1
|
Attah V, Milner DS, Fang Y, Yan X, Leonard G, Heitman J, Talbot NJ, Richards TA. Duplication and neofunctionalization of a horizontally transferred xyloglucanase as a facet of the Red Queen coevolutionary dynamic. Proc Natl Acad Sci U S A 2024; 121:e2218927121. [PMID: 38830094 PMCID: PMC11181080 DOI: 10.1073/pnas.2218927121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 04/20/2024] [Indexed: 06/05/2024] Open
Abstract
Oomycete protists share phenotypic similarities with fungi, including the ability to cause plant diseases, but branch in a distant region of the tree of life. It has been suggested that multiple horizontal gene transfers (HGTs) from fungi-to-oomycetes contributed to the evolution of plant-pathogenic traits. These HGTs are predicted to include secreted proteins that degrade plant cell walls, a barrier to pathogen invasion and a rich source of carbohydrates. Using a combination of phylogenomics and functional assays, we investigate the diversification of a horizontally transferred xyloglucanase gene family in the model oomycete species Phytophthora sojae. Our analyses detect 11 xyloglucanase paralogs retained in P. sojae. Using heterologous expression in yeast, we show consistent evidence that eight of these paralogs have xyloglucanase function, including variants with distinct protein characteristics, such as a long-disordered C-terminal extension that can increase xyloglucanase activity. The functional variants analyzed subtend a phylogenetic node close to the fungi-to-oomycete transfer, suggesting the horizontally transferred gene was a bona fide xyloglucanase. Expression of three xyloglucanase paralogs in Nicotiana benthamiana triggers high-reactive oxygen species (ROS) generation, while others inhibit ROS responses to bacterial immunogens, demonstrating that the paralogs differentially stimulate pattern-triggered immunity. Mass spectrometry of detectable enzymatic products demonstrates that some paralogs catalyze the production of variant breakdown profiles, suggesting that secretion of variant xyloglucanases increases efficiency of xyloglucan breakdown as well as diversifying the damage-associated molecular patterns released. We suggest that this pattern of neofunctionalization and the variant host responses represent an aspect of the Red Queen host-pathogen coevolutionary dynamic.
Collapse
Affiliation(s)
- Victoria Attah
- Department of Biology, University of Oxford, OxfordOX1 3SZ, United Kingdom
| | - David S. Milner
- Department of Biology, University of Oxford, OxfordOX1 3SZ, United Kingdom
| | - Yufeng Fang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC27710
| | - Xia Yan
- The Sainsbury Laboratory, University of East Anglia, Norwich Research ParkNR4 7UH, United Kingdom
| | - Guy Leonard
- Department of Biology, University of Oxford, OxfordOX1 3SZ, United Kingdom
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC27710
| | - Nicholas J. Talbot
- The Sainsbury Laboratory, University of East Anglia, Norwich Research ParkNR4 7UH, United Kingdom
| | - Thomas A. Richards
- Department of Biology, University of Oxford, OxfordOX1 3SZ, United Kingdom
| |
Collapse
|
2
|
Jeon BS, Park MG. Morphology, phylogeny, and host range of the novel early-diverging oomycete Sirolpidium dinoletiferum sp. nov. parasitizing marine dinoflagellates. HARMFUL ALGAE 2024; 132:102567. [PMID: 38331547 DOI: 10.1016/j.hal.2024.102567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/29/2023] [Accepted: 01/02/2024] [Indexed: 02/10/2024]
Abstract
Oomycetes are fungus-like heterotrophic organisms with a broad environmental distribution, including marine, freshwater, and terrestrial habitats. They function as saprotrophs that use the remains of other organisms or as parasites of a variety of eukaryotes, including protists, diatoms, dinoflagellates, macroalgae, plants, fungi, animals, and even other oomycetes. Among the protist hosts, the taxonomy, morphology, and phylogenetic positions of the oomycete parasitoids of diatoms have been well studied; however, this information concerning the oomycete parasitoids of dinoflagellates is poorly understood. During intensive sampling along the east and west coasts of Korea in May and October 2019, a new species of oomycetes was discovered and two strains of the new parasitoid were successfully established in cultures. The new oomycete parasitoid penetrated the dinoflagellate host cell and developed to form a sporangium, which was very similar to the perkinsozoan parasitoids that infect marine dinoflagellates. The most distinctive morphological feature of the new parasitoid was a central large vacuole forming several long discharge tubes. The molecular phylogenetic tree inferred based on the small subunit (SSU) ribosomal DNA (rDNA) revealed that the new parasitoid forms a distinct branch unrelated to other described species belonging to early-diverging oomycetes. It clustered with species belonging to the genus Sirolpidium with strong support values in the cytochrome c oxidase subunit 2 (cox2) tree. Cross-infection experiments showed that infections by the new parasitoid occurred in only six genera belonging to dinoflagellates among the protists tested in this study. Based on the morphological and molecular data obtained in this study, we propose to introduce a new species, Sirolpidium dinoletiferum sp. nov., for this novel parasitoid, conservatively within the genus Sirolpidium.
Collapse
Affiliation(s)
- Boo Seong Jeon
- Research Institute for Basic Sciences, Chonnam National University, Gwangju 61186, Korea
| | - Myung Gil Park
- LOHABE, Department of Oceanography, Chonnam National University, Gwangju 61186, Korea.
| |
Collapse
|
3
|
Buaya A, Thines M. Ducellierialesord. nov. and evidence for a novel clade of endobiotic pollen-infecting "lagenidiaceous" Peronosporomycetes. Fungal Syst Evol 2023; 12:247-254. [PMID: 38455952 PMCID: PMC10918624 DOI: 10.3114/fuse.2023.12.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/31/2023] [Indexed: 03/09/2024] Open
Abstract
The genus Ducellieria (Ducellieriaceae) contains three species (D. chodatii, D. tricuspidata, D. corcontica), and a single variety (D. chodatii var. armata) of obligate endobiotic pollen parasites. These organisms have been first assigned to the green alga genus Coelastrum, as they form very similar spherical structures, but the observation of heterokont zoospores has led to their reclassification to the phylum Oomycota. However, despite their widespread nature, these organisms are only known from their descriptive morphology, and life cycle traits of some species still remain incompletely known. Only the type species, D. chodatii, has been rediscovered several times, but the phylogeny of the genus remains unresolved, since none of its species has been studied for their molecular phylogeny. At present the genus is still included in some algal databases. To clarify the evolutionary affiliation of Ducellieria, efforts were undertaken to isolate D. chodatii from pollen grains, to infer its phylogenetic placement based on nrSSU sequences. By targeted isolation, the pollen endoparasitoid was rediscovered from three lakes in Germany (Mummelsee, Okertalsperre, Knappensee). Apart from the typical coelastrum-like spheroids, oomycetes sporulating directly from pollen grains in a lagenidium-like fashion were observed, and molecular sequences of both types of oomycetes were obtained. Phylogenetic reconstruction revealed that coelastrum-like and lagenidium-like forms are unrelated, with the former embedded within the deep branching early-diverging lineages, and the later stage forming a distinct clade in Peronosporales. Consequently, the life cycle of D. chodatii needs careful revision using single-spore isolates of the species, to infer if previous lifecycle reconstructions that involve various different thallus types are stages of a single species or potentially of several ones. Citation: Buaya AT, Thines M (2023). Ducellieriales ord. nov. and evidence for a novel clade of endobiotic pollen-infecting "lagenidiaceous" Peronosporomycetes. Fungal Systematics and Evolution 12: 247-254. doi: 10.3114/fuse.2023.12.12.
