Search Results (607)

Rhizoctonia solani root rot (RSRR) is a major disease that significantly reduces soybean yields, causing substantial economic losses to global soybean production. To elucidate the genetic basis of RSRR resistance, 310 soybean germplasm accessions were evaluated using the disease severity index (DSI) following inoculation with R. solani. Among these accessions, 46.13% were susceptible, and only 2.26% exhibited high resistance. Utilizing resequencing data consisting of 738,561 Single Nucleotide Polymorphism (SNP) loci, a genome-wide association study (GWAS) was performed by integrating both general linear model (GLM) and mixed linear model (MLM) approaches, resulting in the identification of 21 SNPs significantly associated with resistance on chromosomes 3, 13, 15, 16, 17, and 18, and six candidate genes. RT-qPCR expression analysis revealed that four genes, including Glyma.03G166300, Glyma.03G168100, Glyma.13G212700, and Glyma.13G212300, were significantly upregulated in resistant genotypes after inoculation. Furthermore, Cleaved Amplified Polymorphic Sequences (CAPS) and Kompetitive Allele Specific PCR (KASP) molecular markers were successfully developed based on the RSRR-associated SNPs S3_38086892, S3_38247290, and S13_32595026, providing effective tools for marker-assisted selection (MAS). The findings strengthen our genetic knowledge concerning RSRR resistance and contribute to the molecular breeding of resistant soybean cultivars. Full article

Increasing the litter size in sheep is a primary objective in breeding programs, driving sustained interest in identifying candidate functional genes and molecular markers associated with fecundity. The known FecD mutation in the LEPR gene has been shown to regulate reproductive traits by influencing the ovulation rate of Davisdale sheep. However, the relationship between single-nucleotide polymorphisms (SNPs) in the LEPR and litter size remains unknown in Gobi short tail sheep and Sonid sheep. In this research, we found one novel variant and thirteen known variants through direct sequencing in Sonid sheep and Gobi short tail sheep and performed an association study in a large-scale population. The association analysis identified two SNPs (c.240C>T (rs159694506) and c.279C>T (rs159694508)) with significant litter size associations in Gobi short tail sheep (p < 0.01 ). In Sonid sheep, the c.240C>T (rs159694506), c.279C>T (rs159694508), g.41249772C>T (rs412130067), g.41249873A>C (rs425490800), g.41250357T>C (rs424307284), and g.41250358T>C (rs404651806) SNPs were significantly associated with litter size (p < 0.05 ). In addition, in GB sheep, the frequency of the litter-size-associated C allele at the c.240C>T (rs159694506) and c.279C>T (rs159694508) variants were significantly lower than that in Sonid sheep (SN), Mongolia sheep (MG), Ujimqin sheep (UM), Tan sheep (Tan), Hu sheep (Hu), and Small-tailed Han sheep (STH) populations. In SN sheep, the frequency of the litter-size-associated C allele at the c.240C>T (rs159694506) and c.279C>T (rs159694508) variant was significantly lower than that in the DPU. These findings provided valuable molecular markers pertinent to the fecundity of sheep, offering scientific evidence for the genetic improvement of these breeds. Full article

Camelina sativa is an oilseed crop that has shown strong promise as a biofuel feedstock. The profile of fatty acids greatly influences the oil quality; however, genetic mechanisms that determine the natural variation of fatty acid composition in camelina are not fully understood. A genome wide association study (GWAS) was performed to uncover genetic loci that may contribute to the contents of major fatty acids such as oleic and linolenic acids in camelina seed. Two approaches were taken to improve the GWAS efficiency. First, growing a diversity panel of 212 accessions in four locations and two nitrogen fertilization conditions revealed great variation in fatty acid contents in seeds. Second, using an improved reference genome, abundant markers, including 203,320 single nucleotide polymorphisms (SNPs) and 99,067 insertions/deletions (indels), were developed, which refined the population structure of the diversity panel. GWAS resulted in 118 genetic markers across 31 trait/treatment conditions. Closely linked markers were determined based on linkage decay and by comparing secondarily associated markers when highly associated ones were removed. Candidate genes were examined by comparing the pangenomes of 12 high-quality reference genomes. This study provides new resources to understand seed lipid metabolism and improve camelina oils through molecular breeding. Full article

