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Arvas YE, Marakli S, Kaya Y, Kalendar R. The power of retrotransposons in high-throughput genotyping and sequencing. FRONTIERS IN PLANT SCIENCE 2023; 14:1174339. [PMID: 37180380 PMCID: PMC10167742 DOI: 10.3389/fpls.2023.1174339] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 04/11/2023] [Indexed: 05/16/2023]
Abstract
The use of molecular markers has become an essential part of molecular genetics through their application in numerous fields, which includes identification of genes associated with targeted traits, operation of backcrossing programs, modern plant breeding, genetic characterization, and marker-assisted selection. Transposable elements are a core component of all eukaryotic genomes, making them suitable as molecular markers. Most of the large plant genomes consist primarily of transposable elements; variations in their abundance contribute to most of the variation in genome size. Retrotransposons are widely present throughout plant genomes, and replicative transposition enables them to insert into the genome without removing the original elements. Various applications of molecular markers have been developed that exploit the fact that these genetic elements are present everywhere and their ability to stably integrate into dispersed chromosomal localities that are polymorphic within a species. The ongoing development of molecular marker technologies is directly related to the deployment of high-throughput genotype sequencing platforms, and this research is of considerable significance. In this review, the practical application to molecular markers, which is a use of technology of interspersed repeats in the plant genome were examined using genomic sources from the past to the present. Prospects and possibilities are also presented.
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Affiliation(s)
- Yunus Emre Arvas
- Department of Biology, Faculty of Sciences, Karadeniz Technical University, Trabzon, Türkiye
| | - Sevgi Marakli
- Department of Molecular Biology and Genetics, Faculty of Arts and Sciences, Yildiz Technical University, Istanbul, Türkiye
| | - Yılmaz Kaya
- Agricultural Biotechnology Department, Faculty of Agriculture, Ondokuz Mayıs University, Samsun, Türkiye
- Department of Biology, Faculty of Science, Kyrgyz-Turkish Manas University, Bishkek, Kyrgyzstan
| | - Ruslan Kalendar
- Center for Life Sciences, National Laboratory Astana, Nazarbayev University, Astana, Kazakhstan
- Institute of Biotechnology, Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
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2
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Mokhtar MM, Alsamman AM, El Allali A. PlantLTRdb: An interactive database for 195 plant species LTR-retrotransposons. FRONTIERS IN PLANT SCIENCE 2023; 14:1134627. [PMID: 36950350 PMCID: PMC10025401 DOI: 10.3389/fpls.2023.1134627] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 02/16/2023] [Indexed: 05/29/2023]
Abstract
LTR-retrotransposons (LTR-RTs) are a large group of transposable elements that replicate through an RNA intermediate and alter genome structure. The activities of LTR-RTs in plant genomes provide helpful information about genome evolution and gene function. LTR-RTs near or within genes can directly alter gene function. This work introduces PlantLTRdb, an intact LTR-RT database for 195 plant species. Using homology- and de novo structure-based methods, a total of 150.18 Gbp representing 3,079,469 pseudomolecules/scaffolds were analyzed to identify, characterize, annotate LTR-RTs, estimate insertion ages, detect LTR-RT-gene chimeras, and determine nearby genes. Accordingly, 520,194 intact LTR-RTs were discovered, including 29,462 autonomous and 490,732 nonautonomous LTR-RTs. The autonomous LTR-RTs included 10,286 Gypsy and 19,176 Copia, while the nonautonomous were divided into 224,906 Gypsy, 218,414 Copia, 1,768 BARE-2, 3,147 TR-GAG and 4,2497 unknown. Analysis of the identified LTR-RTs located within genes showed that a total of 36,236 LTR-RTs were LTR-RT-gene chimeras and 11,619 LTR-RTs were within pseudo-genes. In addition, 50,026 genes are within 1 kbp of LTR-RTs, and 250,587 had a distance of 1 to 10 kbp from LTR-RTs. PlantLTRdb allows researchers to search, visualize, BLAST and analyze plant LTR-RTs. PlantLTRdb can contribute to the understanding of structural variations, genome organization, functional genomics, and the development of LTR-RT target markers for molecular plant breeding. PlantLTRdb is available at https://bioinformatics.um6p.ma/PlantLTRdb.