Collapse
Affiliation(s)
- A.T. Buaya
- Goethe-Universität Frankfurt am Main, Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Max-von-Laue Str. 13, D-60438 Frankfurt am Main, Germany
- Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany
| | - M. Thines
- Goethe-Universität Frankfurt am Main, Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Max-von-Laue Str. 13, D-60438 Frankfurt am Main, Germany
- Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany
| |
Collapse
|
4
|
Salgado-Salazar C, Romberg M, Hudelson B. Plasmopara echinaceae, a new species of downy mildew affecting cone flowers ( Echinacea purpurea) in the United States. Fungal Syst Evol 2023; 12:203-217. [PMID: 38529086 PMCID: PMC10962218 DOI: 10.3114/fuse.2023.12.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 08/31/2023] [Indexed: 03/27/2024] Open
Abstract
Downy mildew is one of the most important diseases of commercial sunflower and other Asteraceae hosts, including ornamental Rudbeckia. Plasmopara halstedii has historically been identified as the causal agent of this disease, considered a complex of species affecting nearly 35 genera in various tribes. However, with the use of molecular DNA characters for phylogenetic studies, distinct lineages of P. halstedii in the Asteraceae have been identified, confirmed as distinct or segregated as new species. During August of 2022, a downy mildew was observed on potted Echinacea purpurea grown in a retail greenhouse in Jefferson County, Wisconsin, USA. Phylogenetic analyses of the cytochrome c oxidase subunit 2 (cox2) and nuclear large subunit ribosomal RNA (nc LSU rDNA) gene regions indicated these Plasmopara sp. isolates are not conspecific with P. halstedii. Based on phylogenetic evidence and new host association, the Plasmopara isolates from E. purpurea are here described as Plasmopara echinaceae. Diagnostic morphological characters for this new species were not observed when compared with other isolates of P. halstedii or other Plasmopara species found on Asteraceae hosts, and therefore a list of species-specific substitutions in the cox2 region are provided as diagnostic characters. As this study corresponds to the first observation of downy mildew in cone flowers, it is recommended to follow the required disease prevention guidelines to prevent outbreaks and the establishment of this plant pathogen in production sites. Citation: Salgado-Salazar C, Romberg MK, Hudelson B (2023). Plasmopara echinaceae, a new species of downy mildew affecting cone flowers (Echinacea purpurea) in the United States. Fungal Systematics and Evolution 12: 203-217. doi: 10.3114/fuse.2023.12.10.
Collapse
Affiliation(s)
- C. Salgado-Salazar
- Mycology and Nematology Genetic Diversity and Biology Laboratory, U.S. Department of Agriculture, Agriculture Research Service (USDA-ARS), 10300 Baltimore Avenue, Beltsville MD, 20705, USA
| | - M.K. Romberg
- National Identification Services, Plant Protection and Quarantine, U.S. Department of Agriculture, Animal and Plant Health Inspection Service (USDA-APHIS), 10300 Baltimore Avenue, Beltsville, MD, 20705, USA
| | - B. Hudelson
- Plant Disease Diagnostics Clinic, Department of Plant Pathology, University of Wisconsin-Madison, 1630 Linden Drive Madison, WI, 53706, USA
| |
Collapse
|
5
|
Lee SH, Nam B, Lee DJ, Choi YJ. Morphology, Molecular Phylogeny, and Fungicide Sensitivity of Phytophthora nagaii and P. tentaculata in Korea. MYCOBIOLOGY 2023; 51:333-342. [PMID: 37929005 PMCID: PMC10621251 DOI: 10.1080/12298093.2023.2265579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 09/18/2023] [Indexed: 11/07/2023]
Abstract
Phytophthora species, classified under Oomycota, cause significant damage to various crops and trees. The present study introduced Phytophthora species, P. nagaii and P. tentaculata, new to Korea, which pose notable risks to their respective host plants. Our research provided a comprehensive description of these species taking into account their cultural features, morphological characteristics, and molecular phylogenetic analysis using the internal transcribed spacer rDNA region and cytochrome c oxidase subunit mtDNA genes (cox1 and cox2) sequences. In addition, this study first evaluated the sensitivity of P. nagaii and P. tentaculata to five anti-oomycete fungicides, finding both species most responsive to picarbutrazox and P. tentaculata resistant to fluazinam. The data can guide targeted treatment strategies and offer insights into effective control methods. The findings expand our understanding of the diversity, distribution, and management of Phytophthora species in Korea.
Collapse
Affiliation(s)
- Seung Hyun Lee
- Department of Biological Science, Kunsan National University, Gunsan, South Korea
| | - Bora Nam
- Department of Biological Science, Kunsan National University, Gunsan, South Korea
- Center for Convergent Agrobioengineering, Kunsan National University, Gunsan, South Korea
| | - Dong Jae Lee
- Department of Biological Science, Kunsan National University, Gunsan, South Korea
| | - Young-Joon Choi
- Department of Biological Science, Kunsan National University, Gunsan, South Korea
- Center for Convergent Agrobioengineering, Kunsan National University, Gunsan, South Korea
| |
Collapse
|
6
|
Tsai I, Thines M. Adding a missing piece to the puzzle of oomycete phylogeny: the placement of Rhipidium interruptum ( Rhipidiaceae). Fungal Syst Evol 2023; 11:95-108. [PMID: 38562587 PMCID: PMC10983831 DOI: 10.3114/fuse.2023.11.08] [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: 04/13/2023] [Accepted: 06/06/2023] [Indexed: 04/04/2024] Open
Abstract
Oomycetes are a group of fungus-like organisms, which phylogenetically comprise early diverging lineages that are mostly holocarpic, and two crown classes, the Peronosporomycetes and Saprolegniomycetes, including many well-investigated pathogens of plants and animals. However, there is a poorly studied group, the Rhipidiales, which placement amongst the crown oomycetes is ambiguous. It accommodates several taxa with a sophisticated vegetative and reproductive cycle, as well as structural organisation, that is arguably the most complex in the oomycete lineage. Despite the remarkable morphological complexity and their notable perseverance in the face of faster-growing saprotrophic oomycetes and fungi, the knowledge on Rhipidiales is limited to date, as the most complex members are not easily cultured, even by targeted approaches. This also leads to inadequate sequence data for the order, which was sourced from only the two least complex out of seven introduced genera, i.e. Sapromyces and Salispina. In the present study, ex-situ baiting was done using various fruit substrates, and naturally-shed twigs or fruits acquired from water bodies were examined. As a result of these efforts, the species Rhipidium interruptum was obtained and gross cultivation was accomplished using poplar (Populus nigra) twigs as substrate, which allowed further documentation of both asexual and sexual reproduction. This enabled phylogenetic and detailed morphological study, as well as an epitypification of the species. Phylogenetic analyses based on cox2 and nrLSU sequences revealed Rhipidium as the sister genus of Sapromyces. The morphological studies done support a conspecificity of R. interruptum and R. continuum, which might in turn be conspecific with R. americanum. Though several further studies will be required to fit the scattered missing pieces of knowledge on Rhipidiales together revealing a more complete picture of oomycete evolution, we hope that the current study can serve as a cornerstone for future investigations in the group. Citation: Tsai I, Thines M (2023). Adding a missing piece to the puzzle of oomycete phylogeny: the placement of Rhipidium interruptum (Rhipidiaceae). Fungal Systematics and Evolution 11: 95-108. doi: 10.3114/fuse.2023.11.08.
