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1.
Ann Hepatobiliary Pancreat Surg ; 27(3): 277-286, 2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-37547937

RESUMO

Backgrounds/Aims: To study histopathological changes in gall bladder mucosa in cholelithiasis patients, and analyse their relation to the number and size of gallstones. These findings were evaluated in the context of age distribution of the study population. Methods: One hundred cases of cholecystectomy were part of the study, which was conducted in collaboration with the pathology department. The time period of the study was January 2020 to June 2021. Results: Maximum cases had multiple stones (69.0%), while one third cases (31.0%) had solitary stones. While initial univariate analysis showed age (odds ratio [OR], 6.882; p = 0.043), gallstone number (OR, 9.1; p = 0.050), gallstone size (OR, 17.111; p = 0.013), and duration of symptom (OR, 34.125; p = 0.001) to be significant risk factors associated with gallbladder carcinoma, multivariate analysis found none of these variables to be significant. However, conditional multivariate analysis for the duration of symptom (p = 0.008; OR, 21.118) yielded significant p- value. With histopathological diagnoses, 5% of cases had gallbladder cancer. Conclusions: This study shed light on the rising incidence of cholelithiasis in the young population and the high rate of gallbladder carcinoma in Punjab, India. Although gall stone characteristics (size, number) and patient age appeared to be significant risk factors when their individual relation with gallbladder carcinoma was studied, multivariate analysis, could not prove that. Conditional multivariate analysis showed the duration of symptom to be the only significant risk factor associated with gallbladder carcinoma. Further research with larger sample size is needed to study the rising incidence of gallbladder carcinoma, and the risk factors associated with it.

2.
Plants (Basel) ; 12(8)2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-37111824

RESUMO

The Ug99-effective stem rust resistance gene Sr48 was mapped to chromosome 2A based on its repulsion linkage with Yr1 in an Arina/Forno recombinant inbred line (RIL) population. Attempts to identify markers closely linked to Sr48 using available genomic resources were futile. This study used an Arina/Cezanne F5:7 RIL population to identify markers closely linked with Sr48. Using the Arina/Cezanne DArTseq map, Sr48 was mapped on the short arm of chromosome 2D and it co-segregated with 12 markers. These DArTseq marker sequences were used for BlastN search to identify corresponding wheat chromosome survey sequence (CSS) contigs, and PCR-based markers were developed. Two simple sequence repeat (SSR) markers, sun590 and sun592, and two Kompetitive Allele-Specific PCR (KASP) markers were derived from the contig 2DS_5324961 that mapped distal to Sr48. Molecular cytogenetic analysis using sequential fluorescent in situ hybridization (FISH) and genomic in situ hybridization (GISH) identified a terminal translocation of chromosome 2A in chromosome 2DL of Forno. This translocation would have led to the formation of a quadrivalent involving chromosomes 2A and 2D in the Arina/Forno population, which would have exhibited pseudo-linkage between Sr48 and Yr1 in chromosome 2AL. Polymorphism of the closet marker sunKASP_239 among a set of 178 wheat genotypes suggested that this marker can be used for marker-assisted selection of Sr48.

4.
PLoS One ; 17(10): e0273993, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36201474

RESUMO

Stem rust caused by the fungus Puccinia graminis f.sp. tritici Eriks. & E. Henn. (Pgt) threatens the global production of both durum wheat (Triticum turgidum L. ssp. durum (Desf.) Husnot) and common wheat (Triticum aestivum L.). The objective of this study was to evaluate a durum wheat recombinant inbred line (RIL) population from a cross between a susceptible parent 'DAKIYE' and a resistant parent 'Reichenbachii' developed by the International Center for the Improvement of Maize and Wheat (CIMMYT) 1) for seedling response to races JRCQC and TTRTF and 2) for field response to a bulk of the current Pgt races prevalent in Ethiopia and Kenya and 3) to map loci associated with seedling and field resistances in this population. A total of 224 RILs along with their parents were evaluated at the seedling stage in the Ethiopian Institute for Agricultural Research greenhouse at Debre Zeit, Ethiopia and in the EIAR and KALRO fields in Ethiopia and Kenya, for two seasons from 2019 to 2020. The lines were genotyped using the genotyping-by-sequencing approach. A total of 843 single nucleotide polymorphism markers for 175 lines were used for quantitative trait locus (QTL) analyses. Composite interval mapping (CIM) identified three QTL on chromosomes 3B, 4B and 7B contributed by the resistant parent. The QTL on chromosome 3B was identified at all growth stages and it explained 11.8%, 6.5%, 6.4% and 15.3% of the phenotypic variation for responses to races JRCQC, TTRTF and in the field trials ETMS19 and KNMS19, respectively. The power to identify additional QTL in this population was limited by the number of high-quality markers, since several markers with segregation distortion were eliminated. A cytological study is needed to understand the presence of chromosomal rearrangements. Future evaluations of additional durum lines and RIL families identification of durable adult plant resistance sources is crucial for breeding stem rust resistance in durum wheat in the future.


