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Leaf rust, caused by Puccinia triticina, is an important fungal disease of wheat (Triticum aestivum L.) and causes significant yield losses worldwide. To determine quantitative trait loci (QTLs) responsible for leaf rust resistance, a... more
Leaf rust, caused by Puccinia triticina, is an important fungal disease of wheat (Triticum aestivum L.) and causes significant yield losses worldwide. To determine quantitative trait loci (QTLs) responsible for leaf rust resistance, a recombinant inbred line (RIL) population developed from a cross of Ning7840 × Clark was evaluated for leaf rust severity, and was genotyped for single nucleotide polymorphisms (SNPs) using 9K Illumina chips, and with simple sequence repeat (SSR) markers. Two major QTLs on chromosome arms 7DS and 3BS, and two minor QTLs on chromosomes 5AS and 6AS showed a significant effect on leaf rust severity. The 7DS QTL from Ning7840 and the 3BS QTL from Clark explained, respectively, about 35% and 18% of the phenotypic variation for leaf rust resistance. The QTL on 7DS was confirmed to be Lr34. The QTL on 3BS, QLr.hwwg-3B.1, was associated with adult plant resistance and was provisionally identified as Lr74. QLr.hwwg-5AS and QLr.hwwg-6AS from Ning7840 and Clark, r...
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Plant organs, such as seeds, are primary sources of food for both humans and animals. Seed size is one of the major agronomic traits that have been selected in crop plants during their domestication. Legume seeds are a major source of... more
Plant organs, such as seeds, are primary sources of food for both humans and animals. Seed size is one of the major agronomic traits that have been selected in crop plants during their domestication. Legume seeds are a major source of dietary proteins and oils. Here, we report a conserved role for the BIG SEEDS1 (BS1) gene in the control of seed size and weight in the model legume Medicago truncatula and the grain legume soybean (Glycine max). BS1 encodes a plant-specific transcription regulator and plays a key role in the control of the size of plant organs, including seeds, seed pods, and leaves, through a regulatory module that targets primary cell proliferation. Importantly, down-regulation of BS1 orthologs in soybean by an artificial microRNA significantly increased soybean seed size, weight, and amino acid content. Our results provide a strategy for the increase in yield and seed quality in legumes.
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Eight QTL for coleoptile length were identified in a genome-wide association study on a set of 893 wheat accessions, four of which are novel loci. Wheat cultivars with long coleoptiles are preferred in wheat-growing regions where deep... more
Eight QTL for coleoptile length were identified in a genome-wide association study on a set of 893 wheat accessions, four of which are novel loci. Wheat cultivars with long coleoptiles are preferred in wheat-growing regions where deep planting is practiced. However, the wide use of gibberellic acid (GA)-insensitive dwarfing genes, Rht-B1b and Rht-D1b, makes it challenging to breed dwarf wheat cultivars with long coleoptiles. To understand the genetic basis of coleoptile length, we performed a genome-wide association study on a set of 893 landraces and historical cultivars using 5011 single nucleotide polymorphism (SNP) markers. Structure analysis revealed four subgroups in the association panel. Association analysis results suggested that Rht-B1b and Rht-D1b genes significantly reduced coleoptile length, and eight additional quantitative trait loci (QTL) for coleoptile length were also identified. These QTL explained 1.45-3.18 and 1.36-3.11% of the phenotypic variation in 2015 and 2...
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Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe, is a devastating disease in wheat (Triticum aestivum L.). Use of host resistance is one of the most effective strategies to minimize the disease damage. Haiyanzhong (HYZ)... more
Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe, is a devastating disease in wheat (Triticum aestivum L.). Use of host resistance is one of the most effective strategies to minimize the disease damage. Haiyanzhong (HYZ) is a Chinese wheat landrace that shows a high level of resistance to FHB spread within a spike (type II resistance). To map the quantitative trait loci (QTLs) in HYZ and identify markers tightly linked to the QTLs for FHB resistance, a population of 172 recombinant inbred lines (RILs) from a cross between HYZ and Wheaton (FHB susceptible) was genotyped using simple sequence repeats (SSRs) and single-nucleotide polymorphisms (SNPs) derived from genotyping-by-sequencing (GBS), and evaluated for percentage of symptomatic spikelets (PSSs) per spike in three greenhouse experiments. Six QTLs for type II resistance were identified in HYZ, indicating that multiple minor QTLs together can provide a high level of FHB resistance in wheat. The QTL with the lar...
