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Translational repression by a miniature inverted-repeat transposable element in the 3' untranslated region. Nat Commun 2017; 8:14651. [PMID: 28256530 PMCID: PMC5338036 DOI: 10.1038/ncomms14651] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/18/2017] [Indexed: 12/18/2022] Open
Abstract
Transposable elements constitute a substantial portion of eukaryotic genomes and contribute to genomic variation, function, and evolution. Miniature inverted-repeat transposable elements (MITEs), as DNA transposons, are widely distributed in plant and animal genomes. Previous studies have suggested that retrotransposons act as translational regulators; however, it remains unknown how host mRNAs are influenced by DNA transposons. Here we report a translational repression mechanism mediated by a stowaway-like MITE (sMITE) embedded in the 3'-untranslated region (3'-UTR) of Ghd2, a member of the CCT (CONSTANS [CO], CO-LIKE and TIMING OF CAB1) gene family in rice. Ghd2 regulates important agronomic traits, including grain number, plant height and heading date. Interestingly, the translational repression of Ghd2 by the sMITE mainly relies on Dicer-like 3a (OsDCL3a). Furthermore, other MITEs in the 3'-UTRs of different rice genes exhibit a similar effect on translational repression, thus suggesting that MITEs may exert a general regulatory function at the translational level.
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252
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Patterns of Evolutionary Trajectories and Domestication History within the Genus Hordeum Assessed by REMAP Markers. J Mol Evol 2017; 84:116-128. [PMID: 28168328 DOI: 10.1007/s00239-016-9779-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 12/29/2016] [Indexed: 10/20/2022]
Abstract
The patterns of genetic diversity related to the taxonomy and domestication history of 85 accessions representing the main four species of the genus Hordeum were examined by retrotransposon-microsatellite amplified polymorphism (REMAP) markers based on the retrotransposon BARE-1. A substantial level of genetic polymorphisms at among- and within-species level was observed showing that this retrotransposon family and its adjacent genomic regions has been a target for genome dynamics during the evolution and domestication of barley. The obtained data are consistent with the current taxonomic status within the genus Hordeum. Similar level of genetic diversity was observed between the wild and the domesticated barley accessions suggesting that transposable elements` activity and accumulation may counteract the decrease of genome-wide diversity following domestication. In addition, eco-geographical sub-genome pools of the cultivated barley were identified in support to the theory of multiple origins of domestication within the genus Hordeum. We also provide conclusions about the relationship between accessions of different species and the putative routes of barley domestication. In conclusion, the retrotransposon BARE-1 stands as a reliable and perspective DNA marker for the assessment of the phylogenetic and domestication history in the genus Hordeum and other crop species.
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253
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Chen J, Wrightsman TR, Wessler SR, Stajich JE. RelocaTE2: a high resolution transposable element insertion site mapping tool for population resequencing. PeerJ 2017; 5:e2942. [PMID: 28149701 PMCID: PMC5274521 DOI: 10.7717/peerj.2942] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/26/2016] [Indexed: 12/26/2022] Open
Abstract
Background Transposable element (TE) polymorphisms are important components of population genetic variation. The functional impacts of TEs in gene regulation and generating genetic diversity have been observed in multiple species, but the frequency and magnitude of TE variation is under appreciated. Inexpensive and deep sequencing technology has made it affordable to apply population genetic methods to whole genomes with methods that identify single nucleotide and insertion/deletion polymorphisms. However, identifying TE polymorphisms, particularly transposition events or non-reference insertion sites can be challenging due to the repetitive nature of these sequences, which hamper both the sensitivity and specificity of analysis tools. Methods We have developed the tool RelocaTE2 for identification of TE insertion sites at high sensitivity and specificity. RelocaTE2 searches for known TE sequences in whole genome sequencing reads from second generation sequencing platforms such as Illumina. These sequence reads are used as seeds to pinpoint chromosome locations where TEs have transposed. RelocaTE2 detects target site duplication (TSD) of TE insertions allowing it to report TE polymorphism loci with single base pair precision. Results and Discussion The performance of RelocaTE2 is evaluated using both simulated and real sequence data. RelocaTE2 demonstrate high level of sensitivity and specificity, particularly when the sequence coverage is not shallow. In comparison to other tools tested, RelocaTE2 achieves the best balance between sensitivity and specificity. In particular, RelocaTE2 performs best in prediction of TSDs for TE insertions. Even in highly repetitive regions, such as those tested on rice chromosome 4, RelocaTE2 is able to report up to 95% of simulated TE insertions with less than 0.1% false positive rate using 10-fold genome coverage resequencing data. RelocaTE2 provides a robust solution to identify TE insertion sites and can be incorporated into analysis workflows in support of describing the complete genotype from light coverage genome sequencing.
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Affiliation(s)
- Jinfeng Chen
- Department of Plant Pathology & Microbiology, University of California, Riverside, CA, United States; Institute for Integrative Genome Biology, University of California, Riverside, CA, United States; Department of Botany and Plant Sciences, University of California, Riverside, CA, United States
| | - Travis R Wrightsman
- Department of Botany and Plant Sciences, University of California , Riverside , CA , United States
| | - Susan R Wessler
- Institute for Integrative Genome Biology, University of California, Riverside, CA, United States; Department of Botany and Plant Sciences, University of California, Riverside, CA, United States
| | - Jason E Stajich
- Department of Plant Pathology & Microbiology, University of California, Riverside, CA, United States; Institute for Integrative Genome Biology, University of California, Riverside, CA, United States
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254
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Li X, Guo K, Zhu X, Chen P, Li Y, Xie G, Wang L, Wang Y, Persson S, Peng L. Domestication of rice has reduced the occurrence of transposable elements within gene coding regions. BMC Genomics 2017; 18:55. [PMID: 28068923 PMCID: PMC5223533 DOI: 10.1186/s12864-016-3454-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/22/2016] [Indexed: 11/19/2022] Open
Abstract
Background Transposable elements (TEs) are prominent features in many plant genomes, and patterns of TEs in closely related rice species are thus proposed as an ideal model to study TEs roles in the context of plant genome evolution. As TEs may contribute to improved rice growth and grain quality, it is of pivotal significance for worldwide food security and biomass production. Results We analyzed three cultivated rice species and their closest five wild relatives for distribution and content of TEs in their genomes. Despite that the three cultivar rice species contained similar copies and more total TEs, their genomes contained much longer TEs as compared to their wild relatives. Notably, TEs were largely depleted from genomic regions that corresponded to genes in the cultivated species, while this was not the case for their wild relatives. Gene ontology and gene homology analyses revealed that while certain genes contained TEs in all the wild species, the closest homologs in the cultivated species were devoid of them. This distribution of TEs is surprising as the cultivated species are more distantly related to each other as compared to their closest wild relative. Hence, cultivated rice species have more similar TE distributions among their genes as compared to their closest wild relatives. We, furthermore, exemplify how genes that are conferring important rice traits can be regulated by TE associations. Conclusions This study demonstrate that the cultivation of rice has led to distinct genomic distribution of TEs, and that certain rice traits are closely associated with TE distribution patterns. Hence, the results provide means to better understand TE-dependent rice traits and the potential to genetically engineer rice for better performance. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3454-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xukai Li
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Kai Guo
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Xiaobo Zhu
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Peng Chen
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Ying Li
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Guosheng Xie
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Lingqiang Wang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Yanting Wang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Staffan Persson
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China. .,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China. .,School of Biosciences, University of Melbourne, Melbourne, VIC, 3010, Australia.
| | - Liangcai Peng
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China. .,National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China. .,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.
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255
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Stetter MG, Schmid KJ. Analysis of phylogenetic relationships and genome size evolution of the Amaranthus genus using GBS indicates the ancestors of an ancient crop. Mol Phylogenet Evol 2017; 109:80-92. [PMID: 28057554 DOI: 10.1016/j.ympev.2016.12.029] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 12/22/2016] [Accepted: 12/25/2016] [Indexed: 11/19/2022]
Abstract
The genus Amaranthus consists of 50-70 species and harbors several cultivated and weedy species of great economic importance. A small number of suitable traits, phenotypic plasticity, gene flow and hybridization made it difficult to establish the taxonomy and phylogeny of the whole genus despite various studies using molecular markers. We inferred the phylogeny of the Amaranthus genus using genotyping by sequencing (GBS) of 94 genebank accessions representing 35 Amaranthus species and measured their genome sizes. SNPs were called by de novo and reference-based methods, for which we used the distant sugarbeet Beta vulgaris and the closely related Amaranthus hypochondriacus as references. SNP counts and proportions of missing data differed between methods, but the resulting phylogenetic trees were highly similar. A distance-based neighbor joining tree of individual accessions and a species tree calculated with the multispecies coalescent supported a previous taxonomic classification into three subgenera although the subgenus A. Acnida consists of two highly differentiated clades. The analysis of the Hybridus complex within the A. Amaranthus subgenus revealed insights on the history of cultivated grain amaranths. The complex includes the three cultivated grain amaranths and their wild relatives and was well separated from other species in the subgenus. Wild and cultivated amaranth accessions did not differentiate according to the species assignment but clustered by their geographic origin from South and Central America. Different geographically separated populations of Amaranthus hybridus appear to be the common ancestors of the three cultivated grain species and A. quitensis might be additionally be involved in the evolution of South American grain amaranth (A. caudatus). We also measured genome sizes of the species and observed little variation with the exception of two lineages that showed evidence for a recent polyploidization. With the exception of two lineages, genome sizes are quite similar and indicate that polyploidization did not play a major role in the history of the genus.
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Affiliation(s)
- Markus G Stetter
- Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Fruwirthstr. 21, 70599 Stuttgart, Germany
| | - Karl J Schmid
- Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Fruwirthstr. 21, 70599 Stuttgart, Germany.
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256
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Abstract
Despite major progress in dissecting the molecular pathways that control DNA methylation patterns in plants, little is known about the mechanisms that shape plant methylomes over evolutionary time. Drawing on recent intra- and interspecific epigenomic studies, we show that methylome evolution over long timescales is largely a byproduct of genomic changes. By contrast, methylome evolution over short timescales appears to be driven mainly by spontaneous epimutational events. We argue that novel methods based on analyses of the methylation site frequency spectrum (mSFS) of natural populations can provide deeper insights into the evolutionary forces that act at each timescale.
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Affiliation(s)
- Amaryllis Vidalis
- Population Epigenetics and Epigenomics, Technical University of Munich, Liesel-Beckman-Str. 2, 85354, Freising, Germany
| | - Daniel Živković
- Population Genetics, Technical University of Munich, Liesel-Beckman-Str. 2, 85354, Freising, Germany
| | - René Wardenaar
- Groningen Bioinformatics Centre, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - David Roquis
- Population Epigenetics and Epigenomics, Technical University of Munich, Liesel-Beckman-Str. 2, 85354, Freising, Germany
| | - Aurélien Tellier
- Population Genetics, Technical University of Munich, Liesel-Beckman-Str. 2, 85354, Freising, Germany.
| | - Frank Johannes
- Population Epigenetics and Epigenomics, Technical University of Munich, Liesel-Beckman-Str. 2, 85354, Freising, Germany. .,Institute for Advanced Study, Technical University of Munich, Lichtenbergstr. 2a, 85748, Garching, Germany.
