scholarly journals A NEW CASE OF DIPLOIDY WITHIN A HAPLOID GENUS OF ENTOMOPATHOGENIC FUNGI

2021 ◽  
Author(s):  
Knud Nor Nielsen ◽  
João Felipe Moreira Salgado ◽  
Myrsini Eirini Natsopoulou ◽  
Jason E Stajich ◽  
Henrik H. De Fine Licht
Keyword(s):  
Single Molecule ◽  
Fitness Landscape ◽  
Plant Root ◽  
Pathogenic Fungus ◽  
Past Research ◽  
Sexual Cycle ◽  
Single Nucleotide ◽  
Ploidy Levels ◽  
Metarhizium Acridum ◽  
Ascomycete Fungi

Fungi in the genus Metarhizium are soil-borne plant-root endophytes and rhizosphere colonisers, but also potent insect pathogens with highly variable host ranges. These ascomycete fungi are predominantly asexually reproducing and ancestrally haploid, but two independent origins of persistent diploidy within the Coleoptera-infecting M. majus species complex are known and has been attributed to incomplete chromosomal segregation following meiosis during the sexual cycle. There is also evidence for infrequent sexual cycles in the locust-specific pathogenic fungus Metarhizium acridum (Hypocreales: Clavicipitaceae), which is an important entomopathogenic biocontrol agent used for the control of grasshoppers in agricultural systems as an alternative to chemical control. Here, we show that the genome of the M. acridum isolate ARSEF 324, which is formulated and commercially utilised under the name Green Guard, is functionally diploid. We used single-molecule real-time (SMRT) sequencing technology to complete a high-quality assembly of ARSEF 324. Kmer frequencies, intragenomic collinearity between contigs and single nucleotide variant read depths across the genome revealed the first incidence of diploidy described within the species M. acridum. The haploid assembly of 44.7 Mb consisting of 20.8% repetitive elements, which is the highest proportion described of any Metarhizium species. The genome assembly and the inferred diploid state, can shed light on past research on this strain and could fuel future investigation into the fitness landscape of aberrant ploidy levels, not least in the contest of biocontrol agents.

scholarly journals The rhizosphere-competent entomopathogen Metarhizium anisopliae expresses a specific subset of genes in plant root exudate

Microbiology ◽  
2011 ◽  
Vol 157 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Monica Pava-Ripoll ◽  
Claudia Angelini ◽  
Weiguo Fang ◽  
Sibao Wang ◽  
Francisco J. Posada ◽  
...  
Keyword(s):  
Metarhizium Anisopliae ◽  
Plant Root ◽  
Sexual Cycle ◽  
Metarhizium Acridum ◽  
Specific Subset ◽  
Plant Root Exudate ◽  
Matrix Cell ◽  
Rhizosphere Competence ◽  
Upregulated Genes ◽  
Plant Surfaces

Metarhizium anisopliae and Beauveria bassiana are ubiquitous insect pathogens and possible plant symbionts, as some strains are endophytic or colonize the rhizosphere. We evaluated 11 strains of M. anisopliae and B. bassiana, and two soil saprophytes (the non-rhizospheric Aspergillus niger and the rhizosphere-competent Trichoderma harzianum) for their ability to germinate in bean root exudates (REs). Our results showed that some generalist strains of M. anisopliae were as good at germinating in RE as T. harzianum, although germination rates of the specialized acridid pathogen Metarhizium acridum and the B. bassiana strains were significantly lower. At RE concentrations of <1 mg ml−1, M. anisopliae strain ARSEF 2575 showed higher germination rates than T. harzianum. Microarrays showed that strain 2575 upregulated 29 genes over a 12 h period in RE. A similar number of genes (21) were downregulated. Upregulated genes were involved in carbohydrate metabolism, lipid metabolism, cofactors and vitamins, energy metabolism, proteolysis, extracellular matrix/cell wall proteins, transport proteins, DNA synthesis, the sexual cycle and stress response. However, 41.3 % of the upregulated genes were hypothetical or orphan sequences, indicating that many previously uncharacterized genes have functions related to saprophytic survival. Genes upregulated in response to RE included the subtilisin Pr1A, which is also involved in pathogenicity to insects. However, the upregulated Mad2 adhesin specifically mediates adhesion to plant surfaces, demonstrating that M. anisopliae has genes for rhizosphere competence that are induced by RE.

scholarly journals Highly specific imaging of mRNA in single cells by target RNA-initiated rolling circle amplification

2017 ◽  
Vol 8 (5) ◽  
pp. 3668-3675 ◽  
Author(s):  
Ruijie Deng ◽  
Kaixiang Zhang ◽  
Yupeng Sun ◽  
Xiaojun Ren ◽  
Jinghong Li
Keyword(s):  
Single Molecule ◽  
Single Cells ◽  
Rolling Circle Amplification ◽  
Robust Method ◽  
Single Nucleotide ◽  
Rolling Circle ◽  
Target Rna

