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Fouché G, Rosati D, Venet C, Josserand H, Latorse MP, Debieu D, Fillinger S. LC-MS/MS-Based Fungicide Accumulation Assay to Demonstrate Efflux Activity in the Wheat Pathogen Zymoseptoria tritici. Microorganisms 2022; 10:microorganisms10081494. [PMID: 35893552 PMCID: PMC9331226 DOI: 10.3390/microorganisms10081494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/24/2022] [Accepted: 07/12/2022] [Indexed: 11/16/2022] Open
Abstract
Increased drug efflux compromises the efficacy of a large panel of treatments in the clinic against cancer or bacterial, fungal, and viral diseases, and in agriculture due to the emergence of multidrug-resistant pathogenic fungi. Until recently, to demonstrate increased drug efflux, the use of labeled drugs or fluorescent dyes was necessary. With the increasing sensitivity of detection devices, direct assessment of drug efflux has become realistic. Here, we describe a medium-throughput method to assess the intracellular drug concentration in the plant pathogenic fungus Zymoseptoria tritici cultivated in the presence of a sublethal fungicide concentration. As a model fungicide, we used the succinate-dehydrogenase inhibitor boscalid. The boscalid concentration was assessed in the different culture fractions using mass spectrometry linked to liquid chromatography (LC-MS/MS). The ratio between the intracellular and total boscalid amount was used as an inversed proxy for the efflux activity. Using isogenic mutant strains known for their differential efflux capacities, we validated the negative correlation between the intracellular boscalid concentration and efflux activity. In addition, intra-cellular fungicide accumulation explains the susceptibility of the tested strains to boscalid. This assay may be useful in lead development when a new molecule displays good inhibitory activity against its isolated target protein but fails to control the target organism.
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Affiliation(s)
- Guillaume Fouché
- UR BIOGER, INRAE, Université Paris-Saclay, 78850 Thiverval-Grignon, France; (G.F.); (D.D.)
| | - Dominique Rosati
- La Dargoire Research Center, Bayer SAS, 69009 Lyon, France; (D.R.); (C.V.); (H.J.); (M.-P.L.)
| | - Catherine Venet
- La Dargoire Research Center, Bayer SAS, 69009 Lyon, France; (D.R.); (C.V.); (H.J.); (M.-P.L.)
| | - Hervé Josserand
- La Dargoire Research Center, Bayer SAS, 69009 Lyon, France; (D.R.); (C.V.); (H.J.); (M.-P.L.)
| | - Marie-Pascale Latorse
- La Dargoire Research Center, Bayer SAS, 69009 Lyon, France; (D.R.); (C.V.); (H.J.); (M.-P.L.)
| | - Danièle Debieu
- UR BIOGER, INRAE, Université Paris-Saclay, 78850 Thiverval-Grignon, France; (G.F.); (D.D.)
| | - Sabine Fillinger
- UR BIOGER, INRAE, Université Paris-Saclay, 78850 Thiverval-Grignon, France; (G.F.); (D.D.)
- Correspondence:
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52
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McDonald BA, Suffert F, Bernasconi A, Mikaberidze A. How large and diverse are field populations of fungal plant pathogens? The case of
Zymoseptoria tritici. Evol Appl 2022; 15:1360-1373. [PMID: 36187182 PMCID: PMC9488677 DOI: 10.1111/eva.13434] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/28/2022] [Accepted: 06/06/2022] [Indexed: 12/02/2022] Open
Abstract
Pathogen populations differ in the amount of genetic diversity they contain. Populations carrying higher genetic diversity are thought to have a greater evolutionary potential than populations carrying less diversity. We used published studies to estimate the range of values associated with two critical components of genetic diversity, the number of unique pathogen genotypes and the number of spores produced during an epidemic, for the septoria tritici blotch pathogen Zymoseptoria tritici. We found that wheat fields experiencing typical levels of infection are likely to carry between 3.1 and 14.0 million pathogen genotypes per hectare and produce at least 2.1–9.9 trillion pycnidiospores per hectare. Given the experimentally derived mutation rate of 3 × 10−10 substitutions per site per cell division, we estimate that between 27 and 126 million pathogen spores carrying adaptive mutations to counteract fungicides and resistant cultivars will be produced per hectare during a growing season. This suggests that most of the adaptive mutations that have been observed in Z. tritici populations can emerge through local selection from standing genetic variation that already exists within each field. The consequences of these findings for disease management strategies are discussed.
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Affiliation(s)
- Bruce A. McDonald
- Plant Pathology Group Institute of Integrative Biology ETH Zurich Zurich Switzerland
| | - Frederic Suffert
- Université Paris‐Saclay INRAE, UR BIOGER Thiverval‐Grignon France
| | - Alessio Bernasconi
- Plant Pathology Group Institute of Integrative Biology ETH Zurich Zurich Switzerland
| | - Alexey Mikaberidze
- School of Agriculture Policy and Development, University of Reading Whiteknights Reading UK
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Tiley AMM, Lawless C, Pilo P, Karki SJ, Lu J, Long Z, Gibriel H, Bailey AM, Feechan A. The Zymoseptoria tritici white collar-1 gene, ZtWco-1, is required for development and virulence on wheat. Fungal Genet Biol 2022; 161:103715. [PMID: 35709910 DOI: 10.1016/j.fgb.2022.103715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 06/02/2022] [Accepted: 06/06/2022] [Indexed: 11/04/2022]
Abstract
The fungus Zymoseptoria tritici causes Septoria Tritici Blotch (STB), which is one of the most devastating diseases of wheat in Europe. There are currently no fully durable methods of control against Z. tritici, so novel strategies are urgently required. One of the ways in which fungi are able to respond to their surrounding environment is through the use of photoreceptor proteins which detect light signals. Although previous evidence suggests that Z. tritici can detect light, no photoreceptor genes have been characterised in this pathogen. This study characterises ZtWco-1, a predicted photoreceptor gene in Z. tritici. The ZtWco-1 gene is a putative homolog to the blue light photoreceptor from Neurospora crassa, wc-1. Z. tritici mutants with deletions in ZtWco-1 have defects in hyphal branching, melanisation and virulence on wheat. In addition, we identify the putative circadian clock gene ZtFrq in Z. tritici. This study provides evidence for the genetic regulation of light detection in Z. tritici and it open avenues for future research into whether this pathogen has a circadian clock.
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Affiliation(s)
- Anna M M Tiley
- Agri-Food Biosciences Institute, 18a Newforge Ln, Belfast BT9 5PX, United Kingdom; School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland.
| | - Colleen Lawless
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland; School of Biology and Environmental Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Paola Pilo
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Sujit J Karki
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Jijun Lu
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Zhuowei Long
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Hesham Gibriel
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland; Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Andy M Bailey
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
| | - Angela Feechan
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland.
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54
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Zaccaron AZ, Chen LH, Samaras A, Stergiopoulos I. A chromosome-scale genome assembly of the tomato pathogen Cladosporium fulvum reveals a compartmentalized genome architecture and the presence of a dispensable chromosome. Microb Genom 2022; 8:000819. [PMID: 35471194 PMCID: PMC9453070 DOI: 10.1099/mgen.0.000819] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 03/29/2022] [Indexed: 01/25/2023] Open
Abstract
Cladosporium fulvum is a fungal pathogen that causes leaf mould of tomato. The reference genome of this pathogen was released in 2012 but its high repetitive DNA content prevented a contiguous assembly and further prohibited the analysis of its genome architecture. In this study, we combined third generation sequencing technology with the Hi-C chromatin conformation capture technique, to produce a high-quality and near complete genome assembly and gene annotation of a Race 5 isolate of C. fulvum. The resulting genome assembly contained 67.17 Mb organized into 14 chromosomes (Chr1-to-Chr14), all of which were assembled telomere-to-telomere. The smallest of the chromosomes, Chr14, is only 460 kb in size and contains 25 genes that all encode hypothetical proteins. Notably, PCR assays revealed that Chr14 was absent in 19 out of 24 isolates of a world-wide collection of C. fulvum, indicating that Chr14 is dispensable. Thus, C. fulvum is currently the second species of Capnodiales shown to harbour dispensable chromosomes. The genome of C. fulvum Race 5 is 49.7 % repetitive and contains 14 690 predicted genes with an estimated completeness of 98.9%, currently one of the highest among the Capnodiales. Genome structure analysis revealed a compartmentalized architecture composed of gene-dense and repeat-poor regions interspersed with gene-sparse and repeat-rich regions. Nearly 39.2 % of the C. fulvum Race 5 genome is affected by Repeat-Induced Point (RIP) mutations and evidence of RIP leakage toward non-repetitive regions was observed in all chromosomes, indicating the RIP plays an important role in the evolution of this pathogen. Finally, 345 genes encoding candidate effectors were identified in C. fulvum Race 5, with a significant enrichment of their location in gene-sparse regions, in accordance with the 'two-speed genome' model of evolution. Overall, the new reference genome of C. fulvum presents several notable features and is a valuable resource for studies in plant pathogens.
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Affiliation(s)
- Alex Z. Zaccaron
- Department of Plant Pathology, University of California Davis, Davis, USA
| | - Li-Hung Chen
- Department of Plant Pathology, University of California Davis, Davis, USA
- Present address: Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Anastasios Samaras
- Department of Plant Pathology, University of California Davis, Davis, USA
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Wang W, Wang H, Cheng X, Wu M, Song Y, Liu X, Loni PC, Tuovinen OH. Different responses of bacteria and fungi to environmental variables and corresponding community assembly in Sb-contaminated soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 298:118812. [PMID: 35031403 DOI: 10.1016/j.envpol.2022.118812] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/20/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Bacterial communities in antimony (Sb) polluted soils have been well addressed, whereas the important players fungal communities are far less studied to date. Here, we report different responses of bacterial and fungal communities to Sb contamination and the ecological processes controlling their community assembly. Soil samples in the Xikuangshan mining area were collected and subjected to high through-put sequencing of 16S rRNA and ITS1 to investigate bacterial and fungal communities, respectively, along an Sb gradient. Sb speciation in the soil samples and other physicochemical parameters were analyzed as well. Bacterial communities were dominated by Deltaproteobacteria in the soil with highest Sb concentration, whereas Chloroflexi were dominant in the soil with lowest Sb concentration. Fungal communities in high-Sb soils were predominated by unclassified Fungi, whilst Leotiomycetes were dominant in low-Sb soil samples. Multivariate analysis indicated that Sb, pH and soil texture were the main drivers to strongly impact microbial communities. We further identified Sb-resistant microbial groups via correlation analysis. In total, 18 bacterial amplicon sequence variants (ASVs) were found to potentially involve in biogeochemical cycles such as Sb oxidation, sulfur oxidation or nitrate reduction, whereas 12 fungal ASVs were singled out for potential heavy metal resistance and plant growth promotion. Community assembly analysis revealed that variable selection contributed 100% to bacterial community assembly under acidic or high Sb concentration conditions, whereas homogeneous selection dominated fungal community assembly with a contribution over 78.9%. The community assembly of Sb-resistant microorganisms was mainly controlled by stochastic process. The results offer new insights into microbial ecology in Sb-contaminated soils, especially on the different responses of microbial communities under identical environmental stress and the different ecological processes underlining bacterial and fungal community assembly.