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257
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258
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Johnson ET, Owens JB, Moisyadi S. Vast potential for using the piggyBac transposon to engineer transgenic plants at specific genomic locations. Bioengineered 2016; 7:3-6. [PMID: 26930269 DOI: 10.1080/21655979.2015.1131367] [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: 12/21/2022] Open
Abstract
The acceptance of bioengineered plants by some nations is hampered by a number of factors, including the random insertion of a transgene into the host genome. Emerging technologies, such as site-specific nucleases, are enabling plant scientists to promote recombination or mutations at specific plant loci. Off target activity of these nucleases may limit widespread use. Insertion of transgenes by transposases engineered with a specific DNA binding domain has been accomplished in a number of organisms, but not in plants. The piggyBac transposon system, originally isolated from an insect, has been utilized to transform a variety of organisms. The piggyBac transposase is amendable to structural modifications, and was able to insert a transgene at a specific human locus through fusion of a DNA binding domain to its N-terminus. Recent developments demonstrating the activity of piggyBac transposase in plants is an important first step toward the potential use of engineered versions of piggyBac transposase for site-specific transgene insertion in plants.
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Affiliation(s)
- Eric T Johnson
- a Crop Bioprotection Research, USDA ARS , Peoria , Illinois
| | - Jesse B Owens
- b Institute for Biogenesis Research, University of Hawaii at Manoa , Honolulu , Hawaii
| | - Stefan Moisyadi
- b Institute for Biogenesis Research, University of Hawaii at Manoa , Honolulu , Hawaii
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259
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Xiong W, Dooner HK, Du C. Rolling-circle amplification of centromeric Helitrons in plant genomes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:1038-1045. [PMID: 27553634 DOI: 10.1111/tpj.13314] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 06/06/2023]
Abstract
The unusual eukaryotic Helitron transposons can readily capture host sequences and are, thus, evolutionarily important. They are presumed to amplify by rolling-circle replication (RCR) because some elements encode predicted proteins homologous to RCR prokaryotic transposases. In support of this replication mechanism, it was recently shown that transposition of a bat Helitron generates covalently closed circular intermediates. Another strong prediction is that RCR should generate tandem Helitron concatemers, yet almost all Helitrons identified to date occur as solo elements in the genome. To investigate alternative modes of Helitron organization in present-day genomes, we have applied the novel computational tool HelitronScanner to 27 plant genomes and have uncovered numerous tandem arrays of partially decayed, truncated Helitrons in all of them. Strikingly, most of these Helitron tandem arrays are interspersed with other repeats in centromeres. Many of these arrays have multiple Helitron 5' ends, but a single 3' end. The number of repeats in any one array can range from a handful to several hundreds. We propose here an RCR model that conforms to the present Helitron landscape of plant genomes. Our study provides strong evidence that plant Helitrons amplify by RCR and that the tandemly arrayed replication products accumulate mostly in centromeres.
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Affiliation(s)
- Wenwei Xiong
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Hugo K Dooner
- Waksman Institute, Rutgers, the State University of New Jersey, Piscataway, NJ, 08854, USA
- Department of Plant Biology, Rutgers, the State University of New Jersey, New Brunswick, NJ, 08801, USA
| | - Chunguang Du
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
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260
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Lwin AK, Bertolini E, Pè ME, Zuccolo A. Genomic skimming for identification of medium/highly abundant transposable elements in Arundo donax and Arundo plinii. Mol Genet Genomics 2016; 292:157-171. [PMID: 27778102 DOI: 10.1007/s00438-016-1263-3] [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] [Received: 08/08/2016] [Accepted: 10/17/2016] [Indexed: 11/29/2022]
Abstract
Transposable elements (TEs) are the most abundant genetic material for almost all eukaryotic genomes. Their effects on the host genomes range from an extensive size variation to the regulation of gene expression, altering gene function and creating new genes. Because of TEs pivotal contribute to the host genome structure and regulation, their identification and characterization provide a wealth of useful data for gaining an in-depth understanding of host genome functioning. The giant reed (Arundo donax) is a perennial rhizomatous C3 grass, octadecaploid, with an estimated nuclear genome size of 2744 Mbp. It is a promising feedstock for second-generation biofuels and biomethane production. To identify and characterize the most repetitive TEs in the genomes of A. donax and its ancestral A. plinii species, we carried out low-coverage whole genome shotgun sequencing for both species. Using a de novo repeat identification approach, 33,041 and 28,237 non-redundant repetitive sequences were identified and characterized in A. donax and A. plinii genomes, representing 37.55 and 31.68% of each genome, respectively. Comparative phylogenetic analyses, including the major TE classes identified in A. donax and A. plinii, together with rice and maize TE paralogs, were carried out to understand the evolutionary relationship of the most abundant TE classes. Highly conserved copies of RIRE1-like Ty1-Copia elements were discovered in two Arundo spp. in which they represented nearly 3% of each genomic sequence. We identified and characterized the medium/highly repetitive TEs in two unexplored polyploid genomes, thus generating useful information for the study of the genomic structure, composition, and functioning of these two non-model species. We provided a valuable resource that could be exploited in any effort aimed at sequencing and assembling these two genomes.
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Affiliation(s)
- Aung Kyaw Lwin
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, Italy.,Sugarcane Research and Seed Farm, Pyinmana, Nay Pyi Taw, Myanmar
| | - Edoardo Bertolini
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, Italy
| | - Mario Enrico Pè
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, Italy
| | - Andrea Zuccolo
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, Italy.
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261
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Rocha DM, Marques A, Andrade CGTJ, Guyot R, Chaluvadi SR, Pedrosa-Harand A, Houben A, Bennetzen JL, Vanzela ALL. Developmental programmed cell death during asymmetric microsporogenesis in holocentric species of Rhynchospora (Cyperaceae). JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:5391-5401. [PMID: 27492982 PMCID: PMC5049389 DOI: 10.1093/jxb/erw300] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Members of the Cyperaceae family exhibit an asymmetric microsporogenesis that results in the degeneration of three out of four meiotic products. Efforts have been made previously to describe the resulting structure, named the pseudomonad, but mechanisms concerning the establishment of cell domains, nuclear development, and programmed cell death are largely unknown. Using the Rhynchospora genus as a model, evidence for cell asymmetry, cytoplasmic isolation, and programmed cell death was obtained by a combination of electron microscopic, cytochemical, immunocytochemical, in situ hybridization, and flow cytometric methods. Degenerative cells were identified at the abaxial region, with the cytoskeleton marking their delimitation from the functional domain after meiosis. After attempting to initiate cell division with an unreplicated genome and abnormal spindle assembly, these cells exhibited a gradual process of cytoplasmic contraction associated with hypermethylation of cytosines and differential loss of DNA. These results indicate that the asymmetric tetrad establishes a functional cell, where one nucleus is preferentially selected to survive. Degenerative haploid cells are then eliminated in a multistep process associated with mitotic disorder, non-random elimination of repetitive DNA, vacuolar cell death, and DNA fragmentation.
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Affiliation(s)
- Danilo M Rocha
- Laboratory of Cytogenetics and Plant Diversity, Department of General Biology, Center of Biological Sciences, State University of Londrina, Londrina 86057-970, Paraná, Brazil
| | - André Marques
- Laboratory of Plant Cytogenetics and Evolution, Department of Botany, Federal University of Pernambuco, Recife, Brazil
| | - Celia G T J Andrade
- Laboratory of Electron Microscopy and Microanalysis, Pro-PPG, State University of Londrina, 86051990, Londrina, Brazil
| | - Romain Guyot
- Institut de Recherche pour le Développement (IRD), UMR IPME, BP 64501, 34394, Montpellier Cedex, France
| | | | - Andrea Pedrosa-Harand
- Laboratory of Plant Cytogenetics and Evolution, Department of Botany, Federal University of Pernambuco, Recife, Brazil
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466 Stadt Seeland, Germany
| | | | - André L L Vanzela
- Laboratory of Cytogenetics and Plant Diversity, Department of General Biology, Center of Biological Sciences, State University of Londrina, Londrina 86057-970, Paraná, Brazil
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262
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Characterization of new transposable element sub-families from white clover (Trifolium repens) using PCR amplification. Genetica 2016; 144:577-589. [PMID: 27671023 DOI: 10.1007/s10709-016-9926-x] [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] [Received: 04/25/2016] [Accepted: 09/17/2016] [Indexed: 12/15/2022]
Abstract
Transposable elements (TEs) dominate the landscapes of most plant and animal genomes. Once considered junk DNA and genetic parasites, these interspersed, repetitive DNA elements are now known to play major roles in both genetic and epigenetic processes that sponsor genome variation and regulate gene expression. Knowledge of TE consensus sequences from elements in species whose genomes have not been sequenced is limited, and the individual TEs that are encountered in clones or short-reads rarely represent potentially canonical, let alone, functional representatives. In this study, we queried the Repbase database with eight BAC clones from white clover (Trifolium repens), identified a large number of candidate TEs, and used polymerase chain reaction and Sanger sequencing to create consensus sequences for three new TE families. The results show that TE family consensus sequences can be obtained experimentally in species for which just a single, full-length member of a TE family has been sequenced.
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263
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Meštrović N, Mravinac B, Pavlek M, Vojvoda-Zeljko T, Šatović E, Plohl M. Structural and functional liaisons between transposable elements and satellite DNAs. Chromosome Res 2016; 23:583-96. [PMID: 26293606 DOI: 10.1007/s10577-015-9483-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transposable elements (TEs) and satellite DNAs (satDNAs) are typically identified as major repetitive DNA components in eukaryotic genomes. TEs are DNA segments able to move throughout a genome while satDNAs are tandemly repeated sequences organized in long arrays. Both classes of repetitive sequences are extremely diverse, and many TEs and satDNAs exist within a genome. Although they differ in structure, genomic organization, mechanisms of spread, and evolutionary dynamics, TEs and satDNAs can share sequence similarity and organizational patterns, thus indicating that complex mutual relationships can determine their evolution, and ultimately define roles they might have on genome architecture and function. Motivated by accumulating data about sequence elements that incorporate features of both TEs and satDNAs, here we present an overview of their structural and functional liaisons.
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Affiliation(s)
| | | | - Martina Pavlek
- Ruđer Bošković Institute, Bijenička 54, HR-10000, Zagreb, Croatia
| | | | - Eva Šatović
- Ruđer Bošković Institute, Bijenička 54, HR-10000, Zagreb, Croatia
| | - Miroslav Plohl
- Ruđer Bošković Institute, Bijenička 54, HR-10000, Zagreb, Croatia.
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264
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Santos FC, Guyot R, do Valle CB, Chiari L, Techio VH, Heslop-Harrison P, Vanzela ALL. Chromosomal distribution and evolution of abundant retrotransposons in plants: gypsy elements in diploid and polyploid Brachiaria forage grasses. Chromosome Res 2016; 23:571-82. [PMID: 26386563 DOI: 10.1007/s10577-015-9492-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Like other eukaryotes, the nuclear genome of plants consists of DNA with a small proportion of low-copy DNA (genes and regulatory sequences) and very abundant DNA sequence motifs that are repeated thousands up to millions of times in the genomes including transposable elements (TEs) and satellite DNA. Retrotransposons, one class of TEs, are sequences that amplify via an RNA intermediate and reinsert into the genome, are often the major fraction of a genome. Here, we put research on retrotransposons into the larger context of plant repetitive DNA and genome behaviour, showing features of genome evolution in a grass genus, Brachiaria, in relation to other plant species. We show the contrasting amplification of different retroelement fractions across the genome with characteristics for various families and domains. The genus Brachiaria includes both diploid and polyploid species, with similar chromosome types and chromosome basic numbers x = 6, 7, 8 and 9. The polyploids reproduce asexually and are apomictic, but there are also sexual species. Cytogenetic studies and flow cytometry indicate a large variation in DNA content (C-value), chromosome sizes and genome organization. In order to evaluate the role of transposable elements in the genome and karyotype organization of species of Brachiaria, we searched for sequences similar to conserved regions of TEs in RNAseq reads library produced in Brachiaria decumbens. Of the 9649 TE-like contigs, 4454 corresponded to LTR-retrotransposons, and of these, 79.5 % were similar to members of the gypsy superfamily. Sequences of conserved protein domains of gypsy were used to design primers for producing the probes. The probes were used in FISH against chromosomes of accesses of B. decumbens, Brachiaria brizantha, Brachiaria ruziziensis and Brachiaria humidicola. Probes showed hybridization signals predominantly in proximal regions, especially those for retrotransposons of the clades CRM and Athila, while elements of Del and Tat exhibited dispersed signals, in addition to those proximal signals. These results show that the proximal region of Brachiaria chromosomes is a hotspot for retrotransposon insertion, particularly for the gypsy family. The combination of high-throughput sequencing and a chromosome-centric cytogenetic approach allows the abundance, organization and nature of transposable elements to be characterized in unprecedented detail. By their amplification and dispersal, retrotransposons can affect gene expression; they can lead to rapid diversification of chromosomes between species and, hence, are useful for studies of genome evolution and speciation in the Brachiaria genus. Centromeric regions can be identified and mapped, and retrotransposon markers can also assisting breeders in the developing and exploiting interspecific hybrids.
