Distribution of Puccinia striiformis f. sp. tritici races and virulence in wheat growing regions of Kenya from 1970 TO 2014

Plant Disease ◽  
2021 ◽  
Author(s):  
Mercy Wamalwa ◽  
Ruth Wanyera ◽  
Julian Rodriguez-Algaba ◽  
Lesley Boyd ◽  
James Owuoche ◽  
...  

Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a major threat to wheat (Triticum spp.) production worldwide. The objective of this study was to determine the virulence of Pst races prevalent in the main wheat growing regions of Kenya, which includes Mt. Kenya, Eastern Kenya, and the Rift Valley (Central, Southern, and Northern Rift). Fifty Pst isolates collected from 1970 to 1992 and from 2009 to 2014 were virulence phenotyped using stripe rust differential sets, and 45 isolates were genotyped with sequence characterized amplified region (SCAR) markers to differentiate among the isolates and identify aggressive strains PstS1 and PstS2. Virulence corresponding to stripe rust resistance genes Yr1, Yr2, Yr3, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, Yr27 and the seedling resistance in genotype Avocet S were detected. Ten races were detected in the Pst samples obtained from 1970 to 1992, and three additional races were detected from 2009 to 2014, with a single race being detected in both periods. The SCAR markers detected both Pst1 and Pst2 strains in the collection. Increasing Pst virulence was found in the Kenyan Pst population, and that diverse Pst race groups dominated different wheat growing regions. Moreover, recent Pst races in east Africa indicated possible migration of some race groups into Kenya from other regions. This study is important in understanding Pst evolution and virulence diversity and useful in breeding wheat cultivars with effective resistance to stripe rust. Keywords: pathogenicity, Puccinia f. sp. tritici stripe (yellow) rust, Triticum aestivum

2016 ◽  
Vol 67 (10) ◽  
pp. 1064 ◽  
Author(s):  
Beyhan Akin ◽  
Xian Ming Chen ◽  
Alex Morgunov ◽  
Nusret Zencirci ◽  
Anmin Wan ◽  
...  

Stripe (yellow) rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss., is one of the most damaging diseases in wheat and is especially damaging for winter and facultative wheat. The objective of this study was to understand stripe rust resistance in 100 wheat and facultative wheat entries from the International Winter Wheat Improvement Program by conducting experiments in a greenhouse and in four field environments in Washington State, USA, and by genotyping molecular markers linked to Yr genes. Percentages of entries resistant to the rust races at the seedling stage were: PST-17, 44%; PST-37, 32%; PST-43, 45%; PST-45, 49%; PST-116, 18%; PST-100, 17%; and PST-127, 8%. Molecular markers were positive for genes Yr9, Yr17, and Yr18 and negative for Yr5, Yr10, and Yr15. Yr18 was present in 44 entries (44%). By using the highly virulent races PST-127 and PST-100 under controlled conditions, 16 entries were shown to have high-temperature adult-plant (HTAP) resistance and resistant–moderately resistant field reactions at all four field sites. Resistant entries, especially those with HTAP resistance, were also identified in the field experiments.


2021 ◽  
Vol 12 ◽  
Author(s):  
Sandra Rollar ◽  
Manuel Geyer ◽  
Lorenz Hartl ◽  
Volker Mohler ◽  
Frank Ordon ◽  
...  

Stripe rust caused by the biotrophic fungus Puccinia striiformis Westend. is one of the most important diseases of wheat worldwide, causing high yield and quality losses. Growing resistant cultivars is the most efficient way to control stripe rust, both economically and ecologically. Known resistance genes are already present in numerous cultivars worldwide. However, their effectiveness is limited to certain races within a rust population and the emergence of stripe rust races being virulent against common resistance genes forces the demand for new sources of resistance. Multiparent advanced generation intercross (MAGIC) populations have proven to be a powerful tool to carry out genetic studies on economically important traits. In this study, interval mapping was performed to map quantitative trait loci (QTL) for stripe rust resistance in the Bavarian MAGIC wheat population, comprising 394 F6 : 8 recombinant inbred lines (RILs). Phenotypic evaluation of the RILs was carried out for adult plant resistance in field trials at three locations across three years and for seedling resistance in a growth chamber. In total, 21 QTL for stripe rust resistance corresponding to 13 distinct chromosomal regions were detected, of which two may represent putatively new QTL located on wheat chromosomes 3D and 7D.


2016 ◽  
Author(s):  
Shaun Clare ◽  
William Kitcher ◽  
Matthew Gardiner ◽  
Phon Green ◽  
Amelia Hubbard ◽  
...  

