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Hassan AH, Mokhtar MM, El Allali A. Transposable elements: multifunctional players in the plant genome. FRONTIERS IN PLANT SCIENCE 2024; 14:1330127. [PMID: 38239225 PMCID: PMC10794571 DOI: 10.3389/fpls.2023.1330127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024]
Abstract
Transposable elements (TEs) are indispensable components of eukaryotic genomes that play diverse roles in gene regulation, recombination, and environmental adaptation. Their ability to mobilize within the genome leads to gene expression and DNA structure changes. TEs serve as valuable markers for genetic and evolutionary studies and facilitate genetic mapping and phylogenetic analysis. They also provide insight into how organisms adapt to a changing environment by promoting gene rearrangements that lead to new gene combinations. These repetitive sequences significantly impact genome structure, function and evolution. This review takes a comprehensive look at TEs and their applications in biotechnology, particularly in the context of plant biology, where they are now considered "genomic gold" due to their extensive functionalities. The article addresses various aspects of TEs in plant development, including their structure, epigenetic regulation, evolutionary patterns, and their use in gene editing and plant molecular markers. The goal is to systematically understand TEs and shed light on their diverse roles in plant biology.
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Affiliation(s)
- Asmaa H. Hassan
- Bioinformatics Laboratory, College of Computing, Mohammed VI Polytechnic University, Ben Guerir, Morocco
- Agricultural Genetic Engineering Research Institute, Agriculture Research Center, Giza, Egypt
| | - Morad M. Mokhtar
- Bioinformatics Laboratory, College of Computing, Mohammed VI Polytechnic University, Ben Guerir, Morocco
- Agricultural Genetic Engineering Research Institute, Agriculture Research Center, Giza, Egypt
| | - Achraf El Allali
- Bioinformatics Laboratory, College of Computing, Mohammed VI Polytechnic University, Ben Guerir, Morocco
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2
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Ramakrishnan M, Papolu PK, Mullasseri S, Zhou M, Sharma A, Ahmad Z, Satheesh V, Kalendar R, Wei Q. The role of LTR retrotransposons in plant genetic engineering: how to control their transposition in the genome. PLANT CELL REPORTS 2023; 42:3-15. [PMID: 36401648 DOI: 10.1007/s00299-022-02945-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
We briefly discuss that the similarity of LTR retrotransposons to retroviruses is a great opportunity for the development of a genetic engineering tool that exploits intragenic elements in the plant genome for plant genetic improvement. Long terminal repeat (LTR) retrotransposons are very similar to retroviruses but do not have the property of being infectious. While spreading between its host cells, a retrovirus inserts a DNA copy of its genome into the cells. The ability of retroviruses to cause infection with genome integration allows genes to be delivered to cells and tissues. Retrovirus vectors are, however, only specific to animals and insects, and, thus, are not relevant to plant genetic engineering. However, the similarity of LTR retrotransposons to retroviruses is an opportunity to explore the former as a tool for genetic engineering. Although recent long-read sequencing technologies have advanced the knowledge about transposable elements (TEs), the integration of TEs is still unable either to control them or to direct them to specific genomic locations. The use of existing intragenic elements to achieve the desired genome composition is better than using artificial constructs like vectors, but it is not yet clear how to control the process. Moreover, most LTR retrotransposons are inactive and unable to produce complete proteins. They are also highly mutable. In addition, it is impossible to find a full active copy of a LTR retrotransposon out of thousands of its own copies. Theoretically, if these elements were directly controlled and turned on or off using certain epigenetic mechanisms (inducing by stress or infection), LTR retrotransposons could be a great opportunity to develop a genetic engineering tool using intragenic elements in the plant genome. In this review, the recent developments in uncovering the nature of LTR retrotransposons and the possibility of using these intragenic elements as a tool for plant genetic engineering are briefly discussed.
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Affiliation(s)
- Muthusamy Ramakrishnan
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Key Laboratory of National Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Pradeep K Papolu
- State Key Laboratory of Subtropical Silviculture, Institute of Bamboo Research, Zhejiang A&F University, Lin'an, Hangzhou, 311300, Zhejiang, China
| | - Sileesh Mullasseri
- Department of Zoology, St. Albert's College (Autonomous), Kochi, 682018, Kerala, India
| | - Mingbing Zhou
- State Key Laboratory of Subtropical Silviculture, Institute of Bamboo Research, Zhejiang A&F University, Lin'an, Hangzhou, 311300, Zhejiang, China
- Zhejiang Provincial Collaborative Innovation Center for Bamboo Resources and High-Efficiency Utilization, Zhejiang A&F University, Lin'an, Hangzhou, 311300, Zhejiang, China
| | - Anket Sharma
- State Key Laboratory of Subtropical Silviculture, Institute of Bamboo Research, Zhejiang A&F University, Lin'an, Hangzhou, 311300, Zhejiang, China
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, USA
| | - Zishan Ahmad
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Key Laboratory of National Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Viswanathan Satheesh
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Ruslan Kalendar
- Helsinki Institute of Life Science HiLIFE, University of Helsinki, Biocenter 3, Viikinkaari 1, F1-00014, Helsinki, Finland.
- Institute of Plant Biology and Biotechnology (IPBB), Timiryazev Street 45, 050040, Almaty, Kazakhstan.
| | - Qiang Wei
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Key Laboratory of National Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China.
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3
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Khapilina O, Turzhanova A, Danilova A, Tumenbayeva A, Shevtsov V, Kotukhov Y, Kalendar R. Primer Binding Site (PBS) Profiling of Genetic Diversity of Natural Populations of Endemic Species Allium ledebourianum Schult. BIOTECH 2021; 10:23. [PMID: 35822797 PMCID: PMC9245474 DOI: 10.3390/biotech10040023] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/25/2021] [Accepted: 10/11/2021] [Indexed: 11/20/2022] Open
Abstract
Endemic species are especially vulnerable to biodiversity loss caused by isolation or habitat specificity, small population size, and anthropogenic factors. Endemic species biodiversity analysis has a critically important global value for the development of conservation strategies. The rare onion Allium ledebourianum is a narrow-lined endemic species, with natural populations located in the extreme climatic conditions of the Kazakh Altai. A. ledebourianum populations are decreasing everywhere due to anthropogenic impact, and therefore, this species requires preservation and protection. Conservation of this rare species is associated with monitoring studies to investigate the genetic diversity of natural populations. Fundamental components of eukaryote genome include multiple classes of interspersed repeats. Various PCR-based DNA fingerprinting methods are used to detect chromosomal changes related to recombination processes of these interspersed elements. These methods are based on interspersed repeat sequences and are an effective approach for assessing the biological diversity of plants and their variability. We applied DNA profiling approaches based on conservative sequences of interspersed repeats to assess the genetic diversity of natural A. ledebourianum populations located in the territory of Kazakhstan Altai. The analysis of natural A. ledebourianum populations, carried out using the DNA profiling approach, allowed the effective differentiation of the populations and assessment of their genetic diversity. We used conservative sequences of tRNA primer binding sites (PBS) of the long-terminal repeat (LTR) retrotransposons as PCR primers. Amplification using the three most effective PBS primers generated 628 PCR amplicons, with an average of 209 amplicons. The average polymorphism level varied from 34% to 40% for all studied samples. Resolution analysis of the PBS primers showed all of them to have high or medium polymorphism levels, which varied from 0.763 to 0.965. Results of the molecular analysis of variance showed that the general biodiversity of A. ledebourianum populations is due to interpopulation (67%) and intrapopulation (33%) differences. The revealed genetic diversity was higher in the most distant population of A. ledebourianum LD64, located on the Sarymsakty ridge of Southern Altai. This is the first genetic diversity study of the endemic species A. ledebourianum using DNA profiling approaches. This work allowed us to collect new genetic data on the structure of A. ledebourianum populations in the Altai for subsequent development of preservation strategies to enhance the reproduction of this relict species. The results will be useful for the conservation and exploitation of this species, serving as the basis for further studies of its evolution and ecology.
