Electron microscopy of susceptible and resistant near-isogenic (sr6/Sr6) lines of wheat infected by Puccinia graminis tritici. III. Ultrastructure of incompatible interact

1979 ◽  
Vol 57 (23) ◽  
pp. 2626-2634 ◽  
Author(s):  
D. E. Harder ◽  
D. J. Samborski ◽  
R. Rohringer ◽  
S. R. Rimmer ◽  
W. K. Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stem Rust ◽  
Stem Rust Resistance ◽  
Temperature Sensitive ◽  
Puccinia Graminis ◽  
Cell Necrosis ◽  
Mitochondrial Membranes ◽  
Wheat Stem Rust ◽  
Mesophyll Cells ◽  
Mother Cells

The interaction between avirulent wheat stem rust and wheat mesophyll cells containing the temperature-sensitive Sr6 gene for stem rust resistance was studied by electron microscopy. Mesophyll cells that were invaded at 26 °C (conditioning compatibility) did not develop any signs of incompatibility after they were transferred to 19 °C, at which temperature incompatibility is normally expressed. In host tissue that appeared to be invaded after the change from 26 to 19 °C, the early ultrastructural symptoms of incompatibility were a more electron-dense and often perforated invaginated host plasmalemma, disruptions of the noninvaginated host plasmalemma, vacuolation of the cytoplasm, and accumulations of electron-dense material along the membranes of the vacuoles. At later stages in the development of incompatible interactions, the electron-dense accumulations along the vacuole membranes increased in size and occurred along chloroplast and mitochondrial membranes. Eventually, the entire protoplasts were electron dense and collapsed. In haustoria and haustorial mother cells, incompatibility was usually expressed by a uniform increase in electron density of the cytoplasm. In the Sr6/P6 interaction at 19 °C, host cell necrosis was not always accompanied by fungal necrosis or vice versa. In Sr5/P5 interactions, which were examined for comparison, the intracellular symptoms of incompatibility were similar to those of the Sr6/P6 interactions.

scholarly journals The nucleolus of wheat stem rust uredospores

1969 ◽  
Vol 47 (12) ◽  
pp. 1887-1889 ◽  
Author(s):  
Stephen Mitchell ◽  
Michael Shaw
Keyword(s):  
Electron Microscopy ◽  
Ribosomal Rna ◽  
Stem Rust ◽  
Ribonucleic Acid ◽  
Acid Formation ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Puccinia Graminis Tritici ◽  
Mean Diameter

Electron microscopy shows that the nuclei in immature uredospores of Puccinia graminis tritici possess prominent nucleoli with a mean diameter of 1.7 ± 0.4 μ. The nucleoli in mature uredospores are much smaller (0.5 μ). This reduction in size of the nucleoli may indicate that ribosomal RNA (ribonucleic acid) formation is repressed as uredospores mature.

scholarly journals Markers Linked to Wheat Stem Rust Resistance Gene Sr11 Effective to Puccinia graminis f. sp. tritici Race TKTTF

2016 ◽  
Vol 106 (11) ◽  
pp. 1352-1358 ◽  
Author(s):  
Jayaveeramuthu Nirmala ◽  
Shiaoman Chao ◽  
Pablo Olivera ◽  
Ebrahiem M. Babiker ◽  
Bekele Abeyo ◽  
...  
Keyword(s):  
Stem Rust ◽  
Rust Resistance ◽  
Genetic Resistance ◽  
Wheat Breeding ◽  
Snp Markers ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Wheat Varieties ◽  
Breeding Lines

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, can cause severe yield losses on susceptible wheat varieties and cultivars. Although stem rust can be controlled by the use of genetic resistance, population dynamics of P. graminis f. sp. tritici can frequently lead to defeat of wheat stem rust resistance genes. P. graminis f. sp. tritici race TKTTF caused a severe epidemic in Ethiopia on Ug99-resistant ‘Digalu’ in 2013 and 2014. The gene Sr11 confers resistance to race TKTTF and is present in ‘Gabo 56’. We identified seven single-nucleotide polymorphism (SNP) markers linked to Sr11 from a cross between Gabo 56 and ‘Chinese Spring’ exploiting a 90K Infinium iSelect Custom beadchip. Five SNP markers were validated on a ‘Berkut’/‘Scalavatis’ population that segregated for Sr11, using KBioscience competitive allele-specific polymerase chain reaction (KASP) assays. Two of the SNP markers, KASP_6BL_IWB10724 and KASP_6BL_IWB72471, were predictive of Sr11 among wheat genetic stocks, cultivars, and breeding lines from North America, Ethiopia, and Pakistan. These markers can be utilized to select for Sr11 in wheat breeding and to detect the presence of Sr11 in uncharacterized germplasm.