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3
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Wang L, Zhu T, Rodriguez JC, Deal KR, Dubcovsky J, McGuire PE, Lux T, Spannagl M, Mayer KFX, Baldrich P, Meyers BC, Huo N, Gu YQ, Zhou H, Devos KM, Bennetzen JL, Unver T, Budak H, Gulick PJ, Galiba G, Kalapos B, Nelson DR, Li P, You FM, Luo MC, Dvorak J. Aegilops tauschii genome assembly Aet v5.0 features greater sequence contiguity and improved annotation. G3-GENES GENOMES GENETICS 2021; 11:6369516. [PMID: 34515796 PMCID: PMC8664484 DOI: 10.1093/g3journal/jkab325] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/31/2021] [Indexed: 01/01/2023]
Abstract
Aegilops tauschii is the donor of the D subgenome of hexaploid wheat and an important genetic resource. The reference-quality genome sequence Aet v4.0 for Ae. tauschii acc. AL8/78 was therefore an important milestone for wheat biology and breeding. Further advances in sequencing acc. AL8/78 and release of the Aet v5.0 sequence assembly are reported here. Two new optical maps were constructed and used in the revision of pseudomolecules. Gaps were closed with Pacific Biosciences long-read contigs, decreasing the gap number by 38,899. Transposable elements and protein-coding genes were reannotated. The number of annotated high-confidence genes was reduced from 39,635 in Aet v4.0 to 32,885 in Aet v5.0. A total of 2245 biologically important genes, including those affecting plant phenology, grain quality, and tolerance of abiotic stresses in wheat, was manually annotated and disease-resistance genes were annotated by a dedicated pipeline. Disease-resistance genes encoding nucleotide-binding site domains, receptor-like protein kinases, and receptor-like proteins were preferentially located in distal chromosome regions, whereas those encoding transmembrane coiled-coil proteins were dispersed more evenly along the chromosomes. Discovery, annotation, and expression analyses of microRNA (miRNA) precursors, mature miRNAs, and phasiRNAs are reported, including miRNA target genes. Other small RNAs, such as hc-siRNAs and tRFs, were characterized. These advances enhance the utility of the Ae. tauschii genome sequence for wheat genetics, biotechnology, and breeding.
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Affiliation(s)
- Le Wang
- Department of Plant Sciences, University of California, Davis, Davis, California 95616, USA
| | - Tingting Zhu
- Department of Plant Sciences, University of California, Davis, Davis, California 95616, USA
| | - Juan C Rodriguez
- Department of Plant Sciences, University of California, Davis, Davis, California 95616, USA
| | - Karin R Deal
- Department of Plant Sciences, University of California, Davis, Davis, California 95616, USA
| | - Jorge Dubcovsky
- Department of Plant Sciences, University of California, Davis, Davis, California 95616, USA
| | - Patrick E McGuire
- Department of Plant Sciences, University of California, Davis, Davis, California 95616, USA
| | - Thomas Lux
- Plant Genome and Systems Biology, Helmholtz Zentrum München, Munich 85764, Germany
| | - Manuel Spannagl
- Plant Genome and Systems Biology, Helmholtz Zentrum München, Munich 85764, Germany
| | - Klaus F X Mayer
- Plant Genome and Systems Biology, Helmholtz Zentrum München, Munich 85764, Germany
| | - Patricia Baldrich
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA.,University of Missouri, Columbia, Division of Plant Sciences, Columbia, Missouri 65211, USA
| | - Naxin Huo
- Crop Improvement and Genetics Research Unit, USDA-ARS, Albany, California 94710, USA
| | - Yong Q Gu
- Crop Improvement and Genetics Research Unit, USDA-ARS, Albany, California 94710, USA
| | - Hongye Zhou
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602, USA
| | - Katrien M Devos
- Institute of Plant Breeding, Genetics and Genomics (Dept. of Crop & Soil Sciences) and Dept. of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
| | | | - Turgay Unver
- Ficus Biotechnology, Ostim Teknopark, Ankara 06374, Turkey
| | - Hikmet Budak
- Montana BioAg Inc., Missoula, Montana 59801, USA
| | - Patrick J Gulick
- Department of Biology, Concordia University, Montreal, Quebec H3G 1M8, Canada
| | - Gabor Galiba
- Department of Biological Resources, Centre for Agricultural Research, Eötvös Loránd Research Network, H-2462 Martonvásár, Hungary.,Department of Environmental Sustainability, IES, Hungarian University of Agriculture and Life Sciences, H-8360 Keszthely, Hungary
