scholarly journals Construction of a High-Density Genetic Map via Genome Resequencing and QTL Detection for Key Fiber Traits in Asiatic Cotton

2020 ◽  
Author(s):  
Yaohua Li ◽  
Tong Mo ◽  
Lingfang Ran ◽  
Jianyan Zeng ◽  
Chuannan Wang ◽  
...  

Abstract Background: Asiatic cotton (Gossypium arboreum, genome A2) is one of diploid cotton species producing spinnable fibers. However, few studies on the genetic mechanism of key fiber traits of Asiatic cotton have been reported. Sequencing technology advancement and the release of Asiatic cotton genome made it possible to construct a high-density SNP genetic map and further untapped QTL detection.Results: The Asiatic cotton cultivars SXY No.1 and CSLZ were crossed to develop a recombinant inbred line (RIL) population with 189 lines. Whole genome resequencing technology was employed to construct a high-density genetic map that covered 1980.17 cM with an average distance of 0.61 cM between adjacent markers. Based on fiber quality and yield component trait data from three environments, a total of 177 QTL were identified for 8 key fiber traits explaining 5.0-37.4% of the phenotypic variance. Besides, 48 stable QTL, including 15 for upper quartile length (UQL), 18 for fiber fineness (FF), 1 for immature fiber content (IFC), 4 for fiber neps count (FNC), 3 for lint percentage (LP), 7 for seed index (SI), were detected in more than one environment.Conclusions: Using a RIL population and whole genome resequencing strategy, this study presented a high-density genetic map of G. arboreum and identified 48 stable QTL for 6 key fiber traits (UQL, FF, IFC, FNC, LP, SI). Our work laid solid foundation for subsequent fine mapping of QTL for key fiber traits and cloning of controlling genes.

2018 ◽  
Vol 16 (11) ◽  
pp. 1954-1967 ◽  
Author(s):  
Gaurav Agarwal ◽  
Josh Clevenger ◽  
Manish K. Pandey ◽  
Hui Wang ◽  
Yaduru Shasidhar ◽  
...  

2018 ◽  
Vol 19 (10) ◽  
pp. 3268 ◽  
Author(s):  
Bingbing Li ◽  
Xuqiang Lu ◽  
Junling Dou ◽  
Ali Aslam ◽  
Lei Gao ◽  
...  

Watermelon (Citrullus lanatus L.) is an important horticultural crop that is grown worldwide and has a high economic value. To dissect the loci associated with important horticultural traits and to analyze the genetic and genomic information of this species, a high-density genetic map was constructed based on whole-genome resequencing (WGR), a powerful high-resolution method for single-nucleotide polymorphism (SNP) marker development, genetic map construction, and gene mapping. Resequencing of both parental lines and 126 recombinant inbred lines (RIL) resulted in the detection of 178,762 single-nucleotide polymorphism (SNP) markers in the parental lines at a sequencing depth greater than four-fold. Additionally, 2132 recombination bin markers comprising 103,029 SNP markers were mapped onto 11 linkage groups (LGs). Substantially more SNP markers were mapped to the genetic map compared with other recent studies. The total length of the linkage map was 1508.94 cM, with an average distance of 0.74 cM between adjacent bin markers. Based on this genetic map, one locus for fruit bitterness, one locus for rind color, and one locus for seed coat color with high LOD scores (58.361, 18.353, 26.852) were identified on chromosome 1, chromosome 8, and chromosome 3, respectively. These prominent loci were identified in a region of 6.16 Mb, 2.07 Mb, and 0.37 Mb, respectively. On the basis of current research, the high-density map and mapping results will provide a valuable tool for identifying candidate genes, map-based gene cloning, comparative mapping, and marker-assisted selection (MAS) in watermelon breeding.


Horticulturae ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 534
Author(s):  
Zhijiang Wu ◽  
Haiyan Deng ◽  
Guidong Liang ◽  
Xiaoying Ye ◽  
Yonghua Qin ◽  
...  

