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April 21, 2020

ASA3P: An automatic and scalable pipeline for the assembly, annotation and higher level analysis of closely related bacterial isolates

Whole genome sequencing of bacteria has become daily routine in many fields. Advances in DNA sequencing technologies and continuously dropping costs have resulted in a tremendous increase in the amounts of available sequence data. However, comprehensive in-depth analysis of the resulting data remains an arduous and time consuming task. In order to keep pace with these promising but challenging developments and to transform raw data into valuable information, standardized analyses and scalable software tools are needed. Here, we introduce ASA3P, a fully automatic, locally executable and scalable assembly, annotation and analysis pipeline for bacterial genomes. The pipeline automatically executes necessary data processing steps, i.e. quality clipping and assembly of raw sequencing reads, scaffolding of contigs and annotation of the resulting genome sequences. Furthermore, ASA3P conducts comprehensive genome characterizations and analyses, e.g. taxonomic classification, detection of antibiotic resistance genes and identification of virulence factors. All results are presented via an HTML5 user interface providing aggregated information, interactive visualizations and access to intermediate results in standard bioinformatics file formats. We distribute ASA3P in two versions: a locally executable Docker container for small-to-medium-scale projects and an OpenStack based cloud computing version able to automatically create and manage self-scaling compute clusters. Thus, automatic and standardized analysis of hundreds of bacterial genomes becomes feasible within hours. The software and further information is available at: http://asap.computational.bio.


April 21, 2020

Whole-genome sequence of Arthrinium phaeospermum, a globally distributed pathogenic fungus.

Arthrinium phaeospermum (Corda) M.B. Ellis is a globally distributed pathogenic fungus with a wide host range; its hosts include not only plants, but also humans and animals. This study aimed to develop genomic resources for A. phaeospermum to provide solid data and a theoretical basis for further studies of its pathogenesis, transcriptomics, proteomics, metabolomics and RNA genomics. The genome was obtained from the mycelia of the strain AP-Z13 using a combination of analyses with the high-throughput Illumina HiSeq 4000 system and PacBio RSII LongRead sequencing platform. Functional annotation was performed by BLASTing protein sequences against those in different publicly available databases to obtain their corresponding annotations. The genome is 48.45?Mb in size, with an N90 scaffold size of 1,931,147?bp, and encodes 19,836 putative predicted genes. This is the first report of the genome-scale assembly and annotation for A. phaeospermum, the first species in the genus Arthrinium to be subjected to whole genome sequencing. Copyright © 2019 Elsevier Inc. All rights reserved.


April 21, 2020

Rational development of transformation in Clostridium thermocellum ATCC 27405 via complete methylome analysis and evasion of native restriction-modification systems.

A major barrier to both metabolic engineering and fundamental biological studies is the lack of genetic tools in most microorganisms. One example is Clostridium thermocellum ATCC 27405T, where genetic tools are not available to help validate decades of hypotheses. A significant barrier to DNA transformation is restriction-modification systems, which defend against foreign DNA methylated differently than the host. To determine the active restriction-modification systems in this strain, we performed complete methylome analysis via single-molecule, real-time sequencing to detect 6-methyladenine and 4-methylcytosine and the rarely used whole-genome bisulfite sequencing to detect 5-methylcytosine. Multiple active systems were identified, and corresponding DNA methyltransferases were expressed from the Escherichia coli chromosome to mimic the C. thermocellum methylome. Plasmid methylation was experimentally validated and successfully electroporated into C. thermocellum ATCC 27405. This combined approach enabled genetic modification of the C. thermocellum-type strain and acts as a blueprint for transformation of other non-model microorganisms.


April 21, 2020

How Genomics Is Changing What We Know About the Evolution and Genome of Bordetella pertussis.

The evolution of Bordetella pertussis from a common ancestor similar to Bordetella bronchiseptica has occurred through large-scale gene loss, inactivation and rearrangements, largely driven by the spread of insertion sequence element repeats throughout the genome. B. pertussis is widely considered to be monomorphic, and recent evolution of the B. pertussis genome appears to, at least in part, be driven by vaccine-based selection. Given the recent global resurgence of whooping cough despite the wide-spread use of vaccination, a more thorough understanding of B. pertussis genomics could be highly informative. In this chapter we discuss the evolution of B. pertussis, including how vaccination is changing the circulating B. pertussis population at the gene-level, and how new sequencing technologies are revealing previously unknown levels of inter- and intra-strain variation at the genome-level.


April 21, 2020

Early emergence of mcr-1-positive Enterobacteriaceae in gulls from Spain and Portugal.

