scholarly journals Genome Sequence Resource of Phytophthora colocasiae from China Using Nanopore Sequencing Technology

Plant Disease ◽  
2021 ◽  
Author(s):  
Zhixin Wang ◽  
Jiandong Bao ◽  
Lin Lv ◽  
Lianyu Lin ◽  
Zhiting Li ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Protein Coding ◽  
Short Read ◽  
Rxlr Effectors ◽  
Phytophthora Colocasiae ◽  
Oxford Nanopore ◽  
Long Read ◽  
Infection Mechanisms ◽  
Oomycete Pathogen ◽  
Taro Leaf Blight

Phytophthora colocasiae is a destructive oomycete pathogen of taro (Colocasia esculenta), which causes taro leaf blight. To date, only one highly fragmented Illumina short-read-based genome assembly is available for this species. To address this problem, we sequenced strain Lyd2019 from China using Oxford Nanopore Technologies (ONT) long-read sequencing and Illumina short-read sequencing. We generated a 92.51-Mb genome assembly consisting of 105 contigs with an N50 of 1.70 Mb and a maximum length of 4.17 Mb. In the genome assembly, we identified 52.78% repeats and 18,322 protein-coding genes, of which 12,782 genes were annotated. We also identified 191 candidate RXLR effectors and 1 candidate CRN effectors. The updated near-chromosome genome assembly and annotation resources will provide a better understanding of the infection mechanisms of P. colocasiae.

scholarly journals Genome Sequence Data of Peronophythora litchii, an Oomycete Pathogen Causing Litchi Downy Blight

2021 ◽  
Author(s):  
Hengyuan Guo ◽  
Jiandong Bao ◽  
Lianyu Lin ◽  
Zhixin Wang ◽  
Mingyue Shi ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Sequence Data ◽  
Protein Coding ◽  
Rxlr Effectors ◽  
Oxford Nanopore ◽  
Long Read ◽  
Infection Mechanisms ◽  
Oomycete Pathogen ◽  
High Quality Genome ◽  
Oxford Nanopore Technologies

Peronophythora litchii is an oomycete pathogen that exclusively infects litchi, with infection stages affecting a broad range of tissues. In this study, we obtained a near chromosome-level genome assembly of P. litchii strain ZL2018 from China using Oxford Nanopore Technologies (ONT) long-read sequencing and Illumina short-read sequencing. The genome assembly was 64.15 Mb in size and consisted of 81 contigs with an N50 of 1.43 Mb and a maximum length of 4.74 Mb. Excluding 34.67% of repeat sequences, a total of 14,857 protein-coding genes were identified, among which 14,447 genes were annotated. We also predicted 306 candidate RXLR effectors in the assembly. The high-quality genome assembly and annotation resources reported in this study will provide new insight into the infection mechanisms of P. litchii.

scholarly journals The first genome assembly of fungal pathogen Pyrenophora tritici-repentis race 1 isolate using Oxford Nanopore MinION sequencing

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Paula Moolhuijzen ◽  
Pao Theen See ◽  
Caroline S. Moffat
Keyword(s):  
Genome Assembly ◽  
Fungal Pathogen ◽  
Large Scale ◽  
Gc Content ◽  
Tan Spot ◽  
Short Read ◽  
Short Reads ◽  
Pyrenophora Tritici Repentis ◽  
Oxford Nanopore ◽  
Long Read

Abstract Objectives The assembly of fungal genomes using short-reads is challenged by long repetitive and low GC regions. However, long-read sequencing technologies, such as PacBio and Oxford Nanopore, are able to overcome many problematic regions, thereby providing an opportunity to improve fragmented genome assemblies derived from short reads only. Here, a necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr) isolate 134 (Ptr134), which causes tan spot disease on wheat, was sequenced on a MinION using Oxford Nanopore Technologies (ONT), to improve on a previous Illumina short-read genome assembly and provide a more complete genome resource for pan-genomic analyses of Ptr. Results The genome of Ptr134 sequenced on a MinION using ONT was assembled into 28 contiguous sequences with a total length of 40.79 Mb and GC content of 50.81%. The long-read assembly provided 6.79 Mb of new sequence and 2846 extra annotated protein coding genes as compared to the previous short-read assembly. This improved genome sequence represents near complete chromosomes, an important resource for large scale and pan genomic comparative analyses.

scholarly journals A highly contiguous genome assembly of Brassica nigra (BB) and revised nomenclature for the pseudochromosomes

