Anthranilate Synthase and Chorismate Mutase Activities in Stem Rust-Inoculated and Elicitor-Treated Resistant, Moderately Resistant, and Susceptible Near-Isogenic Wheat Lines

Abstract Anthranilate synthase and chorismate mutase activities which control the flow of substrate from chorismate into the tryptophan pathway and into the phenylalanine/tyrosine pathway, respectively, were examined in three near isogenic wheat lines of Triticum aestivum L. (cv. Prelude Sr 5, highly resistant to stem rust infection; cv. Prelude Sr 24, moderately resistant; cv. Prelude srx, susceptible). The activities of both enzymes were found to increase in response to inoculation with the stem rust fungus Puccinia graminis f. sp. tritici or treatment with Pgt elicitor. Thus, both the tryptophan branch and the phenylalanine branch appear to contribute to the resistance response in wheat leaves. Only the cytosolic but not the plastidic fraction of the enzyme activities appears to be affected by fungal infection or elicitor treatment. Some differences with respect to degree and time dependency of enzyme activation were noticed between the three wheat lines following inoculation but not after treatment with the Pgt elicitor.

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Peace hard red spring wheat

Canadian Journal of Plant Science ◽

10.4141/cjps2013-286 ◽

2014 ◽

Vol 94 (7) ◽

pp. 1297-1302 ◽

Cited By ~ 2

Author(s):

D. G. Humphreys ◽

T. F. Townley-Smith ◽

O. M. Lukow ◽

B. D. McCallum ◽

T. G. Fetch ◽

...

Keyword(s):

Spring Wheat ◽

Stem Rust ◽

Triticum Aestivum L ◽

Head Blight ◽

Canadian Prairies ◽

Hard Red Spring Wheat ◽

Quality Specifications ◽

End Use ◽

Moderately Resistant ◽

Highly Virulent

Humphreys, D. G., Townley-Smith, T. F., Lukow, O. M., McCallum, B. D., Fetch, T. G., Gilbert, J. A., Menzies, J. G., Tkachuk, V., Brown, P. D. and Fox, S. L. 2014. Peace hard red spring wheat. Can. J. Plant Sci. 94: 1297–1302. Peace is a hard red spring wheat (Triticum aestivum L.) adapted to the shorter-season wheat-growing regions of the Canadian prairies. Peace was evaluated in the Parkland Wheat Cooperative Test in 1999, 2000 and 2001. Peace exhibited grain yield similar to the check cultivars over 2 yr (1999–2000; Neepawa and Roblin) and over 3 yr (1999–2001; AC Barrie and AC Splendor) Peace matured a day earlier than AC Barrie but was 2 d later than AC Splendor over 3 yr of testing (1999–2001) and was a day later than Neepawa and Roblin over 2 yr of testing (1999–2000). Peace had test weight similar to the check cultivars. Peace was moderately resistant to leaf rust and loose smut and resistant to stem rust including the highly virulent Ug99 race of stem rust and common bunt. Peace was moderately susceptible to Fusarium head blight. Peace meets the end-use quality specifications of the Canada Western Red Spring wheat class.

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Alterations in 1,4-Benzoxazinone Levels Following Inoculation with Stem Rust in Wheat Leaves Carrying Various Alleles for Resistance and Their Possible Role as Phytoalexins in Moderately Resistant Leaves

Zeitschrift für Naturforschung C ◽

10.1515/znc-1990-11-1211 ◽

1990 ◽

Vol 45 (11-12) ◽

pp. 1151-1155 ◽

Cited By ~ 21

Author(s):

Claudia Bücker ◽

Hans J. Grambow

Keyword(s):

Triticum Aestivum ◽

Stem Rust ◽

Triticum Aestivum L ◽

Puccinia Graminis ◽

Conversion Product ◽

Near Isogenic Lines ◽

Wheat Leaves ◽

Infection Types ◽

Moderately Resistant

The contents of 1,4-benzoxazinone derivatives in wheat plants infected with Puccinia graminis Pers. f. sp. tritici Ericss. & Henn, race 32, and in uninfected controls were examined in four near-isogenic lines of different infection types: Triticum aestivum L., cultivar Prelude Sr5 (highly resistant), Sr24, Sr26 (moderately resistant), and srx (susceptible). In all infection types the contents of DIMBOA -glc and HMBOA -glc decrease with time in the uninfected controls as well as in the infected plants. However, following inoculation, the synthesis of HDIBOA -glc is drastically increased in the moderately resistant cultivars. The results suggest that this fully methylated 1,4-benzoxazinone may function as a phytoalexin in this type of interaction. The benzoxazolinone MBOA which has been described as an in vitro conversion product of the benzoxazinones mentioned above is not detected in inoculated or uninoculated leaves.