Assuntos
Basidiomycota , Triticum , Basidiomycota/genética , Cromossomos de Plantas/genética , Resistência à Doença/genética , Humanos , Melhoramento Vegetal , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Locos de Características Quantitativas , Plântula/genética , Triticum/genética , Triticum/microbiologia
5.
Front Plant Sci ; 13: 880138, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36061764

RESUMO

Developing wheat varieties with durable resistance is a core objective of the International Maize and Wheat Improvement Center (CIMMYT) and many other breeding programs worldwide. The CIMMYT advanced wheat line "Mucuy" displayed high levels of resistance to stripe rust (YR) and leaf rust (LR) in field evaluations in Mexico and several other countries. To determine the genetic basis of YR and LR resistance, 138 F5 recombinant inbred lines (RILs) derived from the cross of Apav#1× Mucuy were phenotyped for YR responses from 2015 to 2020 at field sites in India, Kenya, and Mexico, and LR in Mexico. Seedling phenotyping for YR and LR responses was conducted in the greenhouse in Mexico using the same predominant races as in field trials. Using 12,681 polymorphic molecular markers from the DArT, SNP, and SSR genotyping platforms, we constructed genetic linkage maps and QTL analyses that detected seven YR and four LR resistance loci. Among these, a co-located YR/LR resistance loci was identified as Yr29/Lr46, and a seedling stripe rust resistance gene YrMu was mapped on the 2AS/2NS translocation. This fragment also conferred moderate adult plant resistance (APR) under all Mexican field environments and in one season in Kenya. Field trial phenotyping with Lr37-virulent Puccinia triticina races indicated the presence of an APR QTL accounting for 18.3-25.5% of the LR severity variation, in addition to a novel YR resistance QTL, QYr.cim-3DS, derived from Mucuy. We developed breeder-friendly KASP and indel molecular markers respectively for Yr29/Lr46 and YrMu. The current study validated the presence of known genes and identified new resistance loci, a QTL combination effect, and flanking markers to facilitate accelerated breeding for genetically complex, durable rust resistance.

6.
Theor Appl Genet ; 135(5): 1541-1550, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35199199

RESUMO

KEY MESSAGE: Adult plant stem rust resistance locus, QSrGH.cs-2AL, was identified in durum wheat Glossy Huguenot and mendelised as Sr63. Markers closely linked with Sr63 were developed. 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 90 K 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.


Assuntos
Basidiomycota , Triticum , Austrália , Basidiomycota/fisiologia , Mapeamento Cromossômico , Resistência à Doença/genética , Doenças das Plantas/genética , Caules de Planta/genética , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Triticum/genética
7.
Sci Rep ; 11(1): 21415, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34725387

