scholarly journals Dicyemid Mesozoans: A Unique Parasitic Lifestyle and a Reduced Genome

2019 ◽  
Vol 11 (8) ◽  
pp. 2232-2243 ◽  
Author(s):  
Tsai-Ming Lu ◽  
Miyuki Kanda ◽  
Hidetaka Furuya ◽  
Noriyuki Satoh
Keyword(s):  
Molecular Mechanisms ◽  
Hox Genes ◽  
Transcriptome Assembly ◽  
Repetitive Sequences ◽  
Protein Coding ◽  
Animal Group ◽  
Kegg Pathways ◽  
Genome Features ◽  
Parasitic Lifestyle ◽  
Mixed Stage

Abstract Dicyemids, previously called “mesozoans” (intermediates between unicellular protozoans and multicellular metazoans), are an enigmatic animal group. They have a highly simplified adult body, comprising only ∼30 cells, and they have a unique parasitic lifestyle. Recently, dicyemids were shown to be spiralians, with affinities to the Platyhelminthes. In order to understand molecular mechanisms involved in evolution of this odd animal, we sequenced the genome of Dicyema japonicum and a reference transcriptome assembly using mixed-stage samples. The D. japonicum genome features a high proportion of repetitive sequences that account for 49% of the genome. The dicyemid genome is reduced to ∼67.5 Mb with 5,012 protein-coding genes. Only four Hox genes exist in the genome, with no clustering. Gene distribution in KEGG pathways shows that D. japonicum has fewer genes in most pathways. Instead of eliminating entire critical metabolic pathways, parasitic lineages likely simplify pathways by eliminating pathway-specific genes, while genes with fundamental functions may be retained in multiple pathways. In principle, parasites can stand to lose genes that are unnecessary, in order to conserve energy. However, whether retained genes in incomplete pathways serve intermediate functions and how parasites overcome the physiological needs served by lost genes, remain to be investigated in future studies.

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 genome assembly of a butterflyfish, Chelmon rostratus

2019 ◽  
Author(s):  
Xiaoyun Huang ◽  
Yue Song ◽  
Suyu Zhang ◽  
A Yunga ◽  
Mengqi Zhang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Repetitive Sequences ◽  
Ecological Environment ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
A Genome ◽  
Genome Information ◽  
Adaptation Evolution ◽  
Core Genes ◽  
Chromosome Level

AbstractChelmon rostratus (Teleostei, Perciformes, Chaetodontidae) is a copperband butterflyfish. As an ornamental fish, the genome information for this species might help understanding the genome evolution of Chaetodontidae and adaptation/evolution of coral reef fish.In this study, using the stLFR co-Barcode reads data, we assembled a genome of 638.70 Mb in size with contig and scaffold N50 sizes of 294.41 kb and 2.61 Mb, respectively. 94.40% of scaffold sequences were assigned to 24 chromosomes using Hi-C data and BUSCO analysis showed that 97.3% (2,579) of core genes were found in our assembly. Up to 21.47 % of the genome was found to be repetitive sequences and 21,375 protein-coding genes were annotated. Among these annotated protein-coding genes, 20,163 (94.33%) proteins were assigned with possible functions.As the first genome for Chaetodontidae family, the information of these data helpfully to improve the essential to the further understanding and exploration of marine ecological environment symbiosis with coral and the genomic innovations and molecular mechanisms contributing to its unique morphology and physiological features.

scholarly journals Full-length transcriptome assembly of Andrias davidianus (Amphibia: Caudata) skin via hybrid sequencing

2021 ◽  
Author(s):  
Yu Bai ◽  
Yonglu Meng ◽  
Jianlin Luo ◽  
Hui Wang ◽  
Guoyong Li ◽  
...  
Keyword(s):  
Transcriptome Assembly ◽  
Terrestrial Ecosystems ◽  
Full Length ◽  
Amphibian Species ◽  
Protein Coding ◽  
Important Species ◽  
Genetic Characteristics ◽  
Andrias Davidianus ◽  
Kegg Pathways ◽  
Complex Adaptive

The Chinese giant salamander, Andrias davidianus, is the largest amphibian species in the world; it is thus an economically and ecologically important species. The skin of A. davidianus exhibits complex adaptive structural and functional adaptations to facilitate survival in aquatic and terrestrial ecosystems. Here, we report the first full-length amphibian transcriptome from the dorsal skin of A. davidianus, which was assembled using hybrid sequencing and the PacBio and Illumina platforms. A total of 153,038 transcripts were hybrid assembled (mean length of 2,039 bp and N50 of 2,172 bp), and 133,794 were annotated in at least one database (nr, Swiss-Prot, KEGG, KOGs, GO, and nt). A total of 58,732, 68,742, and 115,876 transcripts were classified into 24 KOG categories, 1,903 GO term categories, and 46 KEGG pathways (level 2), respectively. A total of 207,627 protein-coding regions, 785 transcription factors, 27,237 potential long non-coding RNAs, and 8,299 simple sequence repeats were also identified. The hybrid-assembled transcriptome recovered more full-length transcripts, had a higher N50 contig length, and a higher annotation rate of unique genes compared with that assembled in previous studies using next-generation sequencing. The high-quality full-length reference gene set generated in this study will help elucidate the genetic characteristics of A. davidianus skin and aid the identification of functional skin proteins.

