1
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Abraham LN, Oggenfuss U, Croll D. Population-level transposable element expression dynamics influence trait evolution in a fungal crop pathogen. mBio 2024; 15:e0284023. [PMID: 38349152 PMCID: PMC10936205 DOI: 10.1128/mbio.02840-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/22/2024] [Indexed: 03/14/2024] Open
Abstract
The rapid adaptive evolution of microbes is driven by strong selection pressure acting on genetic variation. How adaptive genetic variation is generated within species and how such variation influences phenotypic trait expression is often not well understood though. We focused on the recent activity of transposable elements (TEs) using deep population genomics and transcriptomics analyses of a fungal plant pathogen with a highly active content of TEs in the genome. Zymoseptoria tritici causes one of the most damaging diseases on wheat, with recent adaptation to the host and environment being facilitated by TE-associated mutations. We obtained genomic and RNA-sequencing data from 146 isolates collected from a single wheat field. We established a genome-wide map of TE insertion polymorphisms in the population by analyzing recent TE insertions among individuals. We quantified the locus-specific transcription of individual TE copies and found considerable population variation at individual TE loci in the population. About 20% of all TE copies show transcription in the genome suggesting that genomic defenses such as repressive epigenetic marks and repeat-induced polymorphisms are at least partially ineffective at preventing the proliferation of TEs in the genome. A quarter of recent TE insertions are associated with expression variation of neighboring genes providing broad potential to influence trait expression. We indeed found that TE insertions are likely responsible for variation in virulence on the host and potentially diverse components of secondary metabolite production. Our large-scale transcriptomics study emphasizes how TE-derived polymorphisms segregate even in individual microbial populations and can broadly underpin trait variation in pathogens.IMPORTANCEPathogens can rapidly adapt to new hosts, antimicrobials, or changes in the environment. Adaptation arises often from mutations in the genome; however, how such variation is generated remains poorly understood. We investigated the most dynamic regions of the genome of Zymoseptoria tritici, a major fungal pathogen of wheat. We focused on the transcription of transposable elements. A large proportion of the transposable elements not only show signatures of potential activity but are also variable within a single population of the pathogen. We find that this variation in activity is likely influencing many important traits of the pathogen. Hence, our work provides insights into how a microbial species can adapt over the shortest time periods based on the activity of transposable elements.
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Affiliation(s)
- Leen Nanchira Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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2
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Internally Symmetrical Stwintrons and Related Canonical Introns in Hypoxylaceae Species. J Fungi (Basel) 2021; 7:jof7090710. [PMID: 34575748 PMCID: PMC8469720 DOI: 10.3390/jof7090710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 01/01/2023] Open
Abstract
Spliceosomal introns are pervasive in eukaryotes. Intron gains and losses have occurred throughout evolution, but the origin of new introns is unclear. Stwintrons are complex intervening sequences where one of the sequence elements (5′-donor, lariat branch point element or 3′-acceptor) necessary for excision of a U2 intron (external intron) is itself interrupted by a second (internal) U2 intron. In Hypoxylaceae, a family of endophytic fungi, we uncovered scores of donor-disrupted stwintrons with striking sequence similarity among themselves and also with canonical introns. Intron–exon structure comparisons suggest that these stwintrons have proliferated within diverging taxa but also give rise to proliferating canonical introns in some genomes. The proliferated (stw)introns have integrated seamlessly at novel gene positions. The recently proliferated (stw)introns appear to originate from a conserved ancestral stwintron characterised by terminal inverted repeats (45–55 nucleotides), a highly symmetrical structure that may allow the formation of a double-stranded intron RNA molecule. No short tandem duplications flank the putatively inserted intervening sequences, which excludes a DNA transposition-based mechanism of proliferation. It is tempting to suggest that this highly symmetrical structure may have a role in intron proliferation by (an)other mechanism(s).