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Affiliation(s)
- Oxana Khapilina
- National Center for Biotechnology, Korgalzhin Hwy 13/5, Nur-Sultan 010000, Kazakhstan; (A.T.); (A.T.); (V.S.)
| | - Ainur Turzhanova
- National Center for Biotechnology, Korgalzhin Hwy 13/5, Nur-Sultan 010000, Kazakhstan; (A.T.); (A.T.); (V.S.)
| | - Alevtina Danilova
- Altai Botanical Garden, Yermakova Str 1, Ridder 070000, Kazakhstan; (A.D.); (Y.K.)
| | - Asem Tumenbayeva
- National Center for Biotechnology, Korgalzhin Hwy 13/5, Nur-Sultan 010000, Kazakhstan; (A.T.); (A.T.); (V.S.)
| | - Vladislav Shevtsov
- National Center for Biotechnology, Korgalzhin Hwy 13/5, Nur-Sultan 010000, Kazakhstan; (A.T.); (A.T.); (V.S.)
| | - Yuri Kotukhov
- Altai Botanical Garden, Yermakova Str 1, Ridder 070000, Kazakhstan; (A.D.); (Y.K.)
| | - Ruslan Kalendar
- National Laboratory Astana, Nazarbayev University, Nur-Sultan 010000, Kazakhstan
- Helsinki Institute of Life Science HiLIFE, Biocenter 3, Viikinkaari 1, University of Helsinki, FI-00014 Helsinki, Finland
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Yañez-Santos AM, Paz RC, Paz-Sepúlveda PB, Urdampilleta JD. Full-length LTR retroelements in Capsicum annuum revealed a few species-specific family bursts with insertional preferences. Chromosome Res 2021; 29:261-284. [PMID: 34086192 DOI: 10.1007/s10577-021-09663-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 01/01/2023]
Abstract
Capsicum annuum is a species that has undergone an expansion of the size of its genome caused mainly by the amplification of repetitive DNA sequences, including mobile genetic elements. Based on information obtained from sequencing the genome of pepper, the estimated fraction of retroelements is approximately 81%, and previous results revealed an important contribution of lineages derived from Gypsy superfamily. However, the dynamics of the retroelements in the C. annuum genome is poorly understood. In this way, the present work seeks to investigate the phylogenetic diversity and genomic abundance of the families of autonomous (complete and intact) LTR retroelements from C. annuum and inspect their distribution along its chromosomes. In total, we identified 1151 structurally full-length retroelements (340 Copia; 811 Gypsy) grouped in 124 phylogenetic families in the base of their retrotranscriptase. All the evolutive lineages of LTR retroelements identified in plants were present in pepper; however, three of them comprise 83% of the entire LTR retroelements population, the lineages Athila, Del/Tekay, and Ale/Retrofit. From them, only three families represent 70.8% of the total number of the identified retroelements. A massive family-specific wave of amplification of two of them occurred in the last 0.5 Mya (GypsyCa_16; CopiaCa_01), whereas the third is more ancient and occurred 3.0 Mya (GypsyCa_13). Fluorescent in situ hybridization performed with family and lineage-specific probes revealed contrasting patterns of chromosomal affinity. Our results provide a database of the populations LTR retroelements specific to C. annuum genome. The most abundant families were analyzed according to chromosome insertional preferences, suppling useful tools to the design of retroelement-based markers specific to the species.
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Affiliation(s)
- Anahí Mara Yañez-Santos
- CIGEOBIO (FCEFyN, UNSJ/CONICET), Av. Ignacio de la Roza 590 (Oeste), J5402DCS, Rivadavia, San Juan, Argentina.,Instituto Multidisciplinario de Biología Vegetal (IMBIV), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Nacional de Córdoba (UNC), Córdoba, Argentina
| | - Rosalía Cristina Paz
- CIGEOBIO (FCEFyN, UNSJ/CONICET), Av. Ignacio de la Roza 590 (Oeste), J5402DCS, Rivadavia, San Juan, Argentina.
| | - Paula Beatriz Paz-Sepúlveda
- Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina (CONICET) - Comisión de Investigaciones Científicas (CIC) - Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Juan Domingo Urdampilleta
- Instituto Multidisciplinario de Biología Vegetal (IMBIV), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Nacional de Córdoba (UNC), Córdoba, Argentina
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Retrotransposable Elements: DNA Fingerprinting and the Assessment of Genetic Diversity. Methods Mol Biol 2021; 2222:263-286. [PMID: 33301099 DOI: 10.1007/978-1-0716-0997-2_15] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Retrotransposable elements (RTEs) are highly common mobile genetic elements that are composed of several classes and make up the majority of eukaryotic genomes. The "copy-out and paste-in" life cycle of replicative transposition in these dispersive and ubiquitous RTEs leads to new genome insertions without excision of the original element. RTEs are important drivers of species diversity; they exhibit great variety in structure, size, and mechanisms of transposition, making them important putative components in genome evolution. Accordingly, various applications have been developed to explore the polymorphisms in RTE insertion patterns. These applications include conventional or anchored polymerase chain reaction (PCR) and quantitative or digital PCR with primers designed for the 5' or 3' junction. Marker systems exploiting these PCR methods can be easily developed and are inexpensively used in the absence of extensive genome sequence data. The main inter-repeat amplification polymorphism techniques include inter-retrotransposon amplified polymorphism (IRAP), retrotransposon microsatellite amplified polymorphism (REMAP), and Inter-Primer Binding Site (iPBS) for PCR amplification with a single or two primers.
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Tomita M, Kanzaki T, Tanaka E. Clustered and dispersed chromosomal distribution of the two classes of Revolver transposon family in rye (Secale cereale). J Appl Genet 2021; 62:365-372. [PMID: 33694103 DOI: 10.1007/s13353-021-00617-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/27/2021] [Accepted: 02/05/2021] [Indexed: 11/26/2022]
Abstract
The chromosomal locations of a new class of Revolver transposon-like elements were analyzed by using FISH method on the metaphase chromosome in somatic cell division of the rye cultivar Petkus. First, the Revolver standard element probe λ2 was weakly hybridized throughout the rye chromosome, and comparatively large interstitial signals spotted with a dot shape were detected together with several telomeric regions. The dot shape interstitial signal was stably detected at one site on Chromosome (Chr) 1R (middle part of the interstitial region of the short arm), three sites on Chr 2R (distal part of the interstitial region and adjacent to the centromere on the short arm, middle part of the interstitial region of the long arm), and two sites on Chr 5R (middle part of the interstitial region and adjacent to the centromere on the long arm). The Revolver λ2 probe was effective for identification of 1R, 2R, and 5R chromosomes. On the other hand, Revolver nonautonomous element-specific L626-BARE-100 probe was strongly distributed throughout the rye chromosomes, and considerable numbers and diverse lengths of transcripts were detected by RT-PCR. Although the standard elements were found in localized clusters, the nonautonomous elements tended to be dispersed throughout the genome. Clustered nature of Revolver is a significantly rare case in genomics.
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Affiliation(s)
- Motonori Tomita
- Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan.
| | - Takaaki Kanzaki
- Faculty of Agriculture, Tottori University, 4-101 Koyama Minami, Tottori, 680-8550, Japan
| | - Eri Tanaka
- Faculty of Agriculture, Tottori University, 4-101 Koyama Minami, Tottori, 680-8550, Japan
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Khapilina O, Raiser O, Danilova A, Shevtsov V, Turzhanova A, Kalendar R. DNA profiling and assessment of genetic diversity of relict species Allium altaicum Pall. on the territory of Altai. PeerJ 2021; 9:e10674. [PMID: 33510974 PMCID: PMC7798630 DOI: 10.7717/peerj.10674] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 12/09/2020] [Indexed: 12/18/2022] Open
Abstract
Analysis of the genetic diversity of natural populations of threatened and endangered species of plants is a main aspect of conservation strategy. The endangered species Allium altaicum is a relict plant of the Ice Age and natural populations are located in extreme climatic conditions of Kazakstan's Altai Mountains. Mobile genetic elements and other interspersed repeats are basic components of a eukaryote genome, which can activate under stress conditions and indirectly promote the survival of an organism against environmental stresses. Detections of chromosomal changes related to recombination processes of mobile genetic elements are performed by various PCR methods. These methods are based on interspersed repeat sequences and are an effective tool for research of biological diversity of plants and their variability. In our research, we used conservative sequences of tRNA primer binding sites (PBS) when initializing the retrotransposon replication as PCR primers to research the genetic diversity of 12 natural populations of A. altaicum found in various ecogeographic conditions of the Kazakhstani Altai. High efficiency of the PBS amplification method used was observed already at the intrapopulation level. Unique amplicons representative of a certain population were found at the intrapopulation level. Analysis of molecular dispersion revealed that the biodiversity of populations of mountainous and lowland A. altaicum is due to intrapopulation differences for climatic zones of habitation. This is likely conditional upon predominance of vegetative reproduction over seed reproduction in some populations. In the case of vegetative reproduction, somatic recombination related to the activity of mobile genetic elements are preserved in subsequent generations. This leads to an increase of intrapopulation genetic diversity. Thus, high genetic diversity was observed in populations such as A. altaicum located in the territory of the Kalbinskii Altai, whereas the minimum diversity was observed in the populations of the Leninororsk ecogeographic group. Distinctions between these populations were also identified depending on the areas of their distribution. Low-land and mid-mountain living environments are characterized by a great variety of shapes and plasticity. This work allowed us to obtain new genetic data on the structure of A. altaicum populations on the territory of the Kazakhstan Altai for the subsequent development of preservation and reproduction strategies for this relict species.
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Affiliation(s)
| | - Olesya Raiser
- National Center for Biotechnology, Nur-Sultan, Kazakhstan
| | | | | | | | - Ruslan Kalendar
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland.,National Laboratory Astana, Nazarbayev University, Nur-Sultan, Aqmola, Kazakhstan
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Turzhanova A, Khapilina ON, Tumenbayeva A, Shevtsov V, Raiser O, Kalendar R. Genetic diversity of Alternaria species associated with black point in wheat grains. PeerJ 2020; 8:e9097. [PMID: 32411537 PMCID: PMC7207207 DOI: 10.7717/peerj.9097] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 04/09/2020] [Indexed: 12/12/2022] Open
Abstract
The genus Alternaria is a widely distributed major plant pathogen that can act as a saprophyte in plant debris. Fungi of this genus frequently infect cereal crops and cause such diseases as black point and wheat leaf blight, which decrease the yield and quality of cereal products. A total of 25 Alternaria sp. isolates were collected from germ grains of various wheat cultivars from different geographic regions in Kazakhstan. We investigated the genetic relationships of the main Alternaria species related to black point disease of wheat in Kazakhstan, using the inter-primer binding site (iPBS) DNA profiling technique. We used 25 retrotransposon-based iPBS primers to identify the differences among and within Alternaria species populations, and analyzed the variation using clustering (UPGMA) and statistical approaches (AMOVA). Isolates of Alternaria species clustered into two main genetic groups, with species of A.alternata and A.tennuissima forming one cluster, and isolates of A. infectoria forming another. The genetic diversity found using retrotransposon profiles was strongly correlated with geographic data. Overall, the iPBS fingerprinting technique is highly informative and useful for the evaluation of genetic diversity and relationships of Alternaria species.
