Efficient four fragment cloning for the construction of vectors for targeted gene replacement in filamentous fungi
TL;DR: The new vectors designed for USER Friendly cloning provided a fast reliable method to construct vectors for targeted gene manipulations in fungi.
Abstract: The rapid increase in whole genome fungal sequence information allows large scale functional analyses of target genes. Efficient transformation methods to obtain site-directed gene replacement, targeted over-expression by promoter replacement, in-frame epitope tagging or fusion of coding sequences with fluorescent markers such as GFP are essential for this process. Construction of vectors for these experiments depends on the directional cloning of two homologous recombination sequences on each side of a selection marker gene. Here, we present a USER Friendly cloning based technique that allows single step cloning of the two required homologous recombination sequences into different sites of a recipient vector. The advantages are: A simple experimental design, free choice of target sequence, few procedures and user convenience. The vectors are intented for Agrobacterium tumefaciens and protoplast based transformation technologies. The system has been tested by the construction of vectors for targeted replacement of 17 genes and overexpression of 12 genes in Fusarium graminearum. The results show that four fragment vectors can be constructed in a single cloning step with an average efficiency of 84% for gene replacement and 80% for targeted overexpression. The new vectors designed for USER Friendly cloning provided a fast reliable method to construct vectors for targeted gene manipulations in fungi.
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12 Jul 2019
TL;DR: Gene expression of the two major secreted acid proteases was barely affected in the ΔprtT deletant during infection of citrus fruit, and no conclusion could be drawn on the role of these secreted acidic proteases on the virulence of P. digitatum.
Abstract: Penicillium digitatum is the major postharvest pathogen of citrus fruit under Mediterranean climate conditions. Previous results have shown that proteases is the largest enzyme family induced by P. digitatum during fruit infection. In the present work, we addressed the study of the role of P. digitatum’s proteases in virulence following two complementary approaches. In the first approach, we undertook the functional characterization of the P. digitatum prtT gene, which codes for a putative transcription factor previously shown to regulate extracellular proteases in other filamentous fungi. Deletion of prtT caused a significant loss in secreted protease activity during in vitro growth assays. However, there was no effect on virulence. Gene expression of the two major secreted acid proteases was barely affected in the ΔprtT deletant during infection of citrus fruit. Hence, no conclusion could be drawn on the role of these secreted acidic proteases on the virulence of P. digitatum. In the second approach, we studied the effect of different protease inhibitors and chelators on virulence. Co-inoculation of citrus fruit with P. digitatum conidia and a cocktail of protease inhibitors resulted in almost a complete absence of disease development. Analysis of individual inhibitors revealed that the metalloprotease inhibitor, 1,10-phenanthroline, was responsible for the observed effect. The application of metal ions reverted the protective effect caused by the metallopeptidase inhibitor. These results may set the basis for the development of new alternative treatments to combat this important postharvest pathogen.
13 citations
TL;DR: The predominant role of the PdCYP51B enhancer is suggested in the acquisition of DMI resistance and fungal virulence, by replacing homologues genes with same putative function.
13 citations
Patent•
03 Feb 2016
TL;DR: In this article, surfaces for de novo nucleic acid synthesis which provide low error rates were provided, and methods and devices were provided to increase the nucleic acids mass yield resulting from de nov nucleomic acid synthesis.
Abstract: Methods and devices are provided herein for surfaces for de novo nucleic acid synthesis which provide for low error rates. In addition, methods and devices are provided herein for increased nucleic acid mass yield resulting from de novo nucleic acid synthesis.
13 citations
TL;DR: This study indicates that PdSlt2 MAPK is functionally preserved in P. digitatum and highlights the relevant role of the PdDSlt 2 MAP kinase-mediated signalling pathway in regulating diverse genes crucial for infection and asexual reproduction.
13 citations
Cites methods from "Efficient four fragment cloning for..."
...142 A plasmid derived from plasmid pRFHU2 (Frandsen et al. 2008) and containing the flanking 143 regions of the PdSlt2 gene surrounding the hygromycin resistance cassette in he T-DNA 144 region of the plasmid was constructed....
