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Gervais NC, Shapiro RS. Discovering the hidden function in fungal genomes. Nat Commun 2024; 15:8219. [PMID: 39300175 DOI: 10.1038/s41467-024-52568-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 09/11/2024] [Indexed: 09/22/2024] Open
Abstract
New molecular technologies have helped unveil previously unexplored facets of the genome beyond the canonical proteome, including microproteins and short ORFs, products of alternative splicing, regulatory non-coding RNAs, as well as transposable elements, cis-regulatory DNA, and other highly repetitive regions of DNA. In this Review, we highlight what is known about this 'hidden genome' within the fungal kingdom. Using well-established model systems as a contextual framework, we describe key elements of this hidden genome in diverse fungal species, and explore how these factors perform critical functions in regulating fungal metabolism, stress tolerance, and pathogenesis. Finally, we discuss new technologies that may be adapted to further characterize the hidden genome in fungi.
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Affiliation(s)
- Nicholas C Gervais
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
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Urquhart A, Vogan AA, Gluck-Thaler E. Starships: a new frontier for fungal biology. Trends Genet 2024:S0168-9525(24)00183-5. [PMID: 39299886 DOI: 10.1016/j.tig.2024.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Revised: 08/20/2024] [Accepted: 08/20/2024] [Indexed: 09/22/2024]
Abstract
Transposable elements (TEs) are semiautonomous genetic entities that proliferate in genomes. We recently discovered the Starships, a previously hidden superfamily of giant TEs found in a diverse subphylum of filamentous fungi, the Pezizomycotina. Starships are unlike other eukaryotic TEs because they have evolved mechanisms for both mobilizing entire genes, including those encoding conditionally beneficial phenotypes, and for horizontally transferring between individuals. We argue that Starships have unrivaled capacity to engage their fungal hosts as genetic parasites and mutualists, revealing unexplored terrain for investigating the ecoevolutionary dynamics of TE-eukaryote interactions. We build on existing models of fungal genome evolution by conceptualizing Starships as a distinct genomic compartment whose dynamics profoundly shape fungal biology.
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Affiliation(s)
- Andrew Urquhart
- Systematic Biology, Department of Organismal Biology, Uppsala University, Uppsala, 752 36, Sweden
| | - Aaron A Vogan
- Systematic Biology, Department of Organismal Biology, Uppsala University, Uppsala, 752 36, Sweden
| | - Emile Gluck-Thaler
- Department of Plant Pathology, University of Wisconsin - Madison, Madison, WI 53706, USA; Wisconsin Institute for Discovery, Madison, WI 53706, USA.
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See PT, Iagallo EM, Marathamuthu KA, Wood B, Aboukhaddour R, Moffat CS. A New ToxA Haplotype in the Wheat Fungal Pathogen Bipolaris sorokiniana. PHYTOPATHOLOGY 2024; 114:1525-1532. [PMID: 38530294 DOI: 10.1094/phyto-10-23-0370-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
The necrotrophic effector ToxA is a well-studied virulence factor produced by several fungal necrotrophs. Initially cloned from the wheat tan spot pathogen Pyrenophora tritici-repentis in 1996, ToxA was found almost a decade later in another fungal pathogen, Parastagonospora nodorum, and its sister species, Parastagonospora pseudonodorum. In 2018, ToxA was detected in a third wheat fungal pathogenic species, Bipolaris sorokiniana, which causes spot blotch disease. However, unlike the case with P. tritici-repentis and P. nodorum, the ToxA in B. sorokiniana has only been investigated in recent years. In this report, five Australian B. sorokiniana isolates were assessed for the presence of ToxA. Four isolates were found to contain ToxA. While one isolate harbored the previously reported ToxA haplotype sequence (ToxA19), three isolates contain a different haplotype, designated herein as ToxA25, which has a nonsynonymous mutation resulting in an amino acid change of glycine to arginine at position 168. Both B. sorokiniana ToxA isoforms, when heterologously expressed in Escherichia coli, exhibited the classic ToxA necrosis-inducing activity on ToxA-sensitive Tsn1 cultivars. Preliminary analysis of the B. sorokiniana isolates in Australian wheat cultivars showed that isolates with ToxA19, ToxA25, or ToxA-deficient displayed various degrees of virulence, with the most aggressive isolates observed for those producing ToxA. Differences in spot blotch disease severity between Tsn1 and tsn1 cultivars were observed; however, this was not limited to the ToxA-producing isolates. The overall results suggest that the virulence of the Australian B. sorokiniana isolates is diverse, with the significance of ToxA-Tsn1 interactions depending on individual isolates.