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Affiliation(s)
| | | | | | | | - Olesya Raiser
- National Center for Biotechnology, Nur-Sultan, Kazakhstan
| | - Ruslan Kalendar
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Uusimaa, Finland
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Kalendar R, Raskina O, Belyayev A, Schulman AH. Long Tandem Arrays of Cassandra Retroelements and Their Role in Genome Dynamics in Plants. Int J Mol Sci 2020; 21:ijms21082931. [PMID: 32331257 PMCID: PMC7215508 DOI: 10.3390/ijms21082931] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 02/07/2023] Open
Abstract
Retrotransposable elements are widely distributed and diverse in eukaryotes. Their copy number increases through reverse-transcription-mediated propagation, while they can be lost through recombinational processes, generating genomic rearrangements. We previously identified extensive structurally uniform retrotransposon groups in which no member contains the gag, pol, or env internal domains. Because of the lack of protein-coding capacity, these groups are non-autonomous in replication, even if transcriptionally active. The Cassandra element belongs to the non-autonomous group called terminal-repeat retrotransposons in miniature (TRIM). It carries 5S RNA sequences with conserved RNA polymerase (pol) III promoters and terminators in its long terminal repeats (LTRs). Here, we identified multiple extended tandem arrays of Cassandra retrotransposons within different plant species, including ferns. At least 12 copies of repeated LTRs (as the tandem unit) and internal domain (as a spacer), giving a pattern that resembles the cellular 5S rRNA genes, were identified. A cytogenetic analysis revealed the specific chromosomal pattern of the Cassandra retrotransposon with prominent clustering at and around 5S rDNA loci. The secondary structure of the Cassandra retroelement RNA is predicted to form super-loops, in which the two LTRs are complementary to each other and can initiate local recombination, leading to the tandem arrays of Cassandra elements. The array structures are conserved for Cassandra retroelements of different species. We speculate that recombination events similar to those of 5S rRNA genes may explain the wide variation in Cassandra copy number. Likewise, the organization of 5S rRNA gene sequences is very variable in flowering plants; part of what is taken for 5S gene copy variation may be variation in Cassandra number. The role of the Cassandra 5S sequences remains to be established.
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Affiliation(s)
- Ruslan Kalendar
- Department of Agricultural Sciences, University of Helsinki, P.O. Box 27 (Latokartanonkaari 5), FI-00014 Helsinki, Finland
- RSE “National Center for Biotechnology”, Korgalzhyn Highway 13/5, Nur-Sultan 010000, Kazakhstan
- Correspondence: (R.K.); (A.H.S.)
| | - Olga Raskina
- Institute of Evolution, University of Haifa, Mount Carmel, Haifa 31905, Israel;
| | - Alexander Belyayev
- Laboratory of Molecular Cytogenetics and Karyology, Institute of Botany of the ASCR, Zámek 1, CZ-252 43 Průhonice, Czech Republic;
| | - Alan H. Schulman
- Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
- Institute of Biotechnology and Viikki Plant Science Centre, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland
- Correspondence: (R.K.); (A.H.S.)
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10
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Low Long Terminal Repeat (LTR)-Retrotransposon Expression in Leaves of the Marine Phanerogam Posidonia Oceanica L. Life (Basel) 2020; 10:life10030030. [PMID: 32213979 PMCID: PMC7151569 DOI: 10.3390/life10030030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/14/2020] [Accepted: 03/21/2020] [Indexed: 12/29/2022] Open
Abstract
Seagrasses as Posidonia oceanica reproduce mostly by vegetative propagation, which can reduce genetic variability within populations. Since, in clonally propagated species, insurgence of genetic variability can be determined by the activity of transposable elements, we have estimated the activity of such repeat elements by measuring their expression level in the leaves of plants from a Mediterranean site, for which Illumina complementary DNA (cDNA) sequence reads (produced from RNAs isolated by leaves of plants from deep and shallow meadows) were publicly available. Firstly, we produced a collection of retrotransposon-related sequences and then mapped Illumina cDNA reads onto these sequences. With this approach, it was evident that Posidonia retrotransposons are, in general, barely expressed; only nine elements resulted transcribed at levels comparable with those of reference genes encoding tubulins and actins. Differences in transcript abundance were observed according to the superfamily and the lineage to which the retrotransposons belonged. Only small differences were observed between retrotransposon expression levels in leaves of shallow and deep Posidonia meadow stands, whereas one TAR/Tork element resulted differentially expressed in deep plants exposed to heat. It can be concluded that, in P. oceanica, the contribution of retrotransposon activity to genetic variability is reduced, although the nine specific active elements could actually produce new structural variations.
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11
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Lunardon A, Johnson NR, Hagerott E, Phifer T, Polydore S, Coruh C, Axtell MJ. Integrated annotations and analyses of small RNA-producing loci from 47 diverse plants. Genome Res 2020; 30:497-513. [PMID: 32179590 PMCID: PMC7111516 DOI: 10.1101/gr.256750.119] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/27/2020] [Indexed: 01/25/2023]
Abstract
Plant endogenous small RNAs (sRNAs) are important regulators of gene expression. There are two broad categories of plant sRNAs: microRNAs (miRNAs) and endogenous short interfering RNAs (siRNAs). MicroRNA loci are relatively well-annotated but compose only a small minority of the total sRNA pool; siRNA locus annotations have lagged far behind. Here, we used a large data set of published and newly generated sRNA sequencing data (1333 sRNA-seq libraries containing more than 20 billion reads) and a uniform bioinformatic pipeline to produce comprehensive sRNA locus annotations of 47 diverse plants, yielding more than 2.7 million sRNA loci. The two most numerous classes of siRNA loci produced mainly 24- and 21-nucleotide (nt) siRNAs, respectively. Most often, 24-nt-dominated siRNA loci occurred in intergenic regions, especially at the 5′-flanking regions of protein-coding genes. In contrast, 21-nt-dominated siRNA loci were most often derived from double-stranded RNA precursors copied from spliced mRNAs. Genic 21-nt-dominated loci were especially common from disease resistance genes, including from a large number of monocots. Individual siRNA sequences of all types showed very little conservation across species, whereas mature miRNAs were more likely to be conserved. We developed a web server where our data and several search and analysis tools are freely accessible.
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Affiliation(s)
- Alice Lunardon
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Nathan R Johnson
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Emily Hagerott
- Department of Biology, Knox College, Galesburg, Illinois 61401, USA
| | - Tamia Phifer
- Department of Biology, Knox College, Galesburg, Illinois 61401, USA
| | - Seth Polydore
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Ceyda Coruh
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Michael J Axtell
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Mascagni F, Vangelisti A, Usai G, Giordani T, Cavallini A, Natali L. A computational genome-wide analysis of long terminal repeats retrotransposon expression in sunflower roots (Helianthus annuus L.). Genetica 2020; 148:13-23. [PMID: 31960179 DOI: 10.1007/s10709-020-00085-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 01/17/2020] [Indexed: 11/24/2022]
Abstract
Long terminal repeats (LTR) retrotransposons have a major role in determining genome size, structure and function, thanks to their ability to transpose. We performed a meta-analysis of LTR-retrotransposon expression in roots of sunflower plantlets treated with different plant hormones, chemicals and NaCl. By using Illumina cDNA libraries, available from public repositories, we measured the number of reads matching the retrotranscriptase domains isolated from a whole genome library of retrotransposons. LTR-retrotransposons resulted in general barely expressed, except for 4 elements, all belonging to the AleII lineage, which showed high transcription levels in roots of both control and treated plants. The expression of retrotransposons in treated plants was slightly higher than in the control. Transcribed elements belonged to specific chromosomal loci and were not abundant in the genome. A few elements resulted differentially expressed depending on the treatment. Results suggest that, although most retrotransposons are not expressed, the transcription of such elements is related to their abundance, to their position in the chromosome and to their lineage.
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Affiliation(s)
- Flavia Mascagni
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Alberto Vangelisti
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Gabriele Usai
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Tommaso Giordani
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Andrea Cavallini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.
| | - Lucia Natali
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.
