stem rust
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Author(s):  
Mônica Bossardi Coelho ◽  
Sandra Mansur Scagliusi ◽  
Brent Mccallum ◽  
Colin W. Hiebert ◽  
Márcia Soares Chaves ◽  
...  

2021 ◽  
Author(s):  
Guotai Yu ◽  
Oadi Matny ◽  
Nicolas Champouret ◽  
Burkhard Steuernagel ◽  
Matthew J. Moscou ◽  
...  

Abstract The wild relatives and progenitors of wheat have been widely used as sources of disease resistance (R) genes. Molecular identification and characterization of these R genes facilitates their manipulation and tracking in breeding programmes. We developed a reference-quality genome assembly of the wild diploid wheat relative Aegilops sharonensis and used positional mapping, mutagenesis, RNA-Seq and transgenesis to identify the stem rust resistance gene Sr62, which was also transferred to common wheat. This gene encodes a tandem kinase, homologues of which exist across multiple taxa in the plant kingdom. Stable Sr62 transgenic wheat lines showed high levels of resistance against diverse isolates of the stem rust pathogen, highlighting the utility of Sr62 for deployment as part of a polygenic stack to maximize the durability of stem rust resistance.


2021 ◽  
Vol 26 (2(49)) ◽  
pp. 51-72
Author(s):  
I. I. Motsnyi ◽  
T. P. Nargan ◽  
M. Yu. Nakonechnyi ◽  
S. Ph. Lyfenko ◽  
О. О. Molodchenkova ◽  
...  

Introduction. The global climate change conduces spreading of main diseases of winter bread wheat (Triticum aestivum L.) and increases the yield losses caused by both these diseases and drought. Preventing the devastating impact of these factors on the yield depends on development of donors carrying the resistance genes. Aim. The diversity of new introgression wheat lines derived from complex interspecies crosses was evaluated for resistance to widespread diseases, drought and other agricultural traits. Methods. The trial was conducted consecutively during two vegetative periods (2018-2019 and 2019-2020) on the black earth area under the arid system in a control nursery design. Genetic material includes seventy-eight introgression wheat lines of different origin with two check cultivars for the arid climate zone of Ukraine. The data on nine agronomic (quantitative scores) and five plant pathological (point scores) traits were collected and subjected to both variance and correlation analysis to comprehend the contribution of the factors towards general diversity and connections between the characters. Results. Most lines were resistant to rust species due to the successful introgression of alien Lr, Yr and Sr genes from all sources involved in hybridization. High long-term resistance to stem rust was observed mainly among the derivatives of the collection sample H74/90-245 from Bulgaria, whose genetic background was favorable for generating a positive effect of 1BL.1RS translocation on both productive and adaptive traits in southern Ukraine and the ability to combine with other resistance genes. The yield traits did not correlate with the resistance to diseases except stem rust (Rsp = 0.34**) and Septoria blight (Rsp = −0.23*). Resistance to stem rust correlated with the grain and protein yield, test weight and flour density, which may be due to the presence of translocation 1BL.1RS. Negative correlation was observed between quality traits and grain yield, but quality traits mainly positively correlated with each other. The plant height had the highest contribution to grain yield followed by volume of 1000 kernels and WTK. Conclusions. The introgression lines were found to be diverse and potential for use in the wheat improvement programs for resistance to the diseases or drought in Southern Ukraine.


Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 74
Author(s):  
Alibek Zatybekov ◽  
Yuliya Genievskaya ◽  
Aralbek Rsaliyev ◽  
Akerke Maulenbay ◽  
Gulbahar Yskakova ◽  
...  

In recent years, leaf rust (LR) and stem rust (SR) have become a serious threat to bread wheat production in Kazakhstan. Most local cultivars are susceptible to these rusts, which has affected their yield and quality. The development of new cultivars with high productivity and LR and SR disease resistance, including using marker-assisted selection, is becoming an important priority in local breeding projects. Therefore, the search for key genetic factors controlling resistance in all plant stages, including the seedling stage, is of great significance. In this work, we applied a genome-wide association study (GWAS) approach using 212 local bread wheat accessions that were phenotyped for resistance to specific races of Puccinia triticina Eriks. (Pt) and Puccinia graminis f. sp. tritici (Pgt) at the seedling stages. The collection was genotyped using a 20 K Illumina iSelect SNP assay, and 11,150 polymorphic SNP markers were selected for the association mapping. Using a mixed linear model, we identified 11 quantitative trait loci (QTLs) for five out of six specific races of Pt and Pgt. The comparison of the results from this GWAS with those from previously published work showed that nine out of eleven QTLs for LR and SR resistance had been previously reported in a GWAS study at the adult plant stages of wheat growth. Therefore, it was assumed that these nine common identified QTLs were effective for all-stage resistance to LR and SR, and the two other QTLs appear to be novel QTLs. In addition, five out of these nine QTLs that had been identified earlier were found to be associated with yield components, suggesting that they may directly influence the field performance of bread wheat. The identified QTLs, including novel QTLs found in this study, may play an essential role in the breeding process for improving wheat resistance to LR and SR.


