Author
Dong Zhang
Other affiliations: University of Georgia, Cornell University
Bio: Dong Zhang is an academic researcher from Plant Genome Mapping Laboratory. The author has contributed to research in topics: Quantitative trait locus & Population. The author has an hindex of 13, co-authored 25 publications receiving 4324 citations. Previous affiliations of Dong Zhang include University of Georgia & Cornell University.
Topics: Quantitative trait locus, Population, Genome, Pseudoknot, Gene mapping
Papers
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TL;DR: A high-quality genome sequence of domesticated tomato is presented, a draft sequence of its closest wild relative, Solanum pimpinellifolium, is compared, and the two tomato genomes are compared to each other and to the potato genome.
Abstract: Tomato (Solanum lycopersicum) is a major crop plant and a model system for fruit development. Solanum is one of the largest angiosperm genera1 and includes annual and perennial plants from diverse habitats. Here we present a high-quality genome sequence of domesticated tomato, a draft sequence of its closest wild relative, Solanum pimpinellifolium2, and compare them to each other and to the potato genome (Solanum tuberosum). The two tomato genomes show only 0.6% nucleotide divergence and signs of recent admixture, but show more than 8% divergence from potato, with nine large and several smaller inversions. In contrast to Arabidopsis, but similar to soybean, tomato and potato small RNAs map predominantly to gene-rich chromosomal regions, including gene promoters. The Solanum lineage has experienced two consecutive genome triplications: one that is ancient and shared with rosids, and a more recent one. These triplications set the stage for the neofunctionalization of genes controlling fruit characteristics, such as colour and fleshiness.
2,687 citations
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Plant Genome Mapping Laboratory1, Iowa State University2, Joint Genome Institute3, Commonwealth Scientific and Industrial Research Organisation4, Mississippi State University5, Brigham Young University6, Agricultural Research Service7, University of Rhode Island8, Federal University of Rio de Janeiro9, J. Craig Venter Institute10, Northeast Normal University11, University of California, Davis12, Bayer13, University of Georgia14, North Carolina State University15, Empresa Brasileira de Pesquisa Agropecuária16, Cotton Incorporated17, National Institute for Biotechnology and Genetic Engineering18, West Virginia State University19, Hebrew University of Jerusalem20, Texas A&M University21, Central Institute for Cotton Research22, Texas Tech University23, Nanjing Agricultural University24
TL;DR: It is shown that an abrupt five- to sixfold ploidy increase approximately 60 million years (Myr) ago, and allopolyploidy reuniting divergent Gossypium genomes approximately 1–2 Myr ago, conferred about 30–36-fold duplication of ancestral angiosperm genes in elite cottons, genetic complexity equalled only by Brassica among sequenced angiosperms.
Abstract: Polyploidy often confers emergent properties, such as the higher fibre productivity and quality of tetraploid cottons than diploid cottons bred for the same environments. Here we show that an abrupt five- to sixfold ploidy increase approximately 60 million years (Myr) ago, and allopolyploidy reuniting divergent Gossypium genomes approximately 1-2 Myr ago, conferred about 30-36-fold duplication of ancestral angiosperm (flowering plant) genes in elite cottons (Gossypium hirsutum and Gossypium barbadense), genetic complexity equalled only by Brassica among sequenced angiosperms. Nascent fibre evolution, before allopolyploidy, is elucidated by comparison of spinnable-fibred Gossypium herbaceum A and non-spinnable Gossypium longicalyx F genomes to one another and the outgroup D genome of non-spinnable Gossypium raimondii. The sequence of a G. hirsutum A(t)D(t) (in which 't' indicates tetraploid) cultivar reveals many non-reciprocal DNA exchanges between subgenomes that may have contributed to phenotypic innovation and/or other emergent properties such as ecological adaptation by polyploids. Most DNA-level novelty in G. hirsutum recombines alleles from the D-genome progenitor native to its New World habitat and the Old World A-genome progenitor in which spinnable fibre evolved. Coordinated expression changes in proximal groups of functionally distinct genes, including a nuclear mitochondrial DNA block, may account for clusters of cotton-fibre quantitative trait loci affecting diverse traits. Opportunities abound for dissecting emergent properties of other polyploids, particularly angiosperms, by comparison to diploid progenitors and outgroups.
1,015 citations
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Crops Research Institute1, Australian Centre for Plant Functional Genomics2, Agriculture and Agri-Food Canada3, Purdue University4, Plant Genome Mapping Laboratory5, Southwest University6, University of York7, Seoul National University8, Southern Cross University9, University of Missouri10, Centre national de la recherche scientifique11, Huazhong Agricultural University12, Hunan Agricultural University13, University of Queensland14, National Research Council15, Central University, India16, Sahmyook University17, King Abdulaziz University18
TL;DR: A draft genome sequence of Brassica oleracea is described, comparing it with that of its sister species B. rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks.
