Identification of leaf rust resistance genes in selected egyptian wheat cultivars by molecular markers.
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ABSTRACT:
SUBMITTER: Imbaby IA
PROVIDER: S-EPMC3913395 | biostudies-other | 2014
REPOSITORIES: biostudies-other
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Project description:Wheat stem rust caused by Puccinia graminis f. sp. tritici Eriks. & E. Henn. (Pgt), is a major disease that has been effectively controlled using resistance genes. The appearance and spread of Pgt races such as Ug99, TKTTF, and TTTTF, which are virulent to most stem rust-resistant genes currently deployed in wheat breeding programs, renewed the interest in breeding cultivars resistant to wheat stem rust. It is therefore important to investigate the levels of resistance or vulnerability of wheat cultivars to Pgt races. Resistance to Pgt races 21C3CTHQM, 34MKGQM, and 34C3RTGQM was evaluated in 136 Chinese wheat cultivars at the seedling stage. A total of 124 cultivars (91.2%) were resistant to the three races. Resistance genes Sr2, Sr24, Sr25, Sr26, Sr31, and Sr38 were analyzed using molecular markers closely linked to them, and 63 of the 136 wheat cultivars carried at least one of these genes: 21, 25, and 28 wheat cultivars likely carried Sr2, Sr31, and Sr38, respectively. Cultivars "Kehan 3" and "Jimai 22" likely carried Sr25. None of the cultivars carried Sr24 or Sr26. These cultivars with known stem rust resistance genes provide valuable genetic material for breeding resistant wheat cultivars.
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Project description:Widening the genetic basis of leaf rust resistance is a primary objective of the global durum wheat breeding effort at the International Wheat and Maize Improvement Center (CIMMYT). Breeding programs in North America are following suit, especially after the emergence of new races of Puccinia triticina such as BBG/BP and BBBQD in Mexico and the United States, respectively. This study was conducted to characterize and map previously undescribed genes for leaf rust resistance in durum wheat and to develop reliable molecular markers for marker-assisted breeding. Four recombinant inbred line (RIL) mapping populations derived from the resistance sources Amria, Byblos, Geromtel_3 and Tunsyr_2, which were crossed to the susceptible line ATRED #2, were evaluated for their reaction to the Mexican race BBG/BP of P. triticina. Genetic analyses of host reactions indicated that leaf rust resistance in these genotypes was based on major seedling resistance genes. Allelism tests among resistant parents supported that Amria and Byblos carried allelic or closely linked genes. The resistance in Geromtel_3 and Tunsyr_2 also appeared to be allelic. Bulked segregant analysis using the Infinium iSelect 90K single nucleotide polymorphism (SNP) array identified two genomic regions for leaf rust resistance; one on chromosome 6BS for Geromtel_3 and Tunsyr_2 and the other on chromosome 7BL for Amria and Byblos. Polymorphic SNPs identified within these regions were converted to kompetitive allele-specific PCR (KASP) assays and used to genotype the RIL populations. KASP markers usw215 and usw218 were the closest to the resistance genes in Geromtel_3 and Tunsyr_2, while usw260 was closely linked to the resistance genes in Amria and Byblos. DNA sequences associated with these SNP markers were anchored to the wild emmer wheat (WEW) reference sequence, which identified several candidate resistance genes. The molecular markers reported herein will be useful to effectively pyramid these resistance genes with other previously marked genes into adapted, elite durum wheat genotypes.