Pitaya (Hylocereus undatus) is one of the most economic fleshy fruit tree crops. This study aimed at producing a high-density linkage genetic map of pitaya based on the whole genome resequencing (WGrS) approach. For this purpose, a bi-parental F1 population of 198 individuals was generated and genotyped by WGrS. High-quality polymorphic 6434 single polymorphism nucleotide (SNP) markers were extracted and used to construct a high-density linkage map. A total of 11 linkage groups were resolved as expected in accordance with the chromosome number. The map length was 14,128.7 cM with an average SNP interval of 2.2 cM. Homology with the sequenced reference genome was described, and the physical and genetic maps were compared with collinearity analysis. This linkage map in addition to the available genomic resources will help for quantitative trait mapping, evolutionary studies and marker-assisted selection in the important Hylocereus species.


2020 ◽  
Vol 21 (3) ◽  
pp. 797 ◽  
Author(s):  
Jianfu Jiang ◽  
Xiucai Fan ◽  
Ying Zhang ◽  
Xiaoping Tang ◽  
Xiaomei Li ◽  
...  

Berry firmness is one of the most important quality traits in table grapes. The underlying molecular and genetic mechanisms for berry firmness remain unclear. We constructed a high-density genetic map based on whole-genome resequencing to identify loci associated with berry firmness. The genetic map had 19 linkage groups, including 1662 bin markers (26,039 SNPs), covering 1463.38 cM, and the average inter-marker distance was 0.88 cM. An analysis of berry firmness in the F1 population and both parents for three consecutive years revealed continuous variability in F1, with a distribution close to the normal distribution. Based on the genetic map and phenotypic data, three potentially significant quantitative trait loci (QTLs) related to berry firmness were identified by composite interval mapping. The contribution rate of each QTL ranged from 21.5% to 28.6%. We identified four candidate genes associated with grape firmness, which are related to endoglucanase, abscisic acid (ABA), and transcription factors. A qRT-PCR analysis revealed that the expression of abscisic-aldehyde oxidase-like gene (VIT_18s0041g02410) and endoglucanase 3 gene (VIT_18s0089g00210) in Muscat Hamburg was higher than in Crimson Seedless at the veraison stage, which was consistent with that of parent berry firmness. These results confirmed that VIT_18s0041g02410 and VIT_18s0089g00210 are candidate genes associated with berry firmness.


2021 ◽  
Author(s):  
Ziqi Sun ◽  
Feiyan Qi ◽  
Hua Liu ◽  
Li Qin ◽  
Jing Xu ◽  
...  

Abstract Background: Oil and protein content, as well as fatty acid composition, are important quality traits in peanut. Elucidating the genetic mechanisms underlying these traits may help researchers to obtain improved cultivars through molecular breeding techniques.Results: Whole-genome resequencing of an RIL population of 318 lines was performed to construct a high-density linkage map and identify QTLs for peanut quality. The map, containing 4561 bin markers, covered a length of 2032.39 cM with an average marker density of 0.45 cM. A total of 109 QTLs for oil content, protein content, and fatty acid compositions were mapped on the 18 peanut chromosomes. The QTL qA05.1 was detected in four different environments and exhibited a major phenotypic effect on the content of oil, proteins, and six fatty acids. The genomic region spanned by qA05.1, corresponding to a physical interval of approximately 1.50 Mb, contains two polymorphic SNPs between two parents that could cause missense mutations. The two SNP sites were employed as KASP markers and validated using lines with extremely high and low oil contents; these sites may be useful in the marker-assisted breeding of peanut varieties with high oil contents.Conclusions: A high-density genetic map with 4561 bin markers was constructed, and a major and pleiotropic QTL located on LG05 was stably detected for oil, protein and fatty acids across four different environments.


2020 ◽  
Author(s):  
Junchao Liang ◽  
Yanying Ye ◽  
Xiaowen Yan ◽  
Tingxian Yan ◽  
Yueliang Rao ◽  
...  

