Histological comparison of compatible, mesothetic and incompatible reactions between Puccinia graminis tritici and wheat

1981 ◽  
Vol 59 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Verna J. Higgins
Keyword(s):  
Hypersensitive Reaction ◽  
Puccinia Graminis ◽  
Compatible Interaction ◽  
Incompatible Interaction ◽  
Puccinia Graminis Tritici ◽  
Incompatible Reaction

Three races of Puccinia graminis tritici developed by successive mutations to give increased virulence (i.e., incompatible → mesothetic → compatible) on the Sr6 gene for resistance were compared histologically on cv. McMurachy (Sr6 gene) growing at 20.5 °C. The length of the longest hyphae and the size of the lesions remained similar in the three interactions up to 3 days after inoculation and then comparative degrees of growth occurred in the following decreasing order; compatible > mesothetic > incompatible. Necrotic cells in the compatible interaction were infrequent (maximum of 6% of infection sites) and hyphae radiated out from the point of ingress in an unimpeded manner. Although necrosis in the incompatible interaction occurred 1 day in advance of necrosis in the mesothetic reaction, by the 6th day, 98–100% of the infection sites in both systems had necrotic cells. In the mesothetic reaction, hyphae grew beyond the area of necrosis in a high proportion (70% at day 6) of the infection sites whereas the incidence of such growth was much less (8% at day 6) in the incompatible reaction. The role of the hypersensitive reaction in these interactions is discussed.

Increased Lipoxygenase Activity is Involved in the Hypersensitive Response of Wheat Leaf Cells Infected with A virulent Rust Fungi or Treated with Fungal Elicitor

1986 ◽  
Vol 41 (5-6) ◽  
pp. 559-563 ◽  
Author(s):  
Carlos A. Ocampo ◽  
Bruno Moerschbacher ◽  
Hans J. Grambow
Keyword(s):  
Hypersensitive Response ◽  
Hypersensitive Reaction ◽  
Rust Fungi ◽  
Lipoxygenase Activity ◽  
Puccinia Graminis ◽  
Compatible Interaction ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Germ Tubes ◽  
Wheat Rust

The hypersensitive reaction in incompatible wheat-rust interactions is characterized by an increase in lipoxygenase activity detectable as early as 28 h after penetration of the pathogen. In contrast, lipoxygenase activity in the compatible interaction did not increase until the onset of sporulation.Lipoxygenase activity also increased following treatment of wheat leaves with an elicitor fraction from germ tubes of Puccinia graminis tritici.

scholarly journals Compatible and Incompatible Interactions in Wheat Involving the Bt-10 Gene for Resistance to Tilletia tritici, the Common Bunt Pathogen

2007 ◽  
Vol 97 (11) ◽  
pp. 1397-1405 ◽  
Author(s):  
Denis A. Gaudet ◽  
Zhen-Xiang Lu ◽  
Frances Leggett ◽  
Bryan Puchalski ◽  
André Laroche
Keyword(s):  
Compatible Interaction ◽  
Incompatible Interaction ◽  
Common Bunt ◽  
Tilletia Tritici ◽  
Pathogen Invasion ◽  
Reaction Zones ◽  
The Common ◽  
Wheat Lines ◽  
Compatible Interactions ◽  
Incompatible Interactions

The infection of wheat lines Neepawa (susceptible), and its sib BW553 that is nearly isogenic for the Bt-10 resistance gene by differentially virulent races T1 and T27 of common bunt (Tilletia tritici), was followed for 21 days following seeding (dfs) using fluorescence and confocal microscopy. Spore germination was nonsynchronous and all spore stages including germination were observed 5 to 21 dfs. Initial host perception of pathogen invasion, based on autofluorescence in epidermal cells adjacent to the appressoria, was similar in both compatible and incompatible interactions, and occurred as early as 5 to 6 dfs. The total number of sites on a 1-cm segment of coleoptile adjacent to the seed that exhibited autofluorescence was similar in both the compatible and incompatible interactions and rose to a maximum of 35 to 40 per 1 cm length of coleoptile following 17 dfs, although new infection events were observed as late as 21 dfs. In the compatible interaction, the autofluorescence became more diffuse 10 to 12 dfs, emanating in all directions in association with fungal spread. In the incompatible interaction, autofluorescence remained restricted to a small area surrounding the penetration site. Two different reaction zones that extended further in tissues surrounding the penetration point in the incompatible interaction compared with the compatible interaction were identified. The accumulation of callose around invading fungal hyphae was observed during both the compatible and incompatible interactions from 8 to 21 dfs. While callose accumulation was more extensive and widespread in the incompatible interaction, it was clearly present in compatible interactions, particularly in treatments involving BW553. These results were confirmed by expression of callose synthase transcripts that were more abundant in BW553 than in Neepawa and were upregulated during pathogen infection in both compatible and incompatible interactions.