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Affiliation(s)
- Fabíola Carvalho Santos
- Department of General Biology, Center of Biological Sciences, State University of Londrina, Londrina, 86057-970, Paraná State, Brazil
| | - Romain Guyot
- Institut de Recherche pour le Développement (IRD), UMR IPME, BP 64501, 34394, Montpellier Cedex, France
| | | | - Lucimara Chiari
- Embrapa Gado de Corte, 79106-550, Campo Grande, Mato Grosso do Sul State, Brazil
| | - Vânia Helena Techio
- Department of Biology, Federal University of Lavras, 37200-000, Lavras, Minas Gerais State, Brazil
| | | | - André Luís Laforga Vanzela
- Department of General Biology, Center of Biological Sciences, State University of Londrina, Londrina, 86057-970, Paraná State, Brazil.
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265
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Niederhuth CE, Schmitz RJ. Putting DNA methylation in context: from genomes to gene expression in plants. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:149-156. [PMID: 27590871 DOI: 10.1016/j.bbagrm.2016.08.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 08/20/2016] [Accepted: 08/23/2016] [Indexed: 12/26/2022]
Abstract
Plant DNA methylation is its own language, interpreted by the cell to maintain silencing of transposons, facilitate chromatin structure, and to ensure proper expression of some genes. Just as in any language, context is important. Rather than being a simple "on-off switch", DNA methylation has a range of "meanings" dependent upon the underlying sequence and its location in the genome. Differences in the sequence context of individual sites are established, maintained, and interpreted by differing molecular pathways. Varying patterns of methylation within genes and surrounding sequences are associated with a continuous range of expression differences, from silencing to constitutive expression. These often-subtle differences have been pieced together from years of effort, but have taken off with the advent of methods for assessing methylation across entire genomes. Recognizing these patterns and identifying underlying causes is essential for understanding the function of DNA methylation and its systems-wide contribution to a range of processes in plant genomes. This article is part of a Special Issue entitled: Plant Gene Regulatory Mechanisms and Networks, edited by Dr. Erich Grotewold and Dr. Nathan Springer.
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Affiliation(s)
- Chad E Niederhuth
- Department of Genetics, The University of Georgia, Athens, GA, 30602, USA
| | - Robert J Schmitz
- Department of Genetics, The University of Georgia, Athens, GA, 30602, USA.
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266
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Pinosio S, Giacomello S, Faivre-Rampant P, Taylor G, Jorge V, Le Paslier MC, Zaina G, Bastien C, Cattonaro F, Marroni F, Morgante M. Characterization of the Poplar Pan-Genome by Genome-Wide Identification of Structural Variation. Mol Biol Evol 2016; 33:2706-19. [PMID: 27499133 PMCID: PMC5026262 DOI: 10.1093/molbev/msw161] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Many recent studies have emphasized the important role of structural variation (SV) in determining human genetic and phenotypic variation. In plants, studies aimed at elucidating the extent of SV are still in their infancy. Evidence has indicated a high presence and an active role of SV in driving plant genome evolution in different plant species. With the aim of characterizing the size and the composition of the poplar pan-genome, we performed a genome-wide analysis of structural variation in three intercrossable poplar species: Populus nigra, Populus deltoides, and Populus trichocarpa. We detected a total of 7,889 deletions and 10,586 insertions relative to the P. trichocarpa reference genome, covering respectively 33.2 Mb and 62.9 Mb of genomic sequence, and 3,230 genes affected by copy number variation (CNV). The majority of the detected variants are inter-specific in agreement with a recent origin following separation of species. Insertions and deletions (INDELs) were preferentially located in low-gene density regions of the poplar genome and were, for the majority, associated with the activity of transposable elements. Genes affected by SV showed lower-than-average expression levels and higher levels of dN/dS, suggesting that they are subject to relaxed selective pressure or correspond to pseudogenes. Functional annotation of genes affected by INDELs showed over-representation of categories associated with transposable elements activity, while genes affected by genic CNVs showed enrichment in categories related to resistance to stress and pathogens. This study provides a genome-wide catalogue of SV and the first insight on functional and structural properties of the poplar pan-genome.
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Affiliation(s)
- Sara Pinosio
- Istituto di Bioscienze e Biorisorse, Consiglio Nazionale delle Ricerche, Sesto Fiorentino, Firenze, Italy Istituto di Genomica Applicata (IGA), Udine, Italy
| | - Stefania Giacomello
- Istituto di Genomica Applicata (IGA), Udine, Italy Dipartimento di Scienze Agro-alimentari, Università di Udine, Ambientali e Animali (DI4A), Udine, Italy
| | | | - Gail Taylor
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Veronique Jorge
- INRA, UR 0588 AGPF, Centre INRA Val de Loire, Orléans, France
| | | | - Giusi Zaina
- Dipartimento di Scienze Agro-alimentari, Università di Udine, Ambientali e Animali (DI4A), Udine, Italy
| | | | | | - Fabio Marroni
- Istituto di Genomica Applicata (IGA), Udine, Italy Dipartimento di Scienze Agro-alimentari, Università di Udine, Ambientali e Animali (DI4A), Udine, Italy
| | - Michele Morgante
- Istituto di Genomica Applicata (IGA), Udine, Italy Dipartimento di Scienze Agro-alimentari, Università di Udine, Ambientali e Animali (DI4A), Udine, Italy
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267
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Deleris A, Halter T, Navarro L. DNA Methylation and Demethylation in Plant Immunity. ANNUAL REVIEW OF PHYTOPATHOLOGY 2016; 54:579-603. [PMID: 27491436 DOI: 10.1146/annurev-phyto-080615-100308] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Detection of plant and animal pathogens triggers a massive transcriptional reprogramming, which is directed by chromatin-based processes, and ultimately results in antimicrobial immunity. Although the implication of histone modifications in orchestrating biotic stress-induced transcriptional reprogramming has been well characterized, very little was known, until recently, about the role of DNA methylation and demethylation in this process. In this review, we summarize recent findings on the dynamics and biological relevance of DNA methylation and demethylation in plant immunity against nonviral pathogens. In particular, we report the implications of these epigenetic regulatory processes in the transcriptional and co-transcriptional control of immune-responsive genes and discuss their relevance in fine-tuning antimicrobial immune responses. Finally, we discuss the possible yet elusive role of DNA methylation and demethylation in systemic immune responses, transgenerational immune priming, and de novo epiallelism, which could be adaptive.
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Affiliation(s)
- A Deleris
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8197, Institut National de la Santé et de la Recherche Médicale, Unité 1024, PSL Research University, 75005 Paris, France;
| | - T Halter
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8197, Institut National de la Santé et de la Recherche Médicale, Unité 1024, PSL Research University, 75005 Paris, France;
| | - L Navarro
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8197, Institut National de la Santé et de la Recherche Médicale, Unité 1024, PSL Research University, 75005 Paris, France;
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268
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Huang Y, Chen SY, Deng F. Well-characterized sequence features of eukaryote genomes and implications for ab initio gene prediction. Comput Struct Biotechnol J 2016; 14:298-303. [PMID: 27536341 PMCID: PMC4975701 DOI: 10.1016/j.csbj.2016.07.002] [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] [Received: 04/23/2016] [Revised: 07/06/2016] [Accepted: 07/12/2016] [Indexed: 12/31/2022] Open
Abstract
In silico analysis of DNA sequences is an important area of computational biology in the post-genomic era. Over the past two decades, computational approaches for ab initio prediction of gene structure from genome sequence alone have largely facilitated our understanding on a variety of biological questions. Although the computational prediction of protein-coding genes has already been well-established, we are also facing challenges to robustly find the non-coding RNA genes, such as miRNA and lncRNA. Two main aspects of ab initio gene prediction include the computed values for describing sequence features and used algorithm for training the discriminant function, and by which different combinations are employed into various bioinformatic tools. Herein, we briefly review these well-characterized sequence features in eukaryote genomes and applications to ab initio gene prediction. The main purpose of this article is to provide an overview to beginners who aim to develop the related bioinformatic tools.
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Affiliation(s)
- Ying Huang
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Shi-Yi Chen
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
- Corresponding author at: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, 211# Huimin Road, Wenjiang 611130, Sichuan, China.Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan ProvinceSichuan Agricultural University211# Huimin RoadWenjiangSichuan611130China
| | - Feilong Deng
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
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269
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Sun T, Renner SS, Xu Y, Qin Y, Wu J, Sun G. Two hAT transposon genes were transferred from Brassicaceae to broomrapes and are actively expressed in some recipients. Sci Rep 2016; 6:30192. [PMID: 27452947 PMCID: PMC4958966 DOI: 10.1038/srep30192] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/30/2016] [Indexed: 11/23/2022] Open
Abstract
A growing body of evidence is pointing to an important role of horizontal gene transfer (HGT) in the evolution of higher plants. However, reports of HGTs of transposable elements (TEs) in plants are still scarce, and only one case is known of a class II transposon horizontally transferred between grasses. To investigate possible TE transfers in dicots, we performed transcriptome screening in the obligate root parasite Phelipanche aegyptiaca (Orobanchaceae), data-mining in the draft genome assemblies of four other Orobanchaceae, gene cloning, gene annotation in species with genomic information, and a molecular phylogenetic analysis. We discovered that the broomrape genera Phelipanche and Orobanche acquired two related nuclear genes (christened BO transposase genes), a new group of the hAT superfamily of class II transposons, from Asian Sisymbrieae or a closely related tribe of Brassicaceae, by HGT. The collinearity of the flanking genes, lack of a classic border structure, and low expression levels suggest that BO transposase genes cannot transpose in Brassicaceae, whereas they are highly expressed in P. aegyptiaca.