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High-throughput retrotransposon-based genetic diversity of maize germplasm assessment and analysis. Mol Biol Rep 2020; 47:1589-1603. [PMID: 31919750 DOI: 10.1007/s11033-020-05246-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 01/03/2020] [Indexed: 01/08/2023]
Abstract
Maize is one of the world's most important crops and a model for grass genome research. Long terminal repeat (LTR) retrotransposons comprise most of the maize genome; their ability to produce new copies makes them efficient high-throughput genetic markers. Inter-retrotransposon-amplified polymorphisms (IRAPs) were used to study the genetic diversity of maize germplasm. Five LTR retrotransposons (Huck, Tekay, Opie, Ji, and Grande) were chosen, based on their large number of copies in the maize genome, whereas polymerase chain reaction primers were designed based on consensus LTR sequences. The LTR primers showed high quality and reproducible DNA fingerprints, with a total of 677 bands including 392 polymorphic bands showing 58% polymorphism between maize hybrid lines. These markers were used to identify genetic similarities among all lines of maize. Analysis of genetic similarity was carried out based on polymorphic amplicon profiles and genetic similarity phylogeny analysis. This diversity was expected to display ecogeographical patterns of variation and local adaptation. The clustering method showed that the varieties were grouped into three clusters differing in ecogeographical origin. Each of these clusters comprised divergent hybrids with convergent characters. The clusters reflected the differences among maize hybrids and were in accordance with their pedigree. The IRAP technique is an efficient high-throughput genetic marker-generating method.
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Usai G, Mascagni F, Vangelisti A, Giordani T, Ceccarelli M, Cavallini A, Natali L. Interspecific hybridisation and LTR-retrotransposon mobilisation-related structural variation in plants: A case study. Genomics 2019; 112:1611-1621. [PMID: 31605729 DOI: 10.1016/j.ygeno.2019.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/13/2019] [Accepted: 09/12/2019] [Indexed: 11/30/2022]
Abstract
The dynamics of long-terminal-repeat retrotransposons in two poplar species (Populus deltoides and P. nigra) and in an interspecific hybrid, recently synthesized, were investigated by analyzing the genomic abundance and transcription levels of a collection of 828 full-length retroelements identified in the genome sequence of P. trichocarpa, all occurring also in the genomes of P. deltoides and P. nigra. Overall, genomic abundance and transcription levels of many retrotransposons in the hybrid resulted higher or lower than expected by calculating the mean of the parental values. A bioinformatics procedure was established to ascertain the occurrence of the same retrotransposon loci in the three genotypes. The results indicated that retrotransposon abundance variations between the hybrid and the mean value of the parents were due to i) co-segregation of retrotransposon high- or low-abundant haplotypes; ii) new retroelement insertions; iii) retrotransposon loss. Concerning retrotransposon expression, this was generally low, with only 14/828 elements over- or under-expressed in the hybrid than expected by calculating the mean of the parents. It is concluded that interspecific hybridisation between the two poplar species determine quantitative variation and differential expression of some retrotransposons, with possible consequences for the genetic differentiation of the hybrid.
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Affiliation(s)
- Gabriele Usai
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Flavia Mascagni
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Alberto Vangelisti
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Tommaso Giordani
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Marilena Ceccarelli
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di sotto 8, 06123 Perugia, Italy
| | - Andrea Cavallini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy.
| | - Lucia Natali
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy.
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Qiu F, Ungerer MC. Genomic abundance and transcriptional activity of diverse gypsy and copia long terminal repeat retrotransposons in three wild sunflower species. BMC PLANT BIOLOGY 2018; 18:6. [PMID: 29304730 PMCID: PMC5755311 DOI: 10.1186/s12870-017-1223-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 12/21/2017] [Indexed: 05/02/2023]
Abstract
BACKGROUND Long terminal repeat (LTR) retrotransposons are highly abundant in plant genomes and require transcriptional activity for their proliferative mode of replication. These sequences exist in plant genomes as diverse sublineages within the main element superfamilies (i.e., gypsy and copia). While transcriptional activity of these elements is increasingly recognized as a regular attribute of plant transcriptomes, it is currently unknown the extent to which different sublineages of these elements are transcriptionally active both within and across species. In the current report, we utilize next generation sequencing methods to examine genomic copy number abundance of diverse LTR retrotransposon sublineages and their corresponding levels of transcriptional activity in three diploid wild sunflower species, Helianthus agrestis, H. carnosus and H. porteri. RESULTS The diploid sunflower species under investigation differ in genome size 2.75-fold, with 2C values of 22.93 for H. agrestis, 12.31 for H. carnosus and 8.33 for H. porteri. The same diverse gypsy and copia sublineages of LTR retrotransposons were identified across species, but with gypsy sequences consistently more abundant than copia and with global gypsy sequence abundance positively correlated with nuclear genome size. Transcriptional activity was detected for multiple copia and gypsy sequences, with significantly higher activity levels detected for copia versus gypsy. Interestingly, of 11 elements identified as transcriptionally active, 5 exhibited detectable expression in all three species and 3 exhibited detectable expression in two species. CONCLUSIONS Combined analyses of LTR retrotransposon genomic abundance and transcriptional activity across three sunflower species provides novel insights into genome size evolution and transposable element dynamics in this group. Despite considerable variation in nuclear genome size among species, relatively conserved patterns of LTR retrotransposon transcriptional activity were observed, with a highly overlapping set of copia and gypsy sequences observed to be transcriptionally active across species. A higher proportion of copia versus gypsy elements were found to be transcriptionally active and these sequences also were expressed at higher levels.
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Affiliation(s)
- Fan Qiu
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA.
| | - Mark C Ungerer
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
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Markova DN, Mason-Gamer RJ. Transcriptional activity of PIF and Pong-like Class II transposable elements in Triticeae. BMC Evol Biol 2017; 17:178. [PMID: 28774284 PMCID: PMC5543537 DOI: 10.1186/s12862-017-1028-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 07/26/2017] [Indexed: 11/10/2022] Open
Abstract
Background Transposable elements are major contributors to genome size and variability, accounting for approximately 70–80% of the maize, barley, and wheat genomes. PIF and Pong-like elements belong to two closely-related element families within the PIF/Harbinger superfamily of Class II (DNA) transposons. Both elements contain two open reading frames; one encodes a transposase (ORF2) that catalyzes transposition of the functional elements and their related non-autonomous elements, while the function of the second is still debated. In this work, we surveyed for PIF- and Pong-related transcriptional activity in 13 diploid Triticeae species, all of which have been previously shown to harbor extensive within-genome diversity of both groups of elements. Results The results revealed that PIF elements have considerable transcriptional activity in Triticeae, suggesting that they can escape the initial levels of plant cell control and are regulated at the post-transcriptional level. Phylogenetic analysis of 156 PIF cDNA transposase fragments along with 240 genomic partial transposase sequences showed that most, if not all, PIF clades are transcriptionally competent, and that multiple transposases coexisting within a single genome have the potential to act simultaneously. In contrast, we did not detect any transcriptional activity of Pong elements in any sample. Conclusions The lack of Pong element transcription shows that even closely related transposon families can exhibit wide variation in their transposase transcriptional activity within the same genome. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-1028-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dragomira N Markova
- Department of Biological Sciences, University of Illinois at Chicago, M/C 067 840 West Taylor Street, Chicago, IL, 60607, USA. .,Present address: Department of Plant Sciences (mail stop 3), 151 Asmundson Hall, University of California, Davis, CA, 95616, USA.
| | - Roberta J Mason-Gamer
- Department of Biological Sciences, University of Illinois at Chicago, M/C 067 840 West Taylor Street, Chicago, IL, 60607, USA
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Filho JAF, de Brito LS, Leão AP, Alves AA, Formighieri EF, Júnior MTS. In Silico Approach for Characterization and Comparison of Repeats in the Genomes of Oil and Date Palms. Bioinform Biol Insights 2017; 11:1177932217702388. [PMID: 28469420 PMCID: PMC5402704 DOI: 10.1177/1177932217702388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 03/02/2017] [Indexed: 11/16/2022] Open
Abstract
Transposable elements (TEs) are mobile genetic elements present in almost all eukaryotic genomes. Due to their typical patterns of repetition, discovery, and characterization, they demand analysis by various bioinformatics software. Probably, as a result of the need for a complex analysis, many genomes publicly available do not have these elements annotated yet. In this study, a de novo and homology-based identification of TEs and microsatellites was performed using genomic data from 3 palm species: Elaeis oleifera (American oil palm, v.1, Embrapa, unpublished; v.8, Malaysian Palm Oil Board [MPOB], public), Elaeis guineensis (African oil palm, v.5, MPOB, public), and Phoenix dactylifera (date palm). The estimated total coverage of TEs was 50.96% (523 572 kb) and 42.31% (593 463 kb), 39.41% (605 015 kb), and 33.67% (187 361 kb), respectively. A total of 155 726 microsatellite loci were identified in the genomes of oil and date palms. This is the first detailed description of repeats in the genomes of oil and date palms. A relatively high diversity and abundance of TEs were found in the genomes, opening a range of further opportunities for applied research in these genera. The development of molecular markers (mainly simple sequence repeat), which may be immediately applied in breeding programs of those species to support the selection of superior genotypes and to enhance knowledge of the genetic structure of the breeding and natural populations, is the most notable opportunity.