| | - Balázs Kalapos
- Department of Biological Resources, Centre for Agricultural Research, Eötvös Loránd Research Network, H-2462 Martonvásár, Hungary
| | - David R Nelson
- University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
| | - Pingchuan Li
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario K1A 0C5, Canada
| | - Frank M You
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario K1A 0C5, Canada
| | - Ming-Cheng Luo
- Department of Plant Sciences, University of California, Davis, Davis, California 95616, USA
| | - Jan Dvorak
- Department of Plant Sciences, University of California, Davis, Davis, California 95616, USA
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Flavell RB. Perspective: 50 years of plant chromosome biology. PLANT PHYSIOLOGY 2021; 185:731-753. [PMID: 33604616 PMCID: PMC8133586 DOI: 10.1093/plphys/kiaa108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
The past 50 years has been the greatest era of plant science discovery, and most of the discoveries have emerged from or been facilitated by our knowledge of plant chromosomes. At last we have descriptive and mechanistic outlines of the information in chromosomes that programs plant life. We had almost no such information 50 years ago when few had isolated DNA from any plant species. The important features of genes have been revealed through whole genome comparative genomics and testing of variants using transgenesis. Progress has been enabled by the development of technologies that had to be invented and then become widely available. Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) have played extraordinary roles as model species. Unexpected evolutionary dramas were uncovered when learning that chromosomes have to manage constantly the vast numbers of potentially mutagenic families of transposons and other repeated sequences. The chromatin-based transcriptional and epigenetic mechanisms that co-evolved to manage the evolutionary drama as well as gene expression and 3-D nuclear architecture have been elucidated these past 20 years. This perspective traces some of the major developments with which I have become particularly familiar while seeking ways to improve crop plants. I draw some conclusions from this look-back over 50 years during which the scientific community has (i) exposed how chromosomes guard, readout, control, recombine, and transmit information that programs plant species, large and small, weed and crop, and (ii) modified the information in chromosomes for the purposes of genetic, physiological, and developmental analyses and plant improvement.
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Affiliation(s)
- Richard B Flavell
- International Wheat Yield Partnership, 1500 Research Parkway, College Station, TX 77843, USA
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5
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Stritt C, Wyler M, Gimmi EL, Pippel M, Roulin AC. Diversity, dynamics and effects of long terminal repeat retrotransposons in the model grass Brachypodium distachyon. THE NEW PHYTOLOGIST 2020; 227:1736-1748. [PMID: 31677277 PMCID: PMC7497039 DOI: 10.1111/nph.16308] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/10/2019] [Indexed: 05/13/2023]
Abstract
Transposable elements (TEs) are the main reason for the high plasticity of plant genomes, where they occur as communities of diverse evolutionary lineages. Because research has typically focused on single abundant families or summarized TEs at a coarse taxonomic level, our knowledge about how these lineages differ in their effects on genome evolution is still rudimentary. Here we investigate the community composition and dynamics of 32 long terminal repeat retrotransposon (LTR-RT) families in the 272-Mb genome of the Mediterranean grass Brachypodium distachyon. We find that much of the recent transpositional activity in the B. distachyon genome is due to centromeric Gypsy families and Copia elements belonging to the Angela lineage. With a half-life as low as 66 kyr, the latter are the most dynamic part of the genome and an important source of within-species polymorphisms. Second, GC-rich Gypsy elements of the Retand lineage are the most abundant TEs in the genome. Their presence explains > 20% of the genome-wide variation in GC content and is associated with higher methylation levels. Our study shows how individual TE lineages change the genetic and epigenetic constitution of the host beyond simple changes in genome size.
