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1.
Gigascience ; 8(10)2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31644802

RESUMO

BACKGROUND: The 1000 Plant transcriptomes initiative (1KP) explored genetic diversity by sequencing RNA from 1,342 samples representing 1,173 species of green plants (Viridiplantae). FINDINGS: This data release accompanies the initiative's final/capstone publication on a set of 3 analyses inferring species trees, whole genome duplications, and gene family expansions. These and previous analyses are based on de novo transcriptome assemblies and related gene predictions. Here, we assess their data and assembly qualities and explain how we detected potential contaminations. CONCLUSIONS: These data will be useful to plant and/or evolutionary scientists with interests in particular gene families, either across the green plant tree of life or in more focused lineages.


Assuntos
Genes de Plantas , Viridiplantae/genética , Proteínas de Plantas/genética , Análise de Sequência de RNA , Transcriptoma
2.
Proc Natl Acad Sci U S A ; 116(11): 5015-5020, 2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30804180

RESUMO

Chloroplast retrograde signaling networks are vital for chloroplast biogenesis, operation, and signaling, including excess light and drought stress signaling. To date, retrograde signaling has been considered in the context of land plant adaptation, but not regarding the origin and evolution of signaling cascades linking chloroplast function to stomatal regulation. We show that key elements of the chloroplast retrograde signaling process, the nucleotide phosphatase (SAL1) and 3'-phosphoadenosine-5'-phosphate (PAP) metabolism, evolved in streptophyte algae-the algal ancestors of land plants. We discover an early evolution of SAL1-PAP chloroplast retrograde signaling in stomatal regulation based on conserved gene and protein structure, function, and enzyme activity and transit peptides of SAL1s in species including flowering plants, the fern Ceratopteris richardii, and the moss Physcomitrella patens Moreover, we demonstrate that PAP regulates stomatal closure via secondary messengers and ion transport in guard cells of these diverse lineages. The origin of stomata facilitated gas exchange in the earliest land plants. Our findings suggest that the conquest of land by plants was enabled by rapid response to drought stress through the deployment of an ancestral SAL1-PAP signaling pathway, intersecting with the core abscisic acid signaling in stomatal guard cells.


Assuntos
Adaptação Fisiológica , Evolução Biológica , Cloroplastos/metabolismo , Transdução de Sinais , Viridiplantae/fisiologia , Difosfato de Adenosina , Embriófitas/fisiologia , Peróxido de Hidrogênio/metabolismo , Transporte de Íons , Movimento , Óxido Nítrico/metabolismo , Filogenia , Estômatos de Plantas/fisiologia
3.
Nat Plants ; 5(1): 63-73, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30626928

RESUMO

We present reference-quality genome assembly and annotation for the stout camphor tree (Cinnamomum kanehirae (Laurales, Lauraceae)), the first sequenced member of the Magnoliidae comprising four orders (Laurales, Magnoliales, Canellales and Piperales) and over 9,000 species. Phylogenomic analysis of 13 representative seed plant genomes indicates that magnoliid and eudicot lineages share more recent common ancestry than monocots. Two whole-genome duplication events were inferred within the magnoliid lineage: one before divergence of Laurales and Magnoliales and the other within the Lauraceae. Small-scale segmental duplications and tandem duplications also contributed to innovation in the evolutionary history of Cinnamomum. For example, expansion of the terpenoid synthase gene subfamilies within the Laurales spawned the diversity of Cinnamomum monoterpenes and sesquiterpenes.