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Affiliation(s)
- Ting Sun
- Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, Kaifeng 475004, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Susanne S. Renner
- Systematic Botany and Mycology, University of Munich (LMU), Munich 80638, Germany
| | - Yuxing Xu
- Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Yan Qin
- Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Jianqiang Wu
- Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Guiling Sun
- Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, Kaifeng 475004, China
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
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270
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Quadrana L, Bortolini Silveira A, Mayhew GF, LeBlanc C, Martienssen RA, Jeddeloh JA, Colot V. The Arabidopsis thaliana mobilome and its impact at the species level. eLife 2016; 5. [PMID: 27258693 PMCID: PMC4917339 DOI: 10.7554/elife.15716] [Citation(s) in RCA: 197] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/01/2016] [Indexed: 01/07/2023] Open
Abstract
Transposable elements (TEs) are powerful motors of genome evolution yet a comprehensive assessment of recent transposition activity at the species level is lacking for most organisms. Here, using genome sequencing data for 211 Arabidopsis thaliana accessions taken from across the globe, we identify thousands of recent transposition events involving half of the 326 TE families annotated in this plant species. We further show that the composition and activity of the 'mobilome' vary extensively between accessions in relation to climate and genetic factors. Moreover, TEs insert equally throughout the genome and are rapidly purged by natural selection from gene-rich regions because they frequently affect genes, in multiple ways. Remarkably, loci controlling adaptive responses to the environment are the most frequent transposition targets observed. These findings demonstrate the pervasive, species-wide impact that a rich mobilome can have and the importance of transposition as a recurrent generator of large-effect alleles.
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Affiliation(s)
- Leandro Quadrana
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Ecole Normale Supérieure, Paris, France
| | - Amanda Bortolini Silveira
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Ecole Normale Supérieure, Paris, France
| | | | - Chantal LeBlanc
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States
| | - Robert A Martienssen
- Watson School of Biological Sciences, Howard Hughes Medical Institute, Gordon and Betty Moore Foundation, Palo Alto, United States.,Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | | | - Vincent Colot
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Ecole Normale Supérieure, Paris, France
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271
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Huang K, Li CF, Wu J, Wei JH, Zou Y, Han MJ, Zhou ZY. Enhancer activity of Helitron in sericin-1 gene promoter from Bombyx mori. INSECT SCIENCE 2016; 23:396-405. [PMID: 27067405 DOI: 10.1111/1744-7917.12347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/30/2016] [Indexed: 06/05/2023]
Abstract
Sericin is a kind of water-soluble protein expressed specifically in the middle silk gland of Bombyx mori. When the sericin-1 gene promoter was cloned and a transgenic vector was constructed to express a foreign protein, a specific Helitron, Bmhel-8, was identified in the sericin-1 gene promoter sequence in some genotypes of Bombyx mori and Bombyx mandarina. Given that the Bmhel-8 Helitron transposon was present only in some genotypes, it could be the source of allelic variation in the sericin-1 promoter. The length of the sericin-1 promoter sequence is approximately 1063 or 643 bp. The larger size of the sequence or allele is ascribed to the presence of Bmhel-8. Silkworm genotypes can be homozygous for either the shorter or larger promoter sequence or heterozygous, containing both alleles. Bmhel-8 in the sericin-1 promoter exhibits enhancer activity, as demonstrated by a dual-luciferase reporter system in BmE cell lines. Furthermore, Bmhel-8 displays enhancer activity in a sericin-1 promoter-driven gene expression system but does not regulate the tissue-specific expression of sericin-1.
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Affiliation(s)
- Ke Huang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- College of Forestry & Life Science, Chongqing University of Arts & Sciences, Yongchuan, China
| | - Chun-Feng Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Jie Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Jun-Hong Wei
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Yong Zou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- College of Forestry & Life Science, Chongqing University of Arts & Sciences, Yongchuan, China
| | - Min-Jin Han
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Ze-Yang Zhou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Laboratory of Animal Biology, Chongqing Normal University, Chongqing, China
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272
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Li SF, Zhang GJ, Zhang XJ, Yuan JH, Deng CL, Gu LF, Gao WJ. DPTEdb, an integrative database of transposable elements in dioecious plants. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2016; 2016:baw078. [PMID: 27173524 PMCID: PMC4865326 DOI: 10.1093/database/baw078] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 04/22/2016] [Indexed: 02/02/2023]
Abstract
Dioecious plants usually harbor ‘young’ sex chromosomes, providing an opportunity to study the early stages of sex chromosome evolution. Transposable elements (TEs) are mobile DNA elements frequently found in plants and are suggested to play important roles in plant sex chromosome evolution. The genomes of several dioecious plants have been sequenced, offering an opportunity to annotate and mine the TE data. However, comprehensive and unified annotation of TEs in these dioecious plants is still lacking. In this study, we constructed a dioecious plant transposable element database (DPTEdb). DPTEdb is a specific, comprehensive and unified relational database and web interface. We used a combination of de novo, structure-based and homology-based approaches to identify TEs from the genome assemblies of previously published data, as well as our own. The database currently integrates eight dioecious plant species and a total of 31 340 TEs along with classification information. DPTEdb provides user-friendly web interfaces to browse, search and download the TE sequences in the database. Users can also use tools, including BLAST, GetORF, HMMER, Cut sequence and JBrowse, to analyze TE data. Given the role of TEs in plant sex chromosome evolution, the database will contribute to the investigation of TEs in structural, functional and evolutionary dynamics of the genome of dioecious plants. In addition, the database will supplement the research of sex diversification and sex chromosome evolution of dioecious plants. Database URL: http://genedenovoweb.ticp.net:81/DPTEdb/index.php
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Affiliation(s)
- Shu-Fen Li
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Guo-Jun Zhang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China
| | - Xue-Jin Zhang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Jin-Hong Yuan
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Chuan-Liang Deng
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Lian-Feng Gu
- Basic Forestry and Proteomics Center, Haixia Institute of Science and Technology (HIST), Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wu-Jun Gao
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
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273
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Taudt A, Colomé-Tatché M, Johannes F. Genetic sources of population epigenomic variation. Nat Rev Genet 2016; 17:319-32. [DOI: 10.1038/nrg.2016.45] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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274
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Wang L, Peng Q, Zhao J, Ren F, Zhou H, Wang W, Liao L, Owiti A, Jiang Q, Han Y. Evolutionary origin of Rosaceae-specific active non-autonomous hAT elements and their contribution to gene regulation and genomic structural variation. PLANT MOLECULAR BIOLOGY 2016; 91:179-91. [PMID: 26941188 DOI: 10.1007/s11103-016-0454-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/08/2016] [Indexed: 06/05/2023]
Abstract
Transposable elements account for approximately 30 % of the Prunus genome; however, their evolutionary origin and functionality remain largely unclear. In this study, we identified a hAT transposon family, termed Moshan, in Prunus. The Moshan elements consist of three types, aMoshan, tMoshan, and mMoshan. The aMoshan and tMoshan types contain intact or truncated transposase genes, respectively, while the mMoshan type is miniature inverted-repeat transposable element (MITE). The Moshan transposons are unique to Rosaceae, and the copy numbers of different Moshan types are significantly correlated. Sequence homology analysis reveals that the mMoshan MITEs are direct deletion derivatives of the tMoshan progenitors, and one kind of mMoshan containing a MuDR-derived fragment were amplified predominately in the peach genome. The mMoshan sequences contain cis-regulatory elements that can enhance gene expression up to 100-fold. The mMoshan MITEs can serve as potential sources of micro and long noncoding RNAs. Whole-genome re-sequencing analysis indicates that mMoshan elements are highly active, and an insertion into S-haplotype-specific F-box gene was reported to cause the breakdown of self-incompatibility in sour cherry. Taken together, all these results suggest that the mMoshan elements play important roles in regulating gene expression and driving genomic structural variation in Prunus.
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Affiliation(s)
- Lu Wang
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China
| | - Qian Peng
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China
- Graduate University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing, 100049, People's Republic of China
| | - Jianbo Zhao
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, A12, Ruiwangfen, Beijing, 100093, People's Republic of China
| | - Fei Ren
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, A12, Ruiwangfen, Beijing, 100093, People's Republic of China
| | - Hui Zhou
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China
- Graduate University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing, 100049, People's Republic of China
| | - Wei Wang
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China
| | - Liao Liao
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China
- Sino-African Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China
| | - Albert Owiti
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China
- Graduate University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing, 100049, People's Republic of China
| | - Quan Jiang
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, A12, Ruiwangfen, Beijing, 100093, People's Republic of China.
| | - Yuepeng Han
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China.
- Sino-African Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China.
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275
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Abstract
Although individuals in most flowering plant species, and in many haploid plants, have both sex functions, dioecious species-in which individuals have either male or female functions only-are scattered across many taxonomic groups, and many species have genetic sex determination. Among these, some have visibly heteromorphic sex chromosomes, and molecular genetic studies are starting to uncover sex-linked markers in others, showing that they too have fully sex-linked regions that are either too small or are located in chromosomes that are too small to be cytologically detectable from lack of pairing, lack of visible crossovers, or accumulation of heterochromatin. Detailed study is revealing that, like animal sex chromosomes, plant sex-linked regions show evidence for accumulation of repetitive sequences and genetic degeneration. Estimating when recombination stopped confirms the view that many plants have young sex-linked regions, making plants of great interest for studying the timescale of these changes.
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Affiliation(s)
- Deborah Charlesworth
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom;
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276
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Abstract
The Mutator system of transposable elements (TEs) is a highly mutagenic family of transposons in maize. Because they transpose at high rates and target genic regions, these transposons can rapidly generate large numbers of new mutants, which has made the Mutator system a favored tool for both forward and reverse mutagenesis in maize. Low copy number versions of this system have also proved to be excellent models for understanding the regulation and behavior of Class II transposons in plants. Notably, the availability of a naturally occurring locus that can heritably silence autonomous Mutator elements has provided insights into the means by which otherwise active transposons are recognized and silenced. This chapter will provide a review of the biology, regulation, evolution and uses of this remarkable transposon system, with an emphasis on recent developments in our understanding of the ways in which this TE system is recognized and epigenetically silenced as well as recent evidence that Mu-like elements (MULEs) have had a significant impact on the evolution of plant genomes.
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277
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Zhang Z, Ham BK, Lucas WJ. Systemic silencing: Mobile sRNA stabilizes genomes. NATURE PLANTS 2016; 2:16020. [PMID: 27249354 DOI: 10.1038/nplants.2016.20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Zhaoliang Zhang
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, California 95616, USA
| | - Byung-Kook Ham
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, California 95616, USA
| | - William J Lucas
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, California 95616, USA
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278
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Abstract
We have witnessed an explosion in our understanding of the evolution and structure of plant genomes in recent years. Here, we highlight three important emergent realizations: (1) that the evolutionary history of all plant genomes contains multiple, cyclical episodes of whole-genome doubling that were followed by myriad fractionation processes; (2) that the vast majority of the variation in genome size reflects the dynamics of proliferation and loss of lineage-specific transposable elements; and (3) that various classes of small RNAs help shape genomic architecture and function. We illustrate ways in which understanding these organism-level and molecular genetic processes can be used for crop plant improvement.