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3
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Lim CS, Weinstein BN, Roy SW, Brown CM. Analysis of fungal genomes reveals commonalities of intron gain or loss and functions in intron-poor species. Mol Biol Evol 2021; 38:4166-4186. [PMID: 33772558 PMCID: PMC8476143 DOI: 10.1093/molbev/msab094] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Previous evolutionary reconstructions have concluded that early eukaryotic ancestors including both the last common ancestor of eukaryotes and of all fungi had intron-rich genomes. By contrast, some extant eukaryotes have few introns, underscoring the complex histories of intron–exon structures, and raising the question as to why these few introns are retained. Here, we have used recently available fungal genomes to address a variety of questions related to intron evolution. Evolutionary reconstruction of intron presence and absence using 263 diverse fungal species supports the idea that massive intron reduction through intron loss has occurred in multiple clades. The intron densities estimated in various fungal ancestors differ from zero to 7.6 introns per 1 kb of protein-coding sequence. Massive intron loss has occurred not only in microsporidian parasites and saccharomycetous yeasts, but also in diverse smuts and allies. To investigate the roles of the remaining introns in highly-reduced species, we have searched for their special characteristics in eight intron-poor fungi. Notably, the introns of ribosome-associated genes RPL7 and NOG2 have conserved positions; both intron-containing genes encoding snoRNAs. Furthermore, both the proteins and snoRNAs are involved in ribosome biogenesis, suggesting that the expression of the protein-coding genes and noncoding snoRNAs may be functionally coordinated. Indeed, these introns are also conserved in three-quarters of fungi species. Our study shows that fungal introns have a complex evolutionary history and underappreciated roles in gene expression.
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Affiliation(s)
- Chun Shen Lim
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Brooke N Weinstein
- Quantitative & Systems Biology, School of Natural Sciences, University of California-Merced, Merced, CA, USA.,Department of Biology, San Francisco State University, San Francisco, CA, USA
| | - Scott W Roy
- Quantitative & Systems Biology, School of Natural Sciences, University of California-Merced, Merced, CA, USA.,Department of Biology, San Francisco State University, San Francisco, CA, USA
| | - Chris M Brown
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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4
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Mao JM, Wang Y, Yang L, Yao Q, Chen KP. An Intron of Invertebrate Microphthalmia Transcription Factor Gene Is Evolved from a Longer Ancestral Sequence. Evol Bioinform Online 2021; 17:1176934320988558. [PMID: 33551639 PMCID: PMC7841239 DOI: 10.1177/1176934320988558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/29/2020] [Indexed: 11/18/2022] Open
Abstract
Introns are highly variable in number and size. Sequence simulation is an
effective method to elucidate intron evolution patterns. Previously, we have
reported that introns are more likely to evolve through mutation-and-deletion
(MD) rather than through mutation-and-insertion (MI). In the present study, we
further studied evolution models by allowing insertion in the MD model and by
allowing deletion in the MI model at various frequencies. It was found that all
deletion-biased models with proper parameter settings could generate sequences
with attributes matchable to 16 invertebrate introns from the microphthalmia
transcription factor gene, whereas all insertion-biased models with any
parameter settings failed to generate such sequences. We conclude that the
examined invertebrate introns may have evolved from a longer ancestral sequence
in a deletion-biased pattern. The constructed models are useful for studying the
evolution of introns from other genes and/or from other taxonomic groups. (C++
scripts of all deletion- and insertion-biased models are available upon
request.)
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Affiliation(s)
- Jun-Ming Mao
- School of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Yong Wang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
| | - Liu Yang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
| | - Qin Yao
- School of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Ke-Ping Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, China
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Wyka SA, Mondo SJ, Liu M, Dettman J, Nalam V, Broders KD. Whole-Genome Comparisons of Ergot Fungi Reveals the Divergence and Evolution of Species within the Genus Claviceps Are the Result of Varying Mechanisms Driving Genome Evolution and Host Range Expansion. Genome Biol Evol 2021; 13:evaa267. [PMID: 33512490 PMCID: PMC7883665 DOI: 10.1093/gbe/evaa267] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2020] [Indexed: 12/26/2022] Open
Abstract
The genus Claviceps has been known for centuries as an economically important fungal genus for pharmacology and agricultural research. Only recently have researchers begun to unravel the evolutionary history of the genus, with origins in South America and classification of four distinct sections through ecological, morphological, and metabolic features (Claviceps sects. Citrinae, Paspalorum, Pusillae, and Claviceps). The first three sections are additionally characterized by narrow host range, whereas section Claviceps is considered evolutionarily more successful and adaptable as it has the largest host range and biogeographical distribution. However, the reasons for this success and adaptability remain unclear. Our study elucidates factors influencing adaptability by sequencing and annotating 50 Claviceps genomes, representing 21 species, for a comprehensive comparison of genome architecture and plasticity in relation to host range potential. Our results show the trajectory from specialized genomes (sects. Citrinae and Paspalorum) toward adaptive genomes (sects. Pusillae and Claviceps) through colocalization of transposable elements around predicted effectors and a putative loss of repeat-induced point mutation resulting in unconstrained tandem gene duplication coinciding with increased host range potential and speciation. Alterations of genomic architecture and plasticity can substantially influence and shape the evolutionary trajectory of fungal pathogens and their adaptability. Furthermore, our study provides a large increase in available genomic resources to propel future studies of Claviceps in pharmacology and agricultural research, as well as, research into deeper understanding of the evolution of adaptable plant pathogens.