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POSTSEEDLING RESPONSE OF WHEAT TO STEM RUST

Canadian Journal of Plant Science ◽

10.4141/cjps75-061 ◽

1975 ◽

Vol 55 (2) ◽

pp. 385-390 ◽

Cited By ~ 2

Author(s):

R. M. DE PAUW ◽

K. W. BUCHANNON

Keyword(s):

Triticum Aestivum ◽

Stem Rust ◽

Triticum Aestivum L ◽

Puccinia Graminis ◽

Horizontal Resistance ◽

Leaf Stage ◽

The Third ◽

Stages Of Growth ◽

Growing Conditions ◽

Moderately Resistant

The seedling and postseedling reactions of five cultivars of Triticum aestivum L. to eight races of Puccinia graminis f. sp. tritici Eriks. and E. Henn. were compared under Kenya growing conditions. The seedling and postseedling reactions of Florence Aurore to eight races of stem rust were similar. The cultivars Hope, Africa Mayo, Kenya Page, and Conley differed from Florence Aurore in that seedlings of these cultivars were susceptible to several races, whereas postseedlings expressed a degree of resistance to these same races. Postseedling resistance may be identical with horizontal resistance. The stage of growth during which resistance became effective was determined by inoculating each cultivar at various stages of growth. The reaction class of Hope and Africa Mayo changed from susceptible to moderately susceptible between the fourth- and the fifth-leaf stage to races EA4(295) and EA8(40); the reaction class of Kenya Page and Conley changed from susceptible to moderately resistant to both races at about the third-leaf stage. The stage of growth during which resistance became expressed was independent of the test race.

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Photosynthesis in stem rust-infected, resistant and susceptible near-isogenic wheat leaves

Canadian Journal of Botany ◽

10.1139/b94-124 ◽

1994 ◽

Vol 72 (7) ◽

pp. 990-997 ◽

Cited By ~ 3

Author(s):

B. M. Moerschbacher ◽

P. Vander ◽

C. Springer ◽

U. Noll ◽

G. Schmittmann

Keyword(s):

Membrane Proteins ◽

Chlorophyll Content ◽

Stem Rust ◽

Thylakoid Membrane ◽

Photosynthetic Activity ◽

Rust Fungus ◽

Puccinia Graminis ◽

Thylakoid Membrane Proteins ◽

Induced Changes ◽

Moderately Resistant

Secondary leaves of three near-isogenic lines of the wheat (Triticum aestivum) cultivar Prelude, differing in their degree of resistance to the wheat stem rust fungus (Puccinia graminis f.sp. tritici) race 32, were inoculated with uredospores of the fungus 12 days after germination. Photosynthetic O2 evolution, chlorophyll content, 3-phosphoglycerate content, and the gel electrophoretic pattern of thylakoid membrane proteins were investigated in rust-infected and healthy plants of the fully susceptible isoline Prelude, the moderately resistant isoline Prelude-Sr24, and the highly resistant isoline Prelude-Sr5. The rate of net photosynthesis, expressed per unit leaf area, was not significantly changed in any of the three near-isogenic lines during the early stages of infection, then increased slightly in the highly resistant line, while decreasing in the moderately resistant and fully susceptible lines. In the moderately resistant plants, this decrease continued linearly until 8 days after inoculation when no photosynthetic activity was detectable. In the susceptible line, the decrease gradually slowed down around 4–6 days after inoculation and photosynthetic activity remained constant thereafter. The chlorophyll content decreased only slightly during infection in highly resistant plants, but chlorophyll eventually disappeared completely from the infected, moderately resistant plants. The initially similarly strong decrease in chlorophyll content in the susceptible plants gradually came to a halt during the later stages of infection. Expressed per unit chlorophyll, photosynthetic O2 evolution increased slightly in highly resistant plants, remained unchanged in moderately resistant plants, and decreased to a stable level in the susceptible plants. The infection-induced changes in the 3-phosphoglycerate content closely resembled the changes in O2 evolution. No infection-induced changes were observed in the thylakoid membrane proteins from leaves of all three isolines. The results are discussed in relation to previously described changes in the primary metabolism of the three near-isogenic wheat lines after inoculation with the stem rust fungus, namely polyamine content, fructose-2,6-bisphosphate content, respiratory activity, invertase activity, and assimilate contents. Key words: Triticum aestivum, Puccinia graminis f.sp. tritici, O2 evolution, chlorophyll, 3-phosphoglycerate, thylakoid membrane proteins.

