A high-quality Actinidia chinensis (kiwifruit) genome

Abstract Actinidia chinensis (kiwifruit) is a perennial horticultural crop species of the Actinidiaceae family with high nutritional and economic value. Two versions of the A. chinensis genomes have been previously assembled, based mainly on relatively short reads. Here, we report an improved chromosome-level reference genome of A. chinensis (v3.0), based mainly on PacBio long reads and Hi-C data. The high-quality assembled genome is 653 Mb long, with 0.76% heterozygosity. At least 43% of the genome consists of repetitive sequences, and the most abundant long terminal repeats were further identified and account for 23.38% of our novel genome. It has clear improvements in contiguity, accuracy, and gene annotation over the two previous versions and contains 40,464 annotated protein-coding genes, of which 94.41% are functionally annotated. Moreover, further analyses of genetic collinearity revealed that the kiwifruit genome has undergone two whole-genome duplications: one affecting all Ericales families near the K-T extinction event and a recent genus-specific duplication. The reference genome presented here will be highly useful for further molecular elucidation of diverse traits and for the breeding of this horticultural crop, as well as evolutionary studies with related taxa.

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A high-quality chromosome-level genome assembly reveals genetics for important traits in eggplant

Horticulture Research ◽

10.1038/s41438-020-00391-0 ◽

2020 ◽

Vol 7 (1) ◽

Author(s):

Qingzhen Wei ◽

Jinglei Wang ◽

Wuhong Wang ◽

Tianhua Hu ◽

Haijiao Hu ◽

...

Keyword(s):

Genome Assembly ◽

Reference Genome ◽

Repetitive Sequences ◽

Gene Families ◽

Specific Gene ◽

High Quality ◽

Total Size ◽

Protein Coding ◽

Fruit Length ◽

Protein Coding Genes

Abstract Eggplant (Solanum melongena L.) is an economically important vegetable crop in the Solanaceae family, with extensive diversity among landraces and close relatives. Here, we report a high-quality reference genome for the eggplant inbred line HQ-1315 (S. melongena-HQ) using a combination of Illumina, Nanopore and 10X genomics sequencing technologies and Hi-C technology for genome assembly. The assembled genome has a total size of ~1.17 Gb and 12 chromosomes, with a contig N50 of 5.26 Mb, consisting of 36,582 protein-coding genes. Repetitive sequences comprise 70.09% (811.14 Mb) of the eggplant genome, most of which are long terminal repeat (LTR) retrotransposons (65.80%), followed by long interspersed nuclear elements (LINEs, 1.54%) and DNA transposons (0.85%). The S. melongena-HQ eggplant genome carries a total of 563 accession-specific gene families containing 1009 genes. In total, 73 expanded gene families (892 genes) and 34 contraction gene families (114 genes) were functionally annotated. Comparative analysis of different eggplant genomes identified three types of variations, including single-nucleotide polymorphisms (SNPs), insertions/deletions (indels) and structural variants (SVs). Asymmetric SV accumulation was found in potential regulatory regions of protein-coding genes among the different eggplant genomes. Furthermore, we performed QTL-seq for eggplant fruit length using the S. melongena-HQ reference genome and detected a QTL interval of 71.29–78.26 Mb on chromosome E03. The gene Smechr0301963, which belongs to the SUN gene family, is predicted to be a key candidate gene for eggplant fruit length regulation. Moreover, we anchored a total of 210 linkage markers associated with 71 traits to the eggplant chromosomes and finally obtained 26 QTL hotspots. The eggplant HQ-1315 genome assembly can be accessed at http://eggplant-hq.cn. In conclusion, the eggplant genome presented herein provides a global view of genomic divergence at the whole-genome level and powerful tools for the identification of candidate genes for important traits in eggplant.

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A High-continuity and Annotated Tomato Reference Genome

10.21203/rs.3.rs-579393/v1 ◽

2021 ◽

Author(s):

Xiao Su ◽

Baoan Wang ◽

Xiaolin Geng ◽

Yuefan Du ◽

Qinqin Yang ◽

...

