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Kuan CS, Ng KP, Yew SM, Umar Meleh H, Seow HF, How KN, Yeo SK, Jee JM, Tan YC, Yee WY, Hoh CC, Velayuthan RD, Na SL, Masri SN, Chew SY, Than LTL. Comparative genomic and phenotypic analyses of pathogenic fungi Neoscytalidium dimidiatum and Bipolaris papendorfii isolated from human skin scraping. Braz J Microbiol 2023; 54:1351-1372. [PMID: 37351789 PMCID: PMC10485236 DOI: 10.1007/s42770-023-01032-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: 11/02/2022] [Accepted: 06/07/2023] [Indexed: 06/24/2023] Open
Abstract
Neoscytalidium dimidiatum and Bipolaris species are fungal plant pathogens that have been reported to cause human diseases. Recently, we have isolated numerous N. dimidiatum and Bipolaris species from the skin scrapings and nails of different patients. In this work, we have sequenced the genome of one strain of N. dimidiatum. The sequenced genome was compared to that of a previously reported Bipolaris papendorfii genome for a better understanding of their complex lifestyle and broad host-range pathogenicity. Both N. dimidiatum UM 880 (~ 43 Mb) and B. papendorfii UM 226 (~ 33 Mb) genomes include 11,015-12,320 putative coding DNA sequences, of which 0.51-2.49% are predicted transposable elements. Analysis of secondary metabolism gene clusters revealed several genes involved in melanin biosynthesis and iron uptake. The arsenal of CAZymes related to plants pathogenicity is comparable between the species, including genes involved in hemicellulose and pectin decomposition. Several important gene encoding keratinolytic peptidases were identified in N. dimidiatum and B. papendorfii, reflecting their potential pathogenic role in causing skin and nail infections. In this study, additional information on the metabolic features of these two species, such as nutritional profiling, pH tolerance, and osmotolerant, are revealed. The genomic characterization of N. dimidiatum and B. papendorfii provides the basis for the future functional studies to gain further insights as to what makes these fungi persist in plants and why they are pathogenic to humans.
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Affiliation(s)
- Chee Sian Kuan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kee Peng Ng
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Su Mei Yew
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Hadiza Umar Meleh
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Heng Fong Seow
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Kang Nien How
- Department of Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Siok Koon Yeo
- School of Biosciences, Taylor's University Lakeside Campus, Subang Jaya, 47500, Selangor, Malaysia
| | - Jap Meng Jee
- School of Biosciences, Taylor's University Lakeside Campus, Subang Jaya, 47500, Selangor, Malaysia
| | - Yung-Chie Tan
- Codon Genomics Sdn Bhd, 43200 Seri Kembangan, Selangor, Malaysia
| | - Wai-Yan Yee
- Codon Genomics Sdn Bhd, 43200 Seri Kembangan, Selangor, Malaysia
| | - Chee-Choong Hoh
- Codon Genomics Sdn Bhd, 43200 Seri Kembangan, Selangor, Malaysia
| | - Rukumani Devi Velayuthan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Shiang Ling Na
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Siti Norbaya Masri
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Shu Yih Chew
- Department of Pathology and Pharmacology, School of Medicine, International Medical University, 57000, Kuala Lumpur, Malaysia
| | - Leslie Thian Lung Than
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
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Abstract
In 1970, the Southern Corn Leaf Blight epidemic ravaged U.S. fields to great economic loss. The outbreak was caused by never-before-seen, supervirulent, Race T of the fungus Cochliobolus heterostrophus. The functional difference between Race T and O, the previously known, far less aggressive strain, is production of T-toxin, a host-selective polyketide. Supervirulence is associated with ~1 Mb of Race T-specific DNA; only a fraction encodes T-toxin biosynthetic genes (Tox1). Tox1 is genetically and physically complex, with unlinked loci (Tox1A, Tox1B) genetically inseparable from breakpoints of a Race O reciprocal translocation that generated hybrid Race T chromosomes. Previously, we identified 10 genes for T-toxin biosynthesis. Unfortunately, high-depth, short-read sequencing placed these genes on four small, unconnected scaffolds surrounded by repeated A+T rich sequence, concealing context. To sort out Tox1 topology and pinpoint the hypothetical Race O translocation breakpoints corresponding to Race T-specific insertions, we undertook PacBio long-read sequencing which revealed Tox1 gene arrangement and the breakpoints. Six Tox1A genes are arranged as three small islands in a Race T-specific sea (~634 kb) of repeats. Four Tox1B genes are linked, on a large loop of Race T-specific DNA (~210 kb). The race O breakpoints are short sequences of race O-specific DNA; corresponding positions in race T are large insertions of race T-specific, A+T rich DNA, often with similarity to transposable (predominantly Gypsy) elements. Nearby, are 'Voyager Starship' elements and DUF proteins. These elements may have facilitated Tox1 integration into progenitor Race O and promoted large scale recombination resulting in race T. IMPORTANCE In 1970 a corn disease epidemic ravaged fields in the United States to great economic loss. The outbreak was caused by a never-before seen, supervirulent strain of the fungal pathogen Cochliobolus heterostrophus. This was a plant disease epidemic, however, the current COVID-19 pandemic of humans is a stark reminder that novel, highly virulent, pathogens evolve with devastating consequences, no matter what the host-animal, plant, or other organism. Long read DNA sequencing technology allowed in depth structural comparisons between the sole, previously known, much less aggressive, version of the pathogen and the supervirulent version and revealed, in meticulous detail, the structure of the unique virulence-causing DNA. These data are foundational for future analysis of mechanisms of DNA acquisition from a foreign source.