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Affiliation(s)
- Christoph Stritt
- Institute for Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107Zurich8008Switzerland
| | - Michele Wyler
- Institute for Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107Zurich8008Switzerland
| | - Elena L. Gimmi
- Institute for Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107Zurich8008Switzerland
| | - Martin Pippel
- Max Planck Institute of Molecular Cell Biology and GeneticsPfotenhauerstrasse 108Dresden01307Germany
| | - Anne C. Roulin
- Institute for Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107Zurich8008Switzerland
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6
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Wang B, Liang X, Gleason ML, Hsiang T, Zhang R, Sun G. A chromosome-scale assembly of the smallest Dothideomycete genome reveals a unique genome compaction mechanism in filamentous fungi. BMC Genomics 2020; 21:321. [PMID: 32326892 PMCID: PMC7181583 DOI: 10.1186/s12864-020-6732-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/14/2020] [Indexed: 11/19/2022] Open
Abstract
Background The wide variation in the size of fungal genomes is well known, but the reasons for this size variation are less certain. Here, we present a chromosome-scale assembly of ectophytic Peltaster fructicola, a surface-dwelling extremophile, based on long-read DNA sequencing technology, to assess possible mechanisms associated with genome compaction. Results At 18.99 million bases (Mb), P. fructicola possesses one of the smallest known genomes sequence among filamentous fungi. The genome is highly compact relative to other fungi, with substantial reductions in repeat content, ribosomal DNA copies, tRNA gene quantity, and intron sizes, as well as intergenic lengths and the size of gene families. Transposons take up just 0.05% of the entire genome, and no full-length transposon was found. We concluded that reduced genome sizes in filamentous fungi such as P. fructicola, Taphrina deformans and Pneumocystis jirovecii occurred through reduction in ribosomal DNA copy number and reduced intron sizes. These dual mechanisms contrast with genome reduction in the yeast fungus Saccharomyces cerevisiae, whose small and compact genome is associated solely with intron loss. Conclusions Our results reveal a unique genomic compaction architecture of filamentous fungi inhabiting plant surfaces, and broaden the understanding of the mechanisms associated with compaction of fungal genomes.
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Affiliation(s)
- Bo Wang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi Province, China.,MOE Key Laboratory for Intelligent Networks & Network Security, Faculty of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Xiaofei Liang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi Province, China.
| | - Mark L Gleason
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011, USA
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Rong Zhang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi Province, China
| | - Guangyu Sun
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi Province, China.
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7
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Borredá C, Pérez-Román E, Ibanez V, Terol J, Talon M. Reprogramming of Retrotransposon Activity during Speciation of the Genus Citrus. Genome Biol Evol 2020; 11:3478-3495. [PMID: 31710678 PMCID: PMC7145672 DOI: 10.1093/gbe/evz246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2019] [Indexed: 12/13/2022] Open
Abstract
Speciation of the genus Citrus from a common ancestor has recently been established to begin ∼8 Ma during the late Miocene, a period of major climatic alterations. Here, we report the changes in activity of Citrus LTR retrotransposons during the process of diversification that gave rise to the current Citrus species. To reach this goal, we analyzed four pure species that diverged early during Citrus speciation, three recent admixtures derived from those species and an outgroup of the Citrus clade. More than 30,000 retrotransposons were grouped in ten linages. Estimations of LTR insertion times revealed that retrotransposon activity followed a species-specific pattern of change that could be ascribed to one of three different models. In some genomes, the expected pattern of gradual transposon accumulation was suddenly arrested during the radiation of the ancestor that gave birth to the current Citrus species. The individualized analyses of retrotransposon lineages showed that in each and every species studied, not all lineages follow the general pattern of the species itself. For instance, in most of the genomes, the retrotransposon activity of elements from the SIRE lineage reached its highest level just before Citrus speciation, while for Retrofit elements, it has been steadily growing. Based on these observations, we propose that Citrus retrotransposons may respond to stressful conditions driving speciation as a part of the genetic response involved in adaptation. This proposal implies that the evolving conditions of each species interact with the internal regulatory mechanisms of the genome controlling the proliferation of mobile elements.