2021 ◽  
Author(s):  
Rohit Mago ◽  
Chunhong Chen ◽  
Xiaodi Xia ◽  
Alex Whan ◽  
Kerrie Forrest ◽  
...  

Abstract An F3 population from a Glossy Huguenot (GH)/Bansi cross used in a previous Australian study was advanced to F6 for molecular mapping of adult plant stem rust resistance. Maturity differences among F6 lines confounded assessments of stem rust response. GH was crossed with a stem rust susceptible F6 recombinant inbred line (RIL), GHB14 (M14), with similar maturity and an F6:7 population was developed through single seed descent method. F7 and F8 RILs were tested along with the parents at different locations. The F6 individual plants and both parents were genotyped using the 90K single nucleotide polymorphism (SNP) wheat array. Stem rust resistance QTL on the long arms of chromosomes 1B (QSrGH.cs-1BL) and 2A (QSrGH.cs-2AL) were detected. QSrGH.cs-1BL and QSrGH.cs-2AL were both contributed by GH and explained 22% and 18% adult plant stem rust response variation, respectively, among GH/M14 RIL population. RILs carrying combinations of these QTL reduced more than 14% stem rust severity compared to those that possessed QSrGH.cs-1BL and QSrGH.cs-2AL individually. QSrGH.cs1BL was demonstrated to be the same as Sr58/Lr46/Yr29/Pm39 through marker genotyping. Lines lacking QSrGH.cs-1BL were used to Mendelise QSrGH.cs-2AL. Based on genomic locations of previously catalogued stem rust resistance genes and the QSrGH.cs-2AL map, it appeared to represent a new APR locus and was permanently named Sr63. SNP markers associated with Sr63 were converted to kompetetive allele specific PCR (KASP) assays and were validated on a set of durum cultivars.


2021 ◽  
Vol 25 (7) ◽  
pp. 740-745
Author(s):  
E. S. Skolotneva ◽  
V. N. Kelbin ◽  
V. P. Shamanin ◽  
N. I. Boyko ◽  
V. A. Aparina ◽  
...  

Present-day wheat breeding for immunity exploits extensively closely related species from the family Triticeae as gene donors. The 2NS/2AS translocation has been introduced into the genome of the cultivated cereal Triticum aestivum from the wild relative T. ventricosum. It contains the Lr37, Yr17, and Sr38 genes, which support seedling resistance to the pathogens Puccinia triticina Eriks., P. striiformis West. f. sp. tritici, and P. graminis Pers. f. sp. tritici Eriks. & E. Henn, which cause brown, yellow, and stem rust of wheat, respectively. This translocation is present in the varieties Trident, Madsen, and Rendezvous grown worldwide and in the Russian varieties Morozko, Svarog, Graf, Marquis, and Homer bred in southern regions. However, the Sr38 gene has not yet been introduced into commercial varieties in West Siberia; thus, it remains of practical importance for breeding in areas where populations of P. graminis f. sp. tritici are represented by avirulent clones. The main goal of this work was to analyze the frequency of clones (a)virulent to the Sr38 gene in an extended West Siberian collection of stem rust agent isolates. In 2019–2020, 139 single pustule isolates of P. graminis f. sp. tritici were obtained on seedlings of the standard susceptible cultivar Khakasskaya in an environmentally controlled laboratory (Institute of Cytology and Genetics SB RAS) from samples of urediniospores collected on commercial and experimental bread wheat fields in the Novosibirsk, Omsk, Altai, and Krasnoyarsk regions. By inoculating test wheat genotypes carrying Sr38 (VPM1 and Trident), variations in the purity of (a)virulent clones were detected in geographical samples of P. graminis f. sp. tritici. In general, clones avirulent to Sr38 constitute 60 % of the West Siberian fungus population, whereas not a single virulent isolate was detected in the Krasnoyarsk collection. The Russian breeding material was screened for sources of the stem rust resistance gene by using molecular markers specific to the 2NS/2AS translocation. A collection of hybrid lines and varieties of bread spring wheat adapted to West Siberia (Omsk SAU) was analyzed to identify accessions promising for the region. The presence of the gene was postulated by genotyping with specific primers (VENTRIUP-LN2) and phytopathological tests with avirulent clones of the fungus. Dominant Sr38 alleles were identified in Lutescens 12-18, Lutescens 81-17, Lutescens 66-16, Erythrospermum 79/07, 9-31, and 8-26. On the grounds of the composition of the West Siberian P. graminis f. sp. tritici population, the Sr38 gene can be considered a candidate for pyramiding genotypes promising for the Novosibirsk, Altai, and Krasnoyarsk regions. 