Assuntos
Cinnamomum camphora/genética , Evolução Molecular , Genoma de Planta , Filogenia , Proteínas de Plantas/genética , Alquil e Aril Transferases/genética , Elementos de DNA Transponíveis , Magnoliopsida/genética , Anotação de Sequência Molecular , Família Multigênica , Polimorfismo de Nucleotídeo Único , Sintenia
4.
Syst Biol ; 68(4): 594-606, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30535394

RESUMO

Sequencing of target-enriched libraries is an efficient and cost-effective method for obtaining DNA sequence data from hundreds of nuclear loci for phylogeny reconstruction. Much of the cost of developing targeted sequencing approaches is associated with the generation of preliminary data needed for the identification of orthologous loci for probe design. In plants, identifying orthologous loci has proven difficult due to a large number of whole-genome duplication events, especially in the angiosperms (flowering plants). We used multiple sequence alignments from over 600 angiosperms for 353 putatively single-copy protein-coding genes identified by the One Thousand Plant Transcriptomes Initiative to design a set of targeted sequencing probes for phylogenetic studies of any angiosperm group. To maximize the phylogenetic potential of the probes, while minimizing the cost of production, we introduce a k-medoids clustering approach to identify the minimum number of sequences necessary to represent each coding sequence in the final probe set. Using this method, 5-15 representative sequences were selected per orthologous locus, representing the sequence diversity of angiosperms more efficiently than if probes were designed using available sequenced genomes alone. To test our approximately 80,000 probes, we hybridized libraries from 42 species spanning all higher-order groups of angiosperms, with a focus on taxa not present in the sequence alignments used to design the probes. Out of a possible 353 coding sequences, we recovered an average of 283 per species and at least 100 in all species. Differences among taxa in sequence recovery could not be explained by relatedness to the representative taxa selected for probe design, suggesting that there is no phylogenetic bias in the probe set. Our probe set, which targeted 260 kbp of coding sequence, achieved a median recovery of 137 kbp per taxon in coding regions, a maximum recovery of 250 kbp, and an additional median of 212 kbp per taxon in flanking non-coding regions across all species. These results suggest that the Angiosperms353 probe set described here is effective for any group of flowering plants and would be useful for phylogenetic studies from the species level to higher-order groups, including the entire angiosperm clade itself.


Assuntos
Sondas de DNA , Magnoliopsida/genética , Análise de Sequência de DNA/métodos , Análise por Conglomerados
5.
Genome Res ; 28(9): 1333-1344, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30002159

RESUMO

In grasses, two pathways that generate diverse and numerous 21-nt (premeiotic) and 24-nt (meiotic) phased siRNAs are highly enriched in anthers, the male reproductive organs. These "phasiRNAs" are analogous to mammalian piRNAs, yet their functions and evolutionary origins remain largely unknown. The 24-nt meiotic phasiRNAs have only been described in grasses, wherein their biogenesis is dependent on a specialized Dicer (DCL5). To assess how evolution gave rise to this pathway, we examined reproductive phasiRNA pathways in nongrass monocots: garden asparagus, daylily, and lily. The common ancestors of these species diverged approximately 115-117 million years ago (MYA). We found that premeiotic 21-nt and meiotic 24-nt phasiRNAs were abundant in all three species and displayed spatial localization and temporal dynamics similar to grasses. The miR2275-triggered pathway was also present, yielding 24-nt reproductive phasiRNAs, and thus originated more than 117 MYA. In asparagus, unlike in grasses, these siRNAs are largely derived from inverted repeats (IRs); analyses in lily identified thousands of precursor loci, and many were also predicted to form foldback substrates for Dicer processing. Additionally, reproductive phasiRNAs were present in female reproductive organs and thus may function in both male and female germinal development. These data describe several distinct mechanisms of production for 24-nt meiotic phasiRNAs and provide new insights into the evolution of reproductive phasiRNA pathways in monocots.


