Search Results (129)

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is the only extant freshwater cetacean species inhabiting the Yangtze River in China. Facing significant threats from habitat degradation and human activities, this critically endangered species requires urgent conservation efforts. A thorough understanding of its genetic diversity is fundamental for informing effective conservation strategies. To address the need for stable and reliable molecular markers, this study aimed to develop and validate a set of highly polymorphic single nucleotide polymorphism (SNP) markers. Candidate SNPs were initially identified based on chromosome-level genome and whole-genome resequencing data, yielding a total of 1070 candidate loci. Following the principle of even distribution across chromosomes, 50 SNPs were randomly selected for Sanger sequencing validation, from which 35 polymorphic SNPs were preliminarily confirmed. These 35 SNPs were subsequently genotyped using the Kompetitive allele-specific PCR (KASP) assay, which successfully validated 19 highly polymorphic markers. Genetic diversity analysis using these SNPs successfully captured moderate-to-high polymorphism in the Poyang Lake population, demonstrating the capability of these markers in detecting genetic variation. The SNP markers developed in this study show promising applicability for genetic diversity assessment in the Yangtze finless porpoise. Further validation across broader geographic and demographic samples will be essential to confirm their potential efficiency for detecting spatial heterogeneity and informing region-wide management strategies. Full article

Improving wheat processing quality is a crucial objective in modern wheat breeding. Among various quality parameters, grain protein content (GPC) and wet gluten content (WGC) significantly influence the end-use quality of flour. These traits are controlled by multiple minor effect genes and highly influenced by environmental factors. Identifying stable and major-effect genetic loci and developing breeder-friendly molecular markers are of great significance for breeding high-quality wheat varieties. In this study, we evaluated the GPC and WGC of 310 diverse wheat varieties, mainly from China and Europe, across four environments. Genotyping was performed using the wheat 100K SNP chip, and genome-wide association analysis (GWAS) was employed to identify stable loci with substantial effects. In total, four loci for GPC were identified on chromosomes 1A, 3A, 3B, and 4B, with explained phenotypic variation (PVE) ranging from 6.0 to 8.4%. In addition, three loci for WGC were identified on chromosomes 4B, 5A, and 5D, which explained 7.0–10.0% of the PVE. Among these, three loci coincided with known genes or quantitative trait loci (QTL), whereas QGPC.zaas-3AL, QGPC.zaas-4BL, QWGC.zaas-4BL, and QWGC.zaas-5A were potentially novel. Seven candidate genes were involved in various biological pathways, including growth, development, and signal transduction. Furthermore, five kompetitive allele specific PCR (KASP) markers were developed and validated in a natural population. The newly identified loci and validated KASP markers can be utilized for quality improvement. This research provides valuable germplasm, novel loci, and validated markers for high-quality wheat breeding. Full article

Wheat (Triticum aestivum L.) is one of the most important staple crops in the world. Iron (Fe) plays a vital role in the growth and development of wheat as an essential nutrient. Meanwhile, Fe is closely associated with human health, as Fe deficiency anemia can cause fatigue, weakness, heart problems, and so on. In this study, quantitative trait loci (QTLs) for grain Fe content (GFeC) were detected in two populations: a recombinant inbred line (RIL) population with 175 lines derived from a cross between Avocet and Huites (AH population) genotyped with diversity array technology (DArT) and a natural population of 243 varieties (CH population) genotyped by using the 660K single-nucleotide polymorphism (SNP). Three stable QTLs (QGFe.haust-AH-5B, QGFe.haust-AH-6A, and QGFe.haust-AH-7A.2) were identified through QTL mapping with phenotypic variations of 11.55–13.63%, 3.58–9.89%, and 4.81–11.12% in the AH population in four environments. Genetic effects of QGFe.haust-AH-5B, QGFe.haust-AH-6A, and QGFe.haust-AH-7A.2 were shown to significantly increase GFeC by 8.11%, 14.05%, and 5.25%, respectively. One hundred and thirty-three significant SNPs were identified (p < 0.001) through a genome-wide association study (GWAS) for GFeC on chromosomes 1B, 2B, 3A, 3B, 5D, and 7A with phenotypic variations of 5.26–9.88% in the CH population. A novel locus was co-located within the physical interval 689.86 Mb-690.01 Mb in five environments through QTL mapping and GWAS, with one high-confidence gene, TraesCS7A02G499500, which was temporarily designated as TaqFe-7A, involved in GFeC regulation. A Kompetitive allele-specific PCR, KAFe-7A-2, was developed, which was validated in 181 natural populations. Genetic effect analysis revealed that favorable haplotype AA significantly increased GFeC by 4.64% compared to an unfavorable haplotype (p < 0.05). Therefore, this study provides the theoretical basis for cloning the GFeC gene and nutritional fortification breeding. Full article