Abstract BackgroundImprovement in sesame (Sesamum indicum L.) drought tolerance at seedling stage is important for yield stability. Genetic approaches combing with conventional breeding is the most effective way to develop drought-tolerant cultivars. So far, only a few studies have been reported to reveal gene/ quantitative trait loci (QTL) controlling drought tolerance in sesame. To identify the genomic regions associated with drought tolerance, we constructed a high-density genetic map using a recombinant inbred line (RIL) population through whole genome re-sequencing (WGRS) technique. QTLs contributing to three seedling traits were identified under both non-stress and water stress conditions.ResultsThree drought tolerance related traits and their relative values (the ratio of value under stress to value under control condition), including seedling weight (SW), shoot length (SL) and root length (RL), were evaluated under control and PEG-induced osmotic conditions at seedling stage in a RIL population derived from cross of Zhushanbai (ZSB) and Jinhuangma (JHM). Significant variation and high broad sense heritability were observed for all traits except SW under stress condition in the population. With this population, a high-density linkage map with 1354 bin markers was constructed through WGRS strategy. Composite interval mapping analysis was performed for all the traits as well as their relative phenotypic data. A total of 34 QTLs were detected for these traits under both conditions and their relative values, and 13 stable QTLs associated with seven traits were revealed in two independent experiments, explaining on average, 4.95-16.26% of phenotypic variation for each QTL. Four of them contributed more than 10% of phenotypic variation. One region on chromosome 12 contained two major QTLs related to RL under osmotic condition and relative RL. Seven candidate genes underlying major QTLs for drought tolerance were identified according to gene descriptions and variations between parents.ConclusionThe current study reports the first QTL mapping of drought tolerance related traits through a RIL population and first QTL detection of root related trait (root length) in sesame. These findings will provide new genetic resources for molecular improvement of drought tolerance and candidate gene identification in sesame.


2020 ◽  
Author(s):  
Junchao Liang ◽  
Yanying Ye ◽  
Xiaowen Yan ◽  
Tingxian Yan ◽  
Yueliang Rao ◽  
...  

Abstract BackgroundImprovement in sesame (Sesamum indicum L.) drought tolerance at seedling stage is important for yield stability. Genetic approaches combing with conventional breeding is the most effective way to develop drought-tolerant cultivars. So far, very few studies have been reported to reveal gene/ quantitative trait loci (QTL) controlling drought tolerance in sesame. To identify the genomic regions associated with drought tolerance, we constructed a high-density genetic map using a recombinant inbred line (RIL) population through whole genome re-sequencing (WGRS) technique. QTLs contributing to three seedling traits were identified under both non-stress and water stress conditions.ResultsThree drought tolerance related traits and their relative values (the ratio of value under stress to value under control condition), including seedling weight (SW), shoot length (SL) and root length (RL), were evaluated under control and PEG-induced osmotic conditions at seedling stage in a RIL population derived from cross of Zhushanbai (ZSB) and Jinhuangma (JHM). Significant variation and high broad sense heritability were observed for all traits except SW under stress condition in the population. With this population, a high-density linkage map with 1354 bin markers was constructed through WGRS strategy. Composite interval mapping analysis was performed for all the traits as well as their relative phenotypic data. A total of 34 QTLs were detected for these three traits under both conditions and their relative values, and 13 stable QTLs associated with seven traits could be revealed in two independent experiments, explaining on average, 4.95-16.26% of phenotypic variation for each QTL. Four of them contributed more than 10% of phenotypic variation. Root length related QTLs were first identified in sesame. One region on chromosome 12 contained two major QTLs related to RL under osmotic condition and relative RL. ConclusionThe current study reports the first QTL mapping of drought tolerance related traits through a RIL population and first QTL detection of root related trait (root length) in sesame. These findings will provide new genetic resources for molecular improvement of drought tolerance and candidate gene identification in sesame.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yanlin An ◽  
Linbo Chen ◽  
Lingling Tao ◽  
Shengrui Liu ◽  
Chaoling Wei

High-quality genetic maps play important roles in QTL mapping and molecular marker-assisted breeding. Tea leaves are not only important vegetative organs but are also the organ for harvest with important economic value. However, the key genes and genetic mechanism of regulating leaf area have not been clarified. In this study, we performed whole-genome resequencing on “Jinxuan,” “Yuncha 1” and their 96 F1 hybrid offspring. From the 1.84 Tb of original sequencing data, abundant genetic variation loci were identified, including 28,144,625 SNPs and 2,780,380 indels. By integrating the markers of a previously reported genetic map, a high-density genetic map consisting of 15 linkage groups including 8,956 high-quality SNPs was constructed. The total length of the genetic map is 1,490.81 cM, which shows good collinearity with the genome. A total of 25 representative markers (potential QTLs) related to leaf area were identified, and there were genes differentially expressed in large and small leaf samples near these markers. GWAS analysis further verified the reliability of QTL mapping. Thirty-one pairs of newly developed indel markers located near these potential QTLs showed high polymorphism and had good discrimination between large and small leaf tea plant samples. Our research will provide necessary support and new insights for tea plant genetic breeding, quantitative trait mapping and yield improvement.


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