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1.
Hum Genet ; 138(10): 1171-1182, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31367973

RESUMO

Age-related macular degeneration (AMD) is a leading cause of blindness in the world. While dozens of independent genomic variants are associated with AMD, about one-third of AMD heritability is still unexplained. To identify novel variants and loci for AMD, we analyzed Illumina HumanExome chip data from 87 Amish individuals with early or late AMD, 79 unaffected Amish individuals, and 15 related Amish individuals with unknown AMD affection status. We retained 37,428 polymorphic autosomal variants across 175 samples for association and linkage analyses. After correcting for multiple testing (n = 37,428), we identified four variants significantly associated with AMD: rs200437673 (LCN9, p = 1.50 × 10-11), rs151214675 (RTEL1, p = 3.18 × 10-8), rs140250387 (DLGAP1, p = 4.49 × 10-7), and rs115333865 (CGRRF1, p = 1.05 × 10-6). These variants have not been previously associated with AMD and are not in linkage disequilibrium with the 52 known AMD-associated variants reported by the International AMD Genomics Consortium based on physical distance. Genome-wide significant linkage peaks were observed on chromosomes 8q21.11-q21.13 (maximum recessive HLOD = 4.03) and 18q21.2-21.32 (maximum dominant HLOD = 3.87; maximum recessive HLOD = 4.27). These loci do not overlap with loci previously linked to AMD. Through gene ontology enrichment analysis with ClueGO in Cytoscape, we determined that several genes in the 1-HLOD support interval of the chromosome 8 locus are involved in fatty acid binding and triglyceride catabolic processes, and the 1-HLOD support interval of the linkage region on chromosome 18 is enriched in genes that participate in serine-type endopeptidase inhibitor activity and the positive regulation of epithelial to mesenchymal transition. These results nominate novel variants and loci for AMD that require further investigation.


Assuntos
Amish/genética , Predisposição Genética para Doença , Variação Genética , Degeneração Macular/genética , Locos de Características Quantitativas , Idoso , Idoso de 80 Anos ou mais , Alelos , Biologia Computacional , Feminino , Frequência do Gene , Ontologia Genética , Estudos de Associação Genética , Ligação Genética , Humanos , Indiana , Masculino , Ohio , Linhagem
3.
Adv Exp Med Biol ; 1162: 129-150, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31332737

RESUMO

Cannabinoid use and dependence are heritable traits controlled in part by genetic factors. Despite a high incidence of use worldwide, genes that contribute to the risk of problematic use and dependence remain enigmatic. Here we review human candidate gene association studies, family-based linkage studies, and genome-wide association studies completed within the last two decades. These studies have expanded the list of candidate genes and intervals. However, there is little overlap between studies and generally low reproducibility in independent samples. Reasons for this lack of coherence vary but may depend on low sample size and statistical power, and the fact that most studies leverage populations ascertained for drug dependence other than cannabis. However, recent well-powered studies on lifetime cannabis use demonstrate that the genetic architecture of cannabis use resembles that of other substance use disorders and psychiatric disease in that many small effect genes contribute in an additive fashion. This finding suggests that increasing sample size and more focused recruitment of individuals based on cannabinoid use and dependence will identify more candidate genes. Follow-up of existing high priority candidates in preclinical model systems will facilitate better understanding of the genetic architecture and genetic risk factors for cannabis use and dependence.


Assuntos
Canabinoides/farmacologia , Abuso de Maconha/genética , Ligação Genética , Estudo de Associação Genômica Ampla , Humanos
4.
Plant Dis ; 103(9): 2451-2459, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31322491

RESUMO

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most devastating wheat diseases in Ethiopia. To study virulence genetics of the pathogen, 117 progeny isolates were produced through sexual reproduction of an Ethiopian isolate of the stripe rust pathogen on Berberis holstii plants under controlled conditions. The parental and progeny isolates were characterized by phenotyping on wheat lines carrying single Yr genes for resistance and genotyped using 10 polymorphic simple sequence repeated (SSR) markers. The progeny isolates were classified into 37 virulence phenotypes and 75 multilocus genotypes. The parental isolate and progeny isolates were all avirulent to resistance genes Yr5, Yr10, Yr15, Yr24, Yr32, YrTr1, YrSP, and Yr76 but virulent to Yr1 and Yr2, indicating that the parental isolate was homozygous avirulent or homozygous virulent at these loci. The progeny isolates segregated for virulence to 12 Yr genes. Virulence phenotypes to Yr6, Yr28, Yr43, and Yr44 were controlled by a single dominant gene; those to Yr7, Yr9, Yr17, Yr27, Yr25, Yr31, and YrExp2 were each controlled by two dominant genes; and the virulence phenotype to Yr8 was controlled by two complementary dominant genes. A linkage map was constructed with seven SSR markers, and 16 virulence loci corresponding to 11 Yr resistance genes were mapped with some loci linked to each other. These results are useful in understanding host-pathogen interactions and selecting resistance genes to develop wheat cultivars with highly effective resistance to stripe rust.