Gray mold, caused by Botrytis cinerea, is a devastating disease of strawberry, with petal abscission rate (PAR) being a critical disease-avoidance trait. Rapid petal abscission removes a key infection site for the pathogen, thereby reducing disease incidence. To dissect the genetic basis of PAR, a segregating F₁ population was constructed from a cross between ‘Benihoppe’ (rapid abscission) and ‘Sweet Charlie’ (slow abscission). Utilizing BSR-Seq analysis of extreme bulks, five high-confidence quantitative trait loci (QTLs) were identified on chromosomes Fvb2-2, Fvb4-4, and Fvb6-3. These QTLs encompassed 672 candidate genes, with enrichment in “Plant hormone signal transduction” pathway. Integrated analysis of gene expression and SNPs identified 16 candidate genes, including those involved in flowering time (e.g., ELF3, HUA2 and AGL62) and plant hormone (e.g., ANT, RTE (ethylene), NDL2, FPF1 (auxin), and CYP707A7, ABF2 (abscisic acid) signaling, as well as calcium transport (ACA1, ECA3). Fourteen Kompetitive Allele-Specific PCR (KASP) markers were developed from candidate genes, with four markers showing significant correlations with PAR. This study provides the first genetic mapping of PAR in strawberry, revealing candidate genes and molecular markers that will facilitate the breeding of cultivars with improved gray mold resistance through enhanced petal abscission. Full article

Hypoxia is a critical environmental stressor in aquaculture, significantly affecting the survival and growth performance of cultured fish. To explore the genetic basis of hypoxia tolerance in grass carp (Ctenopharyngodon idella), we integrated genome-wide association analysis (GWAS) and multi-tissue transcriptome profiling. A total of 2000 grass carp were subjected to hypoxic stress, from which the 150 most hypoxia-intolerant (HI) and 150 most hypoxia-tolerant (HT) individuals were selected based on the time to loss of equilibrium (LOE). GWAS using 3,730,919 SNPs and 851,595 InDels identified 21 SNPs and 6 InDels associated with hypoxia tolerance. Two SNPs on chromosomes 10 and 13 reached genome-wide significance, accounting for 2.7% and 4.8% of the phenotypic variance explained (PVE), respectively. Validation of identified SNPs was performed using kompetitive allele-specific PCR (KASP) analysis. Candidate genes within ±50 kb of these variants were enriched in steroid biosynthesis, insulin signaling, and glycosphingolipid biosynthesis pathways. Transcriptomic analysis of six tissues (brain, gill, intestine, kidney, liver, and spleen) revealed 1620, 1221, 796, 246, 210, and 58 differentially expressed genes (DEGs) in the HT group compared to the HI group, respectively. DEGs in the brain were primarily enriched in steroid metabolic processes and angiogenesis regulation, while those in kidney and spleen DEGs were associated with oxygen transport and erythrocyte development. Integrated analysis of GWAS and transcriptome data identified 16 shared genes, including usf1 and trpv4. These findings reveal key genomic loci and molecular pathways underlying hypoxia tolerance in grass carp, providing valuable markers for future selective breeding programs. Full article

