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Buivydaitė Ž, Winding A, Sapkota R. Transmission of mycoviruses: new possibilities. Front Microbiol 2024; 15:1432840. [PMID: 38993496 PMCID: PMC11236713 DOI: 10.3389/fmicb.2024.1432840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 06/12/2024] [Indexed: 07/13/2024] Open
Abstract
Mycoviruses are viruses that infect fungi. In recent years, an increasing number of mycoviruses have been reported in a wide array of fungi. With the growing interest of scientists and society in reducing the use of agrochemicals, the debate about mycoviruses as an effective next-generation biocontrol has regained momentum. Mycoviruses can have profound effects on the host phenotype, although most viruses have neutral or no effect. We speculate that understanding multiple transmission modes of mycoviruses is central to unraveling the viral ecology and their function in regulating fungal populations. Unlike plant virus transmission via vegetative plant parts, seeds, pollen, or vectors, a widely held view is that mycoviruses are transmitted via vertical routes and only under special circumstances horizontally via hyphal contact depending on the vegetative compatibility groups (i.e., the ability of different fungal strains to undergo hyphal fusion). However, this view has been challenged over the past decades, as new possible transmission routes of mycoviruses are beginning to unravel. In this perspective, we discuss emerging studies with evidence suggesting that such novel routes of mycovirus transmission exist and are pertinent to understanding the full picture of mycovirus ecology and evolution.
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Affiliation(s)
| | | | - Rumakanta Sapkota
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
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Klimov PB, Kolesnikov VB, Khaustov VA, Khaustov AA. Thyreophagus tauricus sp. n., a New Subcortical Mite Species (Acari: Acaridae), with a COX1 DNA Sequence Analysis of Several Economically Important Species of Thyreophagus. Animals (Basel) 2023; 13:3546. [PMID: 38003163 PMCID: PMC10668731 DOI: 10.3390/ani13223546] [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: 10/16/2023] [Revised: 11/02/2023] [Accepted: 11/10/2023] [Indexed: 11/26/2023] Open
Abstract
As part of a survey of the subcortical astigmatic mites of Crimea, we discovered a new sexual acarid species, Thyreophagus tauricus sp. n. This species was cultured in the laboratory to correlate the adult and deutonymphal stages. Using specimens obtained by these rearing experiments, we provide a detailed description of Th. tauricus (light microscopy, SEM) based on females, males and heteromorphic deutonymphs. Furthermore, to facilitate molecular identification, the entire COX1 gene was also sequenced for this and three other Palearctic species reared in the lab as pure cultures. Adults of Th. tauricus sp. n. are distinct among all other species of the genus by the presence of flattened, button-shaped or minute spiniform setae s III and IV, which are well-developed spiniform in all other known species of Thyreophagus. Heteromorphic deutonymphs of Th. tauricus are distinct from all other species of Thyreophagus by the presence of well-developed setae cm on the dorsal part of the subcapitular remnant (absent all other species). Th. tauricus is morphologically very similar to Th. corticalis; however, COX1 K2P distances between these two species were large, 19.8%. COX1 K2P distances between Th. tauricus and other species (Th. entomophagus, Th. "entomophagus" NC 066986.1, Th. calusorum, Th. corticalis) ranged between 20.1 and 24.3%. We show that the GenBank sequence of Th. "entomophagus" from China (NC 066986.1) was probably misidentified.
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Affiliation(s)
- Pavel B. Klimov
- X-Bio Institute, Tyumen State University, 10 Semakova Str., 625003 Tyumen, Russia; (V.B.K.); (V.A.K.); (A.A.K.)
- Lilly Hall of Life Sciences, Purdue University, G-225, 915 W State St., West Lafayette, IN 47907, USA
| | - Vasiliy B. Kolesnikov
- X-Bio Institute, Tyumen State University, 10 Semakova Str., 625003 Tyumen, Russia; (V.B.K.); (V.A.K.); (A.A.K.)
- Federal Public Budgetary Scientific Institution, All-Russian Research Institute of Plant Protection, 396030 Voronezh, Russia
| | - Vladimir A. Khaustov
- X-Bio Institute, Tyumen State University, 10 Semakova Str., 625003 Tyumen, Russia; (V.B.K.); (V.A.K.); (A.A.K.)
| | - Alexander A. Khaustov
- X-Bio Institute, Tyumen State University, 10 Semakova Str., 625003 Tyumen, Russia; (V.B.K.); (V.A.K.); (A.A.K.)
