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de Souza TD, de Godoy SM, Feliciano DC, Binneck E, Rangel DEN, Sosa-Gómez DR. Genetic diversity of the entomopathogenic fungus Metarhizium rileyi based on de novo microsatellite markers. J Invertebr Pathol 2024; 204:108081. [PMID: 38458349 DOI: 10.1016/j.jip.2024.108081] [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: 10/24/2023] [Revised: 01/31/2024] [Accepted: 02/27/2024] [Indexed: 03/10/2024]
Abstract
Epizootics of the entomopathogenic fungus Metarhizium rileyi regulate lepidopteran populations in soybean, cotton, and peanut agroecosystems to the point that insecticide applications could be unnecessary. However, the contribution and how different strains operate during the epizootic are unknown. Several unanswered questions remain: 1. How many genotypes of M. rileyi are present during an epizootic? 2. Which genotype is the most common among them? 3. Are the genotypes involved in annual epizootics at the same location the same? Therefore, the development of molecular markers to accurately identify these genotypes is very important to answer these questions. SSR primers were designed by prospecting in silico to discriminate genotypes and infer the genetic diversity of M. rileyi isolates from the collection kept at Embrapa Soybean. We tested 13 SSR markers on 136 isolates to identify 43 clones and 12 different genetic clusters, with genetic diversity ranging from Hs = 0.15 (cluster I) to Hs = 0.41 (cluster IV) and an average diversity of 0.24. No clusters were categorically distinguished based on hosts or geographical origin using Bayesian clustering analysis. Nonetheless, some clusters comprised most of the isolates with a common geographic origin; for example, cluster VIII was mainly composed of isolates from Central-western Brazil, cluster II from Southern Brazil, and cluster XII from Quincy, Northern Florida, in the United States. Underrepresented regions (few isolates) from Pacific Island nations of Japan, the Philippines, and Indonesia (specifically from Java) were placed into clusters IX and X. Although the analyzed isolates displayed evidence of clonal structure, the genetic diversity indices suggest a potential for the species to adapt to different environmental conditions.
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Affiliation(s)
- Tamires Doroteo de Souza
- Department of Zoology, Biological Science Sector, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | | | - Daniele C Feliciano
- Department of General Biology, Universidade Estadual de Londrina, Londrina, PR, Brazil
| | | | - Drauzio E N Rangel
- Universidade Tecnológica Federal do Paraná, 85660-000, Dois Vizinhos, PR, Brazil
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Fu M, Qu Z, Pierre-Pierre N, Jiang D, Souza FL, Miklas PN, Porter LD, Vandemark GJ, Chen W. Exploring the Mycovirus Sclerotinia sclerotiorum Hypovirulence-Associated DNA Virus 1 as a Biocontrol Agent of White Mold Caused by Sclerotinia sclerotiorum. PLANT DISEASE 2024; 108:624-634. [PMID: 37743591 DOI: 10.1094/pdis-07-23-1458-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: 09/26/2023]
Abstract
Sclerotinia sclerotiorum is a necrotrophic fungal pathogen causing white mold on many important economic crops. Recently, some mycoviruses such as S. sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1) converted S. sclerotiorum into a beneficial symbiont that helps plants manage pathogens and other stresses. To explore the potential use of SsHADV-1 as a biocontrol agent in the United States and to test the efficacy of SsHADV-1-infected United States isolates in managing white mold and other crop diseases, SsHADV-1 was transferred from the Chinese strain DT-8 to United States isolates of S. sclerotiorum. SsHADV-1 is readily transmitted horizontally among United States isolates of S. sclerotiorum and consistently conferred hypovirulence to its host strains. Biopriming of dry bean seeds with hypovirulent S. sclerotiorum strains enhanced resistance to white mold, gray mold, and Rhizoctonia root rot. To investigate the underlying mechanisms, endophytic growth of hypovirulent S. sclerotiorum in dry beans was confirmed using PCR, and the expression of 12 plant defense-related genes were monitored before and after infection. The results indicated that the endophytic growth of SsHADV-1-infected strains in plants stimulated the expression of plant immunity pathway genes that assisted a rapid response from the plant to fungal infection. Finally, application of the seed biopriming technology with SsHADV-1-infected hypervirulent strain has promise for the biological control of several diseases of wheat, pea, and sunflower.