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Kumar Paritosh ◽  
Akshay Kumar Pradhan ◽  
Deepak Pental
Keyword(s):  
Genome Assembly ◽  
Indian Subcontinent ◽  
Brassica Nigra ◽  
Oilseed Crop ◽  
Protein Coding ◽  
Repeat Elements ◽  
Gene Block ◽  
B Genome ◽  
Oxford Nanopore ◽  
Long Read

Abstract Background Brassica nigra (BB), also called black mustard, is grown as a condiment crop in India. B. nigra represents the B genome of U’s triangle and is one of the progenitor species of B. juncea (AABB), an important oilseed crop of the Indian subcontinent. We report the genome assembly of B. nigra variety Sangam. Results The genome assembly was carried out using Oxford Nanopore long-read sequencing and optical mapping. A total of 1549 contigs were assembled, which covered ~ 515.4 Mb of the estimated ~ 522 Mb of the genome. The final assembly consisted of 15 scaffolds that were assigned to eight pseudochromosomes using a high-density genetic map of B. nigra. Around 246 Mb of the genome consisted of the repeat elements; LTR/Gypsy types of retrotransposons being the most predominant. The B genome-specific repeats were identified in the centromeric regions of the B. nigra pseudochromosomes. A total of 57,249 protein-coding genes were identified of which 42,444 genes were found to be expressed in the transcriptome analysis. A comparison of the B genomes of B. nigra and B. juncea revealed high gene colinearity and similar gene block arrangements. A comparison of the structure of the A, B, and C genomes of U’s triangle showed the B genome to be divergent from the A and C genomes for gene block arrangements and centromeric regions. Conclusions A highly contiguous genome assembly of the B. nigra genome reported here is an improvement over the previous short-read assemblies and has allowed a comparative structural analysis of the A, B, and C genomes of the species belonging to the U’s triangle. Based on the comparison, we propose a new nomenclature for B. nigra pseudochromosomes, taking the B. rapa pseudochromosome nomenclature as the reference.

scholarly journals High-quality genome assembly and annotation resource of Botryosphaeria dothidea strain BDLA16-7, causing trunk canker disease on Chinese hickory

Plant Disease ◽  
2021 ◽  
Author(s):  
Jiandong Bao ◽  
Q. Q. Wu ◽  
Jianqin Huang ◽  
Chuan-Qing Zhang
Keyword(s):  
Genome Assembly ◽  
Gene Clusters ◽  
Botryosphaeria Dothidea ◽  
Cytochrome P450 Enzymes ◽  
Protein Coding ◽  
Canker Disease ◽  
Host Interaction ◽  
Oxford Nanopore ◽  
Infection Mechanisms ◽  
High Quality Genome

Botryosphaeria dothidea is a latent pathogen with global importance to woody plant health, which causes serious tree trunk cankers on Chinese hickory. To date, only one Illumina short-read-based genome assembly of strain CK16 is available for host Chinese hickory. To address this problem, we reported a near telomere-to-telomere genome assembly of strain BDLA16-7 (46.05 Mb, N50 3.87 Mb) using Oxford Nanopore Sequencing Technology. Our genome assembly was consisted of 15 contigs, of which, 3 were assembled into chromosomal level and the maximum contig length was 6.19 Mb. The assembly contained 7.96% repeats and 12,815 protein-coding genes (10,274 genes were functional annotated). We also identified 3,642 pathogen-host interaction (PHI) genes, 250 carbohydrateactive enzymes (CAZymes), 252 cytochrome P450 enzymes (CYPs), 752 putative secreted proteins and 63 secondary metabolite biosynthesis gene clusters (SMBGCs). The BUSCO completeness of genome assembly and predicted genes was 99.34% and 97.50%, respectively, at fungal level (n=758). The almost chromosomal-level and well-annotated genome assembly will provide a valuable genetic resource for understanding of the infection mechanisms of B. dothidea in future.

scholarly journals Amynthas corticis genome reveals molecular mechanisms behind global distribution

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xing Wang ◽  
Yi Zhang ◽  
Yufeng Zhang ◽  
Mingming Kang ◽  
Yuanbo Li ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Molecular Mechanisms ◽  
Gene Families ◽  
The Body ◽  
Gene Family Evolution ◽  
Complex Environments ◽  
Protein Coding ◽  
Itraq Analysis ◽  
Rdna Sequencing ◽  
Long Read

AbstractEarthworms (Annelida: Crassiclitellata) are widely distributed around the world due to their ancient origination as well as adaptation and invasion after introduction into new habitats over the past few centuries. Herein, we report a 1.2 Gb complete genome assembly of the earthworm Amynthas corticis based on a strategy combining third-generation long-read sequencing and Hi-C mapping. A total of 29,256 protein-coding genes are annotated in this genome. Analysis of resequencing data indicates that this earthworm is a triploid species. Furthermore, gene family evolution analysis shows that comprehensive expansion of gene families in the Amynthas corticis genome has produced more defensive functions compared with other species in Annelida. Quantitative proteomic iTRAQ analysis shows that expression of 147 proteins changed in the body of Amynthas corticis and 16 S rDNA sequencing shows that abundance of 28 microorganisms changed in the gut of Amynthas corticis when the earthworm was incubated with pathogenic Escherichia coli O157:H7. Our genome assembly provides abundant and valuable resources for the earthworm research community, serving as a first step toward uncovering the mysteries of this species, and may provide molecular level indicators of its powerful defensive functions, adaptation to complex environments and invasion ability.