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Project description:Stripe (yellow) rust, caused by Puccinia striiformis f.sp. tritici (Pst), is a fungal disease that presents one of the most serious threats to the wheat crops, causing severe yield losses worldwide, including Kazakhstan. The objectives of this study were to: (1) evaluate a winter wheat collection for stripe rust resistance during an adult plant growth stage, (2) identify the presence of selected Yr genes using linked molecular markers in wheat germplasm, (3) identify potentially useful resistant wheat genotypes among leading cultivars and advanced breeding lines. This study evaluated 70 winter wheat genotypes for stripe rust resistance. According to the field reactions, 42 entries (60%) had R or MR reactions including 27 breeding lines (38.6%) and 15 (21.4%) cultivars. Twenty-eight breeding lines/cultivars (40.0%) were susceptible in both years. According to the average coefficient of infection value (ACI) six genotypes were regarded as possessing high level of adult plant resistance. Cultivars/lines carrying Yr10 alone or in combination with other Yr resistance genes provided resistance to stripe rust. Eleven breeding lines showed <5% disease severity in both years. Linked marker analysis revealed the presence of several gene and gene complexes (Yr5, Yr10, Yr15, Yr17/Lr37/Sr38 and Yr18/Lr34). Among a collection of 70 winter wheat breeding lines and cultivars produced in Kazakhstan three stripe rust resistance genes (Yr10, Yr5 and Yr15) demonstrated high frequency occurrence (31.4%, 14.0% and 7.0%, respectively). The most abundant was gene Yr10 identified in 22 genotypes. It was followed by the Yr5 gene, which conferred resistance in 14 lines (20%) and Yr18 gene-11 lines (15.7%). Yr15 was identified in 7 genotypes. Yr17/Lr37/Sr38 gene complex was found in 2 entries. Among 70 evaluated germplasm sources, 42 disease resistant entries are potentially useful resistant wheat genotypes. These carriers of different Yr genes can be used directly in breeding programs to improve stripe rust resistance of winter wheat. Marker-assisted selection can be efficiently applied to develop wheat cultivars with effective gene combinations that would directly assist in developing durable resistance in Kazakhstan.
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Project description:Wheat is a vital dietary component for human health and widely consumed in the world. Wheat rusts are dangerous pathogens and contribute serious threat to its production. In present study, PCR-Based DNA Markers were employed to check the rust resistance genes among 20 wheat genotypes and 22 markers were amplified. NTSYS-pc 2.2 was used to calculate genetic diversity and Nei and Li's coefficients ranged from 0.55 to 0.95. Cluster analysis was obtained using UPGMA (Unweighted Pair Group Method of Arithmetic Average) algorithm. Maximum no. of genes (23) was amplified from TW-760010 genotype whereas minimum no of genes (14) were amplified from TW-76005 genotype. The data gained from present study open up new ways to produce new varieties by breeding rust resistant germplasm to avoid the economic and food loss and varieties with improved characteristics.
| S-EPMC4110429 | biostudies-other
Project description:Leaf rust, caused by Puccinia triticina (Ptr), is a significant disease of spring wheat spread in Kazakhstan. The development of resistant cultivars importantly requires the effective use of leaf rust resistance genes. This study aims to: (i) determine variation in Ptr population using races from the East Kazakhstan, Akmola, and Almaty regions of Kazakhstan; (ii) examine resistance during seedling and adult plant stages; and (iii) identify the sources of Lr resistance genes among the spring wheat collection using molecular markers. Analysis of a mixed population of Ptr identified 25 distinct pathotypes. Analysis of these pathotypes using 16 Thatcher lines that are near-isogenic for leaf rust resistance genes (Lr) showed different virulence patterns, ranging from least virulent "CJF/B" and "JCL/G" to highly virulent "TKT/Q". Most of the pathotypes were avirulent to Lr9, Lr19, Lr24, and Lr25 and virulent to Lr1, Lr2a, Lr3ka, Lr11, and Lr30. The Ptr population in Kazakhstan is diverse, as indicated by the range of virulence observed in five different races analyzed in this study. The number of genotypes showed high levels of seedling resistance to each of the five Ptr races, thus confirming genotypic diversity. Two genotypes, Stepnaya 62 and Omskaya 37, were highly resistant to almost all five tested Ptr pathotypes. Stepnaya 62, Omskaya 37, Avangard, Kazakhstanskaya rannespelaya, and Kazakhstanskaya 25 were identified as the most stable genotypes for seedling resistance. However, most of the varieties from Kazakhstan were susceptible in the seedling stage. Molecular screening of these genotypes showed contrasting differences in the genes frequencies. Among the 30 entries, 22 carried leaf rust resistance gene Lr1, and two had Lr9 and Lr68. Lr10 and Lr28 were found in three and four cultivars, respectively. Lr19 was detected in Omskaya 37. Two single cultivars separately carried Lr26 and Lr34, while Lr37 was not detected in any genotypes within this study. Field evaluation demonstrated that the most frequent Lr1 gene is ineffective. Kazakhstanskaya 19 and Omskaya 37 had the highest number of resistance genes: three and four Lr genes, respectively. Two gene combinations (Lr1, Lr68) were detected in Erythrospermum 35 and Astana. The result obtained may assist breeders in incorporating effective Lr genes into new cultivars and developing cultivars resistant to leaf rust.
