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Guo Y, Krasnow CS, Hausbeck MK. Characterizing the Dynamics of Virulence and Fungicide Resistance of Phytophthora capsici in Michigan Vegetable Fields Reveals Loci Associated with Virulence. PLANT DISEASE 2024; 108:332-341. [PMID: 37656035 DOI: 10.1094/pdis-03-23-0576-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The oomycete Phytophthora capsici is a destructive pathogen infecting more than 50 plant species and is one of the most serious threats to cucurbit production. Phytophthora blight caused by Phytophthora capsici can affect all plant growth stages, and fungicides and cultural controls are used to limit losses. Dissecting pathogen virulence and fungicide resistance can provide insights into pathogenic mechanisms and inform effective management practices to control P. capsici. In this study, we assessed virulence, mefenoxam sensitivity, and genetic diversity of nine P. capsici populations collected from Cucurbitaceae, Solanaceae, and Fabaceae host families in Michigan from 2002 to 2016. We developed 992 simple sequence repeats (SSRs) in the P. capsici genome and identified 60 SSRs located within or close to RXLR-class (Arginine-any amino acid-Leucine-Arginine) effectors and 29 SSRs within or close to effector CRN (CRinkling and Necrosis) family protein, which represent 62 RXLR and 34 putative CRNs. Population structure analysis shows that mefenoxam resistance was not associated with the year of collection, host type, or location, but there were significant differences in virulence among the populations. Using the general linear model and mixed linear model-based association analyses with all effector-related SSR markers, we identified four SSR markers significantly associated with at least one of the virulence-related parameters. Of these, one (Pce_SC18) was in a predicted CRN effector and had high identity with the putative PhCRN37 effector in the pathogen Plasmopara halstedii, which can be further verified for virulence identification in P. capsici.
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Affiliation(s)
- Yufang Guo
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI
| | - Charles S Krasnow
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI
| | - Mary K Hausbeck
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI
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2
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Quesada-Ocampo LM, Parada-Rojas CH, Hansen Z, Vogel G, Smart C, Hausbeck MK, Carmo RM, Huitema E, Naegele RP, Kousik CS, Tandy P, Lamour K. Phytophthora capsici: Recent Progress on Fundamental Biology and Disease Management 100 Years After Its Description. ANNUAL REVIEW OF PHYTOPATHOLOGY 2023; 61:185-208. [PMID: 37257056 DOI: 10.1146/annurev-phyto-021622-103801] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Phytophthora capsici is a destructive oomycete pathogen of vegetable, ornamental, and tropical crops. First described by L.H. Leonian in 1922 as a pathogen of pepper in New Mexico, USA, P. capsici is now widespread in temperate and tropical countries alike. Phytophthora capsici is notorious for its capability to evade disease management strategies. High genetic diversity allows P. capsici populations to overcome fungicides and host resistance, the formation of oospores results in long-term persistence in soils, zoospore differentiation in the presence of water increases epidemic potential, and a broad host range maximizes economic losses and limits the effectiveness of crop rotation. The severity of disease caused by P. capsici and management challenges have led to numerous research efforts in the past 100 years. Here, we discuss recent findings regarding the biology, genetic diversity, disease management, fungicide resistance, host resistance, genomics, and effector biology of P. capsici.
