Identification of QTLs and a Candidate Gene Affecting Rice Grain Volume via High-Density Genetic Mapping
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ABSTRACT:
ORGANISM(S): Oryza sativa Japonica (common rice)
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PROVIDER: S-BSST1640 | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:BackgroundAnaerobic germination tolerance is an important trait for direct-seeded rice varieties. Understanding the genetic basis of anaerobic germination is a key for breeding direct-seeded rice varieties.ResultsIn this study, a recombinant inbred line (RIL) population derived from a cross between YZX and 02428 exhibited obvious coleoptile phenotypic differences. Mapping analysis using a high-density bin map indicated that a total of 25 loci were detected across two cropping seasons, including 10 previously detected loci and a total of 13 stable loci. Analysis of the 13 stable loci demonstrated that the more elite alleles that were pyramided in an individual, the higher the values of these traits were in the two cropping seasons. Furthermore, some anaerobic germination-tolerant recombinant inbred lines, namely G9, G10, G16, and G151, were identified. A total of 84 differentially expressed genes were obtained from the 13 stable loci via genome-wide expression analysis of the two parents at three key periods. Among them, Os06g0110200, Os07g0638300, Os07g0638400, Os09g0532900, Os09g0531701 and Os12g0539751 constitute the best candidates associated with anaerobic germination.ConclusionsBoth the anaerobic germination-tolerant recombinant inbred lines and the loci identified in this study will provide new genetic resources for improving the anaerobic germination tolerance of rice using molecular breeding strategies, as well as will broaden our understanding of the genetic control of germination tolerance under anaerobic conditions.
| S-EPMC6506967 | biostudies-literature
Project description:KEY MESSAGE:The quantitative trait loci (QTLs) for grain morphological traits were identified via nested association mapping and validated in a natural wheat population via haplotype analysis. Grain weight, one of the three most important components of crop yield, is largely determined by grain morphological traits. Dissecting the genetic bases of grain morphology could facilitate the improvement of grain weight and yield production. In this study, four wheat recombinant inbred line populations constructed by crossing the modern variety Yanzhan 1 with three semi-wild wheat varieties (i.e., Chayazheda, Yutiandaomai, and Yunnanxiaomai from Xinjiang, Tibet, and Yunnan, respectively) and one exotic accession Hussar from Great Britain were investigated for grain weight and eight morphological traits in seven environments. Eighty-eight QTLs for all measured traits were totally identified through nested association mapping utilizing 14,643 high-quality polymorphic single nucleotide polymorphism (SNP) markers generated by 90 K SNP array. Among them, 64 (72.7%) QTLs have the most favorable alleles donated by semi-wild wheat varieties. For 14 QTL clusters affecting at least two grain morphological traits, nine QTL clusters were located in similar position with known genes/QTL, and the other five were novel. Three important novel QTLs (i.e., qTGW-1B.1, qTGW-1B.2, and qTGW-1A.1) were further validated in a natural wheat population via haplotype analysis. The favorable haplotypes for these three QTLs might be used in marker-assisted selection for the improvement of wheat yield by modifying morphological traits.
| S-EPMC6791957 | biostudies-literature
Project description:BackgroundGrain chalkiness is one of important factors affected rice grain quality. It is known that chalkiness is affected by the high temperature during the seed filling period. Although a larger of QTLs for chalkiness were reported across all 12 chromosomes, only a few of the QTLs were fine mapped or cloned up to now. Here, we fine map two QTLs for chalkiness in two single-segment substitution lines (SSSLs), 11-09 with substitution segment from O. sativa and HP67-11 with substitution segment from O. glaberrima.ResultsThe grain chalkiness of SSSLs 11-09 and HP67-11 was significantly lower than that in the recipient Huajingxian 74 (HJX74) in consecutive 8 cropping seasons. The regression correlation analysis showed that percentage of chalky grain (PCG) and percentage of chalky area (PCA) were significantly and positively correlated with percentage of grain chalkiness (PGC). Two QTLs for grain chalkiness were located on two chromosomes by substitution mapping. qPGC9 was mapped on chromosome 9 with an estimated interval of 345.6 kb. qPGC11 was located on chromosome 11 and delimited to a 432.1 kb interval in the O. sativa genome and a 332.9 kb interval in the O. glaberrima genome. qPGC11 is a QTL for grain chalkiness from O. glaberrima and was mapped in a new region of chromosome 11. The effect of two QTLs was incomplete dominance. The additive effects of two QTLs on chalkiness in second cropping season (SCS) were significantly greater than that in first cropping season (FCS).ConclusionsqPGC11 is a new QTL for grain chalkiness. The two QTLs were fine mapped. The donor alleles of qPGC9 and qPGC11 were sensitive to the high temperature of FCS.