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Affiliation(s)
- Weiqi Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
| | - Hongmei Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China.
| | - Xiaoyu Cheng
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
| | - Mengxiaojun Wu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
| | - Yuyang Song
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
| | - Xiaoyan Liu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
| | - Prakash C Loni
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
| | - Olli H Tuovinen
- Department of Microbiology, Ohio State University, Columbus, OH, 43210, USA
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56
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van de Vossenberg BTLH, Prodhomme C, Vossen JH, van der Lee TAJ. Synchytrium endobioticum, the potato wart disease pathogen. MOLECULAR PLANT PATHOLOGY 2022; 23:461-474. [PMID: 35029012 PMCID: PMC8916214 DOI: 10.1111/mpp.13183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
UNLABELLED Potato wart disease is considered one of the most important quarantine pests for cultivated potato and is caused by the obligate biotrophic chytrid fungus Synchytrium endobioticum. This review integrates observations from early potato wart research and recent molecular, genetic, and genomic studies of the pathogen and its host potato. Taxonomy, epidemiology, pathology, and formation of new pathotypes are discussed, and a model for molecular S. endobioticum-potato interaction is proposed. TAXONOMY Currently classified as kingdom: Fungi, phylum: Chytridiomycota, class: Chytridiomycetes, order: Chytridiales, family: Synchytriaceae, genus: Synchytrium, species: Synchytrium endobioticum, there is strong molecular support for Synchytriaceae to be transferred to the order Synchytriales. HOSTS AND DISEASE SYMPTOMS Solanum tuberosum is the main host for S. endobioticum but other solanaceous species have been reported as alternative hosts. It is not known if these alternative hosts play a role in the survival of the pathogen in (borders of) infested fields. Disease symptoms on potato tubers are characterized by the warty cauliflower-like malformations that are the result of cell enlargement and cell multiplication induced by the pathogen. Meristematic tissue on tubers, stolons, eyes, sprouts, and inflorescences can be infected while the potato root system seems to be immune. PATHOTYPES For S. endobioticum over 40 pathotypes, which are defined as groups of isolates with a similar response to a set of differential potato varieties, are described. Pathotypes 1(D1), 2(G1), 6(O1), and 18(T1) are currently regarded to be most widespread. However, with the current differential set other pathogen diversity largely remains undetected. PATHOGEN-HOST INTERACTION A single effector has been described for S. endobioticum (AvrSen1), which is recognized by the potato Sen1 resistance gene product. This is also the first effector that has been described in Chytridiomycota, showing that in this fungal division resistance also fits the gene-for-gene concept. Although significant progress was made in the last decade in mapping wart disease resistance loci, not all resistances present in potato breeding germplasm could be identified. The use of resistant varieties plays an essential role in disease management.
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Affiliation(s)
| | | | - Jack H. Vossen
- Plant BreedingWageningen University & ResearchWageningenNetherlands
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57
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Phenotyping Mediterranean Durum Wheat Landraces for Resistance to Zymoseptoria tritici in Tunisia. Genes (Basel) 2022; 13:genes13020355. [PMID: 35205399 PMCID: PMC8872163 DOI: 10.3390/genes13020355] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/21/2022] [Accepted: 02/09/2022] [Indexed: 02/01/2023] Open
Abstract
Durum wheat landraces have huge potential for the identification of genetic factors valuable for improving resistance to biotic stresses. Tunisia is known as a hot spot for Septoria tritici blotch disease (STB), caused by the fungus Zymoseptoria tritici (Z. tritici). In this context, a collection of 3166 Mediterranean durum wheat landraces were evaluated at the seedling and adult stages for STB resistance in the 2016–2017 cropping season under field conditions in Kodia (Tunisia). Unadapted/susceptible accessions were eliminated to reach the final set of 1059 accessions; this was termed the Med-collection, which comprised accessions from 13 countries and was also screened in the 2018–2019 cropping season. The Med-collection showed high frequency of resistance reactions, among which over 50% showed an immune reaction (HR) at both seedling and adult growth stages. Interestingly, 92% of HR and R accessions maintained their resistance levels across the two years, confirming the highly significant correlation found between seedling- and adult-stage reactions. Plant Height was found to have a negative significant effect on adult-stage resistance, suggesting that either this trait can influence disease severity, or that it can be due to environmental/epidemiological factors. Accessions from Italy showed the highest variability, while those from Portugal, Spain and Tunisia showed the highest levels of resistance at both growth stages, suggesting that the latter accessions may harbor novel QTLs effective for STB resistance.
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58
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Crane CF, Nemacheck JA, Subramanyam S, Williams CE, Goodwin SB. SLAG: A Program for Seeded Local Assembly of Genes in Complex Genomes. Mol Ecol Resour 2022; 22:1999-2017. [PMID: 34995394 PMCID: PMC9303413 DOI: 10.1111/1755-0998.13580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/11/2021] [Accepted: 12/20/2021] [Indexed: 12/04/2022]
Abstract
Although finished genomes have become more common, there is still a need for assemblies of individual genes or chromosomal regions when only unassembled reads are available. slag (Seeded Local Assembly of Genes) fulfils this need by performing iterative local assembly based on cycles of matching‐read retrieval with blast and assembly with cap3, phrap, spades, canu or unicycler. The target sequence can be nucleotide or protein. Read fragmentation allows slag to use phrap or cap3 to assemble long reads at lower coverage (e.g., 5×) than is possible with canu or unicycler. In simple, nonrepetitive genomes, a slag assembly can cover a whole chromosome, but in complex genomes the growth of target‐matching contigs is limited as additional reads are consumed by consensus contigs consisting of repetitive elements. Apart from genomic complexity, contig length and correctness depend on read length and accuracy. With pyrosequencing or Illumina reads, slag‐assembled contigs are accurate enough to allow design of PCR primers, while contigs assembled from Oxford Nanopore or pre‐HiFi Pacific Biosciences long reads are generally only accurate enough to design baiting sequences for further targeted sequencing. In an application with real reads, slag successfully extended sequences for four wheat genes, which were verified by cloning and Sanger sequencing of overlapping amplicons. slag is a robust alternative to atram2 for local assemblies, especially for read sets with less than 20× coverage. slag is freely available at https://github.com/cfcrane/SLAG.
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Affiliation(s)
- Charles F Crane
- USDA-Agricultural Research Service, Crop Production & Pest Control Research Unit, Purdue University campus, 915 West State Street, West Lafayette, Indiana, 47907-2054, USA.,Department of Botany & Plant Pathology, Purdue University, 915 W. State Street, West Lafayette, IN, 47907-2054, USA
| | - Jill A Nemacheck
- USDA-Agricultural Research Service, Crop Production & Pest Control Research Unit, Purdue University campus, 915 West State Street, West Lafayette, Indiana, 47907-2054, USA.,Department of Entomology, Purdue University, 901 W. State Street, West Lafayette, IN, 47907, USA
| | - Subhashree Subramanyam
- USDA-Agricultural Research Service, Crop Production & Pest Control Research Unit, Purdue University campus, 915 West State Street, West Lafayette, Indiana, 47907-2054, USA.,Department of Entomology, Purdue University, 901 W. State Street, West Lafayette, IN, 47907, USA
| | - Christie E Williams
- USDA-Agricultural Research Service, Crop Production & Pest Control Research Unit, Purdue University campus, 915 West State Street, West Lafayette, Indiana, 47907-2054, USA
| | - Stephen B Goodwin
- USDA-Agricultural Research Service, Crop Production & Pest Control Research Unit, Purdue University campus, 915 West State Street, West Lafayette, Indiana, 47907-2054, USA.,Department of Botany & Plant Pathology, Purdue University, 915 W. State Street, West Lafayette, IN, 47907-2054, USA
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Battache M, Lebrun MH, Sakai K, Soudière O, Cambon F, Langin T, Saintenac C. Blocked at the Stomatal Gate, a Key Step of Wheat Stb16q-Mediated Resistance to Zymoseptoria tritici. FRONTIERS IN PLANT SCIENCE 2022; 13:921074. [PMID: 35832231 PMCID: PMC9271956 DOI: 10.3389/fpls.2022.921074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/03/2022] [Indexed: 05/11/2023]
Abstract
Septoria tritici blotch (STB), caused by the fungus Zymoseptoria tritici, is among the most threatening wheat diseases in Europe. Genetic resistance remains one of the main environmentally sustainable strategies to efficiently control STB. However, the molecular and physiological mechanisms underlying resistance are still unknown, limiting the implementation of knowledge-driven management strategies. Among the 22 known major resistance genes (Stb), the recently cloned Stb16q gene encodes a cysteine-rich receptor-like kinase conferring a full broad-spectrum resistance against Z. tritici. Here, we showed that an avirulent Z. tritici inoculated on Stb16q quasi near isogenic lines (NILs) either by infiltration into leaf tissues or by brush inoculation of wounded tissues partially bypasses Stb16q-mediated resistance. To understand this bypass, we monitored the infection of GFP-labeled avirulent and virulent isolates on Stb16q NILs, from germination to pycnidia formation. This quantitative cytological analysis revealed that 95% of the penetration attempts were unsuccessful in the Stb16q incompatible interaction, while almost all succeeded in compatible interactions. Infectious hyphae resulting from the few successful penetration events in the Stb16q incompatible interaction were arrested in the sub-stomatal cavity of the primary-infected stomata. These results indicate that Stb16q-mediated resistance mainly blocks the avirulent isolate during its stomatal penetration into wheat tissue. Analyses of stomatal aperture of the Stb16q NILs during infection revealed that Stb16q triggers a temporary stomatal closure in response to an avirulent isolate. Finally, we showed that infiltrating avirulent isolates into leaves of the Stb6 and Stb9 NILs also partially bypasses resistances, suggesting that arrest during stomatal penetration might be a common major mechanism for Stb-mediated resistances.
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Affiliation(s)
- Mélissa Battache
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Marc-Henri Lebrun
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Kaori Sakai
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Olivier Soudière
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Florence Cambon
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Thierry Langin
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Cyrille Saintenac
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
- *Correspondence: Cyrille Saintenac,
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60
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Nagel JH, Wingfield MJ, Slippers B. Next-generation sequencing provides important insights into the biology and evolution of the Botryosphaeriaceae. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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61
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Kowalczyk JE, Saha S, Mäkelä MR. Application of CRISPR/Cas9 Tools for Genome Editing in the White-Rot Fungus Dichomitus squalens. Biomolecules 2021; 11:1526. [PMID: 34680159 PMCID: PMC8533725 DOI: 10.3390/biom11101526] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/04/2021] [Accepted: 10/12/2021] [Indexed: 12/26/2022] Open
Abstract
Dichomitus squalens is an emerging reference species that can be used to investigate white-rot fungal plant biomass degradation, as it has flexible physiology to utilize different types of biomass as sources of carbon and energy. Recent comparative (post-) genomic studies on D. squalens resulted in an increasingly detailed knowledge of the genes and enzymes involved in the lignocellulose breakdown in this fungus and showed a complex transcriptional response in the presence of lignocellulose-derived compounds. To fully utilize this increasing amount of data, efficient and reliable genetic manipulation tools are needed, e.g., to characterize the function of certain proteins in vivo and facilitate the construction of strains with enhanced lignocellulolytic capabilities. However, precise genome alterations are often very difficult in wild-type basidiomycetes partially due to extremely low frequencies of homology directed recombination (HDR) and limited availability of selectable markers. To overcome these obstacles, we assessed various Cas9-single guide RNA (sgRNA) ribonucleoprotein (RNP) -based strategies for selectable homology and non-homologous end joining (NHEJ) -based gene editing in D. squalens. We also showed an induction of HDR-based genetic modifications by using single-stranded oligodeoxynucleotides (ssODNs) in a basidiomycete fungus for the first time. This paper provides directions for the application of targeted CRISPR/Cas9-based genome editing in D. squalens and other wild-type (basidiomycete) fungi.
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Affiliation(s)
| | | | - Miia R. Mäkelä
- Department of Microbiology, University of Helsinki, Viikinkaari 9, 00790 Helsinki, Finland; (J.E.K.); (S.S.)
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62
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Singh NK, Karisto P, Croll D. Population-level deep sequencing reveals the interplay of clonal and sexual reproduction in the fungal wheat pathogen Zymoseptoria tritici. Microb Genom 2021; 7. [PMID: 34617882 PMCID: PMC8627204 DOI: 10.1099/mgen.0.000678] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pathogens cause significant challenges to global food security. On annual crops, pathogens must re-infect from environmental sources in every growing season. Fungal pathogens have evolved mixed reproductive strategies to cope with the distinct challenges of colonizing growing plants. However, how pathogen diversity evolves during growing seasons remains largely unknown. Here, we performed a deep hierarchical sampling in a single experimental wheat field infected by the major fungal pathogen Zymoseptoria tritici. We analysed whole genome sequences of 177 isolates collected from 12 distinct cultivars replicated in space at three time points of the growing season to maximize capture of genetic diversity. The field population was highly diverse with 37 SNPs per kilobase, a linkage disequilibrium decay within 200-700 bp and a high effective population size. Using experimental infections, we tested a subset of the collected isolates on the dominant cultivar planted in the field. However, we found no significant difference in virulence of isolates collected from the same cultivar compared to isolates collected on other cultivars. About 20 % of the isolate genotypes were grouped into 15 clonal groups. Pairs of clones were disproportionally found at short distances (<5 m), consistent with experimental estimates for per-generation dispersal distances performed in the same field. This confirms predominant leaf-to-leaf transmission during the growing season. Surprisingly, levels of clonality did not increase over time in the field although reproduction is thought to be exclusively asexual during the growing season. Our study shows that the pathogen establishes vast and stable gene pools in single fields. Monitoring short-term evolutionary changes in crop pathogens will inform more durable strategies to contain diseases.