Assuntos
Evolução Molecular , Lilianae/genética , Poaceae/genética , RNA Interferente Pequeno/genética , Meiose , Proteínas de Plantas/metabolismo , Ribonuclease III/metabolismo
6.
BMC Plant Biol ; 18(1): 95, 2018 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-29843615

RESUMO

BACKGROUND: Storage roots are an ecologically and agriculturally important plant trait that have evolved numerous times in angiosperms. Storage roots primarily function to store carbohydrates underground as reserves for perennial species. In morning glories, storage roots are well characterized in the crop species sweetpotato, where starch accumulates in storage roots. This starch-storage tissue proliferates, and roots thicken to accommodate the additional tissue. In morning glories, storage roots have evolved numerous times. The primary goal of this study is to understand whether this was through parallel evolution, where species use a common genetic mechanism to achieve storage root formation, or through convergent evolution, where storage roots in distantly related species are formed using a different set of genes. Pairs of species where one forms storage roots and the other does not were sampled from two tribes in the morning glory family, the Ipomoeeae and Merremieae. Root anatomy in storage roots and fine roots was examined. Furthermore, we sequenced total mRNA from storage roots and fine roots in these species and analyzed differential gene expression. RESULTS: Anatomical results reveal that storage roots of species in the Ipomoeeae tribe, such as sweetpotato, accumulate starch similar to species in the Merremieae tribe but differ in vascular tissue organization. In both storage root forming species, more genes were found to be upregulated in storage roots compared to fine roots. Further, we find that fifty-seven orthologous genes were differentially expressed between storage roots and fine roots in both storage root forming species. These genes are primarily involved in starch biosynthesis, regulation of starch biosynthesis, and transcription factor activity. CONCLUSIONS: Taken together, these results demonstrate that storage roots of species from both morning glory tribes are anatomically different but utilize a common core set of genes in storage root formation. This is consistent with a pattern of parallel evolution, thus highlighting the importance of examining anatomy together with gene expression to understand the evolutionary origins of ecologically and economically important plant traits.


Assuntos
Evolução Molecular , Regulação da Expressão Gênica de Plantas , Ipomoea/genética , Transcriptoma , Vias Biossintéticas , Perfilação da Expressão Gênica , Ipomoea/anatomia & histologia , Ipomoea/metabolismo , Ipomoea batatas/anatomia & histologia , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Fenótipo , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , RNA Mensageiro/genética , Amido/biossíntese , Regulação para Cima
7.
Am J Bot ; 105(4): 631-640, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29608785

RESUMO

PREMISE OF THE STUDY: The slipper orchids (Cypripedioideae) are a morphologically distinct subfamily of Orchidaceae. They also have some of the largest genomes in the orchids, which may be due to polyploidy or some other mechanism of genome evolution. We generated 10 transcriptomes and incorporated existing RNA-seq data to infer a multilocus nuclear phylogeny of the Cypripedioideae and to determine whether a whole-genome duplication event (WGD) correlated with the large genome size of this subfamily. Knowing more about timing of ancient polyploidy events can help us understand the evolution of one of the most species-rich plant families. METHODS: Transcriptome data were used to identify low-copy orthologous genes to infer a phylogeny of Orchidaceae and to identify paralogs to place any WGD events on the species tree. KEY RESULTS: Our transcriptome phylogeny confirmed relationships published in previous studies that used fewer markers but incorporated more taxa. We did not find a WGD event at the base of the slipper orchids; however, we did identify one on the Orchidaceae stem lineage. We also confirmed the presence of a previously identified WGD event deeper in the monocot phylogeny. CONCLUSIONS: Although WGD has played a role in the evolution of Orchidaceae, polyploidy does not appear to be responsible for the large genome size of slipper orchids. The conserved set of 775 largely single-copy nuclear genes identified in this study should prove useful in future studies of orchid evolution.


Assuntos
Genoma de Planta/genética , Evolução Biológica , Perfilação da Expressão Gênica , Genes de Plantas/genética , Marcadores Genéticos/genética , Orchidaceae , Filogenia , Poliploidia
8.
Mol Biol Evol ; 35(2): 354-364, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29069493