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Tang Y, Li X, Hu C, Qiu X, Li J, Li X, Zhu H, Wang J, Sui J, Qiao L. Identification and characterization of transposable element AhMITE1 in the genomes of cultivated and two wild peanuts. BMC Genomics 2022; 23:500. [PMID: 35820800 PMCID: PMC9277781 DOI: 10.1186/s12864-022-08732-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/30/2022] [Indexed: 12/04/2022] Open
Abstract
Background The cultivated peanut (Arachis hypogaea L., AABB) is an allotetraploid hybrid between two diploid peanuts, A. duranensis (AA genome) and A. ipaensis (BB genome). Miniature inverted-repeat transposable elements (MITEs), some of which are known as active nonautonomous DNA transposons with high copy numbers, play important roles in genome evolution and diversification. AhMITE1, a member of the MITE family of transposons, but information on the peanut genomes is still limited. Here, we analyzed AhMITE1, AuMITE1 and ApMITE1 in the cultivated (A. hypogaea) and two wild peanut (A. duranensis and A. ipaensis) genomes. Results The cultivated and the two wild peanut genomes harbored 142, 14 and 21 AhMITE1, AuMITE1 and ApMITE1 family members, respectively. These three family members exhibited highly conserved TIR sequences, and insertions preferentially occurred within 2 kb upstream and downstream of gene-coding and AT-rich regions. Phylogenetic and pairwise nucleotide diversity analysis showed that AhMITE1 and ApMITE1 family members have undergone one round of amplification bursts during the evolution of the peanut genome. PCR analyses were performed in 23 peanut varieties and demonstrated that AhMITE1 is an active transposon and that hybridization or chemical mutagenesis can promote the mobilization of AhMITE1. Conclusions AhMITE1, AuMITE1 and ApMITE1 family members were identified based on local BLAST search with MAK between the cultivated and the two wild peanut genomes. The phylogenetic, nucleotide diversity and variation copy numbers of AhMITE1, AuMITE1 and ApMITE1 members provides opportunities for investigating their roles during peanut evolution. These findings will contribute to knowledge on diversity of AhMITE1, provide information about the potential impact on the gene expression and promote the development of DNA markers in peanut. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08732-0.
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Affiliation(s)
- Yanyan Tang
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China
| | - Xiaoting Li
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China
| | - Changli Hu
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China
| | - Xiaochen Qiu
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China
| | - Jingjing Li
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China
| | - Xin Li
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China
| | - Hong Zhu
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China
| | - Jingshan Wang
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China
| | - Jiongming Sui
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China.
| | - Lixian Qiao
- College of Agronomy, Dry-Land Farming Technology Laboratory of Shandong Province, Key Laboratory of Qingdao Major Crop Germplasm Resource Innovation and Application, Qingdao Agricultural University, Qingdao, 266109, China.
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Singh NK, Badet T, Abraham L, Croll D. Rapid sequence evolution driven by transposable elements at a virulence locus in a fungal wheat pathogen. BMC Genomics 2021; 22:393. [PMID: 34044766 PMCID: PMC8157644 DOI: 10.1186/s12864-021-07691-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 05/07/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Plant pathogens cause substantial crop losses in agriculture production and threaten food security. Plants evolved the ability to recognize virulence factors and pathogens have repeatedly escaped recognition due rapid evolutionary change at pathogen virulence loci (i.e. effector genes). The presence of transposable elements (TEs) in close physical proximity of effector genes can have important consequences for gene regulation and sequence evolution. Species-wide investigations of effector gene loci remain rare hindering our ability to predict pathogen evolvability. RESULTS Here, we performed genome-wide association studies (GWAS) on a highly polymorphic mapping population of 120 isolates of Zymoseptoria tritici, the most damaging pathogen of wheat in Europe. We identified a major locus underlying significant variation in reproductive success of the pathogen and damage caused on the wheat cultivar Claro. The most strongly associated locus is intergenic and flanked by genes encoding a predicted effector and a serine-type endopeptidase. The center of the locus contained a highly dynamic region consisting of multiple families of TEs. Based on a large global collection of assembled genomes, we show that the virulence locus has undergone substantial recent sequence evolution. Large insertion and deletion events generated length variation between the flanking genes by a factor of seven (5-35 kb). The locus showed also strong signatures of genomic defenses against TEs (i.e. RIP) contributing to the rapid diversification of the locus. CONCLUSIONS In conjunction, our work highlights the power of combining GWAS and population-scale genome analyses to investigate major effect loci in pathogens.
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Affiliation(s)
- Nikhil Kumar Singh
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Leen Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland.
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Lelwala RV, Korhonen PK, Young ND, Scott JB, Ades PK, Gasser RB, Taylor PWJ. Comparative genome analysis indicates high evolutionary potential of pathogenicity genes in Colletotrichum tanaceti. PLoS One 2019; 14:e0212248. [PMID: 31150449 PMCID: PMC6544218 DOI: 10.1371/journal.pone.0212248] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 05/02/2019] [Indexed: 01/30/2023] Open
Abstract
Colletotrichum tanaceti is an emerging foliar fungal pathogen of commercially grown pyrethrum (Tanacetum cinerariifolium). Despite being reported consistently from field surveys in Australia, the molecular basis of pathogenicity of C. tanaceti on pyrethrum is unknown. Herein, the genome of C. tanaceti (isolate BRIP57314) was assembled de novo and annotated using transcriptomic evidence. The inferred putative pathogenicity gene suite of C. tanaceti comprised a large array of genes encoding secreted effectors, proteases, CAZymes and secondary metabolites. Comparative analysis of its putative pathogenicity gene profiles with those of closely related species suggested that C. tanaceti likely has additional hosts to pyrethrum. The genome of C. tanaceti had a high repeat content and repetitive elements were located significantly closer to genes inferred to influence pathogenicity than other genes. These repeats are likely to have accelerated mutational and transposition rates in the genome, resulting in a rapid evolution of certain CAZyme families in this species. The C. tanaceti genome showed strong signals of Repeat Induced Point (RIP) mutation which likely caused its bipartite nature consisting of distinct gene-sparse, repeat and A-T rich regions. Pathogenicity genes within these RIP affected regions were likely to have a higher evolutionary rate than the rest of the genome. This "two-speed" genome phenomenon in certain Colletotrichum spp. was hypothesized to have caused the clustering of species based on the pathogenicity genes, to deviate from taxonomic relationships. The large repertoire of pathogenicity factors that potentially evolve rapidly due to the plasticity of the genome, indicated that C. tanaceti has a high evolutionary potential. Therefore, C. tanaceti poses a high-risk to the pyrethrum industry. Knowledge of the evolution and diversity of the putative pathogenicity genes will facilitate future research in disease management of C. tanaceti and other Colletotrichum spp.
