Universal Single-Copy Orthologs Research Articles

Nematode genome announcement: The draft genome sequence of entomopathogenic nematode Heterorhabditis indica.

Heterorhabditis indica is one of the most widely used entomopathogenic nematodes for the biological control of agricultural insect pests worldwide. The draft genome of H. indica was sequenced using three genomic libraries of 300 bp, 600 bp and 5 kb sizes by Illumina HiSeq platform. The size of the draft genome assembly was 91.26 Mb, comprising 3,538 scaffolds. Genome completeness analysis by BUSCO (Benchmarking Universal Single-Copy Orthologs) showed 84% complete, and 6.5% fragmented BUSCOs. Further, 10,494 protein-coding genes were predicted. The H. indica draft genome will enable comparative and functional genomic studies in Heterorhabditis nematodes.

The First Draft Genome of a Cold-Water Coral Trachythela sp. (Alcyonacea: Stolonifera: Clavulariidae).

Cold-water corals (CWCs) are important habitats for creatures in the deep-sea environment, but they have been degraded by anthropogenic activity. So far, no genome for any CWC has been reported. Here, we report a draft genome of Trachythela sp., which represents the first genome of CWCs to date. In total, 56 and 65 Gb of raw reads were generated from Illumina and Nanopore sequencing platforms, respectively. The final assembled genome was 578.26 Mb, which consisted of 396 contigs with a contig N50 of 3.56 Mb, and the genome captured 90.1% of the metazoan Benchmarking Universal Single-Copy Orthologs. We identified 335 Mb (57.88% of the genome) of repetitive elements, which is a higher proportion compared with others in the Cnidarians, along with 35,305 protein-coding genes. We also detected 483 expanded and 51 contracted gene families, and many of them were associated with longevity, ion transposase, heme-binding nicotinamide adenine dinucleotide, and metabolic regulators of transcription. Overall, we believe this genome will serve as an important resource for studies on community protection for CWCs.

De novo assembly of a chromosome-scale reference genome for the northern flicker Colaptes auratus.

The northern flicker, Colaptes auratus, is a widely distributed North American woodpecker and a long-standing focal species for the study of ecology, behavior, phenotypic differentiation, and hybridization. We present here a highly contiguous de novo genome assembly of C. auratus, the first such assembly for the species and the first published chromosome-level assembly for woodpeckers (Picidae). The assembly was generated using a combination of short-read Chromium 10× and long-read PacBio sequencing, and further scaffolded with chromatin conformation capture (Hi-C) reads. The resulting genome assembly is 1.378 Gb in size, with a scaffold N50 of 11 and a scaffold L50 of 43.948 Mb. This assembly contains 87.4–91.7% of genes present across four sets of universal single-copy orthologs found in tetrapods and birds. We annotated the assembly both for genes and repetitive content, identifying 18,745 genes and a prevalence of ∼28.0% repetitive elements. Lastly, we used fourfold degenerate sites from neutrally evolving genes to estimate a mutation rate for C. auratus, which we estimated to be 4.007 × 10−9 substitutions/site/year, about 1.5× times faster than an earlier mutation rate estimate of the family. The highly contiguous assembly and annotations we report will serve as a resource for future studies on the genomics of C. auratus and comparative evolution of woodpeckers.

Genome assembly and annotation of the California harvester ant Pogonomyrmex californicus.

The harvester ant genus Pogonomyrmex is endemic to arid and semiarid habitats and deserts of North and South America. The California harvester ant Pogonomyrmex californicus is the most widely distributed Pogonomyrmex species in North America. Pogonomyrmex californicus colonies are usually monogynous, i.e. a colony has one queen. However, in a few populations in California, primary polygyny evolved, i.e. several queens cooperate in colony founding after their mating flights and continue to coexist in mature colonies. Here, we present a genome assembly and annotation of P. californicus. The size of the assembly is 241 Mb, which is in agreement with the previously estimated genome size. We were able to annotate 17,889 genes in total, including 15,688 protein-coding ones with BUSCO (Benchmarking Universal Single-Copy Orthologs) completeness at a 95% level. The presented P. californicus genome assembly will pave the way for investigations of the genomic underpinnings of social polymorphism in the number of queens, regulation of aggression, and the evolution of adaptations to dry habitats.

