scholarly journals Identification of Wheat Gene Sr35 That Confers Resistance to Ug99 Stem Rust Race Group

Science ◽  
2013 ◽  
Vol 341 (6147) ◽  
pp. 783-786 ◽  
Author(s):  
Cyrille Saintenac ◽  
Wenjun Zhang ◽  
Andres Salcedo ◽  
Matthew N. Rouse ◽  
Harold N. Trick ◽  
...  

Wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a devastating disease that can cause severe yield losses. A previously uncharacterized Pgt race, designated Ug99, has overcome most of the widely used resistance genes and is threatening major wheat production areas. Here, we demonstrate that the Sr35 gene from Triticum monococcum is a coiled-coil, nucleotide-binding, leucine-rich repeat gene that confers near immunity to Ug99 and related races. This gene is absent in the A-genome diploid donor and in polyploid wheat but is effective when transferred from T. monococcum to polyploid wheat. The cloning of Sr35 opens the door to the use of biotechnological approaches to control this devastating disease and to analyses of the molecular interactions that define the wheat-rust pathosystem.

Science ◽  
2013 ◽  
Vol 341 (6147) ◽  
pp. 786-788 ◽  
Author(s):  
Sambasivam Periyannan ◽  
John Moore ◽  
Michael Ayliffe ◽  
Urmil Bansal ◽  
Xiaojing Wang ◽  
...  

Wheat stem rust, caused by the fungus Puccinia graminis f. sp. tritici, afflicts bread wheat (Triticum aestivum). New virulent races collectively referred to as “Ug99” have emerged, which threaten global wheat production. The wheat gene Sr33, introgressed from the wild relative Aegilops tauschii into bread wheat, confers resistance to diverse stem rust races, including the Ug99 race group. We cloned Sr33, which encodes a coiled-coil, nucleotide-binding, leucine-rich repeat protein. Sr33 is orthologous to the barley (Hordeum vulgare) Mla mildew resistance genes that confer resistance to Blumeria graminis f. sp. hordei. The wheat Sr33 gene functions independently of RAR1, SGT1, and HSP90 chaperones. Haplotype analysis from diverse collections of Ae. tauschii placed the origin of Sr33 resistance near the southern coast of the Caspian Sea.


Plant Disease ◽  
2002 ◽  
Vol 86 (6) ◽  
pp. 568-572 ◽  
Author(s):  
D. V. McVey ◽  
D. L. Long ◽  
J. J. Roberts

Wheat stem rust caused negligible yield losses in 1997 and 1998. Overwintering sites were found in central and east-central Louisiana in 1997, and in northwestern Florida, northeastern Louisiana, and central Texas in 1998. Race Pgt-TPMK predominated in 1997 with 69% of 100 isolates with race RCRS next at 11%. In 1998, race RCRS predominated with 55% of 132 isolates, and TPMK occurred at 10%. Race QFCS occurred at 8% in 1997 and 31% in 1998. Races QCCS and QTHJ were found in 1997, and races QFBS, RKMQ, RKQQ, and RCMS were found in 1998. Race QCCJ, virulent to barley with the Rpg1 gene for stem rust resistance, was not found from wheat in 1997 or 1998. No virulence was found to wheat lines with Sr 13, 22, 24, 25, 26, 27, 29, 30, 31, 32, 37, Gt, or Wld-1. Oat stem rust was found earlier in 1997 than 1998, but was more widespread in 1998. Race NA27, virulent to Pg-1, -2, -3, -4, and -8, was the predominant race in the United States in 1997 (79% of 116 isolates) and again in 1998 (79% of 116 isolates). NA16, virulent to Pg-1, -3, and -8, was found in the south (1997 and 1998), and NA5, virulent to Pg-2 and -15, and NA10, virulent to Pg-2, -3, and -15, were found in the west (1997).


Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 557-557 ◽  
Author(s):  
I. L. Hale ◽  
I. Mamuya ◽  
D. Singh

Since the first detection of race TTKSK (syn. Ug99) in Uganda in 1999 (2), the migration and evolution of Sr31-virulent races of Puccinia graminis f. sp. tritici [Pgt] have been closely monitored, particularly in Kenya and countries north, along the likely trajectory of migration to major wheat-producing regions of Asia. More recently, surveillance efforts have been undertaken to the south as well, and Ug99-related races have been detected in South Africa and Zimbabwe (3,4). Here we report for the first time results of a survey conducted in Tanzania. Systematic race surveillance provides data not only on the current distribution of the Ug99 race group, but also on the possible points of origin as well as the pace and probable paths of dispersal of future races from the region. In this context, the presence or absence of the Ug99 group of wheat stem rust races in adjacent countries like Tanzania assumes regional, and possibly global, relevance. A preliminary survey conducted in September 2006 indicated the presence of Sr31-virulent races of Pgt outside Slahhamo Village (3°15′S, 35°48′E) in the Ngorongoro highlands of northern Tanzania, based on compatible reactions with cv. K-Mamba (a.k.a. Mwamba), a cultivar whose pedigree indicates the presence of Sr31. A broader survey was conducted in August 2009, during which infected tissue was collected from currently-grown cultivars in research plots and on large estates, as well as from the mixes of older cultivars common on smallholder farms. In all, Pgt-infected samples were collected from one site in the Arusha region [Monduli (3°16′ S, 36°24′E)], three sites in the Ngorongoro highlands [Karatu (3°20′ S, 35°40′ E), Upper Kitete (3°14′ S, 35°53′ E), and Slahhamo], one site in the Manyara region [Hanang (4°43′ S, 35°40′ E)], and one site in the Mbeya region [southern highlands (8°87′ S, 33°40′ E)], thereby giving representation to all four major wheat growing areas in the country. Sample storage, inoculation, incubation, disease assessment, and derivation of single-pustule cultures were all performed according to the methods described by Jin et al. (1). In addition to the 20 differentials in the expanded Pgt differential set of North America, we included two supplemental tester lines: Siouxland (Sr24 + Sr31) and Sisson (Sr31 + Sr36). Each single-pustule-derived isolate was evaluated for virulence on the differential and supplemental lines at least twice. A total of 39 single-pustule isolates were derived from the six collection sites. All 39 isolates were identified as belonging to the Ug99 race group, with six identified as TTKSK (all four regions), 30 identified as TTKST (Sr31 + Sr24 virulence; Arusha region and the Ngorongoro highlands), and three identified as TTTSK (Sr31 + Sr36 virulence; Manyara region and the Ngorongoro highlands). The results of this study suggest that, to more precisely locate the “hot spots” and thereby gain a better understanding of the mechanisms of novel race emergence in East Africa, it would be prudent to include Tanzania, heretofore a blank area on the wheat rust surveillance map, in future systematic race monitoring efforts. References: (1) Y. Jin et al. Plant Dis. 92:923, 2008. (2) Z. A. Pretorius et al. Plant Dis. 84:203, 2000. (3) Z. A. Pretorius et al. Plant Dis. 94:784, 2010. (4) Z. A. Pretorius et al. Plant Dis. 96:590, 2012.


Plant Disease ◽  
1999 ◽  
Vol 83 (9) ◽  
pp. 871-875 ◽  
Author(s):  
D. V. McVey ◽  
D. L. Long ◽  
J. J. Roberts