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Affiliation(s)
- Jaire Alves Ferreira Filho
- Graduate Program in Plant Biotechnology, Federal University of Lavras (UFLA), Lavras, Brazil.,Embrapa Agroenergia, Parque Estação Biológica (PqEB), Brasília, Brazil.,Center of Molecular Biology and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Campinas, Brazil
| | | | | | | | | | - Manoel Teixeira Souza Júnior
- Graduate Program in Plant Biotechnology, Federal University of Lavras (UFLA), Lavras, Brazil.,Embrapa Agroenergia, Parque Estação Biológica (PqEB), Brasília, Brazil
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Useful parasites: the evolutionary biology and biotechnology applications of transposable elements. J Genet 2017; 95:1039-1052. [PMID: 27994207 DOI: 10.1007/s12041-016-0702-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Transposable elements usually comprise the most abundant nongenic fraction of eukaryotic genomes. Because of their capacity to selfreplicate and to induce a wide range of mutations, transposable elements have long been considered as 'parasitic' or 'selfish'. Today, we recognize that the findings about genomic changes affected by transposable elements have considerably altered our view of the ways in which genomes evolve and work. Numerous studies have provided evidences that mobile elements have the potential to act as agents of evolution by increasing, rearranging and diversifying the genetic repertoire of their hosts. With large-scale sequencing becoming increasingly available, more and more scientists come across transposable element sequences in their data. I will provide examples that transposable elements, although having signatures of 'selfish' DNA, play a significant biological role in the maintainance of genome integrity and providing novel regulatoty networks. These features, along with the transpositional and mutagenic capacity to produce a raw genetic diversity, make the genome mobile fraction, a key player in species adaptation and microevolution. The last but not least, transposable elements stand as informative DNA markers that may complement other conventional DNA markers. Altogether, transposable elements represent a promising, but still largely unexplored research niche and deserve to be included into the agenda of molecular ecologists, evolutionary geneticists, conservation biologists and plant breeders.
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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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20
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Kalinka A, Achrem M, Poter P. The DNA methylation level against the background of the genome size and t-heterochromatin content in some species of the genus Secale L. PeerJ 2017; 5:e2889. [PMID: 28149679 PMCID: PMC5267573 DOI: 10.7717/peerj.2889] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 12/08/2016] [Indexed: 01/05/2023] Open
Abstract
Methylation of cytosine in DNA is one of the most important epigenetic modifications in eukaryotes and plays a crucial role in the regulation of gene activity and the maintenance of genomic integrity. DNA methylation and other epigenetic mechanisms affect the development, differentiation or the response of plants to biotic and abiotic stress. This study compared the level of methylation of cytosines on a global (ELISA) and genomic scale (MSAP) between the species of the genus Secale. We analyzed whether the interspecific variation of cytosine methylation was associated with the size of the genome (C-value) and the content of telomeric heterochromatin. MSAP analysis showed that S. sylvestre was the most distinct species among the studied rye taxa; however, the results clearly indicated that these differences were not statistically significant. The total methylation level of the studied loci was very similar in all taxa and ranged from 60% in S. strictum ssp. africanum to 66% in S. cereale ssp. segetale, which confirmed the lack of significant differences in the sequence methylation pattern between the pairs of rye taxa. The level of global cytosine methylation in the DNA was not significantly associated with the content of t-heterochromatin and did not overlap with the existing taxonomic rye relationships. The highest content of 5-methylcytosine was found in S. cereale ssp. segetale (83%), while very low in S. strictum ssp. strictum (53%), which was significantly different from the methylation state of all taxa, except for S. sylvestre. The other studied taxa of rye had a similar level of methylated cytosine ranging from 66.42% (S. vavilovii) to 74.41% in (S. cereale ssp. afghanicum). The results obtained in this study are evidence that the percentage of methylated cytosine cannot be inferred solely based on the genome size or t-heterochromatin. This is a significantly more complex issue.
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Affiliation(s)
- Anna Kalinka
- Department of Cell Biology, Faculty of Biology, University of Szczecin, Szczecin, Poland; Molecular Biology and Biotechnology Center, Faculty of Biology, University of Szczecin, Szczecin, Poland
| | - Magdalena Achrem
- Department of Cell Biology, Faculty of Biology, University of Szczecin, Szczecin, Poland; Molecular Biology and Biotechnology Center, Faculty of Biology, University of Szczecin, Szczecin, Poland
| | - Paulina Poter
- Department of Cell Biology, Faculty of Biology, University of Szczecin , Szczecin , Poland
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Galván-Gordillo SV, Concepción Martínez-Navarro A, Xoconostle-Cázares B, Ruiz-Medrano R. Bioinformatic analysis of Arabidopsis reverse transcriptases with a zinc-finger domain. Biologia (Bratisl) 2016. [DOI: 10.1515/biolog-2016-0145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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22
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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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Grandbastien MA. LTR retrotransposons, handy hitchhikers of plant regulation and stress response. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:403-16. [DOI: 10.1016/j.bbagrm.2014.07.017] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/21/2014] [Accepted: 07/23/2014] [Indexed: 11/30/2022]
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25
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Santos AA, Penha HA, Bellec A, Munhoz CDF, Pedrosa-Harand A, Bergès H, Vieira MLC. Begin at the beginning: A BAC-end view of the passion fruit (Passiflora) genome. BMC Genomics 2014; 15:816. [PMID: 25260959 PMCID: PMC4189760 DOI: 10.1186/1471-2164-15-816] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 09/22/2014] [Indexed: 12/16/2022] Open
Abstract
Background The passion fruit (Passiflora edulis) is a tropical crop of economic importance both for juice production and consumption as fresh fruit. The juice is also used in concentrate blends that are consumed worldwide. However, very little is known about the genome of the species. Therefore, improving our understanding of passion fruit genomics is essential and to some degree a pre-requisite if its genetic resources are to be used more efficiently. In this study, we have constructed a large-insert BAC library and provided the first view on the structure and content of the passion fruit genome, using BAC-end sequence (BES) data as a major resource. Results The library consisted of 82,944 clones and its levels of organellar DNA were very low. The library represents six haploid genome equivalents, and the average insert size was 108 kb. To check its utility for gene isolation, successful macroarray screening experiments were carried out with probes complementary to eight Passiflora gene sequences available in public databases. BACs harbouring those genes were used in fluorescent in situ hybridizations and unique signals were detected for four BACs in three chromosomes (n = 9). Then, we explored 10,000 BES and we identified reads likely to contain repetitive mobile elements (19.6% of all BES), simple sequence repeats and putative proteins, and to estimate the GC content (~42%) of the reads. Around 9.6% of all BES were found to have high levels of similarity to plant genes and ontological terms were assigned to more than half of the sequences analysed (940). The vast majority of the top-hits made by our sequences were to Populus trichocarpa (24.8% of the total occurrences), Theobroma cacao (21.6%), Ricinus communis (14.3%), Vitis vinifera (6.5%) and Prunus persica (3.8%). Conclusions We generated the first large-insert library for a member of Passifloraceae. This BAC library provides a new resource for genetic and genomic studies, as well as it represents a valuable tool for future whole genome study. Remarkably, a number of BAC-end pair sequences could be mapped to intervals of the sequenced Arabidopsis thaliana, V. vinifera and P. trichocarpa chromosomes, and putative collinear microsyntenic regions were identified. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-816) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | - Maria Lucia Carneiro Vieira
- Departamento de Genética, Universidade de São Paulo, Escola Superior de Agricultura "Luiz de Queiroz", P,O, Box 83, 13400-970 Piracicaba, Brazil.
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Das B, Sengupta S, Prasad M, Ghose TK. Genetic diversity of the conserved motifs of six bacterial leaf blight resistance genes in a set of rice landraces. BMC Genet 2014; 15:82. [PMID: 25016378 PMCID: PMC4105243 DOI: 10.1186/1471-2156-15-82] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 07/10/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacterial leaf blight (BLB) caused by the vascular pathogen Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious diseases leading to crop failure in rice growing countries. A total of 37 resistance genes against Xoo has been identified in rice. Of these, ten BLB resistance genes have been mapped on rice chromosomes, while 6 have been cloned, sequenced and characterized. Diversity analysis at the resistance gene level of this disease is scanty, and the landraces from West Bengal and North Eastern states of India have received little attention so far. The objective of this study was to assess the genetic diversity at conserved domains of 6 BLB resistance genes in a set of 22 rice accessions including landraces and check genotypes collected from the states of Assam, Nagaland, Mizoram and West Bengal. RESULTS In this study 34 pairs of primers were designed from conserved domains of 6 BLB resistance genes; Xa1, xa5, Xa21, Xa21(A1), Xa26 and Xa27. The designed primer pairs were used to generate PCR based polymorphic DNA profiles to detect and elucidate the genetic diversity of the six genes in the 22 diverse rice accessions of known disease phenotype. A total of 140 alleles were identified including 41 rare and 26 null alleles. The average polymorphism information content (PIC) value was 0.56/primer pair. The DNA profiles identified each of the rice landraces unequivocally. The amplified polymorphic DNA bands were used to calculate genetic similarity of the rice landraces in all possible pair combinations. The similarity among the rice accessions ranged from 18% to 89% and the dendrogram produced from the similarity values was divided into 2 major clusters. The conserved domains identified within the sequenced rare alleles include Leucine-Rich Repeat, BED-type zinc finger domain, sugar transferase domain and the domain of the carbohydrate esterase 4 superfamily. CONCLUSIONS This study revealed high genetic diversity at conserved domains of six BLB resistance genes in a set of 22 rice accessions. The inclusion of more genotypes from remote ecological niches and hotspots holds promise for identification of further genetic diversity at the BLB resistance genes.
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Affiliation(s)
| | | | | | - Tapas Kumar Ghose
- Division of Plant Biology, Bose Institute, Main Campus, 93/1 A,P,C, Road, 700009 Kolkata, West Bengal, India.