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Affiliation(s)
- Nikhil Kumar Singh
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Petteri Karisto
- Plant Health, Natural Resources Institute Finland (Luke), Jokioinen, Finland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
- *Correspondence: Daniel Croll,
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Epigenetic modifications affect the rate of spontaneous mutations in a pathogenic fungus. Nat Commun 2021; 12:5869. [PMID: 34620872 PMCID: PMC8497519 DOI: 10.1038/s41467-021-26108-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 09/17/2021] [Indexed: 12/17/2022] Open
Abstract
Mutations are the source of genetic variation and the substrate for evolution. Genome-wide mutation rates appear to be affected by selection and are probably adaptive. Mutation rates are also known to vary along genomes, possibly in response to epigenetic modifications, but causality is only assumed. In this study we determine the direct impact of epigenetic modifications and temperature stress on mitotic mutation rates in a fungal pathogen using a mutation accumulation approach. Deletion mutants lacking epigenetic modifications confirm that histone mark H3K27me3 increases whereas H3K9me3 decreases the mutation rate. Furthermore, cytosine methylation in transposable elements (TE) increases the mutation rate 15-fold resulting in significantly less TE mobilization. Also accessory chromosomes have significantly higher mutation rates. Finally, we find that temperature stress substantially elevates the mutation rate. Taken together, we find that epigenetic modifications and environmental conditions modify the rate and the location of spontaneous mutations in the genome and alter its evolutionary trajectory.
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64
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An automated and combinative method for the predictive ranking of candidate effector proteins of fungal plant pathogens. Sci Rep 2021; 11:19731. [PMID: 34611252 PMCID: PMC8492765 DOI: 10.1038/s41598-021-99363-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 09/16/2021] [Indexed: 01/29/2023] Open
Abstract
Fungal plant-pathogens promote infection of their hosts through the release of 'effectors'-a broad class of cytotoxic or virulence-promoting molecules. Effectors may be recognised by resistance or sensitivity receptors in the host, which can determine disease outcomes. Accurate prediction of effectors remains a major challenge in plant pathology, but if achieved will facilitate rapid improvements to host disease resistance. This study presents a novel tool and pipeline for the ranking of predicted effector candidates-Predector-which interfaces with multiple software tools and methods, aggregates disparate features that are relevant to fungal effector proteins, and applies a pairwise learning to rank approach. Predector outperformed a typical combination of secretion and effector prediction methods in terms of ranking performance when applied to a curated set of confirmed effectors derived from multiple species. We present Predector ( https://github.com/ccdmb/predector ) as a useful tool for the ranking of predicted effector candidates, which also aggregates and reports additional supporting information relevant to effector and secretome prediction in a simple, efficient, and reproducible manner.
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65
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Oggenfuss U, Badet T, Wicker T, Hartmann FE, Singh NK, Abraham L, Karisto P, Vonlanthen T, Mundt C, McDonald BA, Croll D. A population-level invasion by transposable elements triggers genome expansion in a fungal pathogen. eLife 2021; 10:e69249. [PMID: 34528512 PMCID: PMC8445621 DOI: 10.7554/elife.69249] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/28/2021] [Indexed: 12/16/2022] Open
Abstract
Genome evolution is driven by the activity of transposable elements (TEs). The spread of TEs can have deleterious effects including the destabilization of genome integrity and expansions. However, the precise triggers of genome expansions remain poorly understood because genome size evolution is typically investigated only among deeply divergent lineages. Here, we use a large population genomics dataset of 284 individuals from populations across the globe of Zymoseptoria tritici, a major fungal wheat pathogen. We built a robust map of genome-wide TE insertions and deletions to track a total of 2456 polymorphic loci within the species. We show that purifying selection substantially depressed TE frequencies in most populations, but some rare TEs have recently risen in frequency and likely confer benefits. We found that specific TE families have undergone a substantial genome-wide expansion from the pathogen's center of origin to more recently founded populations. The most dramatic increase in TE insertions occurred between a pair of North American populations collected in the same field at an interval of 25 years. We find that both genome-wide counts of TE insertions and genome size have increased with colonization bottlenecks. Hence, the demographic history likely played a major role in shaping genome evolution within the species. We show that both the activation of specific TEs and relaxed purifying selection underpin this incipient expansion of the genome. Our study establishes a model to recapitulate TE-driven genome evolution over deeper evolutionary timescales.
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Affiliation(s)
- Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Thomas Wicker
- Institute for Plant and Microbial Biology, University of ZurichZurichSwitzerland
| | - Fanny E Hartmann
- Ecologie Systématique Evolution, Bâtiment 360, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-SaclayOrsayFrance
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Nikhil Kumar Singh
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Leen Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Petteri Karisto
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Tiziana Vonlanthen
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Christopher Mundt
- Department of Botany and Plant Pathology, Oregon State UniversityCorvallisUnited States
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
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Fouché G, Michel T, Lalève A, Wang NX, Young DH, Meunier B, Debieu D, Fillinger S, Walker AS. Directed evolution predicts cytochrome b G37V target site modification as probable adaptive mechanism towards the QiI fungicide fenpicoxamid in Zymoseptoria tritici. Environ Microbiol 2021; 24:1117-1132. [PMID: 34490974 DOI: 10.1111/1462-2920.15760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/03/2021] [Accepted: 09/04/2021] [Indexed: 02/06/2023]
Abstract
Acquired resistance is a threat to antifungal efficacy in medicine and agriculture. The diversity of possible resistance mechanisms and highly adaptive traits of pathogens make it difficult to predict evolutionary outcomes of treatments. We used directed evolution as an approach to assess the resistance risk to the new fungicide fenpicoxamid in the wheat pathogenic fungus Zymoseptoria tritici. Fenpicoxamid inhibits complex III of the respiratory chain at the ubiquinone reduction site (Qi site) of the mitochondrially encoded cytochrome b, a different site than the widely used strobilurins which inhibit the same complex at the ubiquinol oxidation site (Qo site). We identified the G37V change within the cytochrome b Qi site as the most likely resistance mechanism to be selected in Z. tritici. This change triggered high fenpicoxamid resistance and halved the enzymatic activity of cytochrome b, despite no significant penalty for in vitro growth. We identified negative cross-resistance between isolates harbouring G37V or G143A, a Qo site change previously selected by strobilurins. Double mutants were less resistant to both QiIs and quinone outside inhibitors compared to single mutants. This work is a proof of concept that experimental evolution can be used to predict adaptation to fungicides and provides new perspectives for the management of QiIs.
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Affiliation(s)
- Guillaume Fouché
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, Thiverval-Grignon, 78850, France.,Corteva Agriscience, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Thomas Michel
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91198, France
| | - Anaïs Lalève
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, Thiverval-Grignon, 78850, France
| | - Nick X Wang
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - David H Young
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Brigitte Meunier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91198, France
| | - Danièle Debieu
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, Thiverval-Grignon, 78850, France
| | - Sabine Fillinger
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, Thiverval-Grignon, 78850, France
| | - Anne-Sophie Walker
- Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, Thiverval-Grignon, 78850, France
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67
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Fouché S, Oggenfuss U, Chanclud E, Croll D. A devil's bargain with transposable elements in plant pathogens. Trends Genet 2021; 38:222-230. [PMID: 34489138 DOI: 10.1016/j.tig.2021.08.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 02/08/2023]
Abstract
Transposable elements (TEs) spread in genomes through self-copying mechanisms and are a major cause of genome expansions. Plant pathogens have finely tuned the expression of virulence factors to rely on epigenetic control targeted at nearby TEs. Stress experienced during the plant infection process leads to derepression of TEs and concurrently allows the expression of virulence factors. We argue that the derepression of TEs elements causes an evolutionary conflict by favoring TEs that can be reactivated. Active TEs and recent genome size expansions indicate that plant pathogens could face long-term consequences from the short-term benefit of fine-tuning the infection process. Hence, encoding key virulence factors close to TEs under epigenetic control constitutes a devil's bargain for pathogens.
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Affiliation(s)
- Simone Fouché
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland; Department of Organismal Biology - Systematic Biology, Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden
| | - Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Emilie Chanclud
- 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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Stephens C, Ölmez F, Blyth H, McDonald M, Bansal A, Turgay EB, Hahn F, Saintenac C, Nekrasov V, Solomon P, Milgate A, Fraaije B, Rudd J, Kanyuka K. Remarkable recent changes in the genetic diversity of the avirulence gene AvrStb6 in global populations of the wheat pathogen Zymoseptoria tritici. MOLECULAR PLANT PATHOLOGY 2021; 22:1121-1133. [PMID: 34258838 PMCID: PMC8358995 DOI: 10.1111/mpp.13101] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 04/02/2021] [Accepted: 06/03/2021] [Indexed: 06/13/2023]
Abstract
Septoria tritici blotch (STB), caused by the fungus Zymoseptoria tritici, is one of the most economically important diseases of wheat. Recently, both factors of a gene-for-gene interaction between Z. tritici and wheat, the wheat receptor-like kinase Stb6 and the Z. tritici secreted effector protein AvrStb6, have been identified. Previous analyses revealed a high diversity of AvrStb6 haplotypes present in earlier Z. tritici isolate collections, with up to c.18% of analysed isolates possessing the avirulence isoform of AvrStb6 identical to that originally identified in the reference isolate IPO323. With Stb6 present in many commercial wheat cultivars globally, we aimed to assess potential changes in AvrStb6 genetic diversity and the incidence of haplotypes allowing evasion of Stb6-mediated resistance in more recent Z. tritici populations. Here we show, using targeted resequencing of AvrStb6, that this gene is universally present in field isolates sampled from major wheat-growing regions of the world in 2013-2017. However, in contrast to the data from previous AvrStb6 population studies, we report a complete absence of the originally described avirulence isoform of AvrStb6 amongst modern Z. tritici isolates. Moreover, a remarkably small number of haplotypes, each encoding AvrStb6 protein isoforms conditioning virulence on Stb6-containing wheat, were found to predominate among modern Z. tritici isolates. A single virulence isoform of AvrStb6 was found to be particularly abundant throughout the global population. These findings indicate that, despite the ability of Z. tritici to sexually reproduce on resistant hosts, AvrStb6 avirulence haplotypes tend to be eliminated in subsequent populations.