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Affiliation(s)
- Min Fu
- Department of Plant Pathology, Washington State University, Pullman, WA 99164, U.S.A
- Key Laboratory of Integrated Crop Pest Management of Anhui Province, College of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Zheng Qu
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Nickisha Pierre-Pierre
- Department of Plant Pathology, Washington State University, Pullman, WA 99164, U.S.A
- Grain Legume Genetics and Physiology Research Unit, USDA-ARS, Pullman, WA 99164, U.S.A
| | - Daohong Jiang
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Fernanda L Souza
- Grain Legume Genetics and Physiology Research Unit, USDA-ARS, Prosser, WA 99350, U.S.A
| | - Phillip N Miklas
- Grain Legume Genetics and Physiology Research Unit, USDA-ARS, Prosser, WA 99350, U.S.A
| | - Lyndon D Porter
- Grain Legume Genetics and Physiology Research Unit, USDA-ARS, Prosser, WA 99350, U.S.A
| | - George J Vandemark
- Grain Legume Genetics and Physiology Research Unit, USDA-ARS, Pullman, WA 99164, U.S.A
| | - Weidong Chen
- Grain Legume Genetics and Physiology Research Unit, USDA-ARS, Pullman, WA 99164, U.S.A
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James TY. Sex Without Sexes: Can the Cost of Finding a Mate Explain Diversity in Fungal Mating Systems? Integr Comp Biol 2023; 63:922-935. [PMID: 37218718 DOI: 10.1093/icb/icad037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/14/2023] [Accepted: 05/17/2023] [Indexed: 05/24/2023] Open
Abstract
Eukaryotes have evolved myriad ways of uniting gametes during sexual reproduction. A repeated pattern is the convergent evolution of a mating system with the fusion of larger gametes with smaller gametes (anisogamy) from that of fusion between morphologically identical gametes (isogamy). In anisogamous species, sexes are defined as individuals that produce only one gamete type. Although sexes abound throughout Eukarya, in fungi there are no biological sexes, because even in anisogamous species, individuals are hermaphroditic and produce both gamete types. For this reason, the term mating types is preferred over sexes, and, thus defined, only individuals of differing mating types can mate (homoallelic incompatibility). In anisogamous fungal species, there is scant evidence that there are more than two mating types, and this may be linked to genetic constraints, such as the use of mating types to determine the inheritance of cytoplasmic genomes. However, the mushroom fungi (Agaricomycetes) stand out as having both large numbers of mating types within a species, which will allow nearly all individuals to be compatible with each other, and reciprocal exchange of nuclei during mating, which will avoid cytoplasmic mixing and cyto-nuclear conflicts. Although the limitation of mating types to two in most fungi is consistent with the cyto-nuclear conflicts model, there are many facets of the Agaricomycete life cycle that also suggest they will demand a high outbreeding efficiency. Specifically, they are mostly obligately sexual and outcrossing, inhabit complex competitive niches, and display broadcast spore dispersal. Subsequently, the Agaricomycete individual pays a high cost to being choosy when encountering a mate. Here, I discuss the costs of mate finding and choice and demonstrate how most fungi have multiple ways of reducing these costs, which can explain why mating types are mostly limited to two per species. Nevertheless, it is perplexing that fungi have not evolved multiple mating types on more occasions nor evolved sexes. The few exceptions to these rules suggest that it is dictated by both molecular and evolutionary constraints.
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Affiliation(s)
- Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
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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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van der Merwe NA, Phakalatsane T, Wilken PM. The Unique Homothallic Mating-Type Loci of the Fungal Tree Pathogens Chrysoporthe syzygiicola and Chrysoporthe zambiensis from Africa. Genes (Basel) 2023; 14:1158. [PMID: 37372338 DOI: 10.3390/genes14061158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Chrysoporthe syzygiicola and C. zambiensis are ascomycete tree pathogens first described from Zambia, causing stem canker on Syzygium guineense and Eucalyptus grandis, respectively. The taxonomic descriptions of these two species were based on their anamorphic states, as no sexual states are known. The main purpose of this work was to use whole genome sequences to identify and define the mating-type (MAT1) loci of these two species. The unique MAT1 loci for C. zambiensis and C. syzygiicola consist of the MAT1-1-1, MAT1-1-2, and MAT1-2-1 genes, but the MAT1-1-3 gene is absent. Genes canonically associated with opposite mating types were present at the single mating-type locus, suggesting that C. zambiensis and C. syzygiicola have homothallic mating systems.
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Affiliation(s)
- Nicolaas A van der Merwe
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0028, South Africa
| | - Tshiamo Phakalatsane
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0028, South Africa
| | - P Markus Wilken
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0028, South Africa
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Bock CH, Frusso E, Zoppolo R, Ortiz ER, Shiller J, Charlton ND, Young CA, Randall JJ. Population Genetic Characteristics and Mating Type Frequency of Venturia effusa from Pecan in South America. PHYTOPATHOLOGY 2022; 112:2224-2235. [PMID: 35596236 DOI: 10.1094/phyto-01-22-0031-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: 06/15/2023]
Abstract
Scab, caused by the plant-pathogenic fungus Venturia effusa, is a major disease of pecan in South America, resulting in loss of quantity and quality of nut yield. Characteristics of the populations of V. effusa in South America are unknown. We used microsatellites to describe the genetic diversity and population structure of V. effusa in South America, and determined the mating type status of the pathogen. The four hierarchically sampled orchard populations from Argentina (AR), Brazil (BRC and BRS), and Uruguay (UR) had moderate to high genotypic and gene diversity. There was evidence of population differentiation (Fst = 0.196) but the correlation between geographic distance and genetic distance was not statistically significant. Genetic differentiation was minimal between the UR, BRC, and BRS populations, and these populations were more clearly differentiated from the AR population. The MAT1-1 and MAT1-2 mating types occurred in all four orchards and their frequencies did not deviate from the 1:1 ratio expected under random mating; however, multilocus linkage equilibrium was rejected in three of the four populations. The population genetics of South American populations of V. effusa has many similarities to the population genetics of V. effusa previously described in the United States. Characterizing the populations genetics and reproductive systems of V. effusa are important to establish the evolutionary potential of the pathogen and, thus, its adaptability-and can provide a basis for informed approaches to utilizing available host resistance and determining phytosanitary needs.
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Affiliation(s)
- Clive H Bock
- United States Department of Agriculture-Agriculture Research Service, Southeastern Fruit and Tree Nut Research Lab, 21 Dunbar Road, Byron, GA 31008, U.S.A
| | - Enrique Frusso
- Instituto de Recursos Biológicos, INTA Castelar, Las Cabañas y De Los Reseros s.n., (1686) Hurlingham, Buenos Aires, Argentina
| | - Roberto Zoppolo
- Instituto Nacional de Investigación Agropecuaria - INIA Las Brujas, Ruta 48 - km 10, El Colorado, Canelones, Uruguay, CP 90200
| | - Edson R Ortiz
- Divinut Indústria de Nozes Ltda., Rodovia BR-153, km 375, CEP 96504-800 - Cachoeira do Sul/RS, Brazil
| | | | - Nikki D Charlton
- Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK 73401, U.S.A
| | - Carolyn A Young
- Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK 73401, U.S.A
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, 74078, U.S.A
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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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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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López Hernández JF, Helston RM, Lange JJ, Billmyre RB, Schaffner SH, Eickbush MT, McCroskey S, Zanders SE. Diverse mating phenotypes impact the spread of wtf meiotic drivers in Schizosaccharomyces pombe. eLife 2021; 10:e70812. [PMID: 34895466 PMCID: PMC8789285 DOI: 10.7554/elife.70812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 12/10/2021] [Indexed: 11/13/2022] Open
Abstract
Meiotic drivers are genetic elements that break Mendel's law of segregation to be transmitted into more than half of the offspring produced by a heterozygote. The success of a driver relies on outcrossing (mating between individuals from distinct lineages) because drivers gain their advantage in heterozygotes. It is, therefore, curious that Schizosaccharomyces pombe, a species reported to rarely outcross, harbors many meiotic drivers. To address this paradox, we measured mating phenotypes in S. pombe natural isolates. We found that the propensity for cells from distinct clonal lineages to mate varies between natural isolates and can be affected both by cell density and by the available sexual partners. Additionally, we found that the observed levels of preferential mating between cells from the same clonal lineage can slow, but not prevent, the spread of a wtf meiotic driver in the absence of additional fitness costs linked to the driver. These analyses reveal parameters critical to understanding the evolution of S. pombe and help explain the success of meiotic drivers in this species.