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Affiliation(s)
- Jonathan F Wendel
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.
| | - Scott A Jackson
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA, 30602, USA
| | - Blake C Meyers
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO, 63132, USA.,Division of Plant Sciences, University of Missouri-Columbia, 52 Agriculture Laboratory, Columbia, MO, 65211, USA
| | - Rod A Wing
- Arizona Genomics Institute, School of Plant Sciences and Department of Ecology and Evolutionary Biology, Tucson, AZ, 85750, USA.,T.T. Chang Genetic Resource Center, International Rice Research Institute, Los Baños, Laguna, Philippines
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279
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R. Lorenzetti AP, A. de Antonio GY, Paschoal AR, Domingues DS. PlanTE-MIR DB: a database for transposable element-related microRNAs in plant genomes. Funct Integr Genomics 2016; 16:235-42. [DOI: 10.1007/s10142-016-0480-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 10/22/2022]
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280
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Schwichtenberg K, Wenke T, Zakrzewski F, Seibt KM, Minoche A, Dohm JC, Weisshaar B, Himmelbauer H, Schmidt T. Diversification, evolution and methylation of short interspersed nuclear element families in sugar beet and related Amaranthaceae species. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:229-44. [PMID: 26676716 DOI: 10.1111/tpj.13103] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/23/2015] [Accepted: 11/26/2015] [Indexed: 05/18/2023]
Abstract
Short interspersed nuclear elements (SINEs) are non-autonomous non-long terminal repeat retrotransposons which are widely distributed in eukaryotic organisms. While SINEs have been intensively studied in animals, only limited information is available about plant SINEs. We analysed 22 SINE families from seven genomes of the Amaranthaceae family and identified 34 806 SINEs, including 19 549 full-length copies. With the focus on sugar beet (Beta vulgaris), we performed a comparative analysis of the diversity, genomic and chromosomal organization and the methylation of SINEs to provide a detailed insight into the evolution and age of Amaranthaceae SINEs. The lengths of consensus sequences of SINEs range from 113 nucleotides (nt) up to 224 nt. The SINEs show dispersed distribution on all chromosomes but were found with higher incidence in subterminal euchromatic chromosome regions. The methylation of SINEs is increased compared with their flanking regions, and the strongest effect is visible for cytosines in the CHH context, indicating an involvement of asymmetric methylation in the silencing of SINEs.
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Affiliation(s)
| | - Torsten Wenke
- Institute of Botany, Technische Universität Dresden, 01069, Dresden, Germany
| | - Falk Zakrzewski
- Institute of Botany, Technische Universität Dresden, 01069, Dresden, Germany
| | - Kathrin M Seibt
- Institute of Botany, Technische Universität Dresden, 01069, Dresden, Germany
| | - André Minoche
- Max Planck Institute for Molecular Genetics, 14195, Berlin, Germany
- Garvan Institute of Medical Research, 2010, Sydney, NSW, Australia
| | - Juliane C Dohm
- Max Planck Institute for Molecular Genetics, 14195, Berlin, Germany
- Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), 1190, Vienna, Austria
| | - Bernd Weisshaar
- CeBiTec & Department of Biology, University of Bielefeld, 33615, Bielefeld, Germany
| | - Heinz Himmelbauer
- Garvan Institute of Medical Research, 2010, Sydney, NSW, Australia
- Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), 1190, Vienna, Austria
| | - Thomas Schmidt
- Institute of Botany, Technische Universität Dresden, 01069, Dresden, Germany
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281
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Traller JC, Cokus SJ, Lopez DA, Gaidarenko O, Smith SR, McCrow JP, Gallaher SD, Podell S, Thompson M, Cook O, Morselli M, Jaroszewicz A, Allen EE, Allen AE, Merchant SS, Pellegrini M, Hildebrand M. Genome and methylome of the oleaginous diatom Cyclotella cryptica reveal genetic flexibility toward a high lipid phenotype. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:258. [PMID: 27933100 PMCID: PMC5124317 DOI: 10.1186/s13068-016-0670-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 11/15/2016] [Indexed: 05/08/2023]
Abstract
BACKGROUND Improvement in the performance of eukaryotic microalgae for biofuel and bioproduct production is largely dependent on characterization of metabolic mechanisms within the cell. The marine diatom Cyclotella cryptica, which was originally identified in the Aquatic Species Program, is a promising strain of microalgae for large-scale production of biofuel and bioproducts, such as omega-3 fatty acids. RESULTS We sequenced the nuclear genome and methylome of this oleaginous diatom to identify the genetic traits that enable substantial accumulation of triacylglycerol. The genome is comprised of highly methylated repetitive sequence, which does not significantly change under silicon starved lipid induction, and data further suggests the primary role of DNA methylation is to suppress DNA transposition. Annotation of pivotal glycolytic, lipid metabolism, and carbohydrate degradation processes reveal an expanded enzyme repertoire in C. cryptica that would allow for an increased metabolic capacity toward triacylglycerol production. Identification of previously unidentified genes, including those involved in carbon transport and chitin metabolism, provide potential targets for genetic manipulation of carbon flux to further increase its lipid phenotype. New genetic tools were developed, bringing this organism on a par with other microalgae in terms of genetic manipulation and characterization approaches. CONCLUSIONS Functional annotation and detailed cross-species comparison of key carbon rich processes in C. cryptica highlights the importance of enzymatic subcellular compartmentation for regulation of carbon flux, which is often overlooked in photosynthetic microeukaryotes. The availability of the genome sequence, as well as advanced genetic manipulation tools enable further development of this organism for deployment in large-scale production systems.
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Affiliation(s)
- Jesse C. Traller
- Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
| | - Shawn J. Cokus
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095 USA
| | - David A. Lopez
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095 USA
| | - Olga Gaidarenko
- Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
| | - Sarah R. Smith
- Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037 USA
| | - John P. McCrow
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037 USA
| | - Sean D. Gallaher
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095 USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095 USA
| | - Sheila Podell
- Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
| | - Michael Thompson
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095 USA
| | - Orna Cook
- Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
| | - Marco Morselli
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095 USA
| | - Artur Jaroszewicz
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095 USA
| | - Eric E. Allen
- Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
| | - Andrew E. Allen
- Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037 USA
| | - Sabeeha S. Merchant
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095 USA
| | - Matteo Pellegrini
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095 USA
| | - Mark Hildebrand
- Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202 USA
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282
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Šurbanovski N, Brilli M, Moser M, Si-Ammour A. A highly specific microRNA-mediated mechanism silences LTR retrotransposons of strawberry. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:70-82. [PMID: 26611654 DOI: 10.1111/tpj.13090] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/06/2015] [Accepted: 11/20/2015] [Indexed: 06/05/2023]
Abstract
Small RNAs are involved in a plethora of functions in plant genomes. In general, transcriptional gene silencing is mediated by 24-nucleotide siRNAs and is required for maintaining transposable elements in a silenced state. However, microRNAs are not commonly associated with transposon silencing. In this study, we performed small RNA transcriptome and degradome analyses of the Rosaceae model plant Fragaria vesca (the woodland strawberry) at the genome-wide level, and identified miRNA families and their targets. We report a highly specific mechanism of LTR retrotransposon silencing mediated by an abundant, ubiquitously expressed miRNA (fve-miR1511) generated from a single locus. This miRNA specifically targets LTR retroelements, silencing them post-transcriptionally by perfectly pairing to the highly conserved primer binding site for methionyl initiator tRNA that is essential for reverse transcription. We investigated the possible origins of this miRNA, and present evidence that the pre-miR1511 hairpin structure probably derived from a locus coding for tRNA(iM) (et) through a single microinversion event. Our study shows that this miRNA targets retrotransposons specifically and constitutively, and contributes to features such as genome stability, size and architecture in a far more direct way than previously thought.
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Affiliation(s)
- Nada Šurbanovski
- Functional Genomics, Department of Genomics and Biology of Fruit Crops, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, San Michele all' Adige, 38010, Italy
| | - Matteo Brilli
- Functional Genomics, Department of Genomics and Biology of Fruit Crops, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, San Michele all' Adige, 38010, Italy
| | - Mirko Moser
- Functional Genomics, Department of Genomics and Biology of Fruit Crops, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, San Michele all' Adige, 38010, Italy
| | - Azeddine Si-Ammour
- Functional Genomics, Department of Genomics and Biology of Fruit Crops, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, San Michele all' Adige, 38010, Italy
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283
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Wang K, Huang G, Zhu Y. Transposable elements play an important role during cotton genome evolution and fiber cell development. SCIENCE CHINA-LIFE SCIENCES 2015; 59:112-21. [PMID: 26687725 DOI: 10.1007/s11427-015-4928-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/20/2015] [Indexed: 11/26/2022]
Abstract
Transposable elements (TEs) usually occupy largest fractions of plant genome and are also the most variable part of the structure. Although traditionally it is hallmarked as "junk and selfish DNA", today more and more evidence points out TE's participation in gene regulations including gene mutation, duplication, movement and novel gene creation via genetic and epigenetic mechanisms. The recently sequenced genomes of diploid cottons Gossypium arboreum (AA) and Gossypium raimondii (DD) together with their allotetraploid progeny Gossypium hirsutum (AtAtDtDt) provides a unique opportunity to compare genome variations in the Gossypium genus and to analyze the functions of TEs during its evolution. TEs accounted for 57%, 68.5% and 67.2%, respectively in DD, AA and AtAtDtDt genomes. The 1,694 Mb A-genome was found to harbor more LTR(long terminal repeat)-type retrotransposons that made cardinal contributions to the twofold increase in its genome size after evolution from the 775.2 Mb D-genome. Although the 2,173 Mb AtAtDtDt genome showed similar TE content to the A-genome, the total numbers of LTR-gypsy and LTR-copia type TEs varied significantly between these two genomes. Considering their roles on rewiring gene regulatory networks, we believe that TEs may somehow be involved in cotton fiber cell development. Indeed, the insertion or deletion of different TEs in the upstream region of two important transcription factor genes in At or Dt subgenomes resulted in qualitative differences in target gene expression. We suggest that our findings may open a window for improving cotton agronomic traits by editing TE activities.
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Affiliation(s)
- Kun Wang
- College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Gai Huang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Yuxian Zhu
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.
- Institute for Advanced Studies, Wuhan University, Wuhan, 430072, China.
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284
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Reverse transcriptase genes are highly abundant and transcriptionally active in marine plankton assemblages. ISME JOURNAL 2015; 10:1134-46. [PMID: 26613339 PMCID: PMC5029228 DOI: 10.1038/ismej.2015.192] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 08/27/2015] [Accepted: 09/22/2015] [Indexed: 11/18/2022]
Abstract
Genes encoding reverse transcriptases (RTs) are found in most eukaryotes, often
as a component of retrotransposons, as well as in retroviruses and in
prokaryotic retroelements. We investigated the abundance, classification and
transcriptional status of RTs based on Tara Oceans marine metagenomes
and metatranscriptomes encompassing a wide organism size range. Our analyses
revealed that RTs predominate large-size fraction metagenomes
(>5 μm), where they reached a maximum of 13.5% of the total
gene abundance. Metagenomic RTs were widely distributed across the phylogeny of
known RTs, but many belonged to previously uncharacterized clades.
Metatranscriptomic RTs showed distinct abundance patterns across samples
compared with metagenomic RTs. The relative abundances of viral and bacterial
RTs among identified RT sequences were higher in metatranscriptomes than in
metagenomes and these sequences were detected in all metatranscriptome size
fractions. Overall, these observations suggest an active proliferation of
various RT-assisted elements, which could be involved in genome evolution or
adaptive processes of plankton assemblage.
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285
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Macas J, Novák P, Pellicer J, Čížková J, Koblížková A, Neumann P, Fuková I, Doležel J, Kelly LJ, Leitch IJ. In Depth Characterization of Repetitive DNA in 23 Plant Genomes Reveals Sources of Genome Size Variation in the Legume Tribe Fabeae. PLoS One 2015; 10:e0143424. [PMID: 26606051 PMCID: PMC4659654 DOI: 10.1371/journal.pone.0143424] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/04/2015] [Indexed: 01/30/2023] Open
Abstract
The differential accumulation and elimination of repetitive DNA are key drivers of genome size variation in flowering plants, yet there have been few studies which have analysed how different types of repeats in related species contribute to genome size evolution within a phylogenetic context. This question is addressed here by conducting large-scale comparative analysis of repeats in 23 species from four genera of the monophyletic legume tribe Fabeae, representing a 7.6-fold variation in genome size. Phylogenetic analysis and genome size reconstruction revealed that this diversity arose from genome size expansions and contractions in different lineages during the evolution of Fabeae. Employing a combination of low-pass genome sequencing with novel bioinformatic approaches resulted in identification and quantification of repeats making up 55–83% of the investigated genomes. In turn, this enabled an analysis of how each major repeat type contributed to the genome size variation encountered. Differential accumulation of repetitive DNA was found to account for 85% of the genome size differences between the species, and most (57%) of this variation was found to be driven by a single lineage of Ty3/gypsy LTR-retrotransposons, the Ogre elements. Although the amounts of several other lineages of LTR-retrotransposons and the total amount of satellite DNA were also positively correlated with genome size, their contributions to genome size variation were much smaller (up to 6%). Repeat analysis within a phylogenetic framework also revealed profound differences in the extent of sequence conservation between different repeat types across Fabeae. In addition to these findings, the study has provided a proof of concept for the approach combining recent developments in sequencing and bioinformatics to perform comparative analyses of repetitive DNAs in a large number of non-model species without the need to assemble their genomes.