A chromosome-level genome assembly of rice leaffolder, Cnaphalocrocis medinalis.

The rice leaffolder, Cnaphalocrocis medinalis Guenée (Crambidae, Lepidoptera), is an important agricultural pest that causes serious losses to rice production in rice-growing regions with high humidity and temperature. However, a lack of genomic resources limits in-depth understanding of its biological characteristics and ecological adaptation. Here, we sequenced the genome of rice leaffolder using the Illumina and PacBio platforms, yielding a genome assembly of 528.3Mb with a contig N50 of 524.6kb. A high percentage (96.4%) of Benchmarking Universal Single-Copy Orthologs (BUSCOs) were successfully detected, suggesting high-level completeness of the genome assembly. In total, 39.5% of the genome consists of repeat sequences and 15,045 protein-coding genes were annotated. Comparative phylogenomic analysis showed that some gene families associated with hormone biosynthesis expanded in rice leaffolder. Next, we used the Hi-C technique to produce a chromosome-level genome assembly with a scaffold N50 of 16.1Mb by anchoring 3,248 scaffolds to 31 chromosomes. The rice leaffolder genome showed high chromosomal synteny with the genome of four other lepidopteran insects. By comparing coverage ratios from the genome resequencing of male and female pupae, we identified near intact Z and W chromosomes. The W chromosome is estimated as 20.75Mb, which is the most complete known W chromosome in Lepidoptera. The protein-coding genes on the W chromosome were significantly enriched in metabolic pathways. In all, the high-quality genome assembly and the near-intact W chromosome of rice leaffolder should be a useful resource for the fields of insect migration, chromosome evolution and pest control.

Pacific Biosciences assembly with Hi-C mapping generates an improved, chromosome-level goose genome.

ABSTRACTBackgroundThe domestic goose is an economically important and scientifically valuable waterfowl; however, a lack of high-quality genomic data has hindered research concerning its genome, genetics, and breeding. As domestic geese breeds derive from both the swan goose (Anser cygnoides) and the graylag goose (Anser anser), we selected a female Tianfu goose for genome sequencing. We generated a chromosome-level goose genome assembly by adopting a hybrid de novo assembly approach that combined Pacific Biosciences single-molecule real-time sequencing, high-throughput chromatin conformation capture mapping, and Illumina short-read sequencing.FindingsWe generated a 1.11-Gb goose genome with contig and scaffold N50 values of 1.85 and 33.12 Mb, respectively. The assembly contains 39 pseudo-chromosomes (2n = 78) accounting for ∼88.36% of the goose genome. Compared with previous goose assemblies, our assembly has more continuity, completeness, and accuracy; the annotation of core eukaryotic genes and universal single-copy orthologs has also been improved. We have identified 17,568 protein-coding genes and a repeat content of 8.67% (96.57 Mb) in this genome assembly. We also explored the spatial organization of chromatin and gene expression in the goose liver tissues, in terms of inter-pseudo-chromosomal interaction patterns, compartments, topologically associating domains, and promoter-enhancer interactions.ConclusionsWe present the first chromosome-level assembly of the goose genome. This will be a valuable resource for future genetic and genomic studies on geese.

A chromosome-level genome assembly of the woolly apple aphid, Eriosoma lanigerum Hausmann (Hemiptera: Aphididae).

Woolly apple aphid (WAA, Eriosoma lanigerum Hausmann) (Hemiptera: Aphididae) is a major pest of apple trees (Malus domestica, order Rosales) and is critical to the economics of the apple industry in most parts of the world. Here, we generated a chromosome-level genome assembly of WAA-representing the first genome sequence from the aphid subfamily Eriosomatinae-using a combination of 10X Genomics linked-reads and in vivo Hi-C data. The final genome assembly is 327Mb, with 91% of the assembled sequences anchored into six chromosomes. The contig and scaffold N50 values are 158kb and 71Mb, respectively, and we predicted a total of 28,186 protein-coding genes. The assembly is highly complete, including 97% of conserved arthropod single-copy orthologues based on Benchmarking Universal Single-Copy Orthologs (busco) analysis. Phylogenomic analysis of WAA and nine previously published aphid genomes, spanning four aphid tribes and three subfamilies, reveals that the tribe Eriosomatini (represented by WAA) is recovered as a sister group to Aphidini+Macrosiphini (subfamily Aphidinae). We identified syntenic blocks of genes between our WAA assembly and the genomes of other aphid species and find that two WAA chromosomes (El5 and El6) map to the conserved Macrosiphini and Aphidini X chromosome. Our high-quality WAA genome assembly and annotation provides a valuable resource for research in a broad range of areas such as comparative and population genomics, insect-plant interactions and pest resistance management.