Assuntos
Basidiomycota , Berberis , Ligação Genética , Recombinação Genética , Virulência , Basidiomycota/genética , Basidiomycota/patogenicidade , Berberis/genética , Etiópia , Doenças das Plantas , Triticum/microbiologia , Virulência/genética
5.
BMC Plant Biol ; 19(1): 249, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31185908

RESUMO

BACKGROUND: As an elite japonica rice variety, Kongyu-131 has been cultivated for over 20 years in the third accumulated temperature zone of Heilongjiang Province, China. However, the cultivated area of Kongyu-131 has decreased each year due to extensive outbreaks of rice blast. To achieve the goals of improving blast resistance and preserving other desirable traits in Kongyu-131, a genome-updating method similar to repairing a bug in a computer program was adopted in this study. A new allele of the broad-spectrum blast resistance gene pi21 in the upland rice variety GKGH was mined by genetic analysis and introgressed into the genome of Kongyu-131 to upgrade its blast resistance. RESULT: QTL analysis was performed with an F2 population derived from a cross between Kongyu-131 and GKGH, and a blast resistance QTL was detected near the pi21 locus. Parental Pi21 sequence alignment showed that the pi21 of the donor (GKGH) was a new allele. By 5 InDel or SNP markers designed based on the sequence within and around pi21, the introgressed chromosome segment was shortened to less than 634 kb to minimize linkage drag by screening recombinants in the target region. The RRPG was 99.92%, calculated according to 201 SNP markers evenly distributed on 12 chromosomes. Artificial inoculation at the seedling stage showed that the blast resistance of the new Kongyu-131 was improved significantly. Field experiments also indicated that the improved Kongyu-131 had enhanced field resistance to rice blast and grain-quality traits similar to those of the original Kongyu-131. CONCLUSIONS: It is feasible to improve resistance to rice blast and preserve other desirable traits by precisely improving the Pi21 locus of Kongyu-131. Linkage drag can be eliminated effectively via recombinant selection on both sides of the target gene.


Assuntos
Resistência à Doença/genética , Genes de Plantas , Oryza/genética , Doenças das Plantas/genética , Proteínas de Plantas/genética , Ligação Genética , Magnaporthe/fisiologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo
6.
BMC Genomics ; 20(1): 437, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31146687

RESUMO

BACKGROUND: For spring-type Chinese cabbage production, premature bolting refers to the excessive elongation of dwarf stems before harvesting. Although quantitative trait loci (QTL) mapping for bolting-related traits have been studied extensively, the main flower stalk length (MFSL) have been rarely investigated. Two inbred lines, 06-247 and He102, have significant differences in the MFSL. In this study, these two materials were selected as parental lines for the construction of a recombinant inbred line (RIL) mapping population. High-density mapping of QTL for the MFSL was performed based on the deep resequencing of parental lines and specific locus-amplified fragment sequencing (SLAF-Seq) of individual recombination inbred lines. RESULTS: An F7 population consisting of 150 lines was developed. Deep resequencing of parental lines produced 21.08 gigabases, whereas SLAF-Seq produced an average of 428.35 million bases for each progeny. The total aligned data from the parental lines identified 1,082,885 high-quality single nucleotide polymorphisms (SNPs) between parental lines. Out of these, 5392 SNP markers with a segregation type of aa×bb and average integrity of > 99% were suitable for the genetic linkage map construction. The final map contained 10 linkage groups (LGs) was 1687.82 cM in length with an average distance of 0.32 cM between adjacent markers. Based on the high-density map, nine QTLs for MFSL were found to be distributed on seven chromosomes, and two major-effect QTLs were identified for the first time. The physical distance between adjacent markers of two major-effect QTLs was 44.37 kbp and 121.91 kbp, respectively. Approximately 2056 and 6769 SNP markers within confidence intervals were identified according to the results of parental line resequencing, which involved 24 and 199 mutant genes. CONCLUSIONS: The linkage map constructed in this study has the highest density in Chinese cabbage to date. Two major-effect QTLs for MFSL in Chinese cabbage were also identified. Among these, a novel QTL associated with bolting mapped on LG A04 was identified based on MFSL. The results of this study provide an important platform for gene/QTL mapping and marker-assisted selection (MAS) breeding for bolting-resistant Chinese cabbage.