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Affiliation(s)
- Ruvini V. Lelwala
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Pasi K. Korhonen
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Neil D. Young
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Jason B. Scott
- Tasmanian Institute of Agriculture, University of Tasmania, Burnie, Tasmania, Australia
| | - Peter K. Ades
- Faculty of Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Robin B. Gasser
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Paul W. J. Taylor
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
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Muszewska A, Steczkiewicz K, Stepniewska-Dziubinska M, Ginalski K. Transposable elements contribute to fungal genes and impact fungal lifestyle. Sci Rep 2019; 9:4307. [PMID: 30867521 PMCID: PMC6416283 DOI: 10.1038/s41598-019-40965-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 02/26/2019] [Indexed: 12/21/2022] Open
Abstract
The last decade brought a still growing experimental evidence of mobilome impact on host's gene expression. We systematically analysed genomic location of transposable elements (TEs) in 625 publicly available fungal genomes from the NCBI database in order to explore their potential roles in genome evolution and correlation with species' lifestyle. We found that non-autonomous TEs and remnant copies are evenly distributed across genomes. In consequence, they also massively overlap with regions annotated as genes, which suggests a great contribution of TE-derived sequences to host's coding genome. Younger and potentially active TEs cluster with one another away from genic regions. This non-randomness is a sign of either selection against insertion of TEs in gene proximity or target site preference among some types of TEs. Proteins encoded by genes with old transposable elements insertions have significantly less repeat and protein-protein interaction motifs but are richer in enzymatic domains. However, genes only proximal to TEs do not display any functional enrichment. Our findings show that adaptive cases of TE insertion remain a marginal phenomenon, and the overwhelming majority of TEs are evolving neutrally. Eventually, animal-related and pathogenic fungi have more TEs inserted into genes than fungi with other lifestyles. This is the first systematic, kingdom-wide study concerning mobile elements and their genomic neighbourhood. The obtained results should inspire further research concerning the roles TEs played in evolution and how they shape the life we know today.
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Affiliation(s)
- Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland.
| | - Kamil Steczkiewicz
- Laboratory of Bioinformatics and Systems Biology, CeNT, University of Warsaw, Zwirki i Wigury 93, 02-089, Warsaw, Poland
| | | | - Krzysztof Ginalski
- Laboratory of Bioinformatics and Systems Biology, CeNT, University of Warsaw, Zwirki i Wigury 93, 02-089, Warsaw, Poland
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Van de Wouw AP, Elliott CE, Popa KM, Idnurm A. Analysis of Repeat Induced Point (RIP) Mutations in Leptosphaeria maculans Indicates Variability in the RIP Process Between Fungal Species. Genetics 2019; 211:89-104. [PMID: 30389803 PMCID: PMC6325690 DOI: 10.1534/genetics.118.301712] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/24/2018] [Indexed: 01/01/2023] Open
Abstract
Gene duplication contributes to evolutionary potential, yet many duplications in a genome arise from the activity of "selfish" genetic elements such as transposable elements. Fungi have a number of mechanisms by which they limit the expansion of transposons, including Repeat Induced Point mutation (RIP). RIP has been best characterized in the Sordariomycete Neurospora crassa, wherein duplicated DNA regions are recognized after cell fusion, but before nuclear fusion during the sexual cycle, and then mutated. While "signatures" of RIP appear in the genome sequences of many fungi, the species most distant from N. crassa in which the process has been experimentally demonstrated to occur is the Dothideomycete Leptosphaeria maculans In the current study, we show that similar to N. crassa, nonlinked duplications can trigger RIP; however, the frequency of the generated RIP mutations is extremely low in L maculans (< 0.1%) and requires a large duplication to initiate RIP, and that multiple premeiotic mitoses are involved in the RIP process. However, a single sexual cycle leads to the generation of progeny with unique haplotypes, despite progeny pairs being generated from mitosis. We hypothesize that these different haplotypes may be the result of the deamination process occurring post karyogamy, leading to unique mutations within each of the progeny pairs. These findings indicate that the RIP process, while common to many fungi, differs between fungi and that this impacts on the fate of duplicated DNA.