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Affiliation(s)
| | - Fatih Ölmez
- Department of Plant ProtectionSivas Science and Technology UniversitySivasTurkey
| | - Hannah Blyth
- Department of Biointeractions and Crop ProtectionRothamsted ResearchHarpendenUK
| | - Megan McDonald
- Division of Plant SciencesResearch School of BiologyAustralian National UniversityCanberraAustralia
- Present address:
Megan McDonald, School of BiosciencesUniversity of BirminghamBirminghamUK
| | - Anuradha Bansal
- Department of Biointeractions and Crop ProtectionRothamsted ResearchHarpendenUK
- Present address:
British American TobaccoSouthamptonUK
| | - Emine Burcu Turgay
- Department of Plant PathologyPlant Protection Central Research InstituteField Crops Central Research InstituteAnkaraTurkey
| | - Florian Hahn
- Department of Plant SciencesRothamsted ResearchHarpendenUK
- Present address:
Department of Plant SciencesUniversity of OxfordOxfordUK
| | | | | | - Peter Solomon
- Division of Plant SciencesResearch School of BiologyAustralian National UniversityCanberraAustralia
| | - Andrew Milgate
- NSW Department of Primary IndustriesWagga Wagga Agricultural InstituteWagga WaggaAustralia
| | - Bart Fraaije
- Department of Biointeractions and Crop ProtectionRothamsted ResearchHarpendenUK
- Present address:
NIABCambridgeUK
| | - Jason Rudd
- Department of Biointeractions and Crop ProtectionRothamsted ResearchHarpendenUK
| | - Kostya Kanyuka
- Department of Biointeractions and Crop ProtectionRothamsted ResearchHarpendenUK
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The Role of Glycoside Hydrolases in Phytopathogenic Fungi and Oomycetes Virulence. Int J Mol Sci 2021; 22:ijms22179359. [PMID: 34502268 PMCID: PMC8431085 DOI: 10.3390/ijms22179359] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 01/11/2023] Open
Abstract
Phytopathogenic fungi need to secrete different hydrolytic enzymes to break down complex polysaccharides in the plant cell wall in order to enter the host and develop the disease. Fungi produce various types of cell wall degrading enzymes (CWDEs) during infection. Most of the characterized CWDEs belong to glycoside hydrolases (GHs). These enzymes hydrolyze glycosidic bonds and have been identified in many fungal species sequenced to date. Many studies have shown that CWDEs belong to several GH families and play significant roles in the invasion and pathogenicity of fungi and oomycetes during infection on the plant host, but their mode of function in virulence is not yet fully understood. Moreover, some of the CWDEs that belong to different GH families act as pathogen-associated molecular patterns (PAMPs), which trigger plant immune responses. In this review, we summarize the most important GHs that have been described in eukaryotic phytopathogens and are involved in the establishment of a successful infection.
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70
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Weisberg AJ, Grünwald NJ, Savory EA, Putnam ML, Chang JH. Genomic Approaches to Plant-Pathogen Epidemiology and Diagnostics. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:311-332. [PMID: 34030448 DOI: 10.1146/annurev-phyto-020620-121736] [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: 06/12/2023]
Abstract
Diseases have a significant cost to agriculture. Findings from analyses of whole-genome sequences show great promise for informing strategies to mitigate risks from diseases caused by phytopathogens. Genomic approaches can be used to dramatically shorten response times to outbreaks and inform disease management in novel ways. However, the use of these approaches requires expertise in working with big, complex data sets and an understanding of their pitfalls and limitations to infer well-supported conclusions. We suggest using an evolutionary framework to guide the use of genomic approaches in epidemiology and diagnostics of plant pathogens. We also describe steps that are necessary for realizing these as standard approaches in disease surveillance.
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Affiliation(s)
- Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
| | - Niklaus J Grünwald
- Horticultural Crops Research Laboratory, USDA Agricultural Research Service, Corvallis, Oregon 97331, USA
| | | | - Melodie L Putnam
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
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71
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Chethana KWT, Jayawardena RS, Chen YJ, Konta S, Tibpromma S, Phukhamsakda C, Abeywickrama PD, Samarakoon MC, Senwanna C, Mapook A, Tang X, Gomdola D, Marasinghe DS, Padaruth OD, Balasuriya A, Xu J, Lumyong S, Hyde KD. Appressorial interactions with host and their evolution. FUNGAL DIVERS 2021. [DOI: 10.1007/s13225-021-00487-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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72
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Nagel JH, Wingfield MJ, Slippers B. Increased abundance of secreted hydrolytic enzymes and secondary metabolite gene clusters define the genomes of latent plant pathogens in the Botryosphaeriaceae. BMC Genomics 2021; 22:589. [PMID: 34348651 PMCID: PMC8336260 DOI: 10.1186/s12864-021-07902-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 06/30/2021] [Indexed: 01/11/2023] Open
Abstract
Background The Botryosphaeriaceae are important plant pathogens, but also have the ability to establish asymptomatic infections that persist for extended periods in a latent state. In this study, we used comparative genome analyses to shed light on the genetic basis of the interactions of these fungi with their plant hosts. For this purpose, we characterised secreted hydrolytic enzymes, secondary metabolite biosynthetic gene clusters and general trends in genomic architecture using all available Botryosphaeriaceae genomes, and selected Dothideomycetes genomes. Results The Botryosphaeriaceae genomes were rich in carbohydrate-active enzymes (CAZymes), proteases, lipases and secondary metabolic biosynthetic gene clusters (BGCs) compared to other Dothideomycete genomes. The genomes of Botryosphaeria, Macrophomina, Lasiodiplodia and Neofusicoccum, in particular, had gene expansions of the major constituents of the secretome, notably CAZymes involved in plant cell wall degradation. The Botryosphaeriaceae genomes were shown to have moderate to high GC contents and most had low levels of repetitive DNA. The genomes were not compartmentalized based on gene and repeat densities, but genes of secreted enzymes were slightly more abundant in gene-sparse regions. Conclusion The abundance of secreted hydrolytic enzymes and secondary metabolite BGCs in the genomes of Botryosphaeria, Macrophomina, Lasiodiplodia, and Neofusicoccum were similar to those in necrotrophic plant pathogens and some endophytes of woody plants. The results provide a foundation for comparative genomic analyses and hypotheses to explore the mechanisms underlying Botryosphaeriaceae host-plant interactions. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07902-w.
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Affiliation(s)
- Jan H Nagel
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0001, South Africa.
| | - Michael J Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0001, South Africa
| | - Bernard Slippers
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0001, South Africa
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73
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Zhou X, Li J, Tang N, Xie H, Fan X, Chen H, Tang M, Xie X. Genome-Wide Analysis of Nutrient Signaling Pathways Conserved in Arbuscular Mycorrhizal Fungi. Microorganisms 2021; 9:1557. [PMID: 34442636 PMCID: PMC8401276 DOI: 10.3390/microorganisms9081557] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 01/03/2023] Open
Abstract
Arbuscular mycorrhizal (AM) fungi form a mutualistic symbiosis with a majority of terrestrial vascular plants. To achieve an efficient nutrient trade with their hosts, AM fungi sense external and internal nutrients, and integrate different hierarchic regulations to optimize nutrient acquisition and homeostasis during mycorrhization. However, the underlying molecular networks in AM fungi orchestrating the nutrient sensing and signaling remain elusive. Based on homology search, we here found that at least 72 gene components involved in four nutrient sensing and signaling pathways, including cAMP-dependent protein kinase A (cAMP-PKA), sucrose non-fermenting 1 (SNF1) protein kinase, target of rapamycin kinase (TOR) and phosphate (PHO) signaling cascades, are well conserved in AM fungi. Based on the knowledge known in model yeast and filamentous fungi, we outlined the possible gene networks functioning in AM fungi. These pathways may regulate the expression of downstream genes involved in nutrient transport, lipid metabolism, trehalase activity, stress resistance and autophagy. The RNA-seq analysis and qRT-PCR results of some core genes further indicate that these pathways may play important roles in spore germination, appressorium formation, arbuscule longevity and sporulation of AM fungi. We hope to inspire further studies on the roles of these candidate genes involved in these nutrient sensing and signaling pathways in AM fungi and AM symbiosis.
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Affiliation(s)
- Xiaoqin Zhou
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Lingnan Guangdong Laboratory of Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (X.Z.); (H.X.); (X.F.); (H.C.)
| | - Jiangyong Li
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China;
| | - Nianwu Tang
- UMR Interactions Arbres/Microorganismes, Centre INRA-Grand Est-Nancy, 54280 Champenoux, France;
| | - Hongyun Xie
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Lingnan Guangdong Laboratory of Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (X.Z.); (H.X.); (X.F.); (H.C.)
| | - Xiaoning Fan
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Lingnan Guangdong Laboratory of Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (X.Z.); (H.X.); (X.F.); (H.C.)
| | - Hui Chen
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Lingnan Guangdong Laboratory of Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (X.Z.); (H.X.); (X.F.); (H.C.)
| | - Ming Tang
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Lingnan Guangdong Laboratory of Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (X.Z.); (H.X.); (X.F.); (H.C.)
| | - Xianan Xie
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Lingnan Guangdong Laboratory of Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (X.Z.); (H.X.); (X.F.); (H.C.)
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74
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Fagundes WC, Haueisen J, Stukenbrock EH. Dissecting the Biology of the Fungal Wheat Pathogen Zymoseptoria tritici: A Laboratory Workflow. ACTA ACUST UNITED AC 2021; 59:e128. [PMID: 33175475 DOI: 10.1002/cpmc.128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The fungus Zymoseptoria tritici is one of the most devastating pathogens of wheat. Aside from its importance as a disease-causing agent, this species has emerged as a powerful model system for evolutionary genetic studies of crop-infecting fungal pathogens. Z. tritici exhibits exceptionally high levels of genetic and phenotypic diversity as well as morphological plasticity, which can make experimental studies and comparability of results obtained in different laboratories, e.g., from infection assays, challenging. Therefore, standardized experimental methods are crucial for research on Z. tritici biology and the interaction of this fungus with its wheat host. Here, we describe a suite of well-tested and optimized protocols ranging from isolation of Z. tritici field specimens to analyses of virulence assays under controlled conditions. Several biological and technical aspects of working with Z. tritici under laboratory conditions are considered and carefully described in each protocol. © 2020 The Authors. Basic Protocol 1: Purification of Z. tritici field isolates from leaf material Basic Protocol 2: Molecular identification of Z. tritici isolates Support Protocol 1: Rapid extraction of Z. tritici genomic DNA Support Protocol 2: Extraction of high-quality Z. tritici genomic DNA Basic Protocol 3: In vitro culture and long-term storage of Z. tritici isolates Basic Protocol 4: Analysis of Z. tritici virulence in wheat Support Protocol 3: Preparation of Z. tritici inoculum.
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Affiliation(s)
- Wagner C Fagundes
- Environmental Genomics Group, Christian-Albrechts University Kiel, Kiel, Germany.,Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Janine Haueisen
- Environmental Genomics Group, Christian-Albrechts University Kiel, Kiel, Germany.,Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Eva H Stukenbrock
- Environmental Genomics Group, Christian-Albrechts University Kiel, Kiel, Germany.,Max Planck Institute for Evolutionary Biology, Plön, Germany
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75
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Lorrain C, Feurtey A, Möller M, Haueisen J, Stukenbrock E. Dynamics of transposable elements in recently diverged fungal pathogens: lineage-specific transposable element content and efficiency of genome defenses. G3-GENES GENOMES GENETICS 2021; 11:6173990. [PMID: 33724368 PMCID: PMC8759822 DOI: 10.1093/g3journal/jkab068] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/19/2021] [Indexed: 01/29/2023]
Abstract
Transposable elements (TEs) impact genome plasticity, architecture, and evolution in fungal plant pathogens. The wide range of TE content observed in fungal genomes reflects diverse efficacy of host-genome defense mechanisms that can counter-balance TE expansion and spread. Closely related species can harbor drastically different TE repertoires. The evolution of fungal effectors, which are crucial determinants of pathogenicity, has been linked to the activity of TEs in pathogen genomes. Here, we describe how TEs have shaped genome evolution of the fungal wheat pathogen Zymoseptoria tritici and four closely related species. We compared de novo TE annotations and repeat-induced point mutation signatures in 26 genomes from the Zymoseptoria species-complex. Then, we assessed the relative insertion ages of TEs using a comparative genomics approach. Finally, we explored the impact of TE insertions on genome architecture and plasticity. The 26 genomes of Zymoseptoria species reflect different TE dynamics with a majority of recent insertions. TEs associate with accessory genome compartments, with chromosomal rearrangements, with gene presence/absence variation, and with effectors in all Zymoseptoria species. We find that the extent of RIP-like signatures varies among Z. tritici genomes compared to genomes of the sister species. The detection of a reduction of RIP-like signatures and TE recent insertions in Z. tritici reflects ongoing but still moderate TE mobility.
