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1.
Nat Commun ; 12(1): 4377, 2021 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-34312382

RESUMO

The origin and dispersal of cultivated and wild mandarin and related citrus are poorly understood. Here, comparative genome analysis of 69 new east Asian genomes and other mainland Asian citrus reveals a previously unrecognized wild sexual species native to the Ryukyu Islands: C. ryukyuensis sp. nov. The taxonomic complexity of east Asian mandarins then collapses to a satisfying simplicity, accounting for tachibana, shiikuwasha, and other traditional Ryukyuan mandarin types as homoploid hybrid species formed by combining C. ryukyuensis with various mainland mandarins. These hybrid species reproduce clonally by apomictic seed, a trait shared with oranges, grapefruits, lemons and many cultivated mandarins. We trace the origin of apomixis alleles in citrus to mangshanyeju wild mandarins, which played a central role in citrus domestication via adaptive wild introgression. Our results provide a coherent biogeographic framework for understanding the diversity and domestication of mandarin-type citrus through speciation, admixture, and rapid diffusion of apomictic reproduction.


Assuntos
Apomixia/genética , Citrus/genética , Frutas/genética , Genoma de Planta/genética , Alelos , Citrus/classificação , Extremo Oriente , Frequência do Gene , Genética Populacional , Genótipo , Geografia , Haplótipos , Hibridização Genética , Filogenia , Especificidade da Espécie
2.
Annu Rev Plant Biol ; 72: 411-435, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-33848428

RESUMO

A pan-genome is the nonredundant collection of genes and/or DNA sequences in a species. Numerous studies have shown that plant pan-genomes are typically much larger than the genome of any individual and that a sizable fraction of the genes in any individual are present in only some genomes. The construction and interpretation of plant pan-genomes are challenging due to the large size and repetitive content of plant genomes. Most pan-genomes are largely focused on nontransposable element protein coding genes because they are more easily analyzed and defined than noncoding and repetitive sequences. Nevertheless, noncoding and repetitive DNA play important roles in determining the phenotype and genome evolution. Fortunately, it is now feasible to make multiple high-quality genomes that can be used to construct high-resolution pan-genomes that capture all the variation. However, assembling, displaying, and interacting with such high-resolution pan-genomes will require the development of new tools.


Assuntos
Genoma de Planta , Genômica
3.
Nature ; 590(7846): 438-444, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33505029

RESUMO

Long-term climate change and periodic environmental extremes threaten food and fuel security1 and global crop productivity2-4. Although molecular and adaptive breeding strategies can buffer the effects of climatic stress and improve crop resilience5, these approaches require sufficient knowledge of the genes that underlie productivity and adaptation6-knowledge that has been limited to a small number of well-studied model systems. Here we present the assembly and annotation of the large and complex genome of the polyploid bioenergy crop switchgrass (Panicum virgatum). Analysis of biomass and survival among 732 resequenced genotypes, which were grown across 10 common gardens that span 1,800 km of latitude, jointly revealed extensive genomic evidence of climate adaptation. Climate-gene-biomass associations were abundant but varied considerably among deeply diverged gene pools. Furthermore, we found that gene flow accelerated climate adaptation during the postglacial colonization of northern habitats through introgression of alleles from a pre-adapted northern gene pool. The polyploid nature of switchgrass also enhanced adaptive potential through the fractionation of gene function, as there was an increased level of heritable genetic diversity on the nondominant subgenome. In addition to investigating patterns of climate adaptation, the genome resources and gene-trait associations developed here provide breeders with the necessary tools to increase switchgrass yield for the sustainable production of bioenergy.