RESUMO

Bread wheat (Triticum aestivum L.) cultivars adapted to specific environments and resistant to prevalent pathogens are preferred for obtaining high yield. This study aimed to identify wheat genotypes with superior grain yield (GY) and yield associated traits from 168 genotypes of International Maize and Wheat Improvement Center's 13th Stem Rust Resistance Screening Nursery evaluated over two seasons during 2019 and 2020 under high disease pressure of both stem rust (SR) and yellow rust (YR) in a 21 × 8 α-lattice design with 3 replications in Kenya. Effects due to seasons were significant for YRAud, SRAud, 1000-kernel weight (TKW), days to heading (DH), plant height (PH) and number of spikelets spike-1 (SS), while genotypes and genotypes × season interaction effects were significant for all traits except number of kernels spike-1. Respectively, heritability values of 0.95, 0.93, 0.87, 0.86, 0.77 and 0.75 were observed for area under disease progress curve for SR (SRAud), YR (YRAud), TKW, DH, biomass (BM) and GY. Path analysis showed positive direct effects on GY via PH, SS, BM, and TKW. Biplot analysis identified 16 genotypes with superior desirable traits GY, BM and harvest index. The SR contributed the highest reduction in GY and TKW while YR contributed the most reduction in BM. These identified genotypes with superior GY combined with adequate resistance to both SR and YR are potentially valuable resources for improvement of locally adapted wheat cultivars.


Assuntos
Grão Comestível/genética , Doenças das Plantas/genética , Triticum/genética , Alelos , Animais , Afídeos , Basidiomycota/genética , Biomassa , Pão , Clima , Estudo de Associação Genômica Ampla , Genótipo , Quênia , Fenótipo , Locos de Características Quantitativas , Análise de Regressão , Estações do Ano , Temperatura , Zea mays
8.
Clin Case Rep ; 9(7): e04576, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34322272

RESUMO

A patient presenting with worsening dyspnea and left-sided chest pain underwent heart catheterization, found to have a rare connection between the right and left coronary arteries draining into the left ventricle, consistent with dual coronary-cameral fistula.

9.
Plant Dis ; 105(12): 3998-4005, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34232053

RESUMO

Wheat stem rust caused by Puccinia graminis f. sp. tritici is a widespread and recurring threat to wheat production. Emerging P. graminis f. sp. tritici variants are rapidly overcoming major gene resistance deployed in wheat cultivars and new sources of race-nonspecific resistance are urgently needed. The National Small Grains Collection (NSGC) contains thousands of wheat landrace accessions that may harbor unique and broadly effective sources of resistance to emerging P. graminis f. sp. tritici variants. All NSGC available facultative and winter-habit bread wheat landraces were tested in a field nursery in St. Paul, Minnesota, against a bulk collection of six common U.S. P. graminis f. sp. tritici races. Infection response and severity data were collected on 9,192 landrace accessions at the soft-dough stage and resistant accessions were derived from single spikes. Derived accessions were tested in St. Paul a second time to confirm resistance and in a field nursery in Njoro, Kenya against emerging races of P. graminis f. sp. tritici with virulence to many known resistance genes including Sr24, Sr31, Sr38, and SrTmp. Accessions resistant in the St. Paul field were also tested at the seedling stage with up to 13 P. graminis f. sp. tritici races, including TTKSK and TKTTF, and with 19 molecular markers linked with known stem rust resistance genes or genes associated with modern breeding practices. Forty-five accessions were resistant in both U.S. and Kenya field nurseries and lacked alleles linked with known stem rust resistance genes. Accessions with either moderate or strong resistance in the U.S. and Kenya field nurseries and with novel seedling resistance will be prioritized for further study.


Assuntos
Resistência à Doença , Doenças das Plantas , Puccinia/patogenicidade , Triticum/genética , Resistência à Doença/genética , Melhoramento Vegetal , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Triticum/microbiologia
10.
J Invasive Cardiol ; 33(6): E489, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34089313

RESUMO

A 79-year-old woman presented with new-onset heart failure. She had pleural effusion, pericardial effusion, and an ejection fraction of 35% on echocardiogram. Her coronary angiogram revealed mild coronary artery disease (CAD). However, initially unexplained extravasation of the contrast was also seen in the cranial view during angiogram. The decision was made to medically manage CAD, but she remained tachycardic, with borderline low blood pressure. After a series of complications and tests, clearance of contrast from the stomach was confirmed. This represents an unusual case in which fluoroscopy revealed active gastric bleeding with contrast extravasation during coronary angiography.