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Affiliation(s)
| | | | - Jeffrey J Lange
- Stowers Institute for Medical ResearchKansas CityUnited States
| | | | - Samantha H Schaffner
- Stowers Institute for Medical ResearchKansas CityUnited States
- Kenyon CollegeGambierUnited States
| | | | - Scott McCroskey
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Sarah E Zanders
- Stowers Institute for Medical ResearchKansas CityUnited States
- Department of Molecular and Integrative Physiology, University of Kansas Medical CenterKansas CityUnited States
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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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Landscape Genetic Connectivity and Evidence for Recombination in the North American Population of the White-Nose Syndrome Pathogen, Pseudogymnoascus destructans. J Fungi (Basel) 2021; 7:jof7030182. [PMID: 33802538 PMCID: PMC8001231 DOI: 10.3390/jof7030182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 02/24/2021] [Accepted: 02/24/2021] [Indexed: 11/28/2022] Open
Abstract
White-Nose Syndrome is an ongoing fungal epizootic caused by epidermal infections of the fungus, Pseudogymnoascus destructans (P. destructans), affecting hibernating bat species in North America. Emerging early in 2006 in New York State, infections of P. destructans have spread to 38 US States and seven Canadian Provinces. Since then, clonal isolates of P. destructans have accumulated genotypic and phenotypic variations in North America. Using microsatellite and single nucleotide polymorphism markers, we investigated the population structure and genetic relationships among P. destructans isolates from diverse regions in North America to understand its pattern of spread, and to test hypotheses about factors that contribute to transmission. We found limited support for genetic isolation of P. destructans populations by geographic distance, and instead identified evidence for gene flow among geographic regions. Interestingly, allelic association tests revealed evidence for recombination in the North American P. destructans population. Our landscape genetic analyses revealed that the population structure of P. destructans in North America was significantly influenced by anthropogenic impacts on the landscape. Our results have important implications for understanding the mechanism(s) of P. destructans spread.
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Singh KP, Kumari P, Rai PK. Current Status of the Disease-Resistant Gene(s)/QTLs, and Strategies for Improvement in Brassica juncea. FRONTIERS IN PLANT SCIENCE 2021; 12:617405. [PMID: 33747001 PMCID: PMC7965955 DOI: 10.3389/fpls.2021.617405] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/08/2021] [Indexed: 05/15/2023]
Abstract
Brassica juncea is a major oilseed crop in tropical and subtropical countries, especially in south-east Asia like India, China, Bangladesh, and Pakistan. The widespread cultivation of genetically similar varieties tends to attract fungal pathogens which cause heavy yield losses in the absence of resistant sources. The conventional disease management techniques are often expensive, have limited efficacy, and cause additional harm to the environment. A substantial approach is to identify and use of resistance sources within the Brassica hosts and other non-hosts to ensure sustainable oilseed crop production. In the present review, we discuss six major fungal pathogens of B. juncea: Sclerotinia stem rot (Sclerotinia sclerotiorum), Alternaria blight (Alternaria brassicae), White rust (Albugo candida), Downy mildew (Hyaloperonospora parasitica), Powdery mildew (Erysiphe cruciferarum), and Blackleg (Leptoshaeria maculans). From discussing studies on pathogen prevalence in B. juncea, the review then focuses on highlighting the resistance sources and quantitative trait loci/gene identified so far from Brassicaceae and non-filial sources against these fungal pathogens. The problems in the identification of resistance sources for B. juncea concerning genome complexity in host subpopulation and pathotypes were addressed. Emphasis has been laid on more elaborate and coordinated research to identify and deploy R genes, robust techniques, and research materials. Examples of fully characterized genes conferring resistance have been discussed that can be transformed into B. juncea using advanced genomics tools. Lastly, effective strategies for B. juncea improvement through introgression of novel R genes, development of pre-breeding resistant lines, characterization of pathotypes, and defense-related secondary metabolites have been provided suggesting the plan for the development of resistant B. juncea.