Assuntos
Brassica rapa/genética , Locos de Características Quantitativas , Brassica rapa/anatomia & histologia , Mapeamento Cromossômico , Ligação Genética , Técnicas de Genotipagem , Sequenciamento de Nucleotídeos em Larga Escala , Fenótipo , Caules de Planta/anatomia & histologia , Polimorfismo de Nucleotídeo Único
7.
Plant Sci ; 285: 122-131, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203876

RESUMO

Domestication and subsequent breeding have eroded genetic diversity in the modern chickpea crop by ˜100-fold. Corresponding reductions to trait variation create the need, and an opportunity, to identify and harness the genetic capacity of wild species for crop improvement. Here we analyze trait segregation in a series of wild x cultivated hybrid populations to delineate the genetic underpinnings of domestication traits. Two species of wild chickpea, C. reticulatum and C. echinospermum, were crossed with the elite, early flowering C. arietinum cultivar ICCV96029. KASP genotyping of F2 parents with an FT-linked molecular marker enabled selection of 284 F3 families with reduced phenological variation: 255 F3 families of C. arietinum x reticulatum (AR) derived from 17 diverse wild parents and 29 F3 families of C. arietinum x echinospermum (AE) from 3 wild parents. The combined 284 lineages were genotyped using a genotyping-by-sequencing strategy and phenotyped for agronomic traits. 50 QTLs in 11 traits were detected from AR and 35 QTLs in 10 traits from the combined data. Using hierarchical clustering to assign traits to six correlated groups and mixed model based multi-trait mapping, four pleiotropic loci were identified. Bayesian analysis further identified four inter-trait relationships controlling the duration of vegetative growth and seed maturation, for which the underlying pleiotropic genes were mapped. A random forest approach was used to explore the most extreme trait differences between AR and AE progenies, identifying traits most characteristic of wild species origin. Knowledge of the genomic basis of traits that segregate in wild-cultivated hybrid populations will facilitate chickpea improvement by linking genetic and phenotypic variation in a quantitative genetic framework.


Assuntos
Cicer/genética , Genes de Plantas/genética , Melhoramento Vegetal/métodos , Teorema de Bayes , Cicer/crescimento & desenvolvimento , DNA de Plantas/genética , Domesticação , Estudos de Associação Genética , Ligação Genética/genética , Hibridização Genética/genética , Locos de Características Quantitativas/genética , Característica Quantitativa Herdável , Sementes/crescimento & desenvolvimento
8.
J Dairy Sci ; 102(7): 6263-6275, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31103297

RESUMO

Domestic yaks (Bos grunniens) and domestic Taurus cattle (Bos taurus) are closely related. An interesting phenomenon in interspecific crossings is male sterility in the F1 hybrid (yattle) and F2 backcross, with no late meiotic cells or spermatids in the seminiferous tubules. The mammalian Y chromosome is crucial for spermatogenesis and male fertility. This study investigated the copy number variations and mRNA of Y-transitional region genes TSPY2 (testis specific protein, Y-linked 2 and testis-specific Y-encoded protein 3-like) and PRAMEY (preferentially expressed antigen in melanoma, Y-linked), and Y-ampliconic region genes TSPY (testis-specific Y-encoded protein 1-like), ZNF280BY (zinc finger protein 280B, Y-linked) and HSFY (heat-shock transcription factor, Y-linked) in mature testes from Taurus cattle, yaks, and yattle. Phylogenetic trees divided 33 copies of TSPY into major 2 types (TSPY-T1 and TSPY-T2), 19 copies of TSPY2 into 2 types (TSPY2-T1 and T2), and 8 copies of PRAMEY into 4 types (PRAMEY-T1 to T4). Searching by the Basic Local Alignment Search Tool of the TSPY2 coding sequences in GenBank revealed that TSPY2 was conserved in Bovidae. The TSPY2-T2 sequences were absent, whereas PRAMEY-T2 and PRAMEY-T4 were amplified on the yak Y chromosome. The average copy numbers of TSPY-T2 and ZNF280BY were significantly different between cattle and yaks. The TSPY-T2, TSPY2, PRAMEY, ZNF280BY, and HSFY genes were uniquely or predominantly expressed in testes. Reverse-transcription quantitative PCR showed that the TSPY-T2, PRAMEY-T2, HSFY, ZNF280BY, protamine 1 (PRM1), and protamine 2 (PRM2) genes were almost not expressed in yattle. The PRM1 and PRM2 genes are used as positive markers for spermatozoa. Thus, our results showed that the genomic structure of the Y-transitional and Y-ampliconic region differed between Taurus cattle and yaks. Dysregulated expression of Y-ampliconic region genes TSPY-T2, HSPY, ZNF280BY, and Y-transitional region gene PRAMEY-T2 may be associated with hybrid male sterility in yattle.


