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Contreras-Soto MB, Tovar-Pedraza JM. Viruses of plant-pathogenic fungi: a promising biocontrol strategy for Sclerotinia sclerotiorum. Arch Microbiol 2023; 206:38. [PMID: 38142438 DOI: 10.1007/s00203-023-03774-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/17/2023] [Accepted: 11/26/2023] [Indexed: 12/26/2023]
Abstract
Plant pathogenic fungi pose a significant and ongoing threat to agriculture and food security, causing economic losses and significantly reducing crop yields. Effectively managing these fungal diseases is crucial for sustaining agricultural productivity, and in this context, mycoviruses have emerged as a promising biocontrol option. These viruses alter the physiology of their fungal hosts and their interactions with the host plants. This review encompasses the extensive diversity of reported mycoviruses, including their taxonomic classification and range of fungal hosts. We highlight representative examples of mycoviruses that affect economically significant plant-pathogenic fungi and their distinctive characteristics, with a particular emphasis on mycoviruses impacting Sclerotinia sclerotiorum. These mycoviruses exhibit significant potential for biocontrol, supported by their specificity, efficacy, and environmental safety. This positions mycoviruses as valuable tools in crop protection against diseases caused by this pathogen, maintaining their study and application as promising research areas in agricultural biotechnology. The remarkable diversity of mycoviruses, coupled with their ability to infect a broad range of plant-pathogenic fungi, inspires optimism, and suggests that these viruses have the potential to serve as an effective management strategy against major fungi-causing plant diseases worldwide.
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Affiliation(s)
- María Belia Contreras-Soto
- Laboratorio de Fitopatología, Centro de Investigación en Alimentación y Desarrollo, Coordinación Regional Culiacán, 80110, Culiacán, Sinaloa, Mexico
| | - Juan Manuel Tovar-Pedraza
- Laboratorio de Fitopatología, Centro de Investigación en Alimentación y Desarrollo, Coordinación Regional Culiacán, 80110, Culiacán, Sinaloa, Mexico.
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2
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Poudel RS, Belay K, Nelson B, Brueggeman R, Underwood W. Population and genome-wide association studies of Sclerotinia sclerotiorum isolates collected from diverse host plants throughout the United States. Front Microbiol 2023; 14:1251003. [PMID: 37829452 PMCID: PMC10566370 DOI: 10.3389/fmicb.2023.1251003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/29/2023] [Indexed: 10/14/2023] Open
Abstract
Introduction Sclerotinia sclerotiorum is a necrotrophic fungal pathogen causing disease and economic loss on numerous crop plants. This fungus has a broad host range and can infect over 400 plant species, including important oilseed crops such as soybean, canola, and sunflower. S. sclerotiorum isolates vary in aggressiveness of lesion formation on plant tissues. However, the genetic basis for this variation remains to be determined. The aims of this study were to evaluate a diverse collection of S. sclerotiorum isolates collected from numerous hosts and U.S. states for aggressiveness of stem lesion formation on sunflower, to evaluate the population characteristics, and to identify loci associated with isolate aggressiveness using genome-wide association mapping. Methods A total of 219 S. sclerotiorum isolates were evaluated for stem lesion formation on two sunflower inbred lines and genotyped using genotyping-by-sequencing. DNA markers were used to assess population differentiation across hosts, regions, and climatic conditions and to perform a genome-wide association study of isolate aggressiveness. Results and discussion We observed a broad range of aggressiveness for lesion formation on sunflower stems, and only a moderate correlation between aggressiveness on the two lines. Population genetic evaluations revealed differentiation between populations from warmer climate regions compared to cooler regions. Finally, a genome-wide association study of isolate aggressiveness identified three loci significantly associated with aggressiveness on sunflower. Functional characterization of candidate genes at these loci will likely improve our understanding of the virulence strategies used by this pathogen to cause disease on a wide array of agriculturally important host plants.