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Affiliation(s)
- L M Quesada-Ocampo
- Department of Entomology and Plant Pathology and NC Plant Sciences Initiative, North Carolina State University, Raleigh, North Carolina, USA;
| | - C H Parada-Rojas
- Department of Entomology and Plant Pathology and NC Plant Sciences Initiative, North Carolina State University, Raleigh, North Carolina, USA;
| | - Z Hansen
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, USA
| | - G Vogel
- School of Integrative Plant Science, Cornell University, Geneva, New York, USA
| | - C Smart
- School of Integrative Plant Science, Cornell University, Geneva, New York, USA
| | - M K Hausbeck
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA
| | - R M Carmo
- Division of Plant Sciences, University of Dundee, Dundee, United Kingdom
| | - E Huitema
- Division of Plant Sciences, University of Dundee, Dundee, United Kingdom
- James Hutton Institute, Invergowrie, Dundee, United Kingdom
| | - R P Naegele
- Sugarbeet and Bean Research Unit, USDA, ARS, East Lansing, Michigan, USA
| | - C S Kousik
- US Vegetable Laboratory, USDA, ARS, Charleston, South Carolina, USA
| | - P Tandy
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, USA
| | - K Lamour
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, USA
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3
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Vogel G, Giles G, Robbins KR, Gore MA, Smart CD. Quantitative Genetic Analysis of Interactions in the Pepper- Phytophthora capsici Pathosystem. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:1018-1033. [PMID: 35914305 DOI: 10.1094/mpmi-12-21-0307-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The development of pepper cultivars with durable resistance to the oomycete Phytophthora capsici has been challenging due to differential interactions between the species that allow certain pathogen isolates to cause disease on otherwise resistant host genotypes. Currently, little is known about the pathogen genes involved in these interactions. To investigate the genetic basis of P. capsici virulence on individual pepper genotypes, we inoculated sixteen pepper accessions, representing commercial varieties, sources of resistance, and host differentials, with 117 isolates of P. capsici, for a total of 1,864 host-pathogen combinations. Analysis of disease outcomes revealed a significant effect of inter-species genotype-by-genotype interactions, although these interactions were quantitative rather than qualitative in scale. Isolates were classified into five pathogen subpopulations, as determined by their genotypes at over 60,000 single-nucleotide polymorphisms (SNPs). While absolute virulence levels on certain pepper accessions significantly differed between subpopulations, a multivariate phenotype reflecting relative virulence levels on certain pepper genotypes compared with others showed the strongest association with pathogen subpopulation. A genome-wide association study (GWAS) identified four pathogen loci significantly associated with virulence, two of which colocalized with putative RXLR effector genes and another with a polygalacturonase gene cluster. All four loci appeared to represent broad-spectrum virulence genes, as significant SNPs demonstrated consistent effects regardless of the host genotype tested. Host genotype-specific virulence variants in P. capsici may be difficult to map via GWAS with all but excessively large sample sizes, perhaps controlled by genes of small effect or by multiple allelic variants that have arisen independently. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Gregory Vogel
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| | - Garrett Giles
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| | - Kelly R Robbins
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Michael A Gore
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Christine D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
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4
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Parada-Rojas CH, Quesada-Ocampo LM. Phytophthora capsici Populations Are Structured by Host, Geography, and Fluopicolide Sensitivity. PHYTOPATHOLOGY 2022; 112:1559-1567. [PMID: 35124972 DOI: 10.1094/phyto-09-21-0403-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Phytophthora capsici epidemics are propelled by warm temperatures and wet conditions. With temperatures and inland flooding in many locations worldwide expected to rise as a result of global climate change, understanding of population structure can help to inform management of P. capsici in the field and prevent devastating epidemics. Thus, we investigated the effect of host crop, geographical origin, fungicide sensitivity, and mating type on shaping the population structure of P. capsici in the eastern United States. Our fungicide in vitro assays identified the emergence of insensitive isolates for fluopicolide and mefenoxam. A set of 12 microsatellite markers proved informative to assign 157 P. capsici isolates to five distinct genetic clusters. Implementation of Bayesian structure, population differentiation, genetic diversity statistics, and index of association analysis, allowed us to identify population structure by host with some correspondence with genetic clusters for cucumber and squash isolates. We found weak population structure by state for geographically close isolates. In this study, we discovered that North Carolina populations stratify by fluopicolide sensitivity with insensitive isolates experiencing nonrandom mating. Our findings highlight the need for careful monitoring of local field populations, improved selection of relevant isolates for breeding efforts, and hypervigilant surveillance of resistance to different fungicides.