| S-EPMC8017073 | biostudies-literature
Project description:BACKGROUND:Increasing numbers of rice farmers are adopting direct-seeding methods to save on costs associated with labor and transplanting. Successful seedling establishment in flooded conditions requires rapid coleoptile growth to ensure access to oxygen near the water surface. It is important that the natural variations in coleoptile growth of submerged rice plants are identified. RESULTS:Coleoptile responses of submerged plants at the germination stage were analyzed in diverse rice accessions and recombinant inbred lines. Several genomic regions identified from a genome-wide association analysis were significantly associated with anaerobic germination, with many that corresponded to published quantitative trait locus (QTL) intervals. In the recombinant inbred line population derived from a cross between japonica and indica varieties, only one unique and strong signal explaining about 27 % of the phenotypic variation was detected. Distinct haplotypes associated with variations in coleoptile length were identified in diverse germplasm. CONCLUSIONS:We demonstrated the value of combining genome-wide association analysis and biparental QTL mapping approaches to identify chromosomal regions regulating coleoptile elongation in submerged rice plants. The significant genomic regions detected in this study are potential candidates for incorporation into elite cultivars to improve seedling survival during anaerobic germination. Future studies that map the QTLs and investigate the effects and functions of candidate genes may lead to new rice varieties that can be used in direct-seeding systems.
| S-EPMC4689725 | biostudies-other
Project description:Grain number per panicle (GNPP), determined mainly by panicle branching, is vital for rice yield. The dissection of the genetic basis underlying GNPP could help to improve rice yield. However, genetic resources, including quantitative trait loci (QTL) or genes for breeders to enhance rice GNPP, are still limited. Here, we conducted the genome-wide association study (GWAS) on the GNPP, primary branch number (PBN), and secondary branch number (SBN) of 468 rice accessions. We detected a total of 18 QTLs, including six for GNPP, six for PBN, and six for SBN, in the whole panel and the indica and japonica subpanels of 468 accessions. More importantly, qPSG1 was a common QTL for GNPP, PBN, and SBN and was demonstrated by chromosome segment substitution lines (CSSLs). Considering gene annotation, expression, and haplotype analysis, seven novel and strong GNPP-related candidate genes were mined from qPSG1. Our results provide clues to elucidate the molecular regulatory network of GNPP. The identified QTLs and candidate genes will contribute to the improvement of GNPP and rice yield via molecular marker-assisted selection (MAS) breeding and genetic engineering techniques.
| S-EPMC9658369 | biostudies-literature
Project description:Rice varieties are required to have high yield and good grain quality. Grain chalkiness and grain shape are two important traits of rice grain quality. Low chalkiness slender grains are preferred by most rice consumers. Here, we dissected two closely linked quantitative trait loci (QTLs) controlling grain chalkiness and grain shape on rice chromosome 8 by substitution mapping. Two closely linked QTLs controlling grain chalkiness and grain shape were identified using single-segment substitution lines (SSSLs). The two QTLs were then dissected on rice chromosome 8 by secondary substitution mapping. qPGC8.1 was located in an interval of 1382.6 kb and qPGC8.2 was mapped in a 2057.1 kb region. The maximum distance of the two QTLs was 4.37 Mb and the space distance of two QTL intervals was 0.72 Mb. qPGC8.1 controlled grain chalkiness and grain width. qPGC8.2 was responsible for grain chalkiness, grain length and width. The additive effects of qPGC8.1 and qPGC8.2 on grain chalkiness were not affected by higher temperature. Two closely linked QTLs qPGC8.1 and qPGC8.2 were dissected on rice chromosome 8. They controlled the phenotypes of grain chalkiness and grain shape. The two QTLs were insensitive to higher temperature.
