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

1990 ◽  
Vol 45 (11-12) ◽  
pp. 1151-1155 ◽  
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.

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

1977 ◽  
Vol 55 (11) ◽  
pp. 1445-1452 ◽  
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.

POSTSEEDLING RESPONSE OF WHEAT TO STEM RUST

1975 ◽  
Vol 55 (2) ◽  
pp. 385-390 ◽  
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.

Inheritance of resistance to stem rust in 'Bonza', 'Chris', 'FKN-II-50-17', 'MRFY', 'Thatcher', 'Marquillo', and 'Hope' wheats

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 269-276
Author(s):  
M. Padidam ◽  
D. R. Knott
Keyword(s):  
Triticum Aestivum ◽  
Plant Resistance ◽  
Stem Rust ◽  
Adult Plant Resistance ◽  
Major Gene ◽  
Triticum Aestivum L ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Seedling Resistance ◽  
Minor Genes

Resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks, and Henn.), particularly adult plant resisitance to race 15B-1, was studied in seven wheat (Triticum aestivum L.) cultivars or lines: 'Bonza', 'Chris', 'FKN-II-50-17', 'MRFY', 'Thatcher', 'Marquillo', and 'Hope'. Each of the seven was crossed with a susceptible parent and either F4- or F5-derived lines developed by single seed descent. All of the lines were tested with race 15B-1 in field nurseries. Lines derived from parents carrying seedling resistance to race 15B-1 were also tested as seedlings in the greenhouse with race 15B-1, and in some cases races 56, 29, and C65. The data indicated that 'Bonza' carries Sr6, probably Sr5, an unidentified gene giving resistance to race 56, two unidentified genes for resistance to race C65, and two minor genes that combine to produce intermediate adult plant resistance. 'Chris' carries Sr5, Sr7a, Sr8a, and Sr12. In addition, it may have three minor genes for adult plant resistance. 'FKN-II-50-17' carries Sr6 and may have four minor genes that combine to produce moderate adult plant resistance. 'MRFY', which is seedling susceptible to race 15B-1, carries Sr9b, possibly Sr5, plus an unidentified gene for resistance to C65. In addition, it appears to have one major gene for adult plant resistance plus two or more minor genes. 'Thatcher', 'Marquillo', and 'Hope' had only limited resistance to race 15B-1 in the field and no genetic analysis of their crosses was possible. The four parents that had good resistance to race 15B-1 in the field, 'Bonza', 'Chris', 'FKN-II-50-17', and 'MRFY', all carry minor genes for adult plant resistance that had little effect individually but produced moderate resistance when combined. The genes Sr5 and Sr9b, which have no effect on resistance to 15B-1 is seedlings, were found to significantly increase resistance in adult plants in the field.Key words: stem rust, Puccinia graminis tritici, wheat, Triticum aestivum, adult plant rust resistance.

GENETICS OF STEM RUST RESISTANCE IN WHEAT CULTIVARS ROMANY, Es.P 518/9, BONNY AND TAMA

1975 ◽  
Vol 17 (4) ◽  
pp. 667-674 ◽  
Author(s):  
P. L. Dyck ◽  
G. J. Green
Keyword(s):  
Triticum Aestivum ◽  
Stem Rust ◽  
Rust Resistance ◽  
Triticum Aestivum L ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Wheat Cultivars ◽  
Genetics Of Resistance ◽  
Seedling Resistance ◽  
Moderate Resistance

The genetics of resistance to stem rust (Puccinia graminis tritici) was investigated in wheat (Triticum aestivum L.) cultivars Romany, Es.P 518/9, Bonny and Tama that are resistant to many races in both Canada and Kenya. Seedling resistance in the four cultivars to 12 Canadian races is controlled primarily by previously identified genes. The results indicate that the cultivars have the following genes: Romany — Sr5, Sr6, Sr7a, Sr9b and SrW; Es.P 518/9 — Sr5, Sr6, Sr7a, Sr8, Sr9b, SrW and possibly Sr17; Bonny — Sr6 and Sr11; and Tama — Sr6 and Sr8. Gene SrW confers moderate resistance and is also present in the cultivar Webster.