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Affiliation(s)
- Camilo H Parada-Rojas
- Department of Entomology and Plant Pathology, and NC Plant Sciences Initiative, North Carolina State University, Raleigh, NC 27695-7613
| | - Lina M Quesada-Ocampo
- Department of Entomology and Plant Pathology, and NC Plant Sciences Initiative, North Carolina State University, Raleigh, NC 27695-7613
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5
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Sudermann MA, McGilp L, Vogel G, Regnier M, Jaramillo AR, Smart CD. The Diversity of Passalora fulva Isolates Collected from Tomato Plants in U.S. High Tunnels. PHYTOPATHOLOGY 2022; 112:1350-1360. [PMID: 35021861 DOI: 10.1094/phyto-06-21-0244-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
High tunnels extend the growing season of high value crops, including tomatoes, but the environmental conditions within high tunnels favor the spread of the tomato leaf mold pathogen, Passalora fulva (syn. Cladosporium fulvum). Tomato leaf mold results in defoliation, and if severe, losses in yield. Despite substantial research, little is known regarding the genetic structure and diversity of populations of P. fulva associated with high tunnel tomato production in the United States. From 2016 to 2019, a total of 50 P. fulva isolates were collected from tomato leaf samples in high tunnels in the Northeast and Minnesota. Other Cladosporium species were also isolated from the leaf surfaces. Koch's postulates were conducted to confirm that P. fulva was the cause of the disease symptoms observed. Race determination experiments revealed that the isolates belonged to either race 0 (six isolates) or race 2 (44 isolates). Polymorphisms were identified within four previously characterized effector genes: Avr2, Avr4, Avr4e, and Avr9. The largest number of polymorphisms were observed for Avr2. Both mating type genes, MAT1-1-1 and MAT1-2-1, were present in the isolate collection. For further insights into the pathogen diversity, the 50 isolates were genotyped at 7,514 single-nucleotide polymorphism loci using genotyping-by-sequencing. Differentiation by region but not by year was observed. Within the collection of 50 isolates, there were 18 distinct genotypes. Information regarding P. fulva population diversity will enable better management recommendations for growers, as high tunnel production of tomatoes expands.
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Affiliation(s)
- Martha A Sudermann
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| | - Lillian McGilp
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Gregory Vogel
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Melissa Regnier
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
- Laboratory of Mycology and Phytopathology, Department of Biological Sciences, Universidad de los Andes, Bogotá 111711, Colombia
| | - Alejandra Rodríguez Jaramillo
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| | - Christine D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
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6
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Stauber L, Croll D, Prospero S. Temporal changes in pathogen diversity in a perennial plant-pathogen-hyperparasite system. Mol Ecol 2022; 31:2073-2088. [PMID: 35122694 PMCID: PMC9540319 DOI: 10.1111/mec.16386] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 01/26/2022] [Accepted: 01/31/2022] [Indexed: 11/27/2022]
Abstract
Hyperparasites can affect the evolution of pathosystems by influencing the stability of both pathogen and host populations. However, how pathogens of perennial hosts evolve in the presence of a hyperparasite has rarely been studied. Here, we investigated temporal changes in genetic diversity of the invasive chestnut blight pathogen Cryphonectria parasitica in the presence of its parasitic mycovirus Cryphonectria hypovirus 1 (CHV1). The virus reduces fungal virulence and represents an effective natural biocontrol agent against chestnut blight in Europe. We analysed genome-wide diversity and CHV1 prevalence in C. parasitica populations in southern Switzerland that were sampled twice at an interval of about 30 years. Overall, we found that both pathogen population structure and CHV1 prevalence were retained over time. The results suggest that recent bottlenecks have influenced the structure of C. parasitica populations in southern Switzerland. Strong balancing selection signals were found at a single vegetative incompatibility (vic) locus, consistent with negative frequency-dependent selection imposed by the vegetative incompatibility system. High levels of mating among related individuals (i.e., inbreeding) and genetic drift are probably at the origin of imbalanced allele ratios at vic loci and subsequently low vc type diversity. Virus infection rates were stable at ~30% over the study period and we found no significant impact of the virus on fungal population diversity. Consequently, the efficacy of CHV1-mediated biocontrol was probably retained.