Collapse
Affiliation(s)
- I. Tsai
- Evolutionary Analyses and Biological Archives, Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany
- Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University Frankfurt am Main, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany
| | - M. Thines
- Evolutionary Analyses and Biological Archives, Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany
- Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University Frankfurt am Main, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany
| |
Collapse
|
7
|
Benavent-Celma C, McLaggan D, van West P, Woodward S. Evidence of a Natural Hybrid Oomycete Isolated from Ornamental Nursery Stock. J Fungi (Basel) 2023; 9:627. [PMID: 37367563 DOI: 10.3390/jof9060627] [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: 05/26/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023] Open
Abstract
The oomycete genus Phytophthora includes many plant pathogens important in agricultural and environmental systems. Natural interspecific hybridization has been reported several times in Phytophthora, and although the fundamental processes of interspecific hybridization and the consequences of subsequent ecological distribution are poorly understood, reports suggest some hybrids can infect a broader host range and display enhanced virulence compared to the putative parental species. During a survey carried out at the University of Aberdeen in 2014-2015, of oomycetes present in ornamental plants purchased via the internet, a batch of oomycete isolates remained unidentified, showing, in some isolates, features generally related to hybridization. The aim of this study was to determine whether hybridization events had occurred between endemic and introduced oomycetes, probably/possibly facilitated through the international plant trade. The list of isolates examined included a putative hybrid closely related to Phytophthora cryptogea. The putative hybrid isolate was further characterized, and pathogenicity were tests carried out on Eucalyptus globulus, using an isolate of P. cryptogea as a positive control. Cloning of ITS, COXI and β-tubulin genes resulted in different sequence versions of the putative hybrid isolate; after mapping and a polymorphism position comparison, it was concluded that the studied isolate contained genetic information from P. cryptogea, P. erythroseptica, P. kelmanii, P. sansomeana and Phytopythium chamaehyphon. A PCR-RFLP assay, a NEBcutter analysis and flow cytometry analysis (genomes ranged between 0.168 to 0.269 pg/2C) added further evidence of the hybrid nature of this isolate. The putative hybrid presented complex growing patterns ranging from rosaceous to chrysanthemum-like and had an optimum growth temperature of 25 °C. Although the putative hybrid produced visible symptoms of disease on E. globulus seedlings, assessment of the relative susceptibility of E. globulus to P. cryptogea and the putative hybrid indicated that P. cryptogea was significantly more virulent than the putative hybrid, based on mortality, disease severity and foliar symptoms.
Collapse
Affiliation(s)
- Clara Benavent-Celma
- Department of Plant and Soil Science, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, Scotland, UK
- International Centre for Aquaculture Research and Development (ICARD), Aberdeen Oomycete Laboratory, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
- Environmental and Biochemical Sciences Department, The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland, UK
| | - Debbie McLaggan
- International Centre for Aquaculture Research and Development (ICARD), Aberdeen Oomycete Laboratory, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Pieter van West
- International Centre for Aquaculture Research and Development (ICARD), Aberdeen Oomycete Laboratory, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Steve Woodward
- Department of Plant and Soil Science, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, Scotland, UK
| |
Collapse
|
8
|
Jung T, Balci Y, Broders KD, Milenković I, Janoušek J, Kudláček T, Đorđević B, Horta Jung M. Synchrospora gen. nov., a New Peronosporaceae Genus with Aerial Lifestyle from a Natural Cloud Forest in Panama. J Fungi (Basel) 2023; 9:jof9050517. [PMID: 37233228 DOI: 10.3390/jof9050517] [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: 03/14/2023] [Revised: 04/20/2023] [Accepted: 04/23/2023] [Indexed: 05/27/2023] Open
Abstract
During a survey of Phytophthora diversity in Panama, fast-growing oomycete isolates were obtained from naturally fallen leaves of an unidentified tree species in a tropical cloud forest. Phylogenetic analyses of sequences from the nuclear ITS, LSU and ßtub loci and the mitochondrial cox1 and cox2 genes revealed that they belong to a new species of a new genus, officially described here as Synchrospora gen. nov., which resided as a basal genus within the Peronosporaceae. The type species S. medusiformis has unique morphological characteristics. The sporangiophores show determinate growth, multifurcating at the end, forming a stunted, candelabra-like apex from which multiple (8 to >100) long, curved pedicels are growing simultaneously in a medusa-like way. The caducous papillate sporangia mature and are shed synchronously. The breeding system is homothallic, hence more inbreeding than outcrossing, with smooth-walled oogonia, plerotic oospores and paragynous antheridia. Optimum and maximum temperatures for growth are 22.5 and 25-27.5 °C, consistent with its natural cloud forest habitat. It is concluded that S. medusiformis as adapted to a lifestyle as a canopy-dwelling leaf pathogen in tropical cloud forests. More oomycete explorations in the canopies of tropical rainforests and cloud forests are needed to elucidate the diversity, host associations and ecological roles of oomycetes and, in particular, S. medusiformis and possibly other Synchrospora taxa in this as yet under-explored habitat.
Collapse
Affiliation(s)
- Thomas Jung
- Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00 Brno, Czech Republic
- Phytophthora Research and Consultancy, 83131 Nußdorf, Germany
| | - Yilmaz Balci
- USDA-APHIS Plant Protection and Quarantine, 4700 River Road, Riverdale, MD 20737, USA
| | - Kirk D Broders
- Smithsonian Tropical Research Institute, Apartado Panamá, Panama City 0843-03092, Panama
- USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit, Peoria, IL 61604, USA
| | - Ivan Milenković
- Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00 Brno, Czech Republic
- Faculty of Forestry, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia
| | - Josef Janoušek
- Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00 Brno, Czech Republic
| | - Tomáš Kudláček
- Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00 Brno, Czech Republic
| | - Biljana Đorđević
- Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00 Brno, Czech Republic
| | - Marilia Horta Jung
- Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00 Brno, Czech Republic
- Phytophthora Research and Consultancy, 83131 Nußdorf, Germany
| |
Collapse
|
9
|
Fondevilla S, Arias-Giraldo LF, García-León FJ, Landa BB. Molecular Characterization of Peronospora variabilis Isolates Infecting Chenopodium quinoa and Chenopodium album in Spain. PLANT DISEASE 2023; 107:999-1004. [PMID: 36190302 DOI: 10.1094/pdis-05-22-1198-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: 06/16/2023]
Abstract
Quinoa is an expanding crop in southern Spain. Downy mildew, caused by Peronospora variabilis, is the most important quinoa disease in Spain and worldwide. In Spain, this disease has also been observed on the weed Chenopodium album. The objectives of this study were to unravel the origin of the P. variabilis isolates currently infecting quinoa in southern Spain and to study their genetic diversity. We hypothesized that P. variabilis isolates infecting quinoa in Spain could have been introduced through the seeds of the quinoa varieties currently grown in the country or, alternatively, that these isolates are endemic isolates, originally infecting C. album, that jumped to quinoa. In order to test these hypotheses, we sequenced the internal transcribed spacer (ITS), cytochrome c oxidase subunit 1 (cox1), and cox2 regions of 33 P. variabilis isolates infecting C. quinoa and C. album in southern Spain and analyzed their phylogenetic relationship with isolates present in other countries infecting Chenopodium spp. cox1 gene sequences from all of the Spanish P. variabilis isolates were identical and exhibited nine single-nucleotide polymorphisms (SNPs) compared with a single P. variabilis cox1 sequence found at GenBank. Phylogenetic analyses based on the ITS ribosomal DNA region were not suitable to differentiate isolates according to their geographical origin or host. The cox2 sequences from P. variabilis Spanish isolates collected from C. quinoa and C. album were all identical and had a distinctive SNP in the last of four polymorphic sites that distinguished Spanish isolates from isolates from other countries. These results suggest that P. variabilis infecting quinoa in southern Spain could be native isolates that originally infected C. album.[Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
Collapse
Affiliation(s)
- Sara Fondevilla
- Institute for Sustainable Agriculture, CSIC, Av. Menendez Pidal s/n, Córdoba 14004, Spain
| | - Luis F Arias-Giraldo
- Institute for Sustainable Agriculture, CSIC, Av. Menendez Pidal s/n, Córdoba 14004, Spain
| | | | - Blanca B Landa
- Institute for Sustainable Agriculture, CSIC, Av. Menendez Pidal s/n, Córdoba 14004, Spain
| |
Collapse
|
10
|
Nam B, Nguyen TTT, Lee HB, Park SK, Choi YJ. Uncharted Diversity and Ecology of Saprolegniaceae ( Oomycota) in Freshwater Environments. MYCOBIOLOGY 2022; 50:326-344. [PMID: 36404897 PMCID: PMC9645278 DOI: 10.1080/12298093.2022.2121496] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 06/16/2023]
Abstract
The fungal-like family Saprolegniaceae (Oomycota), also called "water mold," includes mostly aquatic saprophytes as well as notorious aquatic animal pathogens. Most studies on Saprolegniaceae have been biased toward pathogenic species that are important to aquaculture rather than saprotrophic species, despite the latter's crucial roles in carbon cycling of freshwater ecosystems. Few attempts have been made to study the diversity and ecology of Saprolegniaceae; thus, their ecological role is not well-known. During a survey of oomycetes between 2016 and 2021, we investigated the diversity and distribution of culturable Saprolegniaceae species in freshwater ecosystems of Korea. In the present study, members of Saprolegniaceae were isolated and identified at species level based on their cultural, morphological, and molecular phylogenetic analyses. Furthermore, substrate preference and seasonal dynamics for each were examined. Most of the species were previously reported as animal pathogens; however, in the present study, they were often isolated from other freshwater substrates, such as plant debris, algae, water, and soil sediment. The relative abundance of Saprolegniaceae was higher in the cold to cool season than that in the warm to hot season of Korea. This study enhances our understanding of the diversity and ecological attributes of Saprolegniaceae in freshwater ecosystems.
