Sterols of healthy and rust-infected primary leaves of wheat and of non-germinated and germinated uredospores of wheat stem rust

1972 ◽  
Vol 50 (1) ◽  
pp. 185-190 ◽  
Author(s):  
R. Nowak ◽  
W. K. Kim ◽  
R. Rohringer
Keyword(s):  
Thin Layer ◽  
Stem Rust ◽  
Total Sterol ◽  
Sterol Content ◽  
Wheat Stem Rust ◽  
Resistant Lines ◽  
Wheat Leaves

Sterols extracted from healthy and rust-infected primary leaves of wheat or from non-germinated and germinated uredospores of stem rust were analyzed by thin-layer, column, and gas–liquid chromatography.Wheat leaves of susceptible and resistant lines contained cholesterol, campesterol, stigmasterol, β-sitosterol, and an unknown sterol that accounted for 75% to 80% of total sterol content. A further sterol, stigmast-7-enol, occurred in all rust-infected leaves and in 1 of 11 samples of healthy leaves. Sterol levels were not related to susceptibility or resistance. The level of stigmast-7-enol in infected leaves appeared to be correlated with the amount of fungal mass in the host.Uredospores of stem rust contained trace amounts of an unknown sterol, cholesterol, and either ergost-7-enol or stigmasterol, and larger amounts of stigmast-7-enol. After germination, the level of cholesterol increased, especially in differentiating uredosporelings. The level of stigmast-7-enol tended to decrease after germination.Sterol fractions from wheat leaves (healthy and rust-infected) and from stem rust uredospores (non-germinated and germinated) were not phytotoxic. They did not inhibit rust development in susceptible leaves nor did they promote it in resistant leaves.

A Fungal Elicitor of the Resistance Response in Wheat

1985 ◽  
Vol 40 (9-10) ◽  
pp. 743-744 ◽  
Author(s):  
Karl-Heinz Kogel ◽  
Birgit Heck ◽  
Gerd Kogel ◽  
Bruno Moerschbacher ◽  
Hans-Joachim Reisener
Keyword(s):  
Stem Rust ◽  
Active Compound ◽  
Germ Tube ◽  
Phenylpropanoid Pathway ◽  
Metabolic Changes ◽  
Fungal Elicitor ◽  
Wheat Stem Rust ◽  
Mesophyll Cells ◽  
Resistance Response ◽  
Wheat Leaves

Abstract An elicitor of the lignification response in wheat leaves was isolated from the germ-tube walls of wheat stem rust. The active compound causes metabolic changes typically correlated with the resistance response, i.e. the formation of lignin or lignin-like polymers in affected epidermal and mesophyll cells and the increased activities of enzymes involved in the phenylpropanoid-pathway.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: X. THE METABOLISM OF INDOLEACETIC ACID-1-C14 BY WHEAT AND OAT COLEOPTILE SECTIONS, UNINFECTED AND RUSTED WHEAT LEAVES AND UREDOSPORES OF WHEAT STEM RUST

1962 ◽  
Vol 40 (3) ◽  
pp. 511-521 ◽  
Author(s):  
B. I. Sahai Srivastava ◽  
Michael Shaw ◽  
R. J. Woods
Keyword(s):  
Stem Rust ◽  
Indoleacetic Acid ◽  
Water Soluble ◽  
Wheat Stem Rust ◽  
Resistant Species ◽  
Metabolic Products ◽  
Soluble Compound ◽  
Wheat Leaves ◽  
Insoluble Compounds ◽  
Host Parasite

Coleoptiles of Little Club wheat and Brighton oats, uninfected and rusted leaves of Little Club and Khapli wheats and uredospores of stem rust were incubated with 10 or 100 parts per million of indoleacetate-C14OOK (IAA) in distilled water in darkness. The metabolic products formed were extracted by boiling the incubation medium. This was then partitioned with ether and the aqueous and ether fractions were analyzed by paper chromatography. In the coleoptiles and uninfected and rusted wheat leaves 8–14 different Ehrlich- or Salkowski-positive radioactive products of IAA metabolism were detected. These were not found when the plant material was incubated with water alone. One ether-soluble compound, and four ether-insoluble compounds from wheat coleoptiles had ultraviolet spectra of the indole type and were found to be active in the Avena straight growth test. IAA and its ether-soluble products disappeared more rapidly from uninfected than from rust-infected Little Club wheat leaves. Four water-soluble, radioactive products were found in uninfected leaves but only two in rusted leaves. A substance tentatively identified as indolecarboxylic acid (ICA) was not found in Little Club wheat leaves until 16 days after rust infection, but was present in both uninfected and infected leaves of the resistant species, Khapli. Uredospores apparently converted IAA only to nonradioactive decarboxylation products, tentatively identified as ICA and indolealdehyde. The results are discussed and attention is drawn to the importance of ether-insoluble products of IAA metabolism.