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Affiliation(s)
- Cécile Lorrain
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, Kiel 24118, Germany.,Université de Lorraine/INRAE, UMR 1136 Interactions Arbres/Microorganismes, INRAE Centre Grand Est-Nancy, Champenoux 54280, France
| | - Alice Feurtey
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, Kiel 24118, Germany
| | - Mareike Möller
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, Kiel 24118, Germany
| | - Janine Haueisen
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, Kiel 24118, Germany
| | - Eva Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, Kiel 24118, Germany
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76
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Wang C, Milgate AW, Solomon PS, McDonald MC. The identification of a transposon affecting the asexual reproduction of the wheat pathogen Zymoseptoria tritici. MOLECULAR PLANT PATHOLOGY 2021; 22:800-816. [PMID: 33949756 PMCID: PMC8232023 DOI: 10.1111/mpp.13064] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 05/13/2023]
Abstract
Zymoseptoria tritici, the causal agent of Septoria tritici blotch, is a fungal wheat pathogen that causes significant global yield losses. Within Z. tritici populations, quantitative differences in virulence among different isolates are commonly observed; however, the genetic components that underpin these differences remain elusive. In this study, intraspecific comparative transcriptomic analysis was used to identify candidate genes that contribute to differences in virulence on the wheat cultivar WW2449. This led to the identification of a multicopy gene that was not expressed in the high-virulence isolate when compared to the medium- and low-virulence isolates. Further investigation suggested this gene resides in a 7.9-kb transposon. Subsequent long-read sequencing of the isolates used in the transcriptomic analysis confirmed that this gene did reside in an active Class II transposon, which is composed of four genes named REP9-1 to -4. Silencing and overexpression of REP9-1 in two distinct genetic backgrounds demonstrated that its expression alone reduces the number of pycnidia produced by Z. tritici during infection. The REP9-1 gene identified within a Class II transposon is the first discovery of a gene in a transposable element that influences the virulence of Z. tritici. This discovery adds further complexity to genetic loci that contribute to quantitative virulence in this important pathogen.
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Affiliation(s)
- Chen Wang
- Division of Plant SciencesResearch School of BiologyThe Australian National UniversityCanberraACTAustralia
| | - Andrew W. Milgate
- NSW Department of Primary IndustriesWagga Wagga Agricultural InstituteWagga WaggaNSWAustralia
| | - Peter S. Solomon
- Division of Plant SciencesResearch School of BiologyThe Australian National UniversityCanberraACTAustralia
| | - Megan C. McDonald
- Division of Plant SciencesResearch School of BiologyThe Australian National UniversityCanberraACTAustralia
- School of BiosciencesUniversity of BirminghamEdgbastonBirminghamUK
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77
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Habig M, Schotanus K, Hufnagel K, Happel P, Stukenbrock EH. Ago1 Affects the Virulence of the Fungal Plant Pathogen Zymoseptoria tritici. Genes (Basel) 2021; 12:1011. [PMID: 34208898 PMCID: PMC8303167 DOI: 10.3390/genes12071011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/23/2021] [Accepted: 06/28/2021] [Indexed: 12/04/2022] Open
Abstract
In host-pathogen interactions RNA interference (RNAi) has emerged as a pivotal mechanism to modify both, the immune responses of the host as well as the pathogenicity and virulence of the pathogen. In addition, in some fungi RNAi is also known to affect chromosome biology via its effect on chromatin conformation. Previous studies reported no effect of the RNAi machinery on the virulence of the fungal plant pathogen Zymoseptoria tritici however the role of RNAi is still poorly understood in this species. Herein, we elucidate whether the RNAi machinery is conserved within the genus Zymoseptoria. Moreover, we conduct functional analyses of Argonaute and Dicer-like proteins and test if the RNAi machinery affects chromosome stability. We show that the RNAi machinery is conserved among closely related Zymoseptoria species while an exceptional pattern of allelic diversity was possibly caused by introgression. The deletion of Ago1 reduced the ability of the fungus to produce asexual propagules in planta in a quantitative matter. Chromosome stability of the accessory chromosome of Z. tritici was not prominently affected by the RNAi machinery. These results indicate, in contrast to previous finding, a role of the RNAi pathway during host infection, but not in the stability of accessory chromosomes in Z. tritici.
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Affiliation(s)
- Michael Habig
- Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 1-11, 24118 Kiel, Germany; (M.H.); (K.S.); (K.H.)
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Klaas Schotanus
- Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 1-11, 24118 Kiel, Germany; (M.H.); (K.S.); (K.H.)
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Kim Hufnagel
- Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 1-11, 24118 Kiel, Germany; (M.H.); (K.S.); (K.H.)
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Petra Happel
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany;
| | - Eva H. Stukenbrock
- Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 1-11, 24118 Kiel, Germany; (M.H.); (K.S.); (K.H.)
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
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78
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Hage H, Rosso MN, Tarrago L. Distribution of methionine sulfoxide reductases in fungi and conservation of the free-methionine-R-sulfoxide reductase in multicellular eukaryotes. Free Radic Biol Med 2021; 169:187-215. [PMID: 33865960 DOI: 10.1016/j.freeradbiomed.2021.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 12/17/2022]
Abstract
Methionine, either as a free amino acid or included in proteins, can be oxidized into methionine sulfoxide (MetO), which exists as R and S diastereomers. Almost all characterized organisms possess thiol-oxidoreductases named methionine sulfoxide reductase (Msr) enzymes to reduce MetO back to Met. MsrA and MsrB reduce the S and R diastereomers of MetO, respectively, with strict stereospecificity and are found in almost all organisms. Another type of thiol-oxidoreductase, the free-methionine-R-sulfoxide reductase (fRMsr), identified so far in prokaryotes and a few unicellular eukaryotes, reduces the R MetO diastereomer of the free amino acid. Moreover, some bacteria possess molybdenum-containing enzymes that reduce MetO, either in the free or protein-bound forms. All these Msrs play important roles in the protection of organisms against oxidative stress. Fungi are heterotrophic eukaryotes that colonize all niches on Earth and play fundamental functions, in organic matter recycling, as symbionts, or as pathogens of numerous organisms. However, our knowledge on fungal Msrs is still limited. Here, we performed a survey of msr genes in almost 700 genomes across the fungal kingdom. We show that most fungi possess one gene coding for each type of methionine sulfoxide reductase: MsrA, MsrB, and fRMsr. However, several fungi living in anaerobic environments or as obligate intracellular parasites were devoid of msr genes. Sequence inspection and phylogenetic analyses allowed us to identify non-canonical sequences with potentially novel enzymatic properties. Finaly, we identified several ocurences of msr horizontal gene transfer from bacteria to fungi.
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Affiliation(s)
- Hayat Hage
- Biodiversité et Biotechnologie Fongiques, UMR1163, INRAE, Aix Marseille Université, Marseille, France
| | - Marie-Noëlle Rosso
- Biodiversité et Biotechnologie Fongiques, UMR1163, INRAE, Aix Marseille Université, Marseille, France
| | - Lionel Tarrago
- Biodiversité et Biotechnologie Fongiques, UMR1163, INRAE, Aix Marseille Université, Marseille, France.
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79
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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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80
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Genome assembly of Scorias spongiosa and comparative genomics provide insights into ecological adaptation of honeydew-dependent sooty mould fungi. Genomics 2021; 113:2189-2198. [PMID: 34022339 DOI: 10.1016/j.ygeno.2021.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 03/04/2021] [Accepted: 05/17/2021] [Indexed: 12/28/2022]
Abstract
Sooty moulds are fungi of economic importance and with unique lifestyle mainly growing on insect honeydew. However, the lack of genomic data hinders investigation of genetic mechanisms underlying their ecological adaptation. With long-read sequencing technology, we generated the genome of Scorias spongiosa, an extraordinary sooty mould fungus associated with honeydew of colony aphids and producing large fruiting bodies. A 24.21 Mb high-quality genome assembly with a N50 length of 3.37 Mb was obtained. The genome contained 7758 protein coding genes, 97.13% of which were homologous to known genes, and approximately 0.29 Mb repeat sequences. Comparative genomics showed S. spongiosa lost relatively more gene families and contained fewer species-specific genes and gene families, with many CAZyme families and sugar transporters reduced or absent. This study not only promotes understanding of the ecological adaptation of sooty moulds, but also provides valuable genomic data resource for future comparative genomic and genetic studies.
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81
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Dutta A, Hartmann FE, Francisco CS, McDonald BA, Croll D. Mapping the adaptive landscape of a major agricultural pathogen reveals evolutionary constraints across heterogeneous environments. THE ISME JOURNAL 2021; 15:1402-1419. [PMID: 33452474 PMCID: PMC8115182 DOI: 10.1038/s41396-020-00859-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/17/2020] [Accepted: 11/24/2020] [Indexed: 02/06/2023]
Abstract
The adaptive potential of pathogens in novel or heterogeneous environments underpins the risk of disease epidemics. Antagonistic pleiotropy or differential resource allocation among life-history traits can constrain pathogen adaptation. However, we lack understanding of how the genetic architecture of individual traits can generate trade-offs. Here, we report a large-scale study based on 145 global strains of the fungal wheat pathogen Zymoseptoria tritici from four continents. We measured 50 life-history traits, including virulence and reproduction on 12 different wheat hosts and growth responses to several abiotic stressors. To elucidate the genetic basis of adaptation, we used genome-wide association mapping coupled with genetic correlation analyses. We show that most traits are governed by polygenic architectures and are highly heritable suggesting that adaptation proceeds mainly through allele frequency shifts at many loci. We identified negative genetic correlations among traits related to host colonization and survival in stressful environments. Such genetic constraints indicate that pleiotropic effects could limit the pathogen's ability to cause host damage. In contrast, adaptation to abiotic stress factors was likely facilitated by synergistic pleiotropy. Our study illustrates how comprehensive mapping of life-history trait architectures across diverse environments allows to predict evolutionary trajectories of pathogens confronted with environmental perturbations.
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Affiliation(s)
- Anik Dutta
- grid.5801.c0000 0001 2156 2780Plant Pathology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Fanny E. Hartmann
- grid.5801.c0000 0001 2156 2780Plant Pathology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland ,grid.417885.70000 0001 2185 8223Ecologie Systématique Evolution, CNRS, Université Paris-Saclay, AgroParisTech, 91400 Orsay, France
| | - Carolina Sardinha Francisco
- grid.5801.c0000 0001 2156 2780Plant Pathology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland ,Present Address: Environmental Genomics Group, Botanical Institute, CAU Kiel, Germany
| | - Bruce A. McDonald
- grid.5801.c0000 0001 2156 2780Plant Pathology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Daniel Croll
- grid.10711.360000 0001 2297 7718Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
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82
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Gluck-Thaler E, Haridas S, Binder M, Grigoriev IV, Crous PW, Spatafora JW, Bushley K, Slot JC. The Architecture of Metabolism Maximizes Biosynthetic Diversity in the Largest Class of Fungi. Mol Biol Evol 2021; 37:2838-2856. [PMID: 32421770 PMCID: PMC7530617 DOI: 10.1093/molbev/msaa122] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ecological diversity in fungi is largely defined by metabolic traits, including the ability to produce secondary or “specialized” metabolites (SMs) that mediate interactions with other organisms. Fungal SM pathways are frequently encoded in biosynthetic gene clusters (BGCs), which facilitate the identification and characterization of metabolic pathways. Variation in BGC composition reflects the diversity of their SM products. Recent studies have documented surprising diversity of BGC repertoires among isolates of the same fungal species, yet little is known about how this population-level variation is inherited across macroevolutionary timescales. Here, we applied a novel linkage-based algorithm to reveal previously unexplored dimensions of diversity in BGC composition, distribution, and repertoire across 101 species of Dothideomycetes, which are considered the most phylogenetically diverse class of fungi and known to produce many SMs. We predicted both complementary and overlapping sets of clustered genes compared with existing methods and identified novel gene pairs that associate with known secondary metabolite genes. We found that variation among sets of BGCs in individual genomes is due to nonoverlapping BGC combinations and that several BGCs have biased ecological distributions, consistent with niche-specific selection. We observed that total BGC diversity scales linearly with increasing repertoire size, suggesting that secondary metabolites have little structural redundancy in individual fungi. We project that there is substantial unsampled BGC diversity across specific families of Dothideomycetes, which will provide a roadmap for future sampling efforts. Our approach and findings lend new insight into how BGC diversity is generated and maintained across an entire fungal taxonomic class.