Common vetch (Vicia sativa L.) is a globally green manure and forage crop, cultivated extensively worldwide. Its seeds serve as an important concentrated feed. Due to the late release of the reference genome, few studies were conducted to analyze the genetic mechanisms of grain yield, which hindered the progress of common vetch breeding. Marker-assisted selection (MAS) is the best and most effective way to accelerate the genetic improvement of grain yield-related traits in common vetch. In this study, we performed a genome-wide association study (GWAS) using the high-density single nucleotide polymorphism (SNP) data obtained through re-sequencing to better understand the genetic basis of grain yield-related traits. In total, six grain yield-related traits were evaluated in 172 accessions mainly sourced from China and Russia, across four environments, including branches per plant (NB), pod length (PL), number of pods per plant (NP), number of grains per pod (NG), hundred-grain weight (HGW), and grain yield (GY). Population structure analysis of the 172 accessions revealed four distinct subpopulations, exhibiting strong geographical correlation. In total, 38 loci have been identified as significantly associated with six grain yield-related traits, accounting for 13.3–31.7% of the phenotypic variances. Among them, qGY1.1 and qNG1.1, qNG2.2 and qPL2.1, qNG3.2 and qGY3.2, qNG4.1 and qPL4.1, qGY4.1 and qHGW4.1, qNG6.1 and qPL6.1, and qNB6.2 and qGY6.2 exhibit overlapping regions, suggesting that these regions are pleiotropic and should be prioritized for further research and breeding. In total, 12 candidate genes encoding auxin response factor, F-box repeat protein, gibberellin receptor, serine/threonine-protein kinase-like protein, and cellulose synthase-like protein were identified. Furthermore, we successfully developed and verified a kompetitive allele-specific PCR (KASP) marker (Kasp-NB6.2) for the number of branches. These findings provide molecular insights into grain yield-related traits in common vetch and offer valuable loci and molecular tools for MAS breeding. Full article

Sugarcane smut, caused by Sporisorium scitamineum, is a globally prevalent disease that severely impacts sugarcane yield and quality. The most cost-effective and sustainable approach to disease control is breeding for smut-resistant varieties. In this study, we conducted a genome-wide association study (GWAS) using a panel of core sugarcane parents and their derived lines to elucidate the genetic basis of smut resistance across seven different environments. We identified 68 new loci significantly associated with smut resistance across all the chromosomes. Based on functional annotations and genomic positions, 164 candidate genes were identified, many of which are related to enzymatic systems, resistance genes, transcription factors, and other pathways implicated in smut defense. Using resistance ratings and associated SNPs, we further selected ten elite parents and derivatives as potential donors for marker-assisted selection (MAS). This study provides a valuable reservoir of genetic resources for improving smut resistance in sugarcane. Full article

As the fourth-largest global food crop, the quality and functional characteristics of processed potato products are closely linked to endogenous sugar metabolism in tubers, with the trehalose–sucrose metabolism playing a key role in processing adaptability. This study analyzed 333 accessions from a tetraploid potato natural population. The trehalose and sucrose content of potato tubers at harvest was quantified using the high-performance liquid chromatography (HPLC) method. Combined with whole-genome resequencing, a genome-wide association study (GWAS) was conducted to map regulatory loci and identify candidate genes. The results showed that relative trehalose content in tubers was 20.38–24.78, while relative sucrose content was 10.32–19.50. Frequency histograms for both sugars exhibited normal distributions characteristic of quantitative traits, and a positive correlation was observed between them. GWAS for trehalose identified 111 significant SNP loci, mainly on chromosomes 10 and 12, leading to the identification of 88 candidate genes. Kyoto encyclopedia of genes and genomes analysis (KEGG) revealed that trehalose-related genes were primarily involved in pathways such as ABC transporters, tricarboxylic acid (TCA) cycle, and cysteine and methionine metabolism. Candidate genes potentially regulating tuber trehalose content included GH10, GH28, GH127, UXS, UGT, PMEI, and MYB108. For sucrose, GWAS identified 279 significant SNP loci, mainly on chromosomes 5, 6, and 12, resulting in 111 candidate genes. KEGG enrichment analysis showed that sucrose-related genes were enriched in pathways including starch and sucrose metabolism, cyanoamino acid metabolism, and phenylpropanoid biosynthesis. Candidate genes potentially regulating tuber sucrose content included GH17, GH31,GH47, GH9A4, SPP1, BGLU12, GSA1, TPS8, cwINV4, HXK, UST, MYB5, MYB14, and WRKY11. Therefore, this study provides marker loci for trehalose and sucrose metabolism research, aiming to clarify their regulatory mechanisms and support potato variety improvement and superior germplasm development. Full article