AN ELECTRON MICROSCOPE STUDY OF INTRAVACUOLAR BODIES IN THE UREDIA OF WHEAT STEM RUST AND IN HYPHAE OF OTHER FUNGI

1967 ◽  
Vol 45 (9) ◽  
pp. 1473-1478 ◽  
Author(s):  
P. L. Thomas ◽  
P. K. Isaac
Keyword(s):  
Electron Microscope ◽  
Internal Structure ◽  
Stem Rust ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Osmium Tetroxide ◽  
Wheat Stem Rust ◽  
Wheat Leaves

An electron microscope study of plant and fungal specimens fixed in a mixture of glutaraldehyde and acrolein followed by osmium tetroxide showed intravacuolar bodies with an intricate internal structure ranging from myelin-like membranes to a system of tubules. The bodies were commonly found in the developing uredia of stem rust infected wheat leaves and in the hyphae of several species of fungi. The origin and nature of the bodies is discussed.

scholarly journals Resistance to Puccinia graminis f. sp. avenae in Barley Is Associated with the Rpg5 Locus

2015 ◽  
Vol 105 (4) ◽  
pp. 490-494 ◽  
Author(s):  
Peter Dracatos ◽  
Davinder Singh ◽  
Tom Fetch ◽  
Robert Park
Keyword(s):  
Stem Rust ◽  
Recombinant Inbred ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Formae Speciales ◽  
Major Threat ◽  
Resistant Lines ◽  
Rust Pathogen ◽  
Ril Population ◽  
Parental Lines

In barley, gene Rpg5 was first identified for providing resistance to the rye stem rust pathogen (Puccinia graminis f. sp. secalis). A subsequent study determined that Rpg5 is required for rpg4-mediated resistance to the wheat stem rust pathogen (P. graminis f. sp. tritici) including pathotype TTKSK (“Ug99”), which poses a major threat to global wheat and barley production. Based on the effectiveness of Rpg5 against P. graminis f. sp. tritici and P. graminis f. sp. secalis, we assessed whether it also conferred resistance to the oat stem rust pathogen (P. graminis f. sp. avenae). A barley F8 recombinant inbred line (RIL) population was produced by crossing ‘Q21861’ (Rpg1 and Rpg5) with ‘73-G1’ (Rpg1), which is susceptible to P. graminis f. sp. avenae, P. graminis f. sp. secalis, and some pathotypes of P. graminis f. sp. tritici. Seedling tests were performed on the F8 RIL population using Australian pathotypes of P. graminis f. sp. tritici, P. graminis f. sp. secalis, P. graminis f. sp. avenae, and a putative somatic hybrid between P. graminis f. sp. tritici and P. graminis f. sp. secalis known as the ‘Scabrum’ rust. Segregation in the responses to all rust isolates for the RILs was identical (50 resistant: 52 susceptible), and fitted a 1:1 ratio (X2 = 0.039, P = 0.843), indicating that resistance to all isolates was monogenetically inherited. Screening of the RILs and the parental lines with perfect markers for the functional Rpg1 and Rpg5 resistance alleles indicated that Rpg1 was fixed, while Rpg5 was positive in all resistant lines and negative in all susceptible lines. This suggests that different formae speciales of P. graminis may share common effectors, and that the Rpg5 locus confers resistance to both P. graminis f. sp. tritici and P. graminis f. sp. secalis and the heterologous formae speciales of P. graminis, P. graminis f. sp. avenae.

scholarly journals Differences in the Methyl Ester Distribution of Homogalacturonans from Near-Isogenic Wheat Lines Resistant and Susceptible to the Wheat Stem Rust Fungus

2003 ◽  
Vol 16 (10) ◽  
pp. 945-952 ◽  
Author(s):  
Nicola Wiethölter ◽  
Barbara Graeßner ◽  
Manfred Mierau ◽  
Andrew J. Mort ◽  
Bruno M. Moerschbacher
Keyword(s):  
Stem Rust ◽  
Rust Fungus ◽  
Methyl Esters ◽  
Resistance Mechanisms ◽  
Wheat Cultivars ◽  
Wheat Stem Rust ◽  
Significant Difference ◽  
The Difference ◽  
Wheat Leaves ◽  
Wheat Lines

Plants possess an efficient nonself surveillance system triggering induced disease resistance mechanisms upon molecular recognition of microbial invaders. Successful pathogens have evolved strategies to evade or counteract these mechanisms, e.g., by the generation of suppressors. Pectic fragments produced during host cell wall degradation can act as endogenous suppressors of the hypersensitive response in wheat leaves. We have isolated and characterized ho-mogalacturonans from cell walls of two wheat cultivars susceptible to the stem rust fungus, Puccinia graminis f. sp. tritici, namely cvs. Prelude and Marquis, and from near-isogenic lines of both cultivars containing the Sr5-gene for hypersensitive rust resistance. Two independent approaches were used to compare their methyl esterification: i) immunochemistry using the monoclonal antibodies JIM5, JIM7, PAM1, and LM7 and ii) chromatography of oligogalacturonides representing stretches of contiguous nonmethyl-esterified GalA residues. The results clearly indicate a significant difference in the homogalacturonans from susceptible and resistant wheat lines. The difference can best be explained by assuming a nonrandom and more blockwise distribution of the methyl esters in the homoga-lacturonans of susceptible wheat cultivars as compared with a presumably more random distribution in the near-isogenic resistant lines. Possible consequences of this difference for the enzymatic generation of endogenous suppressors are discussed.

Retrospective analysis of virulence of the North Caucasian population of wheat stem rust pathogen

2019 ◽  
Vol 1 (81) ◽  
pp. 85-90
Author(s):  
Galina Volkova ◽  
◽  
Olesya Miroshnichenko ◽  
Olga Tarancheva ◽  
◽  
...  
Keyword(s):  
Retrospective Analysis ◽  
Stem Rust ◽  
Caucasian Population ◽  
Wheat Stem Rust ◽  
The North ◽  
Rust Pathogen
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