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Affiliation(s)
- Emile Gluck-Thaler
- Department of Plant Pathology, The Ohio State University, Columbus, OH.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | - Sajeet Haridas
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA
| | | | - Igor V Grigoriev
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA
| | - Pedro W Crous
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - Joseph W Spatafora
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR
| | - Kathryn Bushley
- Department of Plant and Microbial Biology, University of Minnesota, Minneapolis, MN
| | - Jason C Slot
- Department of Plant Pathology, The Ohio State University, Columbus, OH
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83
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Möller M, Habig M, Lorrain C, Feurtey A, Haueisen J, Fagundes WC, Alizadeh A, Freitag M, Stukenbrock EH. Recent loss of the Dim2 DNA methyltransferase decreases mutation rate in repeats and changes evolutionary trajectory in a fungal pathogen. PLoS Genet 2021; 17:e1009448. [PMID: 33750960 PMCID: PMC8016269 DOI: 10.1371/journal.pgen.1009448] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 04/01/2021] [Accepted: 02/26/2021] [Indexed: 01/04/2023] Open
Abstract
DNA methylation is found throughout all domains of life, yet the extent and function of DNA methylation differ among eukaryotes. Strains of the plant pathogenic fungus Zymoseptoria tritici appeared to lack cytosine DNA methylation (5mC) because gene amplification followed by Repeat-Induced Point mutation (RIP) resulted in the inactivation of the dim2 DNA methyltransferase gene. 5mC is, however, present in closely related sister species. We demonstrate that inactivation of dim2 occurred recently as some Z. tritici isolates carry a functional dim2 gene. Moreover, we show that dim2 inactivation occurred by a different path than previously hypothesized. We mapped the genome-wide distribution of 5mC in strains with or without functional dim2 alleles. Presence of functional dim2 correlates with high levels of 5mC in transposable elements (TEs), suggesting a role in genome defense. We identified low levels of 5mC in strains carrying non-functional dim2 alleles, suggesting that 5mC is maintained over time, presumably by an active Dnmt5 DNA methyltransferase. Integration of a functional dim2 allele in strains with mutated dim2 restored normal 5mC levels, demonstrating de novo cytosine methylation activity of Dim2. To assess the importance of 5mC for genome evolution, we performed an evolution experiment, comparing genomes of strains with high levels of 5mC to genomes of strains lacking functional dim2. We found that presence of a functional dim2 allele alters nucleotide composition by promoting C to T transitions (C→T) specifically at CpA (CA) sites during mitosis, likely contributing to TE inactivation. Our results show that 5mC density at TEs is a polymorphic trait in Z. tritici populations that can impact genome evolution.
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Affiliation(s)
- Mareike Möller
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Michael Habig
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Cécile Lorrain
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alice Feurtey
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Janine Haueisen
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Wagner C. Fagundes
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alireza Alizadeh
- Department of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University, Tabriz, Iran
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States of America
| | - Eva H. Stukenbrock
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
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84
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Hu M, Chen S. Non-Target Site Mechanisms of Fungicide Resistance in Crop Pathogens: A Review. Microorganisms 2021; 9:microorganisms9030502. [PMID: 33673517 PMCID: PMC7997439 DOI: 10.3390/microorganisms9030502] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/18/2021] [Accepted: 02/23/2021] [Indexed: 01/15/2023] Open
Abstract
The rapid emergence of resistance in plant pathogens to the limited number of chemical classes of fungicides challenges sustainability and profitability of crop production worldwide. Understanding mechanisms underlying fungicide resistance facilitates monitoring of resistant populations at large-scale, and can guide and accelerate the development of novel fungicides. A majority of modern fungicides act to disrupt a biochemical function via binding a specific target protein in the pathway. While target-site based mechanisms such as alternation and overexpression of target genes have been commonly found to confer resistance across many fungal species, it is not uncommon to encounter resistant phenotypes without altered or overexpressed target sites. However, such non-target site mechanisms are relatively understudied, due in part to the complexity of the fungal genome network. This type of resistance can oftentimes be transient and noninheritable, further hindering research efforts. In this review, we focused on crop pathogens and summarized reported mechanisms of resistance that are otherwise related to target-sites, including increased activity of efflux pumps, metabolic circumvention, detoxification, standing genetic variations, regulation of stress response pathways, and single nucleotide polymorphisms (SNPs) or mutations. In addition, novel mechanisms of drug resistance recently characterized in human pathogens are reviewed in the context of nontarget-directed resistance.
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Affiliation(s)
- Mengjun Hu
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA
- Correspondence: (M.H.); (S.C.)
| | - Shuning Chen
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Correspondence: (M.H.); (S.C.)
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85
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Genomic rearrangements generate hypervariable mini-chromosomes in host-specific isolates of the blast fungus. PLoS Genet 2021; 17:e1009386. [PMID: 33591993 PMCID: PMC7909708 DOI: 10.1371/journal.pgen.1009386] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/26/2021] [Accepted: 01/26/2021] [Indexed: 12/11/2022] Open
Abstract
Supernumerary mini-chromosomes–a unique type of genomic structural variation–have been implicated in the emergence of virulence traits in plant pathogenic fungi. However, the mechanisms that facilitate the emergence and maintenance of mini-chromosomes across fungi remain poorly understood. In the blast fungus Magnaporthe oryzae (Syn. Pyricularia oryzae), mini-chromosomes have been first described in the early 1990s but, until very recently, have been overlooked in genomic studies. Here we investigated structural variation in four isolates of the blast fungus M. oryzae from different grass hosts and analyzed the sequences of mini-chromosomes in the rice, foxtail millet and goosegrass isolates. The mini-chromosomes of these isolates turned out to be highly diverse with distinct sequence composition. They are enriched in repetitive elements and have lower gene density than core-chromosomes. We identified several virulence-related genes in the mini-chromosome of the rice isolate, including the virulence-related polyketide synthase Ace1 and two variants of the effector gene AVR-Pik. Macrosynteny analyses around these loci revealed structural rearrangements, including inter-chromosomal translocations between core- and mini-chromosomes. Our findings provide evidence that mini-chromosomes emerge from structural rearrangements and segmental duplication of core-chromosomes and might contribute to adaptive evolution of the blast fungus. The genomes of plant pathogens often exhibit an architecture that facilitates high rates of dynamic rearrangements and genetic diversification in virulence associated regions. These regions, which tend to be gene sparse and repeat rich, are thought to serve as a cradle for adaptive evolution. Supernumerary chromosomes, i.e. chromosomes that are only present in some but not all individuals of a species, are a special type of structural variation that have been observed in plants, animals, and fungi. Here we identified and studied supernumerary mini-chromosomes in the blast fungus Magnaporthe oryzae, a pathogen that causes some of the most destructive plant diseases. We found that rice, foxtail millet and goosegrass isolates of this pathogen contain mini-chromosomes with distinct sequence composition. All mini-chromosomes are rich in repetitive genetic elements and have lower gene densities than core-chromosomes. Further, we identified virulence-related genes on the mini-chromosome of the rice isolate. We observed large-scale genomic rearrangements around these loci, indicative of a role of mini-chromosomes in facilitating genome dynamics. Taken together, our results indicate that mini-chromosomes contribute to genome rearrangements and possibly adaptive evolution of the blast fungus.
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86
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Karki SJ, Reilly A, Zhou B, Mascarello M, Burke J, Doohan F, Douchkov D, Schweizer P, Feechan A. A small secreted protein from Zymoseptoria tritici interacts with a wheat E3 ubiquitin ligase to promote disease. JOURNAL OF EXPERIMENTAL BOTANY 2021. [PMID: 33095257 DOI: 10.5061/dryad.9w0vt4bcx] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria tritici, is a major threat to wheat production worldwide. The Z. tritici genome encodes many small secreted proteins (ZtSSPs) that are likely to play a key role in the successful colonization of host tissues. However, few of these ZtSSPs have been functionally characterized for their role during infection. In this study, we identified and characterized a small, conserved cysteine-rich secreted effector from Z. tritici which has homologues in other plant pathogens in the Dothideomycetes. ZtSSP2 was expressed throughout Z. tritici infection in wheat, with the highest levels observed early during infection. A yeast two-hybrid assay revealed an interaction between ZtSSP2 and wheat E3 ubiquitin ligase (TaE3UBQ) in yeast, and this was further confirmed in planta using bimolecular fluorescence complementation and co-immunoprecipitation. Down-regulation of this wheat E3 ligase using virus-induced gene silencing increased the susceptibility of wheat to STB. Together, these results suggest that TaE3UBQ is likely to play a role in plant immunity to defend against Z. tritici.
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Affiliation(s)
- Sujit Jung Karki
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Aisling Reilly
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Binbin Zhou
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Maurizio Mascarello
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
- Ecology, Evolution and Biodiversity Conservation, Charles Deberiotstraat 8 32, 3000 Leuven, Belgium
| | - James Burke
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Fiona Doohan
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dimitar Douchkov
- Institute of Plant Genetics and Crop Plant Research (IPK), Cytogenetics, Gatersleben, Germany
| | - Patrick Schweizer
- Institute of Plant Genetics and Crop Plant Research (IPK), Cytogenetics, Gatersleben, Germany
| | - Angela Feechan
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
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87
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Karki SJ, Reilly A, Zhou B, Mascarello M, Burke J, Doohan F, Douchkov D, Schweizer P, Feechan A. A small secreted protein from Zymoseptoria tritici interacts with a wheat E3 ubiquitin ligase to promote disease. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:733-746. [PMID: 33095257 PMCID: PMC7853600 DOI: 10.1093/jxb/eraa489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 10/15/2020] [Indexed: 05/05/2023]
Abstract
Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria tritici, is a major threat to wheat production worldwide. The Z. tritici genome encodes many small secreted proteins (ZtSSPs) that are likely to play a key role in the successful colonization of host tissues. However, few of these ZtSSPs have been functionally characterized for their role during infection. In this study, we identified and characterized a small, conserved cysteine-rich secreted effector from Z. tritici which has homologues in other plant pathogens in the Dothideomycetes. ZtSSP2 was expressed throughout Z. tritici infection in wheat, with the highest levels observed early during infection. A yeast two-hybrid assay revealed an interaction between ZtSSP2 and wheat E3 ubiquitin ligase (TaE3UBQ) in yeast, and this was further confirmed in planta using bimolecular fluorescence complementation and co-immunoprecipitation. Down-regulation of this wheat E3 ligase using virus-induced gene silencing increased the susceptibility of wheat to STB. Together, these results suggest that TaE3UBQ is likely to play a role in plant immunity to defend against Z. tritici.
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Affiliation(s)
- Sujit Jung Karki
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Aisling Reilly
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Binbin Zhou
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Maurizio Mascarello
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
- Ecology, Evolution and Biodiversity Conservation, Charles Deberiotstraat 8 32, 3000 Leuven, Belgium
| | - James Burke
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Fiona Doohan
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dimitar Douchkov
- Institute of Plant Genetics and Crop Plant Research (IPK), Cytogenetics, Gatersleben, Germany
| | - Patrick Schweizer
- Institute of Plant Genetics and Crop Plant Research (IPK), Cytogenetics, Gatersleben, Germany
| | - Angela Feechan
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
- Correspondence:
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88
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Fantozzi E, Kilaru S, Cannon S, Schuster M, Gurr SJ, Steinberg G. Conditional promoters to investigate gene function during wheat infection by Zymoseptoria tritici. Fungal Genet Biol 2021; 146:103487. [PMID: 33309991 PMCID: PMC7812376 DOI: 10.1016/j.fgb.2020.103487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/27/2022]
Abstract
The fungus Zymoseptoria tritici causes Septoria tritici leaf blotch, which poses a serious threat to temperate-grown wheat. Recently, we described a raft of molecular tools to study the biology of this fungus in vitro. Amongst these are 5 conditional promoters (Pnar1, Pex1A, Picl1, Pgal7, PlaraB), which allow controlled over-expression or repression of target genes in cells grown in liquid culture. However, their use in the host-pathogen interaction in planta was not tested. Here, we investigate the behaviour of these promoters by quantitative live cell imaging of green-fluorescent protein-expressing cells during 6 stages of the plant infection process. We show that Pnar1 and Picl1 are repressed in planta and demonstrate their suitability for studying essential gene expression and function in plant colonisation. The promoters Pgal7 and Pex1A are not fully-repressed in planta, but are induced during pycnidiation. This indicates the presence of inducing galactose or xylose and/or arabinose, released from the plant cell wall by the activity of fungal hydrolases. In contrast, the PlaraB promoter, which normally controls expression of an α-l-arabinofuranosidase B, is strongly induced inside the leaf. This suggests that the fungus is exposed to L-arabinose in the mesophyll apoplast. Taken together, this study establishes 2 repressible promoters (Pnar1 and Picl1) and three inducible promoters (Pgal7, Pex1A, PlaraB) for molecular studies in planta. Moreover, we provide circumstantial evidence for plant cell wall degradation during the biotrophic phase of Z. tritici infection.