Assuntos
Antígenos de Neoplasias/genética , Bovinos/genética , Proteínas de Ciclo Celular/genética , Ligação Genética/genética , Hibridização Genética/genética , Cromossomo Y/genética , Animais , Cruzamentos Genéticos , Variações do Número de Cópias de DNA , Expressão Gênica , Regulação da Expressão Gênica , Variação Genética/genética , Infertilidade Masculina/genética , Masculino , Filogenia , RNA Mensageiro/análise , Espermatogênese/genética , Testículo/metabolismo
9.
J Immunol Res ; 2019: 5298792, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31049358

RESUMO

AIRmax and AIRmin mouse strains phenotypically selected for high and low acute inflammatory responsiveness (AIR) are, respectively, susceptible or resistant to developing hepatocellular carcinoma (HCC) induced by the chemical carcinogens urethane and diethylnitrosamine (DEN). Early production of TNF-α, IL-1ß, and IL-6 in the liver after DEN treatment correlated with tumor development in AIRmax mice. Transcriptome analysis of livers from untreated AIRmax and AIRmin mice showed specific gene expression profiles in each line, which might play a role in their differential susceptibility to HCC. Linkage analysis with SNP markers in F2 (AIRmax×AIRmin) intercross mice revealed two quantitative trait loci (QTL) in chromosomes 2 and 9, which are significantly associated with the number and progression of urethane-induced liver tumors. An independent linkage analysis with an intercross population from A/J and C57BL/6J inbred mice mapped regions in chromosomes 1 and 7 associated with the progression of urethane-induced liver tumors, evidencing the heterogeneity of HCC genetic control.


Assuntos
Animais não Endogâmicos , Carcinoma Hepatocelular/genética , Predisposição Genética para Doença , Inflamação/imunologia , Neoplasias Hepáticas/genética , Alelos , Animais , Carcinogênese/genética , Carcinoma Hepatocelular/imunologia , Modelos Animais de Doenças , Ligação Genética , Endogamia , Inflamação/genética , Interleucina-1beta/genética , Interleucina-6/genética , Neoplasias Hepáticas/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Locos de Características Quantitativas , Transcriptoma , Fatores de Necrose Tumoral/genética
10.
BMC Genomics ; 20(1): 343, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31064320

RESUMO

BACKGROUND: Caixin and Zicaitai (Brassica rapa) belong to Southern and Central China respectively. Zicaitai contains high amount of anthocyanin in leaf and stalk resulting to the purple color. Stalk is the major edible part and stalk color is an economically important trait for the two vegetables. The aim of this study is to construct a high density genetic map using the specific length amplified fragment sequencing (SLAF-seq) technique to explore genetic basis for anthocyanin pigmentation traits via quantitative trait loci (QTL) mapping. RESULTS: We constructed a high generation linkage map with a mapping panel of F2 populations derived from 150 individuals of parental lines "Xianghongtai 01" and "Yinong 50D" with purple and green stalk respectively. The map was constructed containing 4253 loci, representing 10,940 single nucleotide polymorphism (SNP) markers spanning 1030.04 centiMorgans (cM) over 10 linkage groups (LGs), with an average distance between markers of 0.27 cM. Quantitative trait loci (QTL) analysis revealed that a major locus on chromosome 7 and 4 minor QTLs explaining 2.69-61.21% of phenotypic variation (PVE) were strongly responsible for variation in stalk color trait. Bioinformatics analysis of the major locus identified 62 protein-coding genes. Among the major locus, there were no biosynthetic genes related to anthocyanin. However, there were several transcription factors like helix-loop-helix (bHLH) bHLH, MYB in the locus. Seven predicted candidate genes were selected for the transcription level analysis. Only bHLH49 transcription factor, was significantly higher expressed in both stalks and young leaves of Xianghongtai01 than Yinong50D. An insertion and deletion (InDel) marker developed from deletion/insertion in the promoter region of bHLH49 showed significant correlation with the stalk color trait in the F2 population. CONCLUSION: Using the constructed high-qualified linkage map, this study successfully identified QTLs for stalk color trait. The identified valuable markers and candidate genes for anthocyanin accumulation in stalk will provide useful information for molecular regulation of anthocyanin biosynthesis. Overall our findings will lay a foundation for functional gene cloning, marker-assisted selection (MAS) and molecular breeding of important economic traits in B. rapa.