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Affiliation(s)
- Kaushal Pratap Singh
- ICAR-Directorate of Rapeseed-Mustard Research, Bharatpur, India
- *Correspondence: Kaushal Pratap Singh,
| | - Preetesh Kumari
- Genetics Division, ICAR-Indian Agricultural Research Institute, New Delhi, India
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Michael PJ, Lui KY, Thomson LL, Stefanova K, Bennett SJ. Carpogenic Germinability of Diverse Sclerotinia sclerotiorum Populations Within the Southwestern Australian Grain Belt. PLANT DISEASE 2020; 104:2891-2897. [PMID: 32924875 DOI: 10.1094/pdis-12-19-2575-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Sclerotinia stem rot, caused by the necrotrophic plant pathogen Sclerotinia sclerotiorum (Lib.) de Bary, is a major disease of canola and pulses in Australia. Current disease management relies greatly on cultural and chemical means of control. Timing of fungicide applications remains a challenge, because efficacy is dependent on accurate prediction of ascospore release and presence on the plant. The aims of this study were to determine the optimal temperature for carpogenic germination of S. sclerotiorum populations sampled from canola and lupin fields in southwestern Australia and characterize diversity using mycelial compatibility groupings (MCGs). Sclerotia were collected from four diseased canola and one diseased lupin field from across southwestern Australia. Forty sclerotia from each population were incubated at four alternating temperatures of 30/15, 20/15, 20/4, and 15/4°C (12-h/12-h light/dark cycle) and assessed every 2 to 3 days for a 180-day period. MCG groupings for populations were characterized using 12 reference isolates. Results indicated the time to initial carpogenic germination decreased as diurnal temperature fluctuations decreased, with a fluctuation of 5°C (20/15°C) having the most rapid initial germination followed by 11°C (15/4°C) followed by 16°C (20/4°C). Optimal germination temperature for all five populations was 20/15°C; however, population responses to other diurnal temperature regimes varied considerably. No germination was observed at 30/15°C. MCG results indicate extensive diversity within and between populations, with at least 40% of sclerotia within each population unable to be characterized. We suggest that this diversity has enabled S. sclerotiorum populations to adapt to varying environmental conditions within southwestern Australia.
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Affiliation(s)
- Pippa J Michael
- Centre for Crop and Disease Management, Curtin University, Bentley, WA 6845, Australia
| | - King Yin Lui
- Centre for Crop and Disease Management, Curtin University, Bentley, WA 6845, Australia
| | - Linda L Thomson
- Centre for Crop and Disease Management, Curtin University, Bentley, WA 6845, Australia
| | | | - Sarita J Bennett
- Centre for Crop and Disease Management, Curtin University, Bentley, WA 6845, Australia
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Cheng Q, Frost KE, Dung JKS. Population Genetic Structure of Claviceps purpurea in Cool-Season Grass Seed Crops of Oregon. PHYTOPATHOLOGY 2020; 110:1773-1780. [PMID: 32573347 DOI: 10.1094/phyto-01-20-0005-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: 06/11/2023]
Abstract
Ergot, caused by Claviceps purpurea, is a primary disease concern in irrigated cool-season grass seed production systems of Oregon. In order to better understand the genetic diversity, population structure, and the epidemiology of C. purpurea in grasses grown for seed, 226 isolates were obtained using a hierarchical sampling strategy from two fields each of Kentucky bluegrass (n = 102) and perennial ryegrass (n = 124) and characterized using 12 microsatellite markers. A total of 194 unique multilocus genotypes (MLGs) were identified in this study. There were moderate levels of genotypic diversity (H = 3.43 to 4.23) and gene diversity (Hexp = 0.45 to 0.57) within fields. After clone correction, analysis of molecular variance revealed that 66% of the genetic variation occurred between the two C. purpurea isolates collected from the same seed head of individual plants, indicating that many of the seed heads bearing multiple sclerotia were infected by ascospores rather than conidia. However, the majority of the clonal isolates obtained in this study were collected from the same seed head (i.e., the two isolates were identical MLGs), indicating a role of conidia (honeydew) in secondary infections within seed heads. Genetic differentiation was observed between populations from different hosts (22%) but was confounded by geography. The standardized index of association ranged from 0.007 to 0.122 among the four populations, suggesting potential outcrossing and differences in the relative contribution of ascospores and conidia to ergot among the fields. The results from this study provide insights into the epidemiology of ergot in cool-season grass seed crops of Oregon.
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Affiliation(s)
- Qunkang Cheng
- Department of Botany and Plant Pathology, Central Oregon Agricultural Research Center, Oregon State University, Madras, OR
| | - Kenneth E Frost
- Department of Botany and Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston, OR
| | - Jeremiah K S Dung
- Department of Botany and Plant Pathology, Central Oregon Agricultural Research Center, Oregon State University, Madras, OR
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15
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Zhang C, Dong SS, Xu JY, He WM, Yang TL. PopLDdecay: a fast and effective tool for linkage disequilibrium decay analysis based on variant call format files. Bioinformatics 2020; 35:1786-1788. [PMID: 30321304 DOI: 10.1093/bioinformatics/bty875] [Citation(s) in RCA: 645] [Impact Index Per Article: 161.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/20/2018] [Accepted: 10/12/2018] [Indexed: 01/02/2023] Open
Abstract
MOTIVATION Linkage disequilibrium (LD) decay is of great interest in population genetic studies. However, no tool is available now to do LD decay analysis from variant call format (VCF) files directly. In addition, generation of pair-wise LD measurements for whole genome SNPs usually resulting in large storage wasting files. RESULTS We developed PopLDdecay, an open source software, for LD decay analysis from VCF files. It is fast and is able to handle large number of variants from sequencing data. It is also storage saving by avoiding exporting pair-wise results of LD measurements. Subgroup analyses are also supported. AVAILABILITY AND IMPLEMENTATION PopLDdecay is freely available at https://github.com/BGI-shenzhen/PopLDdecay.
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Affiliation(s)
- Chi Zhang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China.,BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | - Shan-Shan Dong
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | | | - Wei-Ming He
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China.,BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | - Tie-Lin Yang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
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16
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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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17
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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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18
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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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19
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Xu L, Li G, Jiang D, Chen W. Sclerotinia sclerotiorum: An Evaluation of Virulence Theories. ANNUAL REVIEW OF PHYTOPATHOLOGY 2018; 56:311-338. [PMID: 29958073 DOI: 10.1146/annurev-phyto-080417-050052] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Oxalic acid production in Sclerotinia sclerotiorum has long been associated with virulence. Research involving UV-induced, genetically undefined mutants that concomitantly lost oxalate accumulation, sclerotial formation, and pathogenicity supported the conclusion that oxalate is an essential pathogenicity determinant of S. sclerotiorum. However, recent investigations showed that genetically defined mutants that lost oxalic acid production but accumulated fumaric acid could cause disease on many plants and substantiated the conclusion that acidic pH, not oxalic acid per se, is the necessary condition for disease development. Critical evaluation of available evidence showed that the UV-induced mutants harbored previously unrecognized confounding genetic defects in saprophytic growth and pH responsiveness, warranting reevaluation of the conclusions about virulence based on the UV-induced mutants. Furthermore, analyses of the evidence suggested a hypothesis for the existence of an unrecognized regulator responsive to acidic pH. Identifying the unknown pH regulator would offer a new avenue for investigating pH sensing/regulation in S. sclerotiorum and novel targets for intervention in disease control strategies.