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Affiliation(s)
- Roshan Sharma Poudel
- Department of Plant Pathology, North Dakota State University, Fargo, ND, United States
| | - Kassaye Belay
- Department of Plant Pathology, North Dakota State University, Fargo, ND, United States
| | - Berlin Nelson
- Department of Plant Pathology, North Dakota State University, Fargo, ND, United States
| | - Robert Brueggeman
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA, United States
| | - William Underwood
- Edward T. Schafer Agricultural Research Center, Sunflower and Plant Biology Research Unit, USDA Agricultural Research Service, Fargo, ND, United States
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3
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Nieto-Lopez EH, Miorini TJJ, Wulkop-Gil CA, I Chilvers M, Giesler LJ, Jackson-Ziems TA, Kabbage M, Mueller DS, Smith DL, Tovar-Pedraza JM, Willbur JF, Everhart SE. Fungicide Sensitivity of Sclerotinia sclerotiorum from U.S. Soybean and Dry Bean, Compared to Different Regions and Climates. PLANT DISEASE 2023; 107:2395-2406. [PMID: 36691269 DOI: 10.1094/pdis-07-22-1707-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: 06/17/2023]
Abstract
Fungicide use is integral to reduce yield loss from Sclerotinia sclerotiorum on dry bean and soybean. Increasing fungicide use against this fungus may lead to resistance to the most common fungicides. Resistance has been reported in Brazil (Glycine max) and China (Brassica napus subsp. napus), however, few studies have investigated fungicide sensitivity of S. sclerotiorum in the United States. This work was conducted to determine if there was a difference in fungicide sensitivity of S. sclerotiorum isolates in the United States from: (i) dry bean versus soybean and (ii) fields with different frequencies of fungicide application. We further hypothesized that isolates with fungicide applications of a single active ingredient from tropical Brazil and subtropical Mexico were less sensitive than temperate U.S. isolates due to different management practices and climates. The EC50(D) fungicide sensitivity of 512 S. sclerotiorum isolates from the United States (443), Brazil (36), and Mexico (33) was determined using a discriminatory concentration (DC) previously identified for tetraconazole (2.0 ppm; EC50(D) range of 0.197 to 2.27 ppm), boscalid (0.2; 0.042 to 0.222), picoxystrobin (0.01; 0.006 to 0.027), and thiophanate-methyl, which had a qualitative DC of 10 ppm. Among the 10 least sensitive isolates to boscalid and picoxystrobin, 2 presented mutations known to confer resistance in the SdhB (qualitative) and SdhC (quantitative) genes; however, no strong resistance was found. This study established novel DCs that can be used for further resistance monitoring and baseline sensitivity of S. sclerotiorum to tetraconazole worldwide plus baseline sensitivity to boscalid in the United States.
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Affiliation(s)
- Edgar H Nieto-Lopez
- Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583, U.S.A
| | | | - Cristian A Wulkop-Gil
- Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583, U.S.A
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA 92037, U.S.A
| | - Martin I Chilvers
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Loren J Giesler
- Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583, U.S.A
| | | | - Mehdi Kabbage
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, U.S.A
| | - Daren S Mueller
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, U.S.A
| | - Damon L Smith
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, U.S.A
| | - Juan Manuel Tovar-Pedraza
- Coordinación Regional Culiacán, Centro de Investigación en Alimentación y Desarrollo, Culiacán, Sinaloa 80110, Mexico
| | - Jaime F Willbur
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, U.S.A
| | - Sydney E Everhart
- Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583, U.S.A
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, CT 06269-4067, U.S.A
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Hossain MM, Sultana F, Li W, Tran LSP, Mostofa MG. Sclerotinia sclerotiorum (Lib.) de Bary: Insights into the Pathogenomic Features of a Global Pathogen. Cells 2023; 12:cells12071063. [PMID: 37048136 PMCID: PMC10093061 DOI: 10.3390/cells12071063] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/11/2023] [Accepted: 03/23/2023] [Indexed: 04/03/2023] Open
Abstract
Sclerotinia sclerotiorum (Lib.) de Bary is a broad host-range fungus that infects an inclusive array of plant species and afflicts significant yield losses globally. Despite being a notorious pathogen, it has an uncomplicated life cycle consisting of either basal infection from myceliogenically germinated sclerotia or aerial infection from ascospores of carpogenically germinated sclerotia. This fungus is unique among necrotrophic pathogens in that it inevitably colonizes aging tissues to initiate an infection, where a saprophytic stage follows the pathogenic phase. The release of cell wall-degrading enzymes, oxalic acid, and effector proteins are considered critical virulence factors necessary for the effective pathogenesis of S. sclerotiorum. Nevertheless, the molecular basis of S. sclerotiorum pathogenesis is still imprecise and remains a topic of continuing research. Previous comprehensive sequencing of the S. sclerotiorum genome has revealed new insights into its genome organization and provided a deeper comprehension of the sophisticated processes involved in its growth, development, and virulence. This review focuses on the genetic and genomic aspects of fungal biology and molecular pathogenicity to summarize current knowledge of the processes utilized by S. sclerotiorum to parasitize its hosts. Understanding the molecular mechanisms regulating the infection process of S. sclerotiorum will contribute to devising strategies for preventing infections caused by this destructive pathogen.
