scholarly journals A phylogenomic analysis of Nepenthes (Nepenthaceae)

2019 ◽  
Author(s):  
Bruce Murphy ◽  
Félix Forest ◽  
Timothy Barraclough ◽  
James Rosindell ◽  
Sidonie Bellot ◽  
...  

AbstractNepenthaceae is one of the largest carnivorous plant families and features ecological and morphological adaptations indicating an impressive adaptive radiation. However, investigation of evolutionary and taxonomic questions is hindered by poor phylogenetic understanding, with previous molecular studies based on limited loci and taxa. We use high-throughput sequencing with a target-capture methodology based on a 353-loci, probe set to recover sequences for 197 samples, representing 151 described or putative Nepenthes species. Phylogenetic analyses were performed using supermatrix and maximum quartet species tree approaches. Our analyses confirm five Western outlier taxa, followed by N. danseri, as successively sister to the remainder of the group. We also find mostly consistent recovery of two major Southeast Asian clades. The first contains common or widespread lowland species plus a Wallacean–New Guinean clade. Within the second clade, sects. Insignes and Tentaculatae are well supported, while geographically defined clades representing Sumatra, Indochina, Peninsular Malaysia, Palawan, Mindanao and Borneo are also consistently recovered. However, we find considerable conflicting signal at the site and locus level, and often unstable backbone relationships. A handful of Bornean taxa are inconsistently placed and require further investigation. We make further suggestions for a modified infra-generic classification of genus Nepenthes.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6864 ◽  
Author(s):  
Marshal Hedin ◽  
Shahan Derkarabetian ◽  
Adan Alfaro ◽  
Martín J. Ramírez ◽  
Jason E. Bond

The atypoid mygalomorphs include spiders from three described families that build a diverse array of entrance web constructs, including funnel-and-sheet webs, purse webs, trapdoors, turrets and silken collars. Molecular phylogenetic analyses have generally supported the monophyly of Atypoidea, but prior studies have not sampled all relevant taxa. Here we generated a dataset of ultraconserved element loci for all described atypoid genera, including taxa (MecicobothriumandHexurella)key to understanding familial monophyly, divergence times, and patterns of entrance web evolution. We show that the conserved regions of the arachnid UCE probe set target exons, such that it should be possible to combine UCE and transcriptome datasets in arachnids. We also show that different UCE probes sometimes target the same protein, and under the matching parameters used here show that UCE alignments sometimes include non-orthologs. Using multiple curated phylogenomic matrices we recover a monophyletic Atypoidea, and reveal that the family Mecicobothriidae comprises four separate and divergent lineages. Fossil-calibrated divergence time analyses suggest ancient Triassic (or older) origins for several relictual atypoid lineages, with late Cretaceous/early Tertiary divergences within some genera indicating a high potential for cryptic species diversity. The ancestral entrance web construct for atypoids, and all mygalomorphs, is reconstructed as a funnel-and-sheet web.



BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yiheng Wang ◽  
Sheng Wang ◽  
Yanlei Liu ◽  
Qingjun Yuan ◽  
Jiahui Sun ◽  
...  

Abstract Background Atractylodes DC is the basic original plant of the widely used herbal medicines “Baizhu” and “Cangzhu” and an endemic genus in East Asia. Species within the genus have minor morphological differences, and the universal DNA barcodes cannot clearly distinguish the systemic relationship or identify the species of the genus. In order to solve these question, we sequenced the chloroplast genomes of all species of Atractylodes using high-throughput sequencing. Results The results indicate that the chloroplast genome of Atractylodes has a typical quadripartite structure and ranges from 152,294 bp (A. carlinoides) to 153,261 bp (A. macrocephala) in size. The genome of all species contains 113 genes, including 79 protein-coding genes, 30 transfer RNA genes and four ribosomal RNA genes. Four hotspots, rpl22-rps19-rpl2, psbM-trnD, trnR-trnT(GGU), and trnT(UGU)-trnL, and a total of 42–47 simple sequence repeats (SSR) were identified as the most promising potentially variable makers for species delimitation and population genetic studies. Phylogenetic analyses of the whole chloroplast genomes indicate that Atractylodes is a clade within the tribe Cynareae; Atractylodes species form a monophyly that clearly reflects the relationship within the genus. Conclusions Our study included investigations of the sequences and structural genomic variations, phylogenetics and mutation dynamics of Atractylodes chloroplast genomes and will facilitate future studies in population genetics, taxonomy and species identification.