Assuntos
Doença da Artéria Coronariana , Derrame Pericárdico , Idoso , Angiografia Coronária/efeitos adversos , Ecocardiografia , Feminino , Humanos , Estômago
11.
PLoS One ; 16(1): e0246015, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33513167

RESUMO

Deploying under-utilized landraces in wheat breeding has been advocated to accelerate genetic gains in current era of genomics assisted breeding. Mexican bread wheat landraces (Creole wheats) represent an important resource for the discovery of novel alleles including disease resistance. A core set of 1,098 Mexican landraces was subjected to multi-location testing for rust diseases in India, Mexico and Kenya. The landrace core set showed a continuous variation for yellow (YR) and stem rust (SR) disease severity. Principal component analysis differentiated Mexican landraces into three groups based on their respective collection sites. Linkage disequilibrium (LD) decay varied from 10 to 32 Mb across chromosomes with an averge of 23Mb across whole genome. Genome-wide association analysis revealed marker-trait associations for YR resistance in India and Mexico as well as for SR resistance in Kenya. In addition, significant additive-additive interaction effects were observed for both YR and SR resistance including genomic regions on chromosomes 1BL and 3BS, which co-locate with pleiotropic genes Yr29/Lr46/Sr58/Pm39/Ltn2 and Sr2/Yr30/Lr27, respectively. Study reports novel genomic associations for YR (chromosomes 1AL, 2BS, and 3BL) and SR (chromosomes 2AL, 4DS, and 5DS). The novel findings in Creole wheat landraces can be efficiently utilized for the wheat genetic improvement.


Assuntos
Basidiomycota , Resistência à Doença/genética , Doenças das Plantas/genética , Triticum/genética , Mapeamento Cromossômico , Genoma de Planta , Estudo de Associação Genômica Ampla , Desequilíbrio de Ligação , Fenótipo , Melhoramento Vegetal , Doenças das Plantas/microbiologia , Locos de Características Quantitativas
12.
Sci Rep ; 10(1): 10908, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32616836

RESUMO

Stripe or yellow rust (YR) caused by Puccinia striiformis Westend. f. sp. tritici Erikss. is a persistent biotic-stress threatening global wheat production. To broaden our understanding of the shared genetic basis of YR resistance across multi-site and multi-year evaluations, we performed a large genome-wide association study using 43,706 YR observations on 23,346 wheat lines from the International Maize and Wheat Improvement Center evaluated between 2013 and 2019 at sites in India, Kenya and Mexico, against predominant races prevalent in the countries. We identified 114 repeatable markers tagging 20 quantitative trait loci (QTL) associated with YR on ten chromosomes including 1D, 2A, 2B, 2D, 3A, 4A, 4D, 5A, 5B and 6B, among which four QTL, QYr.cim-2DL.2, QYr.cim-2AS.1, QYr.cim-2BS.2 and QYr.cim-2BS.3 were significant in more than ten datasets. Furthermore, we report YR-associated allelic fingerprints for the largest panel of wheat breeding lines (52,067 lines) till date, creating substantial opportunities for YR favorable allele enrichment using molecular markers. Overall, the markers and fingerprints reported in this study provide excellent insights into the genetic architecture of YR resistance in different geographical regions, time-periods and wheat germplasm and are a huge resource to the global wheat breeding community for accelerating YR resistance breeding efforts.


Assuntos
Genoma de Planta , Doenças das Plantas/genética , Puccinia , Triticum/genética , Alelos , Cromossomos de Plantas/genética , Resistência à Doença/genética , Marcadores Genéticos , Genoma de Planta/genética , Estudo de Associação Genômica Ampla , Quênia , Desequilíbrio de Ligação , México , Melhoramento Vegetal , Doenças das Plantas/microbiologia , Análise de Componente Principal , Locos de Características Quantitativas , Plântula/microbiologia , Triticum/microbiologia
13.
JAMA Netw Open ; 3(4): e202175, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32250434