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Batista ICA, Heck DW, Santos A, Alves G, Ferro CG, Dita M, Haddad F, Michereff SJ, Correia KC, da Silva CFB, Mizubuti ESG. The Population of Fusarium oxysporum f. sp. cubense in Brazil Is Not Structured by Vegetative Compatibility Group or by Geographic Origin. PHYTOPATHOLOGY 2022; 112:2416-2425. [PMID: 35759310 DOI: 10.1094/phyto-02-22-0045-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
Fusarium wilt, caused by the soilborne fungus Fusarium oxysporum f. sp. cubense (Foc), is considered one of the most destructive diseases of bananas in Brazil. In this study, a collection of 194 monosporic isolates from several banana-producing regions located in different climatic zones along a south-to-north transect in Brazil was formed to assess the genetic structure of the population of Foc. The isolates underwent pathogenicity tests, PCR diagnosis for the detection of tropical race 4, and screening of SIX homolog genes that produce putative effector proteins. The vegetative compatibility group (VCG) of 119 isolates was determined by pairing against 17 internationally known VCG-tester strains. A group of 158 isolates was selected for simple sequence repeat (SSR) genotyping. There was moderate diversity of Foc in Brazil. Eight VCGs were identified: 0120, 0122, 0124, 0125, 0128, 01215, 01220, and 01222, of which 78% of isolates belong to a single VCG, whereas 22% of isolates are assigned to multiple VCGs, belonging to complexes of VCGs. The distribution of VCGs is uneven and independent of the banana genotype. The isolates of a VCG shared a similar profile of SIX homologs, but there was no association with geographic region. Four SSR loci were polymorphic, and, on average, 7.5 alleles were detected per locus. Thirty-five multilocus genotypes (MLGs) were identified. There was no association between VCG and MLGs, and no genetic structure of the population of Foc in Brazil was detected.
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Affiliation(s)
- Izabel C A Batista
- Departamento de Fitopatologia, Universidade Federal de Viçosa, MG 36570-900, Brazil
| | - Daniel W Heck
- Departamento de Fitopatologia, Universidade Federal de Viçosa, MG 36570-900, Brazil
| | - Alessandro Santos
- Departamento de Fitopatologia, Universidade Federal de Viçosa, MG 36570-900, Brazil
| | - Gabriel Alves
- Departamento de Fitopatologia, Universidade Federal de Viçosa, MG 36570-900, Brazil
| | - Camila G Ferro
- Departamento de Fitopatologia, Universidade Federal de Viçosa, MG 36570-900, Brazil
| | - Miguel Dita
- Alliance of Bioversity International and CIAT, Cali, Colombia
| | | | | | | | | | - Eduardo S G Mizubuti
- Departamento de Fitopatologia, Universidade Federal de Viçosa, MG 36570-900, Brazil
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Taboada G, Abán CL, Mercado Cárdenas G, Spedaletti Y, Aparicio González M, Maita E, Ortega-Baes P, Galván M. Characterization of fungal pathogens and germplasm screening for disease resistance in the main production area of the common bean in Argentina. FRONTIERS IN PLANT SCIENCE 2022; 13:986247. [PMID: 36161011 PMCID: PMC9490223 DOI: 10.3389/fpls.2022.986247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/04/2022] [Indexed: 06/16/2023]
Abstract
The common bean (Phaseolus vulgaris L.) is the most important grain legume in the human diet, mainly in Africa and Latin America. Argentina is one of the five major producers of the common bean in the world, and the main cultivation areas are concentrated in the northwestern provinces of this country. Crop production of the common bean is often affected by biotic factors like some endemic fungal diseases, which exert a major economic impact on the region. The most important fungal diseases affecting the common bean in Argentina are white mold caused by Sclerotinia sclerotiorum, angular leaf spot caused by Pseudocercospora griseola, web blight and root rot caused by Rhizoctonia solani, which can cause production losses of up to 100% in the region. At the present, the most effective strategy for controlling these diseases is the use of genetic resistance. In this sense, population study and characterization of fungal pathogens are essential for developing cultivars with durable resistance. In this review we report diversity studies carried out on these three fungal pathogens affecting the common bean in northwestern Argentina, analyzing more than 200 isolates by means of molecular, morphological and pathogenic approaches. Also, the screening of physiological resistance in several common bean commercial lines and wild native germplasm is reviewed. This review contributes to the development of sustainable management strategies and cultural practices in bean production aimed to minimize yield losses due to fungal diseases in the common bean.