| S-EPMC8309318 | biostudies-literature
Project description:Leaf rust and stripe rust are important wheat diseases worldwide causing significant losses where susceptible varieties are grown. Resistant cultivars offer long-term control and reduce the use of hazardous chemicals, which can be detrimental to both human health and the environment. Land races have been a valuable resource for mining new genes for various abiotic and biotic stresses including wheat rusts. Afghan wheat landrace "KU3067" displayed high seedling infection type (IT) for leaf rust and low IT for stripe rust; however, it displayed high levels of field resistance for both rusts when tested for multiple seasons against the Mexican rust isolates. This study focused on identifying loci-conferring seedling resistance to stripe rust, and also loci-conferring adult plant resistance (APR) against the Mexican races of leaf rust and stripe rust. A backcrossed inbred line (BIL) population advanced to the BC1F5 generation derived from the cross of KU3067 and Apav (triple rust susceptible line) was used for both, inheritance and QTL mapping studies. The population and parents were genotyped with Diversity Arrays Technology-genotyping-by-sequencing (DArT-Seq) and phenotyped for leaf rust and stripe rust response at both seedling and adult plant stages during multiple seasons in Mexico with relevant pathotypes. Mapping results identified an all-stage resistance gene for stripe rust, temporarily designated as YrKU, on chromosome 7BL. In total, six QTL-conferring APR to leaf rust on 1AS, 2AL, 4DL, 6BL, 7AL, and 7BL, and four QTL for stripe rust resistance on 1BS, 2AL, 4DL, and 7BL were detected in the analyses. Among these, pleiotropic gene Lr67/Yr46 on 4DL with a significantly large effect is the first report in an Afghan landrace-conferring resistance to both leaf and stripe rusts. QLr.cim-7BL/YrKU showed pleiotropic resistance to both rusts and explained 7.5-17.2 and 12.6-19.3% of the phenotypic variance for leaf and stripe rusts, respectively. QYr.cim-1BS and QYr.cim-2AL detected in all stripe environments with phenotypic variance explained (PVE) 12.9-20.5 and 5.4-12.5%, and QLr.cim-6BL are likely to be new. These QTL and their closely linked markers will be useful for fine mapping and marker-assisted selection (MAS) in breeding for durable resistance to multiple rust diseases.
| S-EPMC9274257 | biostudies-literature
Project description:Characterization of the genetic structure and the physiological races of Puccinia triticina is a growing necessity to apply host genetic resistance against wheat leaf rust as a successful control strategy. Herein, we collected and identified about 130 isolates of P. triticina from 16 Egyptian commercial wheat cultivars grown at different locations, over two seasons (2019/2020 and 2020/2021). The 130 isolates of P. triticina were segregated into 17 different physiological races. TTTST and TTTKS were the most common virulent races, whereas TTTST and MTTGT were the most frequent races. The races were classified into three groups, based on their distinct DNA band sizes (150 bp, 200 bp, and 300 bp) after RAPD analysis. The new wheat cultivars (Sakha-94, Sakha-95, and Shandweel-1) infected with the most virulent race (TTTST), Gemmeiza-12, and Misr-3 were resistant to all physiological races. The resistance of these cultivars was mostly due to the presence of Lr19- and Lr28-resistant genes. Our results serve as a warning about emerging aggressive races capable of supplanting resistance to leaf rust, and help in the understanding of the pathotype-cultivar-location association and its role in the susceptibility/resistance of new wheat cultivars to P. triticina.
