High-quality genome assembly of Pseudocercospora ulei the main threat to natural rubber trees.
Ontology highlight
ABSTRACT:
SUBMITTER: Gonzalez-Sayer S
PROVIDER: S-EPMC8762716 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:We report the acquisition of a high-quality haploid chromosome-scale genome assembly for the first time in a tree species, Eucommia ulmoides, which is known for its rubber biosynthesis and medicinal applications. The assembly was obtained by applying PacBio and Hi-C technologies to a haploid that we specifically generated. Compared to the initial genome release, this one has significantly improved assembly quality. The scaffold N50 (53.15 MB) increased 28-fold, and the repetitive sequence content (520 Mb) increased by 158.24 Mb, whereas the number of gaps decreased from 104,772 to 128. A total of 92.87% of the 26,001 predicted protein-coding genes identified with multiple strategies were anchored to the 17 chromosomes. A new whole-genome duplication event was superimposed on the earlier γ paleohexaploidization event, and the expansion of long terminal repeats contributed greatly to the evolution of the genome. The more primitive rubber biosynthesis of this species, as opposed to that in Hevea brasiliensis, relies on the methylerythritol-phosphate pathway rather than the mevalonate pathway to synthesize isoprenyl diphosphate, as the MEP pathway operates predominantly in trans-polyisoprene-containing leaves and central peels. Chlorogenic acid biosynthesis pathway enzymes were preferentially expressed in leaves rather than in bark. This assembly with higher sequence contiguity can foster not only studies on genome structure and evolution, gene mapping, epigenetic analysis and functional genomics but also efforts to improve E. ulmoides for industrial and medical uses through genetic engineering.
| S-EPMC7603500 | biostudies-literature
Project description:Closing gaps in draft genome assemblies can be costly and time-consuming, and published genomes are therefore often left 'unfinished.' Here we show that genome-wide chromosome conformation capture (3C) data can be used to overcome these limitations, and present a computational approach rooted in polymer physics that determines the most likely genome structure using chromosomal contact data. This algorithm--named GRAAL--generates high-quality assemblies of genomes in which repeated and duplicated regions are accurately represented and offers a direct probabilistic interpretation of the computed structures. We first validated GRAAL on the reference genome of Saccharomyces cerevisiae, as well as other yeast isolates, where GRAAL recovered both known and unknown complex chromosomal structural variations. We then applied GRAAL to the finishing of the assembly of Trichoderma reesei and obtained a number of contigs congruent with the know karyotype of this species. Finally, we showed that GRAAL can accurately reconstruct human chromosomes from either fragments generated in silico or contigs obtained from de novo assembly. In all these applications, GRAAL compared favourably to recently published programmes implementing related approaches.
| S-EPMC4284522 | biostudies-literature
Project description:Earthworms enrich the soil and protect the health of their ecological environment. Previous studies on these invertebrates determined their protein content, hormone secretions, medicinal value, and ecological habits, but their whole genomic sequence remains incomplete. We performed whole genome sequencing of Metaphire vulgaris (Chen, 1930), which belongs to the genus Metaphire of the family Megascolecidae. The genome assembly was 729 Mb, with a N50 contig size of 4.2 Mb. In total, 559 contigs were anchored to 41 chromosomes according to the results of Hi-C (High-throughput Chromosome Conformation Capture) technology, which was confirmed by karyological analysis. A comparison of the genomic sequences and genes indicated that there was a whole-genome duplication in M. vulgaris followed by several chromosome fusion events. Hox genes and lumbrokinase genes were identified as partial clusters surrounding the genome. Our high-quality genome assembly of M. vulgaris will provide valuable information for gene function and evolutionary studies in earthworms.