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Affiliation(s)
- Gisel Taboada
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT-Salta, Salta, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA) EEA Salta, Salta, Argentina
| | - Carla L. Abán
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT-Salta, Salta, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA) EEA Salta, Salta, Argentina
| | | | - Yamila Spedaletti
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT-Salta, Salta, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA) EEA Salta, Salta, Argentina
| | - Mónica Aparicio González
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT-Salta, Salta, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA) EEA Salta, Salta, Argentina
| | - Efrain Maita
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT-Salta, Salta, Argentina
- Laboratorio de Investigaciones Botánicas (LABIBO), Facultad de Ciencias Naturales, Universidad Nacional de Salta, Salta, Argentina
| | - Pablo Ortega-Baes
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT-Salta, Salta, Argentina
- Laboratorio de Investigaciones Botánicas (LABIBO), Facultad de Ciencias Naturales, Universidad Nacional de Salta, Salta, Argentina
| | - Marta Galván
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT-Salta, Salta, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA) EEA Salta, Salta, Argentina
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Derbyshire MC, Newman TE, Khentry Y, Owolabi Taiwo A. The evolutionary and molecular features of the broad-host-range plant pathogen Sclerotinia sclerotiorum. MOLECULAR PLANT PATHOLOGY 2022; 23:1075-1090. [PMID: 35411696 PMCID: PMC9276942 DOI: 10.1111/mpp.13221] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/09/2022] [Accepted: 03/25/2022] [Indexed: 05/21/2023]
Abstract
Sclerotinia sclerotiorum is a pathogenic fungus that infects hundreds of plant species, including many of the world's most important crops. Key features of S. sclerotiorum include its extraordinary host range, preference for dicotyledonous plants, relatively slow evolution, and production of protein effectors that are active in multiple host species. Plant resistance to this pathogen is highly complex, typically involving numerous polymorphisms with infinitesimally small effects, which makes resistance breeding a major challenge. Due to its economic significance, S. sclerotiorum has been subjected to a large amount of molecular and evolutionary research. In this updated pathogen profile, we review the evolutionary and molecular features of S. sclerotiorum and discuss avenues for future research into this important species.
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Affiliation(s)
- Mark C. Derbyshire
- Centre for Crop and Disease ManagementSchool of Molecular and Life SciencesCurtin UniversityPerthWestern AustraliaAustralia
| | - Toby E. Newman
- Centre for Crop and Disease ManagementSchool of Molecular and Life SciencesCurtin UniversityPerthWestern AustraliaAustralia
| | - Yuphin Khentry
- Centre for Crop and Disease ManagementSchool of Molecular and Life SciencesCurtin UniversityPerthWestern AustraliaAustralia
| | - Akeem Owolabi Taiwo
- Centre for Crop and Disease ManagementSchool of Molecular and Life SciencesCurtin UniversityPerthWestern AustraliaAustralia
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Genetic structure of Sclerotinia sclerotiorum populations from sunflower and cabbage in West Azarbaijan province of Iran. Sci Rep 2022; 12:9263. [PMID: 35662267 PMCID: PMC9166751 DOI: 10.1038/s41598-022-13350-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 05/11/2022] [Indexed: 11/08/2022] Open
Abstract
Sclerotinia sclerotiorum is one of the most destructive fungal pathogens infecting a wide array of plant species worldwide. Management of this pathogen relies on the coordinated use of fungicides and resistant host cultivars with other control measures, but the effectiveness of these methods requires knowledge of the genetic variability and structure of the fungal populations. To provide insight into the genetic diversity and structure of this pathogen in West Azarbaijan province of Iran, a total of 136 isolates were collected from symptomatic sunflower and cabbage plants within fields in three regions and analysed using inter-simple sequence repeat (ISSR) markers and intergenic spacer (IGS) region of the rRNA gene sequences. A total of 83 ISSR multilocus genotypes (MLGs) were identified, some of which were shared among at least two regional or host populations but in a low frequency. High genotypic diversity, low levels of clonal fraction, and random association of ISSR loci in a region indicated a low level of clonal reproduction, and possibly a high level of sexually recombining life cycle for the pathogen in the province. Marker analyses revealed that the pathogen was spatially homogeneous among fields, and thus similar control measures, such as the choice of resistant cultivars and fungicides, may effectively manage S. sclerotiorum within the region. Four IGS haplotypes (IGS1-IGS4) were detected within populations with IGS3 being the most prevalent haplotype. The low IGS haplotype diversity, the absence of spatial structure, and shared MLGs among populations may suggest a single introduction and subsequent dispersal of S. sclerotiorum within West Azarbaijan province.