Assuntos
Aclimatação/genética , Biocombustíveis , Genoma de Planta/genética , Genômica , Aquecimento Global , Panicum/genética , Poliploidia , Biomassa , Ecótipo , Evolução Molecular , Fluxo Gênico , Pool Gênico , Introgressão Genética , Anotação de Sequência Molecular , Panicum/classificação , Panicum/crescimento & desenvolvimento , Estados Unidos
4.
Nat Commun ; 11(1): 5442, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33116128

RESUMO

Miscanthus is a perennial wild grass that is of global importance for paper production, roofing, horticultural plantings, and an emerging highly productive temperate biomass crop. We report a chromosome-scale assembly of the paleotetraploid M. sinensis genome, providing a resource for Miscanthus that links its chromosomes to the related diploid Sorghum and complex polyploid sugarcanes. The asymmetric distribution of transposons across the two homoeologous subgenomes proves Miscanthus paleo-allotetraploidy and identifies several balanced reciprocal homoeologous exchanges. Analysis of M. sinensis and M. sacchariflorus populations demonstrates extensive interspecific admixture and hybridization, and documents the origin of the highly productive triploid bioenergy crop M. × giganteus. Transcriptional profiling of leaves, stem, and rhizomes over growing seasons provides insight into rhizome development and nutrient recycling, processes critical for sustainable biomass accumulation in a perennial temperate grass. The Miscanthus genome expands the power of comparative genomics to understand traits of importance to Andropogoneae grasses.


Assuntos
Poaceae/genética , Biomassa , Cromossomos de Plantas/genética , Elementos de DNA Transponíveis , Diploide , Evolução Molecular , Regulação da Expressão Gênica de Plantas , Variação Genética , Genoma de Planta , Genômica , Modelos Genéticos , Filogenia , Poaceae/classificação , Poaceae/crescimento & desenvolvimento , Poliploidia , Saccharum/genética , Estações do Ano , Sorghum/genética
5.
Hortic Res ; 7: 38, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32194974

RESUMO

Huanglongbing (HLB) is a disease that has devastated the Florida citrus industry, threatens the entire U.S. citrus industry, and globally is rapidly spreading. Florida's citrus production is 90% sweet orange, which is quite sensitive to HLB. The heavy reliance on sweet orange for Florida citrus production makes the industry especially vulnerable to diseases that are damaging to this type of citrus. Furthermore, 90% of Florida oranges are used in producing orange juice that is defined by a federal regulation known as the "orange juice standard", specifying that at least 90% of "orange juice" must be derived from Citrus sinensis. Genomic analyses definitively reveal that sweet orange is not a true species, but just one of many introgression hybrids of C. reticulata and C. maxima, with phenotypic diversity resulting from accumulated mutations in this single hybrid, the "sweet orange". No other fruit industry is limited by law to such a narrow genetic base. Fortunately, there are new citrus hybrids displaying reduced sensitivity to HLB, and in some cases they produce juice, alone or in blends, that consumers would recognize as "orange juice". Reconsidering current regulations on orange juice standards may permit use of such hybrids in "orange juice", providing greater latitude for commercialization of these hybrids, leading to higher-quality orange juice and a more sustainable Florida orange juice industry.

6.
Nature ; 554(7692): 311-316, 2018 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-29414943

RESUMO

The genus Citrus, comprising some of the most widely cultivated fruit crops worldwide, includes an uncertain number of species. Here we describe ten natural citrus species, using genomic, phylogenetic and biogeographic analyses of 60 accessions representing diverse citrus germ plasms, and propose that citrus diversified during the late Miocene epoch through a rapid southeast Asian radiation that correlates with a marked weakening of the monsoons. A second radiation enabled by migration across the Wallace line gave rise to the Australian limes in the early Pliocene epoch. Further identification and analyses of hybrids and admixed genomes provides insights into the genealogy of major commercial cultivars of citrus. Among mandarins and sweet orange, we find an extensive network of relatedness that illuminates the domestication of these groups. Widespread pummelo admixture among these mandarins and its correlation with fruit size and acidity suggests a plausible role of pummelo introgression in the selection of palatable mandarins. This work provides a new evolutionary framework for the genus Citrus.


