A volatile factor inducing transmissible lysis in Gaeumannomyces graminis (Sacc.) Arx and Olivier var. tritici Walker

1975 ◽  
Vol 21 (3) ◽  
pp. 293-300 ◽  
Author(s):  
K. Sivasithamparam ◽  
M. Stukely ◽  
C. A. Parker
Keyword(s):  
Ultraviolet Light ◽  
Uv Light ◽  
Virulent Strain ◽  
Water Extract ◽  
Gaeumannomyces Graminis ◽  
Heat Stable ◽  
History Of ◽  
Sublethal Doses ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

Filtered water extract of Gabalong soil with a recent history of take-all in wheat caused lytic plaques to form in agar cultures of a virulent strain of Gaeumannomyces graminis var. tritici. The plaques resembled those produced by Bdellovibrio on plates seeded with bacteria. However, there was no evidence of the presence of bacteria, viruses, or mycoplasmas.The lytic factor was transmissible in culture filtrates to fresh subcultures of the fungus. Exposure of young healthy colonies to sublethal doses of ultraviolet light also induced transmissible lysis. The lytic factor was heat-stable, passed through a 25-nm filter, and was not affected by nuclease (enzymes) or severe irradiation with UV light. It also induced lysis in several other strains of G. graminis. Lysis was always preceded by a growth-stimulatory effect on the fungus.The lytic factor was active as a volatile chemical which induced transmissible lysis and continued to be formed, apparently as a self-perpetuating agent, in lysing cultures of the fungus.

Biological suppression of the saprophytic growth of Gaeumannomyces graminis var. tritici in soil

1987 ◽  
Vol 33 (6) ◽  
pp. 515-519 ◽  
Author(s):  
A. Simon ◽  
K. Sivasithamparam ◽  
G. C. MacNish
Keyword(s):  
Disease Severity ◽  
Gaeumannomyces Graminis ◽  
Seminal Root ◽  
Adjacent Area ◽  
Wheat Seedlings ◽  
Γ Radiation ◽  
Filter Membrane ◽  
History Of ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

The biological suppression of the saprophytic growth of Gaeumannomyces graminis var. tritici in soil in the absence of host roots appeared to be related to suppression of take-all disease of wheat seedlings. When soil collected from a plot which in 1984 and 1985 had grown wheat continuously for 7 and 8 years, respectively, was added at a level of 1% (w/w) to the same soil treated by γ-radiation, saprophytic growth of pigmented hyphae of G. graminis var. tritici on a filter membrane in a soil sandwich was suppressed relative to that occurring in irradiated soil. A soil of the same type from an adjacent area with a history of cereal–pasture alternate rotation did not significantly suppress saprophytic growth of G. graminis var. tritici. Biological suppression of disease of wheat caused by G. graminis var. tritici was tested in a pot bioassay by adding the same two soils, collected in 1985, at a level of 1% (w/w) to fumigated sand infested with oat kernels axenically colonized by the pathogen. Disease severity, measured as the percentage of the seminal root axes with discoloured stele, was reduced by 42 and 6% with the addition of continuous wheat and cereal–pasture rotation soils, respectively, to infested sand, compared with disease severity in unamended, infested sand alone.

scholarly journals Diversity, Virulence, and 2,4-Diacetylphloroglucinol Sensitivity of Gaeumannomyces graminis var. tritici Isolates from Washington State

2009 ◽  
Vol 99 (5) ◽  
pp. 472-479 ◽  
Author(s):  
Youn-Sig Kwak ◽  
Peter A. H. M. Bakker ◽  
Debora C. M. Glandorf ◽  
Jennifer T. Rice ◽  
Timothy C. Paulitz ◽  
...  
Keyword(s):  
Geographical Origin ◽  
Geographic Origin ◽  
Washington State ◽  
Gaeumannomyces Graminis ◽  
Growing Seasons ◽  
History Of ◽  
Pathogenicity Tests ◽  
Polymerase Chain ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

We determined whether isolates of the take-all pathogen Gaeumannomyces graminis var. tritici become less sensitive to 2,4-diacetylphloroglucinol (2,4-DAPG) during wheat monoculture as a result of exposure to the antibiotic over multiple growing seasons. Isolates of G. graminis var. tritici were baited from roots of native grasses collected from noncropped fields and from roots of wheat from fields with different cropping histories near Lind, Ritzville, Pullman, and Almota, WA. Isolates were characterized by using morphological traits, G. graminis variety-specific polymerase chain reaction and pathogenicity tests. The sensitivity of G. graminis var. tritici isolates to 2,4-DAPG was determined by measuring radial growth of each isolate. The 90% effective dose value was 3.1 to 4.4 μg ml–1 for 2,4-DAPG-sensitive isolates, 4.5 to 6.1 μg ml–1 for moderately sensitive isolates, and 6.2 to 11.1 μg ml–1 for less sensitive isolates. Sensitivity of G. graminis var. tritici isolates to 2,4-DAPG was normally distributed in all fields and was not correlated with geographic origin or cropping history of the field. There was no correlation between virulence on wheat and geographical origin, or virulence and sensitivity to 2,4-DAPG. These results indicate that G. graminis var. tritici does not become less sensitive to 2,4-DAPG during extended wheat monoculture.