Keyword(s):

Reference Genome ◽

Agronomic Traits ◽

Repetitive Sequences ◽

Tomato Genome ◽

Ideal Model ◽

Model Species ◽

Horticultural Crop ◽

Protein Coding ◽

Genetic Mechanisms ◽

High Quality Genome

Abstract Background: Genetic and functional genomics studies require a high-quality genome assembly. Tomato (Solanum lycopersicum), an important horticultural crop, is an ideal model species for the study of fruit development. Results: Here, we assembled an updated reference genome of S. lycopersicum cv. Heinz 1706 that was 799.09 Mb in length, containing 34,384 predicted protein-coding genes and 65.66% repetitive sequences. By comparing the genomes of S. lycopersicum and S. pimpinellifolium LA2093, we found a large number of genomic fragments probably associated with human selection, which may have had crucial roles in the domestication of tomato. We also used a recombinant inbred line (RIL) population to generate a high-density genetic map with high resolution and accuracy. Using these resources, we identified a number of candidate genes that were likely to be related to important agronomic traits in tomato. Conclusion:Our results offer opportunities for understanding the evolution of the tomato genome and will facilitate the study of genetic mechanisms in tomato biology.

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A high-continuity and annotated tomato reference genome

BMC Genomics ◽

10.1186/s12864-021-08212-x ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Xiao Su ◽

Baoan Wang ◽

Xiaolin Geng ◽

Yuefan Du ◽

Qinqin Yang ◽

...

Keyword(s):

Reference Genome ◽

Agronomic Traits ◽

Repetitive Sequences ◽

Tomato Genome ◽

Ideal Model ◽

Model Species ◽

Horticultural Crop ◽

Protein Coding ◽

Genetic Mechanisms ◽

High Quality Genome

Abstract Background Genetic and functional genomics studies require a high-quality genome assembly. Tomato (Solanum lycopersicum), an important horticultural crop, is an ideal model species for the study of fruit development. Results Here, we assembled an updated reference genome of S. lycopersicum cv. Heinz 1706 that was 799.09 Mb in length, containing 34,384 predicted protein-coding genes and 65.66% repetitive sequences. By comparing the genomes of S. lycopersicum and S. pimpinellifolium LA2093, we found a large number of genomic fragments probably associated with human selection, which may have had crucial roles in the domestication of tomato. We also used a recombinant inbred line (RIL) population to generate a high-density genetic map with high resolution and accuracy. Using these resources, we identified a number of candidate genes that were likely to be related to important agronomic traits in tomato. Conclusion Our results offer opportunities for understanding the evolution of the tomato genome and will facilitate the study of genetic mechanisms in tomato biology.

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A Chromosome-Scale Genome Assembly Resource for Myriosclerotinia sulcatula Infecting Sedge Grass (Carex sp.)

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-03-20-0060-a ◽

2020 ◽

Vol 33 (7) ◽

pp. 880-883

Author(s):

Stefan Kusch ◽

Heba M. M. Ibrahim ◽

Catherine Zanchetta ◽

Celine Lopez-Roques ◽

Cecile Donnadieu ◽

...

Keyword(s):

Host Range ◽

Sclerotinia Sclerotiorum ◽

Genome Assembly ◽

Plant Pathogens ◽

Reference Genome ◽

Close Relative ◽

High Quality ◽

Protein Coding ◽

Protein Coding Genes ◽

Reference Genome Assembly

The fungus Myriosclerotinia sulcatula is a close relative of the notorious polyphagous plant pathogens Botrytis cinerea and Sclerotinia sclerotiorum but exhibits a host range restricted to plants from the Carex genus (Cyperaceae family). To date, there are no genomic resources available for fungi in the Myriosclerotinia genus. Here, we present a chromosome-scale reference genome assembly for M. sulcatula. The assembly contains 24 contigs with a total length of 43.53 Mbp, with scaffold N50 of 2,649.7 kbp and N90 of 1,133.1 kbp. BRAKER-predicted gene models were manually curated using WebApollo, resulting in 11,275 protein-coding genes that we functionally annotated. We provide a high-quality reference genome assembly and annotation for M. sulcatula as a resource for studying evolution and pathogenicity in fungi from the Sclerotiniaceae family.