Collapse
Affiliation(s)
- Bora Nam
- Department of Biological Science, College of Natural Sciences, Kunsan National University, Gunsan, South Korea
| | - Thuong T. T. Nguyen
- Department of Agricultural Biological Chemistry, College of Agriculture & Life Sciences, Environmental Microbiology Lab, Chonnam National University, Gwangju, South Korea
| | - Hyang Burm Lee
- Department of Agricultural Biological Chemistry, College of Agriculture & Life Sciences, Environmental Microbiology Lab, Chonnam National University, Gwangju, South Korea
| | - Sang Kyu Park
- Nakdonggang National Institute of Biological Resources (NNIBR), Sangju, South Korea
| | - Young-Joon Choi
- Department of Biological Science, College of Natural Sciences, Kunsan National University, Gunsan, South Korea
| |
Collapse
|
11
|
Giles G, Indermaur EJ, Gonzalez-Giron JL, Hermann TQ, Shelnutt S, Starr J, Myers K, Jensen S, Bergstrom GC, Crawford J, Hansen JL, Smart LB, Smart CD. First Report of Downy Mildew caused by Pseudoperonospora cannabina on Cannabis sativa in New York. PLANT DISEASE 2022; 107:1638. [PMID: 36269588 DOI: 10.1094/pdis-08-22-1930-pdn] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Hemp (Cannabis sativa <0.3% tetrahydrocannabinol) is an emerging crop used for grain, fiber, and cannabinoid production (Fike et al. 2020). In New York, hemp is grown both in controlled environment facilities, including greenhouses, and as a field crop. In August 2020, downy mildew-like symptoms were observed on leaves and inflorescence of hemp plants in a field research trial in Ithaca, NY. Several cultivars, including 'Auto CBD', were affected. Disease was severe with some plants reaching 75% disease severity at the individual plant level. In the most severely affected plots, there was no marketable yield. The disease was characterized by chlorotic and necrotic lesions producing sporangiophores under high humidity. Pigmented sporangia were produced on branched sporangiophores. On artificially inoculated leaves incubated at 18°C, 80% humidity, 12h light for 5d, sporangiophores produced 8-19 pigmented, lemon-shaped sporangia with mean ± SD dimensions of 25.2 ± 3.0 (18.9 to 30.4) x 18.2 ± 2.1 (14.6 to 23.2) µm (n=50). Each sporangium produced 2-5 zoospores after less than 45 min in water at room temperature (22°C). Sporangia were collected from sporulating lesions and DNA was extracted as outlined in Crowell et al. (2020). Fragments of the ribosomal internal transcribed spacer (ITS) region (White et al. 1990), the beta-tubulin ras-associated ypt1 gene (Moorman et al. 2002), and the mitochondrial cytochrome B oxidase subunit 2 (cox2) gene (Hudspeth et al. 2000) were amplified by PCR and sequenced bidirectionally. Sequences were deposited in GenBank under accession numbers OK086084, OM867581, and OM867580, respectively. BLAST searches using the amplified ITS and cox2 sequences resulted in 100% identity to Pseudoperonospora cannabina (HM636051.1, HM636003.1) with ypt1 aligning at 97.95% identity (382/390 bp) with P. cannabina (KJ651402.1). The molecular characterization identified the causal agent as P. cannabina. A representative isolate was deposited in the Cornell Plant Pathology Herbarium as CUP-070922. Sporangia were rinsed from detached leaves and used to confirm pathogenicity on whole plants. Ten 4-week-old 'Anka' plants were spray-inoculated until run off with a suspension of 1x104 sporangia mL-1. Ten control plants were sprayed with water. After inoculation, plants were placed in a 19˚C growth chamber with a 12-h photoperiod and misted for 30 min twice daily to maintain humidity above 80%. Sporangia and previously described symptoms were observed 7 days post-inoculation, while control plants were asymptomatic. The pathogen was reisolated onto detached leaves of 'Anka' from inoculated leaves where both sporangia and oospores were observed. The reisolated pathogen was confirmed morphologically and molecularly, through PCR amplification and bidirectional sequencing of the ITS, cox2, and ypt1 genes, as P. cannabina. To our knowledge, this is the first report of P. cannabina causing hemp downy mildew in New York. Depending on the severity and timing of infections, this disease could pose a significant threat to hemp production in the state. Other members of the genus, P. cubensis and P. humuli cause downy mildew on cucurbits and hops, respectively. As these can cause devastating diseases on their hosts, P. cannabina must be monitored with vigilance as an emerging pathogen (Purayannur et al. 2021; Savory et al. 2011). Literature Cited: Crowell, C. R., et al.2020. Plant Dis. 104:2949. DOI 10.1094/PDIS-04-20-0718-RE Fike, J. H., et al. 2020. Page 89 In: Sustainable Agriculture Reviews, vol 42. Springer, Cham, Switzerland. DOI 10.1007/978-3-030-41384-2_3 Hudspeth, D. S. S., et al. 2000. Mycologia 92:674. DOI 10.2307/3761425 Moorman, G. W., et al. 2002. Plant Dis. 86:1227. DOI 10.1094/PDIS.2002.86.11.1227 Purayannur, S., et al. 2021. Mol. Plant Pathol. 22:755. DOI 10.1111/mpp.13063 Savory, E. A., et al. 2011. Mol. Plant Pathol. 12:217. DOI 10.1111/j.1364-3703.2010.00670.x White, T. J., et al. 1990. Page 315 In: PCR Protocols. A Guide to Methods and Applications. Academic Press, San Diego, CA. DOI 10.1016/B978-0-12-372180-8.50042-1.