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Using bulk segregant analysis (BSA) coupling with RNA-seq and DNA markers identified a potentially novel nitrogen-dependent lesion mimic gene Ndhrl1 on 2BS in wheat. Lesion mimic (LM) refers to hypersensitive reaction-like (HRL) traits... more
Using bulk segregant analysis (BSA) coupling with RNA-seq and DNA markers identified a potentially novel nitrogen-dependent lesion mimic gene Ndhrl1 on 2BS in wheat. Lesion mimic (LM) refers to hypersensitive reaction-like (HRL) traits that appear on leaf tissue in the absence of plant pathogens. In a wheat line P7001, LM showed up on the leaves under the 0 g nitrogen (N) treatment, but disappeared when sufficient N was supplied, suggesting that LM is N-responsive and N dosage dependent. Using BSA strategy together with RNA-seq and DNA markers, we identified an N-dependent LM gene (Ndhrl1) and mapped it to the short arm of chromosome 2B using an F5 recombinant inbred population developed from the cross of P7001 × P216. The putative gene was delimited into an interval of 8.1 cM flanked by the CAPS/dCAPS markers 7hrC9 and 7hr2dc14, and co-segregated with the dCAPS marker 7hrdc2. This gene is most likely a novel gene for LM in wheat based on its chromosomal location. Further analysis o...
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Molecular markers associated with known quantitative trait loci (QTLs) for type 2 resistance to Fusarium head blight (FHB) in bi-parental mapping population usually have more than two alleles in breeding populations. Therefore,... more
Molecular markers associated with known quantitative trait loci (QTLs) for type 2 resistance to Fusarium head blight (FHB) in bi-parental mapping population usually have more than two alleles in breeding populations. Therefore, understanding the association of each allele with FHB response is particularly important to marker-assisted enhancement of FHB resistance. In this paper, we evaluated FHB severities of 192 wheat accessions including landraces and commercial varieties in three field growing seasons, and genotyped this panel with 364 genome-wide informative molecular markers. Among them, 11 markers showed reproducible marker-trait association (p < 0.05) in at least two experiments using a mixed model. More than two alleles were identified per significant marker locus. These alleles were classified into favorable, unfavorable and neutral alleles according to the normalized genotypic values. The distributions of effective alleles at these loci in each wheat accession were char...
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ABSTRACT The objectives of this study were to validate the major quantitative trait locus (QTL) for scab resistance on the short arm of chromosome 3B in bread wheat and to isolate near-isogenic lines for this QTL using marker-assisted... more
ABSTRACT The objectives of this study were to validate the major quantitative trait locus (QTL) for scab resistance on the short arm of chromosome 3B in bread wheat and to isolate near-isogenic lines for this QTL using marker-assisted selection (MAS). Two resistant by susceptible populations, both using &#39;Ning7840&#39; as the source of resistance, were developed to examine the effect of the 3BS QTL in different genetic backgrounds. Data for scab resistance and simple sequence repeat (SSR) markers linked to the resistance QTL were analyzed in the F2:3 lines of one population and in the F3:4 lines of the other. Markers linked to the major QTL on chromosome 3BS in the original mapping population (&#39;Ning7840&#39;/&#39;Clark&#39;) were closely associated with scab resistance in both validation populations. Marker-assisted selection for the QTL with the SSR markers combined with phenotypic selection was more effective than selection based solely on phenotypic evaluation in early generations. Marker-assisted selection of the major QTL during the seedling stage plus phenotypic selection after flowering effectively identified scab resistant lines in this experiment. Near-isogenic lines for this 3BS QTL were isolated from the F6 generation of the cross &#39;Ning7840&#39;/&#39;IL89-7978&#39; based on two flanking SSR markers, Xgwm389 and Xbarc147. Based on these results, MAS for the major scab resistance QTL can improve selection efficiency and may facilitate stacking of scab resistance genes from different sources.