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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.10.945 ◽

2003 ◽

Vol 16 (10) ◽

pp. 945-952 ◽

Cited By ~ 47

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.

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AAC Redwater hard red spring wheat

Canadian Journal of Plant Science ◽

10.1139/cjps-2016-0276 ◽

2017 ◽

Vol 97 (6) ◽

pp. 1188-1194

Author(s):

Y. Zi ◽

D.G. Humphreys ◽

A. Olson ◽

B.D. McCallum ◽

T.G. Fetch ◽

...

Keyword(s):

Triticum Aestivum ◽

Spring Wheat ◽

Stem Rust ◽

Triticum Aestivum L ◽

Canadian Prairies ◽

Hard Red Spring Wheat ◽

Field Reaction ◽

Quality Specifications ◽

End Use ◽

Moderately Resistant

AAC Redwater is a hard red spring wheat (Triticum aestivum L.) adapted to the shorter season wheat-growing regions of the Canadian prairies. AAC Redwater was evaluated in the Parkland Wheat Cooperative Test in 2009, 2010, and 2011. AAC Redwater was significantly (P < 0.05) higher yielding than Katepwa (6.4%) and AC Splendor (7.5%) and was not significantly different in grain yield compared to CDC Teal and CDC Osler. AAC Redwater had maturity similar to AC Splendor, matured a day earlier than Katepwa, and was significantly earlier maturing (2 d) than CDC Teal and CDC Osler. AAC Redwater was significantly shorter than all check cultivars and had a similar mean lodging score to the check cultivars. AAC Redwater is resistant to moderately resistant to leaf and stem rust, comparable to AC Splendor. AAC Redwater was resistant to intermediate in its field reaction to stripe rust and intermediate in its reaction to the Ug99 stem rust race, similar to CDC Teal. At the time of registration, AAC Redwater met the end-use quality specifications of the Canada Western Red Spring wheat class.

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Histological studies on host-cell necrosis conditioned by the Sr6 gene for resistance in wheat to stem rust

Canadian Journal of Botany ◽

10.1139/b77-169 ◽

1977 ◽

Vol 55 (11) ◽

pp. 1445-1452 ◽

Cited By ~ 28

Author(s):

D. J. Samborski ◽

W. K. Kim ◽

R. Rohringer ◽

N. K. Howes ◽

R. J. Baker

Keyword(s):

Triticum Aestivum ◽

Stem Rust ◽

Fungal Growth ◽

Triticum Aestivum L ◽

Host Cells ◽

Puccinia Graminis ◽

Near Isogenic Lines ◽

Cell Necrosis ◽

Calcofluor White ◽

Histological Studies

Seedlings of resistant (Sr6) and susceptible (sr6) near-isogenic lines of wheat (Triticum aestivum L.) were inoculated with a race of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.) that was avirulent on the line with Sr6 and they were kept at 19, 25, 26, and 27 °C. Fluorescence microscopy was used to detect autofluorescing necrotic host cells and rust colonies after these were stained with a fiuorochrome (Calcofluor White M2R New).In leaves containing the Sr6 gene, a smaller percentage of colonies grown at 25 °C had necrotic cells associated with them than those that were grown at 19 °C. The incidence of colony-associated necrosis in these leaves could be further reduced by increasing the temperature to 26 °C and 27 °C. Similarly, the number of necrotic host cells per colony decreased with an increase in temperature. Colonies in genotypically resistant leaves were usually smaller than those in genotypically susceptible leaves, but the differences in colony sizes between these two lines decreased at the higher temperatures.When infected plants containing the Sr6 gene were kept for varying times at 25 °C and then were transferred to 19 °C, there was significantly less fungal growth and more necrosis than in plants kept continuously at 25 °C. This necrosis occurred largely in those cells that were invaded after the transfer to 19 °C, when the Sr6 gene was activated.

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