Collapse
Affiliation(s)
- Garrett Giles
- Cornell University, School of Integrative Plant Science, Geneva, New York, United States;
| | - Elizabeth J Indermaur
- Cornell University, School of Integrative Plant Science, Geneva, New York, United States;
| | | | - Taylere Q Hermann
- Cornell University, School of Integrative Plant Science, Geneva, New York, United States;
| | - Savanna Shelnutt
- Cornell University, School of Integrative Plant Science, Geneva, New York, United States;
| | - Jennifer Starr
- Cornell University, 5922, School of Integrative Plant Science, Ithaca, New York, United States;
| | - Kevin Myers
- Cornell University, School of Integrative Plant Science, Ithaca, New York, United States;
| | - Sandra Jensen
- Cornell University, School of Integrative Plant Science, Ithaca, New York, United States;
| | - Gary C Bergstrom
- Cornell University, Plant Pathology and Plant-Microbe Biology, 334 Plant Science Building, Ithaca, New York, United States, 15853-5904;
| | - Jamie Crawford
- Cornell University, 5922, Plant Breeding and Genetics, School of Integrative Plant Science, Ithaca, New York, United States;
| | - Julie L Hansen
- Cornell University, 5922, Plant Breeding and Genetics Section, Ithaca, New York, United States;
| | - Lawrence B Smart
- Cornell University, 5922, Horticulture Section, School of Integrative Plant Science, 630 West North St, 102 Hedrick Hall, Geneva, New York, United States, 14456;
| | - Christine D Smart
- Cornell University, School of Integrative Plant Science, Geneva, New York, United States;
| |
Collapse
|
12
|
Burgess TI, White D, Sapsford SJ. Comparison of Primers for the Detection of Phytophthora (and Other Oomycetes) from Environmental Samples. J Fungi (Basel) 2022; 8:jof8090980. [PMID: 36135707 PMCID: PMC9502258 DOI: 10.3390/jof8090980] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/04/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Many oomycetes are important plant pathogens that cause devastating diseases in agricultural fields, orchards, urban areas, and natural ecosystems. Limitations and difficulties associated with isolating these pathogens have led to a strong uptake of DNA metabarcoding and mass parallel sequencing. At least 21 primer combinations have been designed to amplify oomycetes, or more specifically, Phytophthora species, from environmental samples. We used the Illumina sequencing platform to compare 13 primer combinations on mock communities and environmental samples. The primer combinations tested varied significantly in their ability to amplify Phytophthora species in a mock community and from environmental samples; this was due to either low sensitivity (unable to detect species present in low concentrations) or a lack of specificity (an inability to amplify some species even if they were present in high concentrations). Primers designed for oomycetes underestimated the Phytophthora community compared to Phytophthora-specific primers. We recommend using technical replicates, primer combinations, internal controls, and a phylogenetic approach for assigning a species identity to OTUs or ASVs. Particular care must be taken if sampling substrates where hybrid species could be expected. Overall, the choice of primers should depend upon the hypothesis being tested.
Collapse
Affiliation(s)
- Treena I. Burgess
- Phytophthora Science and Management, Harry Butler Institute, Murdoch 6150, Australia
- Correspondence:
| | - Diane White
- Phytophthora Science and Management, Harry Butler Institute, Murdoch 6150, Australia
| | - Sarah J. Sapsford
- Phytophthora Science and Management, Harry Butler Institute, Murdoch 6150, Australia
- School of Biological Science, University of Canterbury, Christchurch 8401, New Zealand
| |
Collapse
|
13
|
Characterisation of Pythium aristosporum Oomycete—A Novel Pathogen Causing Rice Seedling Blight in China. J Fungi (Basel) 2022; 8:jof8090890. [PMID: 36135615 PMCID: PMC9503656 DOI: 10.3390/jof8090890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/19/2022] [Accepted: 08/20/2022] [Indexed: 11/17/2022] Open
Abstract
Rice seedling blight is a globally occurring seedling disease caused by multiple pathogens. It is currently the most common disease affecting rice production in northeast China; hence, determining the causal agents, including its biological characteristics, host range, and fungicide efficacy is vital for its effective management. The present study obtained 45 pathogenic isolates from diseased rice seedlings in Suihua, Heilongjiang Province, China. Of these, five pathogens were identified based on their morphology and molecular identification, while 10 oomycete isolates were identified as Pythium aristosporum—the first to be reported in rice seedling blight. Its optimum growth conditions include a temperature of 25 °C, pH 6, and photoperiod of 24 h. Except for soybean (Glycine max (L.) Merr.), black soybean (Glycine max var.), and cucumber (Cucumis sativus L.), P. aristosporum can potentially infect and cause seedling blight on other hosts, such as wheat (Triticum aestivum L.), maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench), alfalfa (Medicago sativa L.), oats (Avena sativa L.), and white clover (Trifolium repens L.). Its isolates were found to be highly sensitive to metalaxyl + propamocarb (EC50 = 0.0138 μg/mL) with 84.1% efficacy at 313 μg/mL. These results can serve as the basis for controlling P. aristosporum.
Collapse
|
14
|
Rapid detection of 5 fungal diseases in sunflower (Helianthus annuus) using dual priming oligonucleotide system-based multiplex PCR and capillary electrophoresis. SLAS Technol 2022; 27:253-260. [DOI: 10.1016/j.slast.2022.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 11/18/2022]
|
15
|
Salgado-Salazar C, Thines M. Two new species of Plasmopara affecting wild grapes in the USA. Mycol Prog 2022. [DOI: 10.1007/s11557-022-01813-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
16
|
Rooney-Latham S, Blomquist CL, Pastalka T, Soriano MC. First Report of Dieback Caused by Phytophthora ramorum on Golden Chinquapin, Chrysolepis chrysophylla, in California. PLANT DISEASE 2022; 106:PDIS09212044PDN. [PMID: 35124991 DOI: 10.1094/pdis-09-21-2044-pdn] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Affiliation(s)
- S Rooney-Latham
- California Department of Food and Agriculture Plant Pest Diagnostics Center (PPDC), Sacramento, CA 95832-1448
| | - C L Blomquist
- California Department of Food and Agriculture Plant Pest Diagnostics Center (PPDC), Sacramento, CA 95832-1448
| | - T Pastalka
- Department of Natural Sciences and Mathematics, Dominican University of California, San Rafael, CA 94901
| | - M C Soriano
- California Department of Food and Agriculture Plant Pest Diagnostics Center (PPDC), Sacramento, CA 95832-1448
| |
Collapse
|
17
|
Mirzaee MR, Ploch S, Thines M. A new desert-dwelling oomycete, Pustula persica sp. nov., on Gymnarrhena micrantha ( Asteraceae) from Iran. MYCOSCIENCE 2021; 62:239-243. [PMID: 37092169 PMCID: PMC9721518 DOI: 10.47371/mycosci.2021.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 11/16/2022]
Abstract
The obligate biotrophic oomycete genus Pustula is one of the four major linages of white blister rusts (Albuginaceae) identified so far. Species of the genus Pustula cause white blister rust on numerous genera in the asterids, represented by several phylogenetically distinct genus-specific lineages, most of which still await formal description. Thus, the observation of the species of Pustula on the Asteraceae subfamily Gymnorhenoideae pointed out to the existence of a hitherto undescribed species. By the morphological and molecular phylogenetic investigation conducted in this study it is concluded that the pathogen on Gymnarrhena micrantha from Iran indeed represents a hitherto unknown species and is described as P. persica. This species has apparently adapted to desert condition and is, after Albugo arenosa, the second species of white blister rust from Iranian deserts, highlighting the adaptability of white blister rusts to hot and dry habitats.
Collapse
Affiliation(s)
- Mohammad Reza Mirzaee
- Plant Protection Research Department, South Khorasan Agricultural and Natural Resources Research and Education Center, AREEO
| | | | - Marco Thines
- Senckenberg Biodiversity and Climate Research Centre
| |
Collapse
|
18
|
Decloquement J, Ramos-Sobrinho R, Elias SG, Britto DS, Puig AS, Reis A, da Silva RAF, Honorato-Júnior J, Luz EDMN, Pinho DB, Marelli JP. Phytophthora theobromicola sp. nov.: A New Species Causing Black Pod Disease on Cacao in Brazil. Front Microbiol 2021; 12:537399. [PMID: 33815301 PMCID: PMC8015942 DOI: 10.3389/fmicb.2021.537399] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 02/18/2021] [Indexed: 12/12/2022] Open
Abstract
Black pod disease, caused by Phytophthora species, is among the main limiting factors of cacao (Theobroma cacao L.) production. High incidence levels of black pod disease have been reported in Brazil, being induced by Phytophthora capsici, Phytophthora citrophthora, Phytophthora heveae, and Phytophthora palmivora. To assess the diversity of Phytophthora species affecting cacao in Brazil, 40 new isolates were obtained from cacao pods exhibiting symptoms of black pod disease collected in different smallholder farms in 2017. Further, ten cacao-infecting isolates morphologically identified as P. citrophthora and P. palmivora were molecularly characterized. The genomic regions beta-tubulin, elongation factor 1 alpha, heat shock protein 90, and internal transcribed spacer, and the mitochondrially encoded cytochrome c oxidase I and II genes were PCR-amplified and Sanger-sequenced from the cacao-infecting Phytophthora isolates. The morphological characterization and evaluation of the mycelial growth rates for the Phytophthora isolates were performed in vitro. Based on the molecular analysis and morphological comparisons, 19 isolates were identified as P. palmivora (clade 4). Interestingly, 31 isolates grouped together in the phylogenetic tree and were placed apart from previously known species in Phytophthora clade 2. Therefore, these isolates are considered as a new species herein referred to as Phytophthora theobromicola sp. nov., which produced papillate, semipapillate, and persistent sporangia on simple sporangiophores. The P. palmivora isolates were identified as A1 mating type by pairing each isolate with known A1 and A2 tester strains of P. capsici, but no oogonia/antheridia were observed when P. theobromicola was paired with the different tester strains. The P. theobromicola and P. citrophthora isolates showed higher mycelial growth rates, when compared to P. palmivora, on different media at 10, 15, and 20°C, but similar values were observed when grown on clarified CA media at 25 and 30°C. The pathogenicity tests carried out on pods of four cacao clones (CCN51, PS1319, Cepec2004, and CP49) showed significant variability among the isolates of both Phytophthora species, with P. theobromicola inducing higher rates of necrotic lesion expansion, when compared to P. palmivora. Here, two Phytophthora species were found associated with black pod disease in the state of Bahia, Brazil, and the previously undescribed P. theobromicola seems to be prevalent in field conditions. This is the first report of P. theobromicola on T. cacao. Also, these findings are crucial to improve the disease control strategies, and for the development of cacao materials genetically resistant to Phytophthora.
