Influence of weight of seed on hyphal growth of the take-all pathogen, Gaeumannomyces graminis var. tritici, in wheat roots grown in sand culture

1987 ◽  
Vol 27 (4) ◽  
pp. 559 ◽  
Author(s):  
L Penrose
Keyword(s):  
Hyphal Growth ◽  
Gaeumannomyces Graminis ◽  
Sand Culture ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Seminal Roots ◽  
Linear Manner ◽  
Inner Cortex ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Complex Manner

This study examined extent of hyphal growth of Gaeumannomyces graminis var. tritici (Ggt) in seminal roots of wheat seedlings grown from seed of varying weight (12-60 mg). Hyphal invasion, measured microscopically in the inner cortex, endodermis and stele of root sections and in the early formation of stelar lesions, was found to be influenced in a complex manner by weight of seed. As weight of seed was increased, invasion of the inner cortex decreased linearly while invasion of stelar tissue varied in a non linear manner. These findings show that weight of seed must be considered when comparing levels of infection in seedlings of different cultivars of wheat.

Colonization of lateral, seminal and adventitious roots of wheat by the take-all fungus, Gaeumannomyces graminis var. tritici

1980 ◽  
Vol 94 (2) ◽  
pp. 325-329 ◽  
Author(s):  
C. A. Gilligan
Keyword(s):  
Adventitious Roots ◽  
Lateral Roots ◽  
Initial Period ◽  
Hyphal Growth ◽  
Gaeumannomyces Graminis ◽  
Rate Of Growth ◽  
Direct Inoculation ◽  
Seminal Roots ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

SummaryProgressive colonization of adventitious, seminal and lateral roots of wheat by Gaeumannomyces graminis var. triticiwas monitored for 18 days after direct inoculation of roots. Adventitious roots supported greater colonization by superficial runner hyphae above and below inoculation sites than did seminal roots due to more rapid establishment of colonization. Subsequent rates of superficial runner hyphal growth along the two types of root were not significantly different. In contrast with seminal and lateral roots, adventitious roots did not show any dark stelar discoloration during the period of observation. Both the rate of growth of superficial runner hyphae and of advance of dark stelar discoloration were substantially slower on lateral roots than on seminal roots. After an initial period of equal growth above and below inoculation sites, superficial runner hyphae grew more slowly below than above these sites on all three types of root.

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.

scholarly journals Effect of Wheat Roots Infected with the Pathogenic Fungus Gaeumannomyces graminis var. tritici on Gene Expression of the Biocontrol Bacterium Pseudomonas fluorescens Pf29Arp

2009 ◽  
Vol 22 (12) ◽  
pp. 1611-1623 ◽  
Author(s):  
Matthieu Barret ◽  
Pascale Frey-Klett ◽  
Anne-Yvonne Guillerm-Erckelboudt ◽  
Morgane Boutin ◽  
Gregory Guernec ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pseudomonas Fluorescens ◽  
Pathogenic Fungus ◽  
Pathogenic Fungi ◽  
Gaeumannomyces Graminis ◽  
Type Vi Secretion System ◽  
Gene Encoding ◽  
Wheat Roots ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Biocontrol Bacterium

Traits contributing to the competence of biocontrol bacteria to colonize plant roots are often induced in the rhizosphere in response to plant components. These interactions have been studied using the two partners in gnotobiotic systems. However, in nature, beneficial or pathogenic fungi often colonize roots. Influence of these plant–fungus interactions on bacterial behavior remains to be investigated. Here, we have examined the influence of colonization of wheat roots by the take-all fungus Gaeumannomyces graminis var. tritici on gene expression of the biocontrol bacterium Pseudomonas fluorescens Pf29Arp. Bacteria were inoculated onto healthy, early G. graminis var. tritici-colonized and necrotic roots and transcriptomes were compared by shotgun DNA microarray. Pf29Arp decreased disease severity when inoculated before the onset of necrosis. Necrotic roots exerted a broader effect on gene expression compared with early G. graminis var. tritici-colonized and healthy roots. A gene encoding a putative type VI secretion system effector was only induced in necrotic conditions. A common pool of Pf29Arp genes differentially expressed on G. graminis var. tritici-colonized roots was related to carbon metabolism and oxidative stress, with a highest fold-change with necrosis. Overall, the data showed that the association of the pathogenic fungus with the roots strongly altered Pf29Arp adaptation with differences between early and late G. graminis var. tritici infection steps.

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.

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

1988 ◽  
Vol 39 (4) ◽  
pp. 541 ◽  
Author(s):  
RF Brennan
Keyword(s):  
Phosphorus Deficiency ◽  
Root Systems ◽  
Gaeumannomyces Graminis ◽  
Nodal Roots ◽  
Nodal Root ◽  
Seminal Roots ◽  
Phosphorus Status ◽  
Gaeumannomyces Graminis Var Tritici ◽  
P Supply ◽  
Take All

Wheat was grown in a slightly acidic grey sand at six levels of phosphorus, in the presence or absence of take-all inoculum in a glasshouse experiment. The incidence and severity of take-all was related to the phosphorus supply and the phosphorus status of wheat.Plants grown without P were more severely infected by take-all than those grown at adequate levels of phosphorus. The percentage of both nodal and seminal roots infected by take-all declined as the level of P was increased. The percentage of seminal roots infected was reduced from 35% to 13.7% by increasing the supply of phosphorus from levels severely deficient to those adequate for plant growth. Infection in nodal roots was reduced from 24% to 2.3% as the P supply increased. In both the seminal and nodal root systems, increasing the P supply decreased the length of proximal lesions (closest to seed) and increased the length of root between the crown and the proximal lesions.

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