| S-EPMC7666815 | biostudies-literature
Project description:Diospyros oleifera Cheng, of the family Ebenaceae, is an economically important tree. Phylogenetic analyses indicate that D. oleifera is closely related to Diospyros kaki Thunb. and could be used as a model plant for studies of D. kaki. Therefore, development of genomic resources of D. oleifera will facilitate auxiliary assembly of the hexaploid persimmon genome and elucidate the molecular mechanisms of important traits. The D. oleifera genome was assembled with 443.6 Gb of raw reads using the Pacific Bioscience Sequel and Illumina HiSeq X Ten platforms. The final draft genome was ∼812.3 Mb and had a high level of continuity with N50 of 3.36 Mb. Fifteen scaffolds corresponding to the 15 chromosomes were assembled to a final size of 721.5 Mb using 332 scaffolds, accounting for 88.81% of the genome. Repeat sequences accounted for 54.8% of the genome. By de novo sequencing and analysis of homology with other plant species, 30,530 protein-coding genes with an average transcript size of 7,105.40 bp were annotated; of these, 28,580 protein-coding genes (93.61%) had conserved functional motifs or terms. In addition, 171 candidate genes involved in tannin synthesis and deastringency in persimmon were identified; of these chalcone synthase (CHS) genes were expanded in the D. oleifera genome compared with Diospyros lotus, Camellia sinensis, and Vitis vinifera. Moreover, 186 positively selected genes were identified, including chalcone isomerase (CHI) gene, a key enzyme in the flavonoid-anthocyanin pathway. Phylogenetic tree analysis indicated that the split of D. oleifera and D. lotus likely occurred 9.0 million years ago. In addition to the ancient γ event, a second whole-genome duplication event occurred in D. oleifera and D. lotus. We generated a high-quality chromosome-level draft genome for D. oleifera, which will facilitate assembly of the hexaploid persimmon genome and further studies of major economic traits in the genus Diospyros.
| S-EPMC6964648 | biostudies-literature
Project description:BackgroundThe channel catfish (Ictalurus punctatus), a species native to North America, is one of the most important commercial freshwater fish in the world, especially in the United States' aquaculture industry. Since its introduction into China in 1984, both cultivation area and yield of this species have been dramatically increased such that China is now the leading producer of channel catfish. To aid genomic research in this species, data sets such as genetic linkage groups, long-insert libraries, physical maps, bacterial artificial clones (BAC) end sequences (BES), transcriptome assemblies, and reference genome sequences have been generated. Here, using diverse assembly methods, we provide a comparable high-quality genome assembly for a channel catfish from a breeding stock inbred in China for more than three generations, which was originally imported to China from North America.FindingsApproximately 201.6 gigabases (Gb) of genome reads were sequenced by the Illumina HiSeq 2000 platform. Subsequently, we generated high quality, cost-effective and easily assembled sequences of the channel catfish genome with a scaffold N50 of 7.2 Mb and 95.6 % completeness. We also predicted that the channel catfish genome contains 21,556 protein-coding genes and 275.3 Mb (megabase pairs) of repetitive sequences.ConclusionsWe report a high-quality genome assembly of the channel catfish, which is comparable to a recent report of the "Coco" channel catfish. These generated genome data could be used as an initial platform for molecular breeding to obtain novel catfish varieties using genomic approaches.
| S-EPMC4994213 | biostudies-literature
Project description:ObjectivesLasiodiplodia pseudotheobromae is an important fungal pathogen associated with die-back, canker and shoot blight in many plant hosts with a wide geographic distribution. The aim of our study was to provide high-quality genome assemblies and sequence annotation resources of L. pseudotheobromae, to facilitate future studies on the systematics, population genetics and genomics of the fungal pathogen L. pseudotheobromae.Data descriptionHigh-quality genomes of five L. pseudotheobromae isolates were sequenced based on Oxford Nanopore technology (ONT) and Illumina HiSeq sequencing platform. The total size of each assembly ranged from 43 Mb to 43.86 Mb and over 11,000 protein-coding genes were predicted from each genome. The proteins of predicted genes were annotated using multiple public databases, among the annotated protein-coding genes, more than 4,300 genes were predicted as potential virulence genes by the Pathogen Host Interactions (PHI) database. Moreover, the genome comparative analysis among L. pseudotheobromae and other closely related species revealed that 7,408 gene clusters were shared among them and 152 gene clusters unique to L. pseudotheobromae. This genome and associated datasets provided here will serve as a useful resource for further analyses of this fungal pathogen species.
| S-EPMC10759541 | biostudies-literature
Project description:In the present work, a highly pathogenic isolate of Fusarium oxysporum f. sp. lini, which is the most harmful pathogen affecting flax (Linum usitatissimum L.), was sequenced for the first time. To achieve a high-quality genome assembly, we used the combination of two sequencing platforms - Oxford Nanopore Technologies (MinION system) with long noisy reads and Illumina (HiSeq 2500 instrument) with short accurate reads. Given the quality of DNA is crucial for Nanopore sequencing, we developed the protocol for extraction of pure high-molecular-weight DNA from fungi. Sequencing of DNA extracted using this protocol allowed us to obtain about 85x genome coverage with long (N50 = 29 kb) MinION reads and 30x coverage with 2 × 250 bp HiSeq reads. Several tools were developed for genome assembly; however, they provide different results depending on genome complexity, sequencing data volume, read length and quality. We benchmarked the most requested assemblers (Canu, Flye, Shasta, wtdbg2, and MaSuRCA), Nanopore polishers (Medaka and Racon), and Illumina polishers (Pilon and POLCA) on our sequencing data. The assembly performed with Canu and polished with Medaka and POLCA was considered the most full and accurate. After further elimination of redundant contigs using Purge Haplotigs, we achieved a high-quality genome of F. oxysporum f. sp. lini with a total length of 59 Mb, N50 of 3.3 Mb, and 99.5% completeness according to BUSCO. We also obtained a complete circular mitochondrial genome with a length of 38.7 kb. The achieved assembly expands studies on F. oxysporum and plant-pathogen interaction in flax.