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De Novo Sequencing, Assembly, and Annotation of Four Threespine Stickleback Genomes Based on Microfluidic Partitioned DNA Libraries

Genes ◽

10.3390/genes10060426 ◽

2019 ◽

Vol 10 (6) ◽

pp. 426 ◽

Cited By ~ 3

Author(s):

Daniel Berner ◽

Marius Roesti ◽

Steven Bilobram ◽

Simon K. Chan ◽

Heather Kirk ◽

...

Keyword(s):

Reference Genome ◽

De Novo ◽

Gene Annotation ◽

Model System ◽

Threespine Stickleback ◽

Evolutionary Genomics ◽

Digital Repository ◽

High Quality ◽

De Novo Gene ◽

Dna Libraries

The threespine stickleback is a geographically widespread and ecologically highly diverse fish that has emerged as a powerful model system for evolutionary genomics and developmental biology. Investigations in this species currently rely on a single high-quality reference genome, but would benefit from the availability of additional, independently sequenced and assembled genomes. We present here the assembly of four new stickleback genomes, based on the sequencing of microfluidic partitioned DNA libraries. The base pair lengths of the four genomes reach 92–101% of the standard reference genome length. Together with their de novo gene annotation, these assemblies offer a resource enhancing genomic investigations in stickleback. The genomes and their annotations are available from the Dryad Digital Repository (https://doi.org/10.5061/dryad.113j3h7).

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Draft genome of the Reindeer (Rangifer tarandus)

10.1101/154724 ◽

2017 ◽

Author(s):

Zhipeng Li ◽

Zeshan Lin ◽

Lei Chen ◽

Hengxing Ba ◽

Yongzhi Yang ◽

...

Keyword(s):

Rangifer Tarandus ◽

Reference Genome ◽

De Novo ◽

Bos Taurus ◽

Repetitive Sequences ◽

Draft Genome ◽

Divergence Time ◽

Capra Hircus ◽

High Quality ◽

Illumina Hiseq

AbstractBackgroundReindeer (Rangifer tarandus) is the only fully domesticated species in the Cervidae family, and is the only cervid with a circumpolar distribution. Unlike all other cervids, female reindeer regularly grow cranial appendages (antlers, the defining characteristics of cervids), as well as males. Moreover, reindeer milk contains more protein and less lactose than bovids’ milk. A high quality reference genome of this specie will assist efforts to elucidate these and other important features in the reindeer.FindingsWe obtained 723.2 Gb (Gigabase) of raw reads by an Illumina Hiseq 4000 platform, and a 2.64 Gb final assembly, representing 95.7% of the estimated genome (2.76 Gb according to k-mer analysis), including 92.6% of expected genes according to BUSCO analysis. The contig N50 and scaffold N50 sizes were 89.7 kilo base (kb) and 0.94 mega base (Mb), respectively. We annotated 21,555 protein-coding genes and 1.07 Gb of repetitive sequences by de novo and homology-based prediction. Homology-based searches detected 159 rRNA, 547 miRNA, 1,339 snRNA and 863 tRNA sequences in the genome of R. tarandus. The divergence time between R. tarandus, and ancestors of Bos taurus and Capra hircus, is estimated to be 29.55 million years ago (Mya).ConclusionsOur results provide the first high-quality reference genome for the reindeer, and a valuable resource for studying evolution, domestication and other unusual characteristics of the reindeer.