ABSTRACTPuccinia striiformis f. sp. hordei, the causal agent of barley stripe rust, is a destructive fungal pathogen that significantly affects barley cultivation. A major constraint in breeding resistant cultivars is the lack of mapping information of resistance (R) genes and their introgression into adapted germplasm. A considerable number of R genes have been described in barley to P. striiformis f. sp. hordei, but only a few loci have been mapped. Previously, Chen and Line (1999) reported two recessive seedling resistance loci in the Ethiopian landrace HOR 1428. In this study, we map two loci that confer resistance to P. striiformis f. sp. hordei in HOR 1428, which are located on chromosomes 3H and 5H. Both loci act as additive effect QTLs, each explaining approximately 20% of the phenotypic variation. We backcrossed HOR 1428 to the cv. Manchuria and selected based on markers flanking the RpsHOR128-5H locus. Saturation of the RpsHOR1428-5H locus with markers in the region found KASP marker K_1_0292 in complete coupling with resistance to P. striiformis f. sp. hordei and was designated Rps9. Isolation of Rps9 and flanking markers will facilitate the deployment of this genetic resource into existing programs for P. striiformis f. sp. hordei resistance.


Plant Disease ◽  
2010 ◽  
Vol 94 (2) ◽  
pp. 221-228 ◽  
Author(s):  
Baotong Wang ◽  
Xiaoping Hu ◽  
Qiang Li ◽  
Baojun Hao ◽  
Bo Zhang ◽  
...  

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is a devastating disease in China. Races CYR32 and CYR33 have been predominant in the recent P. striiformis f. sp. tritici population. To develop molecular markers for these races, initially 86 isolates, most of which were collected in 2007 throughout China, were tested on the set of wheat genotypes for differentiating Chinese P. striiformis f. sp. tritici races, and their genomic DNA were amplified with 94 random amplified polymorphic DNA (RAPD) primers. Twelve isolates were identified as CYR33, 14 as CYR32, and 60 as 13 other races. A 320-bp band was identified to be associated with CYR32 with primer S1271 (5′-CTTCTCGGTC-3′), and a 550-bp band was identified to be specific to CYR33 with primer S1304 (5′-AGGAGCGACA-3′). The two bands were cloned and sequenced. Based on the sequences, sequence characterized amplified region (SCAR) markers CYR32sp1/sp2 and CYR33sp1/sp2 were developed to differentiate CYR32 and CYR33, respectively, from other races. The SCAR markers were validated with DNA samples from wheat leaves inoculated with selected isolates from the 86 isolates and urediniospore DNA samples from an additional 63 isolates collected from 2006 to 2009. The detection of CYR32 and CYR33 with the SCAR markers was completely consistent with the results of the race identification with the set of differential wheat genotypes. Thus, the markers are highly reliable for identification of the two races.


2016 ◽  
Vol 106 (11) ◽  
pp. 1344-1351 ◽  
Author(s):  
K. Esvelt Klos ◽  
T. Gordon ◽  
P. Bregitzer ◽  
P. Hayes ◽  
X. M. Chen ◽  
...  

Quantitative trait loci (QTL) for barley stripe rust resistance were mapped in recombinant inbred lines (RIL) from a ‘Lenetah’ × ‘Grannelose Zweizeilige’ (GZ) cross. GZ is known for a major seedling resistance QTL on chromosome 4H but linked markers suitable for marker-assisted selection have not been developed. This study identified the 4H QTL (log of the likelihood [LOD] = 15.94 at 97.19 centimorgans [cM]), and additional QTL on chromosomes 4H and 6H (LOD = 5.39 at 72.7 cM and 4.24 at 34.46 cM, respectively). A QTL on chromosome 7H (LOD = 2.04 at 81.07 cM) was suggested. All resistance alleles were derived from GZ. Evaluations of adult plant response in Corvallis, OR in 2013 and 2015 provided evidence of QTL at the same positions. However, the minor QTL on 4H was not statistically significant in either location/year, while the 7H QTL was significant in both. The single-nucleotide polymorphism markers flanking the resistance QTL were validated in RIL from a ‘95SR316A’ × GZ cross for their ability to predict seedling resistance. In 95SR316A × GZ, 91 to 92% of RIL with GZ alleles at the major 4H QTL and at least one other were resistant to moderate in reaction. In these populations, at least two QTL were required to transfer the barley stripe rust resistance from GZ.


Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Anmin Wan ◽  
Xianming Chen

Puccinia striiformis f. sp. tritici and P. striiformis f. sp. hordei, the causal agents of stripe rust on wheat and barley, respectively, can change rapidly in virulence, and such changes may overcome resistance in cultivars and result in severe epidemics. To monitor virulence changes in the pathogen populations, isolates obtained from stripe rust samples collected by the authors and collaborators from 17 U.S. states in 2008 and 13 states in 2009 were tested on 20 wheat and 12 barley differential lines to identify races of P. striiformis f. tritici and P. striiformis f. sp. hordei, respectively. In 2008, 33 P. striiformis f. tritici (PST) races were detected, including a new race, PST-138, which was similar to previously identified PST-127 (virulent on wheat differentials 1, 2, 3, 4, 6, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, and 20) but not virulent on differential 8. The five most frequent races were PST-114 (virulent on differentials 1, 3, 4, 8, 9, 10, 11, 12, 14, 16, 17, 18, 19, and 20), PST-100 (virulent on differentials 1, 3, 8, 9, 10, 11, 12, 16, 17, 18, 19, and 20), PST-116 (similar to PST-114 plus virulent on differential 5), PST-101 (similar to PST-100 plus virulent on differential 2), and PST-98 (similar to PST-100 but not virulent on differential 9). In 2009, 26 P. striiformis f. tritici races were identified, including two new races, PST-139 and PST-140. PST-139 was similar to PST-127 but not virulent on differentials 16 and 20. PST-140 was similar to PST-114 but not virulent on differential 9. The five most frequent races were PST-139 (19%), PST-140 (14%), PST-114 (11%), PST-116 (10%), and PST-127 (9%). However, the most widely distributed races were PST-98 (in 10 of the 14 states) and PST-102 (in 7 of the 14 states). Differential genotype AvSYr5NIL (Yr5) was the only one among the 20 differentials that remained resistant to all of the identified races. Virulence diversity of the P. striiformis f. tritici populations was higher west of the Rocky Mountains. For barley stripe rust, P. striiformis f. sp. hordei (PSH)-33 (virulent on barley differentials 1 and 7) was the most common (46%) of the 11 races detected in 2008, including a new race, PSH-82 (virulent only on barley differentials 1 and 11). In 2009, six previously identified races were detected, of which five (PSH-16, PSH-38, PSH-46, PSH-54, and PSH-71) were detected in Washington and two (PSH-54 and PSH-70) in Oregon. The information on P. striiformis f. sp. tritici and P. striiformis f. sp. hordei races should be useful in selecting genes for developing cultivars with effective stripe rust resistance.


2009 ◽  
Vol 99 (10) ◽  
pp. 1209-1215 ◽  
Author(s):  
X. X. Sui ◽  
M. N. Wang ◽  
X. M. Chen

Stripe rust (yellow rust), caused by Puccinia striiformis f. sp. tritici, is one of the most devastating foliar diseases of wheat (Triticum aestivum) worldwide. Growing resistant cultivars is the best approach for control of the disease. Although the stripe rust resistance in spring wheat cv. Zak has been circumvented by a group of races of the pathogen predominant in the United States since 2000, the resistance genes in Zak were unknown. To identify and map the genes for resistance to stripe rust, Zak was crossed with susceptible wheat genotype ‘Avocet Susceptible’. Seedlings of the parents and F1, F2, and F3 progeny were tested with P. striiformis f. sp. tritici races PST-43 and PST-45 under controlled greenhouse conditions. Genetic analysis determined that Zak has a single dominant gene, designated as YrZak, conferring race-specific all-stage resistance. Resistance gene analog polymorphism (RGAP), simple sequence repeat (SSR), and sequence-tagged site (STS) techniques were used to identify molecular markers linked to YrZak. A linkage group of three RGAP, three SSR, and three STS markers was constructed for YrZak using 205 F3 lines. Amplification of the complete set of Chinese Spring nulli-tetrasomic lines with RGAP marker Xwgp102 indicated that YrZak is present on chromosome 2B. The three SSR markers further mapped YrZak to the long arm of chromosome 2B. Amplification of chromosome 2B deletion lines with SSR marker Xgwm501 further confirmed that YrZak is on chromosome 2BL. To determine the genetic distance between YrZak and Yr5, which also is present on chromosome 2BL, 300 F2 plants from cross Zak/Yr5 were tested with PST-43. Six susceptible plants were identified from the F2 population, indicating that YrZak and Yr5 are ≈42 centimorgans apart. The results of race reactions and chromosomal locations indicated that YrZak is different from previously identified genes for resistance to stripe rust. This gene should be useful in monitoring virulence changes in the pathogen population and in studying host–pathogen interactions.


2014 ◽  
Vol 152 (6) ◽  
pp. 906-916 ◽  
Author(s):  
A. BARI ◽  
A. AMRI ◽  
K. STREET ◽  
M. MACKAY ◽  
E. DE PAUW ◽  
...  

SUMMARYStripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a major wheat disease that can inflict yield losses of up to 70% on susceptible varieties under favourable environmental conditions. The timely identification of plant genetic resources likely to possess novel resistance to this disease would facilitate the rapid development of resistant wheat varieties. The focused identification of germplasm strategy (FIGS) approach was used to predict stripe rust resistance in a collection of wheat landraces conserved at ICARDA genebank. Long-term climate data for the collection sites, from which these accessions originated and stripe rust evaluation scores for one group of accessions were presented to three different non-linear models to explore the trait×collection site environment interactions. Patterns in the data detected by the models were used to predict stripe rust resistance in a second and different set of accessions. The results of the prediction were then tested against actual evaluation scores of the disease in the field. The study mimics the real scenario where requests are made to plant genetic resources curators to provide accessions that are likely to possess variation for specific traits such as disease resistance.The models used were able to identify stripe rust-resistant accessions with a high degree of accuracy. Values as high as 0·75 for area under the curve and 0·45 for Kappa statistics, which quantify the agreement between the models’ predictions and the curator's disease scores, were achieved. This demonstrates a strong environmental component in the geographic distribution of resistance genes and therefore supports the theoretical basis for FIGS. It is argued that FIGS will improve the rate of gene discovery and efficiency of mining genetic resource collections for adaptive traits by reducing the number of accessions that are normally required for evaluation to identify such variation.


Plant Disease ◽  
2020 ◽  
Author(s):  
Shuo Huang ◽  
Shengjie Liu ◽  
Yibo Zhang ◽  
Yanzhou Xie ◽  
Xiaoting Wang ◽  
...  

Wheat cultivar Shannong 33 (SN33) has remained highly resistant to stripe rust in the field since its release in 2009. To unravel the genetic architecture of stripe rust resistance, seedlings of 161 recombinant inbred lines (RILs) from the cross Avocet S × SN33 were evaluated with two isolates (PST-Lab.1 and PST-Lab.2) of the stripe rust pathogen (Puccinia striiformis f. sp. tritici) in the greenhouse, and the RILs were evaluated in naturally and/or artificially inoculated field sites during two cropping seasons. The RILs and parents were genotyped with the wheat 55K single nucleotide polymorphism (SNP) array. Three genomic regions conferring seedling resistance were mapped on chromosomes 1DS, 2AS, and 3DS, and four consistent quantitative trait loci (QTL) for adult-plant resistance (APR) were detected on 1BL, 2AS, 3DL, and 6BS. The 2AS locus conferring all-stage resistance was identified as the resistant gene Yr17 located on 2NS translocation. The QTL identified on 1BL and 6BS likely correspond to Yr29 and Yr78, respectively. An APR QTL on 3DL explaining 5.8–12.2% of the phenotypic variation is likely to be new. Molecular marker detection assays with the 2NS segment (Yr17), Yr29, Yr78, and QYrsn.nwafu-3DL on a panel of 420 current Chinese wheat cultivars and breeding lines indicated that these genes were present in 11.4%, 7.6%, 14.8%, and 7.4% entries, respectively. The interactions among these genes/QTL were additive suggesting their potential value in enhancing stripe rust resistance breeding materials as observed in the resistant parent. In addition, we also identified two leaf necrosis genes, Ne1 and Ne2, however, the F1 plants from cross Avocet S × SN33 survived indicating that SN33 probably has another allele of Ne1 which allows to harvest seeds.


Plant Disease ◽  
2021 ◽  
Author(s):  
Cai Sun ◽  
Yike Liu ◽  
Qiang Li ◽  
Baotong Wang ◽  
Shuhui Chen ◽  
...  

Wheat stripe rust, an airborne fungal disease and caused by Puccinia striiformis Westend. f. sp. tritici (Pst), is one of the most devastating diseases on wheat. It is the most effective and economical measure for the diseases control to identify high-level resistance genes and apply in wheat breeding. Chinese wheat cultivar Xike01015 presents high levels of all stage resistance (ASR) to the current predominant Pst race CYR33. In this study, a single dominant gene, designated as YrXk, was identified in Xike01015 conferring resistance to CYR33 with genetic analysis of F2 and BC1 population from cross of Mingxian169 (susceptible) and Xike01015. The specific length amplified fragment sequencing (SLAF-seq) strategy was used to construct linkage map in the F2 population. QTL analysis mapped YrXk to a 12.4 Mb segment on chromosome1BS, explaining over 86.96% phenotypic variance. Gene annotation in the QTL region identified three differential expressed candidate genes , TraesCS1B02G168600.1, TraesCS1B02G170200.1, and TraesCS1B02G172400.1. The qRT-PCR results displayed that TraesCS1B02G170200.1 and TraesCS1B02G168600.1 significantly up-regulated and down-regulated, respectively, and TraesCS1B02G170200.1 slightly up-regulated after changed with CYR33 in the seedling stage, which indicating these genes may function in wheat resistance to stripe rust. The results of this study can be used in wheat breeding for improving resistance to stripe rust.


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