Description of Wheat Rusts and Their Virulence Variations Determined through Annual Pathotype Surveys and Controlled Multi-Pathotype Tests

Wheat production started in Australia around 1788 using early maturing varieties adapted to Australian conditions that were able to escape diseases as well as moisture stress conditions. Wheat production is concentrated on mainland Australia in a narrow crescent land considered as the wheat belt occupying an area of about 13.9 million hectares. Rusts are the most important production constraints to wheat production in the world and Australia causing significant yield losses and decreased the qualities of grains. Wheat is affected by three different types of rust diseases: leaf rust, stripe rust or yellow rust, and stem rust. Each species of the rust pathogen has many races or pathotypes that parasitize only on certain varieties of host species, which can only be traced and identified by differential cultivars. Pathotype surveillance is the basis for information on the virulence or pathogenic variations existing in a particular country or wheat growing region of the world. Studies in pathotype variation are conducted in controlled environments using multi-pathotype tests. The currently cultivated commercial wheat varieties of Australia possess leaf rust resistant genes: Lr1, Lr3a, Lr13, Lr13+, Lr14a, Lr17a, Lr17b, Lr20, Lr23, Lr24, Lr26, Lr27, Lr31, Lr34, Lr37, and Lr46; stem rust resistance genes: Sr2, Sr5, Sr8a, Sr8b, Sr9b, Sr9g, Sr11, Sr12, Sr13, Sr15, Sr17, Sr22, Sr24, Sr26, Sr30, Sr36, Sr38, and Sr57; and stripe rust resistance genes: Yr4, Yr9, Yr17, Yr18, Yr27, and Yr33. This paper discusses the historical and current significance of rusts to wheat production in the world with particular reference to Australia viz-a-viz detail description of each of the three rusts and their respective virulence variations through the resistance genes deployed in the commercial cultivars.

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Molecular Marker Based Design for Breeding Wheat Lines with Multiple Resistance and Superior Quality

Plant Disease ◽

10.1094/pdis-02-20-0420-re ◽

2020 ◽

Vol 104 (10) ◽

pp. 2658-2664

Author(s):

Tao Liu ◽

George Fedak ◽

Lianquan Zhang ◽

Rangrang Zhou ◽

Dawn Chi ◽

...

Keyword(s):

Stripe Rust ◽

Resistance Genes ◽

High Resistance ◽

Stem Rust ◽

Rust Resistance ◽

Stripe Rust Resistance ◽

Multiple Resistance ◽

Wheat Stem Rust ◽

Wheat Production ◽

Rust Resistance Genes

There has not been a major wheat stem rust epidemic worldwide since the 1970s, but the emergence of race TTKSK of Puccinia graminis f. sp. tritici in 1998 presented a great threat to the world wheat production. Single disease-resistance genes are usually effective for only several years before the pathogen changes genetically to overcome the resistance. Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is one of the most common and persistent wheat diseases worldwide. The development of varieties with multiple resistance is the most economical and effective strategy for preventing stripe rust and stem rust, the two main rust diseases constraining wheat production. Plateau 448 has been widely used in the spring wheat growing region in northwest China, but it has become susceptible to stripe rust and is susceptible to TTKSK. To produce more durable resistance to race TTKSK as well as to stripe rust, four stem rust resistance genes (Sr33, Sr36, Sr-Cad, and Sr43) and three stripe rust resistance genes (Yr5, Yr18, and Yr26) were simultaneously introgressed into Plateau 448 to improve its stem rust (Ug99) and stripe rust resistance using a marker-assisted backcrossing strategy combined with phenotypic selection. We obtained 131 BC1F5 lines that pyramided two to four Ug99 resistance genes and one to two Pst resistance genes simultaneously. Thirteen of these lines were selected for their TTKSK resistance, and all of them exhibited near immunity or high resistance to TTKSK. Among the 131 pyramided lines, 95 showed high resistance to mixed Pst races. Nine lines exhibited not only high resistance to TTKSK and Pst but also better agronomic traits and high-molecular-weight glutenin subunit compositions than Plateau 448.

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Development of a PCR Assay and Marker-Assisted Transfer of Leaf Rust and Stripe Rust Resistance Genes Lr57 and Yr40 into Hard Red Winter Wheats

Crop Science ◽

10.2135/cropsci2008.03.0143 ◽

2009 ◽

Vol 49 (1) ◽

pp. 120-126 ◽

Cited By ~ 11

Author(s):

Vasu Kuraparthy ◽

Shilpa Sood ◽

Deven R. See ◽

Bikram S. Gill

Keyword(s):

Leaf Rust ◽

Stripe Rust ◽

Resistance Genes ◽

Rust Resistance ◽

Stripe Rust Resistance ◽

Pcr Assay ◽

Rust Resistance Genes

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Wheat Breeding for Disease Resistance: Review