Stem rust caused negligible yield losses in 1996 in the United States. Wheat stem rust was first found during the second week of April in a field of soft red winter wheat southwest of Houston, Texas. Race Pgt-TPMK continues to predominate, with 66% of 273 isolates from 100 collections. TPMK represented 76 and 63% of the isolates from wheat in fields and nurseries, respectively. Race QFCS was identified at a frequency of 12 and 29% from farm fields and nurseries, respectively, and 26% overall. Eight other races consisted of 3% or less of the isolates. From barley, race QCCJ, virulent to the Rpg-1 gene for resistance to stem rust, was identified in only 12% of 77 isolates of 27 collections, while TPMK consisted of 64% of the isolates. No virulence was found to wheat lines with genes Sr9b, 13, 22, 24, 25, 26, 27, 29, 30, 31, 32, 37, Gt, or Wld-1. Oat stem rust was first found in late April in southern Louisiana and central Texas. Race NA-27, virulent to Pg-1, -2, -3, -4, and -8, was again the predominant race in the United States, comprising 91% of 93 isolates from 36 collections. NA-5 and NA-16 were the other two races identified, comprising 4% each.


2021 ◽  
Author(s):  
Laetitia Willocquet ◽  
Vittorio Rossi ◽  
Serge Savary

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 941-944 ◽  
Author(s):  
M. N. Rouse ◽  
Y. Jin

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.


Plant Disease ◽  
2005 ◽  
Vol 89 (2) ◽  
pp. 159-163 ◽  
Author(s):  
P. D. Peterson ◽  
K. J. Leonard ◽  
J. D. Miller ◽  
R. J. Laudon ◽  
T. B. Sutton

A federal and state program operated from 1918 until the 1980s to eradicate common barberry (Berberis vulgaris), the alternate host of Puccinia graminis, from the major areas of cereal production in the United States. Over 500 million bushes were destroyed nationally during the program, approximately 1 million in Minnesota. Some sites in Minnesota where barberry bushes were destroyed remained in the “active” class when eradication was phased out in the 1980s. Active sites were defined as those on which there was still a possibility of emergence of barberry seedlings or sprouts arising from the parent bush. In the present study, from 1998 to 2002, 72 of the approximately 1,200 active sites in Minnesota were surveyed. Areas within 90 m of mapped locations of previously destroyed bushes were searched carefully at each site. Reemerged barberry plants were found on 32 sites. The reproductive status and GPS coordinates were recorded for each reemerged bush. More than 90% of the barberry bushes were found in counties with less than 400 ha of wheat per county, mostly in southeastern Minnesota, but one bush was found in a major wheat-producing county in northwestern Minnesota. Reemergence of barberry may serve as a source of new wheat stem rust races in future epidemics.


Plant Disease ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 1939-1943
Author(s):  
Xian Xin Wu ◽  
Qiu Jun Lin ◽  
Xin Yu Ni ◽  
Qian Sun ◽  
Rong Zhen Chen ◽  
...  

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is one of the most serious fungal diseases in wheat production, seriously threatening the global supply of wheat and endangering food security. The present study was conducted to evaluate wheat monogenic lines with known Sr genes to the most prevalent P. graminis f. sp. tritici races in China. In addition, wheat lines introduced from the International Maize and Wheat improvement Center (CIMMYT) with resistance to the Ug99 race group were also evaluated with the prevalent Chinese P. graminis f. sp. tritici races. The monogenic lines containing Sr9e, Sr21, Sr26, Sr31, Sr33, Sr35, Sr37, Sr38, Sr47, and SrTt3 were effective against races 21C3CTTTM, 34C0MRGSM, and 34C3MTGQM at both seedling and adult-plant stages. In contrast, monogenic lines containing Sr6, Sr7b, Sr8a, Sr9a, Sr9b, Sr9d, Sr9f, Sr9g, Sr13, Sr16, Sr18, Sr19, Sr20, Sr24, Sr28, Sr29, and Sr34 were highly susceptible to these races at both seedling and adult-plant stages. Lines with Sr5, Sr10, Sr13, Sr14, Sr15, Sr17, Sr21, Sr22, Sr23, Sr25, Sr27, Sr29, Sr30, Sr32, Sr36, and Sr39 were resistant to one or more of the tested races. Among the 123 CIMMYT lines, 38 (30.9%) showed varying levels of susceptibility to Chinese P. graminis f. sp. tritici races. The results should be useful for breeding wheat cultivars with resistance to stem rust.


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