We report a robust method for the efficient imaging of mRNA with single-nucleotide and near-single-molecule resolution in single cells.

scholarly journals A Complete Genome Sequence of the Wood Stem Endophyte Bacillus velezensis BY6 Strain Possessing Plant Growth-Promoting and Antifungal Activities

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ping Zhang ◽  
Jian Diao ◽  
Guangqiang Xie ◽  
Ling Ma ◽  
Lihai Wang
Keyword(s):  
Secondary Metabolite ◽  
Single Molecule ◽  
Complete Genome ◽  
Pathogenic Fungus ◽  
Gc Content ◽  
Endophytic Bacterium ◽  
Gene Clusters ◽  
Bacillus Velezensis ◽  
Sequencing Platform ◽  
Plant Growth Promoting

An endophytic bacterium Bacillus velezensis BY6 was isolated from the wood stems of healthy Populus davidiana × P. alba var. pyramidalis (PdPap). The BY6 strain can inhibit pathogenic fungus Alternaria alternate in PdPap and promote growth of PdPap seedlings. In the present study, we used the Pacific Biosciences long-read sequencing platform, a single-molecule real-time (SMRT) technology for strain BY6, to perform complete genome sequencing. The genome size was 3,898,273 bp, the number of genes was 4,045, and the average GC content was 47.33%. A complete genome of strain BY6 contained 110 secondary metabolite gene clusters. Nine of the secondary metabolite gene clusters exhibited antifungal activity and promoted growth functions primarily involved in the synthesis of surfactin, bacteriocins, accumulated iron ions, and related antibiotics. Gene clusters provide genetic resources for biotechnology and genetic engineering, and enhance understanding of the relationship between microorganisms and plants.

scholarly journals Evolutionary origins of the emergent ST796 clone of vancomycin resistant Enterococcus faecium

2016 ◽  
Author(s):  
Andrew H Buultjens ◽  
Margaret M C Lam ◽  
Susan Ballard ◽  
Ian R Monk ◽  
Andrew A Mahony ◽  
...  
Keyword(s):  
Single Molecule ◽  
Enterococcus Faecium ◽  
Genomic Islands ◽  
Nucleotide Polymorphisms ◽  
Circular Chromosome ◽  
Single Nucleotide ◽  
Evolutionary Origins ◽  
Eastern Australia ◽  
Healthcare Environments ◽  
Vancomycin Resistant

From early 2012, a novel clone of vancomycin resistant Enterococcus faecium (assigned the multi locus sequence type ST796) was simultaneously isolated from geographically separate hospitals in south eastern Australia and New Zealand. Here we describe the complete genome sequence of Ef_aus0233, a representative ST796 E. faecium isolate. We used PacBio single molecule real-time sequencing to establish a high quality, fully assembled genome comprising a circular chromosome of 2,888,087 bp and five plasmids. Comparison of Ef_aus0233 to other E. faecium genomes shows Ef_aus0233 is a member of the epidemic hospital-adapted lineage and has evolved from an ST555-like ancestral progenitor by the accumulation or modification of five mosaic plasmids and five putative prophage, acquisition of two cryptic genomic islands, accrued chromosomal single nucleotide polymorphisms and a 80kb region of recombination, also gaining Tn1549 and Tn916, transposons conferring resistance to vancomycin and tetracycline respectively. The genomic dissection of this new clone presented here underscores the propensity of the hospital E. faecium lineage to change, presumably in response to the specialized conditions of hospital and healthcare environments.

Dipeptidase PEPDA is required for the conidiation pattern shift in Metarhizium acridum

2021 ◽  
Author(s):  
Juan Li ◽  
Xueling Su ◽  
Yueqing Cao ◽  
Yuxian Xia
Keyword(s):  
Amino Acids ◽  
Filamentous Fungi ◽  
Pathogenic Fungus ◽  
Digital Gene Expression ◽  
Hyphal Growth ◽  
Metarhizium Acridum ◽  
Key Enzyme ◽  
Hydrolysis Of ◽  
Microcycle Conidiation

Filamentous fungi conduct two types of conidiation, typical conidiation from mycelia and microcycle conidiation (MC). Fungal conidiation can shift between the two patterns, which involved a large number of genes in the regulation of this process. In this study, we investigated the role of a dipeptidase gene pepdA in conidiation pattern shift in Metarhizium acridum , which is upregulated in MC pattern compared to typical conidiation. Results showed that disruption of the pepdA resulted in a shift of conidiation pattern from MC to typical conidiation. Metabolomic analyses of amino acids showed that the levels of 19 amino acids significantly changed in Δ pepdA mutant. The defect of MC in Δ pepdA can be rescued when nonpolar amino acids, α-alanine, β-alanine or proline, were added into s ucrose y east extract a gar (SYA) medium. Digital gene expression profiling analysis revealed that PEPDA mediated transcription of sets of genes which were involved in hyphal growth and development, sporulation, cell division, and amino acid metabolism. Our results demonstrated that PEPDA played important roles in the regulation of MC by manipulating the levels of amino acids in M. acridum . IMPORTANCE Conidia, as the asexual propagules in many fungi, are start and end of fungal lifecycle. In entomopathogenic fungi, conidia are the infective form essential for their pathogenicity. Filamentous fungi conduct two types of conidiation, typical conidiation from mycelia and microcycle conidiation. The mechanisms of the shift between the two conidiation patterns remain to be elucidated. In this study, we demonstrated that the dipeptidase PEPDA, a key enzyme from the insect-pathogenic fungus Metarhizium acridum for the hydrolysis of dipeptides, is associated with a shift of conidiation pattern. The conidiation pattern of the Δ pepdA mutant was restored when supplemented with the nonpolar amino acids rather than polar amino acids. Therefore, this report highlights that the dipeptidase PEPDA regulates MC by manipulating the levels of amino acids in M. acridum.