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Affiliation(s)
- Carles Borredá
- Centro de Genómica, Instituto Valenciano de Investigaciones Agrarias (IVIA), Valencia, Spain
| | - Estela Pérez-Román
- Centro de Genómica, Instituto Valenciano de Investigaciones Agrarias (IVIA), Valencia, Spain
| | - Victoria Ibanez
- Centro de Genómica, Instituto Valenciano de Investigaciones Agrarias (IVIA), Valencia, Spain
| | - Javier Terol
- Centro de Genómica, Instituto Valenciano de Investigaciones Agrarias (IVIA), Valencia, Spain
| | - Manuel Talon
- Centro de Genómica, Instituto Valenciano de Investigaciones Agrarias (IVIA), Valencia, Spain
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Akakpo R, Carpentier MC, Ie Hsing Y, Panaud O. The impact of transposable elements on the structure, evolution and function of the rice genome. THE NEW PHYTOLOGIST 2020; 226:44-49. [PMID: 31797393 DOI: 10.1111/nph.16356] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
Transposable elements (TEs) are ubiquitous in plants and are the primary genomic component of the majority of taxa. Knowledge of their impact on the structure, function and evolution of plant genomes is therefore a priority in the field of genomics. Rice, as one of the most prevalent crops for food security worldwide, has been subjected to intense research efforts over recent decades. Consequently, a considerable amount of genomic resources has been generated and made freely available to the scientific community. These can be exploited both to improve our understanding of some basic aspects of genome biology of this species and to develop new concepts for crop improvement. In this review, we describe the current knowledge on how TEs have shaped rice chromosomes and propose a new strategy based on a genome-wide association study (GWAS) to address the important question of their functional impact on this crop.
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Affiliation(s)
- Roland Akakpo
- Laboratoire Génome et Développement des Plantes, UMR 5096 CNRS/UPVD, Université de Perpignan, Via Domitia, 52 Avenue Paul Alduy, 66860, Perpignan Cedex, France
| | - Marie-Christine Carpentier
- Laboratoire Génome et Développement des Plantes, UMR 5096 CNRS/UPVD, Université de Perpignan, Via Domitia, 52 Avenue Paul Alduy, 66860, Perpignan Cedex, France
| | - Yue Ie Hsing
- Institute of Plant and Microbial Biology, Acadeia Sinica, 128, Section 2, Yien-chu-yuan Road, Nankang, 115, Taipei, Taiwan
| | - Olivier Panaud
- Laboratoire Génome et Développement des Plantes, UMR 5096 CNRS/UPVD, Université de Perpignan, Via Domitia, 52 Avenue Paul Alduy, 66860, Perpignan Cedex, France
- Institut Universitaire de France, 1 Rue Descartes, 75231, Paris Cedex 05, France
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9
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Zhang X, Qi Y. The Landscape of Copia and Gypsy Retrotransposon During Maize Domestication and Improvement. FRONTIERS IN PLANT SCIENCE 2019; 10:1533. [PMID: 31921227 PMCID: PMC6930232 DOI: 10.3389/fpls.2019.01533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 11/01/2019] [Indexed: 06/10/2023]
Abstract
The release of genomic sequences in the maize HapMap3 population provides an opportunity to study the genetic diversity of maize. In this study, retrotransposon insertion polymorphisms (RIPs) were mapped against the maize genome sequence. In total, 27 retrotransposon families were identified, and more than 170,000 RIPs were discovered in teosinte, landrace, and improved groups. Interestingly, the copy number of transposable elements (TEs) were more abundant in landrace groups than in teosinte or improved groups, suggesting that TEs experienced amplification during domestication and contraction during improvement. Landrace accessions exhibited higher TE insertion frequency compared to the other groups. Furthermore, the position of TE insertions were closer to genes and more abundant in the centromeres of landrace groups compared to the other groups. The three groups could be clearly distinguished by RIPs. These results demonstrate that TEs were amplified and contracted during maize domestication and improvement, respectively.