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Affiliation(s)
- Pao Theen See
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Elyce M Iagallo
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Kalai A Marathamuthu
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Blake Wood
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Reem Aboukhaddour
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Center, Lethbridge, Alberta, Canada
| | - Caroline S Moffat
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
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Gluck-Thaler E, Forsythe A, Puerner C, Stajich JE, Croll D, Cramer RA, Vogan AA. Giant transposons promote strain heterogeneity in a major fungal pathogen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.601215. [PMID: 38979181 PMCID: PMC11230402 DOI: 10.1101/2024.06.28.601215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Fungal infections are difficult to prevent and treat in large part due to heterogeneity in clinically relevant phenotypes. However, the genetic mechanisms driving pathogen variation remain poorly understood. Here, we determined the extent to which Starships -giant transposons capable of mobilizing numerous fungal genes-generate genetic and phenotypic variability in the human pathogen Aspergillus fumigatus . We analyzed 519 diverse strains, including 12 newly sequenced with long-read technology, to reveal 20 distinct Starships that generate genomic heterogeneity over timescales impacting experimental reproducibility. Starship -mobilized genes encode diverse functions, including biofilm-related virulence factors and biosynthetic gene clusters, and many are differentially expressed during infection and antifungal exposure in a strain-specific manner. These findings support a new model of fungal pathogenesis wherein Starships mediate variation in virulence-related gene content and expression. Together, our results demonstrate that Starships are a foundational mechanism generating disease-relevant genotypic and, in turn, phenotypic heterogeneity in a major human fungal pathogen.
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Gluck-Thaler E, Vogan A. Systematic identification of cargo-mobilizing genetic elements reveals new dimensions of eukaryotic diversity. Nucleic Acids Res 2024; 52:5496-5513. [PMID: 38686785 PMCID: PMC11162782 DOI: 10.1093/nar/gkae327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 03/12/2024] [Accepted: 04/15/2024] [Indexed: 05/02/2024] Open
Abstract
Cargo-mobilizing mobile elements (CMEs) are genetic entities that faithfully transpose diverse protein coding sequences. Although common in bacteria, we know little about eukaryotic CMEs because no appropriate tools exist for their annotation. For example, Starships are giant fungal CMEs whose functions are largely unknown because they require time-intensive manual curation. To address this knowledge gap, we developed starfish, a computational workflow for high-throughput eukaryotic CME annotation. We applied starfish to 2 899 genomes of 1 649 fungal species and found that starfish recovers known Starships with 95% combined precision and recall while expanding the number of annotated elements ten-fold. Extant Starship diversity is partitioned into 11 families that differ in their enrichment patterns across fungal classes. Starship cargo changes rapidly such that elements from the same family differ substantially in their functional repertoires, which are predicted to contribute to diverse biological processes such as metabolism. Many elements have convergently evolved to insert into 5S rDNA and AT-rich sequence while others integrate into random locations, revealing both specialist and generalist strategies for persistence. Our work establishes a framework for advancing mobile element biology and provides the means to investigate an emerging dimension of eukaryotic genetic diversity, that of genomes within genomes.