| S-EPMC8471702 | biostudies-literature
Project description:Leaf rust caused by Puccinia triticina Erikss. (Pt) and stem rust caused by Puccinia graminis f. sp. tritici Erikss. & E. Henn (Pgt) are serious constraints to production of durum wheat (Triticum turgidum L). The objective of this study was to identify leaf rust resistance (Lr) and stem rust resistance (Sr) genes/QTL in Portuguese durum landrace PI 192051. Four Pt-isolates, representing three virulence phenotypes (BBBQJ, BBBSJ & EEEEE) and six Pgt-races TTKSK, JRCQC, TKTTF, QFCFC, TPMKC and TMLKC were used to evaluate 180 recombinant inbred lines (RILs) derived from the cross Rusty (rust susceptible) × PI 192051-1 (rust resistant) at the seedling stage. The RILs were also phenotyped at the adult-plant stage in a stem rust nursery in Ethiopia in 2017. The RILs were genotyped using the Illumina iSelect 9K wheat SNP array. PI 192051-1 carries a previously unidentified major Sr gene designated as QSr.ace-7A on chromosome arm 7AS and Lr gene Lr.ace-4A in the pericentromeric region of chromosome 4A. In addition, three minor Sr QTL QSr.ace-1A, QSr.ace-2B and QSr.ace-4A were mapped in PI 192051-1 on chromosomes 1AL, 2BL, and 4A, respectively Lr.ace-4A could be co-located or tightly linked to QSr.ace-4A Markers linked to the identified QTL/genes can be used for marker assisted selection. These findings enrich the genetic basis of rust resistance in both durum and common wheat.
| S-EPMC6686931 | biostudies-literature
Project description:Leaf rust is one of the most significant diseases of wheat worldwide. In Argentina, it is one of the main reasons for variety replacement that becomes susceptible after large-scale use. Some varieties showed durable resistance to this disease, including Buck Manantial and Sinvalocho MA. RILs (Recombinant Inbred Lines) were developed for each of these varieties and used in genetics studies to identify components of resistance, both in greenhouse inoculations using leaf rust races, and in field evaluations under natural population infections. In Buck Manantial, the APR gene LrBMP1 was associated with resistance in field tests. In crosses involving Sinvalocho MA, four genes were previously identified and associated with resistance in field testing: APR (Adult Plant Resistance) gene LrSV1, the APR genetic system LrSV2 + LrcSV2 and the ASR (All Stage Resistance) gene LrG6. Using backcrosses, LrBMP1 was introgressed in four commercial susceptible varieties and LrSV1, LrSV2 + LrcSV2 and LrG6 were simultaneously introgressed in three susceptible commercial varieties. The use of molecular markers for recurrent parent background selection allowed us to select resistant lines with more than 80% similarity to commercial varieties. Additionally, progress towards positional cloning of the genetic system LrSV2 + LrcSV2 for leaf rust APR is reported.
| S-EPMC8615195 | biostudies-literature
Project description:The wheat gene Lr1 imparts resistance to certain races of the leaf rust pathogen Puccinia triticina. However, the biological basis underlying the complex resistance mechanisms remains largely unknown. Gene expression profiling analyses using the Affymetrix GeneChip® Wheat Genome Array were performed with six independent Lr1 transgenic lines sampled before inoculation (0h) and at 6 and 24 h after inoculation with the avirulent P. triticina race CCDS. For the 6 and 24 h time points, 3 384 probe sets corresponding to 2 978 transcripts were differentially expressed as compared to the plants before inoculation. Genes involved in defence signalling were triggered as early as 6 h post inoculation (HPI) and included COI1, the primary component of jasmonic acid signalling. By 24 HPI, a shift in plant cellular metabolism, namely carbon conservation, was notable. The enzymes of glycolysis and gluconeogenesis were down-regulated, however, enzymes linked to alternative carbon sequestration processes such as the glyoxylate cycle were up-regulated. Also at 24 HPI, various secondary signalling molecules belonging to the various hormone signalling pathways were triggered. These microarray data suggest that the Lr1 mediated leaf rust resistance is achieved by early onset of defence signalling followed by co-ordinated interplay of metabolism alteration and elicitation of defence responses. We used microarrays to detail the early gene expression events underlying Lr1-mediated resistance to Puccinia triticina pathogen in wheat.
2012-09-14 | GSE32151 | GEO