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Wheat scab, caused by Fusarium graminearum, is a destructive disease of wheat. Uncertainty about the inheritance of cultivar resistance and lack of reliable screening techniques have impeded progress in breeding resistant cultivars. In... more
Wheat scab, caused by Fusarium graminearum, is a destructive disease of wheat. Uncertainty about the inheritance of cultivar resistance and lack of reliable screening techniques have impeded progress in breeding resistant cultivars. In this study, components and inheritance of cultivar resistance were characterized, and factors influencing resistance expression were investigated. Wheat cultivars significantly differ in degree of resistance to scab spread within a spike when tested with different isolates of the fungus in different experiments. When single spikelets were inoculated, spread of scab within a spike was less frequent, later and slower in resistant cultivars than in susceptible cultivars. Measurement of scab spread within a spike is a stable characteristic by which resistance of a cultivar may be assessed.^ Inheritance of cultivar resistance to spread of scab within a spike was investigated in F$\sb1,$ F$\sb2,$ and backcross populations of 11 wheat crosses and in F$\rm\sb5,\ F\sb6\ and\ F\sb7$ progenies of Ning 7840/Clark. One to 3 major genes, depending on the cultivars, with possibly modifying genes conditioned resistance to scab. Additive effects accounted for most of the genetic variation although dominance and epistasis were detected. With bulked segregant analysis, 10 out of 1120 random decamer primers showed polymorphisms between bulked DNAs from the most resistant and the most susceptible F$\sb6$ families of Ning 7840/Clark. Five polymorphic bands indicated a significant association with 2 resistance genes, either in repulsion or coupling.^ Scab incidence increased and incubation period decreased as moist periods increased from 0 to 3 nights after inoculation. Scab severity was not affected by moist period during incubation, but affected by temperatures (14, 23, or 30 C) after incubation. Scab spread within a spike was greatest at 23 C. Moisture had no effect on scab spread. Resistant cultivars had consistently low severity under all conditions studied. In addition, both scab incidence and severity significantly increased as inoculum concentration increased. Scab incidence was more affected by moist period after inoculation, inoculum concentration, and inoculation method (injecting spores versus spraying spores) compared to severity. Flowering was the most susceptible stage for infection. ^
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Segregation distortion is a widespread phenomenon in plant and animal genomes and significantly affects linkage map construction and identification of quantitative trait loci (QTLs). To study segregation distortion in wheat, a... more
Segregation distortion is a widespread phenomenon in plant and animal genomes and significantly affects linkage map construction and identification of quantitative trait loci (QTLs). To study segregation distortion in wheat, a high-density consensus map was constructed using single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers by merging two genetic maps developed from two recombinant-inbred line (RIL) populations, Ning7840 × Clark and Heyne × Lakin. Chromosome regions with obvious segregation distortion were identified in the map. A total of 3541 SNPs and 145 SSRs were mapped, and the map covered 3258.7 cM in genetic distance with an average interval of 0.88 cM. The number of markers that showed distorted segregation was 490 (18.5%) in the Ning7840 × Clark population and 225 (10.4%) in the Heyne × Lakin population. Most of the distorted markers (630) were mapped in the consensus map, which accounted for 17.1% of mapped markers. The majority of the distorted...
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Variation in Fusarium graminearum and Cultivar Resistance to Wheat Scab Gui-Hua Bai, former Graduate Research Assistant, and Gregory Shatter, Professor, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN... more
Variation in Fusarium graminearum and Cultivar Resistance to Wheat Scab Gui-Hua Bai, former Graduate Research Assistant, and Gregory Shatter, Professor, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907-1155 ABSTRACT Bai, GH.. and ...
