dimension to current models focusing on growth-limiting processes in photosynthetic organisms where the anabolic and catabolic metabolisms must be strictly regulated.
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Fu R, Gong J. Single Cell Analysis Linking Ribosomal (r)DNA and rRNA Copy Numbers to Cell Size and Growth Rate Provides Insights into Molecular Protistan Ecology. J Eukaryot Microbiol 2017; 64:885-896. [PMID: 28499076 PMCID: PMC5697653 DOI: 10.1111/jeu.12425] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 04/03/2017] [Accepted: 05/02/2017] [Indexed: 11/30/2022]
Abstract
Ribosomal (r)RNA and rDNA have been golden molecular markers in microbial ecology. However, it remains poorly understood how ribotype copy number (CN)‐based characteristics are linked with diversity, abundance, and activity of protist populations and communities observed at organismal levels. Here, we applied a single‐cell approach to quantify ribotype CNs in two ciliate species reared at different temperatures. We found that in actively growing cells, the per‐cell rDNA and rRNA CNs scaled with cell volume (CV) to 0.44 and 0.58 powers, respectively. The modeled rDNA and rRNA concentrations thus appear to be much higher in smaller than in larger cells. The observed rRNA:rDNA ratio scaled with CV0.14. The maximum growth rate could be well predicted by a combination of per‐cell ribotype CN and temperature. Our empirical data and modeling on single‐cell ribotype scaling are in agreement with both the metabolic theory of ecology and the growth rate hypothesis, providing a quantitative framework for linking cellular rDNA and rRNA CNs with body size, growth (activity), and biomass stoichiometry. This study also demonstrates that the expression rate of rRNA genes is constrained by cell size, and favors biomass rather than abundance‐based interpretation of quantitative ribotype data in population and community ecology of protists.
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Affiliation(s)
- Rao Fu
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jun Gong
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Laboratory of Microbial Ecology and Matter Cycles, School of Marine Sciences, Sun Yat-Sen University, Zhuhai, 519082, China
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Groendahl S, Fink P. High dietary quality of non-toxic cyanobacteria for a benthic grazer and its implications for the control of cyanobacterial biofilms. BMC Ecol 2017; 17:20. [PMID: 28521755 PMCID: PMC5437396 DOI: 10.1186/s12898-017-0130-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 05/09/2017] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Mass occurrences of cyanobacteria frequently cause detrimental effects to the functioning of aquatic ecosystems. Consequently, attempts haven been made to control cyanobacterial blooms through naturally co-occurring herbivores. Control of cyanobacteria through herbivores often appears to be constrained by their low dietary quality, rather than by the possession of toxins, as also non-toxic cyanobacteria are hardly consumed by many herbivores. It was thus hypothesized that the consumption of non-toxic cyanobacteria may be improved when complemented with other high quality prey. We conducted a laboratory experiment in which we fed the herbivorous freshwater gastropod Lymnaea stagnalis single non-toxic cyanobacterial and unialgal diets or a mixed diet to test if diet-mixing may enable these herbivores to control non-toxic cyanobacterial mass abundances. RESULTS The treatments where L. stagnalis were fed non-toxic cyanobacteria and a mixed diet provided a significantly higher shell and soft-body growth rate than the average of all single algal, but not the non-toxic cyanobacterial diets. However, the increase in growth provided by the non-toxic cyanobacteria diets could not be related to typical determinants of dietary quality such as toxicity, nutrient stoichiometry or essential fatty acid content. CONCLUSIONS These results strongly contradict previous research which describes non-toxic cyanobacteria as a low quality food resource for freshwater herbivores in general. Our findings thus have strong implications to gastropod-cyanobacteria relationships and suggest that freshwater gastropods may be able to control mass occurrences of benthic non-toxic cyanobacteria, frequently observed in eutrophied water bodies worldwide.
