scholarly journals The chromosome-scale genome resource for two endophytic Fusarium species: F. culmorum and F. pseudograminearum

Author(s):  
Xiaoliang Shan ◽  
Ying Zhu ◽  
Regina Redman ◽  
Russell Rodriguez ◽  
Zhilin Yuan

The genus Fusarium (Ascomycota, Hypocreales, Nectriaceae) includes many economically important plant pathogens, which cause devastating diseases of a wide range of crops and trees. Interestingly, there is increasing evidence that some Fusarium species also live as endophytes and benefit plant growth and stress tolerance. In this work, we sequence the whole genomes of endophytic F. culmorum and F. pseudograminearum, isolated from a coastal dunegrass (Leymus mollis), using long-read SMRT (single-molecule real-time) sequencing technology (PacBio). Their genomes are assembled into four chromosomes and a mitochondrial genome with a total assembly size of 40.05 M and 42.90 M, respectively. This resource should not only facilitate the functional studies designed to better understand what makes the two Fusarium species such successful plant beneficial fungus, but also reveal their genome evolution and adaptation.

2019 ◽  
Vol 47 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Yann Fichou ◽  
Isabelle Berlivet ◽  
Gaëlle Richard ◽  
Christophe Tournamille ◽  
Lilian Castilho ◽  
...  

Background: In the novel era of blood group genomics, (re-)defining reference gene/allele sequences of blood group genes has become an important goal to achieve, both for diagnostic and research purposes. As novel potent sequencing technologies are available, we thought to investigate the variability encountered in the three most common alleles of ACKR1, the gene encoding the clinically relevant Duffy antigens, at the haplotype level by a long-read sequencing approach. Materials and Methods: After long-range PCR amplification spanning the whole ACKR1 gene locus (∼2.5 kilobases), amplicons generated from 81 samples with known genotypes were sequenced in a single read by using the Pacific Biosciences (PacBio) single molecule, real-time (SMRT) sequencing technology. Results: High-quality sequencing reads were obtained for the 162 alleles (accuracy >0.999). Twenty-two nucleotide variations reported in databases were identified, defining 19 haplotypes: four, eight, and seven haplotypes in 46 ACKR1*01, 63 ACKR1*02, and 53 ACKR1*02N.01 alleles, respectively. Discussion: Overall, we have defined a subset of reference alleles by third-generation (long-read) sequencing. This technology, which provides a “longitudinal” overview of the loci of interest (several thousand base pairs) and is complementary to the second-generation (short-read) next-generation sequencing technology, is of critical interest for resolving novel, rare, and null alleles.


2020 ◽  
Author(s):  
Radwa A. Hanafy ◽  
Britny Johnson ◽  
Noha H. Youssef ◽  
Mostafa S. Elshahed

AbstractThe anaerobic gut fungi (AGF, Neocallimastigomycota) reside in the alimentary tracts of herbivores where they play a central role in the breakdown of ingested plant material. Accurate assessment of AGF diversity has been hampered by inherent deficiencies of the internal transcribed spacer1 (ITS1) region as a phylogenetic marker. Here, we report on the development and implementation of the D1/D2 region of the large ribosomal subunit (D1/D2 LSU) as a novel marker for assessing AGF diversity in culture-independent surveys. Sequencing a 1.4-1.5 Kbp amplicon encompassing the ITS1-5.8S rRNA-ITS2-D1/D2 LSU region in the ribosomal RNA locus from fungal strains and environmental samples generated a reference D1/D2 LSU database for all cultured AGF genera, as well as the majority of candidate genera encountered in prior ITS1-based diversity surveys. Subsequently, a D1/D2 LSU-based diversity survey using long read PacBio SMRT sequencing technology was conducted on fecal samples from 21 wild and domesticated herbivores. Twenty-eight genera and candidate genera were identified in the 17.7 K sequences obtained, including multiple novel lineages that were predominantly, but not exclusively, identified in wild herbivores. Association between certain AGF genera and animal lifestyles, or animal host family was observed. Finally, to address the current paucity of AGF isolates, concurrent isolation efforts utilizing multiple approaches to maximize recovery yielded 216 isolates belonging to twelve different genera, several of which have no prior cultured-representatives. Our results establish the utility of D1/D2 LSU and PacBio sequencing for AGF diversity surveys, and the culturability of a wide range of AGF taxa, and demonstrate that wild herbivores represent a yet-untapped reservoir of AGF diversity.


2021 ◽  
Vol 22 (18) ◽  
pp. 9888
Author(s):  
Lakshmipriya Perincherry ◽  
Monika Urbaniak ◽  
Izabela Pawłowicz ◽  
Karolina Kotowska ◽  
Agnieszka Waśkiewicz ◽  
...  

