scholarly journals Wheat genetic loci conferring resistance to stripe rust in the face of genetically diverse races of the fungus Puccinia striiformis f. sp. tritici

Author(s):  
Laura Bouvet ◽  
Lawrence Percival-Alwyn ◽  
Simon Berry ◽  
Paul Fenwick ◽  
Camila Campos Mantello ◽  
...  

Abstract Key message Analysis of a wheat multi-founder population identified 14 yellow rust resistance QTL. For three of the four most significant QTL, haplotype analysis indicated resistance alleles were rare in European wheat. Abstract Stripe rust, or yellow rust (YR), is a major fungal disease of wheat (Triticum aestivum) caused by Puccinia striiformis Westend f. sp. tritici (Pst). Since 2011, the historically clonal European Pst races have been superseded by the rapid incursion of genetically diverse lineages, reducing the resistance of varieties previously showing durable resistance. Identification of sources of genetic resistance to such races is a high priority for wheat breeding. Here we use a wheat eight-founder multi-parent population genotyped with a 90,000 feature single nucleotide polymorphism array to genetically map YR resistance to such new Pst races. Genetic analysis of five field trials at three UK sites identified 14 quantitative trait loci (QTL) conferring resistance. Of these, four highly significant loci were consistently identified across all test environments, located on chromosomes 1A (QYr.niab-1A.1), 2A (QYr.niab-2A.1), 2B (QYr.niab-2B.1) and 2D (QYr.niab-2D.1), together explaining ~ 50% of the phenotypic variation. Analysis of these four QTL in two-way and three-way combinations showed combinations conferred greater resistance than single QTL, and genetic markers were developed that distinguished resistant and susceptible alleles. Haplotype analysis in a collection of wheat varieties found that the haplotypes associated with YR resistance at three of these four major loci were rare (≤ 7%) in European wheat, highlighting their potential utility for future targeted improvement of disease resistance. Notably, the physical interval for QTL QYr.niab-2B.1 contained five nucleotide-binding leucine-rich repeat candidate genes with integrated BED domains, of which two corresponded to the cloned resistance genes Yr7 and Yr5/YrSp. Graphical abstract

2021 ◽  
Author(s):  
Laura Bouvet ◽  
Lawrence Percival-Alwyn ◽  
Simon Berry ◽  
Paul Fenwick ◽  
Camila Campos Mantello ◽  
...  

Abstract Yellow rust (YR), or stripe rust, is a major fungal disease of wheat (Triticum aestivum) caused by Puccinia striiformis f. sp. tritici (Pst). Since 2011, the historically clonal European Pst races have been superseded by the rapid incursion of genetically diverse lineages, reducing the resistance of varieties that previously showed durable resistance. Identification of sources of genetic resistance to such races is a high priority for wheat breeding. Here we use a wheat eight-founder multi-parent population genotyped with a 90,000 feature single nucleotide polymorphism array to genetically map adult plant YR resistance to such new Pst races. Analysis of five trials, at three sites in the UK, consistently identified four highly significant quantitative trait loci (QTL) across all test environments, located on chromosomes 1A (QYr.niab-1A.1), 2A (QYr.niab-2A.1), 2B (QYr.niab-2B.1) and 2D (QYr.niab-2D.1). Together these explained ~ 50% of the phenotypic variation, and genetic markers were developed that distinguished resistant and susceptible alleles. Analysis of these QTL in two-way and three-way combinations showed combinations conferred greater resistance than single QTL. Four additional major-effect QTL were detected in two or more trials, together explaining 15–20% of the phenotypic variation, as well as six minor QTL. Genomic analysis found the median physical interval size of these eight QTL to be 19.8 Mbp, and QYr.niab-2A.1 and QYr.niab-2D.1 to be at homoeologous locations on the group-2 chromosomes. Notably, the QYr.niab-2B.1 physical interval contained five nucleotide-binding leucine-rich repeat (NLR) candidate genes with integrated BED domains, of which two corresponded to the cloned resistance genes Yr7 and Yr5/YrSp.


Author(s):  
Conceição Gomes, Ana Sofia Almeida, José Coutinho, Rita Costa, Nuno Pinheiro ◽  
João Coco, Armindo Costa, Ana Sofia Bagulho and Benvindo Maçãs

Yellow rust caused by Puccinia striiformis f. sp. tritici, is a foliar wheat disease that cause significant yield losses in Portuguese bread and durum wheat yield, mainly in recent years. The strategies to disease control include cultural practices (crop rotation, use of balanced fertilizers, framework of planting dates), use of resistant varieties and fungicide application. The concern of modern plant breeding has been the improvement of new varieties with escape behavior to diseases and/or genetic resistance, but currently, the use of chemical produts offers a pratical and rapid response solution to combat rust outbreaks. In the present study, field experiments were conducted from 2013/2014 to 2016/2017 growing seasons to evaluate: 1) resistance levels against yellow rust in some bread and durum wheat varieties widely used by Portuguese farmers; 2) the opportunity of application of fungicide in the control of Puccinia striiformis in two stages of plant development; 3) gains obtained in each situation in yield and thousand kernel weight (TKW) compared to the control without fungicide application. This study allows to conclude that the need to use fungicide sprays it´s related not only on the carry over of rust inoculum in crop, but also of the races/strains of P. striiformis occurring in a region, the crop growth stage at time of symptom appearance and on variety level of resistance.