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Affiliation(s)
- Sophie Groendahl
- Cologne Biocenter, Workgroup Aquatic Chemical Ecology, University of Cologne, Zuelpicher Strasse 47b, 50674 Koeln, Germany
| | - Patrick Fink
- Cologne Biocenter, Workgroup Aquatic Chemical Ecology, University of Cologne, Zuelpicher Strasse 47b, 50674 Koeln, Germany
- Institute for Zoomorphology and Cell Biology, Heinrich-Heine University of Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany
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Rebollar EA, Woodhams DC, LaBumbard B, Kielgast J, Harris RN. Prevalence and pathogen load estimates for the fungus Batrachochytrium dendrobatidis are impacted by ITS DNA copy number variation. DISEASES OF AQUATIC ORGANISMS 2017; 123:213-226. [PMID: 28322208 DOI: 10.3354/dao03097] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The ribosomal gene complex is a multi-copy region that is widely used for phylogenetic analyses of organisms from all 3 domains of life. In fungi, the copy number of the internal transcribed spacer (ITS) is used to detect abundance of pathogens causing diseases such as chytridiomycosis in amphibians and white nose syndrome in bats. Chytridiomycosis is caused by the fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), and is responsible for declines and extinctions of amphibians worldwide. Over a decade ago, a qPCR assay was developed to determine Bd prevalence and pathogen load. Here, we demonstrate the effect that ITS copy number variation in Bd strains can have on the estimation of prevalence and pathogen load. We used data sets from different amphibian species to simulate how ITS copy number affects prevalence and pathogen load. In addition, we tested 2 methods (gBlocks® synthetic standards and digital PCR) to determine ITS copy number in Bd strains. Our results show that assumptions about the ITS copy number can lead to under- or overestimation of Bd prevalence and pathogen load. The use of synthetic standards replicated previously published estimates of ITS copy number, whereas dPCR resulted in estimates that were consistently lower than previously published estimates. Standardizing methods will assist with comparison across studies and produce reliable estimates of prevalence and pathogen load in the wild, while using the same Bd strain for exposure experiments and zoospore standards in qPCR remains the best method for estimating parameters used in epidemiological studies.
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Affiliation(s)
- Eria A Rebollar
- Biology Department, James Madison University, 951 Carrier Dr., MSC 7801, Harrisonburg, Virginia 22807, USA
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Le TH, Nguyen KT, Nguyen NTB, Doan HTT, Dung DT, Blair D. The ribosomal transcription units of Haplorchis pumilio and H. taichui and the use of 28S rDNA sequences for phylogenetic identification of common heterophyids in Vietnam. Parasit Vectors 2017; 10:17. [PMID: 28069063 PMCID: PMC5223338 DOI: 10.1186/s13071-017-1968-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 01/04/2017] [Indexed: 11/10/2022] Open
Abstract
Background Heterophyidiasis is now a major public health threat in many tropical countries. Species in the trematode family Heterophyidae infecting humans include Centrocestus formosanus, Haplorchis pumilio, H. taichui, H. yokogawai, Procerovum varium and Stellantchasmus falcatus. For molecular phylogenetic and systematic studies on trematodes, we need more prospective markers for taxonomic identification and classification. This study provides near-complete ribosomal transcription units (rTU) from Haplorchis pumilio and H. taichui and demonstrates the use of 28S rDNA sequences for identification and phylogenetic analysis. Results The near-complete ribosomal transcription units (rTU), consisting of 18S, ITS1, 5.8S, ITS2 and 28S rRNA genes and spacers, from H. pumilio and H. taichui from human hosts in Vietnam, were determined and annotated. Sequence analysis revealed tandem repetitive elements in ITS1 in H. pumilio and in ITS2 in H. taichui. A phylogenetic tree inferred from 28S rDNA sequences of 40 trematode strains/species, including 14 Vietnamese heterophyid individuals, clearly confirmed the status of each of the Vietnamese species: Centrocestus formosanus, Haplorchis pumilio, H. taichui, H. yokogawai, Procerovum varium and Stellantchasmus falcatus. However, the family Heterophyidae was clearly not monophyletic, with some genera apparently allied with other families within the superfamily Opisthorchioidea (i.e. Cryptogonimidae and Opisthorchiidae). These families and their constituent genera require substantial re-evaluation using a combination of morphological and molecular data. Our new molecular data will assist in such studies. Conclusions The 28S rDNA sequences are conserved among individuals within a species but varied between genera. Based on analysis of 40 28S rDNA sequences representing 19 species in the superfamily Opisthorchioidea and an outgroup taxon (Alaria alata, family Diplostomidae), six common human pathogenic heterophyids were identified and clearly resolved. The phylogenetic tree inferred from these sequences again confirmed anomalies in molecular placement of some members of the family Heterophyidae and demonstrates the need for reappraisal of the entire superfamily Opisthorchioidea. The new sequences provided here supplement those already available in public databases and add to the array of molecular tools that can be used for the diagnosis of heterophyid species in human and animal infections.