A Genome Resource for the Apple Powdery Mildew Pathogen Podosphaera leucotricha.

Powdery mildew, caused by Podosphaera leucotricha, is an economically important disease of apple and pear trees. A single monoconidial strain (PuE-3) of this biotrophic fungus was used to extract DNA for Illumina sequencing. Data were assembled to form a draft genome of 43.8 Mb consisting of 8,921 contigs, 9,372 predicted genes, and 96.1% of complete benchmarking universal single copy orthologs (BUSCOs). This is the first reported genome sequence of P. leucotricha that will enable studies of the population biology, epidemiology, and fungicide resistance of this pathogen. Furthermore, this resource will be fundamental to uncover the genetic and molecular mechanisms of the apple-powdery mildew interaction, and support future pome fruit breeding efforts.

An evaluation of methodology to determine algal genome completeness

The advancement of sequencing technologies has resulted in a rapid expansion of genome sequencing. One challenge in processing and analyzing this abundance of genomics data is development and application of tools to accurately assess the quality of novel genomes. The quality of a given genome assembly is commonly assessed using the presence of conserved orthologs. However, the applicability and accuracy of identifying conserved orthologs applied to algal genome assemblies, which are uniquely diverse, is unclear. Here, we analyze the utility of a genome content assessment tool, Benchmarking Universal Single-Copy Orthologs (BUSCO), to evaluate algal genome assembly completeness. We find that Chlorophyta and Stramenopile BUSCO databases are effective tools to analyze genome completeness of these lineages. For other lineages, the Eukaryota database should be utilized until additional lineage-specific databases are developed. Based on these results, suggested best practices for current usage and necessary future improvements are provided.

Taro Genome Assembly and Linkage Map Reveal QTLs for Resistance to Taro Leaf Blight.

Taro (Colocasia esculenta) is a food staple widely cultivated in the humid tropics of Asia, Africa, Pacific and the Caribbean. One of the greatest threats to taro production is Taro Leaf Blight caused by the oomycete pathogen Phytophthora colocasiae. Here we describe a de novo taro genome assembly and use it to analyze sequence data from a Taro Leaf Blight resistant mapping population. The genome was assembled from linked-read sequences (10x Genomics; ∼60x coverage) and gap-filled and scaffolded with contigs assembled from Oxford Nanopore Technology long-reads and linkage map results. The haploid assembly was 2.45 Gb total, with a maximum contig length of 38 Mb and scaffold N50 of 317,420 bp. A comparison of family-level (Araceae) genome features reveals the repeat content of taro to be 82%, >3.5x greater than in great duckweed (Spirodela polyrhiza), 23%. Both genomes recovered a similar percent of Benchmarking Universal Single-copy Orthologs, 80% and 84%, based on a 3,236 gene database for monocot plants. A greater number of nucleotide-binding leucine-rich repeat disease resistance genes were present in genomes of taro than the duckweed, ∼391 vs. ∼70 (∼182 and ∼46 complete). The mapping population data revealed 16 major linkage groups with 520 markers, and 10 quantitative trait loci (QTL) significantly associated with Taro Leaf Blight disease resistance. The genome sequence of taro enhances our understanding of resistance to TLB, and provides markers that may accelerate breeding programs. This genome project may provide a template for developing genomic resources in other understudied plant species.

RNA-seq: The early response of the snail Physella acuta to the digenetic trematode Echinostoma paraensei.