Dual Isoform Sequencing Reveals a Multifaceted Transcriptional Architecture of a Prototype Baculovirus

2021 ◽  
Author(s):  
Gábor Torma ◽  
Dóra Tombácz ◽  
Norbert Moldován ◽  
Ádám Fülöp ◽  
István Prazsák ◽  
...  
Keyword(s):  
Protein Coding ◽  
Rna Molecules ◽  
Non Coding Rna ◽  
Oxford Nanopore ◽  
The Pacific ◽  
Viral Genes ◽  
Long Read ◽  
Oxford Nanopore Technologies ◽  
Overlapping Transcripts

Abstract In this study, we used two long-read sequencing (LRS) techniques, Sequel from the Pacific Biosciences and MinION from Oxford Nanopore Technologies, for the transcriptional characterization of a prototype baculovirus, Autographacalifornica multiple nucleopolyhedrovirus. LRS is able to read full-length RNA molecules, and thereby to distinguish between transcript isoforms, mono- and polycistronic RNAs, and overlapping transcripts. Altogether, we detected 875 transcripts, of which 759 are novel and 116 have been annotated previously. These RNA molecules include 41 novel putative protein coding transcript (each containing 5’-truncated in-frame ORFs), 14 monocistronic transcripts, 99 multicistronic RNAs, 101 non-coding RNA, and 504 length isoforms. We also detected RNA methylation in 12 viral genes and RNA hyper-editing in the longer 5’-UTR transcript isoform of ORF 19 gene.

scholarly journals Genome sequence resource of Phomopsis longicolla strain YC2-1, a fungal pathogen causing Phomopsis stem blight in soybean

2021 ◽  
Author(s):  
Xiaolin Zhao ◽  
Zhichao Zhang ◽  
Sujiao Zheng ◽  
Wenwu Ye ◽  
Xiaobo Zheng ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Stem Canker ◽  
Quality Data ◽  
Phomopsis Longicolla ◽  
Protein Coding ◽  
Stem Blight ◽  
A Genome ◽  
Long Read ◽  
Genomic Resource ◽  
Blight Disease

Diaporthe-Phomopsis disease complex causes considerable yield losses in soybean production worldwide. As one of the major pathogens, Phomopsis longicolla T. W. Hobbs (syn. Diaporthe longicolla) is not only the primary agent of Phomopsis seed decay, but also one of the agents of Phomopsis pod and stem blight, and Phomopsis stem canker. We performed both PacBio long read sequencing and Illumina short read sequencing, and obtained a genome assembly for the P. longicolla strain YC2-1, which was isolated from soybean stem with Phomopsis stem blight disease. The 63.1 Mb genome assembly contains 87 scaffolds, with a minimum, maximum, and N50 scaffold length of 20 kb, 4.6 Mb, and 1.5 Mb respectively, and a total of 17,407 protein-coding genes. The high-quality data expand the genomic resource of P. longicolla species and will provide a solid foundation for a better understanding of their genetic diversity and pathogenic mechanisms.

scholarly journals Chromosome-level assembly of Drosophila bifasciata reveals important karyotypic transition of the X chromosome

2019 ◽  
Author(s):  
Ryan Bracewell ◽  
Anita Tran ◽  
Kamalakar Chatla ◽  
Doris Bachtrog
Keyword(s):  
X Chromosome ◽  
Genome Assembly ◽  
De Novo ◽  
Pericentromeric Region ◽  
Species Group ◽  
Chromosome 15 ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Long Read ◽  
Chromosome Level