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Affiliation(s)
- Angela P Van de Wouw
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Candace E Elliott
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Kerryn M Popa
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Alexander Idnurm
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
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Rao S, Sharda S, Oddi V, Nandineni MR. The Landscape of Repetitive Elements in the Refined Genome of Chilli Anthracnose Fungus Colletotrichum truncatum. Front Microbiol 2018; 9:2367. [PMID: 30337918 PMCID: PMC6180176 DOI: 10.3389/fmicb.2018.02367] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 09/14/2018] [Indexed: 12/15/2022] Open
Abstract
The ascomycete fungus Colletotrichum truncatum is a major phytopathogen with a broad host range which causes anthracnose disease of chilli. The genome sequencing of this fungus led to the discovery of functional categories of genes that may play important roles in fungal pathogenicity. However, the presence of gaps in C. truncatum draft assembly prevented the accurate prediction of repetitive elements, which are the key players to determine the genome architecture and drive evolution and host adaptation. We re-sequenced its genome using single-molecule real-time (SMRT) sequencing technology to obtain a refined assembly with lesser and smaller gaps and ambiguities. This enabled us to study its genome architecture by characterising the repetitive sequences like transposable elements (TEs) and simple sequence repeats (SSRs), which constituted 4.9 and 0.38% of the assembled genome, respectively. The comparative analysis among different Colletotrichum species revealed the extensive repeat rich regions, dominated by Gypsy superfamily of long terminal repeats (LTRs), and the differential composition of SSRs in their genomes. Our study revealed a recent burst of LTR amplification in C. truncatum, C. higginsianum, and C. scovillei. TEs in C. truncatum were significantly associated with secretome, effectors and genes in secondary metabolism clusters. Some of the TE families in C. truncatum showed cytosine to thymine transitions indicative of repeat-induced point mutation (RIP). C. orbiculare and C. graminicola showed strong signatures of RIP across their genomes and "two-speed" genomes with extensive AT-rich and gene-sparse regions. Comparative genomic analyses of Colletotrichum species provided an insight into the species-specific SSR profiles. The SSRs in the coding and non-coding regions of the genome revealed the composition of trinucleotide repeat motifs in exons with potential to alter the translated protein structure through amino acid repeats. This is the first genome-wide study of TEs and SSRs in C. truncatum and their comparative analysis with six other Colletotrichum species, which would serve as a useful resource for future research to get insights into the potential role of TEs in genome expansion and evolution of Colletotrichum fungi and for development of SSR-based molecular markers for population genomic studies.
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Affiliation(s)
- Soumya Rao
- Laboratory of Genomics and Profiling Applications, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Saphy Sharda
- Laboratory of Genomics and Profiling Applications, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Vineesha Oddi
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Madhusudan R. Nandineni
- Laboratory of Genomics and Profiling Applications, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
- Laboratory of DNA Fingerprinting Services, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
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9
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Abstract
Transposable elements have colonized the genomes of nearly all organisms, including fungi. Although transposable elements may sometimes provide beneficial functions to their hosts their overall impact is considered deleterious. As a result, the activity of transposable elements needs to be counterbalanced by the host genome defenses. In fungi, the primary genome defense mechanisms include repeat-induced point mutation (RIP) and methylation induced premeiotically, meiotic silencing by unpaired DNA, sex-induced silencing, cosuppression (also known as somatic quelling), and cotranscriptional RNA surveillance. Recent studies of the filamentous fungus Neurospora crassa have shown that the process of repeat recognition for RIP apparently involves interactions between coaligned double-stranded segments of chromosomal DNA. These studies have also shown that RIP can be mediated by the conserved pathway that establishes transcriptional (heterochromatic) silencing of repetitive DNA. In light of these new findings, RIP emerges as a specialized case of the general phenomenon of heterochromatic silencing of repetitive DNA.
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10
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Analysis of Transposable Elements in Coccidioides Species. J Fungi (Basel) 2018; 4:jof4010013. [PMID: 29371508 PMCID: PMC5872316 DOI: 10.3390/jof4010013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/05/2018] [Accepted: 01/11/2018] [Indexed: 12/24/2022] Open
Abstract
Coccidioides immitis and C. posadasii are primary pathogenic fungi that cause disease in immunologically-normal animals and people. The organism is found exclusively in arid regions of the Southwestern United States, Mexico, and South America, but not in other parts of the world. This study is a detailed analysis of the transposable elements (TE) in Coccidioides spp. As is common in most fungi, Class I and Class II transposons were identified and the LTR Gypsy superfamily is the most common. The minority of Coccidioides Gypsy transposons contained regions highly homologous to polyprotein domains. Phylogenetic analysis of the integrase and reverse transcriptase sequences revealed that many, but not all, of the Gypsy reverse transcriptase and integrase domains clustered by species suggesting extensive transposition after speciation of the two Coccidiodies spp. The TEs were clustered and the distribution is enriched for the ends on contigs. Analysis of gene expression data from C. immitis found that protein-coding genes within 1 kB of hAT or Gypsy TEs were poorly expressed. The expression of C. posadasii genes within 1 kB of Gypsy TEs was also significantly lower compared to all genes but the difference in expression was smaller than C. immitis. C. posadasii orthologs of C. immitis Gyspsy-associated genes were also likely to be TE-associated. In both C. immitis and C. posadasii the TEs were preferentially associated with genes annotated with protein kinase gene ontology terms. These observations suggest that TE may play a role in influencing gene expression in Coccidioides spp. Our hope is that these bioinformatic studies of the potential TE influence on expression and evolution of Coccidioides will prompt the development of testable hypotheses to better understand the role of TEs in the biology and gene regulation of Coccidioides spp.