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Assembly of chromosome-scale contigs by efficiently resolving repetitive sequences with long reads

10.1101/345983 ◽

2018 ◽

Cited By ~ 2

Author(s):

Huilong Du ◽

Chengzhi Liang

Keyword(s):

Single Molecule ◽

High Efficiency ◽

Reference Genome ◽

Repetitive Sequences ◽

Sequencing Data ◽

High Quality ◽

Single Molecule Sequencing ◽

Genome Maps ◽

Long Reads ◽

Novel Method

AbstractDue to the large number of repetitive sequences in complex eukaryotic genomes, fragmented and incompletely assembled genomes lose value as reference sequences, often due to short contigs that cannot be anchored or mispositioned onto chromosomes. Here we report a novel method Highly Efficient Repeat Assembly (HERA), which includes a new concept called a connection graph as well as algorithms for constructing the graph. HERA resolves repeats at high efficiency with single-molecule sequencing data, and enables the assembly of chromosome-scale contigs by further integrating genome maps and Hi-C data. We tested HERA with the genomes of rice R498, maize B73, human HX1 and Tartary buckwheat Pinku1. HERA can correctly assemble most of the tandemly repetitive sequences in rice using single-molecule sequencing data only. Using the same maize and human sequencing data published by Jiao et al. (2017) and Shi et al. (2016), respectively, we dramatically improved on the sequence contiguity compared with the published assemblies, increasing the contig N50 from 1.3 Mb to 61.2 Mb in maize B73 assembly and from 8.3 Mb to 54.4 Mb in human HX1 assembly with HERA. We provided a high-quality maize reference genome with 96.9% of the gaps filled (only 76 gaps left) and several incorrectly positioned sequences fixed compared with the B73 RefGen_v4 assembly. Comparisons between the HERA assembly of HX1 and the human GRCh38 reference genome showed that many gaps in GRCh38 could be filled, and that GRCh38 contained some potential errors that could be fixed. We assembled the Pinku1 genome into 12 scaffolds with a contig N50 size of 27.85 Mb. HERA serves as a new genome assembly/phasing method to generate high quality sequences for complex genomes and as a curation tool to improve the contiguity and completeness of existing reference genomes, including the correction of assembly errors in repetitive regions.

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Analyzing and characterization of the chloroplast genome of Salix suchowensis

10.7287/peerj.preprints.2388 ◽

2016 ◽

Author(s):

Congrui Sun ◽

Jie Li ◽

Xiaogang Dai ◽

Yingnan Chen

Keyword(s):

Tandem Repeats ◽

Gene Annotation ◽

Repetitive Sequences ◽

Single Copy ◽

Phylogenetic Position ◽

Shrub Willow ◽

Protein Coding ◽

Protein Coding Genes ◽

Cp Genome ◽

Rna Genes

By screening sequence reads from the chloroplast (cp) genome of S. suchowensis that generated by the next generation sequencing platforms, we built the complete circular pseudomolecule for its cp genome. This pseudomolecule is 155,508 bp in length, which has a typical quadripartite structure containing two single copy regions, a large single copy region (LSC 84,385 bp), and a small single copy region (SSC 16,209 bp) separated by inverted repeat regions (IRs 27,457 bp). Gene annotation revealed that the cp genome of S. suchowensis encoded 119 unique genes, including 4 ribosome RNA genes, 30 transfer RNA genes, 82 protein-coding genes and 3 pseudogenes. Analyzing the repetitive sequences detected 15 tandem repeats, 16 forward repeats and 5 palindromic repeats. In addition, a total of 188 perfect microsatellites were detected, which were characterized as A/T predominance in nucleotide compositions. Significant shifting of the IR/SSC boundaries was revealed by comparing this cp genome with that of other rosids plants. We also built phylogenetic trees to demonstrate the phylogenetic position of S. suchowensis in Rosidae, with 66 orthologous protein-coding genes presented in the cp genomes of 32 species. By sequencing 30 amplicons based on the pseudomolecule, experimental verification achieved accuracy up to 99.84% for the cp genome assembly of S. suchowensis. In conclusion, this study built a high quality pseudomolecule for the cp genome of S. suchowensis, which is a useful resource for facilitating the development of this shrub willow into a more productive bioenergy crop.