Buffaloes are a vital genetic resource for dairy production, yet advancements in improving milk production have been somewhat limited. In this study, we performed an integrated analysis of genomic sequencing data from 78 water buffaloes and their milk production traits, with a focus on 305-day milk yield (MY). Leveraging advancements in sequencing technology alongside genome-wide association study (GWAS) methods such as cBLUP, GMATs, and BayesR, we aimed to identify genetic factors that could facilitate the breeding of high-quality buffaloes. Our analysis revealed two significant SNPs associated with milk production traits. Based on these markers, four candidate genes were identified within the surrounding genomic regions. These genes showed significant enrichment in lactation-related pathways, including the prolactin signaling pathway (mitogen-activated protein kinase 10, MAPK10), IL-17 signaling pathway (MAPK10), MAPK signaling pathway (MAPK10), and adipocytokine signaling pathway (MAPK10). The identification of these candidate genes, particularly MAPK10, provides a robust theoretical basis for molecular breeding strategies aimed at enhancing milk production in buffaloes. This work paves the way for more targeted and effective breeding programs in the future. Full article

Background: In Kazakhstan, there is a notable demand for fat-tail sheep breeds in both domestic and international markets, which has led to the prioritization of certain breeds for breeding purposes. Among the various sheep breeds raised in the desert and semi-desert regions of Kazakhstan, the Kazakh fat-tailed coarse-wool sheep is particularly valued for its production of high-quality mutton. Objective: This study aimed to identify genomic regions and candidate genes associated with body conformation traits in this breed using a genome-wide association study (GWAS). Methods: A GWAS was performed on 295 Kazakh fat-tailed coarse-wool using OvineSNP50 Genotyping BeadChip (Illumina, San Diego, CA, USA). Results: After quality control, 41,912 single-nucleotide polymorphisms (SNPs) remained for analysis. Several loci showed suggestive associations (p < 1 × 10⁻⁵) with growth traits. These included s23127.1 and OAR6_56152225.1 for live weight; s08490.1 for chest width; s22731.1 for oblique length; OAR10_1168444.1 for cannon bone circumference; and s58409.1 for both rump height and withers height. Candidate genes near these loci encompassed VCAN, NEK1, NRG1, ADAM12, ERBB4, RUNX1T1, and PDGFD. Conclusion: Thus, these genetic variations have the potential to serve as candidate markers for MAS targeting body conformation traits in Kazakh fat-tailed coarse-wool sheep. Full article

Yaks (Bos grunniens) are a predominant livestock species on the Tibetan Plateau, known for their adaptability to the cold and dry climate typical of this region. This study investigates the association of two SNPs within the ATF6 gene (Chr3:9812652G>T (CM016692.1) and Chr3:9900243C>T (CM016692.1)) with key milk-quality traits in yaks. Due to the low frequency of TT homozygotes (<5%), analysis focused on major genotypes: GG vs. GT and CC vs. CT. Results from the general linear models revealed that the g.3_9812652G>T variant was significantly associated with increased levels of casein, protein, acidity, and solid-not-fat (SNF) in GT individuals (p < 0.01). No significant differences were observed for lactose, urea, citric acid, or fat. For g.3_9900243C>T, CT individuals showed higher casein, protein, SNF, and citric acid levels compared to CC (p < 0.05). These results suggest both SNPs are linked to key milk traits, especially protein, casein, and SNF. The g.3_9812652G>T variant had a stronger and more consistent effect, indicating it may play a larger role in milk composition regulation. Overall, ATF6 is a promising candidate gene for marker-assisted selection (MAS) to improve milk quality in yaks. Further studies in larger and more diverse populations are needed to confirm these findings and explore the gene’s functional role. Full article