Collapse
Affiliation(s)
| | | | | | | | - Alina Sandra Puig
- USDA-ARS/Subtropical Horticultural Research Station, Miami, FL, United States
| | - Ailton Reis
- Embrapa, Centro Nacional de Pesquisa de Hortaliças, Brasília, Brazil
| | | | - Jaime Honorato-Júnior
- Centro Multidisciplinar do Campus de Barra, Universidade Federal do Oeste da Bahia, Barra, Brazil
| | | | | | | |
Collapse
|
19
|
Lee DJ, Lee JS, Choi YJ. Co-Occurrence of Two Phylogenetic Clades of Pseudoperonospora cubensis, the Causal Agent of Downy Mildew Disease, on Oriental Pickling Melon. MYCOBIOLOGY 2021; 49:188-195. [PMID: 37970181 PMCID: PMC10635115 DOI: 10.1080/12298093.2021.1880310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/08/2021] [Accepted: 01/19/2021] [Indexed: 11/17/2023]
Abstract
The genus Pseudoperonospora, an obligate biotrophic group of Oomycota, causes the most destructive foliar downy mildew disease on many economically important crops and wild plants. A previously unreported disease by Pseudoperonospora was found on oriental pickling melon (Cucumis melo var. conomon) in Korea, which is a minor crop cultivated in the temperate climate zone of East Asia, including China, Korea, and Japan. Based on molecular phylogenetic and morphological analyses, the causal agent was identified as Pseudoperonospora cubensis, and its pathogenicity has been proven. Importantly, two phylogenetic clades of P. cubensis, harboring probably two distinct species, were detected within the same plots, suggesting simultaneous coexistence of the two clades. This is the first report of P. cubensis causing downy mildew on oriental pickling melon in Korea, and the confirmation of presence of two phylogenetic clades of this pathogen in Korea. Given the high incidence of P. cubensis and high susceptibility of oriental pickling melon to this disease, phytosanitary measures, including rapid diagnosis and effective control management, are urgently required.
Collapse
Affiliation(s)
- Dong Jae Lee
- Department of Biology, Kunsan National University, Gunsan, Korea
| | - Jae Sung Lee
- Department of Biology, Kunsan National University, Gunsan, Korea
| | - Young-Joon Choi
- Department of Biology, Kunsan National University, Gunsan, Korea
| |
Collapse
|
20
|
Barboza EA, Cabral CS, Rossato M, Luz EDMN, Reis A. Morphologic, molecular, and pathogenic characterization of Phytophthora palmivora isolates causing flower rot on azalea. Braz J Microbiol 2020; 51:1493-1503. [PMID: 32458260 DOI: 10.1007/s42770-020-00300-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/13/2020] [Indexed: 11/26/2022] Open
Abstract
The objective of this work was to characterize two Phytophthora palmivora isolates causing floral blight and rot in azalea plants and to evaluate the pathogenicity of this oomycete pathogen on several plant species. Azalea plants with symptoms of flower blight and rot were obtained in the municipality of Holambra-SP. After an attempt of isolation, colonies with Phytophthora characteristics grown only on selective V8 medium. Molecular identification of the isolates was done by amplification and sequencing of ITS and COX2 regions. In the phylogenetic analysis, the azalea isolates clustered with reference isolates of P. palmivora. Morphological characteristics were similar to those described for P. palmivora. Isolates were inoculated in healthy azalea plants and caused leaf blight and floral rot. The pathogen was re-isolated from symptomatic plants completing Koch's postulates. In a host range test, the azalea isolates were able to cause lesions on leaves of vinca, snapdragon, basil, and tomato, and affected both leaves and flowers of geranium. Fruit rot was observed on tomato, potato, sweet pepper, scarlet eggplant, zucchini, cucumber, maroon cucumber, onion, apple, papaya, guava, and carrot. This is the first report of the species P. palmivora causing flower blight and rot in azalea plants in Brazil and probably in the world.
Collapse
Affiliation(s)
| | | | - Maurício Rossato
- Departamento de Fitopatologia, Universidade de Brasília, Brasília, DF, Brazil
| | | | | |
Collapse
|
21
|
Lee JS, Shin HD, Choi YJ. Rediscovery of Seven Long-Forgotten Species of Peronospora and Plasmopara (Oomycota). MYCOBIOLOGY 2020; 48:331-340. [PMID: 33177913 PMCID: PMC7580582 DOI: 10.1080/12298093.2020.1798863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
The family Peronosporaceae, an obligate biotrophic group of Oomycota, causes downy mildew disease on many cultivated and ornamental plants such as beet, cucumber, grape, onion, rose, spinach, and sunflower. To investigate the diversity of Peronosporaceae species in Korea, we performed morphological analysis for dried plant herbariums with downy mildew infections by two largest genera, Peronospora and Plasmopara. As a result, it was confirmed that there are five species of Peronospora and two species of Plasmopara, which have been so far unrecorded in Korea, as well as rarely known in the world; Pl. angustiterminalis (ex Xanthium strumarium), Pl. siegesbeckiae (ex Siegesbeckia glabrescens), P. chenopodii-ambrosioidis (ex Chenopodium ambrosioides), P. chenopodii-ficifolii (ex Chenopodium ficifolium), P. clinopodii (ex Clinopodium cf. vulgare), P. elsholtziae (ex Elsholtzia ciliata), and P. lathyrina (ex Lathyrus japonicus). In addition, their phylogenetic relationship was inferred by molecular sequence analysis of ITS, LSU rDNA, and cox2 mtDNA. By rediscovering the seven missing species and barcoding their DNA sequences, this study provides valuable insights into the diversity and evolutionary studies of downy mildew pathogens.