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Affiliation(s)
- Jiří Macas
- Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, České Budějovice, Czech Republic
- * E-mail:
| | - Petr Novák
- Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, České Budějovice, Czech Republic
| | - Jaume Pellicer
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom
| | - Jana Čížková
- Institute of Experimental Botany, Olomouc, Centre of the Region Haná for Biotechnological and Agricultural Research, Olomouc, Czech Republic
| | - Andrea Koblížková
- Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, České Budějovice, Czech Republic
| | - Pavel Neumann
- Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, České Budějovice, Czech Republic
| | - Iva Fuková
- Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, České Budějovice, Czech Republic
| | - Jaroslav Doležel
- Institute of Experimental Botany, Olomouc, Centre of the Region Haná for Biotechnological and Agricultural Research, Olomouc, Czech Republic
| | - Laura J. Kelly
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Ilia J. Leitch
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom
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286
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Dodsworth S, Leitch AR, Leitch IJ. Genome size diversity in angiosperms and its influence on gene space. Curr Opin Genet Dev 2015; 35:73-8. [PMID: 26605684 DOI: 10.1016/j.gde.2015.10.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/28/2015] [Accepted: 10/28/2015] [Indexed: 01/02/2023]
Abstract
Genome size varies c. 2400-fold in angiosperms (flowering plants), although the range of genome size is skewed towards small genomes, with a mean genome size of 1C=5.7Gb. One of the most crucial factors governing genome size in angiosperms is the relative amount and activity of repetitive elements. Recently, there have been new insights into how these repeats, previously discarded as 'junk' DNA, can have a significant impact on gene space (i.e. the part of the genome comprising all the genes and gene-related DNA). Here we review these new findings and explore in what ways genome size itself plays a role in influencing how repeats impact genome dynamics and gene space, including gene expression.
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Affiliation(s)
- Steven Dodsworth
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Ilia J Leitch
- Department of Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK.
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287
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Senerchia N, Felber F, Parisod C. Genome reorganization in F1 hybrids uncovers the role of retrotransposons in reproductive isolation. Proc Biol Sci 2015; 282:20142874. [PMID: 25716787 DOI: 10.1098/rspb.2014.2874] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Interspecific hybridization leads to new interactions among divergent genomes, revealing the nature of genetic incompatibilities having accumulated during and after the origin of species. Conflicts associated with misregulation of transposable elements (TEs) in hybrids expectedly result in their activation and genome-wide changes that may be key to species boundaries. Repetitive genomes of wild wheats have diverged under differential dynamics of specific long terminal repeat retrotransposons (LTR-RTs), offering unparalleled opportunities to address the underpinnings of plant genome reorganization by selfish sequences. Using reciprocal F1 hybrids between three Aegilops species, restructuring and epigenetic repatterning was assessed at random and LTR-RT sequences with amplified fragment length polymorphism and sequence-specific amplified polymorphisms as well as their methylation-sensitive counterparts, respectively. Asymmetrical reorganization of LTR-RT families predicted to cause conflicting interactions matched differential survival of F1 hybrids. Consistent with the genome shock model, increasing divergence of merged LTR-RTs yielded higher levels of changes in corresponding genome fractions and lead to repeated reorganization of LTR-RT sequences in F1 hybrids. Such non-random reorganization of hybrid genomes is coherent with the necessary repression of incompatible TE loci in support of hybrid viability and indicates that TE-driven genomic conflicts may represent an overlooked factor supporting reproductive isolation.
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Affiliation(s)
- Natacha Senerchia
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, Neuchâtel 2000, Switzerland
| | - François Felber
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, Neuchâtel 2000, Switzerland Musée et Jardins Botaniques Cantonaux, Lausanne 1007, Switzerland
| | - Christian Parisod
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, Neuchâtel 2000, Switzerland
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288
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Kabelitz T, Bäurle I. Get the jump - Do 3'UTRs protect transposable elements from silencing? Mob Genet Elements 2015; 5:51-54. [PMID: 26442184 DOI: 10.1080/2159256x.2015.1052179] [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] [Received: 01/06/2015] [Revised: 04/29/2015] [Accepted: 05/08/2015] [Indexed: 12/26/2022] Open
Abstract
Eukaryotic genomes contain large numbers of transposable elements and repetitive sequences that are subjected to silencing through epigenetic mechanisms. These involve primarily DNA methylation, chromatin modifications and small RNA. It is known that these transposable elements can affect the expression of neighboring genes; however, little is known about how transposable element silencing depends on the general chromosomal environment at the insertion site. Taking advantage of the vast genomic resources available in Arabidopsis thaliana, a recent report begins to unravel these interactions by identifying insertion sites of one specific MULE element, AtMu1c across the A. thaliana lineage. Among over 30 insertion sites analyzed, a correlation between the loss of epigenetic silencing and the insertion into the 3'end of protein coding genes was found. Here, we discuss details, implications and potential mechanisms of these findings that may be applicable to a much wider set of transposable elements and across diverse species.
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Affiliation(s)
- Tina Kabelitz
- Institute for Biochemistry and Biology; University of Potsdam ; Potsdam, Germany
| | - Isabel Bäurle
- Institute for Biochemistry and Biology; University of Potsdam ; Potsdam, Germany
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289
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Klein BA, Chen T, Scott JC, Koenigsberg AL, Duncan MJ, Hu LT. Identification and characterization of a minisatellite contained within a novel miniature inverted-repeat transposable element (MITE) of Porphyromonas gingivalis. Mob DNA 2015; 6:18. [PMID: 26448788 PMCID: PMC4596501 DOI: 10.1186/s13100-015-0049-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/23/2015] [Indexed: 12/26/2022] Open
Abstract
Background Repetitive regions of DNA and transposable elements have been found to constitute large percentages of eukaryotic and prokaryotic genomes. Such elements are known to be involved in transcriptional regulation, host-pathogen interactions and genome evolution. Results We identified a minisatellite contained within a miniature inverted-repeat transposable element (MITE) in Porphyromonas gingivalis. The P. gingivalis minisatellite and associated MITE, named ‘BrickBuilt’, comprises a tandemly repeating twenty-three nucleotide DNA sequence lacking spacer regions between repeats, and with flanking ‘leader’ and ‘tail’ subunits that include small inverted-repeat ends. Forms of the BrickBuilt MITE are found 19 times in the genome of P. gingivalis strain ATCC 33277, and also multiple times within the strains W83, TDC60, HG66 and JCVI SC001. BrickBuilt is always located intergenically ranging between 49 and 591 nucleotides from the nearest upstream and downstream coding sequences. Segments of BrickBuilt contain promoter elements with bidirectional transcription capabilities. Conclusions We performed a bioinformatic analysis of BrickBuilt utilizing existing whole genome sequencing, microarray and RNAseq data, as well as performing in vitro promoter probe assays to determine potential roles, mechanisms and regulation of the expression of these elements and their affect on surrounding loci. The multiplicity, localization and limited host range nature of MITEs and MITE-like elements in P. gingivalis suggest that these elements may play an important role in facilitating genome evolution as well as modulating the transcriptional regulatory system. Electronic supplementary material The online version of this article (doi:10.1186/s13100-015-0049-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Brian A Klein
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Biomedical Sciences, Boston, MA 02111 USA ; Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 USA
| | - Tsute Chen
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 USA
| | - Jodie C Scott
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 USA
| | - Andrea L Koenigsberg
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Biomedical Sciences, Boston, MA 02111 USA
| | - Margaret J Duncan
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 USA
| | - Linden T Hu
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Biomedical Sciences, Boston, MA 02111 USA
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290
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Fultz D, Choudury SG, Slotkin RK. Silencing of active transposable elements in plants. CURRENT OPINION IN PLANT BIOLOGY 2015; 27:67-76. [PMID: 26164237 DOI: 10.1016/j.pbi.2015.05.027] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/20/2015] [Accepted: 05/22/2015] [Indexed: 05/04/2023]
Abstract
In plant genomes the vast majority of transposable elements (TEs) are found in a transcriptionally silenced state that is epigenetically propagated from generation to generation. Although the mechanism of this maintenance of silencing has been well studied, it is now clear that the pathways responsible for maintaining TEs in a silenced state differ from the pathways responsible for initially targeting the TE for silencing. Recently, attention in this field has focused on investigating the molecular mechanisms that initiate and establish TE silencing. Here we review the current models of how TEs are triggered for silencing, the data supporting each model, and the key future questions in this fast moving field.
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Affiliation(s)
- Dalen Fultz
- Department of Molecular Genetics, The Ohio State University, United States
| | - Sarah G Choudury
- Department of Molecular Genetics, The Ohio State University, United States
| | - R Keith Slotkin
- Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States.
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291
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Kelly LJ, Renny‐Byfield S, Pellicer J, Macas J, Novák P, Neumann P, Lysak MA, Day PD, Berger M, Fay MF, Nichols RA, Leitch AR, Leitch IJ. Analysis of the giant genomes of Fritillaria (Liliaceae) indicates that a lack of DNA removal characterizes extreme expansions in genome size. THE NEW PHYTOLOGIST 2015; 208:596-607. [PMID: 26061193 PMCID: PMC4744688 DOI: 10.1111/nph.13471] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 04/20/2015] [Indexed: 05/18/2023]
Abstract
Plants exhibit an extraordinary range of genome sizes, varying by > 2000-fold between the smallest and largest recorded values. In the absence of polyploidy, changes in the amount of repetitive DNA (transposable elements and tandem repeats) are primarily responsible for genome size differences between species. However, there is ongoing debate regarding the relative importance of amplification of repetitive DNA versus its deletion in governing genome size. Using data from 454 sequencing, we analysed the most repetitive fraction of some of the largest known genomes for diploid plant species, from members of Fritillaria. We revealed that genomic expansion has not resulted from the recent massive amplification of just a handful of repeat families, as shown in species with smaller genomes. Instead, the bulk of these immense genomes is composed of highly heterogeneous, relatively low-abundance repeat-derived DNA, supporting a scenario where amplified repeats continually accumulate due to infrequent DNA removal. Our results indicate that a lack of deletion and low turnover of repetitive DNA are major contributors to the evolution of extremely large genomes and show that their size cannot simply be accounted for by the activity of a small number of high-abundance repeat families.