Background: Chinese Red Steppe cattle (CRS) combine indigenous environmental resilience with moderate dairy performance, whereas Holstein cattle (HOL), despite their high milk yield, suffer reduced genetic diversity and compromised adaptation. A comparative analysis of their population genetic architecture and selection signatures can reveal valuable targets for CRS dairy improvement. Methods: We genotyped 61 CRS and 392 HOL individuals using the Illumina GGP Bovine 100K SNP array and performed stringent quality control. Population structure was assessed via principal component analysis, neighbor-joining trees, and sparse nonnegative matrix factorization. Historical effective population size (Ne) and divergence time were inferred with SMC++. Genome-wide selection scans combined Fixation Index (FST) and Cross-Population Composite Likelihood Ratio test (XP-CLR); overlapping high-confidence regions were annotated and subjected to GO and KEGG enrichment analyses. Results: CRS and HOL were clearly separated along PC1 (explaining 57.48% of variance), with CRS exhibiting high internal homogeneity and weak substructure, versus greater diversity and complex substructure in HOL. SMC++ indicated a split approximately 3500 years ago (700 generations) and a pronounced recent decline in Ne for both breeds. Joint selection mapping identified 767 candidate genes; notably, the ACSM1/2B/3/4 cluster on chromosome 25—key to butanoate metabolism—showed the strongest signal. Enrichment analyses highlighted roles for proteasome function, endoplasmic reticulum stress response, ion homeostasis, and RNA processing in regulating milk fat synthesis and protein secretion. Conclusion: This study delineates the genetic divergence and demographic history of CRS and HOL, and pinpoints core genes and pathways—particularly those governing butanoate metabolism and protein quality control—underlying dairy traits. These findings furnish molecular markers and theoretical guidance for precision breeding and sustainable utilization of Chinese Red Steppe cattle. Full article

This study aimed to identify candidate genes associated with chlorophyll content in rice via genome-wide association studies (GWAS) and to develop molecular markers for the selection of genetic resources and breeding lines exhibiting high chlorophyll content. Measurement of the Soil and Plant Analysis Development (SPAD) values, indicative of chlorophyll content and photosynthetic potential, were measured in 198 rice genetic resources across three years under consistent nitrogen conditions. Nitrogen fertilizer (as urea) was applied at a rate of 90 kg N ha⁻¹. After analyzing the multi-year SPAD data, genetic resources with the coefficient of variation (CV) value exceeding 20% were excluded, and the remaining 175 accessions were used for subsequent analyses. Population structure analysis using the principal component analysis (PCA) and phylogenetic methods confirmed clear genetic differentiation, supporting the reliability of the GWAS. A GWAS using 289,569 SNPs identified 17 significant loci, among which four quantitative trait loci (QTLs)—qSV3-1, qSV3-2, qSV6, and qSV7—explained over 20% of phenotypic variance. Analysis of their additive effects revealed distinct SPAD distributions among QTL combination groups, with accessions harboring all four QTLs exhibiting the highest values. Candidate gene analysis within ± 200 kb of lead SNPs identified Os03g079100 (OsUCL8), involved in photosynthesis, near qSV3-2. A derived cleaved amplified polymorphic sequence (dCAPS) marker was developed to differentiate alleles at this locus and validated via restriction digestion. These results provide key genetic insights into chlorophyll accumulation and offer molecular markers for breeding high-yielding rice cultivars with enhanced chlorophyll content. The results of this study are expected to contribute to the development of sustainable rice varieties by utilizing the developed markers and identified candidate genes to increase SPAD values, thereby enhancing nitrogen use efficiency, improving photosynthetic capacity, and ultimately increasing rice productivity. Full article

Molecular research for genetic variants underlying body weight (BW) provides crucial information for this important selected trait when developing productive poultry breeds, lines and crosses. We searched for molecular markers—single nucleotide polymorphisms (SNPs)—and candidate genes associated with this trait in 240 F₂ resource population Japanese quails (Coturnix japonica). This population was produced by crossing two breeds with contrasting growth phenotypes, i.e., Japanese (with lower growth) and Texas White (with higher growth). The birds were genotyped using the genotyping-by-sequencing method followed by a genome-wide association study (GWAS). Using 74,387 SNPs, GWAS resulted in 142 significant SNPs and 42 candidate genes associated with BW at the age of 1, 14, 28, 35, 42, 49 and 56 days. Hereby, 25 SNPs simultaneously associated with BW at more than one age were established that colocalized with nine prioritized candidate genes (PCGs), including ITM2B, SLC35F3, ADAM33, UNC79, LEPR, RPP14, MVK, ASTN2, and ZBTB16. Twelve PCGs were identified in the regions of two or more significant SNPs, including MARCHF6, EGFR, ADGRL3, ADAM33, NPC2, LTBP2, ZC2HC1C, SATB2, ASTN2, ZBTB16, ADAR, and LGR6. These SNPs and PCGs can serve as molecular genetic markers for the genomic selection of quails with desirable BW phenotypes to enhance growth rates and meat productivity. Full article