Collapse
Affiliation(s)
- Jae Sung Lee
- Department of Biology, Kunsan National University, Gunsan, Korea
| | - Hyeon-Dong Shin
- Division of Environmental Science and Ecological Engineering, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea
| | - Young-Joon Choi
- Department of Biology, Kunsan National University, Gunsan, Korea
| |
Collapse
|
22
|
Human Pythiosis: Emergence of Fungal-Like Organism. Mycopathologia 2019; 185:801-812. [PMID: 31845178 DOI: 10.1007/s11046-019-00412-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 11/28/2019] [Indexed: 01/10/2023]
Abstract
Pythiosis is an emerging infectious disease caused by the aquatic oomycete Pythium insidiosum, a fungal-like organism. It is believed that P. insidiosum's zoospores, its infected form, play major role in pathogenesis. Vascular and ocular infections are the most common clinical manifestation in humans. It is difficult to establish the diagnosis given its relatively rarity and difficulty to distinguish P. insidiosum from other molds. Delay in diagnosis and treatment has been associated with poor outcomes. High index of suspicion is the key, particularly in thalassemia patients with arterial insufficiency and patients with fungal keratitis/endophthalmitis without improvement on antifungal therapy. Tissue culture and zoospore induction remain gold standard for diagnosis; however, DNA-based method should be performed simultaneously. The combination of radical surgery, antifungal agents, and immunotherapy has been recommended. It was previously believed that surgery with negative surgical margins was the essential to survive in vascular pythiosis; however, it was recently found that patients could have residual disease despite documented negative surgical margins as infected clot may be dislodged to proximal arterial sites prior to surgery. Serum β-D-glucan (BG) has been used to monitor disease response after treatment initiation in vascular pythiosis. A significant decrease in BG levels within 2 weeks after surgery is indicative of the absence of residual infection. Unfortunately, monitoring tools for ocular pythiosis are not yet available. Itraconazole plus terbinafine have generally been used in P. insidiosum-infected patients; however, antibacterial agents, including azithromycin and linezolid, have also been used with favorable outcomes in ocular disease. Recently, azithromycin or clarithromycin plus doxycyclin were used in two relapsed vascular pythiosis patients with good outcomes.
Collapse
|
23
|
Sarowar MN, Cusack R, Duston J. Saprolegnia molecular phylogeny among farmed teleosts in Nova Scotia, Canada. JOURNAL OF FISH DISEASES 2019; 42:1745-1760. [PMID: 31637741 DOI: 10.1111/jfd.13090] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
To identify the pathogens causing saprolegniosis among farmed fish in Nova Scotia, 172 infected tissues and 23 water samples were collected from six species of teleosts: Atlantic salmon (Salmo salar), brown trout (Salmo trutta), Arctic charr (Salvelinus alpinus), brook trout (Salvelinus fontinalis), striped bass (Morone saxatilis) and rainbow trout (Oncorhynchus mykiss) at nine facilities over a 600 km range. Following laboratory culture, 132 isolates were recovered. Six species of oomycetes were identified from analysis of the internal transcribed spacer (ITS) sequence of the nrDNA: Saprolegnia parasitica, Saprolegnia ferax, Saprolegnia diclina, Saprolegnia aenigmatica, Saprolegnia torulosa, Saprolegnia sp. and Pythiopsis cymosa. Further phylogenetic analyses of the ITS and cytochrome c oxidase subunit 1 (Cox1) regions revealed four strains of Saprolegnia parasitica (named here as S1, S2, S3 and S4), of which S1 and S2 were common (37% and 42% of the isolates), and two strains of S. ferax. Among S. parasitica, S2 and S3 are more closely related to each other than to S1 based on the phylogenetic analyses and predicted RNA secondary structure of the ITS region. Sexual structures with a similar morphology were formed by S1 and S3 in vitro, but were not formed by S2.
Collapse
Affiliation(s)
- Mohammad Nasif Sarowar
- Department of Animal Science and Aquaculture, Agricultural Campus, Dalhousie University, Bible Hill, Canada
| | - Roland Cusack
- Nova Scotia Department of Fisheries and Aquaculture, Agricultural Campus, Hancock Veterinary Building, Bible Hill, Canada
| | - James Duston
- Department of Animal Science and Aquaculture, Agricultural Campus, Dalhousie University, Bible Hill, Canada
| |
Collapse
|
24
|
Sapp M, Tyborski N, Linstädter A, López Sánchez A, Mansfeldt T, Waldhoff G, Bareth G, Bonkowski M, Rose LE. Site-specific distribution of oak rhizosphere-associated oomycetes revealed by cytochrome c oxidase subunit II metabarcoding. Ecol Evol 2019; 9:10567-10581. [PMID: 31624568 PMCID: PMC6787841 DOI: 10.1002/ece3.5577] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/23/2019] [Accepted: 07/28/2019] [Indexed: 01/19/2023] Open
Abstract
The phylum Oomycota comprises important tree pathogens like Phytophthora quercina, involved in central European oak decline, and Phytophthora cinnamomi shown to affect holm oaks among many other hosts. Despite the importance to study the distribution, dispersal and niche partitioning of this phylum, metabarcoding surveys, and studies considering environmental factors that could explain oomycete community patterns are still rare. We investigated oomycetes in the rhizosphere of evergreen oaks in a Spanish oak woodland using metabarcoding based on Illumina sequencing of the taxonomic marker cytochrome c oxidase subunit II (cox2). We developed an approach amplifying a 333 bp long fragment using the forward primer Hud-F (Mycologia, 2000) and a reverse primer found using DegePrime (Applied and Environmental Microbiology, 2014). Factors reflecting topo-edaphic conditions and tree health were linked to oomycete community patterns. The majority of detected OTUs belonged to the Peronosporales. Most taxa were relatives of the Pythiaceae, but relatives of the Peronosporaceae and members of the Saprolegniales were also found. The most abundant OTUs were related to Globisporangium irregulare and P. cinnamomi, both displaying strong site-specific patterns. Oomycete communities were strongly correlated with the environmental factors: altitude, crown foliation, slope and soil skeleton and soil nitrogen. Our findings illustrate the significance of small scale variation in habitat conditions for the distribution of oomycetes and highlight the importance to study oomycete communities in relation to such ecological patterns.
Collapse
Affiliation(s)
- Melanie Sapp
- Cluster of Excellence on Plant Sciences (CEPLAS)Population GeneticsHeinrich Heine UniversityDüsseldorfGermany
| | - Nicolas Tyborski
- Cluster of Excellence on Plant Sciences (CEPLAS)Population GeneticsHeinrich Heine UniversityDüsseldorfGermany
| | - Anja Linstädter
- Botanical Institute, Range Ecology and Range ManagementUniversity of CologneCologneGermany
- Institute of Crop Science and Resource Conservation (INRES)University of BonnBonnGermany
| | - Aida López Sánchez
- Botanical Institute, Range Ecology and Range ManagementUniversity of CologneCologneGermany
- Departamento de Sistemas y Recursos NaturalesUniversidad Politécnica de MadridMadridSpain
| | - Tim Mansfeldt
- Institute of GeographyUniversity of CologneCologneGermany
| | - Guido Waldhoff
- Institute of GeographyUniversity of CologneCologneGermany
| | - Georg Bareth
- Institute of GeographyUniversity of CologneCologneGermany
| | - Michael Bonkowski
- Cluster of Excellence on Plant Sciences (CEPLAS)Institute of ZoologyTerrestrial EcologyUniversity of CologneCologneGermany
| | - Laura E. Rose
- Cluster of Excellence on Plant Sciences (CEPLAS)Population GeneticsHeinrich Heine UniversityDüsseldorfGermany
| |
Collapse
|
25
|
Bennett RM, Devanadera MK, Dedeles GR. A revision of Salispina, its placement in a new family, Salispinaceae ( Rhipidiales), and description of a fourth species, S. hoi sp. nov. IMA Fungus 2018; 9:259-269. [PMID: 30622882 PMCID: PMC6317584 DOI: 10.5598/imafungus.2018.09.02.03] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 08/17/2018] [Indexed: 01/24/2023] Open
Abstract
The genus Salispina was recently described for saprotrophic estuarine oomycetes with aculeolate or spiny sporangia. The genus currently contains three species, S. intermedia, S. lobata, and S. spinosa, the latter two previously included in Halophytophthora. During a survey of mangrove-inhabiting oomycetes in the Philippines, an isolate of Salispina (USTCMS 1611), was obtained from a decaying mangrove leaf. This isolate differed from other species in the genus in a unique combination of morphological and biological characters. Phylogenetic analysis revealed it to be the sister lineage of S. lobata. Consequently, the new species name S. hoi is introduced for the isolate. In addition, Salispina spp. grouped with Sapromyces of Rhipidiales with strong support, but differs from all other known genera of the order in the weak formation of hyphal constrictions, and absence of basal thalli and a holdfast network. The new family Salispinaceae is, therefore, described to accommodate Salispina in the order Rhipidiales.