scholarly journals De novo transcriptome assembly of the Italian white truffle (Tuber magnatum Pico)

2018 ◽  
Author(s):  
Federico Vita ◽  
Amedeo Alpi ◽  
Edoardo Bertolini
Keyword(s):  
Molecular Mechanisms ◽  
De Novo ◽  
Transcriptome Assembly ◽  
Rna Seq ◽  
Genetic Studies ◽  
Protein Coding ◽  
Important Species ◽  
White Truffle ◽  
Tuber Magnatum ◽  
Insight Into

AbstractThe Italian white truffle (Tuber magnatum Pico) is a gastronomic delicacy that dominates the worldwide truffle market. Despite its importance, the genomic resources currently available for this species are still limited. Here we present the first de novo transcriptome assembly of T. magnatum. Illumina RNA-seq data were assembled using a single-k-mer approach into 22,932 transcripts with N50 of 1,524 bp. Our approach allowed to predict and annotate 12,367 putative protein coding sequences, reunited in 6,723 loci. In addition, we identified 2,581 gene-based SSR markers. This work provides the first publicly available reference transcriptome for genomics and genetic studies providing insight into the molecular mechanisms underlying the biology of this important species.

scholarly journals De Novo Transcriptome Assembly of Isatis indigotica at Reproductive Stages and Identification of Candidate Genes Associated with Flowering Pathways

2018 ◽  
Vol 143 (1) ◽  
pp. 56-66
Author(s):  
Yu Bai ◽  
Ying Zhou ◽  
Xiaoqing Tang ◽  
Yu Wang ◽  
Fangquan Wang ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Transcriptome Assembly ◽  
Orthologous Group ◽  
Rna Seq ◽  
Isatis Indigotica ◽  
Regulatory Pathways ◽  
Kegg Pathways ◽  
Bolting And Flowering

The appropriate timing of bolting and flowering is one of the keys to the reproductive success of Isatis indigotica. Several flowering regulatory pathways have been reported in plant species, but we know little about flowering regulatory in I. indigotica. In the present study, we performed RNA-seq and annotated I. indigotica transcriptome using RNA from five tissues (leaves, roots, flowers, fruit, and stems). Illumina sequencing generated 149,907,857 high-quality clean reads and 124,508 unigenes were assembled from the sequenced reads. Of these unigenes, 88,064 were functionally annotated by BLAST searches against the public protein databases. Functional classification and annotation assigned 55,991 and 23,072 unigenes to 52 gene ontology (GO) terms and 25 clusters of orthologous group (COG) categories, respectively. A total of 19,927 unigenes were assigned to 124 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and 80 candidate genes related to plant circadian rhythm were identified. We also identified a number of differentially expressed genes (DEG) and 91 potential bolting and flowering-related genes from the RNA-seq data. This study is the first to identify bolting and flowering-related genes based on transcriptome sequencing and assembly in I. indigotica. The results provide foundations for the exploration of flowering pathways in I. indigotica and investigations of the molecular mechanisms of bolting and flowering in Brassicaceae plants.

scholarly journals Transcriptome analysis ofPolygonum minusreveals candidate genes involved in important secondary metabolic pathways of phenylpropanoids and flavonoids

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2938 ◽  
Author(s):  
Kok-Keong Loke ◽  
Reyhaneh Rahnamaie-Tajadod ◽  
Chean-Chean Yeoh ◽  
Hoe-Han Goh ◽  
Zeti-Azura Mohamed-Hussein ◽  
...  
Keyword(s):  
Secondary Metabolite ◽  
Molecular Mechanisms ◽  
Transcriptome Assembly ◽  
Transcript Abundance ◽  
The Public ◽  
Kegg Pathways ◽  
Leaf Tissues ◽  
Polygonum Minus ◽  
Medicinal Properties ◽  
Root Tissues