RESUMO

Importance: Several studies have examined the role of warfarin in preventing strokes in patients with atrial fibrillation and end-stage renal disease; however, the results remain inconclusive. Objective: To assess recently published studies to examine the outcomes of the use of warfarin among patients with atrial fibrillation and end-stage renal disease. Data Sources: A literature search was performed using the terms warfarin and atrial fibrillation and end-stage renal disease and warfarin and atrial fibrillation and dialysis in the MEDLINE, Embase, and Google Scholar databases from January 1, 2008, to February 28, 2019. Study Selection: The studies included were those with patients with end-stage renal disease and atrial fibrillation who were receiving warfarin and with hazard ratios (HRs) of at least 1 primary outcome. The studies excluded were those with a lack of information on outcomes and unreliable 95% CIs of the results. Data Extraction and Synthesis: The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines were followed in selecting studies. Collected data were also scrutinized for reliable 95% CIs. Finally, studies were examined for perceived biases, their limitations, and the definitions of the outcomes. Main Outcomes and Measures: The HRs and 95% CIs were calculated for the incidence of ischemic stroke, hemorrhagic stroke, major bleeding, and mortality among patients receiving anticoagulants and those not receiving anticoagulants. Results: Study selection yielded 15 studies with a total of 47 480 patients with atrial fibrillation and end-stage renal disease. Of these patients, 10 445 (22.0%) were taking warfarin. With a mean (SD) follow-up period of 2.6 (1.4) years, warfarin use was associated with no significant change for the risk of ischemic stroke (HR, 0.96; 95% CI, 0.82-1.13), with a significantly higher risk of hemorrhagic stroke (HR, 1.49; 95% CI, 1.03-1.94), with no significant difference in the risk of major bleeding (HR, 1.20; 95% CI, 0.99-1.47), and with no change in overall mortality (HR, 0.95; 95% CI, 0.83-1.09). Conclusions and Relevance: In the studies reviewed, warfarin use appears to have been associated with no change in the incidence of ischemic stroke in patients with atrial fibrillation and end-stage renal disease. However, from the studies reviewed, it does appear to be associated with a significantly higher risk of hemorrhagic stroke, with no significant difference in the risk of major bleeding, and with no change in mortality.


Assuntos
Anticoagulantes/uso terapêutico , Fibrilação Atrial , Falência Renal Crônica , Varfarina/uso terapêutico , Idoso , Fibrilação Atrial/complicações , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/epidemiologia , Fibrilação Atrial/mortalidade , Feminino , Humanos , Falência Renal Crônica/complicações , Falência Renal Crônica/epidemiologia , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/prevenção & controle , Resultado do Tratamento
14.
Plant Dis ; 104(5): 1455-1464, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32196419

RESUMO

Leaf (brown) rust (LR) and stripe (yellow) rust (YR), caused by Puccinia triticina and P. striiformis f. sp. tritici, respectively, significantly reduce wheat production worldwide. Disease-resistant wheat varieties offer farmers one of the most effective ways to manage these diseases. The common wheat (Triticum aestivum L.) Arableu#1, developed by the International Maize and Wheat Improvement Center and released as Deka in Ethiopia, shows susceptibility to both LR and YR at the seedling stage but a high level of adult plant resistance (APR) to the diseases in the field. We used 142 F5 recombinant inbred lines (RILs) derived from Apav#1 × Arableu#1 to identify quantitative trait loci (QTLs) for APR to LR and YR. A total of 4,298 genotyping-by-sequencing markers were used to construct a genetic linkage map. The study identified four LR resistance QTLs and six YR resistance QTLs in the population. Among these, QLr.cim-1BL.1/QYr.cim-1BL.1 was located in the same location as Lr46/Yr29, a known pleiotropic resistance gene. QLr.cim-1BL.2 and QYr.cim-1BL.2 were also located on wheat chromosome 1BL at 37 cM from Lr46/Yr29 and may represent a new segment for pleiotropic resistance to both rusts. QLr.cim-7BL is likely Lr68 given its association with the tightly linked molecular marker cs7BLNLRR. In addition, QLr.cim-3DS, QYr.cim-2AL, QYr.cim-4BL, QYr.cim-5AL, and QYr.cim-7DS are probably new resistance loci based on comparisons with published QTLs for resistance to LR and YR. Our results showed the diversity of minor resistance QTLs in Arableu#1 and their role in conferring near-immune levels of APR to both LR and YR, when combined with the pleiotropic APR gene Lr46/Yr29.