RESUMO

Even though lateral movements of transposons across families and even phyla within multicellular eukaryotic kingdoms have been found, little is known about transposon transfer between the kingdoms Animalia and Plantae. We discovered a novel non-LTR retrotransposon, AdLINE3, in a wild peanut species. Sequence comparisons and phylogenetic analyses indicated that AdLINE3 is a member of the RTE clade, originally identified in a nematode and rarely reported in plants. We identified RTE elements in 82 plants, spanning angiosperms to algae, including recently active elements in some flowering plants. RTE elements in flowering plants were likely derived from a single family we refer to as An-RTE. Interestingly, An-RTEs show significant DNA sequence identity with non-LTR retroelements from 42 animals belonging to four phyla. Moreover, the sequence identity of RTEs between two arthropods and two plants was higher than that of homologous genes. Phylogenetic and evolutionary analyses of RTEs from both animals and plants suggest that the An-RTE family was likely transferred horizontally into angiosperms from an ancient aphid(s) or ancestral arthropod(s). Notably, some An-RTEs were recruited as coding sequences of functional genes participating in metabolic or other biochemical processes in plants. This is the first potential example of horizontal transfer of transposons between animals and flowering plants. Our findings help to understand exchanges of genetic material between the kingdom Animalia and Plantae and suggest arthropods likely impacted on plant genome evolution.


Assuntos
Arachis/genética , Artrópodes/genética , Transferência Genética Horizontal , Retroelementos , Animais , Sequência de Bases , Genoma de Planta , Filogenia , Homologia de Sequência do Ácido Nucleico
9.
Nat Commun ; 8(1): 1899, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29196618

RESUMO

Crassulacean acid metabolism (CAM) is a water-use efficient adaptation of photosynthesis that has evolved independently many times in diverse lineages of flowering plants. We hypothesize that convergent evolution of protein sequence and temporal gene expression underpins the independent emergences of CAM from C3 photosynthesis. To test this hypothesis, we generate a de novo genome assembly and genome-wide transcript expression data for Kalanchoë fedtschenkoi, an obligate CAM species within the core eudicots with a relatively small genome (~260 Mb). Our comparative analyses identify signatures of convergence in protein sequence and re-scheduling of diel transcript expression of genes involved in nocturnal CO2 fixation, stomatal movement, heat tolerance, circadian clock, and carbohydrate metabolism in K. fedtschenkoi and other CAM species in comparison with non-CAM species. These findings provide new insights into molecular convergence and building blocks of CAM and will facilitate CAM-into-C3 photosynthesis engineering to enhance water-use efficiency in crops.


Assuntos
Ácidos/metabolismo , Evolução Molecular , Genoma de Planta , Kalanchoe/genética , Dióxido de Carbono/metabolismo , Duplicação Gênica , Kalanchoe/classificação , Kalanchoe/metabolismo , Fotossíntese , Filogenia , Plantas/classificação , Plantas/genética , Plantas/metabolismo , Água/metabolismo
10.
Nat Commun ; 8(1): 1279, 2017 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-29093472

RESUMO

Sex chromosomes evolved from autosomes many times across the eukaryote phylogeny. Several models have been proposed to explain this transition, some involving male and female sterility mutations linked in a region of suppressed recombination between X and Y (or Z/W, U/V) chromosomes. Comparative and experimental analysis of a reference genome assembly for a double haploid YY male garden asparagus (Asparagus officinalis L.) individual implicates separate but linked genes as responsible for sex determination. Dioecy has evolved recently within Asparagus and sex chromosomes are cytogenetically identical with the Y, harboring a megabase segment that is missing from the X. We show that deletion of this entire region results in a male-to-female conversion, whereas loss of a single suppressor of female development drives male-to-hermaphrodite conversion. A single copy anther-specific gene with a male sterile Arabidopsis knockout phenotype is also in the Y-specific region, supporting a two-gene model for sex chromosome evolution.