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Affiliation(s)
- Liangsheng Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, People's Republic of China
| | - Guoqing Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
| | - Daohong Jiang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
| | - Weidong Chen
- Grain Legume Genetics and Physiology Research Unit, US Department of Agriculture, Agricultural Research Service, Washington State University, Pullman, Washington 99164, USA
- Departments of Plant Pathology and Molecular Plant Sciences Program, Washington State University, Pullman, Washington 99164, USA;
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20
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Brasier C, King K, Kirisits T, Orton E, Webber J. High frequency of vegetative incompatibility combined with haploid selfing in the native European ash foliage coloniser Hymenoscyphus albidus. FUNGAL ECOL 2017. [DOI: 10.1016/j.funeco.2017.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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21
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Coelho MA, Bakkeren G, Sun S, Hood ME, Giraud T. Fungal Sex: The Basidiomycota. Microbiol Spectr 2017; 5:10.1128/microbiolspec.FUNK-0046-2016. [PMID: 28597825 PMCID: PMC5467461 DOI: 10.1128/microbiolspec.funk-0046-2016] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Indexed: 12/29/2022] Open
Abstract
Fungi of the Basidiomycota, representing major pathogen lineages and mushroom-forming species, exhibit diverse means to achieve sexual reproduction, with particularly varied mechanisms to determine compatibilities of haploid mating partners. For species that require mating between distinct genotypes, discrimination is usually based on both the reciprocal exchange of diffusible mating pheromones, rather than sexes, and the interactions of homeodomain protein signals after cell fusion. Both compatibility factors must be heterozygous in the product of mating, and genetic linkage relationships of the mating pheromone/receptor and homeodomain genes largely determine the complex patterns of mating-type variation. Independent segregation of the two compatibility factors can create four haploid mating genotypes from meiosis, referred to as tetrapolarity. This condition is thought to be ancestral to the basidiomycetes. Alternatively, cosegregation by linkage of the two mating factors, or in some cases the absence of the pheromone-based discrimination, yields only two mating types from meiosis, referred to as bipolarity. Several species are now known to have large and highly rearranged chromosomal regions linked to mating-type genes. At the population level, polymorphism of the mating-type genes is an exceptional aspect of some basidiomycete fungi, where selection under outcrossing for rare, intercompatible allelic variants is thought to be responsible for numbers of mating types that may reach several thousand. Advances in genome sequencing and assembly are yielding new insights by comparative approaches among and within basidiomycete species, with the promise to resolve the evolutionary origins and dynamics of mating compatibility genetics in this major eukaryotic lineage.
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Affiliation(s)
- Marco A. Coelho
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Guus Bakkeren
- Agriculture and Agri-Food Canada, Summerland Research and Development Centre Summerland, BC, V0H 1Z0, Canada
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael E. Hood
- Department of Biology, Amherst College, 01002-5000 Amherst, Massachusetts, USA
| | - Tatiana Giraud
- Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
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22
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Clarkson JP, Warmington RJ, Walley PG, Denton-Giles M, Barbetti MJ, Brodal G, Nordskog B. Population Structure of Sclerotinia subarctica and Sclerotinia sclerotiorum in England, Scotland and Norway. Front Microbiol 2017; 8:490. [PMID: 28421039 PMCID: PMC5378995 DOI: 10.3389/fmicb.2017.00490] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/09/2017] [Indexed: 01/01/2023] Open
Abstract
Sclerotinia species are important fungal pathogens of a wide range of crops and wild host plants. While the biology and population structure of Sclerotinia sclerotiorum has been well-studied, little information is available for the related species S. subarctica. In this study, Sclerotinia isolates were collected from different crop plants and the wild host Ranuculus ficaria (meadow buttercup) in England, Scotland, and Norway to determine the incidence of Sclerotinia subarctica and examine the population structure of this pathogen for the first time. Incidence was very low in England, comprising only 4.3% of isolates while moderate and high incidence of S. subarctica was identified in Scotland and Norway, comprising 18.3 and 48.0% of isolates respectively. Characterization with eight microsatellite markers identified 75 haplotypes within a total of 157 isolates over the three countries with a few haplotypes in Scotland and Norway sampled at a higher frequency than the rest across multiple locations and host plants. In total, eight microsatellite haplotypes were shared between Scotland and Norway while none were shared with England. Bayesian and principal component analyses revealed common ancestry and clustering of Scottish and Norwegian S. subarctica isolates while English isolates were assigned to a separate population cluster and exhibited low diversity indicative of isolation. Population structure was also examined for S. sclerotiorum isolates from England, Scotland, Norway, and Australia using microsatellite data, including some from a previous study in England. In total, 484 haplotypes were identified within 800 S. sclerotiorum isolates with just 15 shared between England and Scotland and none shared between any other countries. Bayesian and principal component analyses revealed a common ancestry and clustering of the English and Scottish isolates while Norwegian and Australian isolates were assigned to separate clusters. Furthermore, sequencing part of the intergenic spacer (IGS) region of the rRNA gene resulted in 26 IGS haplotypes within 870 S. sclerotiorum isolates, nine of which had not been previously identified and two of which were also widely distributed across different countries. S. subarctica therefore has a multiclonal population structure similar to S. sclerotiorum, but has a different ancestry and distribution across England, Scotland, and Norway.