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Patent•
21 Apr 2016
TL;DR: In this paper, devices and methods for de novo synthesis of large and highly accurate libraries of oligonucleic acids are provided, which include structures having a main channel and micro-channel, where the micro-channels have a high surface area to volume ratio.
Abstract: Devices and methods for de novo synthesis of large and highly accurate libraries of oligonucleic acids are provided herein Devices include structures having a main channel and microchannels, where the microchannels have a high surface area to volume ratio Devices disclosed herein provide for de novo synthesis of oligonucleic acids having a low error rate
13 citations
References
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TL;DR: These procedures, which can circumvent the need for large-scale phage or plasmid growths, preparative gel-electrophoresis and the screening of molecular clones, can facilitate the rapid study of sequence-specific interactions of proteins and DNA.
Abstract: Specific, end-labeled DNA fragments can be simply and rapidly prepared using the polymerase chain reaction (PCR). Such fragments are suitable for use in DNase I protection footprint assays, chemical sequencing reactions, and for the production and analysis of paused RNA polymerase transcription complexes. Moreover, a general means of introducing a specific mutation at any position along the length of such PCR-generated fragments is described. These procedures, which can circumvent the need for large-scale phage or plasmid growths, preparative gel-electrophoresis and the screening of molecular clones, can facilitate the rapid study of sequence-specific interactions of proteins and DNA. A rapid means of removing excess oligonucleotide primers from completed PCRs is also described.
2,471 citations
"Efficient four fragment cloning for..." refers methods in this paper
...Several laboratories have solved this problem by dividing the replacement constructs into two, a technique known as bipartite gene-targeting or split-marker recombination [6- 8]. In this technique, the two HRS's are fused with two thirds of either the 3' or 5'end of the selection marker gene, by fusion-PCR [ 9 ]....
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TL;DR: Questions are addressed, including which evolutionary pressures led to gene clustering, why closely related species produce different profiles of secondary metabolites, and whether fungal genomics will accelerate the discovery of new pharmacologically active natural products.
Abstract: Much of natural product chemistry concerns a group of compounds known as secondary metabolites. These low-molecular-weight metabolites often have potent physiological activities. Digitalis, morphine and quinine are plant secondary metabolites, whereas penicillin, cephalosporin, ergotrate and the statins are equally well known fungal secondary metabolites. Although chemically diverse, all secondary metabolites are produced by a few common biosynthetic pathways, often in conjunction with morphological development. Recent advances in molecular biology, bioinformatics and comparative genomics have revealed that the genes encoding specific fungal secondary metabolites are clustered and often located near telomeres. In this review, we address some important questions, including which evolutionary pressures led to gene clustering, why closely related species produce different profiles of secondary metabolites, and whether fungal genomics will accelerate the discovery of new pharmacologically active natural products.
1,488 citations
"Efficient four fragment cloning for..." refers background in this paper
...The use of Proofreading DNA polymerase is essential when making targeted genome modifications in fungi, due to the close spacing of fungal genes [26], which often means that the HRS extends into neighbouring genes or their regulatory sequences....
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TL;DR: A new procedure has been developed for the efficient cloning of complex PCR mixtures, resulting in libraries exclusively consisting of recombinant clones, and the procedure is applied for the cloning of inter-ALU fragments from hybrid cell-lines and human cosmid clones.
Abstract: A new procedure has been developed for the efficient cloning of complex PCR mixtures, resulting in libraries exclusively consisting of recombinant clones. Recombinants are generated between PCR products and a PCR-amplified plasmid vector. The procedure does not require the use of restriction enzymes, T4 DNA ligase or alkaline phosphatase. The 5'-ends of the primers used to generate the cloneable PCR fragments contain an additional 12 nucleotide (nt) sequence lacking dCMP. As a result, the amplification products include 12-nt sequences lacking dGMP at their 3'-ends. The 3'-terminal sequence can be removed by the action of the (3'----5') exonuclease activity of T4 DNA polymerase in the presence of dGTP, leading to fragments with 5'-extending single-stranded (ss) tails of a defined sequence and length. Similarly, the entire plasmid vector is amplified with primers homologous to sequences in the multiple cloning site. The vector oligos have additional 12-nt tails complementary to the tails used for fragment amplification, permitting the creation of ss-ends with T4 DNA polymerase in the presence of dCTP. Circularization can occur between vector molecules and PCR fragments as mediated by the 12-nt cohesive ends, but not in mixtures lacking insert fragments. The resulting circular recombinant molecules do not require in vitro ligation for efficient bacterial transformation. We have applied the procedure for the cloning of inter-ALU fragments from hybrid cell-lines and human cosmid clones.