Assuntos
Resistência à Doença , Triticum , Mapeamento Cromossômico , Etiópia , Humanos , Doenças das Plantas
15.
Front Plant Sci ; 11: 609659, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33510752

RESUMO

Stem rust caused by Puccinia graminis f. sp. tritici (Pgt) remains a constraint to wheat production in East Africa. In this study, we characterized the genetics of stem rust resistance, identified QTLs, and described markers associated with stem rust resistance in the spring wheat line CI 14275. The 113 recombinant inbred lines, together with their parents, were evaluated at the seedling stage against Pgt races TTKSK, TRTTF, TPMKC, TTTTF, and RTQQC. Screening for resistance to Pgt races in the field was undertaken in Kenya, Ethiopia, and the United States in 2016, 2017, and 2018. One gene conferred seedling resistance to race TTTTF, likely Sr7a. Three QTL were identified that conferred field resistance. QTL QSr.cdl-2BS.2, that conferred resistance in Kenya and Ethiopia, was validated, and the marker Excalibur_c7963_1722 was shown to have potential to select for this QTL in marker-assisted selection. The QTL QSr.cdl-3B.2 is likely Sr12, and QSr.cdl-6A appears to be a new QTL. This is the first study to both detect and validate an adult plant stem rust resistance QTL on chromosome arm 2BS. The combination of field QTL QSr.cdl-2BS.2, QSr.cdl-3B.2, and QSr.cdl-6A has the potential to be used in wheat breeding to improve stem rust resistance of wheat varieties.

16.
Front Plant Sci ; 11: 598509, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33391309

RESUMO

Stem rust of wheat caused by Puccinia graminis Pers. f.sp. trtici Eriks and E. Henn., is the most damaging fungal disease of both common (Triticum aestivum L.) and durum (Triticum turgidum L., ssp. Durum) wheat. Continuously emerging races virulent to many of the commercially deployed qualitative resistance genes have caused remarkable loss worldwide and threaten global wheat production. The objectives of this study were to evaluate the response of a panel of 283 durum wheat lines assembled by the International Maize and Wheat Improvement Center (CIMMYT) to multiple races of stem rust in East Africa at the adult plant stage and map loci associated with field resistance. The lines were evaluated in Debre Zeit, Ethiopia and Njoro, Kenya from 2018 to 2019 in five environments (year × season). The panel was genotyped using genotyping-by-sequencing. After filtering, 26,439 Single Nucleotide Polymorphism (SNP) markers and 280 lines and three checks were retained for analysis. Population structure was assessed using principal component analysis. Genome-wide association analysis (GWAS) was conducted using Genomic Association and Prediction Integrated Tool (GAPIT). The broad-sense heritability of the phenotype data revealed that 64-83% of the variation in stem rust response explained by the genotypes and lines with multiple race resistance were identified. GWAS analysis detected a total of 160 significant marker trait associations representing 42 quantitative trait loci. Of those, 21 were potentially novel and 21 were mapped to the same regions as previously reported loci. Known stem rust resistance genes/alleles were postulated including Sr8a, Sr8155B1, SrWeb/Sr9h, Sr11, Sr12, Sr13/Sr13 alleles, Sr17, Sr28/Sr16, Sr22, and Sr49. Lines resistant to multiple races in East Africa can be utilized as parents in durum wheat breeding programs. Further studies are needed to determine if there are new alleles at the Sr13 locus and potential markers for the known Sr13 alleles.