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ABSTRACT Continuous improvement in grain yield is one of the major challenges for wheat (Triticum aestivum L.) breeding worldwide. This study characterized quantitative trait loci (QTL) underlying wheat grain yield and its components... more
ABSTRACT Continuous improvement in grain yield is one of the major challenges for wheat (Triticum aestivum L.) breeding worldwide. This study characterized quantitative trait loci (QTL) underlying wheat grain yield and its components using a high-density genetic linkage map developed from a recombinant inbred line (RIL) population derived from ‘Ning7840’ × ‘Clark’. The map consisted of 594 single nucleotide polymorphism and 404 simple sequence repeat markers covering a genetic distance of 4225.7 cM. The RIL population was evaluated for grain yield (GY), spike number per m2 (SNPM), kernel number per spike (KNPS), and thousand-kernel weight (TKW) in three Oklahoma locations from 2001 to 2003. A total of 29 additive QTL (eight for GY, two for SNPM, five for KNPS, and 14 for TKW) were mapped on 13 chromosomes. Eight pairs of epistatic QTL were detected for different yield components: four for GY, two for KNPS, and two for TKW. Four additive QTL, including two for GY and two for KNPS, showed additive × environment interactions. QTL that were repeatable in multiple environments were identified for all traits except SNPM. Positive alleles were dispersed between the two parents for all traits, with ‘Clark’ contributing slightly more. Seven pleiotropic loci were co-localized for at least two traits. Interestingly, all co-localized loci overlapped for TKW, and four of them overlapped for GY. Thus, selecting QTL for TKW may simultaneously select for or against yield or other yield components in breeding.
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Preharvest sprouting (PHS) is one of the major constraints of wheat production in areas where prolonged rainfall occurs during harvest. TaPHS1 is a gene that regulates PHS resistance on chromosome 3A of wheat, and two causal mutations in... more
Preharvest sprouting (PHS) is one of the major constraints of wheat production in areas where prolonged rainfall occurs during harvest. TaPHS1 is a gene that regulates PHS resistance on chromosome 3A of wheat, and two causal mutations in the positions +646 and +666 of the TaPHS1 coding region result in wheat PHS susceptibility. Three competitive allele-specific PCR (KASP) markers were developed based on the two mutations in the coding region and one in the promoter region and validated in 82 wheat cultivars with known genotypes. These markers can be used to transfer TaPHS1 in breeding through marker-assisted selection. Screening of 327 accessions of wheat A genome progenitors using the three KASP markers identified different haplotypes in both diploid and tetraploid wheats. Only one Triticum monococcum accession, however, carries both causal mutations in the TaPHS1 coding region and shows PHS susceptibility. Five of 249 common wheat landraces collected from the Fertile Crescent and ...
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Using a GBS-SNP map, a QTL for pre-harvest sprouting resistance on 4AL of Totoumai A was delimited to 2.9-cM interval, and SNP closely linked to several other QTL were identified. Pre-harvest sprouting (PHS) of wheat is a major constraint... more
Using a GBS-SNP map, a QTL for pre-harvest sprouting resistance on 4AL of Totoumai A was delimited to 2.9-cM interval, and SNP closely linked to several other QTL were identified. Pre-harvest sprouting (PHS) of wheat is a major constraint to wheat production in many wheat-growing areas worldwide, because it reduces both wheat grain yield and the end-use quality. To identify markers tightly linked to the quantitative trait loci (QTL) for PHS resistance and seed dormancy (SD), we evaluated 155 recombinant inbred lines (RIL) derived from a cross between a PHS-resistant parent 'Tutoumai A' and a PHS-susceptible parent 'Siyang 936' for single-nucleotide polymorphisms (SNP) using genotyping-by-sequencing (GBS), and for PHS resistance and SD using both field and greenhouse grown plants. Two SNP, GBS109947 and GBS212432, were mapped to a major QTL region for PHS resistance and SD on chromosome 4AL, and delimited the QTL to a 2.9-cM interval. Two and nine additional SNP were ...
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Transient heat stress compromises resistance of host plants to Hessian fly, Mayetiola destructor (Say), and other biotic stresses. However, the mechanism for the loss of plant resistance under heat stress remains to be determined. In this... more
Transient heat stress compromises resistance of host plants to Hessian fly, Mayetiola destructor (Say), and other biotic stresses. However, the mechanism for the loss of plant resistance under heat stress remains to be determined. In this study, we determined polar lipid profiles in control and Hessian fly-infested resistant and susceptible wheat seedlings with and without heat stress using an automated electrospray ionization tandem mass spectrometry analysis. Heat stress, alone or in combination with Hessian fly infestation, caused significant reduction in the abundance of total detected polar lipids and double bond index. Changes in lipid profiles in &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;Molly&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; were similar to those in &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;Newton&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; under heat stress. However, changes in lipid profiles in Molly were significantly different from those in Newton following Hessian fly infestation. The combination of heat stress and Hessian fly infestation resulted in unique lipid profiles in comparison with those in plants either treated with heat stress or infested with Hessian fly alone. In addition, a greater impact on lipid metabolism was observed in heat-stressed plants infested with Hessian fly than that in plants treated with either heat stress or Hessian fly alone. Our results suggest that changes in lipid metabolism caused by heat stress may be part of the metabolic pathways through which heat stress suppresses resistance of wheat plants to Hessian fly infestation.