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Affiliation(s)
- Thanh Hoa Le
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18. Hoang Quoc Viet Rd,, Cau Giay, Hanoi, Vietnam.
| | - Khue Thi Nguyen
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18. Hoang Quoc Viet Rd,, Cau Giay, Hanoi, Vietnam
| | - Nga Thi Bich Nguyen
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18. Hoang Quoc Viet Rd,, Cau Giay, Hanoi, Vietnam
| | - Huong Thi Thanh Doan
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18. Hoang Quoc Viet Rd,, Cau Giay, Hanoi, Vietnam
| | - Do Trung Dung
- Department of Parasitology, National Institute of Malariology, Parasitology and Entomology, Luong The Vinh Rd,, Thanh Xuan, Hanoi, Vietnam
| | - David Blair
- College of Science and Engineering, James Cook University, Townsville, Australia
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Ata AETM, Abd El-Twab MH, Helmey RK, Dahy H. Phylogenetic relationships among Egyptian species of Anthemideae (Asteraceae) using ITS markers. CHROMOSOME BOTANY 2017; 12:1-6. [DOI: 10.3199/iscb.12.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Affiliation(s)
| | | | - Rasha Kamal Helmey
- Department of Botany and Microbiology, Faculty of Science, Minia University, Egypt
| | - Hadeer Dahy
- Department of Botany and Microbiology, Faculty of Science, Minia University, Egypt
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Taylor DL, Walters WA, Lennon NJ, Bochicchio J, Krohn A, Caporaso JG, Pennanen T. Accurate Estimation of Fungal Diversity and Abundance through Improved Lineage-Specific Primers Optimized for Illumina Amplicon Sequencing. Appl Environ Microbiol 2016; 82:7217-7226. [PMID: 27736792 PMCID: PMC5118932 DOI: 10.1128/aem.02576-16] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 10/04/2016] [Indexed: 11/20/2022] Open
Abstract
While high-throughput sequencing methods are revolutionizing fungal ecology, recovering accurate estimates of species richness and abundance has proven elusive. We sought to design internal transcribed spacer (ITS) primers and an Illumina protocol that would maximize coverage of the kingdom Fungi while minimizing nontarget eukaryotes. We inspected alignments of the 5.8S and large subunit (LSU) ribosomal genes and evaluated potential primers using PrimerProspector. We tested the resulting primers using tiered-abundance mock communities and five previously characterized soil samples. We recovered operational taxonomic units (OTUs) belonging to all 8 members in both mock communities, despite DNA abundances spanning 3 orders of magnitude. The expected and observed read counts were strongly correlated (r = 0.94 to 0.97). However, several taxa were consistently over- or underrepresented, likely due to variation in rRNA gene copy numbers. The Illumina data resulted in clustering of soil samples identical to that obtained with Sanger sequence clone library data using different primers. Furthermore, the two methods produced distance matrices with a Mantel correlation of 0.92. Nonfungal sequences comprised less than 0.5% of the soil data set, with most attributable to vascular plants. Our results suggest that high-throughput methods can produce fairly accurate estimates of fungal abundances in complex communities. Further improvements might be achieved through corrections for rRNA copy number and utilization of standardized mock communities. IMPORTANCE Fungi play numerous important roles in the environment. Improvements in sequencing methods are providing revolutionary insights into fungal biodiversity, yet accurate estimates of the number of fungal species (i.e., richness) and their relative abundances in an environmental sample (e.g., soil, roots, water, etc.) remain difficult to obtain. We present improved methods for high-throughput Illumina sequencing of the species-diagnostic fungal ribosomal marker gene that improve the accuracy of richness and abundance estimates. The improvements include new PCR primers and library preparation, validation using a known mock community, and bioinformatic parameter tuning.