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da Silva Lehner M, Alves KS, Del Ponte EM, Pethybridge SJ. Comparing the Fungicide Sensitivity of Sclerotinia sclerotiorum Using Mycelial Growth and Ascospore Germination Assays. PLANT DISEASE 2022; 106:360-363. [PMID: 34524868 DOI: 10.1094/pdis-06-21-1234-sc] [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: 06/13/2023]
Abstract
The infection of the floral tissues of snap bean and other crops by Sclerotinia sclerotiorum, the causative agent of white mold, is by ascospores. Irrespective of the fungicide mode of action being evaluated, in vitro fungicide sensitivity tests are conducted almost exclusively using mycelial growth assays. This is likely because of difficulties and time involved in sclerotial conditioning required to produce apothecia and ascospores. The objective of this research was to compare estimates of fungicide sensitivity between mycelial growth and ascospore germination assays for S. sclerotiorum. Sensitivity assays were conducted using serial doses of three fungicides commonly used to control white mold: boscalid, fluazinam, and thiophanate-methyl. A total of 27 isolates were evaluated in replicated trials conducted for each fungicide and assay type. The effective concentration to reduce mycelial growth or ascospore germination by 50% (EC50) was estimated for each isolate, fungicide, and assay type. The median EC50 values obtained from ascospore germination assays were 52.7, 10.0, and 2.7 times higher than those estimated from the mycelial growth for boscalid, fluazinam, and thiophanate-methyl, respectively. No significant correlation was found between EC50 values estimated by the two methods. These findings highlight differences that may be important in evaluating the sensitivity of S. sclerotiorum given the fungicide mode of action and how they will be used in the field.
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Affiliation(s)
- Miller da Silva Lehner
- Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| | - Kaique S Alves
- Departamento de Fitopatologia, Universidade Federal de Viçosa, 36570-900, Viçosa, MG, Brazil
| | - Emerson M Del Ponte
- Departamento de Fitopatologia, Universidade Federal de Viçosa, 36570-900, Viçosa, MG, Brazil
| | - Sarah J Pethybridge
- Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
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Silva RA, Ferro CG, Lehner MDS, Paula TJ, Mizubuti ESG. The Population of Sclerotinia sclerotiorum in Brazil Is Structured by Mycelial Compatibility Groups. PLANT DISEASE 2021; 105:3376-3384. [PMID: 33934631 DOI: 10.1094/pdis-01-21-0110-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: 06/12/2023]
Abstract
The genetic structure of the population of Sclerotinia sclerotiorum was analyzed using 238 individuals collected from different hosts. Individuals were characterized for microsatellite genotypes and mycelial compatibility groups (MCGs). A total of 22 MCGs and 64 multilocus lineages (MLLs) were identified. There was a close relationship between the MCGs and MLLs, but there was no association between MLLs and hosts or regions. At least 39 MCGs are present in Brazil, and 68.5% of the isolates were assigned to either MCG 1 or MCG 2. Eight new MCGs were found. Seven genetic groups were identified and associated with MCGs. Most genetic variation (70.0%) was because of differences among MCGs. High values of estimates of linkage disequilibrium among loci were more frequent in the total population (all MCGs). By contrast, there was evidence of random mating in subpopulations defined by MCGs 1 and 2. Additionally, there was evidence of outcrossing in the population of S. sclerotiorum in Brazil. The population was structured by MCGs; lineages originating from asexual reproduction or selfing prevail and are widely distributed in space, are persistent in time, and affect many hosts, but there is evidence of some degree of outcrossing, which may lead to a more genetically variable population in the future.