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Affiliation(s)
- John P Clarkson
- Warwick Crop Centre, School of Life Sciences, University WarwickWarwick, UK
| | | | - Peter G Walley
- Warwick Crop Centre, School of Life Sciences, University WarwickWarwick, UK.,Institute of Integrative Biology, University of LiverpoolLiverpool, UK
| | | | - Martin J Barbetti
- Faculty of Science, School of Agriculture and Environment, University of Western AustraliaCrawley, WA, Australia
| | - Guro Brodal
- Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy ResearchÅs, Norway
| | - Berit Nordskog
- Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy ResearchÅs, Norway
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23
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Lehner MS, de Paula Júnior TJ, Del Ponte EM, Mizubuti ESG, Pethybridge SJ. Independently founded populations of Sclerotinia sclerotiorum from a tropical and a temperate region have similar genetic structure. PLoS One 2017; 12:e0173915. [PMID: 28296968 PMCID: PMC5352009 DOI: 10.1371/journal.pone.0173915] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/28/2017] [Indexed: 11/23/2022] Open
Abstract
Sclerotinia sclerotiorum populations from tropical agricultural zones have been suggested to be more variable compared to those from temperate zones. However, no data were available comparing populations from both zones using the same set of markers. In this study, we compared S. sclerotiorum populations from the United States of America (USA, temperate) and southeast Brazil (tropical) using the frequency of mycelial compatibility groups (MCGs) and 13 microsatellite (SSR) markers. Populations were sourced from diseased plants within leguminous crops in New York, USA (NY; n = 78 isolates), and Minas Gerais State, Brazil (MG; n = 109). Twenty MCGs were identified in NY and 14 were previously reported in MG. The effective number of genotypes based on Hill's number of order 0, which corresponded to the number of multilocus genotypes (MLGs) were 22 (95% CI = 15.6-28.4) and 24 (95% CI = 18.9-29.1) in NY and MG, respectively. Clonal fractions of MLGs were 71.8% (NY) and 78.0% (MG). The effective number of genotypes based on Hill's number of orders 1 and 2 in NY were 8.9 (95% CI = 5.2-12.6) and 4.4 (95% CI = 2.6-6.1), respectively. For MG these indices were 11.4 (95% CI = 8.7-14.1) and 7.1 (95% CI = 5.1-9.0), respectively. There were no significant differences of allelic richness, private allelic richness, gene diversity, effective number of alleles and genotype evenness between the NY and MG populations. The populations were differentiated, with 29% of total variance attributed to differences between them and G''ST and Jost's D indices higher than 0.50. Cluster analysis revealed dissimilarity higher than 80% among most MLGs from both populations. Different alleles segregated in the populations but both had similar levels of genotypic variability.
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Affiliation(s)
- Miller S. Lehner
- School of Integrative Plant Science, Plant Pathology & Plant-Microbe Biology Section, Cornell University, Geneva, New York, United States of America
| | | | - Emerson M. Del Ponte
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Eduardo S. G. Mizubuti
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - 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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24
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Yang D, Zhang J, Wu M, Chen W, Li G, Yang L. Characterization of the Mycelial Compatibility Groups and Mating Type Alleles in Populations of Sclerotinia minor in Central China. PLANT DISEASE 2016; 100:2313-2318. [PMID: 30682912 DOI: 10.1094/pdis-12-15-1453-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ninety-five single-sclerotium isolates were obtained from lettuce and weeds in three counties in central China. They were identified belonging to Sclerotinia minor based on colony morphology and the S. minor-specific DNA marker. Mycelial compatibility groups (MCGs) and the mating type (MAT) alleles in these isolates were determined using the methods of paired cultures and specific PCR, respectively, and the MCG data were used to calculate Shannon's H index (H) and Simpson index (S), thereby evaluating diversity of S. minor. Eight MCGs (MCG1 to MCG8) and two MAT alleles (Inv+, Inv-) were identified in these isolates. Low diversity was detected for the total 95 isolates (H = 1.748, S = 0.786). Isolates of different MCGs or with different MAT alleles did not significantly differ (P > 0.05) in mycelial growth rate on potato dextrose agar (PDA, 20°C) or lesion diameter on lettuce leaves (20°C), but slightly differed in the number of sclerotia produced on PDA (20°C). Furthermore, this study reported five new host plants of S. minor in China, including Capsella bursa-pastoris, Oenanthe javanica, Fragaria gracilis, Ranunculus ternatus, and Salvia plebeia, and identified three hypovirulent isolates. These results broaden our understanding about the population biology of S. minor.
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Affiliation(s)
- Dan Yang
- The State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jing Zhang
- The State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan 430070, China
| | - Mingde Wu
- The State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan 430070, China
| | - Weidong Chen
- United States Department of Agriculture, Agricultural Research Service, Washington State University, Pullman, WA
| | - Guoqing Li
- The State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan 430070, China
| | - Long Yang
- The State Key Laboratory of Agricultural Microbiology and Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan 430070, China
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Li HX, Brewer MT. Spatial Genetic Structure and Population Dynamics of Gummy Stem Blight Fungi Within and Among Watermelon Fields in the Southeastern United States. PHYTOPATHOLOGY 2016; 106:900-908. [PMID: 27050575 DOI: 10.1094/phyto-01-16-0006-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The epidemiology of gummy stem blight (GSB) of cucurbits, particularly the sources of inoculum for epidemics, and the regional population genetic structure of the causal fungi Stagonosporopsis cucurbitacearum (syn. Didymella bryoniae), S. citrulli, and S. caricae are not well understood. Our goal was to better understand the population structure and fine-scale spatial genetic structure of Stagonosporopsis spp. in the southeastern United States. Overall, 528 isolates collected from nine fields in 2012, 2013, and 2014 were genotyped with 16 microsatellite markers. In 2013, S. caricae was first detected in the southeastern United States; however, S. citrulli remained the dominant species, representing 96.4% of the isolates. Principal coordinates analysis, discriminant analysis of principle components, and analysis of molecular variance indicated that most populations of S. citrulli were genotypically diverse, yet dominated by widely distributed clones that contributed to regional population structure. Spatial genetic structure resulting from aggregation of clonal genotypes at distances of less than 10 meters was detected within two of three fields in which isolate location was recorded. Studies on the epidemiological and fitness differences between S. citrulli and S. caricae and of prevalent and widespread clones will provide insight into the population structure and species dynamics observed in GSB epidemics.
