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

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.

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The Spread of Stem Rust Caused by Puccinia graminis f. sp. tritici, with Virulence on Sr31 in Wheat in Eastern Africa

Plant Disease ◽

10.1094/pd-90-0113a ◽

2006 ◽

Vol 90 (1) ◽

pp. 113-113 ◽

Cited By ~ 106

Author(s):

R. Wanyera ◽

M. G. Kinyua ◽

Y. Jin ◽

R. P. Singh

Keyword(s):

Stem Rust ◽

Rust Resistance ◽

Infection Type ◽

Single Gene ◽

Stem Rust Resistance ◽

Eastern Africa ◽

Puccinia Graminis ◽

High Infection ◽

Infection Types ◽

Sr Genes

Stem rust resistance in wheat cultivars with Sr31 has been effective and durable worldwide for more than 30 years. Isolates of Puccinia graminis f. sp. tritici with virulence to Sr31 were detected in Uganda in 1999 (1). During 2003 and 2004, a majority of current Kenyan cultivars and a large portion of CIMMYT wheat germplasm with gene Sr31 planted in Kenya were susceptible to stem rust. Six isolates collected during 2004 at different locations in Kenya were tested for virulence on the 16 North American stem rust race differentials with the following Sr genes: Sr5, 6, 7b, 8a, 9a, 9b, 9d, 9e, 9g, 10, 11, 17, 21, 30, 36, and Tmp. An extended set of designated Sr genes (Sr13, 19, 22, 24, 25, 26, 29, 31, 32, 33, 35, 37, 39, 40, 44, and Wld-1) was also tested at the seedling stage. An isolate from Uganda collected in 1999 with virulence on Sr31 was used for comparison. Urediniospores suspended in a lightweight mineral oil were inoculated onto 7-day-old seedlings. Inoculated plants were placed in a dew chamber for 14 h at 18°C in the dark and then for an additional period of 3 to 4 h placed under fluorescent light. Plants were incubated in a greenhouse at 18 ± 2°C with a photoperiod of 16 h. Infection types (IT), described by Stakman et al. (3), were assessed after 14 days postinoculation. All isolates from Kenya exhibited a low infection type (IT 0) on line W2691SrTt-1 (donor of Sr36), a low infection type (IT 2) on cv. Triumph 64 (donor of SrTmp), and high infection types (IT 3 or 4) on all other lines in the differential set (2); thus these isolates were keyed to race TTKS. The virulence pattern of the isolate collected in 1999 from Uganda was identical to that from Kenya on the differential set and on the extended set of designated Sr genes. In this study, these isolates produced a high infection type (IT 3) on Einkorn and CnSSr21Tm (a derivative of Triticum monococcum in Chinese Spring background), two sources of Sr21 used in our study, whereas the isolate with Sr31-virulence from Uganda in 1999 was reported to be avirulent on Sr21 (1). These isolates produced high infection types on single gene lines with Sr31 and winter wheat cvs. Custer, Foster, GA-Dozier, Patton, and Pioneer 26R61, which were known to carry the 1BL.1RS translocation with Sr31. These isolates were also virulent on SrWld-1, a gene used in spring wheat for its resistance to North American stem rust isolates. In addition to Sr36 and SrTmp, other stem rust resistance genes that were effective against TTKS at the seedling stage include Sr13, 22, 24, 25, 26, 27, 29, 32, 33, 35, 37, 39, 40, and 44. Cultivars, breeding germplasm, and single gene lines are currently being evaluated for adult plant reaction in Kenya. Results from this study indicated that stem rust isolates with virulence on Sr31 are now wide spread in the Eastern Africa highlands and pose a threat to wheat production in the region, as well as in other wheat production areas where Sr31 resistance is important. A rapid deployment of effective resistance genes to this race in breeding programs throughout Eastern Africa and Asia is needed to reduce this threat. References: (1) Z. A. Pretorius et al. Plant Dis. 84:203, 2000. (2) A. P. Roelfs and J. W. Martens. Phytopathology 78:526, 1988. (3) E. C. Stakman et al. U.S. Department of Agriculture. ARS E-617, 1962.