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Affiliation(s)
- Stephen A Wyka
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Stephen J Mondo
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado, USA
- U.S. Department of Energy Joint Genome Institute, Berkeley, California, USA
| | - Miao Liu
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada
| | - Jeremy Dettman
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada
| | - Vamsi Nalam
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Kirk D Broders
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado, USA
- Smithsonian Tropical Research Institute, Panamá, República de Panamá
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6
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Feurtey A, Lorrain C, Croll D, Eschenbrenner C, Freitag M, Habig M, Haueisen J, Möller M, Schotanus K, Stukenbrock EH. Genome compartmentalization predates species divergence in the plant pathogen genus Zymoseptoria. BMC Genomics 2020; 21:588. [PMID: 32842972 PMCID: PMC7448473 DOI: 10.1186/s12864-020-06871-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 06/26/2020] [Indexed: 11/25/2022] Open
Abstract
Background Antagonistic co-evolution can drive rapid adaptation in pathogens and shape genome architecture. Comparative genome analyses of several fungal pathogens revealed highly variable genomes, for many species characterized by specific repeat-rich genome compartments with exceptionally high sequence variability. Dynamic genome structure may enable fast adaptation to host genetics. The wheat pathogen Zymoseptoria tritici with its highly variable genome, has emerged as a model organism to study genome evolution of plant pathogens. Here, we compared genomes of Z. tritici isolates and of sister species infecting wild grasses to address the evolution of genome composition and structure. Results Using long-read technology, we sequenced and assembled genomes of Z. ardabiliae, Z. brevis, Z. pseudotritici and Z. passerinii, together with two isolates of Z. tritici. We report a high extent of genome collinearity among Zymoseptoria species and high conservation of genomic, transcriptomic and epigenomic signatures of compartmentalization. We identify high gene content variability both within and between species. In addition, such variability is mainly limited to the accessory chromosomes and accessory compartments. Despite strong host specificity and non-overlapping host-range between species, predicted effectors are mainly shared among Zymoseptoria species, yet exhibiting a high level of presence-absence polymorphism within Z. tritici. Using in planta transcriptomic data from Z. tritici, we suggest different roles for the shared orthologs and for the accessory genes during infection of their hosts. Conclusion Despite previous reports of high genomic plasticity in Z. tritici, we describe here a high level of conservation in genomic, epigenomic and transcriptomic composition and structure across the genus Zymoseptoria. The compartmentalized genome allows the maintenance of a functional core genome co-occurring with a highly variable accessory genome.
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Affiliation(s)
- Alice Feurtey
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Cécile Lorrain
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany. .,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany. .,INRA Centre Grand Est - Nancy, UMR 1136 INRA/Universite de Lorraine Interactions Arbres/Microorganismes, 54280, Champenoux, France.