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The first high-quality chromosomal genome assembly of a medicinal and edible plant Arctium lappa

10.22541/au.162012034.41527060/v1 ◽

2021 ◽

Author(s):

Liang Xu ◽

Shengnan Li ◽

Yanyun Yang ◽

Yanping Xing ◽

Zhongren Zhang ◽

...

Keyword(s):

Candidate Genes ◽

Developmental Stages ◽

Repetitive Sequences ◽

Draft Genome ◽

Edible Plant ◽

High Quality ◽

Protein Coding ◽

Arctium Lappa ◽

Coa Ligase ◽

Highly Correlated

Arctium lappa has a long medicinal and edible history with great economic importance. We combined Illumina and PacBio sequences to generate the first high-quality chromosome-level draft genome of A. lappa. The assembled genome is approximately 1.79 Gb with a N50 contig size of 6.88 Mb. Approximately 1.70 Gb (95.4%) of the contig sequences were anchored onto 18 chromosomes using Hi-C data; the scaffold N50 was improved to be 91.64 Mb. Furthermore, we obtained 1.12 Gb (68.46%) of repetitive sequences and 32,771 protein-coding genes; 616 positively selected candidate genes were identified. Additionally, we compared the transcriptomes of A. lappa roots at three different developmental stages and identified 8,943 differentially expressed genes (DEGs) in these tissues. Among candidate genes related to lignan biosynthesis, the following were found to be highly correlated with the accumulation of arctiin: 4-coumarate-CoA ligase (4CL), dirigent protein (DIR), and hydroxycinnamoyl transferase (HCT). These data can be utilized to identify genes related to A. lappa quality or provide a basis for molecular identification and comparative genomics among related species.

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Chromosome-Level Genome Assembly Reveals Significant Gene Expansion in the Toll and IMD Signaling Pathways of Dendrolimus kikuchii

Frontiers in Genetics ◽

10.3389/fgene.2021.728418 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jielong Zhou ◽

Peifu Wu ◽

Zhongping Xiong ◽

Naiyong Liu ◽

Ning Zhao ◽

...

Keyword(s):

Genome Assembly ◽

Phylogenetic Analyses ◽

Repetitive Sequences ◽

Gene Families ◽

Thaumetopoea Pityocampa ◽

High Quality ◽

Protein Coding ◽

Peptidoglycan Recognition Protein ◽

Recognition Protein ◽

Chromosome Level

A high-quality genome is of significant value when seeking to control forest pests such as Dendrolimus kikuchii, a destructive member of the order Lepidoptera that is widespread in China. Herein, a high quality, chromosome-level reference genome for D. kikuchii based on Nanopore, Pacbio HiFi sequencing and the Hi-C capture system is presented. Overall, a final genome assembly of 705.51 Mb with contig and scaffold N50 values of 20.89 and 24.73 Mb, respectively, was obtained. Of these contigs, 95.89% had unique locations on 29 chromosomes. In silico analysis revealed that the genome contained 15,323 protein-coding genes and 63.44% repetitive sequences. Phylogenetic analyses indicated that D. kikuchii may diverged from the common ancestor of Thaumetopoea. Pityocampa, Thaumetopoea ni, Heliothis virescens, Hyphantria armigera, Spodoptera frugiperda, and Spodoptera litura approximately 122.05 million years ago. Many gene families were expanded in the D. kikuchii genome, particularly those of the Toll and IMD signaling pathway, which included 10 genes in peptidoglycan recognition protein, 19 genes in MODSP, and 11 genes in Toll. The findings from this study will help to elucidate the mechanisms involved in protection of D. kikuchii against foreign substances and pathogens, and may highlight a potential channel to control this pest.

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