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July 7, 2019

LRCstats, a tool for evaluating long reads correction methods.

Third-generation sequencing (TGS) platforms that generate long reads, such as PacBio and Oxford Nanopore technologies, have had a dramatic impact on genomics research. However, despite recent improvements, TGS reads suffer from high-error rates and the development of read correction methods is an active field of research. This motivates the need to develop tools that can evaluate the accuracy of noisy long reads correction tools.We introduce LRCstats, a tool that measures the accuracy of long reads correction tools. LRCstats takes advantage of long reads simulators that provide each simulated read with an alignment to the reference genome segment they originate from, and does not rely on a step of mapping corrected reads onto the reference genome. This allows for the measurement of the accuracy of the correction while being consistent with the actual errors introduced in the simulation process used to generate noisy reads. We illustrate the usefulness of LRCstats by analyzing the accuracy of four hybrid correction methods for PacBio long reads over three datasets.https://github.com/cchauve/lrcstats.laseanl@sfu.ca or cedric.chauve@sfu.ca.Supplementary data are available at Bioinformatics online.© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com


July 7, 2019

Centrochromatin of fungi.

The centromere is an essential chromosomal locus that dictates the nucleation point for assembly of the kinetochore and subsequent attachment of spindle microtubules during chromosome segregation. Research over the last decades demonstrated that centromeres are defined by a combination of genetic and epigenetic factors. Recent work showed that centromeres are quite diverse and flexible and that many types of centromere sequences and centromeric chromatin (“centrochromatin”) have evolved. The kingdom of the fungi serves as an outstanding example of centromere plasticity, including organisms with centromeres as diverse as 0.15-300 kb in length, and with different types of chromatin states for most species examined thus far. Some of the species in the less familiar taxa provide excellent opportunities to help us better understand centromere biology in all eukaryotes, which may improve treatment options against fungal infection, and biotechnologies based on fungi. This review summarizes the current knowledge of fungal centromeres and centrochromatin, including an outlook for future research.


July 7, 2019

Whole-genome de novo sequencing of the lignin-degrading wood rot fungus Phanerochaete chrysosporium (ATCC 20696).

Phanerochaete chrysosporium (ATCC 20696) has a catabolic ability to degrade lignin. Here, we report whole-genome sequencing used to identify genes related to lignin modification. We determined the 39-Mb draft genome sequence of this fungus, comprising 13,560 predicted gene models. Gene annotation provided crucial information about the location and function of protein-encoding genes. Copyright © 2017 Hong et al.


July 7, 2019

Taxonomic resolution of the nematophagous fungal isolate ARF18 via genome sequencing.

The taxonomically uncharacterized nematophagous fungus ARF18, which parasitizes cysts, juveniles, and adults of the soybean cyst nematode (Heterodera glycines), was proposed as a nematode biological control agent in 1991. A 46.3-Mb draft genome sequence of this fungus is presented, and a tentative taxonomic identification as a novel species of Brachyphoris is proposed. Copyright © 2017 Sharma et al.


July 7, 2019

Glycolytic functions are conserved in the genome of the wine yeast Hanseniaspora uvarum, and pyruvate kinase limits its capacity for alcoholic fermentation.

Hanseniaspora uvarum (anamorph Kloeckera apiculata) is a predominant yeast on wine grapes and other fruits and has a strong influence on wine quality, even when Saccharomyces cerevisiae starter cultures are employed. In this work, we sequenced and annotated approximately 93% of the H. uvarum genome. Southern and synteny analyses were employed to construct a map of the seven chromosomes present in a type strain. Comparative determinations of specific enzyme activities within the fermentative pathway in H. uvarum and S. cerevisiae indicated that the reduced capacity of the former yeast for ethanol production is caused primarily by an ~10-fold-lower activity of the key glycolytic enzyme pyruvate kinase. The heterologous expression of the encoding gene, H. uvarumPYK1 (HuPYK1), and two genes encoding the phosphofructokinase subunits, HuPFK1 and HuPFK2, in the respective deletion mutants of S. cerevisiae confirmed their functional homology.IMPORTANCEHanseniaspora uvarum is a predominant yeast species on grapes and other fruits. It contributes significantly to the production of desired as well as unfavorable aroma compounds and thus determines the quality of the final product, especially wine. Despite this obvious importance, knowledge on its genetics is scarce. As a basis for targeted metabolic modifications, here we provide the results of a genomic sequencing approach, including the annotation of 3,010 protein-encoding genes, e.g., those encoding the entire sugar fermentation pathway, key components of stress response signaling pathways, and enzymes catalyzing the production of aroma compounds. Comparative analyses suggest that the low fermentative capacity of H. uvarum compared to that of Saccharomyces cerevisiae can be attributed to low pyruvate kinase activity. The data reported here are expected to aid in establishing H. uvarum as a non-Saccharomyces yeast in starter cultures for wine and cider fermentations. Copyright © 2017 American Society for Microbiology.