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Christoph Eschenbrenner
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Michael Habig
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Janine Haueisen
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Mareike Möller
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany.,Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Klaas Schotanus
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany.,Department of Molecular Genetics and Microbiology, Duke University, Duke University Medical Center, Durham, NC, 27710, USA
| | - Eva H Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
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7
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Bateman A. Division of labour in a matrix, rather than phagocytosis or endosymbiosis, as a route for the origin of eukaryotic cells. Biol Direct 2020; 15:8. [PMID: 32345370 PMCID: PMC7187495 DOI: 10.1186/s13062-020-00260-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 02/25/2020] [Indexed: 12/13/2022] Open
Abstract
Abstract Two apparently irreconcilable models dominate research into the origin of eukaryotes. In one model, amitochondrial proto-eukaryotes emerged autogenously from the last universal common ancestor of all cells. Proto-eukaryotes subsequently acquired mitochondrial progenitors by the phagocytic capture of bacteria. In the second model, two prokaryotes, probably an archaeon and a bacterial cell, engaged in prokaryotic endosymbiosis, with the species resident within the host becoming the mitochondrial progenitor. Both models have limitations. A search was therefore undertaken for alternative routes towards the origin of eukaryotic cells. The question was addressed by considering classes of potential pathways from prokaryotic to eukaryotic cells based on considerations of cellular topology. Among the solutions identified, one, called here the “third-space model”, has not been widely explored. A version is presented in which an extracellular space (the third-space), serves as a proxy cytoplasm for mixed populations of archaea and bacteria to “merge” as a transitionary complex without obligatory endosymbiosis or phagocytosis and to form a precursor cell. Incipient nuclei and mitochondria diverge by division of labour. The third-space model can accommodate the reorganization of prokaryote-like genomes to a more eukaryote-like genome structure. Nuclei with multiple chromosomes and mitosis emerge as a natural feature of the model. The model is compatible with the loss of archaeal lipid biochemistry while retaining archaeal genes and provides a route for the development of membranous organelles such as the Golgi apparatus and endoplasmic reticulum. Advantages, limitations and variations of the “third-space” models are discussed. Reviewers This article was reviewed by Damien Devos, Buzz Baum and Michael Gray.
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Affiliation(s)
- Andrew Bateman
- Division of Experimental Medicine, Department of Medicine, McGill University, Glen Site Pavilion E, 1001 Boulevard Decarie, Montreal, Quebec, H4A 3J1, Canada. .,Centre for Translational Biology, Research Institute of McGill University Health Centre, Glen Site Pavilion E, 1001 Boulevard Decarie, Montreal, Quebec, H4A 3J1, Canada.
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8
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Feurtey A, Stevens DM, Stephan W, Stukenbrock EH. Interspecific Gene Exchange Introduces High Genetic Variability in Crop Pathogen. Genome Biol Evol 2020; 11:3095-3105. [PMID: 31603209 PMCID: PMC6836716 DOI: 10.1093/gbe/evz224] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2019] [Indexed: 12/27/2022] Open
Abstract
Genome analyses have revealed a profound role of hybridization and introgression in the evolution of many eukaryote lineages, including fungi. The impact of recurrent introgression on fungal evolution however remains elusive. Here, we analyzed signatures of introgression along the genome of the fungal wheat pathogen Zymoseptoria tritici. We applied a comparative population genomics approach, including genome data from five Zymoseptoria species, to characterize the distribution and composition of introgressed regions representing segments with an exceptional haplotype pattern. These regions are found throughout the genome, comprising 5% of the total genome and overlapping with > 1,000 predicted genes. We performed window-based phylogenetic analyses along the genome to distinguish regions which have a monophyletic or nonmonophyletic origin with Z. tritici sequences. A majority of nonmonophyletic windows overlap with the highly variable regions suggesting that these originate from introgression. We verified that incongruent gene genealogies do not result from incomplete lineage sorting by comparing the observed and expected length distribution of haplotype blocks resulting from incomplete lineage sorting. Although protein-coding genes are not enriched in these regions, we identify 18 that encode putative virulence determinants. Moreover, we find an enrichment of transposable elements in these regions implying that hybridization may contribute to the horizontal spread of transposable elements. We detected a similar pattern in the closely related species Zymoseptoria ardabiliae, suggesting that hybridization is widespread among these closely related grass pathogens. Overall, our results demonstrate a significant impact of recurrent hybridization on overall genome evolution of this important wheat pathogen.
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Affiliation(s)
- Alice Feurtey
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany.,Botanical Institute, Christian-Albrechts University of Kiel, Germany
| | - Danielle M Stevens
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany.,Botanical Institute, Christian-Albrechts University of Kiel, Germany.,Department of Plant Pathology, University of California, Davis
| | - Wolfgang Stephan
- Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Eva H Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany.,Botanical Institute, Christian-Albrechts University of Kiel, Germany
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9
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The Tc1-like elements with the spliceosomal introns in mollusk genomes. Mol Genet Genomics 2020; 295:621-633. [DOI: 10.1007/s00438-020-01645-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/09/2020] [Indexed: 12/22/2022]
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10
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Targeted and random genetic modification of the black Sigatoka pathogen Pseudocercospora fijiensis by Agrobacterium tumefaciens-mediated transformation. J Microbiol Methods 2018; 148:127-137. [PMID: 29654806 DOI: 10.1016/j.mimet.2018.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
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