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Yilmaz S, Gozukirmizi N. Variation of Retrotransposon Movement in Callus Culture and Regenerated Shoots of Barley. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/bbeq.2013.0076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Marakli S, Yilmaz S, Gozukirmizi N. BARE1andBAGY2Retrotransposon Movements and Expression Analyses in Developing Barley Seedlings. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/bbeq.2012.0112] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Analysis of T-DNA/Host-Plant DNA Junction Sequences in Single-Copy Transgenic Barley Lines. BIOLOGY 2014; 3:39-55. [PMID: 24833334 PMCID: PMC4009757 DOI: 10.3390/biology3010039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/03/2014] [Accepted: 01/03/2014] [Indexed: 01/19/2023]
Abstract
Sequencing across the junction between an integrated transfer DNA (T-DNA) and a host plant genome provides two important pieces of information. The junctions themselves provide information regarding the proportion of T-DNA which has integrated into the host plant genome, whilst the transgene flanking sequences can be used to study the local genetic environment of the integrated transgene. In addition, this information is important in the safety assessment of GM crops and essential for GM traceability. In this study, a detailed analysis was carried out on the right-border T-DNA junction sequences of single-copy independent transgenic barley lines. T-DNA truncations at the right-border were found to be relatively common and affected 33.3% of the lines. In addition, 14.3% of lines had rearranged construct sequence after the right border break-point. An in depth analysis of the host-plant flanking sequences revealed that a significant proportion of the T-DNAs integrated into or close to known repetitive elements. However, this integration into repetitive DNA did not have a negative effect on transgene expression.
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Jääskeläinen M, Chang W, Moisy C, Schulman AH. Retrotransposon BARE displays strong tissue-specific differences in expression. THE NEW PHYTOLOGIST 2013; 200:1000-8. [PMID: 24033286 DOI: 10.1111/nph.12470] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 07/30/2013] [Indexed: 05/25/2023]
Abstract
The BARE retrotransposon comprises c. 10% of the barley (Hordeum vulgare) genome. It is actively transcribed, translated and forms virus-like particles (VLPs). For retrotransposons, the inheritance of new copies depends critically on where in the plant replication occurs. In order to shed light on the replication strategy of BARE in the plant, we have used immunolocalization and in situ hybridization to examine expression of the BARE capsid protein, Gag, at a tissue-specific level. Gag is expressed in provascular tissues and highly localized in companion cells surrounding the phloem sieve tubes in mature vascular tissues. BARE Gag and RNA was not seen in the shoot apical meristem of young seedlings, but appeared, following transition to flowering, in the developing floral spike. Moreover, Gag has a highly specific localization in pre-fertilization ovaries. The strong presence of Gag in the floral meristems suggests that newly replicated copies there will be passed to the next generation. BARE expression patterns are consistent with transcriptional regulation by predicted response elements in the BARE promoter, and in the ovary with release from epigenetic transcriptional silencing. To our knowledge, this is the first analysis of the expression of native retrotransposon proteins within a plant to be reported.
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Affiliation(s)
- Marko Jääskeläinen
- MTT/BI Plant Genomics Laboratory, Institute of Biotechnology, Viikki Biocenter, University of Helsinki, PO Box 65, Viikinkaari 1, FIN-00014, Helsinki, Finland
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Ben-David S, Yaakov B, Kashkush K. Genome-wide analysis of short interspersed nuclear elements SINES revealed high sequence conservation, gene association and retrotranspositional activity in wheat. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 76:201-10. [PMID: 23855320 PMCID: PMC4223381 DOI: 10.1111/tpj.12285] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/04/2013] [Accepted: 07/03/2013] [Indexed: 05/02/2023]
Abstract
Short interspersed nuclear elements (SINEs) are non-autonomous non-LTR retroelements that are present in most eukaryotic species. While SINEs have been intensively investigated in humans and other animal systems, they are poorly studied in plants, especially in wheat (Triticum aestivum). We used quantitative PCR of various wheat species to determine the copy number of a wheat SINE family, termed Au SINE, combined with computer-assisted analyses of the publicly available 454 pyrosequencing database of T. aestivum. In addition, we utilized site-specific PCR on 57 Au SINE insertions, transposon methylation display and transposon display on newly formed wheat polyploids to assess retrotranspositional activity, epigenetic status and genetic rearrangements in Au SINE, respectively. We retrieved 3706 different insertions of Au SINE from the 454 pyrosequencing database of T. aestivum, and found that most of the elements are inserted in A/T-rich regions, while approximately 38% of the insertions are associated with transcribed regions, including known wheat genes. We observed typical retrotransposition of Au SINE in the second generation of a newly formed wheat allohexaploid, and massive hypermethylation in CCGG sites surrounding Au SINE in the third generation. Finally, we observed huge differences in the copy numbers in diploid Triticum and Aegilops species, and a significant increase in the copy numbers in natural wheat polyploids, but no significant increase in the copy number of Au SINE in the first four generations for two of three newly formed allopolyploid species used in this study. Our data indicate that SINEs may play a prominent role in the genomic evolution of wheat through stress-induced activation.
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Schulman AH. Retrotransposon replication in plants. Curr Opin Virol 2013; 3:604-14. [PMID: 24035277 DOI: 10.1016/j.coviro.2013.08.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 12/31/2022]
Abstract
Retrotransposons comprise the bulk of large plant genomes, replicating via an RNA intermediate whereby the original, integrated element remains in place. Of the two main orders, the LTR retrotransposons considerably outnumber the LINEs. LINEs integrate into target sites simultaneously with the RNA transcript being copied into cDNA by target-primed reverse transcription. LTR retrotransposon replication is basically equivalent to the intracellular phase of retroviral life cycles. The envelope gene giving extracellular mobility to retroviruses is in fact widespread in plants and their retrotransposons. Evolutionary analyses of the retrotransposons and retroviruses suggest that both form an ancient monophyletic group. The particular adaptations of LTR retrotransposons to plant life cycles enabling their success remain to be clarified.
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Affiliation(s)
- Alan H Schulman
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, P.O. Box 65, Helsinki FIN-00014, Finland; Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen FIN-31600, Finland.
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Chang W, Jääskeläinen M, Li SP, Schulman AH. BARE retrotransposons are translated and replicated via distinct RNA pools. PLoS One 2013; 8:e72270. [PMID: 23940808 PMCID: PMC3735527 DOI: 10.1371/journal.pone.0072270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/14/2013] [Indexed: 01/02/2023] Open
Abstract
The replication of Long Terminal Repeat (LTR) retrotransposons, which can constitute over 80% of higher plant genomes, resembles that of retroviruses. A major question for retrotransposons and retroviruses is how the two conflicting roles of their transcripts, in translation and reverse transcription, are balanced. Here, we show that the BARE retrotransposon, despite its organization into just one open reading frame, produces three distinct classes of transcripts. One is capped, polyadenylated, and translated, but cannot be copied into cDNA. The second is not capped or polyadenylated, but is destined for packaging and ultimate reverse transcription. The third class is capped, polyadenylated, and spliced to favor production of a subgenomic RNA encoding only Gag, the protein forming virus-like particles. Moreover, the BARE2 subfamily, which cannot synthesize Gag and is parasitic on BARE1, does not produce the spliced sub-genomic RNA for translation but does make the replication competent transcripts, which are packaged into BARE1 particles. To our knowledge, this is first demonstration of distinct RNA pools for translation and transcription for any retrotransposon.
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Affiliation(s)
- Wei Chang
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
| | - Marko Jääskeläinen
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
| | - Song-ping Li
- Genome-Scale Biology Program, University of Helsinki, Biomedicum, Helsinki, Finland
| | - Alan H. Schulman
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
- Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland
- * E-mail:
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Bonchev G, Parisod C. Transposable elements and microevolutionary changes in natural populations. Mol Ecol Resour 2013; 13:765-75. [DOI: 10.1111/1755-0998.12133] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/31/2013] [Accepted: 06/04/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Georgi Bonchev
- Laboratory of evolutionary botany Institute of biology University of Neuchâtel Rue Emile‐Argand 11 CH‐2000 Neuchâtel Switzerland
- Institute of plant physiology and genetics Bulgarian academy of sciences G. Bonchev Street, Bldg 24 Sofia 1113 Bulgaria
| | - Christian Parisod
- Laboratory of evolutionary botany Institute of biology University of Neuchâtel Rue Emile‐Argand 11 CH‐2000 Neuchâtel Switzerland
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Petti C, Shearer A, Tateno M, Ruwaya M, Nokes S, Brutnell T, DeBolt S. Comparative feedstock analysis in Setaria viridis L. as a model for C4 bioenergy grasses and Panicoid crop species. FRONTIERS IN PLANT SCIENCE 2013; 4:181. [PMID: 23802002 PMCID: PMC3685855 DOI: 10.3389/fpls.2013.00181] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 05/20/2013] [Indexed: 05/18/2023]
Abstract
Second generation feedstocks for bioethanol will likely include a sizable proportion of perennial C4 grasses, principally in the Panicoideae clade. The Panicoideae contain agronomically important annual grasses including Zea mays L. (maize), Sorghum bicolor (L.) Moench (sorghum), and Saccharum officinarum L. (sugar cane) as well as promising second generation perennial feedstocks including Miscanthus×giganteus and Panicum virgatum L. (switchgrass). The underlying complexity of these polyploid grass genomes is a major limitation for their direct manipulation and thus driving a need for rapidly cycling comparative model. Setaria viridis (green millet) is a rapid cycling C4 panicoid grass with a relatively small and sequenced diploid genome and abundant seed production. Stable, transient, and protoplast transformation technologies have also been developed for Setaria viridis making it a potentially excellent model for other C4 bioenergy grasses. Here, the lignocellulosic feedstock composition, cellulose biosynthesis inhibitor response and saccharification dynamics of Setaria viridis are compared with the annual sorghum and maize and the perennial switchgrass bioenergy crops as a baseline study into the applicability for translational research. A genome-wide systematic investigation of the cellulose synthase-A genes was performed identifying eight candidate sequences. Two developmental stages; (a) metabolically active young tissue and (b) metabolically plateaued (mature) material are examined to compare biomass performance metrics.