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Klimov PB, Kolesnikov VB, Demard EP, Stinson CSA, Merckx J, Duarte MVA, Pedroso LGA, Khaustov AA, Myers-Hansen JL, Wäkers FL, Vangansbeke D. Going Asexual: A Survey of Mites of the Genus Thyreophagus (Acari: Acaridae) Revealing a Large Number of New Parthenogenetic Species in the Holarctic Region. Life (Basel) 2023; 13:2168. [PMID: 38004308 PMCID: PMC10672012 DOI: 10.3390/life13112168] [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: 10/12/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
Mites of the genus Thyreophagus (Acari: Acaridae) are distributed worldwide; they inhabit concealed habitats and include several beneficial and economically important species. However, species identification is difficult because many species are poorly described or delimited and their phoretic stages are unknown or uncorrelated. Furthermore, Thyreophagus is interesting because it includes entirely asexual (parthenogenetic) species. However, among the 34 described species of Thyreophagus, the asexual status is confirmed through laboratory rearing for only two species. Here, we provide detailed descriptions of five new species from North America (four) and Europe (one) based on adults and phoretic heteromorphic deutonymphs. Four of these species were asexual, while one was sexual. For most of these mites, the asexual status was confirmed and phoretic deutonymphs were obtained through rearing in the lab. We show that asexual mites retain seemingly functional copulatory and sperm storage systems, indicating that these lineages have relatively short evolutionary lifespans. One North American species, Thyreophagus ojibwe, was found in association with the native American chestnut Castanea dentata, suggesting a possibility that this mite can be used to control chestnut blight in North America. We also provide a diagnostic key to females, males, and heteromorphic deutonymphs of the Thyreophagus species in the world.
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Affiliation(s)
- Pavel B. Klimov
- Lilly Hall of Life Sciences, Purdue University, G-225, 915 W State St, West Lafayette, IN 47907, USA;
- X-Bio Institute, Tyumen State University, 25 Lenina St. Str., 625003 Tyumen, Russia; (V.B.K.)
| | - Vasiliy B. Kolesnikov
- X-Bio Institute, Tyumen State University, 25 Lenina St. Str., 625003 Tyumen, Russia; (V.B.K.)
- All-Russian Research Institute of Plant Protection, 396030 Voronezh, Russia
| | - Emilie P. Demard
- Citrus Research and Education Center, University of Florida, 700 Experiment Road Station, Lake Alfred, FL 33850, USA
| | | | - Jonas Merckx
- Biobest Sustainable Crop Management, R&D, 2260 Westerlo, Belgium; (J.M.)
- Biodiversity Inventory for Conservation NPO (BINCO), Walmersumstraat 44, 3380 Glabbeek, Belgium
| | | | - Luiz Gustavo A. Pedroso
- Departamento de Zoologia, Universidade Estadual Paulista, Av. 24-A, 1515, Rio Claro 13506-900, SP, Brazil;
| | - Alexander A. Khaustov
- X-Bio Institute, Tyumen State University, 25 Lenina St. Str., 625003 Tyumen, Russia; (V.B.K.)
| | - James Leslie Myers-Hansen
- Lilly Hall of Life Sciences, Purdue University, G-225, 915 W State St, West Lafayette, IN 47907, USA;
| | - Felix L. Wäkers
- Biobest Sustainable Crop Management, R&D, 2260 Westerlo, Belgium; (J.M.)
| | - Dominiek Vangansbeke
- Biobest Sustainable Crop Management, R&D, 2260 Westerlo, Belgium; (J.M.)
