scholarly journals Genome-Wide Introgression and Quantitative Trait Locus Mapping Reveals the Potential of Asian Cotton (Gossypium arboreum) in Improving Upland Cotton (Gossypium hirsutum)

2021 ◽  
Vol 12 ◽  
Author(s):  
Liuchun Feng ◽  
Yu Chen ◽  
Min Xu ◽  
Ying Yang ◽  
Haoran Yue ◽  
...  

Gossypium arboreum (2n=2x=26, A2), the putative progenitor of the At-subgenome of Gossypium hirsutum (2n=4x=52, AD), is a repository of genes of interesting that have been eliminated during evolution/domestication of G. hirsutum. However, its valuable genes remain untapped so far due to species isolation. Here, using a synthetic amphiploid (AADDA2A2) previously reported, we developed a set of 289 G. arboreum chromosome segment introgression lines (ILs) in G. hirsutum by expanding the backcrossing population and through precise marker-assisted selection (MAS) although complex chromosomal structural variations existed between parents which severely hindered introgression. Our results showed the total coverage length of introgressed segments was 1,116.29 Mb, representing 78.48% of the At-subgenome in the G. hirsutum background, with an average segment-length of 8.69 Mb. A total of 81 co- quantitative trait loci (QTLs) for yield and fiber quality were identified by both the RSTEP-ADD-based QTL mapping and the genome-wide association study (GWAS) analysis, with 1.01–24.78% of the phenotypic variance explained. Most QTLs for boll traits showed negative additive effects, but G. arboreum still has the potential to improve boll-number traits in G. hirsutum. Most QTLs for fiber quality showed negative additive effects, implying these QTLs were domesticated in G. hirsutum compared with G. arboreum and, a small quantity of fiber quality QTLs showing positive additive effects, conversely; however, indicates that G. arboreum has the underlying genes of enhancing fiber quality of G. hirsutum. This study provides new insights into the breeding genetic potential of G. arboreum, lays the foundation for further mining favorable genes of interest, and provides guidance for inter-ploidy gene transference from relatives into cultivated crops.

2021 ◽  
Vol 12 ◽  
Author(s):  
Zareen Sarfraz ◽  
Muhammad Shahid Iqbal ◽  
Xiaoli Geng ◽  
Muhammad Sajid Iqbal ◽  
Mian Faisal Nazir ◽  
...  

For about a century, plant breeding has widely exploited the heterosis phenomenon–often considered as hybrid vigor–to increase agricultural productivity. The ensuing F1 hybrids can substantially outperform their progenitors due to heterozygous combinations that mitigate deleterious mutations occurring in each genome. However, only fragmented knowledge is available concerning the underlying genes and processes that foster heterosis. Although cotton is among the highly valued crops, its improvement programs that involve the exploitation of heterosis are still limited in terms of significant accomplishments to make it broadly applicable in different agro-ecological zones. Here, F1 hybrids were derived from mating a diverse Upland Cotton germplasm with commercially valuable cultivars in the Line × Tester fashion and evaluated across multiple environments for 10 measurable traits. These traits were dissected into five different heterosis types and specific combining ability (SCA). Subsequent genome-wide predictions along-with association analyses uncovered a set of 298 highly significant key single nucleotide polymorphisms (SNPs)/Quantitative Trait Nucleotides (QTNs) and 271 heterotic Quantitative Trait Nucleotides (hQTNs) related to agronomic and fiber quality traits. The integration of a genome wide association study with RNA-sequence analysis yielded 275 candidate genes in the vicinity of key SNPs/QTNs. Fiber micronaire (MIC) and lint percentage (LP) had the maximum number of associated genes, i.e., each with 45 related to QTNs/hQTNs. A total of 54 putative candidate genes were identified in association with HETEROSIS of quoted traits. The novel players in the heterosis mechanism highlighted in this study may prove to be scientifically and biologically important for cotton biologists, and for those breeders engaged in cotton fiber and yield improvement programs.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pengpeng Wang ◽  
Shoupu He ◽  
Gaofei Sun ◽  
Zhaoe Pan ◽  
Junling Sun ◽  
...  