BackgroundPolygonum minusis an herbal plant in the Polygonaceae family which is rich in ethnomedicinal plants. The chemical composition and characteristic pungent fragrance ofPolygonum minushave been extensively studied due to its culinary and medicinal properties. There are only a few transcriptome sequences available for species from this important family of medicinal plants. The limited genetic information from the public expressed sequences tag (EST) library hinders further study on molecular mechanisms underlying secondary metabolite production.MethodsIn this study, we performed a hybrid assembly of 454 and Illumina sequencing reads fromPolygonum minusroot and leaf tissues, respectively, to generate a combined transcriptome library as a reference.ResultsA total of 34.37 million filtered and normalized reads were assembled into 188,735 transcripts with a total length of 136.67 Mbp. We performed a similarity search against all the publicly available genome sequences and found similarity matches for 163,200 (86.5%) ofPolygonum minustranscripts, largely fromArabidopsis thaliana(58.9%). Transcript abundance in the leaf and root tissues were estimated and validated through RT-qPCR of seven selected transcripts involved in the biosynthesis of phenylpropanoids and flavonoids. All the transcripts were annotated against KEGG pathways to profile transcripts related to the biosynthesis of secondary metabolites.DiscussionThis comprehensive transcriptome profile will serve as a useful sequence resource for molecular genetics and evolutionary research on secondary metabolite biosynthesis in Polygonaceae family. Transcriptome assembly ofPolygonum minuscan be accessed athttp://prims.researchfrontier.org/index.php/dataset/transcriptome.

scholarly journals RNA-Seq analysis and transcriptome assembly of Salicornia neei reveals a powerful system for ammonium detoxification

2021 ◽  
Author(s):  
Mónica Díaz-Silva ◽  
Jonathan Maldonado ◽  
Nicol Delgado ◽  
Pamela Veloso ◽  
Herman Silva ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
De Novo ◽  
Saline Water ◽  
Transcriptome Assembly ◽  
Glutamate Synthase ◽  
Ammonium Uptake ◽  
Saline Wastewater ◽  
Anatomical Entity ◽  
Kegg Pathways ◽  
Pathway Analyses

ABSTRACTBackgroundSalicornia neei is a halophyte plant that has been proposed for phytoremediation of saline wastewater generated by land-based aquaculture, which usually contains elevated concentrations of ammonium resulting from protein metabolism. To identify the molecular mechanisms related to ammonium response through of analysis results in silico and the Michaelis–Menten ammonium removal biokinetics and the transcriptome of S. neei in response to growth in saline water containing 3 mM ammonium.ResultsThe parameters for ammonium uptake by S. neei root cuttings were estimated: 1) maximum uptake rate Imax = 7.07 ± 0.27 mM N g−1 fresh weight h−1; and 2) half-saturation constant Km = 0.85 ± 0.12 mM N L−1. Further, a total of 45,327 genes were annotated, which represents 51.2% of the contig predicted from de novo assembly. A total of 9,140 genes were differentially expressed in response to ammonium in saline water, but only 7,396 could be annotated against functional databases. According to the GO enrichment and as well as KEGG pathway analyses showed these upregulated genes were involved in pr cellular anatomical entity, cellular process, and metabolic process, including biological KEGG pathways linked to biosynthesis amino acid biosynthesis, nitrogen metabolism and autophagy and other. In addiction, a set of 72 genes were directly involved in ammonium metabolism, including glutamine synthetase 1 (GLN1), glutamate synthase 1 (GLT1), and ferredoxin-dependent glutamate synthase chloroplastic (Fd-GOGAT).ConclusionOur results support the hypothesis that an ammonium detoxification system mediated by glutamine and glutamate synthase was activated in S. neei when exposed to ammonium and saline water. These results provide novel insight into understanding the molecular mechanisms of ammonium nutrition and aid for investigating the response of halophyte plants to saline wastewater from land-based aquaculture

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

Abstract 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 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 Combined genomic, transcriptomic, and metabolomic analyses provide insights into chayote (Sechium edule) evolution and fruit development

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Anzhen Fu ◽  
Qing Wang ◽  
Jianlou Mu ◽  
Lili Ma ◽  
Changlong Wen ◽  
...  
Keyword(s):  
Fruit Development ◽  
Repetitive Sequences ◽  
Genetic Research ◽  
Future Research ◽  
Agricultural Crop ◽  
Protein Coding ◽  
Third Generation Sequencing ◽  
Sechium Edule ◽  
Generation Sequencing ◽  
Cucurbitaceae Family

AbstractChayote (Sechium edule) is an agricultural crop in the Cucurbitaceae family that is rich in bioactive components. To enhance genetic research on chayote, we used Nanopore third-generation sequencing combined with Hi–C data to assemble a draft chayote genome. A chromosome-level assembly anchored on 14 chromosomes (N50 contig and scaffold sizes of 8.40 and 46.56 Mb, respectively) estimated the genome size as 606.42 Mb, which is large for the Cucurbitaceae, with 65.94% (401.08 Mb) of the genome comprising repetitive sequences; 28,237 protein-coding genes were predicted. Comparative genome analysis indicated that chayote and snake gourd diverged from sponge gourd and that a whole-genome duplication (WGD) event occurred in chayote at 25 ± 4 Mya. Transcriptional and metabolic analysis revealed genes involved in fruit texture, pigment, flavor, flavonoids, antioxidants, and plant hormones during chayote fruit development. The analysis of the genome, transcriptome, and metabolome provides insights into chayote evolution and lays the groundwork for future research on fruit and tuber development and genetic improvements in chayote.

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.

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