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Affiliation(s)
- Carloalberto Petti
- Plant Physiology, Department of Horticulture, College of Agriculture, Food and the Environment, University of KentuckyLexington, KY, USA
| | - Andrew Shearer
- Plant Physiology, Department of Horticulture, College of Agriculture, Food and the Environment, University of KentuckyLexington, KY, USA
| | - Mizuki Tateno
- Plant Physiology, Department of Horticulture, College of Agriculture, Food and the Environment, University of KentuckyLexington, KY, USA
| | - Matthew Ruwaya
- Department of Biosystems and Agricultural Engineering, University of KentuckyLexington, KY, USA
| | - Sue Nokes
- Department of Biosystems and Agricultural Engineering, University of KentuckyLexington, KY, USA
| | - Tom Brutnell
- Enterprise Institute for Renewable Fuels, Donald Danforth Plant Science CenterSt. Louis MO, USA
| | - Seth DeBolt
- Plant Physiology, Department of Horticulture, College of Agriculture, Food and the Environment, University of KentuckyLexington, KY, USA
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Lu X, Chen D, Shu D, Zhang Z, Wang W, Klukas C, Chen LL, Fan Y, Chen M, Zhang C. The differential transcription network between embryo and endosperm in the early developing maize seed. PLANT PHYSIOLOGY 2013; 162:440-55. [PMID: 23478895 PMCID: PMC3641222 DOI: 10.1104/pp.113.214874] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 03/07/2013] [Indexed: 05/21/2023]
Abstract
Transcriptome analysis of early-developing maize (Zea mays) seed was conducted using Illumina sequencing. We mapped 11,074,508 and 11,495,788 paired-end reads from endosperm and embryo, respectively, at 9 d after pollination to define gene structure and alternative splicing events as well as transcriptional regulators of gene expression to quantify transcript abundance in both embryo and endosperm. We identified a large number of novel transcribed regions that did not fall within maize annotated regions, and many of the novel transcribed regions were tissue-specifically expressed. We found that 50.7% (8,556 of 16,878) of multiexonic genes were alternatively spliced, and some transcript isoforms were specifically expressed either in endosperm or in embryo. In addition, a total of 46 trans-splicing events, with nine intrachromosomal events and 37 interchromosomal events, were found in our data set. Many metabolic activities were specifically assigned to endosperm and embryo, such as starch biosynthesis in endosperm and lipid biosynthesis in embryo. Finally, a number of transcription factors and imprinting genes were found to be specifically expressed in embryo or endosperm. This data set will aid in understanding how embryo/endosperm development in maize is differentially regulated.
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Senerchia N, Wicker T, Felber F, Parisod C. Evolutionary dynamics of retrotransposons assessed by high-throughput sequencing in wild relatives of wheat. Genome Biol Evol 2013; 5:1010-20. [PMID: 23595021 PMCID: PMC4104650 DOI: 10.1093/gbe/evt064] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2013] [Indexed: 12/23/2022] Open
Abstract
Transposable elements (TEs) represent a major fraction of plant genomes and drive their evolution. An improved understanding of genome evolution requires the dynamics of a large number of TE families to be considered. We put forward an approach bypassing the required step of a complete reference genome to assess the evolutionary trajectories of high copy number TE families from genome snapshot with high-throughput sequencing. Low coverage sequencing of the complex genomes of Aegilops cylindrica and Ae. geniculata using 454 identified more than 70% of the sequences as known TEs, mainly long terminal repeat (LTR) retrotransposons. Comparing the abundance of reads as well as patterns of sequence diversity and divergence within and among genomes assessed the dynamics of 44 major LTR retrotransposon families of the 165 identified. In particular, molecular population genetics on individual TE copies distinguished recently active from quiescent families and highlighted different evolutionary trajectories of retrotransposons among related species. This work presents a suite of tools suitable for current sequencing data, allowing to address the genome-wide evolutionary dynamics of TEs at the family level and advancing our understanding of the evolution of nonmodel genomes.
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Affiliation(s)
- Natacha Senerchia
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Switzerland
| | - Thomas Wicker
- Institute of Plant Biology, University of Zurich, Switzerland
| | - François Felber
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Switzerland
- Musée et Jardins botaniques cantonaux, Lausanne, Switzerland
| | - Christian Parisod
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Switzerland
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Posttraumatic regeneration involves differential expression of long terminal repeat (LTR) retrotransposons. Dev Dyn 2012; 241:1625-36. [DOI: 10.1002/dvdy.23844] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2012] [Indexed: 12/26/2022] Open
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Schulman AH, Flavell AJ, Paux E, Ellis THN. The application of LTR retrotransposons as molecular markers in plants. Methods Mol Biol 2012; 859:115-153. [PMID: 22367869 DOI: 10.1007/978-1-61779-603-6_7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Retrotransposons are a major agent of genome evolution. Various molecular marker systems have been developed that exploit the ubiquitous nature of these genetic elements and their property of stable integration into dispersed chromosomal loci that are polymorphic within species. The key methods, SSAP, IRAP, REMAP, RBIP, and ISBP, all detect the sites at which the retrotransposon DNA, which is conserved between families of elements, is integrated into the genome. Marker systems exploiting these methods can be easily developed and inexpensively deployed in the absence of extensive genome sequence data. They offer access to the dynamic and polymorphic, nongenic portion of the genome and thereby complement methods, such as gene-derived SNPs, that target primarily the genic fraction.
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Affiliation(s)
- Alan H Schulman
- Plant Genomics, MTT Agrifood Research Finland, Jokioinen, Finland.
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Tomita M, Okutani A, Beiles A, Nevo E. Genomic, RNA, and ecological divergences of the Revolver transposon-like multi-gene family in Triticeae. BMC Evol Biol 2011; 11:269. [PMID: 21943048 PMCID: PMC3203089 DOI: 10.1186/1471-2148-11-269] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 09/25/2011] [Indexed: 12/15/2022] Open
Abstract
Background Revolver is a newly discovered multi-gene family of transposable elements in the Triticeae genome. Revolver encompasses 2929 to 3041 bp, has 20 bp of terminal inverted repeated sequences at both ends, and contains a transcriptionally active gene encoding a DNA-binding-like protein. A putative TATA box is located at base 221, with a cap site at base 261 and a possible polyadenylation signal AATAAA at base 2918. Revolver shows considerable quantitative variation in wheat and its relatives. Results Revolver cDNAs varied between 395 and 2,182 bp in length. The first exon exhibited length variation, but the second and third exons were almost identical. These variants in the Revolver family shared the downstream region of the second intron, but varied structurally at the 5' first exon. There were 58 clones, which showed partial homology to Revolver, among 440,000 expressed sequence tagged (EST) clones sourced from Triticeae. In these Revolver homologues with lengths of 360-744 bp, the portion after the 2nd exon was conserved (65-79% homology), but the 1st exon sequences had mutually low homology, with mutations classified into 12 types, and did not have EST sequences with open reading frames (ORFs). By PCR with the 3'-flanking region of a typical genomic clone of Revolver-2 used as a single primer, rye chromosomes 1R and 5R could be simultaneously identified. Extensive eco-geographic diversity and divergence was observed among 161 genotypes of the single species Triticum dicoccoides collected from 18 populations in Israel with varying exposures to abiotic and biotic stresses (soil, temperature, altitude, water availability, and pathogens). Conclusions On the base of existing differences between Revolver variants, the molecular markers that can distinguish different rye chromosomes were developed. Eco-geographic diversification of wild emmer T. dicoccoides in Israel and high Revolver copy numbers are associated with higher rainfall and biotic stresses. The remarkable quantitative differences among copy numbers of Revolver in the same species from different ecosystems suggest strong amplification activity within the last 10,000 years. It is the interesting finding because the majority of Triticeae high-copy transposable elements seem to be inactive at the recent time except for BARE-1 element in Hordeum and the fact might be interesting to perceive the processes of plant adaptive evolution.
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Affiliation(s)
- Motonori Tomita
- Molecular Genetics Laboratory, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan.