To analyze the response of the snail Physella acuta to Echinostoma paraensei, a compatible digenetic trematode, Illumina RNA-seq data were collected from snails with early infection (5 snails at 2 days post-exposure [DPE]) and established infection (4 snails, 8 DPE), and 7 control (unexposed) snails. A reference transcriptome (325,563 transcripts, including 98% of eukaryotic universal single-copy orthologs; BUSCO) and a draft P. acuta genome (employing available genomic Illumina reads; 799,945 scaffolds, includes 88% BUSCO genes) were assembled to guide RNA-seq analyses. Parasite exposure of P. acuta led to 10,195 differentially expressed (DE) genes at 2 DPE and 8,876 DE genes at 8 DPE with only 18% of up-regulated and 22% of down-regulated sequences shared between these time points. Gene ontology (GO) analysis yielded functional annotation of only 1.2% of DE genes but did not indicate major changes in biological activities of P. acuta between 2 and 8 DPE. Increased insights were achieved by analysis of expression profiles of 460 immune-relevant DE transcripts, identified by BLAST and InterProScan. Physella acuta has expanded gene families that encode immune-relevant domains, including CD109/TEP, GTPase IMAP, Limulus agglutination factor (dermatopontin), FReD (≥82 sequences with fibrinogen-related domains), and transcripts that combine C-type lectin (C-LECT) and C1q domains, novel among metazoa. Notably, P. acuta expressed sequences from these immune gene families at all time points, but the assemblages of unique transcripts from particular immune gene families differed between 2 and 8 DPE. The shift in profiles of DE immune genes, from early exposure to parasite establishment, suggests that compatible P. acuta initially respond to infection but switch to express immune genes that likely are less effective against E. paraensei but counter other types of (opportunistic) pathogens and parasites. We propose that the latter expression profile is part of an extended phenotype of E. paraensei, imposed upon P. acuta through parasite manipulation of the host, following successful parasite establishment in the snail after 2 DPE.

RNA-sequencing based gene expression landscape of guava cv. Allahabad Safeda and comparative analysis to colored cultivars

BackgroundGuava (Psidium guajava L.) is an important fruit crop of tropical and subtropical areas of the world. Genomics resources in guava are scanty. RNA-Seq based tissue specific expressed genomic information, de novo transcriptome assembly, functional annotation and differential expression among contrasting genotypes has a potential to set the stage for the functional genomics for traits of commerce like colored flesh and apple color peel.ResultsDevelopment of fruit from flower involves orchestration of myriad molecular switches. We did comparative transcriptome sequencing on leaf, flower and fruit tissues of cv. Allahabad Safeda to understand important genes and pathways controlling fruit development. Tissue specific RNA sequencing and de novo transcriptome assembly using Trinity pipeline provided us the first reference transcriptome for guava consisting of 84,206 genes comprising 279,792 total transcripts with a N50 of 3603 bp. Blast2GO assigned annotation to 116,629 transcripts and PFam based HMM profile annotated 140,061 transcripts with protein domains. Differential expression with EdgeR identified 3033 genes in Allahabad Safeda tissues. Mapping the differentially expressed transcripts over molecular pathways indicate significant Ethylene and Abscisic acid hormonal changes and secondary metabolites, carbohydrate metabolism and fruit softening related gene transcripts during fruit development, maturation and ripening. Differential expression analysis among colored tissue comparisons in 3 cultivars Allahabad Safeda, Punjab Pink and Apple Color identified 68 candidate genes that might be controlling color development in guava fruit. Comparisons of red vs green peel in Apple Color, white pulp vs red pulp in Punjab Pink and fruit maturation vs ripening in non-colored Allahabad Safeda indicates up-regulation of ethylene biosynthesis accompanied to secondary metabolism like phenylpropanoid and monolignol pathways.ConclusionsBenchmarking Universal Single-Copy Orthologs analysis of de novo transcriptome of guava with eudicots identified 93.7% complete BUSCO genes. In silico differential gene expression among tissue types of Allahabad Safeda and validation of candidate genes with qRT-PCR in contrasting color genotypes promises the utility of this first guava transcriptome for its potential of tapping the genetic elements from germplasm collections for enhancing fruit traits.

A chromosome-level genome assembly of the parasitoid wasp Pteromalus puparum.