ABSTRACTThe Drosophila obscura species group is one of the most studied clades of Drosophila and harbors multiple distinct karyotypes. Here we present a de novo genome assembly and annotation of D. bifasciata, a species which represents an important subgroup for which no high-quality chromosome-level genome assembly currently exists. We combined long-read sequencing (Nanopore) and Hi-C scaffolding to achieve a highly contiguous genome assembly approximately 193Mb in size, with repetitive elements constituting 30.1% of the total length. Drosophila bifasciata harbors four large metacentric chromosomes and the small dot, and our assembly contains each chromosome in a single scaffold, including the highly repetitive pericentromere, which were largely composed of Jockey and Gypsy transposable elements. We annotated a total of 12,821 protein-coding genes and comparisons of synteny with D. athabasca orthologs show that the large metacentric pericentromeric regions of multiple chromosomes are conserved between these species. Importantly, Muller A (X chromosome) was found to be metacentric in D. bifasciata and the pericentromeric region appears homologous to the pericentromeric region of the fused Muller A-AD (XL and XR) of pseudoobscura/affinis subgroup species. Our finding suggests a metacentric ancestral X fused to a telocentric Muller D and created the large neo-X (Muller A-AD) chromosome ∼15 MYA. We also confirm the fusion of Muller C and D in D. bifasciata and show that it likely involved a centromere-centromere fusion.

scholarly journals Chromosome-scale assembly of the Sparassis latifolia genome obtained using long-read and Hi-C sequencing

2021 ◽  
Author(s):  
Chi yang ◽  
Lu Ma ◽  
Donglai Xiao ◽  
Xiaoyu Liu ◽  
Xiaoling Jiang ◽  
...  
Keyword(s):  
Repetitive Sequences ◽  
Draft Genome ◽  
Edible Mushroom ◽  
Illumina Hiseq ◽  
Protein Coding ◽  
Long Reads ◽  
Oxford Nanopore ◽  
Genome Features ◽  
Long Read ◽  
Genomic Studies

Sparassis latifolia is a valuable edible mushroom cultivated in China. In 2018, our research group reported an incomplete and low quality genome of S. latifolia was obtained by Illumina HiSeq 2500 sequencing. These limitations in the available genome have constrained genetic and genomic studies in this mushroom resource. Herein, an updated draft genome sequence of S. latifolia was generated by Oxford Nanopore sequencing and the Hi-C technique. A total of 8.24 Gb of Oxford Nanopore long reads representing ~198.08X coverage of the S. latifolia genome were generated. Subsequently, a high-quality genome of 41.41 Mb, with scaffold and contig N50 sizes of 3.31 Mb and 1.51 Mb, respectively, was assembled. Hi-C scaffolding of the genome resulted in 12 pseudochromosomes containing 93.56% of the bases in the assembled genome. Genome annotation further revealed that 17.47% of the genome was composed of repetitive sequences. In addition, 13,103 protein-coding genes were predicted, among which 98.72% were functionally annotated. BUSCO assay results further revealed that there were 92.07% complete BUSCOs. The improved chromosome-scale assembly and genome features described here will aid further molecular elucidation of various traits, breeding of S. latifolia, and evolutionary studies with related taxa.

scholarly journals Chromosome-Level Assembly of Drosophila bifasciata Reveals Important Karyotypic Transition of the X Chromosome

2020 ◽  
Vol 10 (3) ◽  
pp. 891-897 ◽  
Author(s):  
Ryan Bracewell ◽  
Anita Tran ◽  
Kamalakar Chatla ◽  
Doris Bachtrog
Keyword(s):  
X Chromosome ◽  
Genome Assembly ◽  
De Novo ◽  
Pericentromeric Region ◽  
Species Group ◽  
Chromosome 15 ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Long Read ◽  
Chromosome Level

The Drosophila obscura species group is one of the most studied clades of Drosophila and harbors multiple distinct karyotypes. Here we present a de novo genome assembly and annotation of D. bifasciata, a species which represents an important subgroup for which no high-quality chromosome-level genome assembly currently exists. We combined long-read sequencing (Nanopore) and Hi-C scaffolding to achieve a highly contiguous genome assembly approximately 193 Mb in size, with repetitive elements constituting 30.1% of the total length. Drosophila bifasciata harbors four large metacentric chromosomes and the small dot, and our assembly contains each chromosome in a single scaffold, including the highly repetitive pericentromeres, which were largely composed of Jockey and Gypsy transposable elements. We annotated a total of 12,821 protein-coding genes and comparisons of synteny with D. athabasca orthologs show that the large metacentric pericentromeric regions of multiple chromosomes are conserved between these species. Importantly, Muller A (X chromosome) was found to be metacentric in D. bifasciata and the pericentromeric region appears homologous to the pericentromeric region of the fused Muller A-AD (XL and XR) of pseudoobscura/affinis subgroup species. Our finding suggests a metacentric ancestral X fused to a telocentric Muller D and created the large neo-X (Muller A-AD) chromosome ∼15 MYA. We also confirm the fusion of Muller C and D in D. bifasciata and show that it likely involved a centromere-centromere fusion.

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