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Affiliation(s)
- Emile Gluck-Thaler
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Neuchâtel 2000, Switzerland
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Wisconsin Institute for Discovery, Madison, WI 53706, USA
| | - Aaron A Vogan
- Systematic Biology, Department of Organismal Biology, Uppsala University, Uppsala, 752 36, Sweden
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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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Hafez M, Gourlie R, McDonald M, Telfer M, Carmona MA, Sautua FJ, Moffat CS, Moolhuijzen PM, See PT, Aboukhaddour R. Evolution of the Toxb Gene in Pyrenophora tritici-repentis and Related Species. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:327-337. [PMID: 37759383 DOI: 10.1094/mpmi-08-23-0114-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Pyrenophora tritici-repentis (tan spot) is a destructive foliar pathogen of wheat with global impact. This ascomycete fungus possesses a highly plastic open pangenome shaped by the gain and loss of effector genes. This study investigated the allelic variations in the chlorosis-encoding gene ToxB across 422 isolates representing all identified pathotypes and worldwide origins. To gain better insights into ToxB evolution, we examined its presence and variability in other Pyrenophora spp. A ToxB haplotype network was constructed, revealing the evolutionary relationships of this gene (20 haplotypes) across four Pyrenophora species. Notably, toxb, the homolog of ToxB, was detected for the first time in the barley pathogen Pyrenophora teres. The ToxB/toxb genes display evidence of selection that is characterized by loss of function, duplication, and diverse mutations. Within the ToxB/toxb open reading frame, 72 mutations were identified, including 14 synonymous, 55 nonsynonymous, and 3 indel mutations. Remarkably, a, ∼5.6-kb Copia-like retrotransposon, named Copia-1_Ptr, was found inserted in the toxb gene of a race 3 isolate. This insert disrupted the ToxB gene's function, a first case of effector gene disruption by a transposable element in P. tritici-repentis. Additionally, a microsatellite with 25 nucleotide repeats (0 to 10) in the upstream region of ToxB suggested a potential mechanism influencing ToxB expression and regulation. Exploring ToxB-like protein distribution in other ascomycetes revealed the presence of ToxB-like proteins in 19 additional species, including the Leotiomycetes class for the first time. The presence/absence pattern of ToxB-like proteins defied species relatedness compared with a phylogenetic tree, suggesting a past horizontal gene transfer event during the evolution of the ToxB gene. [Formula: see text] Copyright © 2024 His Majesty the King in Right of Canada, as represented by the Minister of Agriculture and Agri-Food. This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Mohamed Hafez
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, Canada
- Botany and Microbiology Department, Faculty of Science, Suez University, Suez, Egypt
| | - Ryan Gourlie
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, Canada
| | - Megan McDonald
- School of Biosciences, University of Birmingham, Institute of Microbiology and Infection, Edgbaston, Birmingham, U.K
| | - Melissa Telfer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, Canada
| | - Marcelo A Carmona
- Cátedra de Fitopatología, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Francisco J Sautua
- Cátedra de Fitopatología, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Caroline S Moffat
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Australia
| | - Paula M Moolhuijzen
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Australia
| | - Pao Theen See
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Australia
| | - Reem Aboukhaddour
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, Canada
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Aditya S, Aggarwal R, Bashyal BM, Gurjar MS, Saharan MS, Aggarwal S. Unraveling the dynamics of wheat leaf blight complex: isolation, characterization, and insights into pathogen population under Indian conditions. Front Microbiol 2024; 15:1287721. [PMID: 38450160 PMCID: PMC10915091 DOI: 10.3389/fmicb.2024.1287721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Accepted: 01/31/2024] [Indexed: 03/08/2024] Open
Abstract
Wheat, a staple food crop for 35% of the global population, faces a threat from Helminthosporium leaf blight (HLB), a complex of spot blotch (Bipolaris sorokiniana) and tan spot (Pyrenophora-tritici-repentis) diseases under warm and humid conditions. However, in Indian conditions, the knowledge of existing pathogen populations associated with the HLB complex is limited and largely dominated by only B. sorokiniana (spot blotch). To address this, diseased samples were collected from all six wheat growing zones during 2020-2022. The pathogenic species were identified through in-depth morphological characterization, supplemented with ITS-rDNA and GAPDH sequence analysis, a diagnostic SCAR marker, and pathogenicity studies on two wheat varieties: Sonalika and HD2733. The 32 isolates collected from 10 different states consist of B. spicifera (12.5% of all isolates), Exserohilum rostratum (9.3%), Bipolaris oryzae (3.1%), and B. sorokiniana (75%). B. sorokiniana exhibited the highest disease severity on both varieties. Other lesser-known pathogenic species also produced comparable disease severity as B. sorokiniana isolates and, therefore are economically important. Unraveling pathogen composition and biology aids in disease control and resistance breeding. Our study highlights economically impactful and lesser-known pathogenic species causing wheat leaf blight/spot blotch in India, guiding both current management and future resistance breeding strategies in plant pathology.