- Biodiversity Inventory for Conservation NPO (BINCO), Walmersumstraat 44, 3380 Glabbeek, Belgium
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Rigling D, Prospero S. Cryphonectria parasitica, the causal agent of chestnut blight: invasion history, population biology and disease control. MOLECULAR PLANT PATHOLOGY 2018; 19:7-20. [PMID: 28142223 PMCID: PMC6638123 DOI: 10.1111/mpp.12542] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 12/19/2016] [Accepted: 01/26/2017] [Indexed: 05/25/2023]
Abstract
Chestnut blight, caused by Cryphonectria parasitica, is a devastating disease infecting American and European chestnut trees. The pathogen is native to East Asia and was spread to other continents via infected chestnut plants. This review summarizes the current state of research on this pathogen with a special emphasis on its interaction with a hyperparasitic mycovirus that acts as a biological control agent of chestnut blight. TAXONOMY Cryphonectria parasitica (Murr.) Barr. is a Sordariomycete (ascomycete) fungus in the family Cryphonectriaceae (Order Diaporthales). Closely related species that can also be found on chestnut include Cryphonectria radicalis, Cryphonectria naterciae and Cryphonectria japonica. HOST RANGE Major hosts are species in the genus Castanea (Family Fagaceae), particularly the American chestnut (C. dentata), the European chestnut (C. sativa), the Chinese chestnut (C. mollissima) and the Japanese chestnut (C. crenata). Minor incidental hosts include oaks (Quercus spp.), maples (Acer spp.), European hornbeam (Carpinus betulus) and American chinkapin (Castanea pumila). DISEASE SYMPTOMS Cryphonectria parasitica causes perennial necrotic lesions (so-called cankers) on the bark of stems and branches of susceptible host trees, eventually leading to wilting of the plant part distal to the infection. Chestnut blight cankers are characterized by the presence of mycelial fans and fruiting bodies of the pathogen. Below the canker the tree may react by producing epicormic shoots. Non-lethal, superficial or callusing cankers on susceptible host trees are usually associated with mycovirus-induced hypovirulence. DISEASE CONTROL After the introduction of C. parasitica into a new area, eradication efforts by cutting and burning the infected plants/trees have mostly failed. In Europe, the mycovirus Cryphonectria hypovirus 1 (CHV-1) acts as a successful biological control agent of chestnut blight by causing so-called hypovirulence. CHV-1 infects C. parasitica and reduces its parasitic growth and sporulation capacity. Individual cankers can be therapeutically treated with hypovirus-infected C. parasitica strains. The hypovirus may subsequently spread to untreated cankers and become established in the C. parasitica population. Hypovirulence is present in many chestnut-growing regions of Europe, either resulting naturally or after biological control treatments. In North America, disease management of chestnut blight is mainly focused on breeding with the goal to backcross the Chinese chestnut's blight resistance into the American chestnut genome.
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Affiliation(s)
- Daniel Rigling
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)Birmensdorf8903Switzerland
| | - Simone Prospero
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)Birmensdorf8903Switzerland
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Occurrence and transmission of mycovirus Cryphonectria hypovirus 1 from dejecta of Thyreophagus corticalis (Acari, Acaridae). Fungal Biol 2015; 120:351-7. [PMID: 26895863 DOI: 10.1016/j.funbio.2015.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 10/29/2015] [Accepted: 11/10/2015] [Indexed: 11/20/2022]
Abstract
The natural spread of virus-induced hypovirulence is highly involved in the recovery of blighted chestnut stands and orchards in Italy and in Europe. The potential role of corticolous mites as vectors of hypovirulence in blighted chestnut Castanea sativa (Mill.) stands was pointed out in previous reports. Here, by using RT-PCR, mycovirus Cryphonectria hypovirus (CHV1) was detected in Thyreophagus corticalis mites reared on a hypovirulent strain in monoxenic cultures and in their faecal pellets. Cryphonectria parasitica mycelium derived from mites' dejecta was able to transmit CHV1 to the virulent strain determining its conversion to hypovirulent one. This converted strain induced healing cankers on excised stems, differently from the un-converted virulent strain. Our findings prove the spread of CHV1 by corticolous mites that feed on virus-infected fungus and emphasize their potential role as vectors.
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Vainio EJ, Hantula J. Taxonomy, biogeography and importance of Heterobasidion viruses. Virus Res 2015; 219:2-10. [PMID: 26477938 DOI: 10.1016/j.virusres.2015.10.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 10/08/2015] [Accepted: 10/10/2015] [Indexed: 11/17/2022]
Abstract
The genus Heterobasidion consists of several species of necrotrophic and saprotrophic fungi, and includes some of the most detrimental organisms in boreal conifer forests. These fungi host a widespread and diverse mycovirus community composed of more than 16 species of Partitiviridae, a species of Narnaviridae and one taxonomically unassigned virus related to the Curvularia thermal tolerance virus. These viruses are able to cross species borders, co-infect single host strains and cause phenotypic changes in their hosts. The abundance of viruses increases over time in Heterobasidion infection centers, and they are targeted by fungal RNA interference. Long-term field studies are essential for obtaining a comprehensive view of virus effects in the nature.
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Affiliation(s)
- Eeva J Vainio
- Natural Resources Institute Finland (Luke), Jokiniemenkuja 1, POB 18, 01301 Vantaa, Finland.
| | - Jarkko Hantula
- Natural Resources Institute Finland (Luke), Jokiniemenkuja 1, POB 18, 01301 Vantaa, Finland.
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