AbstractUpland cotton (Gossypium hirsutum L.) is an important economic crop for renewable textile fibers. However, the simultaneous improvement of yield and fiber quality in cotton is difficult as the linkage drag. Compared with breaking the linkage drag, identification of the favorable pleiotropic loci on the genome level by genome-wide association study (GWAS) provides a new way to improve the yield and fiber quality simultaneously. In our study restriction-site-associated DNA sequencing (RAD-seq) was used to genotype 316 cotton accessions. Eight major traits in three categories including yield, fiber quality and maturation were investigated in nine environments (3 sites × 3 years). 231 SNPs associated with these eight traits (− log10(P) > 5.27) were identified, located in 27 genomic regions respectively by linkage disequilibrium analysis. Further analysis showed that four genomic regions (the region 1, 6, 8 and 23) held favorable pleiotropic loci and 6 candidate genes were identified. Through genotyping, 14 elite accessions carrying the favorable loci on four pleiotropic regions were identified. These favorable pleiotropic loci and elite genotypes identified in this study will be utilized to improve the yield and fiber quality simultaneously in future cotton breeding.


2020 ◽  
Vol 71 (10) ◽  
pp. 884
Author(s):  
Zhikun Wang ◽  
Mingming Yang ◽  
Yuanzhuo Wang ◽  
Chao Yang ◽  
Xue Zhao ◽  
...  

Association analysis is an alternative to conventional, family-based methods for detecting the location of gene(s) or quantitative trait loci (QTLs), and provides relatively high resolution in terms of defining the genome position of a gene or QTL. Flavour is an essential quality characteristic of soymilk; however, soymilk contains volatile compounds unacceptable to consumers. One of main constituents in the volatiles of normal soymilk is 2-heptenal, which is thought to be a degradative oxidation product of polyunsaturated acids. In this study, a genome-wide association study using 24651 single-nucleotide polymorphisms (SNPs) was performed to identify quantitative trait nucleotides (QTNs) controlling 2-heptenal content in soybean (Glycine max (L.) Merr.) seed from a natural population of 110 soybean germplasm accessions. We detected 62 significant QTNs located on 18 different chromosomes that are significantly associated with 2-heptenal content in soybean seed. Among these, 17 QTNs co-localised with QTLs previously found to be related to protein, oil and/or fatty acid content in soybean seed. We also identified some candidate genes involved in lipid metabolism. These findings further our understanding of the genetic basis of 2-heptenal content in soybean seed and the improvement of marker-assisted breeding efficiency, which will be important for breeding soybean cultivars with low 2-heptenal content.


PLoS Genetics ◽  
2008 ◽  
Vol 4 (5) ◽  
pp. e1000072 ◽  
Author(s):  
David Melzer ◽  
John R. B. Perry ◽  
Dena Hernandez ◽  
Anna-Maria Corsi ◽  
Kara Stevens ◽  
...  

2021 ◽  
Author(s):  
Duncan S Palmer ◽  
Wei Zhou ◽  
Liam Abbott ◽  
Nik Baya ◽  
Claire Churchhouse ◽  
...  

In classical statistical genetic theory, a dominance effect is defined as the deviation from a purely additive genetic effect for a biallelic variant. Dominance effects are well documented in model organisms. However, evidence in humans is limited to a handful of traits, particularly those with strong single locus effects such as hair color. We carried out the largest systematic evaluation of dominance effects on phenotypic variance in the UK Biobank. We curated and tested over 1,000 phenotypes for dominance effects through GWAS scans, identifying 175 loci at genome-wide significance correcting for multiple testing (P < 4.7 × 10-11). Power to detect non-additive loci is much lower than power to detect additive effects for complex traits: based on the relative effect sizes at genome-wide significant additive loci, we estimate a factor of 20-30 increase in sample size will be necessary to capture clear evidence of dominance similar to those currently observed for additive effects. However, these localised dominance hits do not extend to a significant aggregate contribution to phenotypic variance genome-wide. By deriving a version of LD-score regression to detect dominance effects tagged by common variation genome-wide (minor allele frequency > 0.05), we found no strong evidence of a contribution to phenotypic variance when accounting for multiple testing. Across the 267 continuous and 793 binary traits the median contribution was 5.73 × 10-4, with unbiased point estimates ranging from -0.261 to 0.131. Finally, we introduce dominance fine-mapping to explore whether the more rapid decay of dominance LD can be leveraged to find causal variants. These results provide the most comprehensive assessment of dominance trait variation in humans to date.


2020 ◽  
Author(s):  
Aditi Bhandari ◽  
Nitika Sandhu ◽  
Jérôme Bartholome ◽  
Tuong-Vi Cao-Hamadoun ◽  
Nourollah Ahmadi ◽  
...  