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11
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Dallery JF, Lapalu N, Zampounis A, Pigné S, Luyten I, Amselem J, Wittenberg AHJ, Zhou S, de Queiroz MV, Robin GP, Auger A, Hainaut M, Henrissat B, Kim KT, Lee YH, Lespinet O, Schwartz DC, Thon MR, O'Connell RJ. Gapless genome assembly of Colletotrichum higginsianum reveals chromosome structure and association of transposable elements with secondary metabolite gene clusters. BMC Genomics 2017; 18:667. [PMID: 28851275 PMCID: PMC5576322 DOI: 10.1186/s12864-017-4083-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/21/2017] [Indexed: 11/11/2022] Open
Abstract
Background The ascomycete fungus Colletotrichum higginsianum causes anthracnose disease of brassica crops and the model plant Arabidopsis thaliana. Previous versions of the genome sequence were highly fragmented, causing errors in the prediction of protein-coding genes and preventing the analysis of repetitive sequences and genome architecture. Results Here, we re-sequenced the genome using single-molecule real-time (SMRT) sequencing technology and, in combination with optical map data, this provided a gapless assembly of all twelve chromosomes except for the ribosomal DNA repeat cluster on chromosome 7. The more accurate gene annotation made possible by this new assembly revealed a large repertoire of secondary metabolism (SM) key genes (89) and putative biosynthetic pathways (77 SM gene clusters). The two mini-chromosomes differed from the ten core chromosomes in being repeat- and AT-rich and gene-poor but were significantly enriched with genes encoding putative secreted effector proteins. Transposable elements (TEs) were found to occupy 7% of the genome by length. Certain TE families showed a statistically significant association with effector genes and SM cluster genes and were transcriptionally active at particular stages of fungal development. All 24 subtelomeres were found to contain one of three highly-conserved repeat elements which, by providing sites for homologous recombination, were probably instrumental in four segmental duplications. Conclusion The gapless genome of C. higginsianum provides access to repeat-rich regions that were previously poorly assembled, notably the mini-chromosomes and subtelomeres, and allowed prediction of the complete SM gene repertoire. It also provides insights into the potential role of TEs in gene and genome evolution and host adaptation in this asexual pathogen. Electronic supplementary material The online version of this article (10.1186/s12864-017-4083-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jean-Félix Dallery
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Nicolas Lapalu
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Antonios Zampounis
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France.,Present Address: Department of Deciduous Fruit Trees, Institute of Plant Breeding and Plant Genetic Resources, Hellenic Agricultural Organization 'Demeter', Naoussa, Greece
| | - Sandrine Pigné
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | | | | | | | - Shiguo Zhou
- Laboratory for Molecular and Computational Genomics, Department of Chemistry, Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Marisa V de Queiroz
- Laboratório de Genética Molecular de Fungos, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Guillaume P Robin
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Annie Auger
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Matthieu Hainaut
- CNRS UMR 7257, Aix-Marseille University, Marseille, France.,INRA, USC 1408 AFMB, Marseille, France
| | - Bernard Henrissat
- CNRS UMR 7257, Aix-Marseille University, Marseille, France.,INRA, USC 1408 AFMB, Marseille, France.,Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ki-Tae Kim
- Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, Seoul National University, Seoul, Korea
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, Seoul National University, Seoul, Korea
| | - Olivier Lespinet
- Laboratoire de Recherche en Informatique, CNRS, Université Paris-Sud, Orsay, France.,Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Orsay, France
| | - David C Schwartz
- Laboratory for Molecular and Computational Genomics, Department of Chemistry, Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michael R Thon
- Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Department of Microbiology and Genetics, University of Salamanca, Salamanca, Spain
| | - Richard J O'Connell
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France.
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12
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Bashyal BM, Rawat K, Sharma S, Kulshreshtha D, Gopala Krishnan S, Singh AK, Dubey H, Solanke AU, Sharma TR, Aggarwal R. Whole Genome Sequencing of Fusarium fujikuroi Provides Insight into the Role of Secretory Proteins and Cell Wall Degrading Enzymes in Causing Bakanae Disease of Rice. FRONTIERS IN PLANT SCIENCE 2017; 8:2013. [PMID: 29230233 PMCID: PMC5711826 DOI: 10.3389/fpls.2017.02013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 11/13/2017] [Indexed: 05/22/2023]
Abstract
Fusarium fujikuroi causing bakanae disease has emerged as one of the major pathogen of rice across the world. The study aims to comparative genomic analysis of Fusarium fujikuroi isolates and identification of the secretary proteins of the fungus involved in rice pathogenesis. In the present study, F. fujikuroi isolate "F250" was sequenced with an assembly size of 42.47 Mb providing coverage of 96.89% on reference IMI58289 genome. A total of 13,603 protein-coding genes were predicted from genome assembly. The average gene density in the F. fujikuroi genome was 315.10 genes per Mb with an average gene length of 1.67 kb. Additionally, 134,374 single nucleotide polymorphisms (SNPs) are identified against IMI58289 isolate, with an average SNP density of 3.11 per kb of genome. Repetitive elements represent approximately 270,550 bp, which is 0.63% of the total genome. In total, 3,109 simple sequence repeats (SSRs), including 302 compound SSRs are identified in the 8,656 scaffolds. Comparative analysis of the isolates of F. fujikuroi revealed that they shared a total of 12,240 common clusters with F250 showing higher similarity with IMI58289. A total of 1,194 secretory proteins were identified in its genome among which there were 356 genes encoding carbohydrate active enzymes (CAZymes) capable for degradation of complex polysaccharides. Out of them glycoside hydrolase (GH) families were most prevalent (41%) followed by carbohydrate esterase (CE). Out of them CE8 (4 genes), PL1 (10 genes), PL3 (5 genes), and GH28 (8 genes) were prominent plant cell wall degrading enzymes families in F250 secretome. Besides this, 585 genes essential for the pathogen-host interactions were also identified. Selected genes were validated through quantitative real-time PCR analyses in resistant and susceptible genotypes of rice at different days of inoculation. The data offers a better understanding of F. fujikuroi genome and will help us enhance our knowledge on Fusarium fujikuroi-rice interactions.