We tested extended-spectrum ß-lactamase producing bacteria from wild gulls (Larus spp.) sampled in 2009 for the presence of mcr-1. We report the detection of mcr-1 and describe genome characteristics of four Escherichia coli and one Klebsiella pneumoniae isolate from Spain and Portugal that also exhibited colistin resistance. Results represent the earliest evidence for colistin-resistant bacteria in European wildlife.Published 2019. This article is a U.S. Government work and is in the public domain in the USA.


April 21, 2020

Cupriavidus sp. strain Ni-2 resistant to high concentration of nickel and its genes responsible for the tolerance by genome comparison.

The widespread use of metals influenced many researchers to examine the relationship between heavy metal toxicity and bacterial resistance. In this study, we have inoculated heavy metal-contaminated soil from Janghang region of South Korea in the nickel-containing media (20 mM Ni2+) for the enrichment. Among dozens of the colonies acquired from the several transfers and serial dilutions with the same concentrations of Ni, the strain Ni-2 was chosen for further studies. The isolates were identified for their phylogenetic affiliations using 16S rRNA gene analysis. The strain Ni-2 was close to Cupriavidus metallidurans and was found to be resistant to antibiotics of vancomycin, erythromycin, chloramphenicol, ampicillin, gentamicin, streptomycin, and kanamycin by disk diffusion method. Of the isolated strains, Ni-2 was sequenced for the whole genome, since the Ni-resistance seemed to be better than the other strains. From the genome sequence we have found that there was a total of 89 metal-resistance-related genes including 11 Ni-resistance genes, 41 heavy metal (As, Cd, Zn, Hg, Cu, and Co)-resistance genes, 22 cation-efflux genes, 4 metal pumping ATPase genes, and 11 metal transporter genes.


April 21, 2020

Chromosome-level reference genome of X12, a highly virulent race of the soybean cyst nematode Heterodera glycines.

Soybean cyst nematode (SCN, Heterodera glycines) is a major pest of soybean that is spreading across major soybean production regions worldwide. Increased SCN virulence has recently been observed in both the United States and China. However, no study has reported a genome assembly for H. glycines at the chromosome scale. Herein, the first chromosome-level reference genome of X12, an unusual SCN race with high infection ability, is presented. Using whole-genome shotgun (WGS) sequencing, PacBio sequencing, Illumina paired-end sequencing, 10X Genomics linked reads and high-throughput chromatin conformation capture (Hi-C) genome scaffolding techniques, a 141.01-Mb assembled genome was obtained with scaffold and contig N50 sizes of 16.27 Mb and 330.54 kb, respectively. The assembly showed high integrity and quality, with over 90% of Illumina reads mapped to the genome. The assembly quality was evaluated using Core Eukaryotic Genes Mapping Approach (CEGMA) and Benchmarking Universal Single-Copy Orthologs (BUSCO). A total of 11,882 genes were predicted using De novo, Homolog and RNAseq data generated from eggs, second-stage juveniles (J2), third-stage juveniles (J3) and fourth-stage juveniles (J4) of X12, and 79.0% of homologous sequences were annotated in the genome. These high-quality X12 genome data will provide valuable resources for research in a broad range of areas, including fundamental nematode biology, SCN-plant interactions and coevolution, and also contribute to the development of technology for overall SCN management. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.


April 21, 2020

Paenibacillus albus sp. nov., a UV radiation-resistant bacterium isolated from soil in Korea.

A novel Gram-stain-positive, motile, white color and endospore-forming bacterium, designated 18JY67-1T, was isolated from soil in Jeju Island, Korea. The strain grow at 15-42 °C (optimum 30 °C) in R2A medium at pH (6.0-9.5) (optimum 7.5). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 18JY67-1T formed a distinct lineage within the family Paenibacillaceae (order Bacillales, class Bacilli), and was closely related to Paenibacillus rhizoryzae (KP675984; 96.9% 16S rRNA gene sequence similarity). The major cellular fatty acids of the strain 18JY67-1T were C16:0 and anteiso-C15:0. The predominant respiratory quinones were MK-7. The major polar lipid was identified as diphosphatidylglycerol. On the basis of phenotypic, chemotaxonomic and genotypic properties clearly indicated that isolate 18JY67-1T represents a novel species within the genus Paenibacillus, for which the name Paenibacillus flavus sp. nov. is proposed. The type strain of Paenibacillus flavus is 18JY67-1T (=?KCTC 33959T =?JCM 33184T).


April 21, 2020

Genome assembly provides insights into the genome evolution and flowering regulation of orchardgrass.