Abstract Background Reproductive-stage drought stress is a major impediment to rice production globally. Conventional and marker-assisted breeding strategies for developing drought tolerant rice varieties are being optimized by mining and exploiting adaptive traits, genetic diversity; identifying the alleles and understanding their interactions with genetic backgrounds for contributing to drought tolerance. Field experiments were conducted in this study to identify marker-trait associations (MTAs) involved in response to yield under reproductive-stage drought. A diverse set of 280 indica-aus accessions was phenotyped for grain yield and nine yield-related traits under normal condition and under two managed drought environments. The accessions were genotyped with 215,250 single nucleotide polymorphism markers. Results The study identified a total of 220 significant MTAs and candidate gene analysis within 200kb window centred from GWAS identified SNP peaks detected these MTAs within/ in close proximity to 47 genes, 4 earlier reported major grain yield QTLs and 8 novel QTLs for 10 traits. The significant MTAs were majorly located on chromosomes 1, 2, 5, 6, 11 and 12 and the percent phenotypic variance captured for these traits ranged from 5 to 88%. The significant positive correlation of grain yield with yield-related traits, except flowering time, observed under different environments point towards their contribution in improving rice yield under drought. Seven promising accessions were identified for use in future genomics-assisted breeding program targeting grain yield improvement under drought. Conclusion These results provide a promising insight into the complex-genetic architecture of grain yield under reproductive-stage drought under different environments. Validation of major genomic regions reported in the study can be effectively used to develop drought tolerant varieties following marker-assisted selection as well as to identify genes and understanding the associated physiological mechanisms.


2021 ◽  
Vol 53 (9) ◽  
pp. 1290-1299
Author(s):  
Nurlan Kerimov ◽  
James D. Hayhurst ◽  
Kateryna Peikova ◽  
Jonathan R. Manning ◽  
Peter Walter ◽  
...  

AbstractMany gene expression quantitative trait locus (eQTL) studies have published their summary statistics, which can be used to gain insight into complex human traits by downstream analyses, such as fine mapping and co-localization. However, technical differences between these datasets are a barrier to their widespread use. Consequently, target genes for most genome-wide association study (GWAS) signals have still not been identified. In the present study, we present the eQTL Catalogue (https://www.ebi.ac.uk/eqtl), a resource of quality-controlled, uniformly re-computed gene expression and splicing QTLs from 21 studies. We find that, for matching cell types and tissues, the eQTL effect sizes are highly reproducible between studies. Although most QTLs were shared between most bulk tissues, we identified a greater diversity of cell-type-specific QTLs from purified cell types, a subset of which also manifested as new disease co-localizations. Our summary statistics are freely available to enable the systematic interpretation of human GWAS associations across many cell types and tissues.


2019 ◽  
Vol 7 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Tianwang Wen ◽  
Baosheng Dai ◽  
Tao Wang ◽  
Xinxin Liu ◽  
Chunyuan You ◽  
...  

2020 ◽  
Vol 21 (14) ◽  
pp. 4830
Author(s):  
Wubin Wang ◽  
Bin Zhou ◽  
Jianbo He ◽  
Jinming Zhao ◽  
Cheng Liu ◽  
...  

Drought is one of the most important factors affecting plant growth and productivity. The previous results on drought tolerance (DT) genetic system in soybean indicated a complex of genes not only few ones were involved in the trait. This study is featured with a relatively thorough identification of QTL-allele/candidate-gene system using an efficient restricted two-stage multi-locus multi-allele genome-wide association study, on two comprehensive DT indicators, membership index values of relative plant weight (MPW) and height (MPH), instead of a single biological characteristic, in a large sample (564 accessions) of the Chinese cultivated soybean population (CCSP). Based on 24,694 multi-allele markers, 75 and 64 QTL with 261 and 207 alleles (2–12/locus) were detected for MPW and MPH, explaining 54.7% and 47.1% of phenotypic variance, respectively. The detected QTL-alleles were organized into a QTL-allele matrix for each indicator, indicating DT is a super-trait conferred by two (even more) QTL-allele systems of sub-traits. Each CCSP matrix was separated into landrace (LR) and released cultivar (RC) sub-matrices, which showed significant differentiation in QTL-allele constitutions, with 58 LR alleles excluded and 16 new ones emerged in RC. Using the matrices, optimal crosses with great DT transgressive recombinants were predicted. From the detected QTL, 177 candidate genes were annotated and validated with quantitative Real-time PCR, and grouped into nine categories, with ABA and stress responders as the major parts. The key point of the above results is the establishment of relatively full QTL-allele matrices composed of numerous gene functions jointly conferring DT, therefore, demonstrates the complexity of DT genetic system and potential of CCSP in DT breeding.


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