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Affiliation(s)
- Bishnu M. Bashyal
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
- *Correspondence: Bishnu M. Bashyal,
| | - Kirti Rawat
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Sapna Sharma
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Deepika Kulshreshtha
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - S. Gopala Krishnan
- Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Ashok K. Singh
- Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Himanshu Dubey
- ICAR-National Research Centre on Plant Biotechnology, New Delhi, India
| | | | - T. R. Sharma
- ICAR-National Research Centre on Plant Biotechnology, New Delhi, India
| | - Rashmi Aggarwal
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
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13
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Kuan CS, Cham CY, Singh G, Yew SM, Tan YC, Chong PS, Toh YF, Atiya N, Na SL, Lee KW, Hoh CC, Yee WY, Ng KP. Genomic Analyses of Cladophialophora bantiana, a Major Cause of Cerebral Phaeohyphomycosis Provides Insight into Its Lifestyle, Virulence and Adaption in Host. PLoS One 2016; 11:e0161008. [PMID: 27570972 PMCID: PMC5003357 DOI: 10.1371/journal.pone.0161008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/28/2016] [Indexed: 11/18/2022] Open
Abstract
Cladophialophora bantiana is a dematiaceous fungus with a predilection for causing central nervous system (CNS) infection manifesting as brain abscess in both immunocompetent and immunocompromised patients. In this paper, we report comprehensive genomic analyses of C. bantiana isolated from the brain abscess of an immunocompetent man, the first reported case in Malaysia and Southeast Asia. The identity of the fungus was determined using combined morphological analysis and multilocus phylogeny. The draft genome sequence of a neurotrophic fungus, C. bantiana UM 956 was generated using Illumina sequencing technology to dissect its genetic fundamental and basic biology. The assembled 37.1 Mb genome encodes 12,155 putative coding genes, of which, 1.01% are predicted transposable elements. Its genomic features support its saprophytic lifestyle, renowned for its versatility in decomposing hemicellulose and pectin components. The C. bantiana UM 956 was also found to carry some important putative genes that engaged in pathogenicity, iron uptake and homeostasis as well as adaptation to various stresses to enable the organism to survive in hostile microenvironment. This wealth of resource will further catalyse more downstream functional studies to provide better understanding on how this fungus can be a successful and persistent pathogen in human.
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Affiliation(s)
- Chee Sian Kuan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chun Yoong Cham
- Department of Neurosurgery, Hospital Pulau Pinang, Jalan Residensi, Georgetown, Pulau Pinang, Malaysia
- Department of Surgery, Neurosurgical Division, University of Malaya, Kuala Lumpur, Malaysia
| | - Gurmit Singh
- Department of Neurosurgery, Hospital Pulau Pinang, Jalan Residensi, Georgetown, Pulau Pinang, Malaysia
| | - Su Mei Yew
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | | | | | - Yue Fen Toh
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Nadia Atiya
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Shiang Ling Na
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kok Wei Lee
- Codon Genomics SB, Selangor Darul Ehsan, Malaysia
| | | | - Wai-Yan Yee
- Codon Genomics SB, Selangor Darul Ehsan, Malaysia
| | - Kee Peng Ng
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
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14
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Goldfarb M, Santana MF, Salomão TMF, Queiroz MVD, Barros EGD. Evidence of ectopic recombination and a repeat-induced point (RIP) mutation in the genome of Sclerotinia sclerotiorum, the agent responsible for white mold. Genet Mol Biol 2016; 39:426-30. [PMID: 27560652 PMCID: PMC5004834 DOI: 10.1590/1678-4685-gmb-2015-0241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 12/20/2015] [Indexed: 12/24/2022] Open
Abstract
Two retrotransposons from the superfamilies Copia and
Gypsy named as Copia-LTR_SS and
Gypsy-LTR_SS, respectively, were identified in
the genomic bank of Sclerotinia sclerotiorum. These transposable
elements (TEs) contained direct and preserved long terminal repeats (LTR). Domains
related to codified regions for gag protein, integrase, reverse transcriptase and
RNAse H were identified in Copia-LTR_SS, whereas in
Gypsy-LTR_SS only domains for gag, reverse
transcriptase and RNAse H were found. The abundance of identified LTR-Solo suggested
possible genetic recombination events in the S. sclerotiorum genome.
Furthermore, alignment of the sequences for LTR elements from each superfamily
suggested the presence of a RIP (repeat-induced point mutation) silencing mechanism
that may directly affect the evolution of this species.
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Affiliation(s)
- Míriam Goldfarb
- Laboratório de Biologia Molecular de Plantas, Instituto de Biotecnologia Aplicada (BIOAGRO), Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, MG, Brazil
| | - Mateus Ferreira Santana
- Laboratório de Genética Molecular e de Microrganismo, Instituto de Biotecnologia Aplicada (BIOAGRO), Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, MG, Brazil
| | - Tânia Maria Fernandes Salomão
- Laboratório de Biologia Molecular de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, MG, Brazil
| | - Marisa Vieira de Queiroz
- Laboratório de Genética Molecular e de Microrganismo, Instituto de Biotecnologia Aplicada (BIOAGRO), Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, MG, Brazil
| | - Everaldo Gonçalves de Barros
- Laboratório de Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, 70790-160, Brasília, DF, Brazil
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15
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Okagaki LH, Dean RA. The influence of funding sources on the scientific method. MOLECULAR PLANT PATHOLOGY 2016; 17:651-3. [PMID: 26840926 PMCID: PMC5645060 DOI: 10.1111/mpp.12380] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/29/2016] [Indexed: 05/25/2023]
Affiliation(s)
- Laura H Okagaki
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, 27606, NC, USA
| | - Ralph A Dean
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, 27606, NC, USA
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16
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Okagaki LH, Sailsbery JK, Eyre AW, Dean RA. Comparative genome analysis and genome evolution of members of the magnaporthaceae family of fungi. BMC Genomics 2016; 17:135. [PMID: 26911875 PMCID: PMC4766678 DOI: 10.1186/s12864-016-2491-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Magnaporthaceae, a family of ascomycetes, includes three fungi of great economic importance that cause disease in cereal and turf grasses: Magnaporthe oryzae (rice blast), Gaeumannomyces graminis var. tritici (take-all disease), and Magnaporthe poae (summer patch disease). Recently, the sequenced and assembled genomes for these three fungi were reported. Here, the genomes were compared for orthologous genes in order to identified genes that are unique to the Magnaporthaceae family of fungi. In addition, ortholog clustering was used to identify a core proteome for the Magnaporthaceae, which was examined for diversifying and purifying selection and evidence of two-speed genome evolution. RESULTS A genome-scale comparative study was conducted across 74 fungal genomes to identify clusters of orthologous genes unique to the three Magnaporthaceae species as well as species specific genes. We found 1149 clusters that were unique to the Magnaporthaceae family of fungi with 295 of those containing genes from all three species. Gene clusters involved in metabolic and enzymatic activities were highly represented in the Magnaporthaceae specific clusters. Also highly represented in the Magnaporthaceae specific clusters as well as in the species specific genes were transcriptional regulators. In addition, we examined the relationship between gene evolution and distance to repetitive elements found in the genome. No correlations between diversifying or purifying selection and distance to repetitive elements or an increased rate of evolution in secreted and small secreted proteins were observed. CONCLUSIONS Taken together, these data show that at the genome level, there is no evidence to suggest multi-speed genome evolution or that proximity to repetitive elements play a role in diversification of genes.