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Affiliation(s)
- Rhaphael A Silva
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Camila G Ferro
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Miller da S Lehner
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Trazilbo J Paula
- Empresa de Pesquisa Agropecuária de Minas Gerais, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Eduardo S G Mizubuti
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
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Mahalingam T, Chen W, Rajapakse CS, Somachandra KP, Attanayake RN. Genetic Diversity and Recombination in the Plant Pathogen Sclerotinia sclerotiorum Detected in Sri Lanka. Pathogens 2020; 9:E306. [PMID: 32331222 PMCID: PMC7238271 DOI: 10.3390/pathogens9040306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/14/2020] [Accepted: 04/17/2020] [Indexed: 01/20/2023] Open
Abstract
Sclerotinia sclerotiorum is an important fungal pathogen on many economically important crops including cabbage worldwide. Even though population structure and genetic diversity of S. sclerotiorum is well studied in temperate climatic conditions, only a few studies have been conducted in tropical countries. It is also not clear whether the populations are clonal or recombining in the tropics. In filling this information gap, 47 isolates of S. sclerotiorum were collected from commercial cabbage (Brassica oleracea L.) fields in Nuwara Eliya district of Sri Lanka, where the disease has been previously reported. All the isolates were subjected to genetic diversity study using mycelial compatibility grouping and microsatellite markers. Fourteen mycelial compatibility groups (MCGs) and 23 multilocus haplotypes (MLHs) were recorded. Mean expected heterozygosity of the population was 0.56. MLHs were weakly correlated with MCGs. Population genetic structure analysis and principal coordinates identified three genetic clusters. Genetic recombination was inferred within each genetic cluster when isolates were subjected to clone correction. There was evidence of multiple infections on single plant as detected by the presence of more than one MCG on each cabbage plant. However, multiple infections did not increase the disease severity in detached leaf assay. We found high genetic diversity and recombination of S. sclerotiorum population in a tropical country, Sri Lanka. Importance of detecting genetic structure when inferring recombination was also highlighted.
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Affiliation(s)
- Thirega Mahalingam
- Department of Plant and Molecular Biology, University of Kelaniya, Kelaniya 11600, Sri Lanka;
| | - Weidong Chen
- United States Department of Agriculture-Agriculture Research Service (USDA-ARS), Grain Legume Genetics and Physiology Research Unit, Washington State University, Pullman, WA 99164, USA;
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12
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Newman TE, Derbyshire MC. The Evolutionary and Molecular Features of Broad Host-Range Necrotrophy in Plant Pathogenic Fungi. FRONTIERS IN PLANT SCIENCE 2020; 11:591733. [PMID: 33304369 PMCID: PMC7693711 DOI: 10.3389/fpls.2020.591733] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/22/2020] [Indexed: 05/21/2023]
Abstract
Necrotrophic fungal pathogens cause considerable disease on numerous economically important crops. Some of these pathogens are specialized to one or a few closely related plant species, whereas others are pathogenic on many unrelated hosts. The evolutionary and molecular bases of broad host-range necrotrophy in plant pathogens are not very well-defined and form an on-going area of research. In this review, we discuss what is known about broad host-range necrotrophic pathogens and compare them with their narrow host-range counterparts. We discuss the evolutionary processes associated with host generalism, and highlight common molecular features of the broad host-range necrotrophic lifestyle, such as fine-tuning of host pH, modulation of host reactive oxygen species and metabolic degradation of diverse host antimicrobials. We conclude that broad host-range necrotrophic plant pathogens have evolved a range of diverse and sometimes convergent responses to a similar selective regime governed by interactions with a highly heterogeneous host landscape.
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Xia S, Xu Y, Hoy R, Zhang J, Qin L, Li X. The Notorious Soilborne Pathogenic Fungus Sclerotinia sclerotiorum: An Update on Genes Studied with Mutant Analysis. Pathogens 2019; 9:pathogens9010027. [PMID: 31892134 PMCID: PMC7168625 DOI: 10.3390/pathogens9010027] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/19/2019] [Accepted: 12/22/2019] [Indexed: 01/06/2023] Open
Abstract
Ascomycete Sclerotinia sclerotiorum (Lib.) de Bary is one of the most damaging soilborne fungal pathogens affecting hundreds of plant hosts, including many economically important crops. Its genomic sequence has been available for less than a decade, and it was recently updated with higher completion and better gene annotation. Here, we review key molecular findings on the unique biology and pathogenesis process of S. sclerotiorum, focusing on genes that have been studied in depth using mutant analysis. Analyses of these genes have revealed critical players in the basic biological processes of this unique pathogen, including mycelial growth, appressorium establishment, sclerotial formation, apothecial and ascospore development, and virulence. Additionally, the synthesis has uncovered gaps in the current knowledge regarding this fungus. We hope that this review will serve to build a better current understanding of the biology of this under-studied notorious soilborne pathogenic fungus.