July 7, 2019

Draft genome sequence of Aspergillus persii NIBRFGC000004109, which has antibacterial activity against plant-pathogenic bacteria.

The fungus Aspergillus persii strain NIBRFGC000004109 is capable of producing penicillic acid and showed antibacterial activity against various plant-pathogenic bacteria, including Xanthomonas arboricola pv. pruni. Here, we report the first draft whole-genome sequence of A. persii The assembly comprises 38,414,373 bp, with 12 scaffolds. Copyright © 2017 Kim et al.


July 7, 2019

Genome sequencing and comparative genomics reveal the potential pathogenic mechanism of Cercospora sojina Hara on soybean.

Frogeye leaf spot, caused by Cercospora sojina Hara, is a common disease of soybean in most soybean-growing countries of the world. In this study, we report a high-quality genome sequence of C. sojina by Single Molecule Real-Time sequencing method. The 40.8-Mb genome encodes 11,655 predicated genes, and 8,474 genes are revealed by RNA sequencing. Cercospora sojina genome contains large numbers of gene clusters that are involved in synthesis of secondary metabolites, including mycotoxins and pigments. However, much less carbohydrate-binding module protein encoding genes are identified in C. sojina genome, when compared with other phytopathogenic fungi. Bioinformatics analysis reveals that C. sojina harbours about 752 secreted proteins, and 233 of them are effectors. During early infection, the genes for metabolite biosynthesis and effectors are significantly enriched, suggesting that they may play essential roles in pathogenicity. We further identify 13 effectors that can inhibit BAX-induced cell death. Taken together, our results provide insights into the infection mechanisms of C. sojina on soybean.© The Author 2017. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.


July 7, 2019

Genome sequence of the white-rot fungus Irpex lacteus F17, a type strain of lignin degrader fungus.

Irpex lacteus, a cosmopolitan white-rot fungus, degrades lignin and lignin-derived aromatic compounds. In this study, we report the high-quality draft genome sequence of I. lacteus F17, isolated from a decaying hardwood tree in the vicinity of Hefei, China. The genome is 44,362,654 bp, with a GC content of 49.64% and a total of 10,391 predicted protein-coding genes. In addition, a total of 18 snRNA, 842 tRNA, 15 rRNA operons and 11,710 repetitive sequences were also identified. The genomic data provides insights into the mechanisms of the efficient lignin decomposition of this strain.


July 7, 2019

Root-associated fungal microbiota of nonmycorrhizal Arabis alpina and its contribution to plant phosphorus nutrition.

Most land plants live in association with arbuscular mycorrhizal (AM) fungi and rely on this symbiosis to scavenge phosphorus (P) from soil. The ability to establish this partnership has been lost in some plant lineages like the Brassicaceae, which raises the question of what alternative nutrition strategies such plants have to grow in P-impoverished soils. To understand the contribution of plant-microbiota interactions, we studied the root-associated fungal microbiome of Arabis alpina (Brassicaceae) with the hypothesis that some of its components can promote plant P acquisition. Using amplicon sequencing of the fungal internal transcribed spacer 2, we studied the root and rhizosphere fungal communities of A. alpina growing under natural and controlled conditions including low-P soils and identified a set of 15 fungal taxa consistently detected in its roots. This cohort included a Helotiales taxon exhibiting high abundance in roots of wild A. alpina growing in an extremely P-limited soil. Consequently, we isolated and subsequently reintroduced a specimen from this taxon into its native P-poor soil in which it improved plant growth and P uptake. The fungus exhibited mycorrhiza-like traits including colonization of the root endosphere and P transfer to the plant. Genome analysis revealed a link between its endophytic lifestyle and the expansion of its repertoire of carbohydrate-active enzymes. We report the discovery of a plant-fungus interaction facilitating the growth of a nonmycorrhizal plant under native P-limited conditions, thus uncovering a previously underestimated role of root fungal microbiota in P cycling.


July 7, 2019

Draft genome sequences of Trichophyton rubrum CMCC(F)T1i and Trichophyton violaceum CMCC(F)T3l by Illumina 2000 and Pacific Biosciences.

One strain of Trichophyton rubrum CMCC(F)T1i (=CBS 139224) isolated from onychomycosis and one strain of Trichophyton violaceum CMCC(F)T3l (=CBS 141829) isolated from tinea capitis in China were whole-genome sequenced by Illumina/Solexa, while the former was also sequenced by Pacific Biosciences sequencing in parallel. Copyright © 2017 Zhan et al.