2021 ◽  
Author(s):  
Laura Bouvet ◽  
Simon Berry ◽  
Paul Fenwick ◽  
Sarah Holdgate ◽  
Ian J Mackay ◽  
...  

Yellow rust (YR), or stripe rust, is a fungal infection of wheat (Triticum aestivum L.) caused by the pathogen Puccinia striiformis f. sp. tritici (Pst). While much research has focused on YR infection of wheat leaves, we are not aware of reports investigating the genetic control of YR resistance in other wheat structures, such as the ears. Here we use an eight-founder population to undertake genetic analysis of glume YR infection in wheat ears. Five quantitative trait loci (QTL) were identified, each explaining between 3.4% and 6.8% of the phenotypic variation. Of these, three (QYrg.niab-2D.1, QYrg.niab-4D.1 and QYrg.niab-5A.1) co-located with QTL for leaf YR resistance previously identified in the same population. Additional leaf YR resistance QTL previously identified in the population were not detected as controlling glume resistance, with the remaining two glume YR QTL linked to genetic loci controlling flowering time. The first, QYrg.niab-2D. 1, mapped to the major flowering time locus Photoperiod-D1 (Ppd-D1), with the early-flowering allele from the founder Soissons conferring reduced glume YR resistance. The second, QYrg.niab-4A.1, was identified in one trial only, and was located close to a flowering time QTL. This indicates earlier flowering results in increased glume YR susceptibility, likely due to exposure of tissues during environmental conditions more favourable for Pst infection. Collectively, our results provide first insights into the genetic control of YR resistance in glumes, ontrolled by subsets of QTL for leaf YR resistance and flowering time. This work provides specific genetic targets for the control of YR resistance in both the leaves and the glumes, and may be especially relevant in Pst-prone agricultural environments where earlier flowering is favoured.


1970 ◽  
Vol 6 (1) ◽  
pp. 99-106 ◽  
Author(s):  
S Ali ◽  
SJA Shah ◽  
K Maqbool

Durable resistance based on partial resistance is an important and effective way to combat the problem of yellow rust (Puccinia striiformis West. tritici). Field-based assessment of partial resistance is crucial in developing countries for the breeders, dealing with hundreds of lines at a time. The present experiment was carried out during 2005-2006 to reveal variability for field based-partial resistance to yellow rust among 20 wheat breeding lines grown at Nuclear Institute for Food and Agriculture, Peshawar, along with ‘Morocco' as susceptible check. Partial resistance was assessed through the infection type, final rust severity (FRS), area under rust progress curve (AURPC), infection rate (IR) and co-efficient of infection (CI). Cluster analysis of the 20 wheat lines revealed two main groups/clusters along Morocco as a separate cluster. Based on overall parameters, these lines were grouped into two clusters. Nine lines were grouped in one cluster, while remaining 11 lines were clustered in another group. Similarly, cluster analysis based on partial resistance parameters also resulted in two groups for the tested lines along with Morocco as a separate line. The first cluster included the lines considered as moderately slow yellow rusting lines while those of later group were marked as better slow rusting lines. Strong association was found between co-efficient of infection (CI) with both FRS and AURPC, while it was too weaker with IR. The present study revealed that the lines were having enough diversity regarding slow rusting behavior and yellow rust resistance, ranging from immunity to partial resistant lines. Similarly, CI, FRS and AURPC are suggested to be useful for assessment of partial resistance to yellow rust. Key words: Wheat, yellow rust, partial resistance, field-based assessment. doi:10.3329/jard.v6i1.1663 J Agric Rural Dev 6(1&2), 99-106, June 2008


Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 499-504 ◽  
Author(s):  
A. H. Yahyaoui ◽  
M. S. Hakim ◽  
M. El Naimi ◽  
N. Rbeiz