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Affiliation(s)
- Sanghmitra Aditya
- Fungal Molecular Biology Laboratory, Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Rashmi Aggarwal
- Fungal Molecular Biology Laboratory, Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
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Angst P, Dexter E, Stillman JH. Genome assemblies of two species of porcelain crab, Petrolisthes cinctipes and Petrolisthes manimaculis (Anomura: Porcellanidae). G3 (BETHESDA, MD.) 2024; 14:jkad281. [PMID: 38079165 PMCID: PMC10849366 DOI: 10.1093/g3journal/jkad281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 11/09/2023] [Indexed: 02/09/2024]
Abstract
Crabs are a large subtaxon of the Arthropoda, the most diverse and species-rich metazoan group. Several outstanding questions remain regarding crab diversification, including about the genomic capacitors of physiological and morphological adaptation, that cannot be answered with available genomic resources. Physiologically and ecologically diverse Anomuran porcelain crabs offer a valuable model for investigating these questions and hence genomic resources of these crabs would be particularly useful. Here, we present the first two genome assemblies of congeneric and sympatric Anomuran porcelain crabs, Petrolisthes cinctipes and Petrolisthes manimaculis from different microhabitats. Pacific Biosciences high-fidelity sequencing led to genome assemblies of 1.5 and 0.9 Gb, with N50s of 706.7 and 218.9 Kb, respectively. Their assembly length difference can largely be attributed to the different levels of interspersed repeats in their assemblies: The larger genome of P. cinctipes has more repeats (1.12 Gb) than the smaller genome of P. manimaculis (0.54 Gb). For obtaining high-quality annotations of 44,543 and 40,315 protein-coding genes in P. cinctipes and P. manimaculis, respectively, we used RNA-seq as part of a larger annotation pipeline. Contrarily to the large-scale differences in repeat content, divergence levels between the two species as estimated from orthologous protein-coding genes are moderate. These two high-quality genome assemblies allow future studies to examine the role of environmental regulation of gene expression in the two focal species to better understand physiological response to climate change, and provide the foundation for studies in fine-scale genome evolution and diversification of crabs.
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Affiliation(s)
- Pascal Angst
- Department of Environmental Sciences, Zoology, University of Basel, 4051 Basel, Switzerland
| | - Eric Dexter
- Department of Environmental Sciences, Zoology, University of Basel, 4051 Basel, Switzerland
| | - Jonathon H Stillman
- Department of Environmental Sciences, Zoology, University of Basel, 4051 Basel, Switzerland
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA
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Zaccaron AZ, Stergiopoulos I. Analysis of five near-complete genome assemblies of the tomato pathogen Cladosporium fulvum uncovers additional accessory chromosomes and structural variations induced by transposable elements effecting the loss of avirulence genes. BMC Biol 2024; 22:25. [PMID: 38281938 PMCID: PMC10823647 DOI: 10.1186/s12915-024-01818-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/04/2024] [Indexed: 01/30/2024] Open
Abstract
BACKGROUND Fungal plant pathogens have dynamic genomes that allow them to rapidly adapt to adverse conditions and overcome host resistance. One way by which this dynamic genome plasticity is expressed is through effector gene loss, which enables plant pathogens to overcome recognition by cognate resistance genes in the host. However, the exact nature of these loses remains elusive in many fungi. This includes the tomato pathogen Cladosporium fulvum, which is the first fungal plant pathogen from which avirulence (Avr) genes were ever cloned and in which loss of Avr genes is often reported as a means of overcoming recognition by cognate tomato Cf resistance genes. A recent near-complete reference genome assembly of C. fulvum isolate Race 5 revealed a compartmentalized genome architecture and the presence of an accessory chromosome, thereby creating a basis for studying genome plasticity in fungal plant pathogens and its impact on avirulence genes. RESULTS Here, we obtained near-complete genome assemblies of four additional C. fulvum isolates. The genome assemblies had similar sizes (66.96 to 67.78 Mb), number of predicted genes (14,895 to 14,981), and estimated completeness (98.8 to 98.9%). Comparative analysis that included the genome of isolate Race 5 revealed high levels of synteny and colinearity, which extended to the density and distribution of repetitive elements and of repeat-induced point (RIP) mutations across homologous chromosomes. Nonetheless, structural variations, likely mediated by transposable elements and effecting the deletion of the avirulence genes Avr4E, Avr5, and Avr9, were also identified. The isolates further shared a core set of 13 chromosomes, but two accessory chromosomes were identified as well. Accessory chromosomes were significantly smaller in size, and one carried pseudogenized copies of two effector genes. Whole-genome alignments further revealed genomic islands of near-zero nucleotide diversity interspersed with islands of high nucleotide diversity that co-localized with repeat-rich regions. These regions were likely generated by RIP, which generally asymmetrically affected the genome of C. fulvum. CONCLUSIONS Our results reveal new evolutionary aspects of the C. fulvum genome and provide new insights on the importance of genomic structural variations in overcoming host resistance in fungal plant pathogens.