Parasitoid wasps represent a large proportion of hymenopteran species. They have complex evolutionary histories and are important biocontrol agents. To advance parasitoid research, a combination of Illumina short-read, PacBio long-read and Hi-C scaffolding technologies was used to develop a high-quality chromosome-level genome assembly for Pteromalus puparum, which is an important pupal endoparasitoid of caterpillar pests. The chromosome-level assembly has aided in studies of venom and detoxification genes. The assembled genome size is 338Mb with a contig N50 of 38.7kb and a scaffold N50 of 1.16Mb. Hi-C analysis assembled scaffolds onto five chromosomes and raised the scaffold N50 to 65.8Mb, with more than 96% of assembled bases located on chromosomes. Gene annotation was assisted by RNA sequencing for the two sexes and four different life stages. Analysis detected 98% of the BUSCO (Benchmarking Universal Single-Copy Orthologs) gene set, supporting a high-quality assembly and annotation. In total, 40.1% (135.6Mb) of the assembly is composed of repetitive sequences, and 14,946 protein-coding genes were identified. Although venom genes play important roles in parasitoid biology, their spatial distribution on chromosomes was poorly understood. Mapping has revealed venom gene tandem arrays for serine proteases, pancreatic lipase-related proteins and kynurenine-oxoglutarate transaminases, which have amplified in the P.puparum lineage after divergence from its common ancestor with Nasonia vitripennis. In addition, there is a large expansion of P450 genes in P.puparum. These examples illustrate how chromosome-level genome assembly can provide a valuable resource for molecular, evolutionary and biocontrol studies of parasitoid wasps.

Liver transcriptome resources of four commercially exploited teleost species

The generation of omic resources is central to develop adequate management strategies for species with economic value. Here, we provide high-coverage RNA-seq datasets of liver tissue (containing between 80,2 and 88,4 million of paired-end reads) from four wildtype teleost species with high commercial value: Trachurus trachurus (TTR; Atlantic horse mackerel), Scomber scombrus (SSC; Atlantic mackerel), Trisopterus luscus (TLU; pout), and Micromesistius poutassou (MPO; blue whiting). A comprehensive assembly pipeline, using de novo single and multi-kmer assembly approaches, produced 64 single high-quality liver transcriptomes – 16 per species. The final assemblies, with N50 values ranging from 2,543–3,700 bp and BUSCO (Benchmarking Universal Single-Copy Orthologs) completeness values between 81.8–86.5% of the Actinopterygii gene set, were subjected to open reading frame (ORF) prediction and functional annotation. Our study provides the first transcriptomic resources for these species and offers valuable tools to evaluate both neutral and selected genetic variation among populations, and to identify candidate genes for environmental adaptation assisting in the investigation of the effects of global changes in fisheries.

The First Draft Genome Assembly of Snow Sheep (Ovis nivicola).

The snow sheep, Ovis nivicola, which is endemic to the mountain ranges of northeastern Siberia, are well adapted to the harsh cold climatic conditions of their habitat. In this study, using long reads of Nanopore sequencing technology, whole-genome sequencing, assembly, and gene annotation of a snow sheep were carried out. Additionally, RNA-seq reads from several tissues were also generated to supplement the gene prediction in snow sheep genome. The assembled genome was ∼2.62 Gb in length and was represented by 7,157 scaffolds with N50 of about 2 Mb. The repetitive sequences comprised of 41% of the total genome. BUSCO analysis revealed that the snow sheep assembly contained full-length or partial fragments of 97% of mammalian universal single-copy orthologs (n = 4,104), illustrating the completeness of the assembly. In addition, a total of 20,045 protein-coding sequences were identified using comprehensive gene prediction pipeline. Of which 19,240 (∼96%) sequences were annotated using protein databases. Moreover, homology-based searches and de novo identification detected 1,484 tRNAs; 243 rRNAs; 1,931 snRNAs; and 782 miRNAs in the snow sheep genome. To conclude, we generated the first de novo genome of the snow sheep using long reads; these data are expected to contribute significantly to our understanding related to evolution and adaptation within the Ovis genus.

Dataset of de novo assembly and functional annotation of the transcriptomes of three native oleaginous microalgae from the Peruvian Amazon.