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Affiliation(s)
- Shitou Xia
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China;
- Correspondence: (S.X.); (X.L.)
| | - Yan Xu
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (Y.X.); (R.H.)
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Ryan Hoy
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (Y.X.); (R.H.)
| | - Julia Zhang
- School of Kinesiology, University of British Columbia, Vancouver, BC V6T 1Z1, Canada;
| | - Lei Qin
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China;
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (Y.X.); (R.H.)
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Correspondence: (S.X.); (X.L.)
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Derbyshire MC, Denton-Giles M, Hane JK, Chang S, Mousavi-Derazmahalleh M, Raffaele S, Buchwaldt L, Kamphuis LG. A whole genome scan of SNP data suggests a lack of abundant hard selective sweeps in the genome of the broad host range plant pathogenic fungus Sclerotinia sclerotiorum. PLoS One 2019; 14:e0214201. [PMID: 30921376 PMCID: PMC6438532 DOI: 10.1371/journal.pone.0214201] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 03/10/2019] [Indexed: 01/08/2023] Open
Abstract
The pathogenic fungus Sclerotinia sclerotiorum infects over 600 species of plant. It is present in numerous environments throughout the world and causes significant damage to many agricultural crops. Fragmentation and lack of gene flow between populations may lead to population sub-structure. Within discrete recombining populations, positive selection may lead to a ‘selective sweep’. This is characterised by an increase in frequency of a favourable allele leading to reduction in genotypic diversity in a localised genomic region due to the phenomenon of genetic hitchhiking. We aimed to assess whether isolates of S. sclerotiorum from around the world formed genotypic clusters associated with geographical origin and to determine whether signatures of population-specific positive selection could be detected. To do this, we sequenced the genomes of 25 isolates of S. sclerotiorum collected from four different continents–Australia, Africa (north and south), Europe and North America (Canada and the northen United States) and conducted SNP based analyses of population structure and selective sweeps. Among the 25 isolates, there was evidence for two major population clusters. One of these consisted of 11 isolates from Canada, the USA and France (population 1), and the other consisted of nine isolates from Australia and one from Morocco (population 2). The rest of the isolates were genotypic outliers. We found that there was evidence of outcrossing in these two populations based on linkage disequilibrium decay. However, only a single candidate selective sweep was observed, and it was present in population 2. This sweep was close to a Major Facilitator Superfamily transporter gene, and we speculate that this gene may have a role in nutrient uptake from the host. The low abundance of selective sweeps in the S. sclerotiorum genome contrasts the numerous examples in the genomes of other fungal pathogens. This may be a result of its slow rate of evolution and low effective recombination rate due to self-fertilisation and vegetative reproduction.
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Affiliation(s)
- Mark Charles Derbyshire
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
- * E-mail:
| | - Matthew Denton-Giles
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
| | - James K. Hane
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
| | - Steven Chang
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
| | - Mahsa Mousavi-Derazmahalleh
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, Western Australia, Australia
| | - Sylvain Raffaele
- Laboratoire des Interactions Plantes-Micro-organismes (LIPM), Université de Toulouse, INRA, Toulouse, France
| | - Lone Buchwaldt
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatchewan, Saskatoon, Canada
| | - Lars G. Kamphuis
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
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Kamvar ZN, Amaradasa BS, Jhala R, McCoy S, Steadman JR, Everhart SE. Population structure and phenotypic variation of Sclerotinia sclerotiorum from dry bean ( Phaseolus vulgaris) in the United States. PeerJ 2017; 5:e4152. [PMID: 29230376 PMCID: PMC5723432 DOI: 10.7717/peerj.4152] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/20/2017] [Indexed: 02/03/2023] Open
Abstract
The ascomycete pathogen Sclerotinia sclerotiorum is a necrotrophic pathogen on over 400 known host plants, and is the causal agent of white mold on dry bean. Currently, there are no known cultivars of dry bean with complete resistance to white mold. For more than 20 years, bean breeders have been using white mold screening nurseries (wmn) with natural populations of S. sclerotiorum to screen new cultivars for resistance. It is thus important to know if the genetic diversity in populations of S. sclerotiorum within these nurseries (a) reflect the genetic diversity of the populations in the surrounding region and (b) are stable over time. Furthermore, previous studies have investigated the correlation between mycelial compatibility groups (MCG) and multilocus haplotypes (MLH), but none have formally tested these patterns. We genotyped 366 isolates of S. sclerotiorum from producer fields and wmn surveyed over 10 years in 2003-2012 representing 11 states in the United States of America, Australia, France, and Mexico at 11 microsatellite loci resulting in 165 MLHs. Populations were loosely structured over space and time based on analysis of molecular variance and discriminant analysis of principal components, but not by cultivar, aggressiveness, or field source. Of all the regions tested, only Mexico (n = 18) shared no MLHs with any other region. Using a bipartite network-based approach, we found no evidence that the MCGs accurately represent MLHs. Our study suggests that breeders should continue to test dry bean lines in several wmn across the United States to account for both the phenotypic and genotypic variation that exists across regions.