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

Canadian Journal of Genetics and Cytology ◽

10.1139/g74-031 ◽

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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Temperature‐sensitive wheat stem rust resistance gene Sr15 is effective against Puccinia graminis f. sp. tritici race TTKSK

Plant Pathology ◽

10.1111/ppa.12928 ◽

2018 ◽

Vol 68 (1) ◽

pp. 143-151 ◽

Cited By ~ 2

Author(s):

L. Gao ◽

E. M. Babiker ◽

I. C. Nava ◽

J. Nirmala ◽

Z. Bedo ◽

...

Keyword(s):

Resistance Gene ◽

Stem Rust ◽

Rust Resistance ◽

Stem Rust Resistance ◽

Rust Resistance Gene ◽

Temperature Sensitive ◽

Puccinia Graminis ◽

Stem Rust Resistance Gene ◽

Wheat Stem Rust

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THE INHERITANCE OF PATHOGENICITY IN RACES 111 AND 29 OF WHEAT STEM RUST

Canadian Journal of Genetics and Cytology ◽

10.1139/g69-033 ◽

1969 ◽

Vol 11 (2) ◽

pp. 266-274 ◽

Cited By ~ 4

Author(s):

K. N. Kao ◽

D. R. Knott

Keyword(s):

Stem Rust ◽

Rust Resistance ◽

Single Gene ◽

Stem Rust Resistance ◽

Wheat Stem Rust ◽

Complementary Genes

The inheritance of pathogenicity in wheat stem rust was studied in selfed cultures of races 29 and 111, F1 and F2 cultures of a cross between the two races and cultures from a backcross to race 29. The various cultures were tested on Marquis and Prelude and on a series of lines of these varieties carrying single genes for stem rust resistance. Virulence on Sr 5, Sr 6, Sr 8, Sr 9a, Sr 14 and a gene in Marquis was recessive and in each case there was a single gene for virulence corresponding to each gene for resistance. Virulence on Sr 1 was possibly controlled by two dominant complementary genes. There appeared to be two alleles for virulence on Prelude, one dominant and one recessive.

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Seedling Stage Resistance of Iranian Bread Wheat Germplasm to Race Ug99 of Puccinia graminis f. sp. tritici

Plant Disease ◽

10.1094/pdis-02-12-0138-re ◽

2013 ◽

Vol 97 (3) ◽

pp. 387-392 ◽

Cited By ~ 2

Author(s):

Mohsen Mohammadi ◽

Davoud Torkamaneh ◽

Mehran Patpour

Keyword(s):

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Stem Rust Resistance ◽

Puccinia Graminis ◽

Wheat Cultivars ◽

Breeding Lines ◽

Wheat Germplasm ◽

Stem Rust Resistance Genes ◽

Rust Resistance Genes

Following emergence of Ug99, the new virulent race of Puccinia graminis f. sp. tritici in Africa, a global effort for identification and utilization of new sources of Ug99-resistant germplasm has been undertaken. In this study, we conducted replicated experiments to evaluate the resistance of Iranian wheat germplasm to the TTKSK lineage of the Ug99 race of P. graminis f. sp. tritici. We also evaluated for presence of stem rust resistance genes (i.e., Sr2, Sr24, Sr26, Sr38, Sr39, Sr31, and Sr1RSAmigo) in wheat cultivars and breeding lines widely cultivated in Iran. Our phenotyping data revealed high levels of susceptibility to Ug99 in Iranian bread wheat germplasm. Our genotyping data revealed that Iranian cultivars do not carry Sr24, Sr26, or Sr1RSAmigo. Only a few salt-tolerant cultivars and breeding lines tested positively for Sr2, Sr31, Sr38, or Sr39 markers. In conclusion, the genetic basis for resistance to Ug99 in Iranian wheat cultivars was found to be vulnerable. Acquiring knowledge about existing resistance genes and haplotypes in wheat cultivars and breeding lines will help breeders, cereal pathologists, and policy makers to select and pyramid effective stem rust resistance genes.