Abstract: Polyploidization has provided much genetic variation for plant adaptive evolution, but the mechanisms by which the molecular evolution of polyploid genomes establishes genetic architecture underlying species differentiation are unclear Brassica is an ideal model to increase knowledge of polyploid evolution Here we describe a draft genome sequence of Brassica oleracea, comparing it with that of its sister species B rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks, asymmetrical amplification of transposable elements, differential gene co-retention for specific pathways and variation in gene expression, including alternative splicing, among a large number of paralogous and orthologous genes Genes related to the production of anticancer phytochemicals and morphological variations illustrate consequences of genome duplication and gene divergence, imparting biochemical and morphological variation to B oleracea This study provides insights into Brassica genome evolution and will underpin research into the many important crops in this genus
884 citations
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TL;DR: The first high-density, gene-based linkage map for A. duranensis was generated that can serve as a reference map for both wild and cultivated Arachis species and will have utility for fine mapping in other peanut species.
Abstract: Cultivated peanut (Arachis hypogaea) is an allotetraploid species whose ancestral genomes are most likely derived from the A-genome species, A. duranensis, and the B-genome species, A. ipaensis. The very recent (several millennia) evolutionary origin of A. hypogaea has imposed a bottleneck for allelic and phenotypic diversity within the cultigen. However, wild diploid relatives are a rich source of alleles that could be used for crop improvement and their simpler genomes can be more easily analyzed while providing insight into the structure of the allotetraploid peanut genome. The objective of this research was to establish a high-density genetic map of the diploid species A. duranensis based on de novo generated EST databases. Arachis duranensis was chosen for mapping because it is the A-genome progenitor of cultivated peanut and also in order to circumvent the confounding effects of gene duplication associated with allopolyploidy in A. hypogaea. More than one million expressed sequence tag (EST) sequences generated from normalized cDNA libraries of A. duranensis were assembled into 81,116 unique transcripts. Mining this dataset, 1236 EST-SNP markers were developed between two A. duranensis accessions, PI 475887 and Grif 15036. An additional 300 SNP markers also were developed from genomic sequences representing conserved legume orthologs. Of the 1536 SNP markers, 1054 were placed on a genetic map. In addition, 598 EST-SSR markers identified in A. hypogaea assemblies were included in the map along with 37 disease resistance gene candidate (RGC) and 35 other previously published markers. In total, 1724 markers spanning 1081.3 cM over 10 linkage groups were mapped. Gene sequences that provided mapped markers were annotated using similarity searches in three different databases, and gene ontology descriptions were determined using the Medicago Gene Atlas and TAIR databases. Synteny analysis between A. duranensis, Medicago and Glycine revealed significant stretches of conserved gene clusters spread across the peanut genome. A higher level of colinearity was detected between A. duranensis and Glycine than with Medicago. The first high-density, gene-based linkage map for A. duranensis was generated that can serve as a reference map for both wild and cultivated Arachis species. The markers developed here are valuable resources for the peanut, and more broadly, to the legume research community. The A-genome map will have utility for fine mapping in other peanut species and has already had application for mapping a nematode resistance gene that was introgressed into A. hypogaea from A. cardenasii.
71 citations
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TL;DR: SSR-based genetic maps from a cross between Miscanthus sacchariflorus Robustus and M. sinensis provide for many early research needs in this emerging crop, but additional markers are also needed to improve map density and to further characterize the structural changes of the Miscanhurst genome since its divergence from sorghum and Saccharum.
Abstract: We present SSR-based genetic maps from a cross between Miscanthus sacchariflorus Robustus and M. sinensis, the progenitors of the promising cellulosic biofuel feedstock Miscanthus × giganteus. cDNA-derived SSR markers were mapped by the two-way pseudo-testcross model due to the high heterozygosity of each parental species. A total of 261 loci were mapped in M. sacchariflorus, spanning 40 linkage groups and 1,998.8 cM, covering an estimated 72.7% of the genome. For M. sinensis, a total of 303 loci were mapped, forming 23 linkage groups and 2,238.3 cM, covering 84.9% of the genome. The use of cDNA-derived SSR loci permitted alignment of the Miscanthus linkage groups to the sorghum chromosomes, revealing a whole genome duplication affecting the Miscanthus lineage after the divergence of subtribes Sorghinae and Saccharinae, as well as traces of the pan-cereal whole genome duplication. While the present maps provide for many early research needs in this emerging crop, additional markers are also needed to improve map density and to further characterize the structural changes of the Miscanthus genome since its divergence from sorghum and Saccharum.