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ABSTRACT Next-generation sequencing (NGS) technologies open up a wealth of opportunities for plant breeding and genomic research and change the paradigms of DNA marker detection, genotyping, and gene discovery. Abundant genomic resources... more
ABSTRACT Next-generation sequencing (NGS) technologies open up a wealth of opportunities for plant breeding and genomic research and change the paradigms of DNA marker detection, genotyping, and gene discovery. Abundant genomic resources have been generated using a whole-genome resequencing (WGR) strategy and utilized in genome-wide association, genome diversity, and evolution studies in many crops with a reference genome such as rice and maize. The WGR-based quantitative trait loci mapping approach developed in soybean combines single nucleotide polymorphism (SNP) discovery, validation and genotyping and has the potential to identify candidate genes and causal SNPs without a time-consuming fine-mapping process. Given that this approach solves issues caused by genome duplications and repetitive sequences, it can be widely utilized in crops with a reference genome. The combination of WGR with bulked segregant analysis provides a rapid way to identify genes or causal mutations. Currently, DNA sequencing technologies are being improved rapidly. Third-generation sequencing platforms can overcome some inherent disadvantages of NGS and are expected to promote the application of WGR-based approaches and revolutionize plant breeding, genomic and genetic research.
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Chinese Spring Sumai 3 chromosome 7A disomic substitution line (CS-SM3-7ADS) is highly resistant to Fusarium head blight (FHB), and an F(7) population of recombinant inbred lines derived from the cross CS-SM3-7ADS x Annong 8455 was... more
Chinese Spring Sumai 3 chromosome 7A disomic substitution line (CS-SM3-7ADS) is highly resistant to Fusarium head blight (FHB), and an F(7) population of recombinant inbred lines derived from the cross CS-SM3-7ADS x Annong 8455 was evaluated for resistance to FHB to investigate main effects, epistasis, and environmental interactions of quantitative trait loci (QTLs) for FHB resistance. A molecular linkage map consists of 501 simple sequence repeat and amplified fragment length polymorphism markers. A total of 10 QTLs were identified with significant main effects on the FHB resistance using MapQTL and QTLMapper software. Among them, CS-SM3-7ADS carries FHB-resistance alleles at five QTLs on chromosomes 2D, 3B, 4D, and 6A. One QTL on 3BS had the largest effect and explained 30.2% of the phenotypic variance. Susceptible QTLs were detected on chromosomes 1A, 1D, 4A, and 4B. A QTL for enhanced FHB resistance was not detected on chromosome 7A of CS-SM3-7ADS; therefore, the increased FHB r...
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Fusarium graminearum is a major pathogen that causes fusarium head blight (FHB) in wheat and produces deoxynivalenol (DON) in infected grain. In previous studies, the trichodiene synthase gene (Tri5) in the fungal strain GZ3639 was... more
Fusarium graminearum is a major pathogen that causes fusarium head blight (FHB) in wheat and produces deoxynivalenol (DON) in infected grain. In previous studies, the trichodiene synthase gene (Tri5) in the fungal strain GZ3639 was disrupted to produce the DON-nonproducing strain GZT40. In this report, the virulence of strains GZ3639 and GZT40 was tested on wheat cultivars with various resistance levels by using methods of spray inoculation and injection inoculation with fungal conidia. Under field and greenhouse conditions, strain GZ3639 produced significantly more disease symptoms and reduced more yield than strain GZT40 in all wheat cultivars tested. Conidia of strain GZT40 germinated and infected inoculated spikelets, but disease symptoms were limited to inoculated spikelets without spread to uninoculated spikelets. When strain GZT40 was inoculated using the spray method, multiple initial infection sites in a spike resulted in higher levels of disease symptoms than in spikes ino...