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Affiliation(s)
- Lea Stauber
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)BirmensdorfSwitzerland
- Laboratory of Evolutionary GeneticsInstitute of BiologyUniversity of NeuchâtelNeuchâtelSwitzerland
- Department of Environmental SciencesUniversity of BaselBaselSwitzerland
| | - Daniel Croll
- Laboratory of Evolutionary GeneticsInstitute of BiologyUniversity of NeuchâtelNeuchâtelSwitzerland
| | - Simone Prospero
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)BirmensdorfSwitzerland
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7
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Muniz AC, Pimenta RJG, Cruz MV, Rodrigues JG, Buzatti RSDO, Heuertz M, Lemos‐Filho JP, Lovato MB. Hybrid zone of a tree in a Cerrado/Atlantic Forest ecotone as a hotspot of genetic diversity and conservation. Ecol Evol 2022; 12:e8540. [PMID: 35127043 PMCID: PMC8803295 DOI: 10.1002/ece3.8540] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 12/17/2021] [Indexed: 01/10/2023] Open
Abstract
The Cerrado, the largest Neotropical savanna, and the Brazilian Atlantic Forest form large ecotonal areas where savanna and forest habitats occupy adjacent patches with closely related species occurring side by side, providing opportunities for hybridization. Here, we investigated the evolutionary divergence between the savanna and forest ecotypes of the widely distributed tree Plathymenia reticulata (n = 233 individuals). Genetic structure analysis of P. reticulata was congruent with the recognition of two ecotypes, whose divergence captured the largest proportion of genetic variance in the data (F CT = 0.222 and F ST = 0.307). The ecotonal areas between the Cerrado and the Atlantic Forest constitute a hybrid zone in which a diversity of hybrid classes was observed, most of them corresponding to second-generation hybrids (F2) or backcrosses. Gene flow occurred mainly toward the forest ecotype. The genetic structure was congruent with isolation by environment, and environmental correlates of divergence were identified. The observed pattern of high genetic divergence between ecotypes may reflect an incipient speciation process in P. reticulata. The low genetic diversity of the P. reticulata forest ecotype indicate that it is threatened in areas with high habitat loss on Atlantic Forest. In addition, the high divergence from the savanna ecotype suggests it should be treated as a different unit of management. The high genetic diversity found in the ecotonal hybrid zone supports the view of ecotones as important areas for the origin and conservation of biodiversity in the Neotropics.
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Affiliation(s)
- André Carneiro Muniz
- Departamento de Genética, Ecologia e EvoluçãoUniversidade Federal de Minas GeraisBelo HorizonteBrazil
| | | | - Mariana Vargas Cruz
- Departamento de Genética, Ecologia e EvoluçãoUniversidade Federal de Minas GeraisBelo HorizonteBrazil
| | | | | | | | - José P. Lemos‐Filho
- Departamento de BotânicaUniversidade Federal de Minas GeraisBelo HorizonteBrazil
| | - Maria Bernadete Lovato
- Departamento de Genética, Ecologia e EvoluçãoUniversidade Federal de Minas GeraisBelo HorizonteBrazil
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8
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Pánek M, Střížková I, Zouhar M, Kudláček T, Tomšovský M. Mixed-Mating Model of Reproduction Revealed in European Phytophthora cactorum by ddRADseq and Effector Gene Sequence Data. Microorganisms 2021; 9:345. [PMID: 33578718 PMCID: PMC7916502 DOI: 10.3390/microorganisms9020345] [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: 01/12/2021] [Revised: 01/27/2021] [Accepted: 02/06/2021] [Indexed: 02/07/2023] Open
Abstract
A population study of Phytophthora cactorum was performed using ddRADseq sequence variation analysis completed by the analysis of effector genes-RXLR6, RXLR7 and SCR113. The population structure was described by F-statistics, heterozygosity, nucleotide diversity, number of private alleles, number of polymorphic sites, kinship coefficient and structure analysis. The population of P. cactorum in Europe seems to be structured into host-associated groups. The isolates from woody hosts are structured into four groups described previously, while isolates from strawberry form another group. The groups are diverse in effector gene composition and the frequency of outbreeding. When populations from strawberry were analysed, both asexual reproduction and occasional outbreeding confirmed by gene flow among distinct populations were detected. Therefore, distinct P. cactorum populations differ in the level of heterozygosity. The data support the theory of the mixed-mating model for P. cactorum, comprising frequent asexual behaviour and inbreeding alternating with occasional outbreeding. Because P. cactorum is not indigenous to Europe, such variability is probably caused by multiple introductions of different lineages from the area of its original distribution, and the different histories of sexual recombination and host adaptation of particular populations.