Microalgae are photosynthetic organisms with cosmopolitan distribution (i.e., marine, freshwater and terrestrial habitats) and possess a great diversity of species [1] and consequently an immense variation in biochemical compositions [2]. To date genomic information is available mainly from the model green microalga Chlamydomonas reinhardtii[3]. Here we provide the dataset of a de novo assembly and functional annotation of the transcriptomes of three native oleaginous microalgae from the Peruvian Amazon. Native oleaginous microalgae species Ankistrodesmus sp., Chlorella sp., and Scenedesmus sp. were cultured in triplicate using Chu-10 medium with or without a source of nitrate (NaNO3). Total RNA was purified, the cDNA libraries were constructed and sequenced as paired-end reads on an Illumina HiSeq™2500 platform. Transcriptomes were de novo assembled using Trinity v2.9.1. A total of 48,554 transcripts (range from 250 to 7966 bp; N50 = 1047) for Ankistrodesmus sp., 108,126 transcripts (range from 250 to 8160 bp; N50 = 1090) for Chlorella sp., and 77,689 transcripts (range from 250 to 8481 bp; N50 = 1281) for Scenedesmus sp. were de novo assembled. Completeness of the assembled transcriptomes were evaluated with the Benchmarking Universal Single-Copy Orthologs (BUSCO) software v2/v3. Functional annotation of the assembled transcriptomes was conducted with TransDecoder v3.0.1 and the web-based platforms Kyoto Encyclopedia of Genes and Genomes (KEGG) Automatic Annotation Server (KAAS) and FunctionAnnotator. The raw reads were deposited into NCBI and are accessible via BioProject accession number PRJNA628966 (https://www.ncbi.nlm.nih.gov/bioproject/PRJNA628966) and Sequence Read Archive (SRA) with accession numbers: SRX8295665 (https://www.ncbi.nlm.nih.gov/sra/SRX8295665), SRX8295666 (https://www.ncbi.nlm.nih.gov/sra/SRX8295666), SRX8295667 (https://www.ncbi.nlm.nih.gov/sra/SRX8295667), SRX8295668 (https://www.ncbi.nlm.nih.gov/sra/SRX8295668), SRX8295669 (https://www.ncbi.nlm.nih.gov/sra/SRX8295669), and SRX8295670 (https://www.ncbi.nlm.nih.gov/sra/SRX8295670). Additionally, transcriptome shotgun assembly sequences and functional annotations are available via Discover Mendeley Data (https://data.mendeley.com/datasets/47wdjmw9xr/1).

An improved genome assembly and annotation of the Antarctic copepod Tigriopus kingsejongensis and comparison of fatty acid metabolism between T. kingsejongensis and the temperate copepod T. japonicus

Copepods in the genus Tigriopus are widely distributed in the intertidal zone worldwide. To assess differences in fatty acid (FA) metabolism among congeneric species in this genus inhabiting polar and temperate environments, we analyzed and compared FA profiles of the Antarctic copepod Tigriopus kingsejongensis and the temperate copepod T. japonicus. Higher amounts of total FAs were found in the Antarctic copepod T. kingsejongensis than the temperate copepod T. japonicus under administration of the identical amount of Tetraselmis suecica. To determine the genomic basis for this, we identified fatty acid metabolism-related genes in an improved genome of T. kingsejongensis. The total length of the assembled genome was approximately 338 Mb with N50 = 1.473 Mb, 938 scaffolds, and a complete Benchmarking Universal Single-Copy Orthologs value of 95.8%. A total of 25,470 genes were annotated using newly established pipeline. We identified eight elongation of very long-chain fatty acid protein (Elovl) genes and nine fatty acid desaturase (Fad) genes in the genome of T. kingsejongensis. In addition, fatty acid profiling suggested that the duplicated Δ5/6 desaturase gene in T. kingsejongensis is likely to play an essential role in synthesis of different FAs in T. kingsejongensis to those in T. japonicus. However, further experimental research is required to validate our in silico findings. This study provides a better understanding of fatty acid metabolism in the Antarctic copepod T. kingsejongensis.

Dataset of de novo assembly and functional annotation of the transcriptome during germination and initial growth of seedlings of Myrciaria Dubia "camu-camu".