2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Minjie Deng ◽  
Yabing Cao ◽  
Zhenli Zhao ◽  
Lu Yang ◽  
Yanfang Zhang ◽  
...  

Understanding the role of miRNAs in regulating the molecular mechanisms responsive to drought stress was studied in Paulownia “yuza 1.” Two small RNA libraries and two degradome libraries were, respectively, constructed and sequenced in order to detect miRNAs and their target genes associated with drought stress. A total of 107 miRNAs and 42 putative target genes were identified in this study. Among them, 77 miRNAs were differentially expressed between drought-treated Paulownia “yuza 1” and the control (60 downregulated and 17 upregulated). The predicted target genes were annotated using the GO, KEGG, and Nr databases. According to the functional classification of the target genes, Paulownia “yuza 1” may respond to drought stress via plant hormone signal transduction, photosynthesis, and osmotic adjustment. Furthermore, the expression levels of seven miRNAs (ptf-miR157b, ptf-miR159b, ptf-miR398a, ptf-miR9726a, ptf-M2153, ptf-M2218, and ptf-M24a) and their corresponding target genes were validated by quantitative real-time PCR. The results provide relevant information for understanding the molecular mechanism of Paulownia resistance to drought and reference data for researching drought resistance of other trees.



Author(s):  
Timothy L Collins ◽  
Jeremy J Bruhl ◽  
Alexander N Schmidt-Lebuhn ◽  
Ian R H Telford ◽  
Rose L Andrew

Abstract Golden everlasting paper daisies (Xerochrysum, Gnaphalieae, Asteraceae) were some of the earliest Australian native plants to be cultivated in Europe. Reputedly a favourite of Napoléon Bonaparte and Empress Joséphine, X. bracteatum is thought to have been introduced to the island of St Helena in the South Atlantic during Napoléon’s exile there. Colourful cultivars were developed in the 1850s, and there is a widely held view that these were produced by crossing Xerochrysum with African or Asian Helichrysum spp. Recent molecular phylogenetic analyses and subtribal classification of Gnaphalieae cast doubt on this idea. Using single-nucleotide polymorphism (SNP) data, we looked for evidence of gene flow between modern cultivars, naturalized paper daisies from St Helena and four Xerochrysum spp. recorded in Europe in the 1800s. There was strong support for gene flow between cultivars and X. macranthum. Paper daisies from St Helena were genotypically congruent with X. bracteatum and showed no indications of ancestry from other species or from the cultivars, consistent with the continuous occurrence of naturalized paper daisies introduced by Joséphine and Napoléon. We also present new evidence for the origin of colourful Xerochrysum cultivars and hybridization of congeners in Europe from Australian collections.



Antibiotics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 22
Author(s):  
Nasim Safaei ◽  
Yvonne Mast ◽  
Michael Steinert ◽  
Katharina Huber ◽  
Boyke Bunk ◽  
...  

Antibiotic producers have mainly been isolated from soil, which often has led to the rediscovery of known compounds. In this study, we identified the freshwater snail Physa acuta as an unexplored source for new antibiotic producers. The bacterial diversity associated with the snail was characterized by a metagenomic approach using cultivation-independent high-throughput sequencing. Although Actinobacteria represented only 2% of the bacterial community, the focus was laid on the isolation of the genus Streptomyces due to its potential to produce antibiotics. Three Streptomyces strains (7NS1, 7NS2 and 7NS3) were isolated from P. acuta, and the antimicrobial activity of the crude extracts were tested against a selection of Gram-positive and Gram-negative bacteria and fungi. 7NS3 showed the strongest activity against Gram-positive bacteria and, thus, was selected for genome sequencing and a phylogenomic analysis. 7NS3 represents a novel Streptomyces species, which was deposited as Streptomyces sp. DSM 110735 at the Leibniz Institute-German Collection of Microorganisms and Cell Cultures (DSMZ). Bioassay-guided high-performance liquid chromatography (HPLC) and high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS) analyses of crude extract fractions resulted in the detection of four compounds, one of which matched the compound characteristics of emycin A, an angucycline-like aromatic polyketide. Genome mining studies based on the whole-genome sequence of 7NS3 resulted in the identification of a gene cluster potentially coding for emycin A biosynthesis. Our study demonstrates that freshwater snails like P. acuta can represent promising reservoirs for the isolation of new antibiotic-producing actinobacterial species.



2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sebastian Racedo ◽  
Ivan Portnoy ◽  
Jorge I. Vélez ◽  
Homero San-Juan-Vergara ◽  
Marco Sanjuan ◽  
...  