| S-EPMC8487414 | biostudies-literature
Project description:Rice black-streaked dwarf disease, caused by rice black-streaked dwarf virus (RBSDV), is transmitted by small brown planthoppers (Laodelphax striatellus Fallén, SBPH) and causes severe yield loss in epidemic years in China and other East Asian countries. Breeding for resistance to RBSDV is a promising strategy to control the disease. We identified Tetep that showed resistance to RBSDV using a field test and artificial inoculation test. An evaluation of the resistance mechanism revealed that Tetep was resistant to RBSDV but not to SBPH. Genetic analysis showed that the resistance of Tetep to RBSDV was controlled by quantitative trait loci (QTLs). Three new QTLs for RBSDV resistance were identified in this study, i.e., qRBSDV-3, qRBSDV-10 and qRBSDV-11. The LOD scores of qRBSDV-3, qRBSDV-10 and qRBSDV-11 were 4.07, 2.24 and 2.21, accounting for 17.5%, 0.3% and 12.4% of the total phenotypic variation, respectively. All the resistance loci identified in this study were associated with virus resistance genes. The alleles for enhancing resistance on chromosomes 3 and 11 originated from Tetep, whereas the other allele on chromosome 10 originated from a susceptible parent. The identified new resistance QTLs in this study are useful resources for efficiently breeding resistant rice cultivars to RBSDV.
| S-EPMC4510485 | biostudies-other
Project description:Several key genes governing Zn homeostasis and grain zinc content (GZC) have been functionally characterized. However, the effects of these genes in diverse breeding populations have not been evaluated; thus, their availability in breeding is unclear. In this study, the effects of 65 genes related to rice zinc responses on GZC were evaluated using two panels of breeding lines, and the superior haplotypes were identified. One panel consisted of mega varieties from the International Rice Research Institute (IRRI), South Asia, and Southeast Asia (SEA), and the other panel is breeding lines/varieties from South China (SC). In addition, a multiparent advanced generation intercross (MAGIC) population, named as DC1, was also employed. Three analytical methods, single-locus mixed linear model (SL-MLM), multilocus random-SNP-effect mixed linear model (mrMLM), and haplotype-based association analysis (Hap-AA), were applied. OsIDEF1 (which explained 12.3% of the phenotypic variance) and OsZIFL7 (8.3-9.1%), OsZIP7 (18.9%), and OsIRT1 (17.9%) were identified by SL-MLM in SEA and SC, respectively, whereas no gene was significantly associated with GZC in DC1. In total, five (OsNRAMP6, OsYSL15, OsIRT1, OsIDEF1, and OsZIFL7, 7.70-15.39%), three (OsFRDL1, OsIRT1, and OsZIP7, 11.87-17.99%), and two (OsYSL7 and OsZIP7, 9.85-10.57%) genes were detected to be significantly associated with GZC in SEA, SC, and DC1 by mrMLM, respectively. Hap-AA indicated that Hap1-OsNRAMP5, Hap5-OsZIP4, Hap1-OsIRT1, Hap3-OsNRAMP6, Hap6-OsMTP1, and Hap6-OsYSL15 had the largest effects for GZC in SEA, whereas Hap3-OsOPT7, Hap4-OsIRT2, Hap4-OsZIP7, Hap5-OsIRT1, and Hap5-OsSAMS1 were the most significant in the SC population. Besides, superior alleles were also identified for the significant genes. The genes significantly associated with GZC and their superior haplotypes identified in different panels could be used in enhancing GZC through molecular breeding, which could further address the problem of Zn malnutrition among rice consumers.