Orchardgrass (Dactylis glomerata L.) is an important forage grass for cultivating livestock worldwide. Here, we report an ~1.84-Gb chromosome-scale diploid genome assembly of orchardgrass, with a contig N50 of 0.93 Mb, a scaffold N50 of 6.08 Mb and a super-scaffold N50 of 252.52 Mb, which is the first chromosome-scale assembled genome of a cool-season forage grass. The genome includes 40 088 protein-coding genes, and 69% of the assembled sequences are transposable elements, with long terminal repeats (LTRs) being the most abundant. The LTRretrotransposons may have been activated and expanded in the grass genome in response to environmental changes during the Pleistocene between 0 and 1 million years ago. Phylogenetic analysis reveals that orchardgrass diverged after rice but before three Triticeae species, and evolutionarily conserved chromosomes were detected by analysing ancient chromosome rearrangements in these grass species. We also resequenced the whole genome of 76 orchardgrass accessions and found that germplasm from Northern Europe and East Asia clustered together, likely due to the exchange of plants along the ‘Silk Road’ or other ancient trade routes connecting the East and West. Last, a combined transcriptome, quantitative genetic and bulk segregant analysis provided insights into the genetic network regulating flowering time in orchardgrass and revealed four main candidate genes controlling this trait. This chromosome-scale genome and the online database of orchardgrass developed here will facilitate the discovery of genes controlling agronomically important traits, stimulate genetic improvement of and functional genetic research on orchardgrass and provide comparative genetic resources for other forage grasses. © 2019 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.


April 21, 2020

Complete genome sequence of Paracoccus sp. Arc7-R13, a silver nanoparticles synthesizing bacterium isolated from Arctic Ocean sediments

Paracoccus sp. Arc7-R13, a silver nanoparticles (AgNPs) synthesizing bacterium, was isolated from Arctic Ocean sediment. Here we describe the complete genome of Paracoccus sp. Arc7-R13. The complete genome contains 4,040,012?bp with 66.66?mol%?G?+?C content, including one circular chromosome of 3,231,929?bp (67.45?mol%?G?+?C content), and eight plasmids with length ranging from 24,536?bp to 199,685?bp. The genome contains 3835 protein-coding genes (CDSs), 49 tRNA genes, as well as 3 rRNA operons as 16S-23S-5S rRNA. Based on the gene annotation and Swiss-Prot analysis, a total of 15 genes belonging to 11 kinds, including silver exporting P-type ATPase (SilP), alkaline phosphatase, nitroreductase, thioredoxin reductase, NADPH dehydrogenase and glutathione peroxidase, might be related to the synthesis of AgNPs. Meanwhile, many additional genes associated with synthesis of AgNPs such as protein-disulfide isomerase, c-type cytochrome, glutathione synthase and dehydrogenase reductase were also identified.


April 21, 2020

Whole genome sequence of first Candida auris strain, isolated in Russia.

Candida auris is an emergent yeast pathogen, easily transmissible between patients and with high percent of multidrug resistant strains. Here we present a draft genome sequence of the first known Russian strain of C. auris, isolated from a case of candidemia. The strain clustered within South Asian C. auris clade and seemingly represented an independent event of dissemination from the original species range. Observed fluconazole resistance was probably due to F105L and K143R mutations in ERG11. © The Author(s) 2019. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.


April 21, 2020

Rapid evolution of a-gliadin gene family revealed by analyzing Gli-2 locus regions of wild emmer wheat.

a-Gliadins are a major group of gluten proteins in wheat flour that contribute to the end-use properties for food processing and contain major immunogenic epitopes that can cause serious health-related issues including celiac disease (CD). a-Gliadins are also the youngest group of gluten proteins and are encoded by a large gene family. The majority of the gene family members evolved independently in the A, B, and D genomes of different wheat species after their separation from a common ancestral species. To gain insights into the origin and evolution of these complex genes, the genomic regions of the Gli-2 loci encoding a-gliadins were characterized from the tetraploid wild emmer, a progenitor of hexaploid bread wheat that contributed the AABB genomes. Genomic sequences of Gli-2 locus regions for the wild emmer A and B genomes were first reconstructed using the genome sequence scaffolds along with optical genome maps. A total of 24 and 16 a-gliadin genes were identified for the A and B genome regions, respectively. a-Gliadin pseudogene frequencies of 86% for the A genome and 69% for the B genome were primarily caused by C to T substitutions in the highly abundant glutamine codons, resulting in the generation of premature stop codons. Comparison with the homologous regions from the hexaploid wheat cv. Chinese Spring indicated considerable sequence divergence of the two A genomes at the genomic level. In comparison, conserved regions between the two B genomes were identified that included a-gliadin pseudogenes containing shared nested TE insertions. Analyses of the genomic organization and phylogenetic tree reconstruction indicate that although orthologous gene pairs derived from speciation were present, large portions of a-gliadin genes were likely derived from differential gene duplications or deletions after the separation of the homologous wheat genomes ~?0.5 MYA. The higher number of full-length intact a-gliadin genes in hexaploid wheat than that in wild emmer suggests that human selection through domestication might have an impact on a-gliadin evolution. Our study provides insights into the rapid and dynamic evolution of genomic regions harboring the a-gliadin genes in wheat.