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Affiliation(s)
- Alex Z Zaccaron
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616-8751, USA
| | - Ioannis Stergiopoulos
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616-8751, USA.
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Dehbi I, Achemrk O, Ezzouggari R, El Jarroudi M, Mokrini F, Legrifi I, Belabess Z, Laasli SE, Mazouz H, Lahlali R. Beneficial Microorganisms as Bioprotectants against Foliar Diseases of Cereals: A Review. PLANTS (BASEL, SWITZERLAND) 2023; 12:4162. [PMID: 38140489 PMCID: PMC10747484 DOI: 10.3390/plants12244162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023]
Abstract
Cereal production plays a major role in both animal and human diets throughout the world. However, cereal crops are vulnerable to attacks by fungal pathogens on the foliage, disrupting their biological cycle and photosynthesis, which can reduce yields by 15-20% or even 60%. Consumers are concerned about the excessive use of synthetic pesticides given their harmful effects on human health and the environment. As a result, the search for alternative solutions to protect crops has attracted the interest of scientists around the world. Among these solutions, biological control using beneficial microorganisms has taken on considerable importance, and several biological control agents (BCAs) have been studied, including species belonging to the genera Bacillus, Pseudomonas, Streptomyces, Trichoderma, Cladosporium, and Epicoccum, most of which include plants of growth-promoting rhizobacteria (PGPRs). Bacillus has proved to be a broad-spectrum agent against these leaf cereal diseases. Interaction between plant and beneficial agents occurs as direct mycoparasitism or hyperparasitism by a mixed pathway via the secretion of lytic enzymes, growth enzymes, and antibiotics, or by an indirect interaction involving competition for nutrients or space and the induction of host resistance (systemic acquired resistance (SAR) or induced systemic resistance (ISR) pathway). We mainly demonstrate the role of BCAs in the defense against fungal diseases of cereal leaves. To enhance a solution-based crop protection approach, it is also important to understand the mechanism of action of BCAs/molecules/plants. Research in the field of preventing cereal diseases is still ongoing.
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Affiliation(s)
- Ilham Dehbi
- Phytopathology Unit, Department of Plant Protection, Ecole National of Agriculture Meknes, Km10, Rte Haj Kaddour, BP S/40, Meknes 50001, Morocco; (I.D.); (O.A.); (R.E.); (I.L.); (S.-E.L.)
- Laboratory of Plant Biotechnology and Molecular Biology, Faculty of Sciences, Moulay Ismail University, BP 11201, Zitoune, Meknes 50000, Morocco;
| | - Oussama Achemrk
- Phytopathology Unit, Department of Plant Protection, Ecole National of Agriculture Meknes, Km10, Rte Haj Kaddour, BP S/40, Meknes 50001, Morocco; (I.D.); (O.A.); (R.E.); (I.L.); (S.-E.L.)
| | - Rachid Ezzouggari
- Phytopathology Unit, Department of Plant Protection, Ecole National of Agriculture Meknes, Km10, Rte Haj Kaddour, BP S/40, Meknes 50001, Morocco; (I.D.); (O.A.); (R.E.); (I.L.); (S.-E.L.)