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Affiliation(s)
- D Lee Taylor
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - William A Walters
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, USA
| | - Niall J Lennon
- Broad Institute of MIT & Harvard, Cambridge, Massachusetts, USA
| | | | - Andrew Krohn
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - J Gregory Caporaso
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Taina Pennanen
- Natural Resources Institute Finland (Luke), Vantaa, Finland
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Takahashi-Kariyazono S, Gojobori J, Satta Y, Sakai K, Terai Y. Acropora digitifera Encodes the Largest Known Family of Fluorescent Proteins that Has Persisted during the Evolution of Acropora Species. Genome Biol Evol 2016; 8:3271-3283. [PMID: 27920057 PMCID: PMC5203795 DOI: 10.1093/gbe/evw265] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Fluorescent proteins (FPs) are well known and broadly used as bio-imaging markers in molecular biology research. Many FP genes were cloned from anthozoan species and it was suggested that multi-copies of these genes are present in their genomes. However, the full complement of FP genes in any single coral species remained unidentified. In this study, we analyzed the FP genes in two stony coral species. FP cDNA sequences from Acropora digitifera and Acropora tenuis revealed the presence of a multi-gene family with an unexpectedly large number of genes, separated into short-/middle-wavelength emission (S/MWE), middle-/long-wavelength emission (M/LWE), and chromoprotein (CP) clades. FP gene copy numbers in the genomes of four A. digitifera colonies were estimated as 16–22 in the S/MWE, 3–6 in the M/LWE, and 8–12 in the CP clades, and, in total, 35, 31, 33, and 33 FP gene copies per individual shown by quantitative PCR. To the best of our knowledge, these are the largest sets of FP genes per genome. The fluorescent light produced by recombinant protein products encoded by the newly isolated genes explained the fluorescent range of live A. digitifera, suggesting that the high copy multi-FP gene family generates coral fluorescence. The functionally diverse multi-FP gene family must have existed in the ancestor of Acropora species, as suggested by molecular phylogenetic and evolutionary analyses. The persistence of a diverse function and high copy number multi-FP gene family may indicate the biological importance of diverse fluorescence emission and light absorption in Acropora species.