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Affiliation(s)
- Laura H Okagaki
- Center for Integrated Fungal Research, North Carolina State University, 851 Main campus Drive, Raleigh, NC, 27606, USA. .,Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA.
| | - Joshua K Sailsbery
- Center for Integrated Fungal Research, North Carolina State University, 851 Main campus Drive, Raleigh, NC, 27606, USA. .,Bayer CropScience, Research Triangle Park, 2 TW Alexander Drive, Durham, NC, 27709, USA.
| | - Alexander W Eyre
- Center for Integrated Fungal Research, North Carolina State University, 851 Main campus Drive, Raleigh, NC, 27606, USA. .,Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA.
| | - Ralph A Dean
- Center for Integrated Fungal Research, North Carolina State University, 851 Main campus Drive, Raleigh, NC, 27606, USA. .,Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA.
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17
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A Novel Type Pathway-Specific Regulator and Dynamic Genome Environments of a Solanapyrone Biosynthesis Gene Cluster in the Fungus Ascochyta rabiei. EUKARYOTIC CELL 2015; 14:1102-13. [PMID: 26342019 PMCID: PMC4621316 DOI: 10.1128/ec.00084-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/31/2015] [Indexed: 01/07/2023]
Abstract
Secondary metabolite genes are often clustered together and situated in particular genomic regions, like the subtelomere, that can facilitate niche adaptation in fungi. Solanapyrones are toxic secondary metabolites produced by fungi occupying different ecological niches. Full-genome sequencing of the ascomycete Ascochyta rabiei revealed a solanapyrone biosynthesis gene cluster embedded in an AT-rich region proximal to a telomere end and surrounded by Tc1/Mariner-type transposable elements. The highly AT-rich environment of the solanapyrone cluster is likely the product of repeat-induced point mutations. Several secondary metabolism-related genes were found in the flanking regions of the solanapyrone cluster. Although the solanapyrone cluster appears to be resistant to repeat-induced point mutations, a P450 monooxygenase gene adjacent to the cluster has been degraded by such mutations. Among the six solanapyrone cluster genes (sol1 to sol6), sol4 encodes a novel type of Zn(II)2Cys6 zinc cluster transcription factor. Deletion of sol4 resulted in the complete loss of solanapyrone production but did not compromise growth, sporulation, or virulence. Gene expression studies with the sol4 deletion and sol4-overexpressing mutants delimited the boundaries of the solanapyrone gene cluster and revealed that sol4 is likely a specific regulator of solanapyrone biosynthesis and appears to be necessary and sufficient for induction of the solanapyrone cluster genes. Despite the dynamic surrounding genomic regions, the solanapyrone gene cluster has maintained its integrity, suggesting important roles of solanapyrones in fungal biology.
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18
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Genome Sequences of Three Phytopathogenic Species of the Magnaporthaceae Family of Fungi. G3-GENES GENOMES GENETICS 2015; 5:2539-45. [PMID: 26416668 PMCID: PMC4683626 DOI: 10.1534/g3.115.020057] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Magnaporthaceae is a family of ascomycetes that includes three fungi of great economic importance: Magnaporthe oryzae, Gaeumannomyces graminis var. tritici, and Magnaporthe poae. These three fungi cause widespread disease and loss in cereal and grass crops, including rice blast disease (M. oryzae), take-all disease in wheat and other grasses (G. graminis), and summer patch disease in turf grasses (M. poae). Here, we present the finished genome sequence for M. oryzae and draft sequences for M. poae and G. graminis var. tritici. We used multiple technologies to sequence and annotate the genomes of M. oryzae, M. poae, and G. graminis var. tritici. The M. oryzae genome is now finished to seven chromosomes whereas M. poae and G. graminis var. tritici are sequenced to 40.0× and 25.0× coverage respectively. Gene models were developed by the use of multiple computational techniques and further supported by RNAseq data. In addition, we performed preliminary analysis of genome architecture and repetitive element DNA.
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19
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Lu S, Gillian Turgeon B, Edwards MC. A ToxA-like protein from Cochliobolus heterostrophus induces light-dependent leaf necrosis and acts as a virulence factor with host selectivity on maize. Fungal Genet Biol 2015; 81:12-24. [PMID: 26051492 DOI: 10.1016/j.fgb.2015.05.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 11/30/2022]
Abstract
ToxA, the first discovered fungal proteinaceous host-selective toxin (HST), was originally identified in 1989 from the tan spot fungus Pyrenophora tritici-repentis (Ptr). About 25years later, a homolog was identified in the leaf/glume blotch fungus Stagonospora nodorum (Parastagonospora nodorum), also a pathogen of wheat. Here we report the identification and function of a ToxA-like protein from the maize pathogen Cochliobolus heterostrophus (Ch) that possesses necrosis-inducing activity specifically against maize. ChToxA is encoded by a 535-bp open reading frame featuring a ToxA-specific intron with unusual splicing sites (5'-ATAAGT…TAC-3') at conserved positions relative to PtrToxA. The protein shows 64% similarity to PtrToxA and is predicted to adopt a similar three-dimensional structure, although lacking the arginyl-glycyl-aspartic acid (RGD) motif reported to be required for internalization into sensitive wheat mesophyll cells. Reverse-transcriptase PCR revealed that the ChTOXA gene expression is up-regulated in planta, relative to axenic culture. Plant assays indicated that the recombinant ChToxA protein induces light-dependent leaf necrosis in a host-selective manner on maize inbred lines. Gene deletion experiments confirmed that ChtoxA mutants are reduced in virulence on specific ChToxA-sensitive maize lines, relative to virulence caused by wild-type strains. Database searches identified potential ChToxA homologues in other plant-pathogenic ascomycetes. Sequence and phylogenetic analyses revealed that the corresponding ToxA-like proteins include one member recently shown to be associated with formation of penetration hypha. These results provide the first evidence that C. heterostrophus is capable of producing proteinaceous HSTs as virulence factors in addition to well-known secondary metabolite-type toxins produced biosynthetically by polyketide synthase megaenzymes. Further studies on ChToxA may provide new insights into effector evolution in host-pathogen interactions.