Assuntos
Arabidopsis/genética , Asparagus (Planta)/genética , Cromossomos de Plantas/genética , Cromossomos Sexuais/genética , Processos de Determinação Sexual/genética , Evolução Molecular , Genoma de Planta , Organismos Hermafroditas/genética , Infertilidade das Plantas/genética
11.
BMC Biotechnol ; 16(1): 47, 2016 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-27245738

RESUMO

BACKGROUND: The ATP-binding cassette (ABC) transporter gene superfamily is ubiquitous among extant organisms and prominently represented in plants. ABC transporters act to transport compounds across cellular membranes and are involved in a diverse range of biological processes. Thus, the applicability to biotechnology is vast, including cancer resistance in humans, drug resistance among vertebrates, and herbicide and other xenobiotic resistance in plants. In addition, plants appear to harbor the highest diversity of ABC transporter genes compared with any other group of organisms. This study applied transcriptome analysis to survey the kingdom-wide ABC transporter diversity in plants and suggest biotechnology applications of this diversity. RESULTS: We utilized sequence similarity-based informatics techniques to infer the identity of ABC transporter gene candidates from 1295 phylogenetically-diverse plant transcriptomes. A total of 97,149 putative (approximately 25 % were full-length) ABC transporter gene members were identified; each RNA-Seq library (plant sample) had 88 ± 30 gene members. As expected, simpler organisms, such as algae, had fewer unique members than vascular land plants. Differences were also noted in the richness of certain ABC transporter subfamilies. Land plants had more unique ABCB, ABCC, and ABCG transporter gene members on average (p < 0.005), and green algae, red algae, and bryophytes had significantly more ABCF transporter gene members (p < 0.005). Ferns had significantly fewer ABCA transporter gene members than all other plant groups (p < 0.005). CONCLUSIONS: We present a transcriptomic overview of ABC transporter gene members across all major plant groups. An increase in the number of gene family members present in the ABCB, ABCC, and ABCD transporter subfamilies may indicate an expansion of the ABC transporter superfamily among green land plants, which include all crop species. The striking difference between the number of ABCA subfamily transporter gene members between ferns and other plant taxa is surprising and merits further investigation. Discussed is the potential exploitation of ABC transporters in plant biotechnology, with an emphasis on crops.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Genes de Plantas/genética , Variação Genética/genética , Genoma de Planta/genética , Proteínas de Plantas/genética , Plantas/genética , Biotecnologia/tendências , Mapeamento Cromossômico/métodos , Mineração de Dados/métodos , Bases de Dados de Proteínas , Especificidade da Espécie
12.
Data Brief ; 7: 532-6, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27054154

RESUMO

This data article provides data and supplemental materials referenced in "Nuclear phylogenomics of the palm subfamily Arecoideae (Arecaceae)" (Comer et al., 2016) [1]. Raw sequence reads generated for this study are available through the Sequence Read Archive (SRA Study Accession: SRP061467). An aligned supermatrix of 168 nuclear genes for 35 taxa (34 palms and one outgroup taxon) is provided. Also provided are individual maximum likelihood gene trees used for the coalescent based analyses, output from the maximum parsimony analyses, and two figures.

13.
Genome Biol Evol ; 8(4): 1150-64, 2016 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-26988252

RESUMO

Comparisons of flowering plant genomes reveal multiple rounds of ancient polyploidy characterized by large intragenomic syntenic blocks. Three such whole-genome duplication (WGD) events, designated as rho (ρ), sigma (σ), and tau (τ), have been identified in the genomes of cereal grasses. Precise dating of these WGD events is necessary to investigate how they have influenced diversification rates, evolutionary innovations, and genomic characteristics such as the GC profile of protein-coding sequences. The timing of these events has remained uncertain due to the paucity of monocot genome sequence data outside the grass family (Poaceae). Phylogenomic analysis of protein-coding genes from sequenced genomes and transcriptome assemblies from 35 species, including representatives of all families within the Poales, has resolved the timing of rho and sigma relative to speciation events and placed tau prior to divergence of Asparagales and the commelinids but after divergence with eudicots. Examination of gene family phylogenies indicates that rho occurred just prior to the diversification of Poaceae and sigma occurred before early diversification of Poales lineages but after the Poales-commelinid split. Additional lineage-specific WGD events were identified on the basis of the transcriptome data. Gene families exhibiting high GC content are underrepresented among those with duplicate genes that persisted following these genome duplications. However, genome duplications had little overall influence on lineage-specific changes in the GC content of coding genes. Improved resolution of the timing of WGD events in monocot history provides evidence for the influence of polyploidization on functional evolution and species diversification.