scholarly journals Races of Puccinia graminis Identified in the United States During 2003

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1125-1127 ◽  
Author(s):  
Y. Jin
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
The United States ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Stem Rust Resistance Genes ◽  
Rust Resistance Genes

Stem rust of small grain cereals, caused by Puccinia graminis, is a major disease of wheat, barley, and oat. In order to effectively utilize stem rust resistance in the improvement of small grain cereals, it is necessary to monitor the virulence composition and dynamics in the stem rust population. Races of P. graminis from barberry, wheat, barley, and oat were surveyed across the United States during 2003. Aecial infections on barberry were primarily due to P. graminis f. sp. secalis, as inoculations using aeciospores failed to produce infection on wheat and oat. Race QFCS of P. graminis f. sp. tritici was the most common race identified from wheat and barley. Race QFCS has virulence on stem rust resistance genes Sr5, 8a, 9a, 9d, 9g, 10, 17, and 21 that are used for race identification. Race TTTT was identified in 2003. This race possesses virulence to all 16 stem rust resistance genes present in the wheat stem rust differentials and should be targeted in breeding for stem rust resistance. Race QFCN appeared to be a new race in the U.S. stem rust population. Races QCCJ and MCCF were identified, but at low frequencies. Seven races of P. graminis f. sp. avenae were identified from oat, and races NA-27, NA-29, and NA-67 were the predominant races. Race NA-76 was identified for the first time in the United States.

scholarly journals The wheat Sr22, Sr33, Sr35 and Sr45 genes confer resistance against stem rust in barley

2018 ◽  
Author(s):  
M. Asyraf Md. Hatta ◽  
Ryan Johnson ◽  
Oadi Matny ◽  
Mark A. Smedley ◽  
Guotai Yu ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Stem Rust Resistance ◽  
Puccinia Hordei ◽  
Puccinia Graminis ◽  
Golden Promise ◽  
Wheat Stem Rust ◽  
Potential Source ◽  
Barley Leaf

SummaryIn the last 20 years, stem rust caused by the fungus Puccinia graminis f. sp. tritici (Pgt), has re-emerged as a major threat to wheat and barley cultivation in Africa and Europe. In contrast to wheat with 82 designated stem rust (Sr) resistance genes, barley’s genetic variation for stem rust resistance is very narrow with only seven resistance genes genetically identified. Of these, only one locus consisting of two genes is effective against Ug99, a strain of Pgt which emerged in Uganda in 1999 and has since spread to much of East Africa and parts of the Middle East. The objective of this study was to assess the functionality, in barley, of cloned wheat Sr genes effective against Ug99. Sr22, Sr33, Sr35 and Sr45 were transformed into barley cv. Golden Promise using Agrobacterium-mediated transformation. All four genes were found to confer effective stem rust resistance. The barley transgenics remained susceptible to the barley leaf rust pathogen Puccinia hordei, indicating that the resistance conferred by these wheat Sr genes was specific for Pgt. Cloned Sr genes from wheat are therefore a potential source of resistance against wheat stem rust in barley.

scholarly journals First Report of Races TKTTP and TKKTP of Puccinia graminis f. sp. tritici with Virulence to Wheat Stem Rust Resistance Gene Sr24 in Turkey and Tunisia

Plant Disease ◽  
2021 ◽  
Author(s):  
Kumarse Nazari ◽  
Ezgi Kurtulus ◽  
Handan Kavaz ◽  
Omer M. Ozturk ◽  
Yesim Egerci ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Stem Rust ◽  
Rust Resistance ◽  
Infection Type ◽  
Single Gene ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Wheat Cultivars ◽  
Wheat Stem Rust ◽  
First Report