scholarly journals Single-molecule detection of deoxyribonucleoside triphosphates in microdroplets

2019 ◽  
Vol 47 (17) ◽  
pp. e101-e101 ◽  
Author(s):  
Boris Breiner ◽  
Kerr Johnson ◽  
Magdalena Stolarek ◽  
Ana-Luisa Silva ◽  
Aurel Negrea ◽  
...  
Keyword(s):  
Dna Sequencing ◽  
Single Molecule ◽  
Dna Polymerases ◽  
Single Molecule Detection ◽  
Synthesis Methods ◽  
Single Nucleotide ◽  
New Approach ◽  
Fluorescent Signal ◽  
Single Molecule Level ◽  
Current Sequence

AbstractA new approach to single-molecule DNA sequencing in which dNTPs, released by pyrophosphorolysis from the strand to be sequenced, are captured in microdroplets and read directly could have substantial advantages over current sequence-by-synthesis methods; however, there is no existing method sensitive enough to detect a single nucleotide in a microdroplet. We have developed a method for dNTP detection based on an enzymatic two-stage reaction which produces a robust fluorescent signal that is easy to detect and process. By taking advantage of the inherent specificity of DNA polymerases and ligases, coupled with volume restriction in microdroplets, this method allows us to simultaneously detect the presence of and distinguish between, the four natural dNTPs at the single-molecule level, with negligible cross-talk.

scholarly journals Bottom-up single-molecule strategy for understanding subunit function of tetrameric β-galactosidase

2018 ◽  
Vol 115 (33) ◽  
pp. 8346-8351 ◽  
Author(s):  
Xiang Li ◽  
Yu Jiang ◽  
Shaorong Chong ◽  
David R. Walt
Keyword(s):  
Single Molecule ◽  
Wild Type ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Single Molecule Level ◽  
Subunit Function ◽  
Enzyme Molecules ◽  
Individual Enzyme ◽  
Kinetics Of

In this paper, we report an example of the engineered expression of tetrameric β-galactosidase (β-gal) containing varying numbers of active monomers. Specifically, by combining wild-type and single-nucleotide polymorphism plasmids at varying ratios, tetrameric β-gal was expressed in vitro with one to four active monomers. The kinetics of individual enzyme molecules revealed four distinct populations, corresponding to the number of active monomers in the enzyme. Using single-molecule-level enzyme kinetics, we were able to measure an accurate in vitro mistranslation frequency (5.8 × 10−4 per base). In addition, we studied the kinetics of the mistranslated β-gal at the single-molecule level.

scholarly journals High-fidelity amplified FISH for the detection and allelic discrimination of single mRNA molecules

2019 ◽  
Vol 116 (28) ◽  
pp. 13921-13926 ◽  
Author(s):  
Salvatore A. E. Marras ◽  
Yuri Bushkin ◽  
Sanjay Tyagi
Keyword(s):  
Single Molecule ◽  
Hybridization Chain Reaction ◽  
Wild Type ◽  
Allelic Discrimination ◽  
Single Nucleotide ◽  
Tissue Sections ◽  
Powerful Approach ◽  
Probe System ◽  
Single Nucleotide Variations

Amplification of signals by the hybridization chain reaction (HCR) is a powerful approach for increasing signal strength in single-molecule fluorescence in situ hybridization, but probes tagged with an HCR initiator sequence are prone to producing false signals. Here we describe a system of interacting hairpin binary probes in which the HCR initiator sequence is conditionally sequestered. The binding of these probes to a perfectly complementary target unmasks the initiator, enabling the generation of an amplified signal. This probe system can distinguish single-nucleotide variations within single mRNA molecules and produces amplified signals in situ for both mutant and wild-type variants, each in a distinguishable color. This technology will augment studies of imbalanced allelic expression and will be useful for the detection of somatic mutations in cancer biopsies. By tiling these probes along the length of an mRNA target, enhanced signals can be obtained, thereby enabling the scanning of tissue sections for gene expression utilizing lower magnification microscopy, overcoming tissue autofluorescence, and allowing the detection of low-abundance biomarkers in flow cytometry.

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