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Affiliation(s)
- Shiho Takahashi-Kariyazono
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan
| | - Jun Gojobori
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan
| | - Yoko Satta
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan
| | - Kazuhiko Sakai
- Department of Coral Reef and Biological Science, Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, 3422 Sesoko, Motobu, Okinawa 905-0227, Japan
| | - Yohey Terai
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan
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Havlová K, Dvořáčková M, Peiro R, Abia D, Mozgová I, Vansáčová L, Gutierrez C, Fajkus J. Variation of 45S rDNA intergenic spacers in Arabidopsis thaliana. PLANT MOLECULAR BIOLOGY 2016; 92:457-471. [PMID: 27531496 DOI: 10.1007/s11103-016-0524-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/03/2016] [Indexed: 05/28/2023]
Abstract
Approximately seven hundred 45S rRNA genes (rDNA) in the Arabidopsis thaliana genome are organised in two 4 Mbp-long arrays of tandem repeats arranged in head-to-tail fashion separated by an intergenic spacer (IGS). These arrays make up 5 % of the A. thaliana genome. IGS are rapidly evolving sequences and frequent rearrangements inside the rDNA loci have generated considerable interspecific and even intra-individual variability which allows to distinguish among otherwise highly conserved rRNA genes. The IGS has not been comprehensively described despite its potential importance in regulation of rDNA transcription and replication. Here we describe the detailed sequence variation in the complete IGS of A. thaliana WT plants and provide the reference/consensus IGS sequence, as well as genomic DNA analysis. We further investigate mutants dysfunctional in chromatin assembly factor-1 (CAF-1) (fas1 and fas2 mutants), which are known to have a reduced number of rDNA copies, and plant lines with restored CAF-1 function (segregated from a fas1xfas2 genetic background) showing major rDNA rearrangements. The systematic rDNA loss in CAF-1 mutants leads to the decreased variability of the IGS and to the occurrence of distinct IGS variants. We present for the first time a comprehensive and representative set of complete IGS sequences, obtained by conventional cloning and by Pacific Biosciences sequencing. Our data expands the knowledge of the A. thaliana IGS sequence arrangement and variability, which has not been available in full and in detail until now. This is also the first study combining IGS sequencing data with RFLP analysis of genomic DNA.
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Affiliation(s)
- Kateřina Havlová
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Martina Dvořáčková
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
- Institute of Biophysics ASCR, v.v.i., Královopolská 135, 61265, Brno, Czech Republic.
| | - Ramon Peiro
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Madrid, 28049, Spain
| | - David Abia
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Madrid, 28049, Spain
| | - Iva Mozgová
- Faculty of Science, Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Masaryk University, Kotlářská 2, 61137, Brno, Czech Republic
| | - Lenka Vansáčová
- Faculty of Science, Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Masaryk University, Kotlářská 2, 61137, Brno, Czech Republic
| | - Crisanto Gutierrez
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Madrid, 28049, Spain
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
- Faculty of Science, Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Masaryk University, Kotlářská 2, 61137, Brno, Czech Republic.
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Rosato M, Kovařík A, Garilleti R, Rosselló JA. Conserved Organisation of 45S rDNA Sites and rDNA Gene Copy Number among Major Clades of Early Land Plants. PLoS One 2016; 11:e0162544. [PMID: 27622766 PMCID: PMC5021289 DOI: 10.1371/journal.pone.0162544] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 08/24/2016] [Indexed: 11/26/2022] Open
Abstract
Genes encoding ribosomal RNA (rDNA) are universal key constituents of eukaryotic genomes, and the nuclear genome harbours hundreds to several thousand copies of each species. Knowledge about the number of rDNA loci and gene copy number provides information for comparative studies of organismal and molecular evolution at various phylogenetic levels. With the exception of seed plants, the range of 45S rDNA locus (encoding 18S, 5.8S and 26S rRNA) and gene copy number variation within key evolutionary plant groups is largely unknown. This is especially true for the three earliest land plant lineages Marchantiophyta (liverworts), Bryophyta (mosses), and Anthocerotophyta (hornworts). In this work, we report the extent of rDNA variation in early land plants, assessing the number of 45S rDNA loci and gene copy number in 106 species and 25 species, respectively, of mosses, liverworts and hornworts. Unexpectedly, the results show a narrow range of ribosomal locus variation (one or two 45S rDNA loci) and gene copies not present in vascular plant lineages, where a wide spectrum is recorded. Mutation analysis of whole genomic reads showed higher (3-fold) intragenomic heterogeneity of Marchantia polymorpha (Marchantiophyta) rDNA compared to Physcomitrella patens (Bryophyta) and two angiosperms (Arabidopsis thaliana and Nicotiana tomentosifomis) suggesting the presence of rDNA pseudogenes in its genome. No association between phylogenetic position, taxonomic adscription and the number of rDNA loci and gene copy number was found. Our results suggest a likely evolutionary rDNA stasis during land colonisation and diversification across 480 myr of bryophyte evolution. We hypothesise that strong selection forces may be acting against ribosomal gene locus amplification. Despite showing a predominant haploid phase and infrequent meiosis, overall rDNA homogeneity is not severely compromised in bryophytes.