60 citations
Cited by
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University of Évry Val d'Essonne1, Crops Research Institute2, Agriculture and Agri-Food Canada3, J. Craig Venter Institute4, Fujian Agriculture and Forestry University5, Plant Genome Mapping Laboratory6, University of Giessen7, French Alternative Energies and Atomic Energy Commission8, Institut national de la recherche agronomique9, National Research Council10, Australian Centre for Plant Functional Genomics11, University of Cologne12, Purdue University13, University of California, Berkeley14, University of British Columbia15, Fondation Jean Dausset Centre d'Etude du Polymorphisme Humain16, Huazhong Agricultural University17, Hunan Agricultural University18, Chungnam National University19, University of Arizona20, University of York21, University of Missouri22, Southern Cross University23, University of Western Australia24, Centre national de la recherche scientifique25
TL;DR: The polyploid genome of Brassica napus, which originated from a recent combination of two distinct genomes approximately 7500 years ago and gave rise to the crops of rape oilseed, is sequenced.
Abstract: Oilseed rape (Brassica napus L.) was formed ~7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72× genome multiplication since the origin of angiosperms and high gene content. We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement.
1,743 citations
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Academy of Sciences of the Czech Republic1, University of Saskatchewan2, Bayer3, Kansas State University4, University of California, Riverside5, Blaise Pascal University6, Kyoto University7, University of Dundee8, Punjab Agricultural University9, Indian Agricultural Research Institute10, University of Delhi11, University of Tsukuba12, Yokohama City University13, National Research Council14, Norwegian University of Life Sciences15, Sainsbury Laboratory16, Leibniz Association17, United States Department of Energy18, James Hutton Institute19, Institut national de la recherche agronomique20, University of Zurich21, Sabancı University22, Murdoch University23
TL;DR: Insight into the genome biology of a polyploid crop provide a springboard for faster gene isolation, rapid genetic marker development, and precise breeding to meet the needs of increasing food demand worldwide.
Abstract: An ordered draft sequence of the 17-gigabase hexaploid bread wheat (Triticum aestivum) genome has been produced by sequencing isolated chromosome arms. We have annotated 124,201 gene loci distributed nearly evenly across the homeologous chromosomes and subgenomes. Comparative gene analysis of wheat subgenomes and extant diploid and tetraploid wheat relatives showed that high sequence similarity and structural conservation are retained, with limited gene loss, after polyploidization. However, across the genomes there was evidence of dynamic gene gain, loss, and duplication since the divergence of the wheat lineages. A high degree of transcriptional autonomy and no global dominance was found for the subgenomes. These insights into the genome biology of a polyploid crop provide a springboard for faster gene isolation, rapid genetic marker development, and precise breeding to meet the needs of increasing food demand worldwide.
1,421 citations
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TL;DR: Genomic signatures of selection and domestication are associated with positively selected genes (PSGs) for fiber improvement in the A subgenome and for stress tolerance in the D subgenomes, suggesting asymmetric evolution.
Abstract: Upland cotton is a model for polyploid crop domestication and transgenic improvement. Here we sequenced the allotetraploid Gossypium hirsutum L. acc. TM-1 genome by integrating whole-genome shotgun reads, bacterial artificial chromosome (BAC)-end sequences and genotype-by-sequencing genetic maps. We assembled and annotated 32,032 A-subgenome genes and 34,402 D-subgenome genes. Structural rearrangements, gene loss, disrupted genes and sequence divergence were more common in the A subgenome than in the D subgenome, suggesting asymmetric evolution. However, no genome-wide expression dominance was found between the subgenomes. Genomic signatures of selection and domestication are associated with positively selected genes (PSGs) for fiber improvement in the A subgenome and for stress tolerance in the D subgenome. This draft genome sequence provides a resource for engineering superior cotton lines.
1,221 citations
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TL;DR: It is found that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns.
Abstract: Green plants (Viridiplantae) include around 450,000–500,000 species1,2 of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life.
907 citations
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Crops Research Institute1, Australian Centre for Plant Functional Genomics2, Agriculture and Agri-Food Canada3, Purdue University4, Plant Genome Mapping Laboratory5, Southwest University6, University of York7, Seoul National University8, Southern Cross University9, University of Missouri10, Centre national de la recherche scientifique11, Huazhong Agricultural University12, Hunan Agricultural University13, University of Queensland14, National Research Council15, Central University, India16, Sahmyook University17, King Abdulaziz University18
TL;DR: A draft genome sequence of Brassica oleracea is described, comparing it with that of its sister species B. rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks.
Abstract: Polyploidization has provided much genetic variation for plant adaptive evolution, but the mechanisms by which the molecular evolution of polyploid genomes establishes genetic architecture underlying species differentiation are unclear Brassica is an ideal model to increase knowledge of polyploid evolution Here we describe a draft genome sequence of Brassica oleracea, comparing it with that of its sister species B rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks, asymmetrical amplification of transposable elements, differential gene co-retention for specific pathways and variation in gene expression, including alternative splicing, among a large number of paralogous and orthologous genes Genes related to the production of anticancer phytochemicals and morphological variations illustrate consequences of genome duplication and gene divergence, imparting biochemical and morphological variation to B oleracea This study provides insights into Brassica genome evolution and will underpin research into the many important crops in this genus
884 citations