Assuntos
Antocianinas/metabolismo , Brassica rapa/anatomia & histologia , Brassica rapa/genética , Cromossomos de Plantas , Locos de Características Quantitativas , Brassica rapa/crescimento & desenvolvimento , Mapeamento Cromossômico , Ligação Genética , Marcadores Genéticos , Técnicas de Genotipagem , Fenótipo , Pigmentação , Análise de Sequência de DNA
11.
BMC Genomics ; 20(1): 331, 2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31046664

RESUMO

BACKGROUND: Both a source of diversity and the development of genomic tools, such as reference genomes and molecular markers, are equally important to enable faster progress in plant breeding. Pear (Pyrus spp.) lags far behind other fruit and nut crops in terms of employment of available genetic resources for new cultivar development. To address this gap, we designed a high-density, high-efficiency and robust single nucleotide polymorphism (SNP) array for pear, with the main objectives of conducting genetic diversity and genome-wide association studies. RESULTS: By applying a two-step design process, which consisted of the construction of a first 'draft' array for the screening of a small subset of samples, we were able to identify the most robust and informative SNPs to include in the Applied Biosystems™ Axiom™ Pear 70 K Genotyping Array, currently the densest SNP array for pear. Preliminary evaluation of this 70 K array in 1416 diverse pear accessions from the USDA National Clonal Germplasm Repository (NCGR) in Corvallis, OR identified 66,616 SNPs (93% of all the tiled SNPs) as high quality and polymorphic (PolyHighResolution). We further used the Axiom Pear 70 K Genotyping Array to construct high-density linkage maps in a bi-parental population, and to make a direct comparison with available genotyping-by-sequencing (GBS) data, which suggested that the SNP array is a more robust method of screening for SNPs than restriction enzyme reduced representation sequence-based genotyping. CONCLUSIONS: The Axiom Pear 70 K Genotyping Array, with its high efficiency in a widely diverse panel of Pyrus species and cultivars, represents a valuable resource for a multitude of molecular studies in pear. The characterization of the USDA-NCGR collection with this array will provide important information for pear geneticists and breeders, as well as for the optimization of conservation strategies for Pyrus.


Assuntos
Mapeamento Cromossômico/métodos , Ligação Genética , Marcadores Genéticos , Genoma de Planta , Polimorfismo de Nucleotídeo Único , Pyrus/genética , Sementes/genética , Cromossomos de Plantas , Estudo de Associação Genômica Ampla , Técnicas de Genotipagem
12.
BMC Genomics ; 20(1): 371, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088355

RESUMO

BACKGROUND: Barbarea vulgaris is a wild cruciferous plant and include two distinct types: the G- and P-types named after their glabrous and pubescent leaves, respectively. The types differ significantly in resistance to a range of insects and diseases as well as glucosinolates and other chemical defenses. A high-density linkage map was needed for further progress to be made in the molecular research of this plant. RESULTS: We performed restriction site-associated DNA sequencing (RAD-Seq) on an F2 population generated from G- and P-type B. vulgaris. A total of 1545 SNP markers were mapped and ordered in eight linkage groups, which represents the highest density linkage map to date for the crucifer tribe Cardamineae. A total of 722 previously published genome contigs (50.2 Mb, 30% of the total length) can be anchored to this high density genetic map, an improvement compared to a previously published map (431 anchored contigs, 38.7 Mb, 23% of the assembly genome). Most of these (572 contigs, 31.2 Mb) were newly anchored to the map, representing a significant improvement. On the basis of the present high-density genetic map, 37 QTL were detected for eleven traits, each QTL explaining 2.9-71.3% of the phenotype variation. QTL of glucosinolates, leaf size and color traits were in most cases overlapping, possibly implying a functional connection. CONCLUSIONS: This high-density linkage map and the QTL obtained in this study will be useful for further understanding of the genetic of the B. vulgaris and molecular basis of these traits, many of which are shared in the related crop watercress.


Assuntos
Barbarea/genética , Mapeamento Cromossômico/métodos , Locos de Características Quantitativas , Análise de Sequência de DNA/métodos , Barbarea/fisiologia , DNA de Plantas/genética , Ligação Genética , Fenótipo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Polimorfismo de Nucleotídeo Único
13.
Int J Mol Sci ; 20(9)2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31058828