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Affiliation(s)
- Hao-Xi Li
- Department of Plant Pathology, University of Georgia, Athens, GA
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Genetic Dissection of Sexual Reproduction in a Primary Homothallic Basidiomycete. PLoS Genet 2016; 12:e1006110. [PMID: 27327578 PMCID: PMC4915694 DOI: 10.1371/journal.pgen.1006110] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 05/16/2016] [Indexed: 11/19/2022] Open
Abstract
In fungi belonging to the phylum Basidiomycota, sexual compatibility is usually determined by two genetically unlinked MAT loci, one of which encodes one or more pheromone receptors (P/R) and pheromone precursors, and the other comprehends at least one pair of divergently transcribed genes encoding homeodomain (HD) transcription factors. Most species are heterothallic, meaning that sexual reproduction requires mating between two sexually compatible individuals harboring different alleles at both MAT loci. However, some species are known to be homothallic, one individual being capable of completing the sexual cycle without mating with a genetically distinct partner. While the molecular underpinnings of the heterothallic life cycles of several basidiomycete model species have been dissected in great detail, much less is known concerning the molecular basis for homothallism. Following the discovery in available draft genomes of the homothallic basidiomycetous yeast Phaffia rhodozyma of P/R and HD genes, we employed available genetic tools to determine their role in sexual development. Two P/R clusters, each harboring one pheromone receptor and one pheromone precursor gene were found in close vicinity of each other and were shown to form two redundant P/R pairs, each receptor being activated by the pheromone encoded by the most distal pheromone precursor gene. The HD locus is apparently genetically unlinked to the P/R locus and encodes a single pair of divergently transcribed HD1 and HD2 transcription factors, both required for normal completion of the sexual cycle. Given the genetic makeup of P. rhodozyma MAT loci, we postulate that it is a primarily homothallic organism and we propose a model for the interplay of molecular interactions required for sexual development in this species. Phaffia rhodozyma is considered one of the most promising microbial source of the carotenoid astaxanthin. Further development of this yeast as an industrial organism will benefit from new insights regarding its sexual reproduction system. Some fungi are capable of sexual reproduction without the need for a sexually compatible partner, a behavior called homothallism. For some of these fungi, it was observed that they carried in a single individual all the genes normally determining sexual identity in two distinct sexually compatible individuals, but in most cases the role of these genes is still unclear. Here we examined in detail the homothallic sexual cycle of the yeast Phaffia rhodozyma that belongs to the Basidiomycota, which is the fungal lineage that also includes the mushrooms. Phaffia rhodozyma produces astaxanthin, a pigment with antioxidant properties used in the food and cosmetic industries and is accessible to genetic modifications, so far aimed mainly at improving astaxanthin production. Here we harnessed these genetic tools to dissect the self-fertile life cycle of this yeast and found that all genes normally involved in two-partner sexual reproduction are also required for self-fertile sex in P. rhodozyma and propose a model describing molecular interactions required to trigger sexual development. We also generated preferably outcrossing strains, which are potentially useful for further improvement of P. rhodozyma as an industrial organism.
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Xu L, Jardini TM, Chen W. Direct repeat-mediated DNA deletion of the mating type MAT1-2 genes results in unidirectional mating type switching in Sclerotinia trifoliorum. Sci Rep 2016; 6:27083. [PMID: 27255676 PMCID: PMC4891775 DOI: 10.1038/srep27083] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/13/2016] [Indexed: 11/18/2022] Open
Abstract
The necrotrophic fungal pathogen Sclerotinia trifoliorum exhibits ascospore dimorphism and unidirectional mating type switching - self-fertile strains derived from large ascospores produce both self-fertile (large-spores) and self-sterile (small-spores) offsprings in a 4:4 ratio. The present study, comparing DNA sequences at MAT locus of both self-fertile and self-sterile strains, found four mating type genes (MAT1-1-1, MAT1-1-5, MAT1-2-1 and MAT1-2-4) in the self-fertile strain. However, a 2891-bp region including the entire MAT1-2-1 and MAT1-2-4 genes had been completely deleted from the MAT locus in the self-sterile strain. Meanwhile, two copies of a 146-bp direct repeat motif flanking the deleted region were found in the self-fertile strain, but only one copy of this 146-bp motif (a part of the MAT1-1-1 gene) was present in the self-sterile strain. The two direct repeats were believed to be responsible for the deletion through homologous intra-molecular recombination in meiosis. Tetrad analyses showed that all small ascospore-derived strains lacked the missing DNA between the two direct repeats that was found in all large ascospore-derived strains. In addition, heterokaryons at the MAT locus were observed in field isolates as well as in laboratory derived isolates.