Collapse
Affiliation(s)
- Reuel M Bennett
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany
- Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University Frankfurt am Main, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
- Integrative Fungal Research Cluster (IPF), Georg-Voigt-Str. 14-16, D-60325 Frankfurt am Main, Germany
| | - Mark Kevin Devanadera
- Department of Biological Sciences-College of Science, Department of Biochemistry-Faculty of Pharmacy, and UST Collection of Microbial Strains (USTCMS), Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila 1015, Philippines
| | - Gina R Dedeles
- Department of Biological Sciences-College of Science, Department of Biochemistry-Faculty of Pharmacy, and UST Collection of Microbial Strains (USTCMS), Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila 1015, Philippines
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany
- Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University Frankfurt am Main, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
- Integrative Fungal Research Cluster (IPF), Georg-Voigt-Str. 14-16, D-60325 Frankfurt am Main, Germany
| |
Collapse
|
26
|
de Vries S, von Dahlen JK, Schnake A, Ginschel S, Schulz B, Rose LE. Broad-spectrum inhibition of Phytophthora infestans by fungal endophytes. FEMS Microbiol Ecol 2018; 94:4925062. [PMID: 29528408 PMCID: PMC5939626 DOI: 10.1093/femsec/fiy037] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/05/2018] [Indexed: 11/12/2022] Open
Abstract
Phytophthora infestans is a devastating pathogen of tomato and potato. It readily overcomes resistance genes and applied agrochemicals and hence even today causes large yield losses. Fungal endophytes provide a largely unexplored avenue of control of Phy. infestans. Not only do endophytes produce a wide array of bioactive metabolites, they may also directly compete with and defeat pathogens in planta. Here, we tested 12 fungal endophytes isolated from different plant species in vitro for their production of metabolites with anti- Phytophthora activity. Four well-performing isolates were evaluated for their ability to suppress nine isolates of Phy. infestans on agar medium and in planta. Two endophytes reliably inhibited all Phy. infestans isolates on agar medium, of which Phoma eupatorii isolate 8082 was the most promising. It nearly abolished infection by Phy. infestans in planta. Our data indicate a role for the production of anti-Phytophthora compounds by the fungus and/or an enhanced plant defense response, as evident by an enhanced anthocyanin production. Here, we present a potential biocontrol agent, which can inhibit a broad-spectrum of Phy. infestans isolates. Such broadly acting inhibition is ideal, because it allows for effective control of genetically diverse isolates and may slow the adaptation of Phy. infestans.
Collapse
Affiliation(s)
- Sophie de Vries
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
- iGRAD-Plant Graduate School, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Janina K von Dahlen
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| | - Anika Schnake
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| | - Sarah Ginschel
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| | - Barbara Schulz
- Institute of Microbiology, Technische Universitaet Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany
| | - Laura E Rose
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
- iGRAD-Plant Graduate School, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
- Ceplas, Cluster of Excellence in Plant Sciences, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| |
Collapse
|
27
|
Chalupová J, Raus M, Sedlářová M, Sebela M. Identification of fungal microorganisms by MALDI-TOF mass spectrometry. Biotechnol Adv 2013; 32:230-41. [PMID: 24211254 DOI: 10.1016/j.biotechadv.2013.11.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/24/2013] [Accepted: 11/03/2013] [Indexed: 12/26/2022]
Abstract
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as a reliable tool for fast identification and classification of microorganisms. In this regard, it represents a strong challenge to microscopic and molecular biology methods. Nowadays, commercial MALDI systems are accessible for biological research work as well as for diagnostic applications in clinical medicine, biotechnology and industry. They are employed namely in bacterial biotyping but numerous experimental strategies have also been developed for the analysis of fungi, which is the topic of the present review. Members of many fungal genera such as Aspergillus, Fusarium, Penicillium or Trichoderma and also various yeasts from clinical samples (e.g. Candida albicans) have been successfully identified by MALDI-TOF MS. However, there is no versatile method for fungi currently available even though the use of only a limited number of matrix compounds has been reported. Either intact cell/spore MALDI-TOF MS is chosen or an extraction of surface proteins is performed and then the resulting extract is measured. Biotrophic fungal phytopathogens can be identified via a direct acquisition of MALDI-TOF mass spectra e.g. from infected plant organs contaminated by fungal spores. Mass spectrometric peptide/protein profiles of fungi display peaks in the m/z region of 1000-20000, where a unique set of biomarker ions may appear facilitating a differentiation of samples at the level of genus, species or strain. This is done with the help of a processing software and spectral database of reference strains, which should preferably be constructed under the same standardized experimental conditions.
Collapse
Affiliation(s)
- Jana Chalupová
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Martin Raus
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Michaela Sedlářová
- Department of Botany, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Marek Sebela
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic.
| |
Collapse
|
28
|
Diéguez-Uribeondo J, García MA, Cerenius L, Kozubíková E, Ballesteros I, Windels C, Weiland J, Kator H, Söderhäll K, Martín MP. Phylogenetic relationships among plant and animal parasites, and saprotrophs in Aphanomyces (Oomycetes). Fungal Genet Biol 2009; 46:365-76. [PMID: 19236935 DOI: 10.1016/j.fgb.2009.02.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 02/18/2009] [Accepted: 02/18/2009] [Indexed: 11/18/2022]
Abstract
Molecular phylogenetic relationships among 12 species of Aphanomyces de Bary (Oomycetes) were analyzed based on 108 ITS sequences of nuclear rDNA. Sequences used in the analyses belonged to the major species currently available in pure culture and GenBank. Bayesian, maximum likelihood, and maximum parsimony analyses support that Aphanomyces constitutes a monophyletic group. Three independent lineages were found: (i) plant parasitic, (ii) animal parasitic, and (iii) saprotrophic or opportunistic parasitic. Sexual reproduction appeared to be critical in plant parasites for survival in soil environments while asexual reproduction seemed to be advantageous for exploiting specialization in animal parasitism. Repeated zoospore emergence seems to be an advantageous property for both plant and animal parasitic modes of life. Growth in unspecific media was generally faster in saprotrophs compared with parasitic species. A number of strains and GenBank sequences were found to be misidentified. It was confirmed molecularly that Aphanomyces piscicida and Aphanomyces invadans appear to be conspecific, and found that Aphanomyces iridis and Aphanomyces euteiches are closely related, if not the same, species. This study has shown a clear evolutionary separation between Aphanomyces species that are plant parasites and those that parasitize animals. Saprotrophic or opportunistic species formed a separate evolutionary lineage except Aphanomyces stellatus whose evolutionary position has not yet been resolved.
Collapse
|
29
|
Göker M, Voglmayr H, Riethmüller A, Weiß M, Oberwinkler F. Taxonomic aspects of Peronosporaceae inferred from Bayesian molecular phylogenetics. ACTA ACUST UNITED AC 2003. [DOI: 10.1139/b03-066] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We present the results of a Bayesian phylogenetic analysis of parts of the nuclear 28S rDNA of a representative sample of the Peronosporales. Peronospora s.l. is shown to be paraphyletic. Based on molecular and morphological evidence, several species of the genus Peronospora are transferred to Hyaloperonospora. Plasmopara oplismeni appears to be related only distantly to the other Plasmopara species, and is transferred to the new genus Viennotia based on molecular, morphological, and ecological evidence. The remaining Plasmopara species are likely to be paraphyletic with respect to Bremia, Paraperonospora, and Basidiophora. Phytophthora is shown to be paraphyletic with respect to the obligatory biotrophic genera. Evidence for the assumption that obligatory biotrophism arose independently at least twice in Peronosporales is demonstrated.Key words: LSU rDNA, Straminipila, Peronosporomycetes, Peronosporales, downy mildews, Bayesian phylogenetic analysis.
Collapse
|