July 7, 2019

Tryptorubin A: A polycyclic peptide from a fungus-derived Streptomycete.

Fungus-growing ants engage in complex symbiotic relationships with their fungal crop, specialized fungal pathogens, and bacteria that provide chemical defenses. In an effort to understand the evolutionary origins of this multilateral system, we investigated bacteria isolated from fungi. One bacterial strain (Streptomyces sp. CLI2509) from the bracket fungus Hymenochaete rubiginosa, produced an unusual peptide, tryptorubin A, which contains heteroaromatic links between side chains that give it a rigid polycyclic globular structure. The three-dimensional structure was determined by NMR and MS, including a (13)C-(13)C COSY of isotopically enriched material, degradation, derivatives, and computer modeling. Whole genome sequencing identified a likely pair of biosynthetic genes responsible for tryptorubin A’s linear hexapeptide backbone. The genome also revealed the close relationship between CLI2509 and Streptomyces sp. SPB78, which was previously implicated in an insect-bacterium symbiosis.


July 7, 2019

Complete mitochondrial genome sequence of Aspergillus oryzae RIB 127 and its comparative analysis with related species

Here, we determined the complete sequence and annotation of the mitochondrial genome of A. oryzae (strain RIB 127). The complete mitochondrial genome is 29,202 base pairs (bp), with low GC content of 26.2%. Conserved genes identified include 26 transfer RNAs, the small and large ribosomal RNA subunits, and 14 protein-coding genes. Phylogenetic analysis based on the complete mitochondrial genome revealed that RIB 127 formed a single clade with two other A. oryzae species.


July 7, 2019

Comparative genomics of maize ear rot pathogens reveals expansion of carbohydrate-active enzymes and secondary metabolism backbone genes in Stenocarpella maydis.

Stenocarpella maydis is a plant pathogenic fungus that causes Diplodia ear rot, one of the most destructive diseases of maize. To date, little information is available regarding the molecular basis of pathogenesis in this organism, in part due to limited genomic resources. In this study, a 54.8 Mb draft genome assembly of S. maydis was obtained with Illumina and PacBio sequencing technologies, and analyzed. Comparative genomic analyses with the predominant maize ear rot pathogens Aspergillus flavus, Fusarium verticillioides, and Fusarium graminearum revealed an expanded set of carbohydrate-active enzymes for cellulose and hemicellulose degradation in S. maydis. Analyses of predicted genes involved in starch degradation revealed six putative a-amylases, four extracellular and two intracellular, and two putative ?-amylases, one of which appears to have been acquired from bacteria via horizontal transfer. Additionally, 87 backbone genes involved in secondary metabolism were identified, which represents one of the largest known assemblages among Pezizomycotina species. Numerous secondary metabolite gene clusters were identified, including two clusters likely involved in the biosynthesis of diplodiatoxin and chaetoglobosins. The draft genome of S. maydis presented here will serve as a useful resource for molecular genetics, functional genomics, and analyses of population diversity in this organism. Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.


July 7, 2019

Harnessing whole genome sequencing in medical mycology.

Comparative genome sequencing studies of human fungal pathogens enable identification of genes and variants associated with virulence and drug resistance. This review describes current approaches, resources, and advances in applying whole genome sequencing to study clinically important fungal pathogens.Genomes for some important fungal pathogens were only recently assembled, revealing gene family expansions in many species and extreme gene loss in one obligate species. The scale and scope of species sequenced is rapidly expanding, leveraging technological advances to assemble and annotate genomes with higher precision. By using iteratively improved reference assemblies or those generated de novo for new species, recent studies have compared the sequence of isolates representing populations or clinical cohorts. Whole genome approaches provide the resolution necessary for comparison of closely related isolates, for example, in the analysis of outbreaks or sampled across time within a single host.Genomic analysis of fungal pathogens has enabled both basic research and diagnostic studies. The increased scale of sequencing can be applied across populations, and new metagenomic methods allow direct analysis of complex samples.


July 7, 2019

Genome sequence of the lager-brewing yeast Saccharomyces sp. strain M14, used in the high-gravity brewing industry in China.

Lager-brewing yeasts are mainly used for the production of lager beers. Illumina and PacBio-based sequence analyses revealed an approximate genome size of 22.8 Mb, with a GC content of 38.98%, for the Chinese lager-brewing yeast Saccharomyces sp. strain M14. Based on ab initio prediction, 9,970 coding genes were annotated. Copyright © 2017 Liu et al.


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