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Affiliation(s)
- Laura J. Kelly
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonE1 4NSUK
- Jodrell LaboratoryRoyal Botanic GardensKewRichmondTW9 3DSUK
| | - Simon Renny‐Byfield
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonE1 4NSUK
- Department of Plant SciencesUniversity of California DavisDavisCA95616USA
| | - Jaume Pellicer
- Jodrell LaboratoryRoyal Botanic GardensKewRichmondTW9 3DSUK
| | - Jiří Macas
- Biology Centre CASInstitute of Plant Molecular BiologyCZ‐37005České BudějoviceCzech Republic
| | - Petr Novák
- Biology Centre CASInstitute of Plant Molecular BiologyCZ‐37005České BudějoviceCzech Republic
| | - Pavel Neumann
- Biology Centre CASInstitute of Plant Molecular BiologyCZ‐37005České BudějoviceCzech Republic
| | - Martin A. Lysak
- Plant Cytogenomics Research GroupCEITEC – Central European Institute of TechnologyMasaryk UniversityKamenice 5CZ‐62500BrnoCzech Republic
| | - Peter D. Day
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonE1 4NSUK
- Jodrell LaboratoryRoyal Botanic GardensKewRichmondTW9 3DSUK
| | - Madeleine Berger
- Jodrell LaboratoryRoyal Botanic GardensKewRichmondTW9 3DSUK
- School of Biological and Biomedical SciencesDurham UniversitySouth RoadDurhamDH1 3LEUK
- Rothamsted ResearchWest CommonHarpendenHertfordshireAL5 2JQUK
| | - Michael F. Fay
- Jodrell LaboratoryRoyal Botanic GardensKewRichmondTW9 3DSUK
| | - Richard A. Nichols
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonE1 4NSUK
| | - Andrew R. Leitch
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonE1 4NSUK
| | - Ilia J. Leitch
- Jodrell LaboratoryRoyal Botanic GardensKewRichmondTW9 3DSUK
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292
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Abstract
It is tempting to invoke organismal selection as perpetually optimizing the function of any given gene. However, natural selection can drive genic functional change without improvement of biochemical activity, even to the extinction of gene activity. Detrimental mutations can creep in owing to linkage with other selectively favored loci. Selection can promote functional degradation, irrespective of genetic drift, when adaptation occurs by loss of gene function. Even stabilizing selection on a trait can lead to divergence of the underlying molecular constituents. Selfish genetic elements can also proliferate independent of any functional benefits to the host genome. Here we review the logic and evidence for these diverse processes acting in genome evolution. This collection of distinct evolutionary phenomena - while operating through easily understandable mechanisms - all contribute to the seemingly counterintuitive notion that maintenance or improvement of a gene's biochemical function sometimes do not determine its evolutionary fate.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Richard Jovelin
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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293
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Hayashi-Tsugane M, Maekawa M, Tsugane K. A gain-of-function Bushy dwarf tiller 1 mutation in rice microRNA gene miR156d caused by insertion of the DNA transposon nDart1. Sci Rep 2015; 5:14357. [PMID: 26403301 PMCID: PMC4585910 DOI: 10.1038/srep14357] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/26/2015] [Indexed: 12/22/2022] Open
Abstract
A non-autonomous DNA transposon in rice, nDart1, is actively transposed in the presence of an autonomous element, aDart1, under natural conditions. The nDart1-promoted gene tagging line was developed using the endogenous nDart1/aDart1 system to generate various rice mutants effectively. While the dominant mutants were occasionally isolated from the tagging line, it was unclear what causes dominant mutations. A semidominant mutant, Bushy dwarf tiller1 (Bdt1), which has the valuable agronomic traits of multiple tillering and dwarfism, was obtained from the tagging line. Bdt1 mutant carried a newly inserted nDart1 at 38-bp upstream of transcription initiation site of a non-protein-coding gene, miR156d. This insertion caused an upstream shift of the miR156d transcription initiation site and, consequently, increased the functional transcripts producing mature microRNAs. These results indicate that the total amount of miR156d is controlled not only by transcript quantity but also by transcript quality. Furthermore, transgenic lines introduced an miR156d fragment that flanked the nDart1 sequence at the 5′ region, suggesting that insertion of nDart1 in the gene promoter region enhances gene expression as a cis-element. This study demonstrates the ability of nDart1 to produce gain-of-function mutants as well as further insights into the function of transposable elements in genome evolution.
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Affiliation(s)
| | - Masahiko Maekawa
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan
| | - Kazuo Tsugane
- National Institute for Basic Biology, Okazaki 444-8585, Japan.,The Graduate University for Advanced Studies [SOKENDAI], Okazaki 444-8585, Japan
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294
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Ma L, Hatlen A, Kelly LJ, Becher H, Wang W, Kovarik A, Leitch IJ, Leitch AR. Angiosperms Are Unique among Land Plant Lineages in the Occurrence of Key Genes in the RNA-Directed DNA Methylation (RdDM) Pathway. Genome Biol Evol 2015; 7:2648-62. [PMID: 26338185 PMCID: PMC4607528 DOI: 10.1093/gbe/evv171] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The RNA-directed DNA methylation (RdDM) pathway can be divided into three phases: 1) small interfering RNA biogenesis, 2) de novo methylation, and 3) chromatin modification. To determine the degree of conservation of this pathway we searched for key genes among land plants. We used OrthoMCL and the OrthoMCL Viridiplantae database to analyze proteomes of species in bryophytes, lycophytes, monilophytes, gymnosperms, and angiosperms. We also analyzed small RNA size categories and, in two gymnosperms, cytosine methylation in ribosomal DNA. Six proteins were restricted to angiosperms, these being NRPD4/NRPE4, RDM1, DMS3 (defective in meristem silencing 3), SHH1 (SAWADEE homeodomain homolog 1), KTF1, and SUVR2, although we failed to find the latter three proteins in Fritillaria persica, a species with a giant genome. Small RNAs of 24 nt in length were abundant only in angiosperms. Phylogenetic analyses of Dicer-like (DCL) proteins showed that DCL2 was restricted to seed plants, although it was absent in Gnetum gnemon and Welwitschia mirabilis. The data suggest that phases (1) and (2) of the RdDM pathway, described for model angiosperms, evolved with angiosperms. The absence of some features of RdDM in F. persica may be associated with its large genome. Phase (3) is probably the most conserved part of the pathway across land plants. DCL2, involved in virus defense and interaction with the canonical RdDM pathway to facilitate methylation of CHH, is absent outside seed plants. Its absence in G. gnemon, and W. mirabilis coupled with distinctive patterns of CHH methylation, suggest a secondary loss of DCL2 following the divergence of Gnetales.
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Affiliation(s)
- Lu Ma
- School of Biological and Chemical Sciences, Queen Mary University of London, United Kingdom
| | - Andrea Hatlen
- School of Biological and Chemical Sciences, Queen Mary University of London, United Kingdom
| | - Laura J Kelly
- School of Biological and Chemical Sciences, Queen Mary University of London, United Kingdom
| | - Hannes Becher
- School of Biological and Chemical Sciences, Queen Mary University of London, United Kingdom
| | - Wencai Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, United Kingdom
| | - Ales Kovarik
- Department of Molecular Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | - Ilia J Leitch
- Department of Comparative Plant and Fungal Biology Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary University of London, United Kingdom
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295
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Wang Y, Drader T, Tiwari VK, Dong L, Kumar A, Huo N, Ghavami F, Iqbal MJ, Lazo GR, Leonard J, Gill BS, Kianian SF, Luo MC, Gu YQ. Development of a D genome specific marker resource for diploid and hexaploid wheat. BMC Genomics 2015; 16:646. [PMID: 26315263 PMCID: PMC4552153 DOI: 10.1186/s12864-015-1852-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 08/17/2015] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Mapping and map-based cloning of genes that control agriculturally and economically important traits remain great challenges for plants with complex highly repetitive genomes such as those within the grass tribe, Triticeae. Mapping limitations in the Triticeae are primarily due to low frequencies of polymorphic gene markers and poor genetic recombination in certain genetic regions. Although the abundance of repetitive sequence may pose common problems in genome analysis and sequence assembly of large and complex genomes, they provide repeat junction markers with random and unbiased distribution throughout chromosomes. Hence, development of a high-throughput mapping technology that combine both gene-based and repeat junction-based markers is needed to generate maps that have better coverage of the entire genome. RESULTS In this study, the available genomics resource of the diploid Aegilop tauschii, the D genome donor of bread wheat, were used to develop genome specific markers that can be applied for mapping in modern hexaploid wheat. A NimbleGen array containing both gene-based and repeat junction probe sequences derived from Ae. tauschii was developed and used to map the Chinese Spring nullisomic-tetrasomic lines and deletion bin lines of the D genome chromosomes. Based on these mapping data, we have now anchored 5,171 repeat junction probes and 10,892 gene probes, corresponding to 5,070 gene markers, to the delineated deletion bins of the D genome. The order of the gene-based markers within the deletion bins of the Chinese Spring can be inferred based on their positions on the Ae. tauschii genetic map. Analysis of the probe sequences against the Chinese Spring chromosome sequence assembly database facilitated mapping of the NimbleGen probes to the sequence contigs and allowed assignment or ordering of these sequence contigs within the deletion bins. The accumulated length of anchored sequence contigs is about 155 Mb, representing ~ 3.2 % of the D genome. A specific database was developed to allow user to search or BLAST against the probe sequence information and to directly download PCR primers for mapping specific genetic loci. CONCLUSIONS In bread wheat, aneuploid stocks have been extensively used to assign markers linked with genes/traits to chromosomes, chromosome arms, and their specific bins. Through this study, we added thousands of markers to the existing wheat chromosome bin map, representing a significant step forward in providing a resource to navigate the wheat genome. The database website ( http://probes.pw.usda.gov/ATRJM/ ) provides easy access and efficient utilization of the data. The resources developed herein can aid map-based cloning of traits of interest and the sequencing of the D genome of hexaploid wheat.
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Affiliation(s)
- Yi Wang
- Western Regional Research Center, USDA-ARS, Albany, CA, 94710, USA. .,Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
| | - Thomas Drader
- Western Regional Research Center, USDA-ARS, Albany, CA, 94710, USA.
| | - Vijay K Tiwari
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR, 97331, USA. .,Wheat Genetic Resource Center, Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506, USA.
| | - Lingli Dong
- Western Regional Research Center, USDA-ARS, Albany, CA, 94710, USA. .,Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
| | - Ajay Kumar
- Department of Plant Sciences, North Dakota State University, Fargo, ND, 58108, USA. ajay.kumar.2.@ndsu.edu
| | - Naxin Huo
- Western Regional Research Center, USDA-ARS, Albany, CA, 94710, USA.,Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Farhad Ghavami
- Department of Plant Sciences, North Dakota State University, Fargo, ND, 58108, USA.,Molecular Breeding and Genomics Technology Laboratory, BioDiagnostics Inc., River Falls, WI, 54022, USA
| | - M Javed Iqbal
- Department of Plant Sciences, North Dakota State University, Fargo, ND, 58108, USA
| | - Gerard R Lazo
- Western Regional Research Center, USDA-ARS, Albany, CA, 94710, USA.
| | - Jeff Leonard
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR, 97331, USA.
| | - Bikram S Gill
- Wheat Genetic Resource Center, Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506, USA.
| | | | - Ming-Cheng Luo
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
| | - Yong Q Gu
- Western Regional Research Center, USDA-ARS, Albany, CA, 94710, USA.