- Laboratory of Biotechnology, Conservation, and Valorization of Natural Resources (LBCVNR), Faculty of Sciences Dhar El Mehraz, Sidi Mohamed Ben Abdallah University, Fez 30000, Morocco
| | - Moussa El Jarroudi
- Department of Environmental Sciences and Management, SPHERES Research Unit, University of Liège, 6700 Arlon, Belgium;
| | - Fouad Mokrini
- Biotechnology Unit, Regional Center of Agricultural Research, INRA–Morocco, Rabat 10080, Morocco;
| | - Ikram Legrifi
- Phytopathology Unit, Department of Plant Protection, Ecole National of Agriculture Meknes, Km10, Rte Haj Kaddour, BP S/40, Meknes 50001, Morocco; (I.D.); (O.A.); (R.E.); (I.L.); (S.-E.L.)
| | - Zineb Belabess
- Plant Protection Laboratory, Regional Center of Agricultural Research of Meknes, National Institute of Agricultural Research, Km 13, Route Haj Kaddour, BP 578, Meknes 50001, Morocco;
| | - Salah-Eddine Laasli
- Phytopathology Unit, Department of Plant Protection, Ecole National of Agriculture Meknes, Km10, Rte Haj Kaddour, BP S/40, Meknes 50001, Morocco; (I.D.); (O.A.); (R.E.); (I.L.); (S.-E.L.)
| | - Hamid Mazouz
- Laboratory of Plant Biotechnology and Molecular Biology, Faculty of Sciences, Moulay Ismail University, BP 11201, Zitoune, Meknes 50000, Morocco;
| | - Rachid Lahlali
- Phytopathology Unit, Department of Plant Protection, Ecole National of Agriculture Meknes, Km10, Rte Haj Kaddour, BP S/40, Meknes 50001, Morocco; (I.D.); (O.A.); (R.E.); (I.L.); (S.-E.L.)
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12
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Nakamoto AA, Joubert PM, Krasileva KV. Intraspecific Variation of Transposable Elements Reveals Differences in the Evolutionary History of Fungal Phytopathogen Pathotypes. Genome Biol Evol 2023; 15:evad206. [PMID: 37975814 PMCID: PMC10691877 DOI: 10.1093/gbe/evad206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 11/01/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023] Open
Abstract
Transposable elements (TEs) contribute to intraspecific variation and play important roles in the evolution of fungal genomes. However, our understanding of the processes that shape TE landscapes is limited, as is our understanding of the relationship between TE content, population structure, and evolutionary history of fungal species. Fungal plant pathogens, which often have host-specific populations, are useful systems in which to study intraspecific TE content diversity. Here, we describe TE dynamics in five lineages of Magnaporthe oryzae, the fungus that causes blast disease of rice, wheat, and many other grasses. We identified differences in TE content across these lineages and showed that recent lineage-specific expansions of certain TEs have contributed to overall greater TE content in rice-infecting and Setaria-infecting lineages. We reconstructed the evolutionary histories of long terminal repeat-retrotransposon expansions and found that in some cases they were caused by complex proliferation dynamics of one element and in others by multiple elements from an older population of TEs multiplying in parallel. Additionally, we found evidence suggesting the recent transfer of a DNA transposon between rice- and wheat-infecting M. oryzae lineages and a region showing evidence of homologous recombination between those lineages, which could have facilitated such a transfer. By investigating intraspecific TE content variation, we uncovered key differences in the proliferation dynamics of TEs in various pathotypes of a fungal plant pathogen, giving us a better understanding of the evolutionary history of the pathogen itself.