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Affiliation(s)
- Marcela Rosato
- Jardín Botánico, ICBiBE-Unidad Asociada CSIC, Universidad de Valencia, c/Quart 80, E-46008, Valencia, Spain
| | - Aleš Kovařík
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, CZ–61265, Czech Republic
| | - Ricardo Garilleti
- Departamento de Botánica, Facultad de Farmacia, Universidad de Valencia, E-46100, Burjassot, Spain
| | - Josep A. Rosselló
- Jardín Botánico, ICBiBE-Unidad Asociada CSIC, Universidad de Valencia, c/Quart 80, E-46008, Valencia, Spain
- Marimurtra Bot. Garden, Carl Faust Fdn., PO Box 112, E-17300, Blanes, Catalonia, Spain
- * E-mail:
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Soil bacterial endemism and potential functional redundancy in natural broadleaf forest along a latitudinal gradient. Sci Rep 2016; 6:28819. [PMID: 27357005 PMCID: PMC4928066 DOI: 10.1038/srep28819] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 04/05/2016] [Indexed: 11/21/2022] Open
Abstract
Microorganisms play key roles in ecosystem processes and biogeochemical cycling, however, the relationship between soil microbial taxa diversity and their function in natural ecosystems is largely unknown. To determine how soil bacteria community and function are linked from the local to regional scale, we studied soil bacteria community composition, potential function and environmental conditions in natural and mature broadleaf forests along a latitudinal gradient in China, using the Illumina 16S rRNA sequencing and GeoChip technologies. The results showed strong biogeographic endemism pattern in soil bacteria were existed, and the spatial distance and climatic variables were the key controlling factors for this pattern. Therefore, dispersal limitation and environmental selection may represent two key processes in generating and maintaining the soil bacterial biogeographic pattern. By contrast, the soil bacterial potential function is highly convergent along the latitudinal gradient and there were highly differing bacterial community compositions, and the soil chemistry may include the main factors active in shaping the soil bacterial potential function. Therefore, the soil bacterial potential function may be affected by local gradients in resource availability, and predicting soil bacterial potential function requires knowledge of abiotic and biotic environmental factors.
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Lee YJ, Lee R, Lee SH, Yim SS, Jeong KJ. Enhanced secretion of recombinant proteins via signal recognition particle (SRP)-dependent secretion pathway by deletion of rrsE in Escherichia coli. Biotechnol Bioeng 2016; 113:2453-61. [PMID: 27111103 DOI: 10.1002/bit.25997] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/07/2016] [Accepted: 04/21/2016] [Indexed: 12/29/2022]
Abstract
Although signal recognition particle (SRP)-dependent secretion pathway, which is characterized by co-translational translocation, helps prevent cytoplasmic aggregation of proteins before secretion, its limited capacity for the protein secretion is a major hurdle for utilizing the pathway as an attractive route for secretory production of recombinant proteins. Therefore, we developed an Escherichia coli mutant, whose efficiency of secretion via the SRP pathway was dramatically increased. First, we developed a novel FACS-based screening system by combining a periplasmic display system (PECS) and direct fluorescent labeling with the organoarsenic compound, FlAsH-EDT2 . With this screening system, transposon-insertion library of E. coli was screened, and then we isolated mutants which exhibited higher protein production through the SRP pathway than the parental strain. From the genetic analysis, we found that all isolated mutants had the same mutation-disruption of the 16S rRNA gene (rrsE). The positive effect of rrsE deficiency on protein secretion via the SRP pathway was successfully demonstrated using various model proteins including endogenous SRP-dependent proteins, antibodies, and G protein-coupled receptor. For the large-scale production of IgG and GPCR, we performed fed-batch cultivation with the rrsE-deficient mutant, and very high yields of IgG (0.4 g/L) and GPCR (1.4 g/L) were obtained. Biotechnol. Bioeng. 2016;113: 2453-2461. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yong Jae Lee
- Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Roojin Lee
- Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Se Hwa Lee
- Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Sung Sun Yim
- Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Ki Jun Jeong
- Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea. .,KAIST Institute for the BioCentury, Yuseong-gu, Daejeon, Republic of Korea.