Inheritance of leaf rust and stem rust resistance in 'Roblin' wheat

Genome ◽  
1993 ◽  
Vol 36 (2) ◽  
pp. 289-293 ◽  
Author(s):  
P. L. Dyck
Keyword(s):  
Triticum Aestivum ◽  
Leaf Rust ◽  
Stem Rust ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Triticum Aestivum L ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Susceptible Cultivar ◽  
Wheat Leaf

The Canadian common wheat (Triticum aestivum L.) cultivar 'Roblin' is resistant to both leaf rust (Puccinia recondita Rob. ex. Desm.) and stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn.). To study the genetics of this resistance, 'Roblin' was crossed with 'Thatcher', a leaf rust susceptible cultivar, and RL6071, a stem rust susceptible line. A set of F6 random lines was developed from each cross. The random lines and the parents were grown in a field rust nursery artificially inoculated with a mixture of P. recondita and P. graminis isolates and scored for rust reaction. The same material was tested with specific races of leaf rust and stem rust. These data indicated that 'Roblin' has Lr1, Lr10, Lr13, and Lr34 for resistance to P. recondita and Sr5, Sr9b, Sr11, and possibly Sr7a and Sr12 for resistance to P. graminis. In a 'Thatcher' background, the presence of Lr34 contributes to improve stem rust resistance, which appears also to occur in 'Roblin'.Key words: Triticum aestivum, wheat, leaf rust resistance, stem rust resistance.

The inheritance of adult plant resistance to stem rust derived from wheat cultivars Bonza and Chris

1997 ◽  
Vol 77 (2) ◽  
pp. 289-292
Author(s):  
D. R. Knott
Keyword(s):  
Triticum Aestivum ◽  
Plant Resistance ◽  
Stem Rust ◽  
Adult Plant Resistance ◽  
Complex Mixture ◽  
Recessive Gene ◽  
Triticum Aestivum L ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Recessive Genes

The wheat (Triticum aestivum L.) cultivars Bonza and Chris have adult plant resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) in addition to genes for specific resistance. Both cultivars were crossed to a susceptible wheat, LMPG. Lines carrying the adult plant resistances of the two parents were produced by selecting for seedling susceptibility in the greenhouse and adult plant resistance in the field to race 15B-1 (TMH). Three homozygous lines derived from Bonza and two from Chris were crossed and backcrossed to LMPG. Backcross F2 families were grown in a field nursery inoculated with a multi-race mixture of eight stem rust isolates including 15B-1. Stem rust severities in percent were recorded. An analysis of the data indicated that adult plant resistance of Bonza was controlled by a single recessive gene and that of Chris by two complementary recessive genes. Since the resistance was effective against a complex mixture of virulent stem rust races, it should be of interest to wheat breeders. Key words: Stem rust, Puccinia graminis, common wheat, Triticum aestivum, adult plant resistance

Production and bioassay of gene-specific RNA determining resistance of wheat to stem rust

1974 ◽  
Vol 52 (12) ◽  
pp. 2489-2497 ◽  
Author(s):  
N. K. Howes ◽  
D. J. Samborski ◽  
R. Rohringer
Keyword(s):  
Triticum Aestivum ◽  
Stem Rust ◽  
Triticum Aestivum L ◽  
Time Interval ◽  
Puccinia Graminis ◽  
Resistant Line ◽  
Incompatible Interaction ◽  
Infection Density

Gene-specific RNA directly involved in resistance of wheat (Triticum aestivum L.) to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn.) was produced only in interactions involving an avirulent race of stem rust. The genotype of the host did not affect the production of this RNA, suggesting that the RNA involved in the expression of resistance is a product of the gene for avirulence.Several parameters affecting the bioassay used for the detection of this active RNA were investigated. These included temperature, infection density, the time interval between infection and injection of extract, and the time interval between injection and harvest.A comparison between the number of necrotic sites produced after injection of active RNA into leaves of the resistant line and the number produced in the incompatible interaction showed that 2–7% of the potentially reactive sites respond in the bioassay by becoming necrotic.The active RNÀ isolated from a stem rust – wheat interaction involving a given gene for avirulence produced a response in bioassay plants only when both the corresponding gene for resistance and stem-rust haustoria were present.