Virulence-avirulence phenotypes of Puccinia striiformis isolates collected in Lebanon and Syria were determined on seedlings of the wheat-yellow rust differential genotypes. We found 25 and 11 physiologic races over 6 years (1994 to 1999) in Syria and Lebanon, respectively. The composition of physiologic races found in Syria and Lebanon differed greatly between 1994 and 1999. Races identified in 1999, such as 230E150 and 230E134, have wider spectra of virulence on resistant genotypes than races collected in 1994. In Lebanon, three races were found in 1994 compared with six races in 1999. Yellow rust differential genotypes were used in a trap nursery to monitor yellow rust populations under natural conditions. Races identified from cultivars in the trap nursery in Syria and Lebanon, and from land race cultivars in Iraq, were recovered among the races identified from farm fields. Yellow rust samples were collected from Yemen, and none of the races identified from Yemen samples were identical to those in Syria and Lebanon. Virulence frequencies in the yellow rust population on the differential genotypes tested in the trap nurseries were above 70% for some resistance genes. Yellow rust populations in Syria and Lebanon have diverse virulence phenotypes. P. striiformis populations appear to be changing over, and this would be an important consideration for wheat breeding programs in the region.


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.


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


Plant Disease ◽  
2015 ◽  
Vol 99 (6) ◽  
pp. 754-760 ◽  
Author(s):  
D. J. Han ◽  
Q. L. Wang ◽  
X. M. Chen ◽  
Q. D. Zeng ◽  
J. H. Wu ◽  
...  

Stripe rust, caused by Puccinia striiformis f. tritici, is one of the most destructive diseases of wheat in the world. The Sichuan Basin is one of the most important regions of wheat production and stripe rust epidemics in China. Stripe rust resistance gene Yr26 (the same gene as Yr24) has been widely used in wheat breeding programs and in many cultivars grown in this region since the gene was discovered in the early 1990s. Virulence to Yr26 has increased in frequency since its first detection in 2008. The objective of this study was to assess the vulnerability of the wheat cultivars and breeding lines in the Sichuan Basin to Yr26-virulent races. In total, 85 wheat accessions were tested with Yr26-avirulent races CYR32, CYR33, and Su11-4 and two Yr26-virulent races, V26/CM42 and V26/Gui22. DNA markers for Yr26 were used to determine the presence and absence of Yr26 in the wheat accessions. Of the 85 wheat accessions, only 5 were resistant and 19 susceptible to all races tested, and the remaining 61 were resistant to at least one or more races tested in seedling stage. In all, 65 (76.5%) accessions were susceptible to the emerging Yr26-virulent race V26/Gui22. In field tests, susceptible accessions increased from 31.8% in a nursery inoculated with predominant and Yr26-avirulent races to 61.2% in the nursery inoculated with the predominant races mixed with V26/Gui22. Based on the results of the molecular marker and race tests, 33 (38.8%) accessions were determined to have Yr26, showing that the Yr26 virulence is a major threat to wheat production in the Sichuan Basin and potentially in other regions of China.


Plant Disease ◽  
2018 ◽  
Vol 102 (3) ◽  
pp. 483-487 ◽  
Author(s):  
Bing Bing Bai ◽  
Tai Guo Liu ◽  
Bo Liu ◽  
Li Gao ◽  
Wan Quan Chen

In total, 13 commercial wheat cultivars around China and four races of Puccinia striiformis f. sp. tritici (namely, CYR32, CYR33, G22-9, and G22-14) were employed for a test of relative parasitic fitness (RPF) using the drop method. The RPF values were measured, including the urediniospore germination rate, the latent period, the uredinial length, the uredinial density, the infection area, the sporulation intensity, the lesion expansion speed, and the sporulation period. The results indicated that the parameters of relative parasitic fitness of the four P. striiformis f. sp. tritici races on the 13 wheat cultivars were significantly different (P = 0.00) in sporulation intensity, lesion expansion speed, uredinial length, sporulation period, uredinial density, and latent period. The urediniospore germination rates of the four P. striiformis f. sp. tritici races for the test were significantly different (P = 0.00), whereas no correlation with the different cultivars was observed (P = 1.00). The infection areas of the tested races on the different cultivars were significantly different (P = 0.00) but there were no obvious manifestations among the various races (P = 0.20). Principal component analysis (PCA) showed that the sporulation intensity represented sporulation capacity and scalability, the latent period indicated infection ability, and the urediniospore germination rate represented urediniospore vigor, all of which fully contributed to the RPF in the interaction of the four races and 13 wheat cultivars, which was calculated by the following formula: RPF = (sporulation intensity × urediniospore germination rate)/latent period. The sporulation and infection of G22-9 on the 13 large-scale cultivated cultivars were the highest, and the RPF of G22-9 was higher than that of the predominant races, CYR32 and CYR33. This result suggested that G22-9 could become a new predominant race and potentially cause epidemics of wheat stripe rust in China. To prevent potential epidemics, susceptible wheat cultivars should be withdrawn from production and breeding programs should reduce the use of Yr10 and Yr26 and use other more effective resistance genes in combination with nonrace-specific resistance for developing wheat cultivars with durable resistance to stripe rust.


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