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Bandopadhyay R, Rustgi S, Chaudhuri RK, Khurana P, Khurana JP, Tyagi AK, Balyan HS, Houben A, Gupta PK. Use of methylation filtration and C(0)t fractionation for analysis of genome composition and comparative genomics in bread wheat. J Genet Genomics 2011; 38:315-25. [PMID: 21777856 DOI: 10.1016/j.jgg.2011.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Revised: 06/08/2011] [Accepted: 06/13/2011] [Indexed: 11/16/2022]
Abstract
We investigated the compositional and structural differences in sequences derived from different fractions of wheat genomic DNA obtained using methylation filtration and C(0)t fractionation. Comparative analysis of these sequences revealed large compositional and structural variations in terms of GC content, different structural elements including repeat sequences (e.g., transposable elements and simple sequence repeats), protein coding genes, and non-coding RNA genes. A correlation between methylation status [determined on the basis of selective inclusion/exclusion in methylation-filtered (MF) library] of different repeat elements and expression level was observed. The expression levels were determined by comparing MF sequences with expressed sequence tags (ESTs) available in the public domain. Only a limited overlap among MF, high C(0)t (HC), and ESTs was observed, suggesting that these sequences may largely either represent the low-copy non-transcribed sequences or include genes with low expression levels. Thus, these results indicated a need to study MF and HC sequences along with ESTs to fully appreciate complexity of wheat gene space.
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Affiliation(s)
- Rajib Bandopadhyay
- Department of Genetics & Plant Breeding, Ch. Charan Singh University, Meerut, India
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Okpul T, Harding RM, Dieters MJ, Godwin ID. Occurrence of LINE, gypsy-like, and copia-like retrotransposons in the clonally propagated sweet potato ( Ipomoea batatasL.). Genome 2011; 54:603-9. [DOI: 10.1139/g11-027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retrotransposons are a class of transposable elements that represent a major fraction of the repetitive DNA of most eukaryotes. Their abundance stems from their expansive replication strategies. We screened and isolated sequence fragments of long terminal repeat (LTR), gypsy-like reverse transcriptase (rt) and gypsy-like envelope (env) domains, and two partial sequences of non-LTR retrotransposons, long interspersed element (LINE), in the clonally propagated allohexaploid sweet potato (Ipomoea batatas (L.) Lam.) genome. Using dot-blot hybridization, these elements were found to be present in the ~1597 Mb haploid sweet potato genome with copy numbers ranging from ~50 to ~4100 as observed in the partial LTR (IbLtr-1) and LINE (IbLi-1) sequences, respectively. The continuous clonal propagation of sweet potato may have contributed to such a multitude of copies of some of these genomic elements. Interestingly, the isolated gypsy-like env and gypsy-like rt sequence fragments, IbGy-1 (~2100 copies) and IbGy-2 (~540 copies), respectively, were found to be homologous to the Bagy-2 cDNA sequences of barley (Hordeum vulgare L.). Although the isolated partial sequences were found to be homologous to other transcriptionally active elements, future studies are required to determine whether they represent elements that are transcriptionally active under normal and (or) stressful conditions.
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Affiliation(s)
- Tom Okpul
- The University of Queensland, School of Agriculture and Food Sciences, St. Lucia 4072, QLD, Australia
| | - Robert M. Harding
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Mark J. Dieters
- The University of Queensland, School of Agriculture and Food Sciences, St. Lucia 4072, QLD, Australia
| | - Ian D. Godwin
- The University of Queensland, School of Agriculture and Food Sciences, St. Lucia 4072, QLD, Australia
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Evrensel C, Yilmaz S, Temel A, Gozukirmizi N. Variations in BARE-1 insertion patterns in barley callus cultures. GENETICS AND MOLECULAR RESEARCH 2011; 10:980-7. [PMID: 21710447 DOI: 10.4238/vol10-2gmr965] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The stability of aging barley calli was investigated with the barley retroelement 1 (BARE-1) retrotransposon specific inter-retrotransposon amplified polymorphism (IRAP) technique. Mature embryos of barley (Hordeum vulgare cv. Zafer-160) were cultured on callus induction MS medium supplemented with 3 mg/L 2,4-D and maintained on the same medium for 60 days. Ten IRAP primers were used in 25 different combinations. The similarity index between 30-day-old and 45-day-old calli was 84%; however, the similarity index between mature embryos and 45-day-old calli was 75%. These culture conditions caused BARE-1 retrotransposon alterations to appear as different band profiles. This is the first report of the use of the IRAP technique in barley in an investigation of callus development.
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Affiliation(s)
- C Evrensel
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Vezneciler, Istanbul, Turkey
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Li J, Zhao GH, Li XY, Chen F, Chen JB, Zou FC, Yang JF, Lin RQ, Weng YB, Zhu XQ. IRAP: An efficient retrotransposon-based electrophoretic technique for studying genetic variability among geographical isolates of Schistosoma japonicum. Electrophoresis 2011; 32:1473-9. [PMID: 21626522 DOI: 10.1002/elps.201100044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 03/04/2011] [Accepted: 03/04/2011] [Indexed: 11/12/2022]
Abstract
In the present study, a inter-retrotransposon-amplified polymorphism (IRAP) technique, based on retrotransposons, was used to examine genetic variability among Schistosoma japonicum isolates from different provinces in mainland China. Of the 15 primers screened, 5 produced highly reproducible IRAP patterns. Using these primers, 54 discernible DNA fragments were generated with 40 (74.07%) being polymorphic, indicating considerable genetic variation among the examined S. japonicum isolates. The primer LTR-11 was found to be able to differentiate male and female parasites, producing one constant specific band for female S. japonicum isolates. The percentages of polymorphic bands (PPB) among all parasites, among isolates from mountainous provinces and among those from the lake/marshland areas were 74.07, 48.15, and 66.67%, respectively. UPGMA analysis revealed that the IRAP profiles could group S. japonicum isolates in mainland China into two clades (mountainous and lake/marshland types), and samples from the same geographical origins clustered together. These results demonstrated that the IRAP technique is suitable for studying genetic diversity and population structures, and also provides an effective technique for studying sex differentiation of S. japonicum.
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Affiliation(s)
- Juan Li
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu Province, P R China
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Yaakov B, Kashkush K. Methylation, transcription, and rearrangements of transposable elements in synthetic allopolyploids. INTERNATIONAL JOURNAL OF PLANT GENOMICS 2011; 2011:569826. [PMID: 21760771 PMCID: PMC3134107 DOI: 10.1155/2011/569826] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 03/15/2011] [Indexed: 05/18/2023]
Abstract
Transposable elements (TEs) constitute over 90% of the wheat genome. It was suggested that "genomic stress" such as hybridity or polyploidy might activate transposons. Intensive investigations of various polyploid systems revealed that allopolyploidization event is associated with widespread changes in genome structure, methylation, and expression involving low- and high-copy, coding and noncoding sequences. Massive demethylation and transcriptional activation of TEs were also observed in newly formed allopolyploids. Massive proliferation, however, was reported for very limited number of TE families in various polyploidy systems. The aim of this review is to summarize the accumulated data on genetic and epigenetic dynamics of TEs, particularly in synthetic allotetraploid and allohexaploid wheat species. In addition, the underlying mechanisms and the potential biological significance of TE dynamics following allopolyploidization are discussed.
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Affiliation(s)
- Beery Yaakov
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Khalil Kashkush
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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Lisch D, Slotkin RK. Strategies for silencing and escape: the ancient struggle between transposable elements and their hosts. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 292:119-52. [PMID: 22078960 DOI: 10.1016/b978-0-12-386033-0.00003-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Over the past several years, there has been an explosion in our understanding of the mechanisms by which plant transposable elements (TEs) are epigenetically silenced and maintained in an inactive state over long periods of time. This highly efficient process results in vast numbers of inactive TEs; indeed, the majority of many plant genomes are composed of these quiescent elements. This observation has led to the rather static view that TEs represent an essentially inert portion of plant genomes. However, recent work has demonstrated that TE silencing is a highly dynamic process that often involves transcription of TEs at particular times and places during plant development. Plants appear to use transcripts from silenced TEs as an ongoing source of information concerning the mobile portion of the genome. In contrast to our understanding of silencing pathways, we know relatively little about the ways in which TEs evade silencing. However, vast differences in TE content between even closely related plant species suggest that they are often wildly successful at doing so. Here, we discuss TE activity in plants as the result of a constantly shifting balance between host strategies for TE silencing and TE strategies for escape and amplification.
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Affiliation(s)
- Damon Lisch
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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Abstract
BACKGROUND Mobile genetic elements represent a high proportion of the Eukaryote genomes. In maize, 85% of genome is composed by transposable elements of several families. First step in transposable element life cycle is the synthesis of an RNA, but few is known about the regulation of transcription for most of the maize transposable element families. Maize is the plant from which more ESTs have been sequenced (more than two million) and the third species in total only after human and mice. This allowed us to analyze the transcriptional activity of the maize transposable elements based on EST databases. RESULTS We have investigated the transcriptional activity of 56 families of transposable elements in different maize organs based on the systematic search of more than two million expressed sequence tags. At least 1.5% maize ESTs show sequence similarity with transposable elements. According to these data, the patterns of expression of each transposable element family is variable, even within the same class of elements. In general, transcriptional activity of the gypsy-like retrotransposons is higher compared to other classes. Transcriptional activity of several transposable elements is specially high in shoot apical meristem and sperm cells. Sequence comparisons between genomic and transcribed sequences suggest that only a few copies are transcriptionally active. CONCLUSIONS The use of powerful high-throughput sequencing methodologies allowed us to elucidate the extent and character of repetitive element transcription in maize cells. The finding that some families of transposable elements have a considerable transcriptional activity in some tissues suggests that, either transposition is more frequent than previously expected, or cells can control transposition at a post-transcriptional level.
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