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Affiliation(s)
- Elena Fantozzi
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Sreedhar Kilaru
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Stuart Cannon
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Martin Schuster
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Sarah J Gurr
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK; University of Utrecht, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Gero Steinberg
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK; University of Utrecht, Padualaan 8, Utrecht 3584 CH, the Netherlands.
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89
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Cook DE, Kramer HM, Torres DE, Seidl MF, Thomma BPHJ. A unique chromatin profile defines adaptive genomic regions in a fungal plant pathogen. eLife 2020; 9:e62208. [PMID: 33337321 PMCID: PMC7781603 DOI: 10.7554/elife.62208] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022] Open
Abstract
Genomes store information at scales beyond the linear nucleotide sequence, which impacts genome function at the level of an individual, while influences on populations and long-term genome function remains unclear. Here, we addressed how physical and chemical DNA characteristics influence genome evolution in the plant pathogenic fungus Verticillium dahliae. We identified incomplete DNA methylation of repetitive elements, associated with specific genomic compartments originally defined as Lineage-Specific (LS) regions that contain genes involved in host adaptation. Further chromatin characterization revealed associations with features such as H3 Lys-27 methylated histones (H3K27me3) and accessible DNA. Machine learning trained on chromatin data identified twice as much LS DNA as previously recognized, which was validated through orthogonal analysis, and we propose to refer to this DNA as adaptive genomic regions. Our results provide evidence that specific chromatin profiles define adaptive genomic regions, and highlight how different epigenetic factors contribute to the organization of these regions.
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Affiliation(s)
- David E Cook
- Department of Plant Pathology, Kansas State UniversityManhattanUnited States
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
| | - H Martin Kramer
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
| | - David E Torres
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht UniversityUtrechtNetherlands
| | - Michael F Seidl
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht UniversityUtrechtNetherlands
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
- University of Cologne, Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS)CologneGermany
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90
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Hartmann FE, Vonlanthen T, Singh NK, McDonald MC, Milgate A, Croll D. The complex genomic basis of rapid convergent adaptation to pesticides across continents in a fungal plant pathogen. Mol Ecol 2020; 30:5390-5405. [PMID: 33211369 DOI: 10.1111/mec.15737] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/30/2020] [Accepted: 11/12/2020] [Indexed: 12/12/2022]
Abstract
Convergent evolution leads to identical phenotypic traits in different species or populations. Convergence can be driven by standing variation allowing selection to favour identical alleles in parallel or the same mutations can arise independently. However, the molecular basis of such convergent adaptation remains often poorly resolved. Pesticide resistance in agricultural ecosystems is a hallmark of convergence in phenotypic traits. Here, we analyse the major fungal pathogen Zymoseptoria tritici causing serious losses on wheat and with fungicide resistance emergence across several continents. We sampled three population pairs each from a different continent spanning periods early and late in the application of fungicides. To identify causal loci for resistance, we combined knowledge from molecular genetics work and performed genome-wide association studies (GWAS) on a global set of isolates. We discovered yet unknown factors in azole resistance including a gene encoding membrane associated functions. We found strong support for the "hotspot" model of resistance evolution with convergent changes in a small set of loci but additional loci showed more population-specific allele frequency changes. Genome-wide scans of selection showed that half of all known resistance loci were overlapping a selective sweep region. Hence, the application of fungicides was one of the major selective agents acting on the pathogen over the past decades. Furthermore, loci identified through GWAS showed the highest overlap with selective sweep regions underlining the importance to map phenotypic trait variation in evolving populations. Our population genomic analyses highlighted that both de novo mutations and gene flow contributed to convergent pesticide adaptation.
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Affiliation(s)
- Fanny E Hartmann
- Ecologie Systematique Evolution, Batiment 360, Université Paris-Saclay, AgroParisTech, CNRS, Orsay, France.,Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Tiziana Vonlanthen
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.,Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Nikhil Kumar Singh
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Megan C McDonald
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, ACT, Australia.,School of Biosciences, University of Birmingham, Birmingham, UK
| | - Andrew Milgate
- NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, Australia
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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91
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Fones HN. Presence of ice-nucleating Pseudomonas on wheat leaves promotes Septoria tritici blotch disease (Zymoseptoria tritici) via a mutually beneficial interaction. Sci Rep 2020; 10:17738. [PMID: 33082401 PMCID: PMC7575590 DOI: 10.1038/s41598-020-74615-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 09/09/2020] [Indexed: 11/09/2022] Open
Abstract
Zymoseptoria tritici causes Septoria tritici blotch (STB) of wheat, an economically important disease causing yield losses of up to 10% despite the use of fungicides and resistant cultivars. Z. tritici infection is symptomless for around 10 days, during which time the fungus grows randomly across the leaf surface prior to entry through stomata. Wounded leaves show faster, more extensive STB, suggesting that wounds facilitate fungal entry. Wheat leaves also host epiphytic bacteria; these include ice-nucleating (INA+) bacteria, which induce frost damage at warmer temperatures than it otherwise occurs. Here, STB is shown to be more rapid and severe when wheat is exposed to both INA+ bacteria and sub-zero temperatures. This suggests that ice-nucleation-induced wounding of the wheat leaf provides additional openings for fungal entry. INA+ bacterial populations are shown to benefit from the presence of Z. tritici, indicating that this microbial interaction is mutualistic. Finally, control of INA+ bacteria is shown to reduce STB.
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Affiliation(s)
- Helen N Fones
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
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92
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Jallet AJ, Le Rouzic A, Genissel A. Evolution and Plasticity of the Transcriptome Under Temperature Fluctuations in the Fungal Plant Pathogen Zymoseptoria tritici. Front Microbiol 2020; 11:573829. [PMID: 33042084 PMCID: PMC7517895 DOI: 10.3389/fmicb.2020.573829] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/17/2020] [Indexed: 11/28/2022] Open
Abstract
Most species live in a variable environment in nature. Yet understanding the evolutionary processes underlying molecular adaptation to fluctuations remains a challenge. In this study we investigate the transcriptome of the fungal wheat pathogen Zymoseptoria tritici after experimental evolution under stable or fluctuating temperature, by comparing ancestral and evolved populations simultaneously. We found that temperature regimes could have a large and pervasive effect on the transcriptome evolution, with as much as 38% of the genes being differentially expressed between selection regimes. Although evolved lineages showed different changes of gene expression based on ancestral genotypes, we identified a set of genes responding specifically to fluctuation. We found that transcriptome evolution in fluctuating conditions was repeatable between parallel lineages initiated from the same genotype for about 60% of the differentially expressed genes. Further, we detected several hotspots of significantly differentially expressed genes in the genome, in regions known to be enriched in repetitive elements, including accessory chromosomes. Our findings also evidenced gene expression evolution toward a gain of robustness (loss of phenotypic plasticity) associated with the fluctuating regime, suggesting robustness is adaptive in changing environment. This work provides valuable insight into the role of transcriptional rewiring for rapid adaptation to abiotic changes in filamentous plant pathogens.
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Affiliation(s)
- Arthur J. Jallet
- UMR BIOGER, Université Paris Saclay – INRAE – AgroParisTech, Thiverval-Grignon, France
| | - Arnaud Le Rouzic
- UMR Évolution, Génomes, Comportement et Écologie, Université Paris-Saclay – CNRS – IRD, Gif-sur-Yvette, France
| | - Anne Genissel
- UMR BIOGER, Université Paris Saclay – INRAE – AgroParisTech, Thiverval-Grignon, France
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93
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Benbow HR, Brennan CJ, Zhou B, Christodoulou T, Berry S, Uauy C, Mullins E, Doohan FM. Insights into the resistance of a synthetically-derived wheat to Septoria tritici blotch disease: less is more. BMC PLANT BIOLOGY 2020; 20:407. [PMID: 32883202 PMCID: PMC7469286 DOI: 10.1186/s12870-020-02612-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 08/18/2020] [Indexed: 05/30/2023]
Abstract
BACKGROUND Little is known about the initial, symptomless (latent) phase of the devastating wheat disease Septoria tritici blotch. However, speculations as to its impact on fungal success and disease severity in the field have suggested that a long latent phase is beneficial to the host and can reduce inoculum build up in the field over a growing season. The winter wheat cultivar Stigg is derived from a synthetic hexaploid wheat and contains introgressions from wild tetraploid wheat Triticum turgidum subsp. dicoccoides, which contribute to cv. Stigg's exceptional STB resistance, hallmarked by a long latent phase. We compared the early transcriptomic response to Zymoseptoria tritici of cv. Stigg to a susceptible wheat cultivar, to elucidate the mechanisms of and differences in pathogen recognition and disease response in these two hosts. RESULTS The STB-susceptible cultivar Longbow responds to Z. tritici infection with a stress response, including activation of hormone-responsive transcription factors, post translational modifications, and response to oxidative stress. The activation of key genes associated with these pathways in cv. Longbow was independently observed in a second susceptible wheat cultivar based on an independent gene expression study. By comparison, cv. Stigg is apathetic in response to STB, and appears to fail to activate a range of defence pathways that cv. Longbow employs. Stigg also displays some evidence of sub-genome bias in its response to Z. tritici infection, whereas the susceptible cv. Longbow shows even distribution of Z. tritici responsive genes across the three wheat sub-genomes. CONCLUSIONS We identify a suite of disease response genes that are involved in early pathogen response in susceptible wheat cultivars that may ultimately lead to susceptibility. In comparison, we hypothesise that rather than an active defence response to stave off disease progression, cv. Stigg's defence strategy is molecular lethargy, or a lower-amplitude of pathogen recognition that may stem from cv. Stigg's wild wheat-derived ancestry. Overall, we present insights into cv. Stigg's exceptional resistance to STB, and present key biological processes for further characterisation in this pathosystem.
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Affiliation(s)
- Harriet R Benbow
- UCD School of Biology and Environmental Science, University College Dublin, UCD Belfield, Dublin 4, Ireland
- UCD Earth Institute, University College Dublin, UCD Belfield, Dublin 4, Ireland
- UCD Centre for Plant Science, University College Dublin, UCD Belfield, Dublin 4, Ireland
| | - Ciarán J Brennan
- UCD School of Biology and Environmental Science, University College Dublin, UCD Belfield, Dublin 4, Ireland
- UCD Earth Institute, University College Dublin, UCD Belfield, Dublin 4, Ireland
- UCD Centre for Plant Science, University College Dublin, UCD Belfield, Dublin 4, Ireland
| | - Binbin Zhou
- UCD School of Biology and Environmental Science, University College Dublin, UCD Belfield, Dublin 4, Ireland
- UCD Earth Institute, University College Dublin, UCD Belfield, Dublin 4, Ireland
- UCD Centre for Plant Science, University College Dublin, UCD Belfield, Dublin 4, Ireland
| | - Thalia Christodoulou
- UCD School of Biology and Environmental Science, University College Dublin, UCD Belfield, Dublin 4, Ireland
- UCD Earth Institute, University College Dublin, UCD Belfield, Dublin 4, Ireland
- UCD Centre for Plant Science, University College Dublin, UCD Belfield, Dublin 4, Ireland
| | - Simon Berry
- Limagrain UK Ltd, Windmill Avenue, Woolpit, Suffolk, IP30 9UP, UK
| | | | - Ewen Mullins
- Teagasc Crops Research, Oak Park, Co. Carlow, Ireland
| | - Fiona M Doohan
- UCD School of Biology and Environmental Science, University College Dublin, UCD Belfield, Dublin 4, Ireland.
- UCD Earth Institute, University College Dublin, UCD Belfield, Dublin 4, Ireland.
- UCD Centre for Plant Science, University College Dublin, UCD Belfield, Dublin 4, Ireland.