Open Access Journal of Microbiology & Biotechnology ◽

10.23880/oajmb-16000142 ◽

2019 ◽

Vol 4 (2) ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Gadisa Alemu

Keyword(s):

Disease Resistance ◽

Leaf Rust ◽

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Yellow Rust ◽

Wheat Breeding ◽

High Yield ◽

Breeding Programs ◽

Rust Resistance Genes

Breeding for disease resistance is a central focus of plant breeding programs, as any successful variety must have the complete package of high yield, disease resistance, agronomic performance, and end - use quality. Wheat breeding is focused on high yield, pathogen resistance and abiotic stress tolerance. Among diseases of wheat yellow rust, stem rust, and leaf rust are the most damaging diseases of wheat and other small grain cereals . Disease resistance in wheat breeding with one exception, the diseases of wheat that is important because of their effect on yield. Resistance to all diseases together can is important to avoid an unexpected loss in effectiveness of the resistance of a cu ltivar to a major disease. The genetic resistance to stem rust, leaf rust and yellow rust can be characterized as qualitative and quantitative resistances. Vertical resistance is specific to pathogen isolates based on single or very few genes. Race - specifi c is used to describe resistance that interacts differentially with pathogen races. Quantitative resistance is defined as resistance that varies in continuous way between the various phenotypes of the host population, from almost imperceptible to quite str ong. With the need to accelerate the development of improved varieties, genomics - assisted breeding is becoming an important tool in breeding programs. With marker - assisted selection, there has been success in breeding for disease resistance. Generally, bre eding programs have successfully implemented molecular markers to assist in the development of cultivars with stem, leaf and stripe rust resistance genes. When new rust resistance genes are to be deployed in wheat breeding programs, it unfortunately takes several years before the new sources of resistance will become available in commercial wheat cultivars. This is due to the long process involved in the establishment of pure breeding wheat lines. Biotechnology based techniques are available to accelerate t he breeding process via doubled haploid production.

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Genome-Wide Association Studies Reveal All-Stage Rust Resistance Loci in Elite Durum Wheat Genotypes

Frontiers in Plant Science ◽

10.3389/fpls.2021.640739 ◽

2021 ◽

Vol 12 ◽

Author(s):

Meriem Aoun ◽

Matthew N. Rouse ◽

James A. Kolmer ◽

Ajay Kumar ◽

Elias M. Elias

Keyword(s):

Durum Wheat ◽

Leaf Rust ◽

Stripe Rust ◽

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Genome Wide Association ◽

Genome Wide ◽

Rust Pathogen ◽

Rust Resistance Genes

Leaf rust, caused by Puccinia triticina (Pt), stripe rust caused by Puccinia striiformis f. sp. tritici (Pst), and stem rust caused by Puccinia graminis f. sp. tritici (Pgt) are major diseases to wheat production globally. Host resistance is the most suitable approach to manage these fungal pathogens. We investigated the phenotypic and genotypic structure of resistance to leaf rust, stem rust, and stripe rust pathogen races at the seedling stage in a collection of advanced durum wheat breeding lines and cultivars adapted to Upper Mid-West region of the United States. Phenotypic evaluation showed that the majority of the durum wheat genotypes were susceptible to Pt isolates adapted to durum wheat, whereas all the genotypes were resistant to common wheat type-Pt isolate. The majority of genotypes were resistant to stripe rust and stem rust pathogen races. The durum panel genotyped using Illumina iSelect 90 K wheat SNP assay was used for genome-wide association mapping (GWAS). The GWAS revealed 64 marker-trait associations (MTAs) representing six leaf rust resistance loci located on chromosome arms 2AS, 2AL, 5BS, 6AL, and 6BL. Two of these loci were identified at the positions of Lr52 and Lr64 genes, whereas the remaining loci are most likely novel. A total of 46 MTAs corresponding to four loci located on chromosome arms 1BS, 5BL, and 7BL were associated with stripe rust response. None of these loci correspond to designated stripe rust resistance genes. For stem rust, a total of 260 MTAs, representing 22 loci were identified on chromosome arms 1BL, 2BL, 3AL, 3BL, 4AL, 5AL, 5BL, 6AS, 6AL, 6BL, and 7BL. Four of these loci were located at the positions of known genes/alleles (Sr7b, Sr8155B1, Sr13a, and Sr13b). The discovery of known and novel rust resistance genes and their linked SNPs will help diversify rust resistance in durum wheat.