Assuntos
Evolução Molecular , Genoma de Planta , Magnoliopsida/genética , Transcriptoma , Duplicação Gênica , Oryza/genética , Filogenia , Poaceae/genética , Poliploidia , RNA de Plantas/genética , Sorghum/genética
14.
Microbiol Res ; 184: 1-12, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26856448

RESUMO

Sclerotium rolfsii, a destructive soil-borne fungal pathogen causes stem rot of the cultivated peanut, Arachis hypogaea. This study aimed to identify differentially expressed genes associated with peanut resistance and fungal virulence. Four peanut cultivars (A100-32, Georgia Green, GA-07W and York) with increasing resistance levels were inoculated with a virulent S. rolfsii strain to study the early plant-pathogen interaction. 454 sequencing was performed on RNAs from infected tissue collected at 4 days post inoculation, generating 225,793 high-quality reads. Normalized read counts and fold changes were calculated and statistical analysis used to identify differentially expressed genes. Several genes identified as differential in the RNA-seq experiment were selected based on functions of interest and real-time PCR employed to corroborate their differential expression. Expanding the analysis to include all four cultivars revealed a small but interesting set of genes showing colinearity between cultivar resistance and expression levels. This study identified a set of genes possibly related to pathogen response that may be useful marker assisted selection or transgenic disease control strategies. Additionally, a set of differentially expressed genes that have not been functionally characterized in peanut or other plants and warrant additional investigation were identified.


Assuntos
Arachis/microbiologia , Basidiomycota/crescimento & desenvolvimento , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno , Doenças das Plantas/microbiologia , Arachis/imunologia , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Doenças das Plantas/imunologia , Reação em Cadeia da Polimerase em Tempo Real
15.
PLoS One ; 11(1): e0146062, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26731733

RESUMO

Whereas de novo assemblies of RNA-Seq data are being published for a growing number of species across the tree of life, there are currently no broadly accepted methods for evaluating such assemblies. Here we present a detailed comparison of 99 transcriptome assemblies, generated with 6 de novo assemblers including CLC, Trinity, SOAP, Oases, ABySS and NextGENe. Controlled analyses of de novo assemblies for Arabidopsis thaliana and Oryza sativa transcriptomes provide new insights into the strengths and limitations of transcriptome assembly strategies. We find that the leading assemblers generate reassuringly accurate assemblies for the majority of transcripts. At the same time, we find a propensity for assemblers to fail to fully assemble highly expressed genes. Surprisingly, the instance of true chimeric assemblies is very low for all assemblers. Normalized libraries are reduced in highly abundant transcripts, but they also lack 1000s of low abundance transcripts. We conclude that the quality of de novo transcriptome assemblies is best assessed through consideration of a combination of metrics: 1) proportion of reads mapping to an assembly 2) recovery of conserved, widely expressed genes, 3) N50 length statistics, and 4) the total number of unigenes. We provide benchmark Illumina transcriptome data and introduce SCERNA, a broadly applicable modular protocol for de novo assembly improvement. Finally, our de novo assembly of the Arabidopsis leaf transcriptome revealed ~20 putative Arabidopsis genes lacking in the current annotation.