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94
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Torres DE, Oggenfuss U, Croll D, Seidl MF. Genome evolution in fungal plant pathogens: looking beyond the two-speed genome model. FUNGAL BIOL REV 2020. [DOI: 10.1016/j.fbr.2020.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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95
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Abstract
Most genomes within the species complex of Fusarium oxysporum are organized into two compartments: the core chromosomes (CCs) and accessory chromosomes (ACs). As opposed to CCs, which are conserved and vertically transmitted to carry out essential housekeeping functions, lineage- or strain-specific ACs are believed to be initially horizontally acquired through unclear mechanisms. These two genomic compartments are different in terms of gene density, the distribution of transposable elements, and epigenetic markers. Although common in eukaryotes, the functional importance of ACs is uniquely emphasized among fungal species, specifically in relationship to fungal pathogenicity and their adaptation to diverse hosts. With a focus on the cross-kingdom fungal pathogen F. oxysporum, this review provides a summary of the differences between CCs and ACs based on current knowledge of gene functions, genome structures, and epigenetic signatures, and explores the transcriptional crosstalk between the core and accessory genomes.
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96
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Feurtey A, Lorrain C, Croll D, Eschenbrenner C, Freitag M, Habig M, Haueisen J, Möller M, Schotanus K, Stukenbrock EH. Genome compartmentalization predates species divergence in the plant pathogen genus Zymoseptoria. BMC Genomics 2020; 21:588. [PMID: 32842972 PMCID: PMC7448473 DOI: 10.1186/s12864-020-06871-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 06/26/2020] [Indexed: 11/25/2022] Open
Abstract
Background Antagonistic co-evolution can drive rapid adaptation in pathogens and shape genome architecture. Comparative genome analyses of several fungal pathogens revealed highly variable genomes, for many species characterized by specific repeat-rich genome compartments with exceptionally high sequence variability. Dynamic genome structure may enable fast adaptation to host genetics. The wheat pathogen Zymoseptoria tritici with its highly variable genome, has emerged as a model organism to study genome evolution of plant pathogens. Here, we compared genomes of Z. tritici isolates and of sister species infecting wild grasses to address the evolution of genome composition and structure. Results Using long-read technology, we sequenced and assembled genomes of Z. ardabiliae, Z. brevis, Z. pseudotritici and Z. passerinii, together with two isolates of Z. tritici. We report a high extent of genome collinearity among Zymoseptoria species and high conservation of genomic, transcriptomic and epigenomic signatures of compartmentalization. We identify high gene content variability both within and between species. In addition, such variability is mainly limited to the accessory chromosomes and accessory compartments. Despite strong host specificity and non-overlapping host-range between species, predicted effectors are mainly shared among Zymoseptoria species, yet exhibiting a high level of presence-absence polymorphism within Z. tritici. Using in planta transcriptomic data from Z. tritici, we suggest different roles for the shared orthologs and for the accessory genes during infection of their hosts. Conclusion Despite previous reports of high genomic plasticity in Z. tritici, we describe here a high level of conservation in genomic, epigenomic and transcriptomic composition and structure across the genus Zymoseptoria. The compartmentalized genome allows the maintenance of a functional core genome co-occurring with a highly variable accessory genome.
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Affiliation(s)
- Alice Feurtey
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Cécile Lorrain
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany. .,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany. .,INRA Centre Grand Est - Nancy, UMR 1136 INRA/Universite de Lorraine Interactions Arbres/Microorganismes, 54280, Champenoux, France.
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Christoph Eschenbrenner
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Michael Habig
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Janine Haueisen
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Mareike Möller
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany.,Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Klaas Schotanus
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany.,Department of Molecular Genetics and Microbiology, Duke University, Duke University Medical Center, Durham, NC, 27710, USA
| | - Eva H Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
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97
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Riaz A, KockAppelgren P, Hehir JG, Kang J, Meade F, Cockram J, Milbourne D, Spink J, Mullins E, Byrne S. Genetic Analysis Using a Multi-Parent Wheat Population Identifies Novel Sources of Septoria Tritici Blotch Resistance. Genes (Basel) 2020; 11:E887. [PMID: 32759792 PMCID: PMC7465482 DOI: 10.3390/genes11080887] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/31/2020] [Accepted: 07/31/2020] [Indexed: 12/12/2022] Open
Abstract
Zymoseptoria tritici is the causative fungal pathogen of septoria tritici blotch (STB) disease of wheat (Triticum aestivum L.) that continuously threatens wheat crops in Ireland and throughout Europe. Under favorable conditions, STB can cause up to 50% yield losses if left untreated. STB is commonly controlled with fungicides; however, a combination of Z. tritici populations developing fungicide resistance and increased restrictions on fungicide use in the EU has led to farmers relying on fewer active substances. Consequently, this serves to drive the emergence of Z. tritici resistance against the remaining chemistries. In response, the use of resistant wheat varieties provides a more sustainable disease management strategy. However, the number of varieties offering an adequate level of resistance against STB is limited. Therefore, new sources of resistance or improved stacking of existing resistance loci are needed to develop varieties with superior agronomic performance. Here, we identified quantitative trait loci (QTL) for STB resistance in the eight-founder "NIAB Elite MAGIC" winter wheat population. The population was screened for STB response in the field under natural infection for three seasons from 2016 to 2018. Twenty-five QTL associated with STB resistance were identified in total. QTL either co-located with previously reported QTL or represent new loci underpinning STB resistance. The genomic regions identified and the linked genetic markers serve as useful resources for STB resistance breeding, supporting rapid selection of favorable alleles for the breeding of new wheat cultivars with improved STB resistance.
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Affiliation(s)
- Adnan Riaz
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
| | - Petra KockAppelgren
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
| | - James Gerard Hehir
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
| | - Jie Kang
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
- AgResearch, Invermay Agricultural Centre, Private Bag, Mosgiel 50034, New Zealand
- Department of Mathematics and Statistics, University of Otago, Dunedin 9016, New Zealand
| | - Fergus Meade
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
| | - James Cockram
- The John Bingham Laboratory, NIAB, Cambridge CB3 0LE, UK;
| | - Dan Milbourne
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
| | - John Spink
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
| | - Ewen Mullins
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
| | - Stephen Byrne
- Teagasc, Crop Science Department, Oak Park, R93 XE12 Carlow, Ireland; (A.R.); (P.K.); (J.G.H.); (J.K.); (F.M.); (D.M.); (J.S.); (E.M.)
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98
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Abstract
Diversity within the fungal kingdom is evident from the wide range of morphologies fungi display as well as the various ecological roles and industrial purposes they serve. Technological advances, particularly in long-read sequencing, coupled with the increasing efficiency and decreasing costs across sequencing platforms have enabled robust characterization of fungal genomes. These sequencing efforts continue to reveal the rampant diversity in fungi at the genome level. Here, we discuss studies that have furthered our understanding of fungal genetic diversity and genomic evolution. These studies revealed the presence of both small-scale and large-scale genomic changes. In fungi, research has recently focused on many small-scale changes, such as how hypermutation and allelic transmission impact genome evolution as well as how and why a few specific genomic regions are more susceptible to rapid evolution than others. High-throughput sequencing of a diverse set of fungal genomes has also illuminated the frequency, mechanisms, and impacts of large-scale changes, which include chromosome structural variation and changes in chromosome number, such as aneuploidy, polyploidy, and the presence of supernumerary chromosomes. The studies discussed herein have provided great insight into how the architecture of the fungal genome varies within species and across the kingdom and how modern fungi may have evolved from the last common fungal ancestor and might also pave the way for understanding how genomic diversity has evolved in all domains of life.
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Affiliation(s)
- Shelby J. Priest
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
| | - Vikas Yadav
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
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99
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McCorison CB, Goodwin SB. The wheat pathogen Zymoseptoria tritici senses and responds to different wavelengths of light. BMC Genomics 2020; 21:513. [PMID: 32711450 PMCID: PMC7382159 DOI: 10.1186/s12864-020-06899-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 07/08/2020] [Indexed: 12/30/2022] Open
Abstract
Background The ascomycete fungus Zymoseptoria tritici (synonyms: Mycosphaerella graminicola, Septoria tritici) is a major pathogen of wheat that causes the economically important foliar disease Septoria tritici blotch. Despite its importance as a pathogen, little is known about the reaction of this fungus to light. To test for light responses, cultures of Z. tritici were grown in vitro for 16-h days under white, blue or red light, and their transcriptomes were compared with each other and to those obtained from control cultures grown in darkness. Results There were major differences in gene expression with over 3400 genes upregulated in one or more of the light conditions compared to dark, and from 1909 to 2573 genes specifically upregulated in the dark compared to the individual light treatments. Differences between light treatments were lower, ranging from only 79 differentially expressed genes in the red versus blue comparison to 585 between white light and red. Many of the differentially expressed genes had no functional annotations. For those that did, analysis of the Gene Ontology (GO) terms showed that those related to metabolism were enriched in all three light treatments, while those related to growth and communication were more prevalent in the dark. Interestingly, genes for effectors that have been shown previously to be involved in pathogenicity also were upregulated in one or more of the light treatments, suggesting a possible role of light for infection. Conclusions This analysis shows that Z. tritici can sense and respond to light with a huge effect on transcript abundance. High proportions of differentially expressed genes with no functional annotations illuminates the huge gap in our understanding of light responses in this fungus. Differential expression of genes for effectors indicates that light could be important for pathogenicity; unknown effectors may show a similar pattern of transcription. A better understanding of the effects of light on pathogenicity and other biological processes of Z. tritici could help to manage Septoria tritici blotch in the future.
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Affiliation(s)
- Cassandra B McCorison
- Department of Botany and Plant Pathology, Purdue University, 915 West State Street, West Lafayette, IN, 47907-2054, USA
| | - Stephen B Goodwin
- USDA-Agricultural Research Service, Crop Production and Pest Control Research Unit, Department of Botany and Plant Pathology, Purdue University, 915 West State Street, West Lafayette, IN, 47907-2054, USA.
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100
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Deng Y, Zhang X, Xie B, Lin L, Hsiang T, Lin X, Lin Y, Zhang X, Ma Y, Miao W, Ming R. Intra-specific comparison of mitochondrial genomes reveals host gene fragment exchange via intron mobility in Tremella fuciformis. BMC Genomics 2020; 21:426. [PMID: 32580700 PMCID: PMC7315562 DOI: 10.1186/s12864-020-06846-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/17/2020] [Indexed: 01/21/2023] Open
Abstract
Background Mitochondrial genomic sequences are known to be variable. Comparative analyses of mitochondrial genomes can reveal the nature and extent of their variation. Results Draft mitochondrial genomes of 16 Tremella fuciformis isolates (TF01-TF16) were assembled from Illumina and PacBio sequencing data. Mitochondrial DNA contigs were extracted and assembled into complete circular molecules, ranging from 35,104 bp to 49,044 bp in size. All mtDNAs contained the same set of 41 conserved genes with identical gene order. Comparative analyses revealed that introns and intergenic regions were variable, whereas genic regions (including coding sequences, tRNA, and rRNA genes) were conserved. Among 24 introns detected, 11 were in protein-coding genes, 3 in tRNA genes, and the other 10 in rRNA genes. In addition, two mobile fragments were found in intergenic regions. Interestingly, six introns containing N-terminal duplication of the host genes were found in five conserved protein-coding gene sequences. Comparison of genes with and without these introns gave rise to the following proposed model: gene fragment exchange with other species can occur via gain or loss of introns with N-terminal duplication of the host genes. Conclusions Our findings suggest a novel mechanism of fungal mitochondrial gene evolution: partial foreign gene replacement though intron mobility.
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Affiliation(s)
- Youjin Deng
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Department of Plant Biology, University of Illinois at Urbana-Champaign, 1201 W. Gregory Drive, Urbana, IL, 61801, USA
| | - Xunxiao Zhang
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Baogui Xie
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Longji Lin
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Tom Hsiang
- Environmental Sciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Xiangzhi Lin
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yiying Lin
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xingtan Zhang
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yanhong Ma
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wenjing Miao
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Ray Ming
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,Department of Plant Biology, University of Illinois at Urbana-Champaign, 1201 W. Gregory Drive, Urbana, IL, 61801, USA.
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