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Stem Rust Resistance in A-Genome Diploid Relatives of Wheat

Plant Disease ◽

10.1094/pdis-04-10-0260 ◽

2011 ◽

Vol 95 (8) ◽

pp. 941-944 ◽

Cited By ~ 39

Author(s):

M. N. Rouse ◽

Y. Jin

Keyword(s):

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Infection Type ◽

Genetic Resistance ◽

Wheat Breeding ◽

Stem Rust Resistance ◽

Wheat Stem Rust ◽

A Genome ◽

Stem Rust Resistance Genes

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, has been effectively controlled through the use of genetic resistance. P. graminis f. sp. tritici race TTKSK (Ug99) possesses virulence to many resistance genes that have been used in wheat breeding worldwide. One strategy to aid breeders in developing resistant cultivars is to utilize resistance genes transferred from wild relatives to wheat. Stem rust resistance genes have previously been introgressed from Triticum monococcum to wheat. In order to identify additional resistance genes, we screened 1,061 accessions of T. monococcum and 205 accessions of T. urartu against race TTKSK and four additional P. graminis f. sp. tritici races: TTTTF, TRTTF, QFCSC, and MCCFC. A high frequency of the accessions (78.7% of T. monococcum and 93.0% of T. urartu) were resistant to P. graminis f. sp. tritici race TTKSK, with infection types ranging from 0 to 2+. Among these resistant accessions, 55 T. monococcum accessions (6.4% of the total) were also resistant to the other four races. Associations of resistance in T. monococcum germplasm to different races indicated the presence of genes conferring resistance to multiple races. Comparing the observed infection type patterns to the expected patterns of known genes indicated that previously uncharacterized genes for resistance to race TTKSK exist in both T. monococcum and T. urartu.

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Identification and characterization of Sr22b , a new allele of the wheat stem rust resistance gene Sr22 effective against the Ug99 race group

Plant Biotechnology Journal ◽

10.1111/pbi.13737 ◽

2021 ◽

Author(s):

Jing Luo ◽

Matthew N. Rouse ◽

Lei Hua ◽

Hongna Li ◽

Boshu Li ◽

...

Keyword(s):

Resistance Gene ◽

Stem Rust ◽

Rust Resistance ◽

Stem Rust Resistance ◽

Rust Resistance Gene ◽

Stem Rust Resistance Gene ◽

Wheat Stem Rust ◽

Identification And Characterization

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Identification of stem rust resistance genes in wheat cultivars in China using molecular markers

PeerJ ◽

10.7717/peerj.4882 ◽

2018 ◽

Vol 6 ◽

pp. e4882 ◽

Cited By ~ 7

Author(s):

Xiaofeng Xu ◽

Depeng Yuan ◽

Dandan Li ◽

Yue Gao ◽

Ziyuan Wang ◽

...

Keyword(s):

Molecular Markers ◽

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Genetic Material ◽

Stem Rust Resistance ◽

Wheat Cultivars ◽

Wheat Stem Rust ◽

Stem Rust Resistance Genes ◽

Rust Resistance Genes

Wheat stem rust caused by Puccinia graminis f. sp. tritici Eriks. & E. Henn. (Pgt), is a major disease that has been effectively controlled using resistance genes. The appearance and spread of Pgt races such as Ug99, TKTTF, and TTTTF, which are virulent to most stem rust-resistant genes currently deployed in wheat breeding programs, renewed the interest in breeding cultivars resistant to wheat stem rust. It is therefore important to investigate the levels of resistance or vulnerability of wheat cultivars to Pgt races. Resistance to Pgt races 21C3CTHQM, 34MKGQM, and 34C3RTGQM was evaluated in 136 Chinese wheat cultivars at the seedling stage. A total of 124 cultivars (91.2%) were resistant to the three races. Resistance genes Sr2, Sr24, Sr25, Sr26, Sr31, and Sr38 were analyzed using molecular markers closely linked to them, and 63 of the 136 wheat cultivars carried at least one of these genes: 21, 25, and 28 wheat cultivars likely carried Sr2, Sr31, and Sr38, respectively. Cultivars “Kehan 3” and “Jimai 22” likely carried Sr25. None of the cultivars carried Sr24 or Sr26. These cultivars with known stem rust resistance genes provide valuable genetic material for breeding resistant wheat cultivars.

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