scholarly journals Isolation, Characterization, and Sensitivity to 2,4-Diacetylphloroglucinol of Isolates of Phialophora spp. from Washington Wheat Fields

2010 ◽  
Vol 100 (5) ◽  
pp. 404-414 ◽  
Author(s):  
Youn-Sig Kwak ◽  
Peter A. H. M. Bakker ◽  
Debora C. M. Glandorf ◽  
Jennifer T. Rice ◽  
Timothy C. Paulitz ◽  
...  
Keyword(s):  
Sequence Comparison ◽  
Phylogenetic Trees ◽  
Washington State ◽  
Gaeumannomyces Graminis ◽  
Wild Oat ◽  
Genetic Characteristics ◽  
Oat Cultivars ◽  
Eastern Washington ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

Dark pigmented fungi of the Gaeumannomyces–Phialophora complex were isolated from the roots of wheat grown in fields in eastern Washington State. These fungi were identified as Phialophora spp. on the basis of morphological and genetic characteristics. The isolates produced lobed hyphopodia on wheat coleoptiles, phialides, and hyaline phialospores. Sequence comparison of internal transcribed spacer regions indicated that the Phialophora isolates were clearly separated from other Gaeumannomyces spp. Primers AV1 and AV3 amplified 1.3-kb portions of an avenacinase-like gene in the Phialophora isolates. Phylogenetic trees of the avenacinase-like gene in the Phialophora spp. also clearly separated them from other Gaeumannomyces spp. The Phialophora isolates were moderately virulent on wheat and barley and produced confined black lesions on the roots of wild oat and two oat cultivars. Among isolates tested for their sensitivity to 2,4-diacetylphloroglucinol (2,4-DAPG), the 90% effective dose values were 11.9 to 48.2 μg ml–1. A representative Phialophora isolate reduced the severity of take-all on wheat caused by two different isolates of Gaeumannomyces graminis var. tritici. To our knowledge, this study provides the first report of an avenacinase-like gene in Phialophora spp. and demonstrated that the fungus is significantly less sensitive to 2,4-DAPG than G. graminis var. tritici.

Gaeumannomyces graminis var. tritici. [Descriptions of Fungi and Bacteria].

1973 ◽  
Author(s):  
J. Walker
Keyword(s):  
Geographical Distribution ◽  
Root Hairs ◽  
Seed Transmission ◽  
Gaeumannomyces Graminis ◽  
Root Infection ◽  
Root Death ◽  
Meristematic Region ◽  
Germ Tubes ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

Abstract A description is provided for Gaeumannomyces graminis var. tritici. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Gramineae, especially Triticum, Hordeum, Secale, Agropyron and several other grass genera and, more rarely, Sorghum and Zea; also recorded from the roots of plants in other families. DISEASE: Take-all of cereals and grasses (also referred to as deadheads or whiteheads, pietin and pied noir (France), Schwarzbeinigkeit and Ophiobolus Fusskrankheit (Germany), Ophiobolusvoetziekt (Netherlands) and others). Root infection is favoured by soil temperature from 12-20°C (Butler, 1961). Ascospore germ tubes penetrate root hairs and the epidermis in the meristematic region (Weste, 1972) leading to plugging of xylem and root death. GEOGRAPHICAL DISTRIBUTION: (CMI Map 334, ed. 3, 1972). Widespread, especially in temperate zones. Africa; Asia (India, Iran, Japan, USSR): Australasia and Oceania; Europe; North America (Canada, USA); South America (Argentina, Brazil, Chile, Colombia, Uruguay). TRANSMISSION: In soil on infected organic fragments, as runner hyphae on roots of cereals and grasses and, under special conditions, by ascospores. Seed transmission very doubtful (47, 3058).

Effect of copper deficiency in wheat on the infection of roots by Gaeumannomyces graminis var. tritici

1984 ◽  
Vol 35 (6) ◽  
pp. 735 ◽  
Author(s):  
MJ Wood ◽  
AD Robson
Keyword(s):  
Plant Growth ◽  
Copper Deficiency ◽  
Gaeumannomyces Graminis ◽  
Fresh Weight ◽  
Nodal Roots ◽  
Copper Status ◽  
Seminal Roots ◽  
Effect Of Copper ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

Wheat was grown in a soil at five levels of copper (ranging from levels deficient, to those luxurious, for plant growth), in the presence or absence of introduced take-all inoculum (oat kernels colonized by Gaeumannomyces graminis var. tritica). The incidence and severity of take-all were related to the copper supply and hence the copper status of the wheat. Plants grown without applied copper were more severely infected by take-all than were those grown with an adequate or luxurious supply of copper. The number of lesions per gram fresh weight of roots was reduced from 6.5 to 2.4 by increasing the copper supply from that severely deficient, to that adequate for plant growth. In seminal roots, increasing the copper supply from levels severely deficient to those adequate or luxurious for plant growth, decreased the length of proximal lesions (those closest to the seed). By contrast, in nodal roots, a similar increase in copper supply had no effect on the length of proximal lesions, but increased the length of uninfected root between the crown and proximal lesions. In both seminal and nodal roots, copper supply did not affect the intensity of lesions.

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