17.
Phytopathology ; 110(4): 892-899, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31850832

RESUMO

The durum wheat lines Heller#1 and Dunkler from the International Maize and Wheat Improvement Center Global Wheat Program showed moderate and stable adult plant resistance to leaf rust under high disease pressure over field environments in northwestern Mexico. Leaf rust phenotyping was performed on two recombinant inbred line (RIL) populations derived from crosses of Heller#1 and Dunkler with the susceptible parent Atred#2, conducted under artificially induced Puccinia triticina epidemics in 2013, 2014, 2015, and 2016. The Atred#2 × Heller#1 and Atred#2 × Dunkler populations were genotyped by single nucleotide polymorphism (SNP) platforms and diversity arrays technology markers, respectively. Four leaf rust resistance quantitative trait loci were detected simultaneously in the two RIL populations: Lr46, QLr.cim-2BC, QLr.cim-5BL, and QLr.cim-6BL based on phenotypic data across all four crop seasons. They explained 11.7 to 46.8%, 7.2 to 26.1%, 8.4 to 24.1%, and 12.4 to 28.5%, respectively, of the phenotypic variation for leaf rust resistance in Atred#2 × Heller#1 and 16.3 to 56.6%, 6.7 to 15.7%, 4.1 to 10.1%, and 5.1 to 20.2% of the variation in the Atred#2 × Dunkler population. Only the resistance allele of QLr.cim-2BC was from the susceptible parent Atred#2, and resistance alleles at other loci came from the resistant parents Heller#1 and Dunkler. The SNP markers closely linked to Lr46 and QLr.cim-2BC were converted to kompetitive allele specific PCR markers for use in marker-assisted selection to improve leaf rust resistance through crosses with Heller#1 and Dunkler sources.


Assuntos
Basidiomycota , Triticum , Mapeamento Cromossômico , Resistência à Doença , Humanos , México , Doenças das Plantas
18.
Nat Genet ; 51(10): 1530-1539, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31548720

RESUMO

Bread wheat improvement using genomic tools is essential for accelerating trait genetic gains. Here we report the genomic predictabilities of 35 key traits and demonstrate the potential of genomic selection for wheat end-use quality. We also performed a large genome-wide association study that identified several significant marker-trait associations for 50 traits evaluated in South Asia, Africa and the Americas. Furthermore, we built a reference wheat genotype-phenotype map, explored allele frequency dynamics over time and fingerprinted 44,624 wheat lines for trait-associated markers, generating over 7.6 million data points, which together will provide a valuable resource to the wheat community for enhancing productivity and stress resilience.


Assuntos
Resistência à Doença/genética , Genômica/métodos , Locos de Características Quantitativas , Estresse Fisiológico/imunologia , Triticum/crescimento & desenvolvimento , Triticum/imunologia , Ascomicetos/fisiologia , Mapeamento Cromossômico , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Estudos de Associação Genética , Marcadores Genéticos , Genoma de Planta , Estudo de Associação Genômica Ampla , Melhoramento Vegetal , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Seleção Genética , Estresse Fisiológico/genética , Triticum/genética
19.
Phytopathology ; 109(1): 120-126, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30070970

RESUMO

Stripe rust is a major disease constraint of wheat production worldwide. Resistance to stripe rust was analyzed using 131 F6 recombinant inbred lines (RILs) derived from a cross between synthetic derived wheat line Soru#1 and wheat cultivar Naxos. The phenotype was evaluated in Mexico and Norway at both seedling and adult plant stages. Linkage groups were constructed based on 90K single-nucleotide polymorphism (SNP), sequence-tagged site, and simple sequence repeat markers. Two major resistance loci conferred by Soru#1 were detected and located on chromosomes 1BL and 4DS. The 1BL quantitative trait loci explained 15.8 to 40.2 and 51.1% of the phenotypic variation at adult plant and seedling stages, respectively. This locus was identified as Yr24/Yr26 based on the flanking markers and infection types. Locus 4DS was flanked by molecular markers D_GB5Y7FA02JMPQ0_238 and BS00108770_51. It explained 8.4 to 27.8 and 5.5% of stripe rust variation at the adult plant and seedling stages, respectively. The 4DS locus may correspond to known resistance gene Yr28 based on the resistance source. All RILs that combine Yr24/Yr26 and Yr28 showed significantly reduced stripe rust severity in all four environments compared with the lines with only one of the genes. SNP marker BS00108770_51 was converted into a breeder-friendly kompetitive allele-specific polymerase chain reaction marker that will be useful to accelerate Yr28 deployment in wheat breeding programs.


Assuntos
Basidiomycota , Resistência à Doença/genética , Doenças das Plantas/genética , Triticum/genética , Mapeamento Cromossômico , Genes de Plantas , Marcadores Genéticos , México , Noruega , Fenótipo , Doenças das Plantas/microbiologia , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Triticum/microbiologia
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