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10
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Xu J, Dai X, Ramasamy RK, Wang L, Zhu T, McGuire PE, Jorgensen CM, Dehghani H, Gulick PJ, Luo MC, Müller HG, Dvorak J. Aegilops tauschii Genome Sequence: A Framework for Meta-analysis of Wheat QTLs. G3 (BETHESDA, MD.) 2019; 9:841-853. [PMID: 30670607 PMCID: PMC6404623 DOI: 10.1534/g3.118.200921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/12/2019] [Indexed: 12/22/2022]
Abstract
Numerous quantitative trait loci (QTL) have been mapped in tetraploid and hexaploid wheat and wheat relatives, mostly with simple sequence repeat (SSR) or single nucleotide polymorphism (SNP) markers. To conduct meta-analysis of QTL requires projecting them onto a common genomic framework, either a consensus genetic map or genomic sequence. The latter strategy is pursued here. Of 774 QTL mapped in wheat and wheat relatives found in the literature, 585 (75.6%) were successfully projected onto the Aegilops tauschii pseudomolecules. QTL mapped with SNP markers were more successfully projected (92.2%) than those mapped with SSR markers (66.2%). The QTL were not distributed homogeneously along chromosome arms. Their frequencies increased in the proximal-to-distal direction but declined in the most distal regions and were weakly correlated with recombination rates along the chromosome arms. Databases for projected SSR markers and QTL were constructed and incorporated into the Ae. tauschii JBrowse. To facilitate meta-QTL analysis, eight clusters of QTL were used to estimate standard deviations ([Formula: see text]) of independently mapped QTL projected onto the Ae. tauschii genome sequence. The standard deviations [Formula: see text] were modeled as an exponential decay function of recombination rates along the Ae. tauschii chromosomes. We implemented four hypothesis tests for determining the membership of query QTL. The hypothesis tests and estimation procedure for [Formula: see text] were implemented in a web portal for meta-analysis of projected QTL. Twenty-one QTL for Fusarium head blight resistance mapped on wheat chromosomes 3A, 3B, and 3D were analyzed to illustrate the use of the portal for meta-QTL analyses.
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Affiliation(s)
- Jiale Xu
- Department of Plant Sciences, University of California, Davis, California
| | - Xiongtao Dai
- Department of Statistics, Iowa State University, Iowa
| | - Ramesh K Ramasamy
- Department of Plant Sciences, University of California, Davis, California
| | - Le Wang
- Department of Plant Sciences, University of California, Davis, California
| | - Tingting Zhu
- Department of Plant Sciences, University of California, Davis, California
| | - Patrick E McGuire
- Department of Plant Sciences, University of California, Davis, California
| | - Chad M Jorgensen
- Department of Plant Sciences, University of California, Davis, California
| | - Hamid Dehghani
- Department of Plant Sciences, University of California, Davis, California
- Department of Plant Breeding, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran, and
| | - Patrick J Gulick
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Ming-Cheng Luo
- Department of Plant Sciences, University of California, Davis, California
| | - Hans-Georg Müller
- Department of Statistics, University of California, Davis, California
| | - Jan Dvorak
- Department of Plant Sciences, University of California, Davis, California,
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