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Affiliation(s)
- Zhian N. Kamvar
- Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA
| | - B. Sajeewa Amaradasa
- Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA
- Current affiliation: Plant Pathology Department, University of Florida, Gainsville, FL, USA
| | - Rachana Jhala
- Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA
- Current affiliation: Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Serena McCoy
- Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA
| | - James R. Steadman
- Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA
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Vaghefi N, Kikkert JR, Bolton MD, Hanson LE, Secor GA, Nelson SC, Pethybridge SJ. Global genotype flow in Cercospora beticola populations confirmed through genotyping-by-sequencing. PLoS One 2017; 12:e0186488. [PMID: 29065114 PMCID: PMC5655429 DOI: 10.1371/journal.pone.0186488] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 10/01/2017] [Indexed: 11/18/2022] Open
Abstract
Genotyping-by-sequencing (GBS) was conducted on 333 Cercospora isolates collected from Beta vulgaris (sugar beet, table beet and swiss chard) in the USA and Europe. Cercospora beticola was confirmed as the species predominantly isolated from leaves with Cercospora leaf spot (CLS) symptoms. However, C. cf. flagellaris also was detected at a frequency of 3% in two table beet fields in New York. Resolution of the spatial structure and identification of clonal lineages in C. beticola populations using genome-wide single nucleotide polymorphisms (SNPs) obtained from GBS was compared to genotyping using microsatellites. Varying distance thresholds (bitwise distance = 0, 1.854599 × 10-4, and 1.298 × 10-3) were used for delineation of clonal lineages in C. beticola populations. Results supported previous reports of long distance dispersal of C. beticola through genotype flow. The GBS-SNP data set provided higher resolution in discriminating clonal lineages; however, genotype identification was impacted by filtering parameters and the distance threshold at which the multi-locus genotypes (MLGs) were contracted to multi-locus lineages. The type of marker or different filtering strategies did not impact estimates of population differentiation and structure. Results emphasize the importance of robust filtering strategies and designation of distance thresholds for delineating clonal lineages in population genomics analyses that depend on individual assignment and identification of clonal lineages. Detection of recurrent clonal lineages shared between the USA and Europe, even in the relaxed-filtered SNP data set and with a conservative distance threshold for contraction of MLGs, provided strong evidence for global genotype flow in C. beticola populations. The implications of intercontinental migration in C. beticola populations for CLS management are discussed.
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Affiliation(s)
- Niloofar Vaghefi
- School of Integrative Plant Science, Plant Pathology & Plant-Microbe Biology Section, Cornell University, Geneva, New York, United States of America
| | - Julie R. Kikkert
- Cornell Cooperative Extension, Canandaigua, New York, United States of America
| | - Melvin D. Bolton
- United States Department of Agriculture–Agricultural Research Service (USDA-ARS), Red River Valley Agricultural Research Center, Fargo, North Dakota, United States of America
- Department of Plant Pathology, North Dakota State University, Fargo, North Dakota, United States of America
| | - Linda E. Hanson
- USDA-ARS, Sugar Beet and Bean Research Unit, Michigan State University, Michigan, United States of America
| | - Gary A. Secor
- Department of Plant Pathology, North Dakota State University, Fargo, North Dakota, United States of America
| | - Scot C. Nelson
- College of Tropical Agriculture and Human Resources, Department of Tropical Plant and Soil Sciences, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Sarah J. Pethybridge
- School of Integrative Plant Science, Plant Pathology & Plant-Microbe Biology Section, Cornell University, Geneva, New York, United States of America
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