RESUMO

In plants, lesion mimic mutants (LMMs) reveal spontaneous disease-like lesions in the absence of pathogen that constitutes powerful genetic material to unravel genes underlying programmed cell death (PCD), particularly the hypersensitive response (HR). However, only a few LMMs are reported in soybean, and no related gene has been cloned until now. In the present study, we isolated a new LMM named spotted leaf-1 (spl-1) from NN1138-2 cultivar through ethyl methanesulfonate (EMS) treatment. The present study revealed that lesion formation might result from PCD and excessive reactive oxygen species (ROS) accumulation. The chlorophyll content was significantly reduced but antioxidant activities, viz., superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), as well as the malondialdehyde (MDA) contents, were detected higher in spl-1 than in the wild-type. According to segregation analysis of mutant phenotype in two genetic populations, viz., W82×spl-1 and PI378692×spl-1, the spotted leaf phenotype of spl-1 is controlled by a single recessive gene named lm1. The lm1 locus governing mutant phenotype of spl-1 was first identified in 3.15 Mb genomic region on chromosome 04 through MutMap analysis, which was further verified and fine mapped by simple sequence repeat (SSR) marker-based genetic mapping. Genetic linkage analysis narrowed the genomic region (lm1 locus) for mutant phenotype to a physical distance of ~76.23 kb. By searching against the Phytozome database, eight annotated candidate genes were found within the lm1 region. qRT-PCR expression analysis revealed that, among these eight genes, only Glyma.04g242300 showed highly significant expression levels in wild-type relative to the spl-1 mutant. However, sequencing data of the CDS region showed no nucleotide difference between spl-1 and its wild type within the coding regions of these genes but might be in the non-coding regions such as 5' or 3' UTR. Hence, the data of the present study are in favor of Glyma.04g242300 being the possible candidate genes regulating the mutant phenotype of spl-1. However, further validation is needed to prove this function of the gene as well as its role in PCD, which in turn would be helpful to understand the mechanism and pathways involved in HR disease resistance of soybean.


Assuntos
Mapeamento Cromossômico , Fenótipo , Folhas de Planta/genética , Proteínas de Plantas/genética , Soja/genética , Biomarcadores , Fenômenos Químicos , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Ligação Genética , Marcadores Genéticos , Mutação , Pigmentos Biológicos , Folhas de Planta/química , Característica Quantitativa Herdável , Soja/química
14.
BMC Plant Biol ; 19(1): 183, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31060503

RESUMO

BACKGROUND: Triticum timopheevii (2n = 4x = 28; AtAtGG), is an important source for new genetic variation for wheat improvement with genes for potential disease resistance and salt tolerance. By generating a range of interspecific hybrid lines, T. timopheevii can contribute to wheat's narrow gene-pool and be practically utilised in wheat breeding programmes. Previous studies that have generated such introgression lines between wheat and its wild relatives have been unable to use high-throughput methods to detect the presence of wild relative segments in such lines. RESULTS: A whole genome introgression approach, exploiting homoeologous recombination in the absence of the Ph1 locus, has resulted in the transfer of different chromosome segments from both the At and G genomes of T. timopheevii into wheat. These introgressions have been detected and characterised using single nucleotide polymorphism (SNP) markers present on a high-throughput Axiom® Genotyping Array. The analysis of these interspecific hybrid lines has resulted in the detection of 276 putative unique introgressions from T. timopheevii, thereby allowing the generation of a genetic map of T. timopheevii containing 1582 SNP markers, spread across 14 linkage groups representing each of the seven chromosomes of the At and G genomes of T. timopheevii. The genotyping of the hybrid lines was validated through fluorescence in situ hybridisation (FISH). Comparative analysis of the genetic map of T. timopheevii and the physical map of the hexaploid wheat genome showed that synteny between the two species is highly conserved at the macro-level and confirmed the presence of inter- and intra-genomic translocations within the At and G genomes of T. timopheevii that have been previously only detected through cytological techniques. CONCLUSIONS: In this work, we report a set of SNP markers present on a high-throughput genotyping array, able to detect the presence of T. timopheevii in a hexaploid wheat background making it a potentially valuable tool for marker assisted selection (MAS) in wheat pre-breeding programs. These valuable resources of high-density molecular markers and wheat-T. timopheevii hybrid lines will greatly enhance the work being undertaken for wheat improvement through wild relative introgressions.


Assuntos
Genoma de Planta , Hibridização Genética , Poliploidia , Triticum/genética , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Cruzamentos Genéticos , Ecótipo , Ligação Genética , Loci Gênicos , Marcadores Genéticos , Genótipo , Polimorfismo de Nucleotídeo Único/genética , Recombinação Genética/genética , Sementes/genética , Especificidade da Espécie
15.
BMC Plant Biol ; 19(1): 167, 2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31035914