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Affiliation(s)
- Shunwen Lu
- US Department of Agriculture, Agricultural Research Service, Cereal Crops Research Unit, Fargo, ND 58102-2765, USA.
| | - B Gillian Turgeon
- Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Michael C Edwards
- US Department of Agriculture, Agricultural Research Service, Cereal Crops Research Unit, Fargo, ND 58102-2765, USA
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20
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Kuan CS, Yew SM, Toh YF, Chan CL, Ngeow YF, Lee KW, Na SL, Yee WY, Hoh CC, Ng KP. Dissecting the fungal biology of Bipolaris papendorfii: from phylogenetic to comparative genomic analysis. DNA Res 2015; 22:219-32. [PMID: 25922537 PMCID: PMC4463846 DOI: 10.1093/dnares/dsv007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 03/28/2015] [Indexed: 01/21/2023] Open
Abstract
Bipolaris papendorfii has been reported as a fungal plant pathogen that rarely causes opportunistic infection in humans. Secondary metabolites isolated from this fungus possess medicinal and anticancer properties. However, its genetic fundamental and basic biology are largely unknown. In this study, we report the first draft genome sequence of B. papendorfii UM 226 isolated from the skin scraping of a patient. The assembled 33.4 Mb genome encodes 11,015 putative coding DNA sequences, of which, 2.49% are predicted transposable elements. Multilocus phylogenetic and phylogenomic analyses showed B. papendorfii UM 226 clustering with Curvularia species, apart from other plant pathogenic Bipolaris species. Its genomic features suggest that it is a heterothallic fungus with a putative unique gene encoding the LysM-containing protein which might be involved in fungal virulence on host plants, as well as a wide array of enzymes involved in carbohydrate metabolism, degradation of polysaccharides and lignin in the plant cell wall, secondary metabolite biosynthesis (including dimethylallyl tryptophan synthase, non-ribosomal peptide synthetase, polyketide synthase), the terpenoid pathway and the caffeine metabolism. This first genomic characterization of B. papendorfii provides the basis for further studies on its biology, pathogenicity and medicinal potential.
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Affiliation(s)
- Chee Sian Kuan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Su Mei Yew
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Yue Fen Toh
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Chai Ling Chan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Yun Fong Ngeow
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Kok Wei Lee
- Codon Genomics SB, Jalan Bandar Lapan Belas, Selangor Darul Ehsan 47160, Malaysia
| | - Shiang Ling Na
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Wai-Yan Yee
- Codon Genomics SB, Jalan Bandar Lapan Belas, Selangor Darul Ehsan 47160, Malaysia
| | - Chee-Choong Hoh
- Codon Genomics SB, Jalan Bandar Lapan Belas, Selangor Darul Ehsan 47160, Malaysia
| | - Kee Peng Ng
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
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21
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Santana MF, Silva JCF, Mizubuti ESG, Araújo EF, Queiroz MV. Analysis of Tc1-Mariner elements in Sclerotinia sclerotiorum suggests recent activity and flexible transposases. BMC Microbiol 2014; 14:256. [PMID: 25281292 PMCID: PMC4188875 DOI: 10.1186/s12866-014-0256-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/25/2014] [Indexed: 12/12/2022] Open
Abstract
Background Sclerotinia sclerotiorum is a necrotrophic fungus that is pathogenic to many plants. Genomic analysis of its revealed transposable element expansion that has strongly influenced the evolutionary trajectory of several species. Transposons from the Tc1-Mariner superfamily are thought to be ubiquitous components of fungal genomes and are generally found in low copy numbers with large numbers of deleterious mutations in their transposase coding sequence. Results This study shows that the genome of S. sclerotiorum has a large number of copies of Tc1-Mariner transposons, and in silico analysis shows evidence that they were recently active. This finding was confirmed by expressed sequence tag (EST) analysis. Fourteen new Tc1-Mariner transposon families that were distributed throughout the genome were identified, and in some cases, due to the excision/retention of introns, different transcripts were observed for the same family, which might be the result of an efficient strategy to circumvent mutations that generate premature stop codons in the RNA sequence. In addition, the presence of these introns shows that the transposase protein has a flexible coding sequence and, consequently, conformation. No evidence for RIP-like gene silencing mechanisms, which are commonly found in fungi, was found in the identified Tc1-Mariner elements, and analysis of the genomic insertion sites of these elements showed that they were widely distributed throughout the genome with some copies located near the 3′ regions of genes. In particular, EST analysis demonstrated that one of these copies was co-expressed with a gene, which showed the potential for these elements to undergo exaptation. Conclusions Fourteen novel Tc1-Mariner families were characterized. Some families had evidence of introns, which might or might not be excised depending on the family or element in question, and this finding demonstrates a possible strategy for overcoming possible mutations that generate premature stop codons in a RNA sequence. Tc1-Mariner elements likely play an important role in the structure and evolution of the S. sclerotiorum genome.
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