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André M, Reghin S, Boussard E, Lempereur L, Maisonneuve S. Universal real-time PCR assay for quantitation and size evaluation of residual cell DNA in human viral vaccines. Biologicals 2016; 44:139-49. [DOI: 10.1016/j.biologicals.2016.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 11/26/2015] [Accepted: 03/05/2016] [Indexed: 12/15/2022] Open
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Abstract
During meiosis, numerous DNA double-strand breaks (DSBs) are formed as part of the normal developmental program. This seemingly destructive behavior is necessary for successful meiosis, since repair of the DSBs through homologous recombination (HR) helps to produce physical links between the homologous chromosomes essential for correct chromosome segregation later in meiosis. However, DSB formation at such a massive scale also introduces opportunities to generate gross chromosomal rearrangements. In this review, we explore ways in which meiotic DSBs can result in such genomic alterations.
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Kakou B, Angers B, Glémet H. Extensive length variation in the ribosomal DNA intergenic spacer of yellow perch (Perca flavescens). Genome 2016; 59:149-58. [PMID: 26841134 DOI: 10.1139/gen-2015-0114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The intergenic spacer (IGS) is located between ribosomal RNA (rRNA) gene copies. Within the IGS, regulatory elements for rRNA gene transcription are found, as well as a varying number of other repetitive elements that are at the root of IGS length heterogeneity. This heterogeneity has been shown to have a functional significance through its effect on growth rate. Here, we present the structural organization of yellow perch (Perca flavescens) IGS based on its entire sequence, as well as the IGS length variation within a natural population. Yellow perch IGS structure has four discrete regions containing tandem repeat elements. For three of these regions, no specific length class was detected as allele size was seemingly normally distributed. However, for one repeat region, PCR amplification uncovered the presence of two distinctive IGS variants representing a length difference of 1116 bp. This repeat region was also devoid of any CpG sites despite a high GC content. Balanced selection may be holding the alleles in the population and would account for the high diversity of length variants observed for adjacent regions. Our study is an important precursor for further work aiming to assess the role of IGS length variation in influencing growth rate in fish.