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Gibberella zeae causes wheat ear blight and produces trichothecene toxins in infected grain. In previous studies, trichothecene production in this fungus was disabled by specific disruption of the trichodiene synthase gene (Tri5) and was... more
Gibberella zeae causes wheat ear blight and produces trichothecene toxins in infected grain. In previous studies, trichothecene production in this fungus was disabled by specific disruption of the trichodiene synthase gene (Tri5) and was restored by two methods: gene reversion and transformation-mediated mutant complementation. In previous field tests of wheat ear blight, trichothecene-nonproducing mutants were less virulent than the wild-type progenitor strain from which they were derived. Trichothecene-producing revertants also were restored to wild-type levels of virulence. In contrast, in the field test of wheat ear blight reported here, trichothecene-producing strains obtained by Tri5 mutant complementation were not restored to wild-type levels of virulence. The complemented mutants showed a slightly reduced radial growth compared to the wild-type strain, but otherwise appeared normal in morphology, pigmentation and sexual fertility. Genetic analysis indicated that the aberrant...
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The single base change at the 94th codon of inhA has been referred to as the event that confers resistance on the drugs isoniazid (INH) and ethionamide (ETH) in Mycobacterium smegmatis and M. bovis. From this observation, it has been... more
The single base change at the 94th codon of inhA has been referred to as the event that confers resistance on the drugs isoniazid (INH) and ethionamide (ETH) in Mycobacterium smegmatis and M. bovis. From this observation, it has been anticipated that some of the INH-resistant clinical isolates of M. tuberculosis would carry missense mutations in the same region of the gene. However, few polymorphisms have been identified in this region among INH-resistant isolates. To understand the molecular basis for M. tuberculosis resistance to INH and ETH. The sequence polymorphism at the 94th codon of inhA among M. tuberculosis isolates from Korea was analyzed by polymerase chain reaction (PCR) cloning and sequence analysis. No nucleotide change at the 94th codon of inhA was detected in any of the 24 INH-resistant isolates analyzed in this study. On the other hand, a point mutation was found exclusively at the regulatory region flanking a putative ribosome-binding site of the inhA locus in 14 ...
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Resistance of plants to parasites is heavily impacted by environmental factors. In this study, we analyzed the survival and development of an avirulent Hessian fly (HF), Mayetiola destructor (Say), population ‘White eye’ on a resistant... more
Resistance of plants to parasites is heavily impacted by environmental factors. In this study, we analyzed the survival and development of an avirulent Hessian fly (HF), Mayetiola destructor (Say), population ‘White eye’ on a resistant wheat cultivar ‘Molly’, and a susceptible cultivar ‘Newton’ exposed to varying periods of 40ºC heat stress. We observed that Molly began to lose resistance when subjected to 3 h heat stress, and the loss of resistance increasingly continued with 6 h of heat stress. When 2 mM salicylic solution (SA) was applied to Molly foliage before heat stress, more plants maintained their resistance than plants without SA application. Our results indicate that short periods of heat stress decreases the effectiveness of wheat resistance against Hessian fly infestation, but the application of SA significantly restores resistance in plants under heat stress.
ABSTRACT Biotic stresses including diseases [leaf, stem and stripe rusts, and wheat streak mosaic virus (WSMV)] and insects [greenbug (GB), Hessian fly (Hf), Russian wheat aphid (RWA) and wheat curl mite (WCM)] significantly affect grain... more
ABSTRACT Biotic stresses including diseases [leaf, stem and stripe rusts, and wheat streak mosaic virus (WSMV)] and insects [greenbug (GB), Hessian fly (Hf), Russian wheat aphid (RWA) and wheat curl mite (WCM)] significantly affect grain yield and end-use quality of hard winter wheat (HWW, Triticum aestivum L.) in the U.S. Great Plains. Many genes or quantitative traits loci (QTL) have been identified for seedling or adult plant resistance to these stresses. Molecular markers for these genes or QTL have been identified using mapping or cloning. This study summarizes the markers associated with various genes including genes or QTL conferring resistances to insects, such as GB (7), RWA (4), Hf (9), and WCM (4) and diseases including leaf, stem and stripe rusts (26) and WSMV (2); genes or QTL for end-use quality traits such as high (3) and low (13) molecular weight glutenin subunits, gliadin (3), polyphenol oxidase (2), granule-bound starch synthase (3), puroindoline (2), and pre-harvesting sprouting (1); genes on rye translocations with 1AL and 1BL; and genes associated with plant height (12) and photoperiod sensitivity (1). A subset of the markers was validated using a set of diverse wheat lines developed by breeding programs in the Great Plains. These analyses showed that most markers are diagnostic in only limited genetic backgrounds. However, some markers developed from the gene sequences or alien fragments are highly diagnostic across various backgrounds, such as Rht-B1, Rht-D1, Ppd-D1, Glu-D1, Glu-A1, and 1AL.1RS. Knowledge of both genotype and phenotype of advanced breeding lines could help breeders to select right parents to integrate various genes into new cultivars and increase the efficiency of wheat breeding.