Red epicarp in pears is an important trait for breeding. Exploring the genes regulating pear anthocyanin synthesis and developing molecular markers associated with these traits are important for obtaining new varieties of red pears. We performed whole-genome resequencing (WGS) on 127 ‘Yuluxiang (Pyrus bretschneideri)’ × ‘Xianghongli (Pyrus communis)’ F1 populations and identified a total of 510,179 single-nucleotide polymorphism (SNP) sites in the population. In total, 1972 bins were screened to form a high-density genetic map with a total map length of 815.507 cM, covering 17 linkage groups with an average genetic distance of 0.414 cM between markers. Three red skin quantitative trait loci (QTLs), located on LG4 and LG5, that explained 18.7% of the phenotypic variance, were detected. The QTL intervals contained 1658 genes, including 94 transcription factors (TF), subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Four key candidate genes (Pspp.Chr05.01969, Pspp.Chr05.01908, Pspp.Chr05.02419, and Pspp.Chr04.01087) that may play a role in promoting pear anthocyanin synthesis were screened and identified by a quantitative polymerase chain reaction (qPCR). Overall, our study deepens our understanding of the genetics of red peel traits in pears and accelerates pear breeding. Full article

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), represents a major global threat to wheat (Triticum aestivum. L). Planting varieties with adult-plant resistance (APR) is an effective approach for long-term management of this disease. The Chinese winter wheat variety Lantian 25 exhibits moderate-to-high APR against stripe rust under field conditions. To investigate the genetic basis of APR in Lantian 25, a set of 219 F₆ recombinant inbred lines (RILs) was created from a cross between Lantian 25 (resistant parent) and Huixianhong (susceptible parent). These RILs were assessed for maximum disease severity (MDS) in Pixian of Sichuan and Qingshui of Gansu over the 2020–2021 and 2021–2022 growing seasons, resulting in data from four different environments. Genotyping was performed on these lines and their parents using the wheat Illumina 50K single-nucleotide polymorphism (SNP) arrays. Composite interval mapping (CIM) identified six quantitative trait loci (QTL), named QYr.gaas-2BS, QYr.gaas-2BL, QYr.gaas-2DS, QYr.gaas-2DL, QYr.gaas-3BS and QYr.gaas-4BL, which were consistently found across two or more environments and explained 4.8–12.0% of the phenotypic variation. Of these, QYr.gaas-2BL, QYr.gaas-2DS, and QYr.gaas-3BS overlapped with previous studies, whereas QYr.gaas-2BS, QYr.gaas-2DS, and QYr.gaas-4BL might be novel. All the resistance alleles for these QTL originated from Lantian 25. Furthermore, four kompetitive allele-specific PCR (KASP) markers, Kasp_2BS_YR (QYr.gaas-2BS), Kasp_2BL_YR (QYr.gaas-2BL), Kasp_2DS_YR (QYr.gaas-2DS) and Kasp_2DL_YR (QYr.gaas-2DL), were developed and validated in 110 wheat diverse accessions. Additionally, we identified seven candidate genes linked to stripe rust resistance, including disease resistance protein RGA2, serine/threonine-protein kinase, F-box family proteins, leucine-rich repeat family proteins, and E3 ubiquitin-protein ligases. These QTL, along with their associated KASP markers, hold promise for enhancing stripe rust resistance in wheat breeding programs. Full article

Colored wheat lines, which feature elevated anthocyanin content and associated traits, represent valuable genetic resources for enhancing the plant’s nutritional and aesthetic properties. This genome-wide association study (GWAS) utilized a set of radiation-induced mutant lines to identify genetic loci linked to agricultural and biochemical traits. The GWAS models Fixed and Random Model Circulating Probability Unification, and the Bayesian-information and Linkage-Disequilibrium Iteratively Nested Keyway were employed to increase the reliability of marker–trait associations (MTAs). In total, 35 significant MTAs were identified, and seven single-nucleotide polymorphisms (SNPs) were commonly detected by both models. To explore candidate genes, a ± 1.5-Mb window around each significant SNP was analyzed according to the estimated linkage disequilibrium decay, revealing 635 genes. Among these, several genes were annotated as transcription factors and enzymes associated with flavonoid biosynthesis and modification, including MYB, WD-repeat proteins, and UDP-glycosyltransferases. Expression profiling and RT-qPCR further supported the functional relevance of selected SNP–gene pairs, particularly for anthocyanin accumulation and seed color variation. In summary, the integration of GWAS, gene annotation, and expression data could provide valuable insights into the genetic basis of complex traits in wheat, providing data for future molecular studies and marker-assisted breeding of colored wheat mutant cultivars. Full article