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Affiliation(s)
- Anne A Nakamoto
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Pierre M Joubert
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Ksenia V Krasileva
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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Welgemoed T, Duong TA, Barnes I, Stukenbrock EH, Berger DK. Population genomic analyses suggest recent dispersal events of the pathogen Cercospora zeina into East and Southern African maize cropping systems. G3 (BETHESDA, MD.) 2023; 13:jkad214. [PMID: 37738420 PMCID: PMC10627275 DOI: 10.1093/g3journal/jkad214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/03/2023] [Accepted: 09/06/2023] [Indexed: 09/24/2023]
Abstract
A serious factor hampering global maize production is gray leaf spot disease. Cercospora zeina is one of the causative pathogens, but population genomics analysis of C. zeina is lacking. We conducted whole-genome Illumina sequencing of a representative set of 30 C. zeina isolates from Kenya and Uganda (East Africa) and Zambia, Zimbabwe, and South Africa (Southern Africa). Selection of the diverse set was based on microsatellite data from a larger collection of the pathogen. Pangenome analysis of the C. zeina isolates was done by (1) de novo assembly of the reads with SPAdes, (2) annotation with BRAKER, and (3) protein clustering with OrthoFinder. A published long-read assembly of C. zeina (CMW25467) from Zambia was included and annotated using the same pipeline. This analysis revealed 790 non-shared accessory and 10,677 shared core orthogroups (genes) between the 31 isolates. Accessory gene content was largely shared between isolates from all countries, with a few genes unique to populations from Southern Africa (32) or East Africa (6). There was a significantly higher proportion of effector genes in the accessory secretome (44%) compared to the core secretome (24%). PCA, ADMIXTURE, and phylogenetic analysis using a neighbor-net network indicated a population structure with a geographical subdivision between the East African isolates and the Southern African isolates, although gene flow was also evident. The small pangenome and partial population differentiation indicated recent dispersal of C. zeina into Africa, possibly from 2 regional founder populations, followed by recurrent gene flow owing to widespread maize production across sub-Saharan Africa.
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Affiliation(s)
- Tanya Welgemoed
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Tuan A Duong
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Irene Barnes
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Eva H Stukenbrock
- Environmental Genomics, Christian-Albrechts University of Kiel, Am Botanischen Garten 1-11, Kiel 24118, Germany
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, Plön 24306, Germany
| | - Dave K Berger
- Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
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Aboukhaddour R, Hafez M, McDonald M, Moffat CS, Navathe S, Friesen TL, Strelkov SE, Oliver RP, Tan KC, Liu Z, Moolhuijzen PM, Phan H, See PT, Solomon PS. A Revised Nomenclature for ToxA Haplotypes Across Multiple Fungal Species. PHYTOPATHOLOGY 2023; 113:1180-1184. [PMID: 36809076 DOI: 10.1094/phyto-01-23-0017-sc] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
ToxA is one of the most studied proteinaceous necrotrophic effectors produced by plant pathogens. It has been identified in four pathogens (Pyrenophora tritici-repentis, Parastagonospora nodorum, Parastagonospora pseudonodorum [formerly Parastagonospora avenaria f. sp. tritici], and Bipolaris sorokiniana) causing leaf spot diseases on cereals worldwide. To date, 24 different ToxA haplotypes have been identified. Some P. tritici-repentis and related species also express ToxB, another small protein necrotrophic effector. We present here a revised and standardized nomenclature for these effectors, which could be extended to other poly-haplotypic genes found across multiple species.
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Affiliation(s)
- Reem Aboukhaddour
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Center, Lethbridge, Alberta, Canada
| | - Mohamed Hafez
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Center, Lethbridge, Alberta, Canada
| | - Megan McDonald
- School of Biosciences, University of Birmingham, Institute of Microbiology and Infection, Edgbaston, Birmingham, U.K
| | - Caroline S Moffat
- Centre for Crop Disease and Management, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Sudhir Navathe
- Agharkar Research Institute, Department Science and Technology, Govt. of India, Pune, 411004, India
| | - Timothy L Friesen
- USDA-ARS, Edward T. Schafer Agricultural Research Center, Cereal Crops Research Unit, Fargo, ND 58102-2765, U.S.A
- Department of Plant Pathology, North Dakota State University, Fargo, ND, U.S.A
| | - Stephen E Strelkov
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | | | - Kar-Chun Tan
- Centre for Crop Disease and Management, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND, U.S.A
| | - Paula M Moolhuijzen
- Centre for Crop Disease and Management, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Huyen Phan
- Centre for Crop Disease and Management, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Pao Theen See
- Centre for Crop Disease and Management, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Peter S Solomon
- Division of Plant Sciences, Research School of Biology, The Australian National University ACT, Australia
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Urquhart AS, Vogan AA, Gardiner DM, Idnurm A. Starships are active eukaryotic transposable elements mobilized by a new family of tyrosine recombinases. Proc Natl Acad Sci U S A 2023; 120:e2214521120. [PMID: 37023132 PMCID: PMC10104507 DOI: 10.1073/pnas.2214521120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 01/04/2023] [Indexed: 04/07/2023] Open
Abstract
Transposable elements in eukaryotic organisms have historically been considered "selfish," at best conferring indirect benefits to their host organisms. The Starships are a recently discovered feature in fungal genomes that are, in some cases, predicted to confer beneficial traits to their hosts and also have hallmarks of being transposable elements. Here, we provide experimental evidence that Starships are indeed autonomous transposons, using the model Paecilomyces variotii, and identify the HhpA "Captain" tyrosine recombinase as essential for their mobilization into genomic sites with a specific target site consensus sequence. Furthermore, we identify multiple recent horizontal gene transfers of Starships, implying that they jump between species. Fungal genomes have mechanisms to defend against mobile elements, which are frequently detrimental to the host. We discover that Starships are also vulnerable to repeat-induced point mutation defense, thereby having implications on the evolutionary stability of such elements.