Tan spot, caused by Pyrenophora tritici-repentis, is an economically important foliar disease of wheat worldwide. Eight races of the pathogen have been characterized on the basis of their ability to cause necrosis or chlorosis in a set of... more
Tan spot, caused by Pyrenophora tritici-repentis, is an economically important foliar disease of wheat worldwide. Eight races of the pathogen have been characterized on the basis of their ability to cause necrosis or chlorosis in a set of differential wheat lines. Race 1 produces two host-selective toxins, Ptr ToxA and Ptr ToxC, that induce necrosis and chlorosis, respectively, on leaves of sensitive wheat genotypes. A population of recombinant inbred lines was developed from a cross between Chinese landrace Wangshuibai (resistant) and Chinese breeding line Ning7840 (highly susceptible) to identify chromosome regions harboring quantitative trait loci (QTL) or genes for tan spot resistance. Plants were inoculated at the four-leaf stage in a greenhouse and percent leaf area diseased was scored 7 days after inoculation. Two QTL for resistance to race 1 were mapped to the short arms of chromosomes 1A and 2B in the population. The QTL on 1AS, designated as QTs.ksu-1AS, showed a major eff...
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ABSTRACT In plant species, construction of framework linkage maps to facilitate quantitative trait loci mapping and molecular breeding has been confined to experimental mapping populations. However, development and evaluation of these... more
ABSTRACT In plant species, construction of framework linkage maps to facilitate quantitative trait loci mapping and molecular breeding has been confined to experimental mapping populations. However, development and evaluation of these populations is detached from breeding efforts for cultivar development. In this study, we demonstrate that dense and reliable linkage maps can be constructed using extant breeding populations derived from a large number of crosses, thus eliminating the need for extraneous population development. Using 565 segregating F-1 progeny from 28 four-way cross breeding populations, a linkage map of the hexaploid wheat genome consisting of 3,785 single nucleotide polymorphism (SNP) loci and 22 simple sequence repeat loci was developed. Map estimation was facilitated by application of mapping algorithms for general pedigrees implemented in the software package CRI-MAP. The developed linkage maps showed high rank-order concordance with a SNP consensus map developed from seven mapping studies. Therefore, the linkage mapping methodology presented here represents a resource efficient approach for plant breeding programs that enables development of dense linkage maps &quot;on the fly&quot; to support molecular breeding efforts.
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AbstractMicroarrays have become an important technology for the global analysis of gene expression in organisms. For discovery of differentially expressed genes, many cDNA microarray experiments gave a fixed threshold based on a fold... more
AbstractMicroarrays have become an important technology for the global analysis of gene expression in organisms. For discovery of differentially expressed genes, many cDNA microarray experiments gave a fixed threshold based on a fold change of signal intensity ...
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Page 1. CULTIVAR Journal of Plant Registrations, Vol. 5, No. 1, January 2011 75 &amp;amp;amp;amp;amp;#x27;NH03614 CL&amp;amp;amp;amp;amp;#x27; (Reg. No. CV-1051, PI 653833) hard red winter wheat (Triticum aestivum L.) was tested... more
Page 1. CULTIVAR Journal of Plant Registrations, Vol. 5, No. 1, January 2011 75 &amp;amp;amp;amp;amp;#x27;NH03614 CL&amp;amp;amp;amp;amp;#x27; (Reg. No. CV-1051, PI 653833) hard red winter wheat (Triticum aestivum L.) was tested under Registration of &amp;amp;amp;amp;amp;#x27;NH03614 CL&amp;amp;amp;amp;amp;#x27; Wheat ...