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Affiliation(s)
- Matěj Pánek
- Crop Research Institute, Team of Ecology and Diagnostics of Fungal Plant Pathogens, Drnovská 507/73, 161 06 Praha, Czech Republic;
| | - Ivana Střížková
- Crop Research Institute, Team of Ecology and Diagnostics of Fungal Plant Pathogens, Drnovská 507/73, 161 06 Praha, Czech Republic;
| | - Miloslav Zouhar
- Department of Plant Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences in Prague, Kamýcká 129, 165 00 Praha, Czech Republic;
| | - Tomáš Kudláček
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, CZ-613 00 Brno, Czech Republic; (T.K.); (M.T.)
| | - Michal Tomšovský
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, CZ-613 00 Brno, Czech Republic; (T.K.); (M.T.)
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9
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Gerstein AC, Sharp NP. The population genetics of ploidy change in unicellular fungi. FEMS Microbiol Rev 2021; 45:6121427. [PMID: 33503232 DOI: 10.1093/femsre/fuab006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/14/2021] [Indexed: 12/23/2022] Open
Abstract
Changes in ploidy are a significant type of genetic variation, describing the number of chromosome sets per cell. Ploidy evolves in natural populations, clinical populations, and lab experiments, particularly in fungi. Despite a long history of theoretical work on this topic, predicting how ploidy will evolve has proven difficult, as it is often unclear why one ploidy state outperforms another. Here, we review what is known about contemporary ploidy evolution in diverse fungal species through the lens of population genetics. As with typical genetic variants, ploidy evolution depends on the rate that new ploidy states arise by mutation, natural selection on alternative ploidy states, and random genetic drift. However, ploidy variation also has unique impacts on evolution, with the potential to alter chromosomal stability, the rate and patterns of point mutation, and the nature of selection on all loci in the genome. We discuss how ploidy evolution depends on these general and unique factors and highlight areas where additional experimental evidence is required to comprehensively explain the ploidy transitions observed in the field and the lab.
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Affiliation(s)
- Aleeza C Gerstein
- Dept. of Microbiology, Dept. of Statistics, University of Manitoba Canada
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10
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Vogel G, Gore MA, Smart CD. Genome-Wide Association Study in New York Phytophthora capsici Isolates Reveals Loci Involved in Mating Type and Mefenoxam Sensitivity. PHYTOPATHOLOGY 2021; 111:204-216. [PMID: 32539639 DOI: 10.1094/phyto-04-20-0112-fi] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Phytophthora capsici is a soilborne oomycete plant pathogen that causes severe vegetable crop losses in New York (NY) state and worldwide. This pathogen is difficult to manage, in part due to its production of long-lasting sexual spores and its tendency to quickly evolve fungicide resistance. We single nucleotide polymorphism (SNP) genotyped 252 P. capsici isolates, predominantly from NY, in order to conduct a genome-wide association study for mating type and mefenoxam sensitivity. The population structure and extent of chromosomal copy number variation in this collection of isolates were also characterized. Population structure analyses showed isolates largely clustered by the field site where they were collected, with values of FST between pairs of fields ranging from 0.10 to 0.31. Thirty-three isolates were putative aneuploids, demonstrating evidence for having up to four linkage groups present in more than two copies, and an additional two isolates appeared to be genome-wide triploids. Mating type was mapped to a region on scaffold 4, consistent with previous findings, and mefenoxam sensitivity was associated with several SNP markers at a novel locus on scaffold 62. We identified several candidate genes for mefenoxam sensitivity, including a homolog of yeast ribosome synthesis factor Rrp5, but failed to locate near the scaffold 62 locus any subunits of RNA polymerase I, the hypothesized target site of phenylamide fungicides in oomycetes. This work expands our knowledge of the population biology of P. capsici and provides a foundation for functional validation of candidate genes associated with epidemiologically important phenotypes.