Myrciaria dubia “camu-camu” is a native shrub of the Amazon that is commonly found in areas that are flooded for three to four months during the annual hydrological cycle. This plant species is exceptional for its capacity to biosynthesize and accumulate important quantities of a variety of health-promoting phytochemicals, especially vitamin C [1], yet few genomic resources are available [2]. Here we provide the dataset of a de novo assembly and functional annotation of the transcriptome from a pool of samples obtained from seeds during the germination process and seedlings during the initial growth (until one month after germination). Total RNA/mRNA was purified from different types of plant materials (i.e., imbibited seeds, germinated seeds, and seedlings of one, two, three, and four weeks old), pooled in equimolar ratio to generate the cDNA library and RNA paired-end sequencing was conducted on an Illumina HiSeq™2500 platform. The transcriptome was de novo assembled using Trinity v2.9.1 and SuperTranscripts v2.9.1. A total of 21,161 transcripts were assembled ranging in size from 500 to 10,001 bp with a N50 value of 1,485 bp. Completeness of the assembly dataset was assessed using the Benchmarking Universal Single-Copy Orthologs (BUSCO) software v2/v3. Finally, the assembled transcripts were functionally annotated using TransDecoder v3.0.1 and the web-based platforms Kyoto Encyclopedia of Genes and Genomes (KEGG) Automatic Annotation Server (KAAS), and FunctionAnnotator. The raw reads were deposited into NCBI and are accessible via BioProject accession number PRJNA615000 (https://www.ncbi.nlm.nih.gov/bioproject/PRJNA615000) and Sequence Read Archive (SRA) with accession number SRX7990430 (https://www.ncbi.nlm.nih.gov/sra/SRX7990430). Additionally, transcriptome shotgun assembly sequences and functional annotations are available via Discover Mendeley Data (https://data.mendeley.com/datasets/2csj3h29fr/1).

Draft genome of the Native American cold hardy grapevine Vitis riparia Michx. \u2018Manitoba 37\u2019

Vitis riparia, a critically important Native American grapevine species, is used globally in rootstock and scion breeding and contributed to the recovery of the French wine industry during the mid-19th century phylloxera epidemic. This species has abiotic and biotic stress tolerance and the largest natural geographic distribution of the North American grapevine species. Here we report an Illumina short-read 369X coverage, draft de novo heterozygous genome sequence of V. riparia Michx. ‘Manitoba 37’ with the size of ~495 Mb for 69,616 scaffolds and a N50 length of 518,740 bp. Using RNAseq data, 40,019 coding sequences were predicted and annotated. Benchmarking with Universal Single-Copy Orthologs (BUSCO) analysis of predicted gene models found 96% of the complete BUSCOs in this assembly. The assembly continuity and completeness were further validated using V. riparia ESTs, BACs, and three de novo transcriptome assemblies of three different V. riparia genotypes resulting in >98% of respective sequences/transcripts mapping with this assembly. Alignment of the V. riparia assembly and predicted CDS with the latest V. vinifera ‘PN40024’ CDS and genome assembly showed 99% CDS alignment and a high degree of synteny. An analysis of plant transcription factors indicates a high degree of homology with the V. vinifera transcription factors. QTL mapping to V. riparia ‘Manitoba 37’ and V. vinifera PN40024 has identified genetic relationships to phenotypic variation between species. This assembly provides reference sequences, gene models for marker development and understanding V. riparia’s genetic contributions in grape breeding and research.

De Novo Genome Assembly of Limpet Bathyacmaea lactea (Gastropoda: Pectinodontidae): The First Reference Genome of a Deep-Sea Gastropod Endemic to Cold Seeps.

Cold seeps, characterized by the methane, hydrogen sulfide, and other hydrocarbon chemicals, foster one of the most widespread chemosynthetic ecosystems in deep sea that are densely populated by specialized benthos. However, scarce genomic resources severely limit our knowledge about the origin and adaptation of life in this unique ecosystem. Here, we present a genome of a deep-sea limpet Bathyacmaea lactea, a common species associated with the dominant mussel beds in cold seeps. We yielded 54.6 gigabases (Gb) of Nanopore reads and 77.9-Gb BGI-seq raw reads, respectively. Assembly harvested a 754.3-Mb genome for B. lactea, with 3,720 contigs and a contig N50 of 1.57 Mb, covering 94.3% of metazoan Benchmarking Universal Single-Copy Orthologs. In total, 23,574 protein-coding genes and 463.4 Mb of repetitive elements were identified. We analyzed the phylogenetic position, substitution rate, demographic history, and TE activity of B. lactea. We also identified 80 expanded gene families and 87 rapidly evolving Gene Ontology categories in the B. lactea genome. Many of these genes were associated with heterocyclic compound metabolism, membrane-bounded organelle, metal ion binding, and nitrogen and phosphorus metabolism. The high-quality assembly and in-depth characterization suggest the B. lactea genome will serve as an essential resource for understanding the origin and adaptation of life in the cold seeps.