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Transfer of Leaf Rust and Stripe Rust Resistance Genes Lr62 and Yr42 from Aegilops neglecta Req. ex Bertol. to Common Wheat

Crop Science ◽

10.2135/cropsci2008.06.0317 ◽

2009 ◽

Vol 49 (3) ◽

pp. 871-879 ◽

Cited By ~ 45

Author(s):

Francois Marais ◽

Ansie Marais ◽

Brent McCallum ◽

Zacharias Pretorius

Keyword(s):

Leaf Rust ◽

Common Wheat ◽

Stripe Rust ◽

Resistance Genes ◽

Rust Resistance ◽

Stripe Rust Resistance ◽

Rust Resistance Genes

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Aegilops umbellulata introgression carrying leaf rust and stripe rust resistance genes Lr76 and Yr70 located to 9.47-Mb region on 5DS telomeric end through a combination of chromosome sorting and sequencing

Theoretical and Applied Genetics ◽

10.1007/s00122-019-03514-x ◽

2020 ◽

Vol 133 (3) ◽

pp. 903-915 ◽

Cited By ~ 3

Author(s):

Mitaly Bansal ◽

Nikolai M. Adamski ◽

Puneet Inder Toor ◽

Satinder Kaur ◽

István Molnár ◽

...

Keyword(s):

Leaf Rust ◽

Stripe Rust ◽

Resistance Genes ◽

Rust Resistance ◽

Stripe Rust Resistance ◽

Chromosome Sorting ◽

Aegilops Umbellulata ◽

Rust Resistance Genes

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Leaf rust and stripe rust resistance genes Lr54 and Yr37 transferred to wheat from Aegilops kotschyi

Plant Breeding ◽

10.1111/j.1439-0523.2005.01116.x ◽

2005 ◽

Vol 124 (6) ◽

pp. 538-541 ◽

Cited By ~ 47

Author(s):

G. F. Marais ◽

B. McCallum ◽

J. E. Snyman ◽

Z. A. Pretorius ◽

A. S. Marais

Keyword(s):

Leaf Rust ◽

Stripe Rust ◽

Resistance Genes ◽

Rust Resistance ◽

Stripe Rust Resistance ◽

Rust Resistance Genes

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A walk on the wild side: mining wild wheat and barley collections for rust resistance genes

Australian Journal of Agricultural Research ◽

10.1071/ar07123 ◽

2007 ◽

Vol 58 (6) ◽

pp. 532 ◽

Cited By ~ 74

Author(s):

Brian J. Steffenson ◽

Pablo Olivera ◽

Joy K. Roy ◽

Yue Jin ◽

Kevin P. Smith ◽

...

Keyword(s):

Leaf Rust ◽

Stripe Rust ◽

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Wild Barley ◽

Stem Rust Resistance ◽

Dart Markers ◽

Wide Range ◽

Rust Resistance Genes

Leaf rust, stem rust, and stripe rust are among the most important diseases of wheat and barley worldwide and are best controlled using genetic resistance. To increase the diversity of rust resistance in wheat and barley, a project was initiated to identify and characterise rust resistance genes from the wild species of Aegilops sharonensis (Sharon goatgrass) and Hordeum vulgare ssp. spontaneum (wild barley), respectively. One hundred and two accessions of Sharon goatgrass from Israel and 318 Wild Barley Diversity Collection (WBDC) accessions from the Fertile Crescent, Central Asia, North Africa, and the Caucasus region were evaluated for resistance to leaf rust, stem rust, and/or stripe rust. Sharon goatgrass exhibited a wide range of infection types (ITs) in response to leaf rust, stem rust, and stripe rust. The percentage of resistant accessions in Sharon goatgrass was 58.8–78.4% for leaf rust, 11.8–69.6% for stem rust, and 46.1% for stripe rust, depending on the race used and the plant growth stage. Genetic studies with Sharon goatgrass revealed oligogenic resistance to leaf rust and stem rust. Wild barley also exhibited a wide range of ITs to leaf rust and stem rust; however, the overall frequency of resistance was lower than for Sharon goatgrass. The percentage of resistant accessions in wild barley was 25.8% for leaf rust and 5.7–20.1% for stem rust, depending on the race used. Resistance to the new virulent stem rust race TTKS (i.e. Ug99), present in eastern Africa, was found in both Sharon goatgrass (70% of accessions) and wild barley (25% of 20 accessions tested). Association mapping for stem rust resistance was applied in the WBDC using Diversity Arrays Technology (DArT) markers. Using the highly conservative P value threshold of 0.001, 14 and 15 significant marker associations were detected when the number of subpopulations (K value) was set for 10 and 8, respectively. These significant associations were in 9 and 8 unique chromosome bins, respectively. Two significant marker associations were detected for resistance to the wheat stem rust race MCCF in the same bin as the rpg4/Rpg5 complex on chromosome 7(5H). The presence of a major stem rust resistance gene in this bin on chromosome 7(5H) was validated in a bi-parental mapping population (WBDC accession Damon × cv. Harrington) constructed with DArT markers. The results from this study indicate that Sharon goatgrass and wild barley are rich sources of rust resistance genes for cultivated wheat and barley improvement, respectively, and that association mapping may be useful for positioning disease resistance genes in wild barley.

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