scholarly journals Identification of Resistance to Races of Puccinia graminis f. sp. tritici with Broad Virulence in Triticale (×Triticosecale)

Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 479-484 ◽  
Author(s):  
P. D. Olivera ◽  
Z. A. Pretorius ◽  
A. Badebo ◽  
Y. Jin
Keyword(s):  
South African ◽  
Stem Rust ◽  
Triticum Turgidum ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Cereal Rye ◽  
Infection Types ◽  
Stem Rust Resistance Genes ◽  
Moderately Resistant ◽  
Excellent Source

Triticale (×Triticosecale), an amphiploid of wheat (mainly Triticum turgidum) and cereal rye (Secale cereale), is an excellent source of resistance to wheat stem rust, caused by Puccinia graminis f. sp. tritici. A collection of 567 triticale accessions originating from 21 countries was evaluated at the seedling stage for reaction to races of P. graminis f. sp. tritici with broad virulence, including TTKSK, TRTTF, and TTTTF. A high frequency (78.4%) of accessions was resistant to race TTKSK, with low infection types ranging from 0; to X. A selection of 353 TTKSK-resistant accessions was evaluated for reaction to three South African isolates of P. graminis f. sp. tritici with single and/or combined virulences to stem rust resistance genes SrSatu, Sr27, and SrKw present in triticale. Genes SrSatu, Sr27, and SrKw were postulated to be present in 141 accessions and contributed to TTKSK resistance. The remaining 212 resistant accessions may possess uncharacterized genes or combinations of known genes that could not be determined with these isolates. These accessions were further evaluated for resistance to races TTKST, TPMKC, RKQQC, RCRSC, QTHJC, QCCSM, and MCCFC. Resistance remained effective across the entire set of races in the majority of the accessions (n = 200), suggesting that the resistances are effective against a broad spectrum of virulence. In all, 129 (79.6%) resistant accessions with noncharacterized genes were resistant to moderately resistant in field stem rust nurseries at Debre Zeit (Ethiopia) and St. Paul (Minnesota). Results from evaluating F2 populations derived from resistant–susceptible crosses revealed that resistance to TTKSK in triticale was conferred mostly by single genes with dominant effects.

Genes for stem rust resistance in Thatcher wheat

2009 ◽  
Vol 89 (6) ◽  
pp. 1003-1008
Author(s):  
D R Knott
Keyword(s):  
Triticum Aestivum ◽  
Common Wheat ◽  
Stem Rust ◽  
Rust Resistance ◽  
Triticum Aestivum L ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Genetic Studies ◽  
Number Of Genes ◽  
The Common

The common wheat (Triticum aestivum L.) cultivar Thatcher has resistance to many of the older races of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.). Several genetic studies have shown that its resistance is complex in inheritance. To attempt to clarify the inheritance, 28 lines, each believed to carry a single resistance gene from Thatcher, were developed. The lines were tested with 13 races of stem rust. They fell into 13 types with resistance to from 1 to 11 races. Of the five genes previously identified in Thatcher, only two, Sr9g, and Sr12, were present in the lines. Four lines carried named genes, Sr6, Sr7a, Sr8a and S9d, which had not previously been detected in Thatcher. Thatcher is resistant to 8 of the 13 races. At least one line was resistant to each of the 13 races, including the five to which Thatcher is susceptible. Eleven of the 13 types of lines were resistant to race MCCD to which Thatcher is resistant. Seven of the types were resistant to race TMRT(15B-1) to which Thatcher is susceptible. Clearly, the inheritance of resistance in Thatcher is very complex and involves a considerable number of genes. It carries a surprising number of genes that appear to be hidden by the presence of suppressor genes or transposons.Key words: Common wheat, Triticum aestivum, Puccinia graminis, suppressors, tansposons

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