Assuntos
Arabidopsis/genética , Oryza/genética , Transcriptoma , Perfilação da Expressão Gênica , Genoma de Planta , Análise de Sequência de RNA
16.
Mol Phylogenet Evol ; 97: 32-42, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26748268

RESUMO

Palms (Arecaceae) include economically important species such as coconut, date palm, and oil palm. Resolution of the palm phylogeny has been problematic due to rapid diversification and slow rates of molecular evolution. The focus of this study is on relationships of the 14 tribes of subfamily Arecoideae and their inferred ancestral areas. A targeted sequencing approach was used to generate a data set of 168 single/low copy nuclear genes for 34 species representing the Arecoideae tribes and the other palm subfamilies. Species trees from the concatenated and coalescent based analyses recovered largely congruent topologies. Three major tribal clades were recovered: the POS clade (Podococceae, Oranieae, Sclerospermeae), the RRC clade (Roystoneeae, Reinhardtieae, Cocoseae), and the core arecoid clade (Areceae, Euterpeae, Geonomateae, Leopoldinieae, Manicarieae, Pelagodoxeae). Leopoldinieae was sister to the rest of the core arecoids (Geonomateae, Manicarieae+Pelagodoxeae, and Areceae+Euterpeae). The nuclear phylogeny supported a North American origin for subfamily Arecoideae, with most tribal progenitors diversifying within the Americas. The POS clade may have dispersed from the Americas into Africa, with tribe Oranieae subsequently spreading into the Indo-Pacific. Two independent dispersals into the Indo-Pacific were inferred for two tribes within the core arecoids (tribes Areceae and Pelagodoxeae).


Assuntos
Arecaceae/classificação , Arecaceae/genética , Filogenia , África , Núcleo Celular/genética , Evolução Molecular , Oceano Índico , América do Norte , Oceano Pacífico , Filogeografia
17.
New Phytol ; 209(2): 855-70, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26350789

RESUMO

Despite progress based on multilocus, phylogenetic studies of the palms (order Arecales, family Arecaceae), uncertainty remains in resolution/support among major clades and for the placement of the palms among the commelinid monocots. Palms and related commelinids represent a classic case of substitution rate heterogeneity that has not been investigated in the genomic era. To address questions of relationships, support and rate variation among palms and commelinid relatives, 39 plastomes representing the palms and related family Dasypogonaceae were generated via genome skimming and integrated within a monocot-wide matrix for phylogenetic and molecular evolutionary analyses. Support was strong for 'deep' relationships among the commelinid orders, among the five palm subfamilies, and among tribes of the subfamily Coryphoideae. Additionally, there was extreme heterogeneity in the plastid substitution rates across the commelinid orders indicated by model based analyses, with c. 22 rate shifts, and significant departure from a global clock. To date, this study represents the most comprehensively sampled matrix of plastomes assembled for monocot angiosperms, providing genome-scale support for phylogenetic relationships of monocot angiosperms, and lays the phylogenetic groundwork for comparative analyses of the drivers and correlates of such drastic differences in substitution rates across a diverse and significant clade.


Assuntos
Arecaceae/genética , Genomas de Plastídeos , Filogenia , Evolução Molecular , Magnoliopsida/genética , Proteínas de Plantas/genética
18.
Am J Bot ; 102(6): 888-99, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26101415

RESUMO

PREMISE OF THE STUDY: Several studies have incorporated molecular and morphological data to study the phylogeny of the palms (Arecaceae), but some relationships within the family remain ambiguous-particularly those within Arecoideae, the most diverse subfamily including coconut and oil palm. Here, two next-generation, targeted plastid-enrichment methods were compared and used to elucidate Arecoideae phylogeny. METHODS: Next-generation sequencing techniques were used to generate a plastid genome data set. Long range PCR and hybrid gene capture were used to enrich for chloroplast targets. Ten taxa were enriched using both methods for comparison. Chloroplast sequence data were generated for 31 representatives of the 14 Arecoideae tribes and five outgroup taxa. The phylogeny was reconstructed using maximum likelihood, maximum parsimony, and Bayesian analyses. KEY RESULTS: Long range PCR and hybrid gene capture both enriched the plastid genome and provided similar sequencing coverage. Subfamily Arecoideae was resolved as monophyletic with tribe Chamaedoreeae as the earliest-diverging lineage, implying that the development of flowers in triads defines a synapomorphy for the Arecoideae clade excluding Chamaedoreeae. Three major clades within this group were recovered: Roystoneeae/Reinhardtieae/Cocoseae (RRC), Areceae/Euterpeae/Geonomateae/Leopoldinieae/Manicarieae/Pelagodoxeae (core arecoids), and Podococceae/Oranieae/Sclerospermeae (POS). An Areceae + Euterpeae clade was resolved within the core arecoids. The POS clade was sister to a RRC + core arecoids clade, implying a shared ancestral area in South America for these three clades. CONCLUSIONS: The plastome phylogeny recovered here provides robust resolution of previously ambiguous studies and new insights into palm evolution.