Abstract Background High-throughput sequencing enables the analysis of the composition of numerous biological systems, such as microbial communities. The identification of dependencies within these systems requires the analysis and assimilation of the underlying interaction patterns between all the variables that make up that system. However, this task poses a challenge when considering the compositional nature of the data coming from DNA-sequencing experiments because traditional interaction metrics (e.g., correlation) produce unreliable results when analyzing relative fractions instead of absolute abundances. The compositionality-associated challenges extend to the classification task, as it usually involves the characterization of the interactions between the principal descriptive variables of the datasets. The classification of new samples/patients into binary categories corresponding to dissimilar biological settings or phenotypes (e.g., control and cases) could help researchers in the development of treatments/drugs. Results Here, we develop and exemplify a new approach, applicable to compositional data, for the classification of new samples into two groups with different biological settings. We propose a new metric to characterize and quantify the overall correlation structure deviation between these groups and a technique for dimensionality reduction to facilitate graphical representation. We conduct simulation experiments with synthetic data to assess the proposed method’s classification accuracy. Moreover, we illustrate the performance of the proposed approach using Operational Taxonomic Unit (OTU) count tables obtained through 16S rRNA gene sequencing data from two microbiota experiments. Also, compare our method’s performance with that of two state-of-the-art methods. Conclusions Simulation experiments show that our method achieves a classification accuracy equal to or greater than 98% when using synthetic data. Finally, our method outperforms the other classification methods with real datasets from gene sequencing experiments.



2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Marianne Volleth ◽  
Faisal A. A. Khan ◽  
Stefan Müller ◽  
Robert J. Baker ◽  
Daniela Arenas-Viveros ◽  
...  


Author(s):  
Misako Yajima ◽  
Risako Kakuta ◽  
Yutaro Saito ◽  
Shiori Kitaya ◽  
Atsushi Toyoda ◽  
...  

Epstein–Barr virus (EBV) establishes lifelong latent infection in the majority of healthy individuals, while it is a causative agent for various diseases, including some malignancies. Recent high-throughput sequencing results indicate that there are substantial levels of viral genome heterogeneity among different EBV strains. However, the extent of EBV strain variation among asymptomatically infected individuals remains elusive. Here, we present a streamlined experimental strategy to clone and sequence EBV genomes derived from human tonsillar tissues, which are the reservoirs of asymptomatic EBV infection. Complete EBV genome sequences, including those of repetitive regions, were determined for seven tonsil-derived EBV strains. Phylogenetic analyses based on the whole viral genome sequences of worldwide non-tumour-derived EBV strains revealed that Asian EBV strains could be divided into several distinct subgroups. EBV strains derived from nasopharyngeal carcinoma-endemic areas constitute different subgroups from a subgroup of EBV strains from non-endemic areas, including Japan. The results could be consistent with biased regional distribution of EBV-associated diseases depending on the different EBV strains colonizing different regions in Asian countries.



Genome ◽  
2010 ◽  
Vol 53 (3) ◽  
pp. 180-202 ◽  
Author(s):  
Bernard R. Baum ◽  
Tara Edwards ◽  
Douglas A. Johnson

To complete our study of the genus Hordeum and to elaborate a phylogeny of species based upon 5S rDNA sequences, we have cloned and sequenced PCR amplicons from seven American polyploid species to generate 164 new 5S rRNA gene sequences. These sequences were analysed along with the more than 2000 5S rDNA sequences previously generated from the majority of species in Hordeum to provide a comprehensive picture of the distribution (presence or absence) of 5S rDNA unit classes (orthologous groups) in this genus as well as insights into the phylogeny of Hordeum. Testing of substitution models for each unit class based upon the consensus sequences of all the taxa as well as for each unit class within the genus found that the general best fit was TPM3uf+G, from which a maximum-likelihood tree was calculated. A novel application of cophylogenetic analysis, where relationships among unit classes were treated as host–parasite interactions, depicted some significant pair links under tests of randomness indicative of nonrandom codivergence among several unit classes within the same taxon. The previous classification of four genomic groups is reflected in combinations of unit classes, and it is proposed that current taxa developed from ancient diploidized paleopolyploids and that some were subjected to gene loss, i.e., unit class loss. Finally, separate phylogenetic analyses performed for the tetraploid and hexaploid species were used to derive a working model describing the phylogeny of the polyploid taxa from their putative diploid ancestry.



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