Fusarium species are common plant pathogens that cause several important diseases. They produce a wide range of secondary metabolites, among which mycotoxins and extracellular cell wall-degrading enzymes (CWDEs) contribute to weakening and invading the host plant successfully. Two species of Fusarium isolated from peas were monitored for their expression profile of three cell wall-degrading enzyme coding genes upon culturing with extracts from resistant (Sokolik) and susceptible (Santana) pea cultivars. The extracts from Santana induced a sudden increase in the gene expression, whereas Sokolik elicited a reduced expression. The coherent observation was that the biochemical profile of the host plant plays a major role in regulating the fungal gene expression. In order to uncover the fungal characteristics in planta, both pea cultivars were infected with two strains each of F. proliferatum and F. oxysporum on the 30th day of growth. The enzyme activity assays from both roots and rhizosphere indicated that more enzymes were used for degrading the cell wall of the resistant host compared to the susceptible host. The most commonly produced enzymes were cellulase, β-glucosidase, xylanase, pectinase and lipase, where the pathogen selectively degraded the components of both the primary and secondary cell walls. The levels of beauvericin accumulated in the infected roots of both cultivars were also monitored. There was a difference between the levels of beauvericin accumulated in both the cultivars, where the susceptible cultivar had more beauvericin than the resistant one, showing that the plants susceptible to the pathogen were also susceptible to the toxin accumulation.


2017 ◽  
Vol 5 (5) ◽  
Author(s):  
Dóra Tombácz ◽  
Norbert Moldován ◽  
Zsolt Balázs ◽  
Zsolt Csabai ◽  
Michael Snyder ◽  
...  

ABSTRACT Porcine circovirus type 1 (PCV1) is a nonpathogenic circovirus, and a contaminant of the porcine kidney (PK-15) cell line. We present the complete and annotated genome sequence of strain Szeged of PCV1, determined by Pacific Biosciences RSII long-read sequencing platform.


2021 ◽  
Author(s):  
Amar Bahadur

Fusarium spp. is one of the most economically important plant pathogens causing a wide range of plant diseases with significant crop losses globally. Fusarium wilt is a major problem all over the world. Fusarium oxysporum, Fusarium solani, Fusarium fujikuroi are economic importance species in worldwide. Fusarium solani causing disease in many agriculturally crops and favored by high temperatures and warm moist soils. The fungus produces three types of asexual spores; microconidia, macroconidia and chlamydospores serve as propagules in infecting host plants and found endophytes and saprophytes. The color of the colony, length and shape of the macroconidia, the number shape of microconidia and the presence or absence of chlamydospores are key features for the differentiation of Fusarium species. Pathogens, forms over 100 formae speciales cause disease in dicot and monocot plant species and infecting a variety of hosts. Vegetative compatibility Groups (VCG) is used to differentiate their races. Resistant cultivars and bio-control agents (Trichoderma spp., and Psedomonas spp.) have been used to manage the disease.


2019 ◽  
Author(s):  
Sam Kovaka ◽  
Aleksey V. Zimin ◽  
Geo M. Pertea ◽  
Roham Razaghi ◽  
Steven L. Salzberg ◽  
...  

AbstractRNA sequencing using the latest single-molecule sequencing instruments produces reads that are thousands of nucleotides long. The ability to assemble these long reads can greatly improve the sensitivity of long-read analyses. Here we present StringTie2, a reference-guided transcriptome assembler that works with both short and long reads. StringTie2 includes new computational methods to handle the high error rate of long-read sequencing technology, which previous assemblers could not tolerate. It also offers the ability to work with full-length super-reads assembled from short reads, which further improves the quality of assemblies. On 33 short-read datasets from humans and two plant species, StringTie2 is 47.3% more precise and 3.9% more sensitive than Scallop. On multiple long read datasets, StringTie2 on average correctly assembles 8.3 and 2.6 times as many transcripts as FLAIR and Traphlor, respectively, with substantially higher precision. StringTie2 is also faster and has a smaller memory footprint than all comparable tools.


2021 ◽  
Author(s):  
Lingyun Liu ◽  
Ke Teng ◽  
Xifeng Fan ◽  
Hui Zhang ◽  
Chao Han ◽  
...  