Assuntos
Arecaceae/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Plastídeos/genética , Sequência de Bases , Funções Verossimilhança , Filogenia , Reação em Cadeia da Polimerase , Especificidade da Espécie
19.
Plant J ; 82(6): 991-1003, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25939370

RESUMO

Steroid alkaloids have been shown to elicit a wide range of pharmacological effects that include anticancer and antifungal activities. Understanding the biosynthesis of these molecules is essential to bioengineering for sustainable production. Herein, we investigate the biosynthetic pathway to cyclopamine, a steroid alkaloid that shows promising antineoplastic activities. Supply of cyclopamine is limited, as the current source is solely derived from wild collection of the plant Veratrum californicum. To elucidate the early stages of the pathway to cyclopamine, we interrogated a V. californicum RNA-seq dataset using the cyclopamine accumulation profile as a predefined model for gene expression with the pattern-matching algorithm Haystack. Refactoring candidate genes in Sf9 insect cells led to discovery of four enzymes that catalyze the first six steps in steroid alkaloid biosynthesis to produce verazine, a predicted precursor to cyclopamine. Three of the enzymes are cytochromes P450 while the fourth is a γ-aminobutyrate transaminase; together they produce verazine from cholesterol.


Assuntos
Enzimas/metabolismo , Alcaloides de Veratrum/metabolismo , Veratrum/genética , Veratrum/metabolismo , 4-Aminobutirato Transaminase/genética , 4-Aminobutirato Transaminase/metabolismo , Algoritmos , Animais , Vias Biossintéticas , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Enzimas/genética , Perfilação da Expressão Gênica/métodos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Análise de Sequência de RNA/métodos , Células Sf9 , Transcriptoma
20.
Front Plant Sci ; 5: 615, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25429293

RESUMO

Sucrose transporters (SUTs) are essential for the export and efficient movement of sucrose from source leaves to sink organs in plants. The angiosperm SUT family was previously classified into three or four distinct groups, Types I, II (subgroup IIB), and III, with dicot-specific Type I and monocot-specific Type IIB functioning in phloem loading. To shed light on the underlying drivers of SUT evolution, Bayesian phylogenetic inference was undertaken using 41 sequenced plant genomes, including seven basal lineages at key evolutionary junctures. Our analysis supports four phylogenetically and structurally distinct SUT subfamilies, originating from two ancient groups (AG1 and AG2) that diverged early during terrestrial colonization. In both AG1 and AG2, multiple intron acquisition events in the progenitor vascular plant established the gene structures of modern SUTs. Tonoplastic Type III and plasmalemmal Type II represent evolutionarily conserved descendants of AG1 and AG2, respectively. Type I and Type IIB were previously thought to evolve after the dicot-monocot split. We show, however, that divergence of Type I from Type III SUT predated basal angiosperms, likely associated with evolution of vascular cambium and phloem transport. Type I SUT was subsequently lost in monocots along with vascular cambium, and independent evolution of Type IIB coincided with modified monocot vasculature. Both Type I and Type IIB underwent lineage-specific expansion. In multiple unrelated taxa, the newly-derived SUTs exhibit biased expression in reproductive tissues, suggesting a functional link between phloem loading and reproductive fitness. Convergent evolution of Type I and Type IIB for SUT function in phloem loading and reproductive organs supports the idea that differential vascular development in dicots and monocots is a strong driver for SUT family evolution in angiosperms.

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