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Affiliation(s)
- Andrew S. Urquhart
- Commonwealth Scientific and Industrial Research Organisation, St Lucia, QLD4067, Australia
- Applied Biosciences, Macquarie University, Macquarie Park, NSW2109, Australia
| | - Aaron A. Vogan
- Department of Organismal Biology, Uppsala University, 752 36Uppsala, Sweden
| | - Donald M. Gardiner
- Commonwealth Scientific and Industrial Research Organisation, St Lucia, QLD4067, Australia
- University of Queensland, St Lucia, QLD4067, Australia
| | - Alexander Idnurm
- School of BioSciences, University of Melbourne, Parkville, VIC3010, Australia
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16
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Wacker T, Helmstetter N, Wilson D, Fisher MC, Studholme DJ, Farrer RA. Two-speed genome evolution drives pathogenicity in fungal pathogens of animals. Proc Natl Acad Sci U S A 2023; 120:e2212633120. [PMID: 36595674 PMCID: PMC9926174 DOI: 10.1073/pnas.2212633120] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/14/2022] [Indexed: 01/05/2023] Open
Abstract
The origins and evolution of virulence in amphibian-infecting chytrids Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) are largely unknown. Here, we use deep nanopore sequencing of Bsal and comparative genomics against 21 high-quality genome assemblies that span the fungal Chytridiomycota. We discover that Bsal has the most repeat-rich genome of the Chytridiomycota, comprising 40.9% repetitive elements; this genome has expanded to more than 3× the length of its conspecific Bd, with autonomous and fully functional LTR/Gypsy elements contributing significantly to the expansion. The M36 metalloprotease virulence factors are highly expanded (n = 177) in Bsal, most of which (53%) are flanked by transposable elements, suggesting they have a repeat-associated expansion. We find enrichment upstream of M36 metalloprotease genes of three novel repeat families belonging to the repeat superfamily of LINEs that are implicated with gene copy number variations. Additionally, Bsal has a highly compartmentalized genome architecture, with virulence factors enriched in gene-sparse/repeat-rich compartments, while core conserved genes are enriched in gene-rich/repeat-poor compartments. Genes upregulated during infection are primarily found in the gene-sparse/repeat-rich compartment in both Bd and Bsal. Furthermore, genes with signatures of positive selection in Bd are enriched in repeat-rich regions, suggesting these regions are a cradle for the evolution of chytrid pathogenicity. These are the hallmarks of two-speed genome evolution, and this study provides evidence of two-speed genomes in an animal pathogen, shedding light on the evolution of fungal pathogens of vertebrates driving global declines and extinctions.
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Affiliation(s)
- Theresa Wacker
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Nicolas Helmstetter
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Matthew C. Fisher
- Medical Research Council (MRC) Centre for Global Infectious Disease Analysis, Imperial College London, LondonW12 0BZ, United Kingdom
| | - David J. Studholme
- Department of Biosciences, University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Rhys A. Farrer
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
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