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MESH Headings
- Ascomycota/genetics
- Ascomycota/growth & development
- Ascomycota/metabolism
- Base Sequence
- DNA, Fungal/genetics
- DNA, Fungal/metabolism
- DNA, Intergenic/genetics
- DNA, Intergenic/metabolism
- Genes, Mating Type, Fungal
- Genetic Loci
- Genome, Fungal
- Homologous Recombination
- Meiosis
- Repetitive Sequences, Nucleic Acid
- Sequence Alignment
- Sequence Deletion
- Spores, Fungal/genetics
- Spores, Fungal/growth & development
- Spores, Fungal/metabolism
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Affiliation(s)
- Liangsheng Xu
- Department of Plant Pathology, Washington State University, Pullman, WA 99164, USA
| | - Teresa M. Jardini
- Department of Plant Pathology, Washington State University, Pullman, WA 99164, USA
| | - Weidong Chen
- Department of Plant Pathology, Washington State University, Pullman, WA 99164, USA
- USDA-ARS, Grain Legume Genetics and Physiology Research Unit, Washington State University, Pullman, WA 99164, USA
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Talas F, McDonald BA. Genome-wide analysis of Fusarium graminearum field populations reveals hotspots of recombination. BMC Genomics 2015; 16:996. [PMID: 26602546 PMCID: PMC4659151 DOI: 10.1186/s12864-015-2166-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 10/29/2015] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Fusarium graminearum (Fg) is a ubiquitous pathogen of wheat, barley and maize causing Fusarium head blight. Large annual yield losses and contamination of foodstuffs with harmful mycotoxins make Fg one of the most-studied plant pathogens. Analyses of natural field populations can lead to a better understanding of the evolutionary processes affecting this pathogen. Restriction site associated DNA sequencing (RADseq) was used to conduct population genomics analyses including 213 pathogen isolates from 13 German field populations of Fg. RESULTS High genetic diversity was found within Fg field populations and low differentiation (FST = 0.003) was found among populations. Linkage disequilibrium (LD) decayed rapidly over a distance of 1000 bp. The low multilocus LD indicates that significant sexual recombination occurs in all populations. Several recombination hotspots were detected on each chromosome, but different chromosomes showed different levels of recombination. There was some evidence for selection hotspots. CONCLUSIONS The population genomic structure of Fg is consistent with a high degree of sexual recombination that is not equally distributed across the chromosomes. The high gene flow found among these field populations should enable this pathogen to adapt rapidly to changes in its environment, including deployment of resistant cultivars, applications of fungicides and a warming climate.
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Affiliation(s)
- Firas Talas
- ETH Zurich, Institute of Integrative Biology, Zurich (IBZ), Plant Pathology, 8092, Zurich, Switzerland.
| | - Bruce A McDonald
- ETH Zurich, Institute of Integrative Biology, Zurich (IBZ), Plant Pathology, 8092, Zurich, Switzerland.
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Aldrich-Wolfe L, Travers S, Nelson BD. Genetic Variation of Sclerotinia sclerotiorum from Multiple Crops in the North Central United States. PLoS One 2015; 10:e0139188. [PMID: 26417989 PMCID: PMC4587960 DOI: 10.1371/journal.pone.0139188] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 09/10/2015] [Indexed: 11/19/2022] Open
Abstract
Sclerotinia sclerotiorum is an important pathogen of numerous crops in the North Central region of the United States. The objective of this study was to examine the genetic diversity of 145 isolates of the pathogen from multiple hosts in the region. Mycelial compatibility groups (MCG) and microsatellite haplotypes were determined and analyzed for standard estimates of population genetic diversity and the importance of host and distance for genetic variation was examined. MCG tests indicated there were 49 different MCGs in the population and 52 unique microsatellite haplotypes were identified. There was an association between MCG and haplotype such that isolates belonging to the same MCG either shared identical haplotypes or differed at no more than 2 of the 12 polymorphic loci. For the majority of isolates, there was a one-to-one correspondence between MCG and haplotype. Eleven MCGs shared haplotypes. A single haplotype was found to be prevalent throughout the region. The majority of genetic variation in the isolate collection was found within rather than among host crops, suggesting little genetic divergence of S. sclerotiorum among hosts. There was only weak evidence of isolation by distance. Pairwise population comparisons among isolates from canola, dry bean, soybean and sunflower suggested that gene flow between host-populations is more common for some crops than others. Analysis of linkage disequilibrium in the isolates from the four major crops indicated primarily clonal reproduction, but also evidence of genetic recombination for isolates from canola and sunflower. Accordingly, genetic diversity was highest for populations from canola and sunflower. Distribution of microsatellite haplotypes across the study region strongly suggest that specific haplotypes of S. sclerotiorum are often found on multiple crops, movement of individual haplotypes among crops is common and host identity is not a barrier to gene flow for S. sclerotiorum in the north central United States.
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Affiliation(s)
- Laura Aldrich-Wolfe
- Biology Department, Concordia College, Moorhead, Minnesota, United States of America
| | - Steven Travers
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Berlin D. Nelson
- Department of Plant Pathology, North Dakota State University, Fargo, North Dakota, United States of America
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Grognet P, Silar P. Maintaining heterokaryosis in pseudo-homothallic fungi. Commun Integr Biol 2015; 8:e994382. [PMID: 26479494 PMCID: PMC4594319 DOI: 10.4161/19420889.2014.994382] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 11/06/2014] [Indexed: 01/09/2023] Open
Abstract
Among all the strategies displayed by fungi to reproduce and propagate, some species have adopted a peculiar behavior called pseudo-homothallism. Pseudo-homothallic fungi are true heterothallics, i.e., they need 2 genetically-compatible partners to mate, but they produce self-fertile mycelium in which the 2 different nuclei carrying the compatible mating types are present. This lifestyle not only enables the fungus to reproduce without finding a compatible partner, but also to cross with any mate it may encounter. However, to be fully functional, pseudo-homothallism requires maintaining heterokaryosis at every stage of the life cycle. We recently showed that neither the structure of the mating-type locus nor hybrid-enhancing effect due to the presence of the 2 mating types accounts for the maintenance of heterokaryosis in the pseudo-homothallic fungus P. anserina. In this addendum, we summarize the mechanisms creating heterokaryosis in P. anserina and 2 other well-known pseudo-homothallic fungi, Neurospora tetrasperma and Agaricus bisporus. We also discuss mechanisms potentially involved in maintaining heterokaryosis in these 3 species.
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Affiliation(s)
- Pierre Grognet
- Univ Paris Diderot; Sorbonne Paris Cité; Institut des Energies de Demain ; Paris, France
| | - Philippe Silar
- Univ Paris Diderot; Sorbonne Paris Cité; Institut des Energies de Demain ; Paris, France
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Johnson DA, Atallah ZK. Disease Cycle, Development and Management of Sclerotinia Stem Rot of Potato. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/ajps.2014.525388] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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