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Affiliation(s)
- Bidénam Kakou
- a Département des sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada
| | - Bernard Angers
- b Department of Biological Sciences, Université de Montréal, Montréal, QC H3C 3J7, Canada.,c GRIL - Groupe de recherche interuniversitaire en limnologie et en environnement aquatique
| | - Hélène Glémet
- a Département des sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada.,c GRIL - Groupe de recherche interuniversitaire en limnologie et en environnement aquatique
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Valdivia-Anistro JA, Eguiarte-Fruns LE, Delgado-Sapién G, Márquez-Zacarías P, Gasca-Pineda J, Learned J, Elser JJ, Olmedo-Alvarez G, Souza V. Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem. Front Microbiol 2016; 6:1486. [PMID: 26779143 PMCID: PMC4700252 DOI: 10.3389/fmicb.2015.01486] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 12/09/2015] [Indexed: 12/28/2022] Open
Abstract
The ribosomal RNA (rrn) operon is a key suite of genes related to the production of protein synthesis machinery and thus to bacterial growth physiology. Experimental evidence has suggested an intrinsic relationship between the number of copies of this operon and environmental resource availability, especially the availability of phosphorus (P), because bacteria that live in oligotrophic ecosystems usually have few rrn operons and a slow growth rate. The Cuatro Ciénegas Basin (CCB) is a complex aquatic ecosystem that contains an unusually high microbial diversity that is able to persist under highly oligotrophic conditions. These environmental conditions impose a variety of strong selective pressures that shape the genome dynamics of their inhabitants. The genus Bacillus is one of the most abundant cultivable bacterial groups in the CCB and usually possesses a relatively large number of rrn operon copies (6–15 copies). The main goal of this study was to analyze the variation in the number of rrn operon copies of Bacillus in the CCB and to assess their growth-related properties as well as their stoichiometric balance (N and P content). We defined 18 phylogenetic groups within the Bacilli clade and documented a range of from six to 14 copies of the rrn operon. The growth dynamic of these Bacilli was heterogeneous and did not show a direct relation to the number of operon copies. Physiologically, our results were not consistent with the Growth Rate Hypothesis, since the copies of the rrn operon were decoupled from growth rate. However, we speculate that the diversity of the growth properties of these Bacilli as well as the low P content of their cells in an ample range of rrn copy number is an adaptive response to oligotrophy of the CCB and could represent an ecological mechanism that allows these taxa to coexist. These findings increase the knowledge of the variability in the number of copies of the rrn operon in the genus Bacillus and give insights about the physiology of this bacterial group under extreme oligotrophic conditions.
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Affiliation(s)
- Jorge A Valdivia-Anistro
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México Coyoacán, Mexico
| | - Luis E Eguiarte-Fruns
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México Coyoacán, Mexico
| | - Gabriela Delgado-Sapién
- Laboratorio de Genómica Bacteriana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México Coyoacán, Mexico
| | | | - Jaime Gasca-Pineda
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México Coyoacán, Mexico
| | - Jennifer Learned
- School of Life Sciences, Arizona State University, Tempe AZ, USA
| | - James J Elser
- School of Life Sciences, Arizona State University, Tempe AZ, USA
| | - Gabriela Olmedo-Alvarez
- Laboratorio de Bacteriología Molecular, Departamento de Ingeniería Genética, CINVESTAV - Unidad Irapuato Irapuato, Mexico
| | - Valeria Souza
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México Coyoacán, Mexico
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Diversity and Inheritance of Intergenic Spacer Sequences of 45S Ribosomal DNA among Accessions of Brassica oleracea L. var. capitata. Int J Mol Sci 2015; 16:28783-99. [PMID: 26633391 PMCID: PMC4691072 DOI: 10.3390/ijms161226125] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 11/24/2022] Open
Abstract
Ribosomal DNA (rDNA) of plants is present in high copy number and shows variation between and within species in the length of the intergenic spacer (IGS). The 45S rDNA of flowering plants includes the 5.8S, 18S and 25S rDNA genes, the internal transcribed spacer (ITS1 and ITS2), and the intergenic spacer 45S-IGS (25S-18S). This study identified six different types of 45S-IGS, A to F, which at 363 bp, 1121 bp, 1717 bp, 1969 bp, 2036 bp and 2111 bp in length, respectively, were much shorter than the reported reference IGS sequences in B. oleracea var. alboglabra. The shortest two IGS types, A and B, lacked the transcription initiation site, non-transcribed spacer, and external transcribed spacer. Functional behavior of those two IGS types in relation to rRNA synthesis is a subject of further investigation. The other four IGSs had subtle variations in the transcription termination site, guanine-cytosine (GC) content, and number of tandem repeats, but the external transcribed spacers of these four IGSs were quite similar in length. The 45S IGSs were found to follow Mendelian inheritance in a population of 15 F1s and their 30 inbred parental lines, which suggests that these sequences could be useful for development of new breeding tools. In addition, this study represents the first report of intra-specific (within subspecies) variation of the 45S IGS in B. oleracea.
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