Severe wheat stem rust caused by Puccinia graminis Pers.:Pers. f. sp. tritici Erikss. (Pgt) can result in complete crop failure. In recent years, the increasing frequency and the early onset of stem rust in Central West Asia and North Africa (CWANA) has become a big concern. The Sr24 resistance gene, one of the most effective stem rust resistance genes effective against most P. graminis f. sp. tritici races worldwide, has been widely deployed. Until the recent establishment of virulence to Sr24 within the Ug99 lineage of the pathogen in Africa (Hei et al. 2020; Jin et al. 2008; Patpour et al. 2015), Iraq (Nazari et al., 2021), occasional detections of races virulent to Sr24 were reported in South Africa (Le Roux and Rijkenberg 1987), India (Bhardwaj et al. 1990), Germany (Olivera Firpo et al. 2017), Georgia (Olivera, et al. 2019), and Western Siberia (Skolotneva et al., 2020). During the rust surveys conducted in Sinops, Samsun, and Kastomonu in the Black Sea region in northern Turkey in 2018, 19 isolates were collected. Single pustule (SP) isolates were developed and used in race analysis in the Biosafety Rust Laboratory, Regional Cereal Rust Research Center (RCRRC), Izmir, Turkey. Sample recovery, experimental procedures for pre-inoculation, inoculation, incubation, and race typing were conducted as previously described (Nazari et al. 2021). Among the tested SP isolates, two isolates showed a high infection type (IT) of 33+ on the Sr24 tester line (Little Club/Agent) and a low infection type of 11+ for the source of Sr31 (Benno/6*LMPG-6). Eight SP isolates were further developed from the high IT 33+ pustules collected from the Sr24 tester line. After spore multiplications, they were used in inoculation of the 20 North American stem rust single-gene lines used to differentiate races of P. graminis f. sp. tritici, plus Trident (Sr38+), Siouxland (Sr24+Sr31), and Sisson (Sr31+Sr36). Five SP-derived isolates with IT 33+ on the Sr24 single-gene line collected from Samsun (Alacam – Etyemez; Location: N 41.61889 E 35.55722) and Sinop (Merkez-Sanlıoglu; Location: N 41.85556 E 35.04889) were identified as race TKKTP and the remaining three SP isolates as race TKTTP. In 2020, we detected two isolates of TKKTP among the stem rust samples from Tunisia submitted to RCRRC. These two isolates were collected from bread wheat cultivars Heydna and Tahmet at a trial site near Bou Salem in Western Tunisia (Location: N 36.5351 E 8.95486). Based on the negative results of the Stage 1 test using a suite of four real-time polymerase chain reaction assays diagnostic for the Ug99 race group developed by Szabo (2012), these two races should not belong to the Ug99 race group when compared to the reference Ug99 race TTKTT from Kenya. These races were virulent to Sr5, Sr21, Sr9e, Sr7b, Sr6, Sr8a, Sr9g, Sr9b, Sr30, Sr17, Sr9a, Sr9d, Sr10, SrTmp, Sr24, Sr38, and SrMcN. In addition to these genes, race TKTTP was virulent to Sr36. Both races were avirulent to Sr11 and Sr31. To our knowledge, this is the first report of P. graminis f. sp. tritici races with the Sr24 virulence in Turkey and Tunisia. The results reflect an increasing trend of virulence to Sr24 in the pathogen populations, and raise a great concern given the deployment of the Sr24 resistance gene in widely grown wheat cultivars worldwide.

Effects of the Srl5 allele for resistance on development of the stem rust fungus and cellular responses in wheat

1986 ◽  
Vol 64 (3) ◽  
pp. 626-631 ◽  
Author(s):  
H. D. M. Gousseau ◽  
B. J. Deverall
Keyword(s):  
Stem Rust ◽  
Rust Fungus ◽  
Cell Formation ◽  
Cellular Responses ◽  
Host Cells ◽  
Puccinia Graminis ◽  
Wheat Line ◽  
Cell Necrosis ◽  
Virulent Strains ◽  
Mother Cells

The development of avirulent and virulent strains of stem rust (Puccinia graminis Pers. f.sp. tritici Eriks. & Henn.) in a susceptible wheat line and two cultivars bearing the Sr15 allele for resistance was studied, mainly by fluorescence microscopy. Formation of appressoria, substomatal vesicles, infection hyphae, and the first haustorium was unaffected by resistance. The first effect of Sr15 expression was a slower rate of haustorial mother cell formation and was first seen 48 h after inoculation. Effects on hyphal branching and colony radii followed. Necrosis of host cells was first seen at 42 h, but inspection of individual infection sites showed that necrosis did not coincide with effects on haustorial mother cells. It is possible that deterioration of host cells leading to visible host cell necrosis may be related to effects on rust development. Sr15 expression gave a mesothetic reaction, first seen microscopically 60 h after inoculation. Differences between individual infection sites in this reaction may be related to the timing of the onset of necrosis.

MONOSOMIC ANALYSIS OF GENES CONDITIONING STEM RUST RESISTANCE IN TWO COMMON WHEAT CULTIVARS

1974 ◽  
Vol 16 (2) ◽  
pp. 281-284
Author(s):  
A. K. Sanghi ◽  
E. P. Baker
Keyword(s):  
Common Wheat ◽  
Stem Rust ◽  
Somatic Hybrid ◽  
Rust Resistance ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Monosomic Analysis ◽  
Wheat Cultivars ◽  
Wheat Stem Rust ◽  
Chromosome 3B

The single genes in the cultivars Morocco and Yalta conditioning resistance to stem rust culture 103-H-2, a somatic hybrid between wheat stem rust (Puccinia graminis tritici) and rye stem rust (P. graminis secalis) which possesses unusual genes for avirulence on wheat, were each located by monosomic analysis on chromosome 3B. They were estimated to be approximately 9 map units apart.

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