April 21, 2020

Updated assembly resource of Phytophthora ramorum Pr102 isolate incorporating long reads from PacBio sequencing.

The NA1 clonal lineage of Phytophthora ramorum is responsible for Sudden Oak Death, an epidemic that has devastated California’s coastal forest ecosystems. An NA1 isolate Pr102 derived from coast live oak in California was previously sequenced and reported with 65 Mb assembly containing 12 Mb gaps in 2576 scaffolds. Here we report an improved 70 Mb genome in 1512 scaffolds with 6752 bp gaps after incorporating PacBio P5-C3 longreads. This assembly contains 19494 gene models (average gene length 2515 bp) compared to 16134 genes (average gene length of 1673 bp) in the previous version. We predicted 29 new RXLRs and 76 new paralogs of a total 392 RXLRs from this assembly. We predicted 35 CRNs compared to 19 in earlier version with six paralogs. Our lncRNAs prediction identified 255 candidates. This new resource will be invaluable for future evolution studies on the invasive plant pathogen.


April 21, 2020

Pseudo-chromosome length genome assembly of a double haploid ‘Bartlett’ pear (Pyrus communis L.)

We report an improved assembly and scaffolding of the European pear (Pyrus communis L.) genome (referred to as BartlettDHv2.0), obtained using a combination of Pacific Biosciences RSII Long read sequencing (PacBio), Bionano optical mapping, chromatin interaction capture (Hi-C), and genetic mapping. A total of 496.9 million bases (Mb) corresponding to 97% of the estimated genome size were assembled into 494 scaffolds. Hi-C data and a high-density genetic map allowed us to anchor and orient 87% of the sequence on the 17 chromosomes of the pear genome. About 50% (247 Mb) of the genome consists of repetitive sequences. Comparison with previous assemblies of Pyrus communis. and Pyrus x bretschneideri confirmed the presence of 37,445 protein-coding genes, which is 13% fewer than previously predicted.


April 21, 2020

Comparative Genomic Analysis of Virulence, Antimicrobial Resistance, and Plasmid Profiles of Salmonella Dublin Isolated from Sick Cattle, Retail Beef, and Humans in the United States.

Salmonella enterica serovar Dublin is a host-adapted serotype associated with typhoidal disease in cattle. While rare in humans, it usually causes severe illness, including bacteremia. In the United States, Salmonella Dublin has become one of the most multidrug-resistant (MDR) serotypes. To understand the genetic elements that are associated with virulence and resistance, we sequenced 61 isolates of Salmonella Dublin (49 from sick cattle and 12 from retail beef) using the Illumina MiSeq and closed 5 genomes using the PacBio sequencing platform. Genomic data of eight human isolates were also downloaded from NCBI (National Center for Biotechnology Information) for comparative analysis. Fifteen Salmonella pathogenicity islands (SPIs) and a spv operon (spvRABCD), which encodes important virulence factors, were identified in all 69 (100%) isolates. The 15 SPIs were located on the chromosome of the 5 closed genomes, with each of these isolates also carrying 1 or 2 plasmids with sizes between 36 and 329?kb. Multiple antimicrobial resistance genes (ARGs), including blaCMY-2, blaTEM-1B, aadA12, aph(3′)-Ia, aph(3′)-Ic, strA, strB, floR, sul1, sul2, and tet(A), along with spv operons were identified on these plasmids. Comprehensive antimicrobial resistance genotypes were determined, including 17 genes encoding resistance to 5 different classes of antimicrobials, and mutations in the housekeeping gene (gyrA) associated with resistance or decreased susceptibility to fluoroquinolones. Together these data revealed that this panel of Salmonella Dublin commonly carried 15 SPIs, MDR/virulence plasmids, and ARGs against several classes of antimicrobials. Such genomic elements may make important contributions to the severity of disease and treatment failures in Salmonella Dublin infections in both humans and cattle.


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