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Affiliation(s)
- Gregory Vogel
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456
| | - Michael A Gore
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853
| | - Christine D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456
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11
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Dussert Y, Legrand L, Mazet ID, Couture C, Piron MC, Serre RF, Bouchez O, Mestre P, Toffolatti SL, Giraud T, Delmotte F. Identification of the First Oomycete Mating-type Locus Sequence in the Grapevine Downy Mildew Pathogen, Plasmopara viticola. Curr Biol 2020; 30:3897-3907.e4. [PMID: 32795448 DOI: 10.1016/j.cub.2020.07.057] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/02/2020] [Accepted: 07/16/2020] [Indexed: 02/02/2023]
Abstract
Mating types are self-incompatibility systems that promote outcrossing in plants, fungi, and oomycetes. Mating-type genes have been widely studied in plants and fungi but have yet to be identified in oomycetes, eukaryotic organisms closely related to brown algae that cause many destructive animal and plant diseases. We identified the mating-type locus of Plasmopara viticola, the oomycete responsible for grapevine downy mildew, one of the most damaging grapevine diseases worldwide. Using a genome-wide association approach, we identified a 570-kb repeat-rich non-recombining region controlling mating types, with two highly divergent alleles. We showed that one mating type was homozygous, whereas the other was heterozygous at this locus. The mating-type locus encompassed 40 genes, including one encoding a putative hormone receptor. Functional studies will, however, be required to validate the function of these genes and find the actual determinants of mating type. Our findings have fundamental implications for our understanding of the evolution of mating types, as they reveal a unique determinism involving an asymmetry of heterozygosity, as in sex chromosomes and unlike other mating-type systems. This identification of the mating-type locus in such an economically important crop pathogen also has applied implications, as outcrossing facilitates rapid evolution and resistance to harsh environmental conditions.
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Affiliation(s)
- Yann Dussert
- SAVE, INRAE, Bordeaux Sciences Agro, Université de Bordeaux, F-33140 Villenave d'Ornon, France.
| | - Ludovic Legrand
- LIPM, INRAE, Université de Toulouse, CNRS, Castanet-Tolosan, France
| | - Isabelle D Mazet
- SAVE, INRAE, Bordeaux Sciences Agro, Université de Bordeaux, F-33140 Villenave d'Ornon, France
| | - Carole Couture
- SAVE, INRAE, Bordeaux Sciences Agro, Université de Bordeaux, F-33140 Villenave d'Ornon, France
| | | | | | - Olivier Bouchez
- INRAE, US 1426 GeT-PlaGe, Genotoul, Castanet-Tolosan, France
| | - Pere Mestre
- SVQV, INRAE, Université de Strasbourg, F-68000 Colmar, France
| | - Silvia Laura Toffolatti
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milano, Italy
| | - Tatiana Giraud
- Ecologie Systematique et Evolution, CNRS, AgroParisTech, Universite Paris-Saclay, 91400 Orsay, France
| | - François Delmotte
- SAVE, INRAE, Bordeaux Sciences Agro, Université de Bordeaux, F-33140 Villenave d'Ornon, France.
