Morphology and host range of<i>Polymyxa graminis, Polymyxa betae,</i>and<i>Ligniera pilorum</i>from Ontario and some other areas

Barr, D. J. S.

doi:10.1080/07060667909501468

Cited by 75 publications

(46 citation statements)

References 13 publications

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“…nasturtii is specific for watercress (Tomlinson 1958). Host-specialization was the primary basis for describing P. betae as a species distinct from P. graminis (Barr 1979;Keskin 1964). Although the two species are morphologically and karyotypically (Braselton 1988) identical, the first molecular genetic analysis supports their distinction (Mutasa et al 1993).…”

Section: Viruses Transmitted By Plasmodiophoridsmentioning

confidence: 97%

“…They survive from crop to crop as resting spores that produce zoospores and infect the host. The plasmodiophorids have bi-flagellate, heterokont zoospores and form cystosori consisting of single-celled resting spores formed by division of the thallus (Tomlinson 1958;Barr 1979). Plasmodiophoretransmitted viruses are mostly positive strand RNA viruses.…”

Section: Fungi Transmitting Plant Virusesmentioning

confidence: 99%

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The Fungal Transmitted Viruses

2008

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Section: Viruses Transmitted By Plasmodiophoridsmentioning

confidence: 97%

Section: Fungi Transmitting Plant Virusesmentioning

confidence: 99%

The Fungal Transmitted Viruses

2008

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“…and Spongospora subterranea (e.g. Barr, 1968). In an important field study which should provide a model for further work, Hampton & Bucholtz (1962) found evidence that crop-specific strains were selected from a population of Pythium graminicola when different graminaceous crops were grown repeatedly.…”

Section: Crop-specific Soil-borne Pathogensmentioning

confidence: 99%

Ecological implications of recognition events in the pre‐infection stages of root pathogens

Deacon

1996

New Phytologist

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SUMMARYHost-specificity and recognition by root-infecting pathogens are reviewed, with emphasis on fungi but drawing parallels with other root parasites, synnbionts and rhizosphere micro-organisms. Two major levels of specificity are identified; family-specific parasitism, exemplified by many parasites that characteristically infect Gramineae, and the possibly recent segregation of pathogen species into crop-specific strains. In both of these cases there are examples w^here host-specificity is paralleled by host-recognition in the pre-infection stages, including hostspecific triggering of propagule germination. The pre-infection sequence of zoosporic pathogens (Pythium, Phyiophthora, Aphanomyces spp.) is reviewed. These fungi seem to have both general (low-affinity) and hostspecific (high-affinity) receptor-based recognition systems for chemotaxis to root difFusates and for induction of encystment by host surface coniponents, Zoospores orientate (dock) during encystment, and the cysts germinate from a fixed point, whereas the non-motiie spores of at least some root parasites (e.g. Idriella bolleyi) can germinate from any point, which is infiuenced by the host.The possession of both general and host-specific recognition systems by a parasite could enable it to exploit rhizosphere niches or to invade compromised plants in the absence of preferred hosts. Evidence from graminicolous (family-specific) Pythium spp. suggests that host-specific recognition is quantitative rather than absolute but, when compounded over successive cycles of infection, is a powerful selective mechanisna.

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“…O SBWMV apresenta genoma de RNA bipartido encapsulado em partículas alongadas retilíneas, de fita simples e senso positivo (Shirako, 1998). A transmissão do vírus ocorre pela colonização dos pêlos radiculares de plantas através dos zoosporos virulíferos de P. graminis, considerado um parasita obrigatório de raízes de gramíneas (Barr, 1979) que pode persistir por longos períodos em raízes em decomposição ou no solo (Adams, 1991). Os sintomas da virose variam de mosaico verde a mosaico amarelo, ocorrendo mais freqüentemente em plantas com desenvolvimento em áreas mais baixas, especialmente durante extensos períodos de frio e alta umidade do solo (Larsen et al, 1985).…”

Section: Introductionunclassified

Incidência e índice de doença do mosaico do trigo em cereais de inverno e em gramíneas de verão, associados ao Polymyxa graminis

2002

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Incidence and disease index of Soil-borne wheat mosaic virus on winter cereals and summer grasses associated with the fungus Polymyxa graminisThe Soil-borne wheat mosaic virus (SBWMV) is transmitted by the fungus Polymyxa graminis. To evaluate the incidence and the disease index (DI%) and the presence of the vector in the root system, an experiment was carried out using: oat (Avena strigosa and A. sativa), barley (Hordeum vulgare), triticale (Triticum secale), wheat (Triticum aestivum), Lilium multiforum, mayze (Zea mays), sorghum (Sorghum bicolor), Pannisetum americanum, Digitaria sp. and Brachiaria sp. The experiment was conducted during two sowing periods. Incidence was calculated based on the percentage of the symptomatic plants and grades (0-5) were given INTRODUÇÃOO trigo (Triticum aestivum L.) é um dos cultivos mais afetados por doenças causadas por fungos, bactérias e vírus (Mehta, 1978). Entre as doenças de importância para a cultura, está a virose causada pelo vírus do mosaico do trigo (Soilborne wheat mosaic vírus, SBWMV) gênero Furovirus (Campbell, 1996), que tem como vetor o fungo Polymyxa graminis Ledingham (Campbell, 1996). O SBWMV apresenta genoma de RNA bipartido encapsulado em partículas alongadas retilíneas, de fita simples e senso positivo (Shirako, 1998). A transmissão do vírus ocorre pela colonização dos pêlos radiculares de plantas através dos zoosporos virulíferos de P. graminis, considerado um parasita obrigatório de raízes de gramíneas (Barr, 1979) que pode persistir por longos períodos em raízes em decomposição ou no solo (Adams, 1991). Os sintomas da virose variam de mosaico verde a mosaico amarelo, ocorrendo mais freqüentemente em plantas com desenvolvimento em áreas mais baixas, especialmente durante extensos períodos de frio e alta umidade do solo (Larsen et al., 1985).Os fatores que influenciam a transmissão do vírus são microscópio luminoso, atribuindo-se níveis de infestação pela quantidade de grupos de esporos de resistência de P. graminis. Em espécies de aveia, não foram observados sintomas e esporos de resistência do vetor. Na cultura da cevada, não foram observados sintomas, mas sim esporos de resistência no sistema radicular. Para o triticale e o trigo, na primeira época de plantio, a incidência e ID (%) foram mais elevados quando comparados à segunda época. Observou-se uma relação direta entre o ID (%) e a quantidade de esporos de resistência. Nas gramíneas de verão, não foram observados sintomas de SBWMV nem esporos de resistência no sistema radicular. Palavras-chave adicionais: SBWMV, Furovirus, esporos de resistência, virose.to determine the DI (%). Root segments were collected, then stained with solution of cotton blue-lactofenol and visualized in optical microscope. The quantity of resting spores groups was rated. No symptoms were observed on oat species, however, the presence of resting spores in moderate quantities was observed on barley. The incidence and DI (%) for the triticale and wheat in the first sowing period were higher than in the second one. A di...

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Morphology and host range ofPolymyxa graminis, Polymyxa betae,andLigniera pilorumfrom Ontario and some other areas

Cited by 75 publications

References 13 publications

The Fungal Transmitted Viruses

The Fungal Transmitted Viruses

Ecological implications of recognition events in the pre‐infection stages of root pathogens

Incidência e índice de doença do mosaico do trigo em cereais de inverno e em gramíneas de verão, associados ao Polymyxa graminis

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