2021 ◽  
Vol 25 (7) ◽  
pp. 723-731
Author(s):  
I. F. Lapochkina ◽  
N. R. Gainullin ◽  
O. A. Baranova ◽  
N. M. Kovalenko ◽  
L. A. Marchenkova ◽  
...  

An original initial material of spring and winter bread wheat with group resistance to stem and leaf rust was developed using new donors of resistance to stem rust: winter soft wheat GT 96/90 (Bulgaria) and accession 119/4-06rw with genetic material of the species Triticum migushovae and (Aegilops speltoides and Secale cereale), respectively, a line of spring wheat 113/00i-4 obtained using the species Ae. triuncialis and T. kiharae, as well as spring accession 145/00i with genetic material of the species Ae. speltoides resistant to leaf rust. The transfer of effective Sr-genes to progeny was monitored using molecular markers. New lines underwent a field assessment of resistance to leaf and stem rust in the epiphytotic development of diseases in the Central Region of the Russian Federation, as well as in the North Caucasus and Western Siberia, and showed high resistance to these pathogens. Fourteen genotypes of spring wheat with group resistance to these diseases and parental forms that participated in the origin of the lines were evaluated for resistance to spot blotch (Cochliobolus sativus) and tan spot (Pyrenophora tritici-repentis) using isolates from Kazakhstan and Omsk in laboratory conditions. A highly resistant parental form of winter soft wheat from “Arsenal” collection 119/4-06rw (wheat-Ae. speltoides-rye hybrid 2n = 42) with group resistance to two spots, four medium-resistant genotypes to both isolates of tan spot from Kazakhstan and Omsk populations of the pathogen, as well as genotypes resistant to the Omsk isolate of P. triticirepentis (parental form 113/00i-4 and lines 1-16i, 6-16i, 9-16i) were isolated. Among the lines of winter wheat, four were identified with group resistance to spot blotch and tan spot. Additionally, the stress resistance of the lines to NaCl salinization and prolonged flooding of seeds with water was evaluated at the early stages of ontogenesis in laboratory conditions. Lines 33-16i, 37-16i, 32-16i and 9-16i showed a high ability to withstand excess moisture. Lines 33-16i, 37-16i, 32-16i and 3-16i were characterized by high salt tolerance, exceeding the average of 49.7 %. Among the winter genotypes, lines were identified with increased resistance to hypoxia (37-19w, 32-19w, 16-19w, 90-19w) and with increased salt tolerance (20-19w, 9-19w, 37-19w, 90-19w), significantly exceeding the standard cv. Moskovskaya 39. The listed lines are of interest as sources of resistance to anaerobic and salt stress, as well as donors of resistance to a group of fungal diseases: leaf and stem rust and tan spot. We attribute the increased level of resistance of the new initial material to the presence of alien translocations in the original parental forms involved in the origin of the lines.


2021 ◽  
Vol 20 (1) ◽  
pp. 1-27
Author(s):  
Bosco Chemayek ◽  
Urmil K. Bansal ◽  
Hanif Miah ◽  
William W. Wagoire ◽  
Harbans S. Bariana

The objective of this study was to assess diversity for stem rust and stripe rust resistance in an international wheat screening nursery under greenhouse conditions using pathotypes with known avirulence/ virulence profiles. A set of 95 entries of an international wheat screening nursery collected from material generated by staff of the International Maize and Wheat Improvement Centre (CIMMYT) was tested against seven Australian Pgt and five Pst pathotypes through artificial inoculation under the greenhouse conditions using standard procedures. Ten all-stage stem rust resistance genes (Sr8a, Sr8b, Sr9b, Sr12, Sr17, Sr23, Sr24, Sr30, Sr31 and Sr38) and seven all-stage stripe rust resistance genes (Yr3, Yr4, Yr6, Yr9, Yr17, Yr27 and Yr34) were postulated either singly or in combinations based on seedling responses of test entries against pathotypes differing in virulence for commonly deployed genes. Sr30 and Sr38 were the most common stem rust resistance genes in this nursery. The Sr38-linked stripe rust resistance gene Yr17 was present in high proportion. The presence of rust resistance genes Sr24, Sr31/Yr9, Sr38/Yr17 and Yr4 were confirmed using the closely linked molecular markers. The adult plant resistance (APR) genes Sr2 and Lr34/Yr18/Sr57 were detected using linked molecular markers csSr2 and csLV34, respectively. Genotypes carrying combinations of stem rust and stripe rust resistance were identified for use as donor sources in breeding programs.


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