1,185 citations
"Efficient four fragment cloning for..." refers methods in this paper
...Examples are the Xi-cloning, InFusion cloning, Ligase independent cloning (LIC-PCR), Recombinational cloning and USER Friendly cloning techniques [16-20]....
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TL;DR: This study describes a method for rapidly creating knockout mutants in which it makes use of yeast recombinational cloning, Neurospora mutant strains deficient in nonhomologous end-joining DNA repair, custom-written software tools, and robotics.
Abstract: The low rate of homologous recombination exhibited by wild-type strains of filamentous fungi has hindered development of high-throughput gene knockout procedures for this group of organisms. In this study, we describe a method for rapidly creating knockout mutants in which we make use of yeast recombinational cloning, Neurospora mutant strains deficient in nonhomologous end-joining DNA repair, custom-written software tools, and robotics. To illustrate our approach, we have created strains bearing deletions of 103 Neurospora genes encoding transcription factors. Characterization of strains during growth and both asexual and sexual development revealed phenotypes for 43% of the deletion mutants, with more than half of these strains possessing multiple defects. Overall, the methodology, which achieves high-throughput gene disruption at an efficiency >90% in this filamentous fungus, promises to be applicable to other eukaryotic organisms that have a low frequency of homologous recombination.
1,074 citations
"Efficient four fragment cloning for..." refers background or methods in this paper
...crassa, Colot and coworks [1], also allows for efficient four fragment cloning....
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...Contrary to Saccharomyces cerevisiae, where 30 bp is sufficient, many filamentous fungi require longer HRS [1], eg Fusarium graminearum needs 400 bp [2] 1500 bp is reported for Aspergillus niger [3] and around 1000 bp for Neurospora crassa [4]....
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...Vector construction for targeted replacement of genes is reduced to design of two primer pairs, which will permit automation of the experimental design as required for high-throughput knockout projects [1]....
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...Recombinational cloning of the two required HRS with a selection marker gene and a vector backbone is carried out in yeast, followed by PCR amplification of the two HRS and selection marker gene [1]....
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TL;DR: It is reported that A. tumefaciens can also transfer its T-DNA efficiently to the filamentous fungus Aspergillus awamori, demonstrating DNA transfer between a prokaryote and a filamentous fungi.
Abstract: Agrobacterium tumefaciens transfers part of its Ti plasmid, the T-DNA, to plant cells during tumorigenesis. It is routinely used for the genetic modification of a wide range of plant species. We report that A. tumefaciens can also transfer its T-DNA efficiently to the filamentous fungus Aspergillus awamori, demonstrating DNA transfer between a prokaryote and a filamentous fungus. We transformed both protoplasts and conidia with frequencies that were improved up to 600-fold as compared with conventional techniques for transformation of A. awamori protoplasts. The majority of the A. awamori transformants contained a single T-DNA copy randomly integrated at a chromosomal locus. The T-DNA integrated into the A. awamori genome in a manner similar to that described for plants. We also transformed a variety of other filamentous fungi, including Aspergillus niger, Fusarium venenatum, Trichoderma reesei, Colletotrichum gloeosporioides, Neurospora crassa, and the mushroom Agaricus bisporus, demonstrating that transformation using A. tumefaciens is generally applicable to filamentous fungi.
893 citations
"Efficient four fragment cloning for..." refers background in this paper
...The Agrobacterium tumefaciens mediated transformation (ATMT) technology [10] has the advantage of being independent of protoplast formation and can be used directly on a wide variety of fungal species and tissue types [11]....
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