RESUMO

BACKGROUND: First flower node (FFN) is an important trait for evaluating fruit earliness in pepper (Capsicum annuum L.). The trait is controlled by quantitative trait loci (QTL); however, studies have been limited on QTL mapping and genes contributing to the trait. RESULTS: In this study, we developed a high density genetic map using specific-locus amplified fragment sequencing (SLAF-seq), a high-throughput strategy for de novo single nucleotide polymorphism discovery, based on 146 recombinant inbred lines (RILs) derived from an intraspecific cross between PM702 and FS871. The map contained 9328 SLAF markers on 12 linkage groups (LGs), and spanned a total genetic distance of 2009.69 centimorgan (cM) with an average distance of 0.22 cM. The sequencing depth for the map was 72.39-fold in the male parent, 57.04-fold in the female parent, and 15.65-fold in offspring. Using the genetic map, two major QTLs, named Ffn2.1 and Ffn2.2, identified on LG02 were strongly associated with FFN, with a phenotypic variance explanation of 28.62 and 19.56%, respectively. On the basis of the current annotation of C. annuum cv. Criollo de Morelos (CM334), 59 candidate genes were found within the Ffn2.1 and Ffn2.2 region, but only 3 of 59 genes were differentially expressed according to the RNA-seq results. Eventually we identified one gene associated with the FFN based on the function through GO, KEGG, and Swiss-prot analysis. CONCLUSIONS: Our research showed that the construction of high-density genetic map using SLAF-seq is a valuable tool for fine QTL mapping. The map we constructed is by far the most saturated complete genetic map of pepper, and using it we conducted fine QTL mapping for the important trait, FFN. QTLs and candidate genes obtained in this study lay a good foundation for the further research on FFN-related genes and other genetic applications in pepper.


Assuntos
Capsicum/genética , Mapeamento Cromossômico/métodos , Cromossomos de Plantas , Flores/genética , Locos de Características Quantitativas , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Ligação Genética , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Polimorfismo de Nucleotídeo Único
16.
Planta ; 250(1): 129-143, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30944981

RESUMO

MAIN CONCLUSION: In wheat, a QTL QTrl.saw-2D.2 associated with the total root length was identified, presumably containing genes closely related to root development. A mapping population of 184 recombinant inbred lines derived from the cross SY95-71 × CH7034 was used to map QTL for seedling root characteristics in hydroponic culture (HC) and in soil-filled pot (SP) methods. Four traits, including maximum root length (MRL), root number (RN), total length (TRL), and root diameter (RD) were measured and used in QTL analyses. A total of 33 QTL for the four root traits were detected, 17 QTLs for TRL, six for RN, seven for MRL, and three for RD. Seven QTL were detected in both HC and SP methods, which explained 7-18% phenotypic variation. One QTL QTrl.saw-2D.2 detected in both HC and SP methods was also validated in another population comprised of 215 diverse lines. This QTL is a novel QTL that explained the highest phenotypic variation 18% in all QTL identified in the present study. Based on candidate gene and comparative genomics analyses, the QTL QTrl.saw-2D.2 may contain genes closely related to root development in wheat (Triticum aestivum L.). The two candidate genes were proposed to explore in future studies.


Assuntos
Locos de Características Quantitativas/genética , Triticum/genética , Mapeamento Cromossômico , Secas , Ligação Genética , Estudo de Associação Genômica Ampla , Fenótipo , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/fisiologia , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Triticum/crescimento & desenvolvimento , Triticum/fisiologia
17.
Int J Mol Sci ; 20(8)2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31013701

RESUMO

Phytophthora root rot (PRR) causes serious annual soybean yield losses worldwide. The most effective method to prevent PRR involves growing cultivars that possess genes conferring resistance to Phytophthora sojae (Rps). In this study, QTL-sequencing combined with genetic mapping was used to identify RpsX in soybean cultivar Xiu94-11 resistance to all P. sojae isolates tested, exhibiting broad-spectrum PRR resistance. Subsequent analysis revealed RpsX was located in the 242-kb genomic region spanning the RpsQ locus. However, a phylogenetic investigation indicated Xiu94-11 carrying RpsX is distantly related to the cultivars containing RpsQ, implying RpsX and RpsQ have different origins. An examination of candidate genes revealed RpsX and RpsQ share common nonsynonymous SNP and a 144-bp insertion in the Glyma.03g027200 sequence encoding a leucine-rich repeat (LRR) region. Glyma.03g027200 was considered to be the likely candidate gene of RpsQ and RpsX. Sequence analyses confirmed that the 144-bp insertion caused by an unequal exchange resulted in two additional LRR-encoding fragments in the candidate gene. A marker developed based on the 144-bp insertion was used to analyze the genetic population and germplasm, and proved to be useful for identifying the RpsX and RpsQ alleles. This study implies that the number of LRR units in the LRR domain may be important for PRR resistance in soybean.