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12
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Barchenger DW, Sheu ZM, Kumar S, Lin SW, Burlakoti RR, Bosland PW. Race Characterization of Phytophthora Root Rot on Capsicum in Taiwan as a Basis for Anticipatory Resistance Breeding. PHYTOPATHOLOGY 2018; 108:964-971. [PMID: 29484915 DOI: 10.1094/phyto-08-17-0289-r] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Peppers (Capsicum sp.) are an increasingly important crop because of their use as a vegetable, spice, and food colorant. The oomycete Phytophthora capsici is one of the most devastating pathogens to pepper production worldwide, causing more than $100 million in losses annually. Developing cultivars resistant to P. capsici is challenging because of the many physiological races that exist and new races that are continuously evolving. This problem is confounded by the lack of a universal system of race characterization. As a basis to develop a global anticipatory breeding program, New Mexico recombinant inbred lines (NMRILs) functioned as a host differential for Phytophthora root rot to characterize the race structure of P. capsici populations in Taiwan. Using the NMRILs, 24 new races were identified, illustrating the utility and usefulness of the NMRILs for anticipatory breeding. Virulence of P. capsici was observed to be geographically specific and in two virulence clusters. Interestingly, all but two isolates collected in 2016 were the A2 mating type, which is a shift from the predominantly A1 mating type isolates collected prior to 2008. The NMRILs host differential provides an approach for scientists to work together on a global scale when breeding for resistance as well as on a local level for regional gene deployment. Additionally, we propose that the current race numbering system, which has no biological meaning, be supplemented with the virulence phenotype, based on the susceptible NMRILs to a given isolate. This work provides insights into the population dynamics of P. capsici and interactions within the highly complex Capsicum-Phytophthora pathosystem, and offers a basis for similar research in other crops.
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Affiliation(s)
- Derek W Barchenger
- First and sixth authors: Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces; and first, second, third, fourth, and fifth: World Vegetable Center, Shanhua, Tainan, Taiwan
| | - Zong-Ming Sheu
- First and sixth authors: Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces; and first, second, third, fourth, and fifth: World Vegetable Center, Shanhua, Tainan, Taiwan
| | - Sanjeet Kumar
- First and sixth authors: Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces; and first, second, third, fourth, and fifth: World Vegetable Center, Shanhua, Tainan, Taiwan
| | - Shih-Wen Lin
- First and sixth authors: Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces; and first, second, third, fourth, and fifth: World Vegetable Center, Shanhua, Tainan, Taiwan
| | - Rishi R Burlakoti
- First and sixth authors: Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces; and first, second, third, fourth, and fifth: World Vegetable Center, Shanhua, Tainan, Taiwan
| | - Paul W Bosland
- First and sixth authors: Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces; and first, second, third, fourth, and fifth: World Vegetable Center, Shanhua, Tainan, Taiwan
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Barchenger DW, Lamour KH, Bosland PW. Challenges and Strategies for Breeding Resistance in Capsicum annuum to the Multifarious Pathogen, Phytophthora capsici. FRONTIERS IN PLANT SCIENCE 2018; 9:628. [PMID: 29868083 PMCID: PMC5962783 DOI: 10.3389/fpls.2018.00628] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 04/20/2018] [Indexed: 05/20/2023]
Abstract
Phytophthora capsici is the most devastating pathogen for chile pepper production worldwide and current management strategies are not effective. The population structure of the pathogen is highly variable and few sources of widely applicable host resistance have been identified. Recent genomic advancements in the host and the pathogen provide important insights into the difficulties reported by epidemiological and physiological studies published over the past century. This review highlights important challenges unique to this complex pathosystem and suggests strategies for resistance breeding to help limit losses associated with P. capsici.
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Affiliation(s)
- Derek W. Barchenger
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM, United States
| | - Kurt H. Lamour
- Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Paul W. Bosland
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM, United States
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14
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Genetic diversity of Phytophthora capsici recovered from Massachusetts between 1997 and 2014. Mycol Prog 2017. [DOI: 10.1007/s11557-017-1334-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Barchenger DW, Lamour KH, Sheu ZM, Shrestha S, Kumar S, Lin SW, Burlakoti R, Bosland PW. Intra- and Intergenomic variation of Ploidy and Clonality characterize Phytophthora capsici on Capsicum sp. in Taiwan. Mycol Prog 2017. [DOI: 10.1007/s11557-017-1330-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Phytophthora colocasiae from Vietnam, China, Hawaii and Nepal: intra- and inter-genomic variations in ploidy and a long-lived, diploid Hawaiian lineage. Mycol Prog 2017. [DOI: 10.1007/s11557-017-1323-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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