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296
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Palomeque T, Sanllorente O, Maside X, Vela J, Mora P, Torres MI, Periquet G, Lorite P. Evolutionary history of the Azteca-like mariner transposons and their host ants. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2015. [PMID: 26195134 DOI: 10.1007/s00114-015-1294-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Three different complete mariner elements were found in the genome of the ant Tapinoma nigerrimum. One (Tnigmar-Mr) was interrupted by a 900-bp insertion that corresponded to an incomplete member of a fourth mariner element, called Azteca. In this work, we isolate and characterize full-length Tnigmar-Az elements in T. nigerrimum. The purpose of this study is to clarify the evolutionary history of Azteca elements and their hosts as well as the possible existence of horizontal transfer processes. For this, Azteca-like elements were also retrieved from the available sequences of various ant genomes, representing four different ant subfamilies: Dolichoderinae, Formicinae, Myrmicinae, and Ponerinae. The tree topology resulting for the Azteca-like elements bore very little resemblance to that of their respective hosts. The pervasive presence of Azteca-like elements in all ant genomes, together with the observation that extant copies are usually younger than the genomes that host them, could be explained either by lineage sorting or by recent horizontal transfer of active elements. However, the finding of closer genetic relationships between elements than between the ants that host them is consistent with the latter scenario. This is clearly observed in Sinvmar-Az, Tnigmar-Az, Acepmar-Az, and Cflomar-Az elements, suggesting the existence of horizontal transfer processes. On the contrary, some elements displayed more divergence than did the hosts harboring them. This may reflect either further horizontal transfer events or random lineage sorting.
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Affiliation(s)
- Teresa Palomeque
- Departamento de Biología Experimental, Universidad de Jaén, 23071, Jaén, Spain
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297
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Sun C, Feschotte C, Wu Z, Mueller RL. DNA transposons have colonized the genome of the giant virus Pandoravirus salinus. BMC Biol 2015; 13:38. [PMID: 26067596 PMCID: PMC4495683 DOI: 10.1186/s12915-015-0145-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/03/2015] [Indexed: 01/06/2023] Open
Abstract
Background Transposable elements are mobile DNA sequences that are widely distributed in prokaryotic and eukaryotic genomes, where they represent a major force in genome evolution. However, transposable elements have rarely been documented in viruses, and their contribution to viral genome evolution remains largely unexplored. Pandoraviruses are recently described DNA viruses with genome sizes that exceed those of some prokaryotes, rivaling parasitic eukaryotes. These large genomes appear to include substantial noncoding intergenic spaces, which provide potential locations for transposable element insertions. However, no mobile genetic elements have yet been reported in pandoravirus genomes. Results Here, we report a family of miniature inverted-repeat transposable elements (MITEs) in the Pandoravirus salinus genome, representing the first description of a virus populated with a canonical transposable element family that proliferated by transposition within the viral genome. The MITE family, which we name Submariner, includes 30 copies with all the hallmarks of MITEs: short length, terminal inverted repeats, TA target site duplication, and no coding capacity. Submariner elements show signs of transposition and are undetectable in the genome of Pandoravirus dulcis, the closest known relative Pandoravirus salinus. We identified a DNA transposon related to Submariner in the genome of Acanthamoeba castellanii, a species thought to host pandoraviruses, which contains remnants of coding sequence for a Tc1/mariner transposase. These observations suggest that the Submariner MITEs of P. salinus belong to the widespread Tc1/mariner superfamily and may have been mobilized by an amoebozoan host. Ten of the 30 MITEs in the P. salinus genome are located within coding regions of predicted genes, while others are close to genes, suggesting that these transposons may have contributed to viral genetic novelty. Conclusions Our discovery highlights the remarkable ability of DNA transposons to colonize and shape genomes from all domains of life, as well as giant viruses. Our findings continue to blur the division between viral and cellular genomes, adhering to the emerging view that the content, dynamics, and evolution of the genomes of giant viruses do not substantially differ from those of cellular organisms. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0145-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cheng Sun
- Department of Biology, Colorado State University, Campus Delivery 1878, Fort Collins, CO, 80523-1878, USA.
| | - Cédric Feschotte
- Department of Human Genetics, The University of Utah, Salt Lake City, UT, 84112, USA.
| | - Zhiqiang Wu
- Department of Biology, Colorado State University, Campus Delivery 1878, Fort Collins, CO, 80523-1878, USA.
| | - Rachel Lockridge Mueller
- Department of Biology, Colorado State University, Campus Delivery 1878, Fort Collins, CO, 80523-1878, USA.
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298
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Bergero R, Qiu S, Charlesworth D. Gene loss from a plant sex chromosome system. Curr Biol 2015; 25:1234-40. [PMID: 25913399 DOI: 10.1016/j.cub.2015.03.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 02/10/2015] [Accepted: 03/11/2015] [Indexed: 12/31/2022]
Abstract
Sex chromosomes have evolved independently in numerous animal and plant lineages. After recombination becomes suppressed between two homologous sex chromosomes, genes on the non-recombining Y chromosomes (and W chromosomes in ZW systems) undergo genetic degeneration, losing functions retained by their X- or Z-linked homologs, changing their expression, and becoming lost [1, 2]. Adaptive changes may also occur, both on the non-recombining Y chromosome, to shut down expression of maladapted genes [3], and on the X chromosome (or the Z in ZW systems), which may evolve dosage compensation to increase low expression or compensate for poor protein function in the heterogametic sex [2, 4, 5]. Although empirical approaches to studying genetic degeneration have been developed for model species [3, 6], the onset and dynamics of these changes are still poorly understood, particularly in de novo evolving sex chromosomes. Sex chromosomes of some plants evolved much more recently than those of mammals, birds, and Drosophila [7-9], making them suitable for studying the early stages of genetic degeneration in de novo evolving sex chromosomes. In plants, haploid selection should oppose gene loss from Y chromosomes, but recent work on sex chromosomes of two plant species has estimated that Y-linked transcripts are lacking for 10%-30% of X-linked genes [10-12]. Here, we provide evidence that, in Silene latifolia, this largely involved losses of Y-linked genes, and not suppressed expression of Y-linked alleles, or gene additions to the X chromosome. Our results also suggest that chromosome-wide dosage compensation does not occur in this plant.
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Affiliation(s)
- Roberta Bergero
- Institute of Evolutionary Biology, University of Edinburgh, EH9 3JT Edinburgh, UK.
| | - Suo Qiu
- Institute of Evolutionary Biology, University of Edinburgh, EH9 3JT Edinburgh, UK
| | - Deborah Charlesworth
- Institute of Evolutionary Biology, University of Edinburgh, EH9 3JT Edinburgh, UK
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299
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Li F, Fan G, Lu C, Xiao G, Zou C, Kohel RJ, Ma Z, Shang H, Ma X, Wu J, Liang X, Huang G, Percy RG, Liu K, Yang W, Chen W, Du X, Shi C, Yuan Y, Ye W, Liu X, Zhang X, Liu W, Wei H, Wei S, Huang G, Zhang X, Zhu S, Zhang H, Sun F, Wang X, Liang J, Wang J, He Q, Huang L, Wang J, Cui J, Song G, Wang K, Xu X, Yu JZ, Zhu Y, Yu S. Genome sequence of cultivated Upland cotton (Gossypium hirsutum TM-1) provides insights into genome evolution. Nat Biotechnol 2015; 33:524-30. [PMID: 25893780 DOI: 10.1038/nbt.3208] [Citation(s) in RCA: 661] [Impact Index Per Article: 73.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 03/15/2015] [Indexed: 12/27/2022]
Abstract
Gossypium hirsutum has proven difficult to sequence owing to its complex allotetraploid (AtDt) genome. Here we produce a draft genome using 181-fold paired-end sequences assisted by fivefold BAC-to-BAC sequences and a high-resolution genetic map. In our assembly 88.5% of the 2,173-Mb scaffolds, which cover 89.6%∼96.7% of the AtDt genome, are anchored and oriented to 26 pseudochromosomes. Comparison of this G. hirsutum AtDt genome with the already sequenced diploid Gossypium arboreum (AA) and Gossypium raimondii (DD) genomes revealed conserved gene order. Repeated sequences account for 67.2% of the AtDt genome, and transposable elements (TEs) originating from Dt seem more active than from At. Reduction in the AtDt genome size occurred after allopolyploidization. The A or At genome may have undergone positive selection for fiber traits. Concerted evolution of different regulatory mechanisms for Cellulose synthase (CesA) and 1-Aminocyclopropane-1-carboxylic acid oxidase1 and 3 (ACO1,3) may be important for enhanced fiber production in G. hirsutum.
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Affiliation(s)
- Fuguang Li
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | | | - Cairui Lu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Guanghui Xiao
- 1] State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China. [2] Institute for Advanced Studies and College of Life Sciences, Wuhan University, Wuhan, China
| | - Changsong Zou
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Russell J Kohel
- Crop Germplasm Research Unit, Southern Plains Agricultural Research Center, US Department of Agriculture-Agricultural Research Service (USDA-ARS), College Station, Texas, USA
| | - Zhiying Ma
- Key Laboratory for Crop Germplasm Resources of Hebei, Agricultural University of Hebei, Baoding, China
| | - Haihong Shang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Xiongfeng Ma
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Jianyong Wu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | | | - Gai Huang
- 1] State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China. [2] Institute for Advanced Studies and College of Life Sciences, Wuhan University, Wuhan, China
| | - Richard G Percy
- Crop Germplasm Research Unit, Southern Plains Agricultural Research Center, US Department of Agriculture-Agricultural Research Service (USDA-ARS), College Station, Texas, USA
| | - Kun Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Weihua Yang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | | | - Xiongming Du
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | | | - Youlu Yuan
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Wuwei Ye
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Xin Liu
- BGI-Shenzhen, Shenzhen, China
| | - Xueyan Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | | | - Hengling Wei
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Shoujun Wei
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | | | - Xianlong Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Shuijin Zhu
- Department of Agronomy, Zhejiang University, Hangzhou, China
| | | | | | - Xingfen Wang
- Key Laboratory for Crop Germplasm Resources of Hebei, Agricultural University of Hebei, Baoding, China
| | | | | | | | | | | | - Jinjie Cui
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Guoli Song
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Kunbo Wang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
| | - Xun Xu
- BGI-Shenzhen, Shenzhen, China
| | - John Z Yu
- Crop Germplasm Research Unit, Southern Plains Agricultural Research Center, US Department of Agriculture-Agricultural Research Service (USDA-ARS), College Station, Texas, USA
| | - Yuxian Zhu
- 1] State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China. [2] Institute for Advanced Studies and College of Life Sciences, Wuhan University, Wuhan, China
| | - Shuxun Yu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, China
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Dhadi SR, Xu Z, Shaik R, Driscoll K, Ramakrishna W. Differential regulation of genes by retrotransposons in rice promoters. PLANT MOLECULAR BIOLOGY 2015; 87:603-13. [PMID: 25697955 DOI: 10.1007/s11103-015-0300-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 02/16/2015] [Indexed: 05/06/2023]
Abstract
Rice genome harbors genes and promoters with retrotransposon insertions. There is very little information about their function. The effect of retrotransposon insertions in four rice promoter regions on gene regulation, was investigated using promoter-reporter gene constructs with and without retrotransposons. Differences in expression levels of gus and egfp reporter genes in forward orientation and rfp in reverse orientation were evaluated in rice plants with transient expression employing quantitative RT-PCR analysis, histochemical GUS staining, and eGFP and RFP fluorescent microscopy. The presence of SINE in the promoter 1 (P1) resulted in higher expression levels of the reporter genes, whereas the presence of LINE in P2 or gypsy LTR retrotransposon in P3 reduced expression of the reporter genes. Furthermore, the SINE in P1 acts as an enhancer in contrast with the LINE in P2 and the gypsy LTR retrotransposon in P3 which act as silencers. CTAA and CGG motifs in these retrotransposons are the likely candidates for the downregulation compared to TCTT motif (SINE) which is a candidate for the upregulation of gene expression. The effect of retrotransposons on gene regulation correlated with the earlier investigation of conservation patterns of these four retrotransposon insertions in several rice accessions implying their evolutionary significance.
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Affiliation(s)
- Surendar Reddy Dhadi
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, 49931, USA
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