Epidemiology of Puccinia graminis f.sp. tritici-Ug99 in the Rift Valley “Flyway” from Uganda-Kenya to Yemen

2012 ◽  
Vol 13 (1) ◽  
pp. 31 ◽  
Author(s):  
Subrahmaniam Nagarajan ◽  
Hans J. Kogel ◽  
Jan C. Zadoks
Keyword(s):  
Rift Valley ◽  
Puccinia Graminis ◽  
Puccinia Graminis Tritici ◽  
Wheat Cultivation

Dispersal of a new virulence of Puccinia graminis tritici (Pgt)-Ug99 from Uganda-Kenya to Yemen, over >1000 km, happened in four years. Geo-agro-ecology of wheat cultivation and the epidemiology of Pgt indicate that the Rift Valley is a natural conduit “flyway.” The widely prevalent “green bridges” favor survival and spread of Pgt. This part of the Rift Valley is one single epidemiological zone, and the annual Pgt build-up is from the endogenous inoculum. Accepted for publication 18 October 2012. Published 14 November 2012.

scholarly journals A Third Factor for Resistance to Puccinia graminis Tritici

Nature ◽  
1945 ◽  
Vol 155 (3929) ◽  
pp. 205-205
Author(s):  
I. A. WATSON ◽  
W. L. WATERHOUSE
Keyword(s):  
Puccinia Graminis ◽  
Puccinia Graminis Tritici

STUDIES ON THE NATURE OF RUST RESISTANCE IN WHEAT: VI. EFFECT OF HYDROGEN ION CONCENTRATION, PHENOLIC COMPOUNDS, AND HOST EXTRACTS ON THE GERMINATION OF UREDINIOSPORES OF PUCCINIA GRAMINIS TRITICI, FORM 21

1934 ◽  
Vol 11 (6) ◽  
pp. 667-686 ◽  
Author(s):  
J. Ansel Anderson
Keyword(s):  
Phenolic Compounds ◽  
Rust Resistance ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Puccinia Graminis ◽  
Inhibitory Effects ◽  
Hydrogen Ion Concentration ◽  
Puccinia Graminis Tritici ◽  
The Press ◽  
Germ Tubes

Urediniospores of Puccinia graminis tritici, form 21, were sown on buffer solutions covering the range from pH 3 to pH 8. Maximum germination was obtained between pH 5.8 and 6.5, with indications that if the point of maximum germination could be determined with precision it would be found to lie in the neighborhood of pH 6.2.The effect of buffered and unbuffered solutions of pure phenolic compounds on the germination of urediniospores was studied. Greater inhibition was obtained with unbuffered solutions owing to the additional effect of hydrogen ion concentration. In buffered solutions, at pH 6.0, germination was prevented by 45 p.p.m. of hydroquinone, 125 of o-cresol, 180 of anisic acid, 250 of benzoic acid, 340 of catechol, 400 of guaiacol and 600 of phenol. A number of other compounds were also studied. The inhibitory effects of compounds, of which the bactericidal effects are known, are fairly closely related to their bactericidal efficiency.Investigations were made of the inhibitory effects on spore germination and the growth of germ tubes, of aqueous dilutions of 15, 10, 5 and 2.5% of the press-juice of Vernal, Khapli, Marquis and Little Club wheats. Statistical treatment of the data accumulated in ten series of determinations, in which a total of 160,000 spores was counted, showed that significant differences occurred between varieties and that variations in the total solid content and hydrogen ion concentration of the press-juice had no consistent effect upon the results. Although the results were not entirely clear-cut, it is concluded that the varieties fall in the following order with respect to increasing inhibitory effect of their extracts: Vernal, Marquis, Khapli and Little Club. Since Vernal and Khapli are resistant to form 21 whereas Marquis and Little Club are susceptible, the results fail to show any relationship between the effects of host extracts on the germination of urediniospores, or on the growth of germ tubes, and the rust resistance of the variety.

PHYSIOLOGIC SPECIALIZATION OF OAT STEM RUST IN CANADA

1944 ◽  
Vol 22c (5) ◽  
pp. 201-216 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson
Keyword(s):  
Stem Rust ◽  
Wide Distribution ◽  
Puccinia Graminis ◽  
Characteristic Type ◽  
Influence Of Temperature ◽  
Physiologic Specialization ◽  
Influence Of Temperature On ◽  
Physiologic Races

An account is given of the results of studies on the physiologic specialization of Puccinia graminis Avenae Erikss. and Henn. in Canada since the inception of the work. Twelve physiologic races were identified from 2586 isolates studied during the period 1921 to 1943. The annual surveys of the prevalence of physiologic races during this period show that each year races 1, 2, and 5 have comprised the bulk of the oat stem rust in all parts of Canada. The predominance of these races has been greatest in the three Prairie Provinces, where barberry is virtually non-existent. In regions where barberry is present, other races of greater range of pathogenicity have been found more frequently than in these three provinces. The occurrence of such races, however, was sporadic until 1943, in which year races 8, 10, and 11 attained a wide distribution, apparently traceable to wind-borne urediospores from the south. There is evidence that the strains of these races present in 1943 remain in the uredial stage for much longer periods than do strains of the same races collected in previous years—a fact that may have favoured their spread in this year.The role of barberry in the origination of generally virulent physiologic races is discussed. The possibility that such races may also originate by mutation is suggested by spontaneous pathogenic changes that occurred, in the greenhouse, in a culture of race 3 that gave rise to several cultures of race 7.The effect of environment on the identification of physiologic races is demonstrated by the seasonal influences on the reaction of the variety Sevnothree to races 1 and 11. On this variety the characteristic type 1 is frequently replaced, in summer, by type x.Experiments on the influence of temperature on the reaction of adult oat plants to stem rust showed that a constant temperature of about 80° F. does not appreciably affect the reaction of White Tartar and Richland, or of other varieties with the same type of resistance, but is capable of breaking down the resistance of certain varieties derived from the crosses Hajira × Joanette, Hajira × Banner, and Victoria × (Hajira × Banner).

Sign in / Sign up

Export Citation Format

Share Document