Assuntos
Resistência à Doença/genética , Interações Hospedeiro-Parasita/genética , Phytophthora , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Soja/genética , Soja/parasitologia , Mapeamento Cromossômico , Cromossomos de Plantas , Sequência Conservada , Genes de Plantas , Ligação Genética , Loci Gênicos , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Phytophthora/isolamento & purificação , Polimorfismo de Nucleotídeo Único , Soja/classificação
18.
Int J Mol Sci ; 20(7)2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30965578

RESUMO

The identification of gene(s) that are involved in Cd accumulation/tolerance is vital in developing crop cultivars with low Cd accumulation. We developed a doubled haploid (DH) population that was derived from a cross of Suyinmai 2 (Cd-sensitive) × Weisuobuzhi (Cd-tolerant) to conduct quantitative trait loci (QTL) mapping studies. We assessed chlorophyll content, traits that are associated with development, metal concentration, and antioxidative enzyme activity in DH population lines and parents under control and Cd stress conditions. A single QTL, designated as qShCd7H, was identified on chromosome 7H that was linked to shoot Cd concentration; qShCd7H explained 17% of the phenotypic variation. Comparative genomics, map-based cloning, and gene silencing were used in isolation, cloning, and functional characterization of the candidate gene. A novel gene HvPAA1, being related to shoot Cd concentration, was identified from qShCd7H. Sequence comparison indicated that HvPAA1 carried seven domains with an N-glycosylation motif. HvPAA1 is predominantly expressed in shoots. Subcellular localization verified that HvPAA1 is located in plasma membrane. The silencing of HvPAA1 resulted in growth inhibition, greater Cd accumulation, and a significant decrease in Cd tolerance. We conclude HvPAA1 is a novel plasma membrane-localized ATPase that contributes to Cd tolerance and accumulation in barley. The results provide us with new insights that may aid in the screening and development of Cd-tolerant and low-Cd-accumulation crops.


Assuntos
Adenosina Trifosfatases/metabolismo , Cádmio/metabolismo , Hordeum/metabolismo , Adenosina Trifosfatases/genética , Cromossomos de Plantas/genética , Ligação Genética , Haploidia , Fenótipo , Locos de Características Quantitativas/genética
19.
Mamm Genome ; 30(3-4): 63-70, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30972478

RESUMO

We constructed a high-density genetic map for Mongolian gerbils (Meriones unguiculatus). We genotyped 137 F2 individuals with a genotype-by-sequencing (GBS) approach at over 10,000 loci and built the genetic map using a two-step approach. First, we chose the highest-quality set of 485 markers to construct a robust map of 1239 cM with 22 linkage groups as expected from the published karyotype. Second, we added an additional 5449 markers onto the map based on their genotype similarity with the original markers. We used the final marker set to assemble 1140 genomic scaffolds (containing ~ 20% of annotated genes) into a chromosome-level assembly. We used both genetic linkage and relative sequencing coverage in males and females to identify X- and Y-chromosome scaffolds and from these we designed a robust and internally-controlled PCR assay to determine sex. This assay will facilitate early stage sex-typing of embryonic and young gerbils which is difficult using current visual methods. Accession ID: Meriones unguiculatus: 10047.


Assuntos
Gerbillinae/genética , Cromossomos Sexuais/genética , Animais , Mapeamento Cromossômico , Feminino , Ligação Genética , Marcadores Genéticos , Genoma , Genômica , Masculino , Tipagem Molecular , Polimorfismo de Nucleotídeo Único
20.
BMC Plant Biol ; 19(1): 165, 2019 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-31029106

RESUMO

BACKGROUND: Alfalfa (Medicago sativa L.) is an important forage crop grown worldwide. Alfalfa is called the "queen of forage crops" due to its high forage yield and nutritional characteristics. The aim of this study was to undertake quantitative trait loci (QTL) mapping of yield and yield-related traits in an F1 population of two alfalfa varieties that differ in their yield and yield-related traits. RESULTS: We constructed a high-density linkage map using single nucleotide polymorphism (SNP) markers generated by restriction-site associated DNA sequencing (RAD-seq). The linkage map contains 4346 SNP and 119 simple sequence repeat (SSR) markers, with 32 linkage groups for each parent. The average marker distances were 3.00 and 1.32 cM, with coverages of 3455 cM and 4381 cM for paternal and maternal linkage maps, respectively. Using these maps and phenotypic data, we identified a total of 21 QTL for yield and yield components, including five for yield, five for plant height, five for branch number, and six for shoot diameter. Among them, six QTL were co-located for more than one trait. Five QTL explained more than 10% of the phenotypic variation. CONCLUSIONS: We used RAD-seq to construct a linkage map for alfalfa that greatly enhanced marker density compared to previous studies. This high-density linkage map of alfalfa is a useful reference for mapping yield-related traits. Identified yield-related loci could be used to validate their usefulness in developing markers for maker-assisted selection in breeding populations to improve yield potential in alfalfa.


Assuntos
Mapeamento Cromossômico , Ligação Genética , Medicago sativa/genética , Locos de Características Quantitativas/genética , Análise de Sequência de DNA , Tetraploidia , Análise de Variância , Cruzamentos Genéticos , Haplótipos/genética , Medicago sativa/anatomia & histologia , Fenótipo , Brotos de Planta/anatomia & histologia , Polimorfismo de Nucleotídeo Único/genética
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