Assuntos
Citrus/classificação , Citrus/genética , Evolução Molecular , Especiação Genética , Genoma de Planta/genética , Genômica , Filogenia , Ásia Sudeste , Biodiversidade , Produção Agrícola/história , Haplótipos/genética , Heterozigoto , História Antiga , Migração Humana , Hibridização Genética
7.
Proc Natl Acad Sci U S A ; 106(40): 17077-82, 2009 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-19805074

RESUMO

Ten complete mammalian genome sequences were compared by using the "feature frequency profile" (FFP) method of alignment-free comparison. This comparison technique reveals that the whole nongenic portion of mammalian genomes contains evolutionary information that is similar to their genic counterparts--the intron and exon regions. We partitioned the complete genomes of mammals (such as human, chimp, horse, and mouse) into their constituent nongenic, intronic, and exonic components. Phylogenic species trees were constructed for each individual component class of genome sequence data as well as the whole genomes by using standard tree-building algorithms with FFP distances. The phylogenies of the whole genomes and each of the component classes (exonic, intronic, and nongenic regions) have similar topologies, within the optimal feature length range, and all agree well with the evolutionary phylogeny based on a recent large dataset, multispecies, and multigene-based alignment. In the strictest sense, the FFP-based trees are genome phylogenies, not species phylogenies. However, the species phylogeny is highly related to the whole-genome phylogeny. Furthermore, our results reveal that the footprints of evolutionary history are spread throughout the entire length of the whole genome of an organism and are not limited to genes, introns, or short, highly conserved, nongenic sequences that can be adversely affected by factors (such as a choice of sequences, homoplasy, and different mutation rates) resulting in inconsistent species phylogenies.


Assuntos
Evolução Molecular , Genoma/genética , Filogenia , Animais , Biologia Computacional/métodos , Éxons , Genômica/métodos , Humanos , Íntrons , Mamíferos/classificação , Mamíferos/genética
8.
Proc Natl Acad Sci U S A ; 106(31): 12826-31, 2009 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-19553209

RESUMO

The vast sequence divergence among different virus groups has presented a great challenge to alignment-based sequence comparison among different virus families. Using an alignment-free comparison method, we construct the whole-proteome phylogeny for a population of viruses from 11 viral families comprising 142 large dsDNA eukaryote viruses. The method is based on the feature frequency profiles (FFP), where the length of the feature (l-mer) is selected to be optimal for phylogenomic inference. We observe that (i) the FFP phylogeny segregates the population into clades, the membership of each has remarkable agreement with current classification by the International Committee on the Taxonomy of Viruses, with one exception that the mimivirus joins the phycodnavirus family; (ii) the FFP tree detects potential evolutionary relationships among some viral families; (iii) the relative position of the 3 herpesvirus subfamilies in the FFP tree differs from gene alignment-based analysis; (iv) the FFP tree suggests the taxonomic positions of certain "unclassified" viruses; and (v) the FFP method identifies candidates for horizontal gene transfer between virus families.


Assuntos
Vírus de DNA/classificação , Filogenia , Proteoma , Baculoviridae/classificação , Vírus de DNA/genética , Transferência Genética Horizontal , Herpesviridae/classificação , Phycodnaviridae/classificação , Poxviridae/classificação , Alinhamento de Sequência
9.
Biophys J ; 96(3): 917-24, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19186130

RESUMO

We report here a multiprotein blind test of a computer method to predict native protein structures based solely on an all-atom physics-based force field. We use the AMBER 96 potential function with an implicit (GB/SA) model of solvation, combined with replica-exchange molecular-dynamics simulations. Coarse conformational sampling is performed using the zipping and assembly method (ZAM), an approach that is designed to mimic the putative physical routes of protein folding. ZAM was applied to the folding of six proteins, from 76 to 112 monomers in length, in CASP7, a community-wide blind test of protein structure prediction. Because these predictions have about the same level of accuracy as typical bioinformatics methods, and do not utilize information from databases of known native structures, this work opens up the possibility of predicting the structures of membrane proteins, synthetic peptides, or other foldable polymers, for which there is little prior knowledge of native structures. This approach may also be useful for predicting physical protein folding routes, non-native conformations, and other physical properties from amino acid sequences.


Assuntos
Modelos Moleculares , Física/métodos , Proteínas/química , Sequência de Aminoácidos , Simulação por Computador , Bases de Dados de Proteínas , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Conformação Proteica , Dobramento de Proteína , Fatores de Tempo
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