| S-EPMC8381382 | biostudies-literature
Project description:BACKGROUND:High yielding rice varieties are usually low in grain iron (Fe) and zinc (Zn) content. These two micronutrients are involved in many enzymatic activities, lack of which cause many disorders in human body. Bio-fortification is a cheaper and easier way to improve the content of these nutrients in rice grain. RESULTS:A population panel was prepared representing all the phenotypic classes for grain Fe-Zn content from 485 germplasm lines. The panel was studied for genetic diversity, population structure and association mapping of grain Fe-Zn content in the milled rice. The population showed linkage disequilibrium showing deviation of Hardy-Weinberg's expectation for Fe-Zn content in rice. Population structure at K?=?3 categorized the panel population into distinct sub-populations corroborating with their grain Fe-Zn content. STRUCTURE analysis revealed a common primary ancestor for each sub-population. Novel quantitative trait loci (QTLs) namely qFe3.3 and qFe7.3 for grain Fe and qZn2.2, qZn8.3 and qZn12.3 for Zn content were detected using association mapping. Four QTLs, namely qFe3.3, qFe7.3, qFe8.1 and qFe12.2 for grain Fe content were detected to be co-localized with qZn3.1, qZn7, qZn8.3 and qZn12.3 QTLs controlling grain Zn content, respectively. Additionally, some Fe-Zn controlling QTLs were co-localized with the yield component QTLs, qTBGW, OsSPL14 and qPN. The QTLs qFe1.1, qFe3.1, qFe5.1, qFe7.1, qFe8.1, qZn6, qZn7 and gRMm9-1 for grain Fe-Zn content reported in earlier studies were validated in this study. CONCLUSION:Novel QTLs, qFe3.3 and qFe7.3 for grain Fe and qZn2.2, qZn8.3 and qZn12.3 for Zn content were detected for these two traits. Four Fe-Zn controlling QTLs and few yield component QTLs were detected to be co-localized. The QTLs, qFe1.1, qFe3.1, qFe5.1, qFe7.1, qFe8.1, qFe3.3, qFe7.3, qZn6, qZn7, qZn2.2, qZn8.3 and qZn12.3 will be useful for biofortification of the micronutrients. Simultaneous enhancement of Fe-Zn content may be possible with yield component traits in rice.
| S-EPMC7001215 | biostudies-literature
Project description:BackgroundThe Northeast Plain of China, which is an important region for the production of high grain quality rice in China. However, the grain quality of the rice produced varies across this region, even for the same cultivar.ObjectiveIn order to explore the meteorological factors that have the greatest influence on quality and the transcriptional level differences between different cultivars and different locations at grain filling stage.MethodsWe grew eight rice cultivars in three locations in Northeast China during two growing seasons (2017 and 2018). We recorded meteorological conditions, including air temperature, air temperature range, and photosynthetically active radiation (PAR) during the grain-filling stage of each cultivar, and analyzed the grain quality of those eight cultivars.ResultsAcross all eight cultivars, meteorological factors had a stronger effect on eating quality than genotype, while genotype had a stronger effect on milling quality. Of the three environmental factors assessed, PAR was significantly correlated with the most grain quality traits. Using RNA-sequencing analysis, we identified 573 environment-specific DEGs (Differentially Expressed Genes), and 119 genotype-specific DEGs; 11 DEGs were responsive to genotype × environment interactions. These DEGs were involved in many key metabolic processes.ConclusionOur results indicated that interactions among environmental factors, especially PAR, affected rice quality in Northeast China. Further analyses of the DEGs identified herein may provide useful information for future breeding programs aiming to develop high grain quality rice varieties suitable for cultivation across Northeast China.
| S-EPMC8292277 | biostudies-literature