Abstract Pennisetum setaceum ‘Rubrum’ is an ornamental herb with purple leaves, and it is widely used in the construction of landscaping. However, the current next generation sequencing (NGS) transcriptome information is not satisfactory mainly because of the enormous difficulty in obtaining full-length transcripts. What’s more, the molecular mechanisms of anthocyanin accumulation have not been thoroughly studied. In this study, we used PacBio full-length transcriptome sequencing combined with NGS sequencing technology to conduct transcriptome analysis on leaves showing different colors at different stages to clarify the molecular mechanism involved in the color change of P. setaceum ‘Rubrum’. A total of 280,413 full-length non-chimeric reads (FLNC) sequences were obtained based on single-molecule long-read sequencing technology. We obtained 140,633 high quality (HQ) transcripts and 2,683 low quality (LQ) transcripts and identified 5,352 alternative splicing (AS). In addition, a total of 93,066 ORFs, including 57,457 full open links and 2,910 lncRNA sequences were screened out. Furthermore, a total of 10,795 differentially expressed genes were identified. Gene ontology (GO) cluster and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed the underlying mechanism of anthocyanin accumulation. In this study, to our best knowledge, we provided the full-length transcriptome information of P. setaceum ‘Rubrum’ for the first time. The underlying mechanism of anthocyanin accumulation in P. setaceum ‘Rubrum’ was further discussed based on the newly generated transcriptome data. The information will not only facilitate the gene function studies but also pave the way for future breeding projects of Pennisetum setaceum .


2020 ◽  
Vol 15 (2) ◽  
pp. 165-172
Author(s):  
Chaithra Pradeep ◽  
Dharam Nandan ◽  
Arya A. Das ◽  
Dinesh Velayutham

Background: The standard approach for transcriptomic profiling involves high throughput short-read sequencing technology, mainly dominated by Illumina. However, the short reads have limitations in transcriptome assembly and in obtaining full-length transcripts due to the complex nature of transcriptomes with variable length and multiple alternative spliced isoforms. Recent advances in long read sequencing by the Oxford Nanopore Technologies (ONT) offered both cDNA as well as direct RNA sequencing and has brought a paradigm change in the sequencing technology to greatly improve the assembly and expression estimates. ONT enables molecules to be sequenced without fragmentation resulting in ultra-long read length enabling the entire genes and transcripts to be fully characterized. The direct RNA sequencing method, in addition, circumvents the reverse transcription and amplification steps. Objective: In this study, RNA sequencing methods were assessed by comparing data from Illumina (ILM), ONT cDNA (OCD) and ONT direct RNA (ODR). Methods: The sensitivity & specificity of the isoform detection was determined from the data generated by Illumina, ONT cDNA and ONT direct RNA sequencing technologies using Saccharomyces cerevisiae as model. Comparative studies were conducted with two pipelines to detect the isoforms, novel genes and variable gene length. Results: Mapping metrics and qualitative profiles for different pipelines are presented to understand these disruptive technologies. The variability in sequencing technology and the analysis pipeline were studied.


2016 ◽  
Vol 4 (1) ◽  
Author(s):  
J. C. Huguet-Tapia ◽  
Z. Peng ◽  
B. Yang ◽  
Z. Yin ◽  
S. Liu ◽  
...  

Xanthomonas oryzae pv. oryzae is the etiological agent of bacterial rice blight. Three distinct clades of X. oryzae pv. oryzae are known. We present the complete annotated genome of the African clade strain AXO194 using long-read single-molecule PacBio sequencing technology. The genome comprises a single chromosome of 4,674,975 bp and encodes for nine transcriptional activator-like (TAL) effectors. The approach and data presented in this announcement provide information for complex bacterial genome organization and the discovery of new virulence effectors, and they facilitate target characterization of TAL effectors.


2018 ◽  
Author(s):  
Danny E. Miller ◽  
Cynthia Staber ◽  
Julia Zeitlinger ◽  
R. Scott Hawley

ABSTRACTThe Drosophila genus is a unique group containing a wide range of species that occupy diverse ecosystems. In addition to the most widely studied species, Drosophila melanogaster, many other members in this genus also possess a well-developed set of genetic tools. Indeed, high-quality genomes exist for several species within the genus, facilitating studies of the function and evolution of cis-regulatory regions and proteins by allowing comparisons across at least 50 million years of evolution. Yet, the available genomes still fail to capture much of the substantial genetic diversity within the Drosophila genus. We have therefore tested protocols to rapidly and inexpensively sequence and assemble the genome from any Drosophila species using single-molecule sequencing technology from Oxford Nanopore. Here, we use this technology to present high-quality genome assemblies of 15 Drosophila species: 10 of the 12 originally sequenced Drosophila species (ananassae, erecta, mojavensis, persimilis, pseudoobscura, sechellia, simulans, virilis, willistoni, and yakuba), four additional species that had previously reported assemblies (biarmipes, bipectinata, eugracilis, and mauritiana), and one novel assembly (triauraria). Genomes were generated from an average of 29x depth-of-coverage data that after assembly resulted in an average contig N50 of 4.4 Mb. Subsequent alignment of contigs from the published reference genomes demonstrates that our assemblies could be used to close over 60% of the gaps present in the currently published reference genomes. Importantly, the materials and reagents cost for each genome was approximately $1,000 (USD). This study demonstrates the power and cost-effectiveness of long-read sequencing for genome assembly in Drosophila and provides a framework for the affordable sequencing and assembly of additional Drosophila genomes.


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