| S-EPMC7481384 | biostudies-literature
Project description:The decreasing costs of next-generation sequencing and the improvements in de novo sequence assemblers have made it possible to obtain reference genomes for most eukaryotes, including minor crops such as the blueberry (Vaccinium corymbosum). Nevertheless, these genomes are at various levels of completeness and few have been anchored to chromosome scale and/or are haplotype-phased. We highlight the impact of a high-quality genome assembly for plant breeding and genetic research by showing how it affects our understanding of the genetic architecture of important traits and aids marker selection and candidate gene detection. We compared the results of genome-wide association studies and genomic selection that were already published using a blueberry draft genome as reference with the results using the recent released chromosome-scale and haplotype-phased blueberry genome. We believe that the benefits shown herein reinforce the importance of genome assembly projects for other non-model species.
| S-EPMC6558523 | biostudies-literature
Project description:As an important freshwater aquaculture species in China, the Chinese mitten crab (Eriocheir japonica sinensis) has high economic and nutritional value. However, limited genomic information is currently available for studying its basic development and genetic diversity. Here, we performed whole-genome sequencing on Oxford Nanopore Technologies Limited's platform using promethION. The assembled size of E. j.sinensis genome was approximately 1.27 Gb, which is close to the estimated size (1.19 Gb). Furthermore, based on assessment using Benchmarking Universal Single-Copy Orthologs (BUSCO) (Simao et al., 2015), 94.00% of the expected eukaryotic genes were completely present in the genome assembly. In addition, repetitive sequences accounted for ~61.42% of the assembled genome, and 22,619 protein-coding genes were annotated. Comparative genomics analysis demonstrated that the Chinese mitten crab diverged from Penaeus vannamei ~373.6 million years ago, with a faster evolution rate than shrimp. We anticipate that the annotated high-quality genome of E. j. sinensis will promote research on its basic development and evolution and make substantial contributions to comparative genomic analyses of crustaceans.
| S-EPMC6979310 | biostudies-literature
Project description:BackgroundGenerating high-quality de novo genome assemblies is foundational to the genomics study of model and non-model organisms. In recent years, long-read sequencing has greatly benefited genome assembly and scaffolding, a process by which assembled sequences are ordered and oriented through the use of long-range information. Long reads are better able to span repetitive genomic regions compared to short reads, and thus have tremendous utility for resolving problematic regions and helping generate more complete draft assemblies. Here, we present LongStitch, a scalable pipeline that corrects and scaffolds draft genome assemblies exclusively using long reads.ResultsLongStitch incorporates multiple tools developed by our group and runs in up to three stages, which includes initial assembly correction (Tigmint-long), followed by two incremental scaffolding stages (ntLink and ARKS-long). Tigmint-long and ARKS-long are misassembly correction and scaffolding utilities, respectively, previously developed for linked reads, that we adapted for long reads. Here, we describe the LongStitch pipeline and introduce our new long-read scaffolder, ntLink, which utilizes lightweight minimizer mappings to join contigs. LongStitch was tested on short and long-read assemblies of Caenorhabditis elegans, Oryza sativa, and three different human individuals using corresponding nanopore long-read data, and improves the contiguity of each assembly from 1.2-fold up to 304.6-fold (as measured by NGA50 length). Furthermore, LongStitch generates more contiguous and correct assemblies compared to state-of-the-art long-read scaffolder LRScaf in most tests, and consistently improves upon human assemblies in under five hours using less than 23 GB of RAM.ConclusionsDue to its effectiveness and efficiency in improving draft assemblies using long reads, we expect LongStitch to benefit a wide variety of de novo genome assembly projects. The LongStitch pipeline is freely available at https://github.com/bcgsc/longstitch .
| S-EPMC8557608 | biostudies-literature