The Pheophorbide a oxygenase (PaO) is a key enzyme in chlorophyll degradation and plays an important role in plant senescence. However, the PaO gene’s function in sorghum remains underexplored. In this study, we identified five SbPaO gene family members in the sorghum genome through bioinformatics analysis. Analyses of gene structure, phylogeny, and collinearity revealed high conservation of this gene family among grass crops, suggesting similar functions. Subcellular localization and protein network predictions indicated that SbPaOs may participate in chlorophyll catabolism and regulate leaf senescence. Expression pattern analysis showed that SbPaO1, SbPaO3, SbPaO4, and SbPaO5 were highly expressed in leaves and significantly upregulated during senescence. Haplotype analysis found three SbPaO genes significantly linked to thousand-grain weight (TGW); superior haplotypes SbPaO1-hap4, SbPaO3-hap5, and SbPaO4-hap4 notably increased this trait. Single-gene improvements increased TGW by 10.57–17.20%, dual-gene aggregation by 18.78–24.75%, and three-gene aggregation by 29.09%. The study also developed Kompetitive Allele-Specific PCR (KASP) markers that identify superior haplotypes with 100% accuracy. In summary, this study’s results provide a theoretical basis and genetic resources for further exploration of haplotype pyramiding strategies to breed new high-yielding sorghum varieties and delineate a clear research direction for subsequent functional validation and breeding practices. Full article

Lobed leaves play a critical role in enhancing the productivity of sprawling crops like zucchini by improving light capture and boosting photosynthesis. However, the genetic basis in zucchini remains largely unknown. Here, we developed an F₂ population from a cross between the entire-leaf cultivar ‘LR’ and the deeply lobed cultivar ‘Xi’. Genetic analysis showed that the non-lobed trait is dominant, with the F₂ segregation ratios (~9 entire:6 shallowly lobed:1 deeply lobed) indicating digenic inheritance. Using bulked segregant analysis sequencing (BSA-seq) and kompetitive allele-specific PCR (KASP) marker analysis, we identified a major effect locus at a 79.8 kb interval on chromosome 10. Within in this interval, gene expression profiling and annotation indicated CpARF6, encoding an auxin response factor, to be the prime candidate gene. Sequencing analysis revealed five nonsynonymous mutations in this gene, including a critical serine-to-leucine substitution at position 335 within the auxin response domain, which is likely a loss function mutation. Our findings establish CpARF6 as a critical regulator of lobed leaf formation in zucchini, providing valuable insights for both leaf development studies and zucchini breeding. Full article

Leaf rust, a devastating fungal disease caused by Puccinia triticina (Pt), severely impacts wheat quality and yield. Identifying genetic loci for wheat leaf rust resistance, developing molecular markers, and breeding resistant varieties is the most environmentally friendly and economical strategy for disease control. This study utilized a recombinant inbred line (RIL) population of Doumai and Shi4185, combined with the wheat 90 K single nucleotide polymorphisms (SNPs) chip data and maximum disease severity (MDS) of leaf rust from four environments, to identify adult plant resistance (APR) loci through linkage mapping. Additionally, kompetitive allele-specific PCR (KASP) markers suitable for breeding were developed, and genetic effects were validated in a natural population. In this study, 5 quantitative trait loci (QTL) on chromosomes 1B (2), 2A and 7B (2) were identified through inclusive composite interval mapping, and named as QLr.lfnu-1BL1, QLr.lfnu-1BL2, QLr.lfnu-2AL, QLr.lfnu-7BL1 and QLr.lfnu-7BL2, respectively, explaining 4.54–8.91% of the phenotypic variances. The resistance alleles of QLr.lfnu-1BL1 and QLr.lfnu-1BL2 originated from Doumai, while the resistance alleles of QLr.lfnu-2AL, QLr.lfnu-7BL1 and QLr.lfnu-7BL2 came from Shi4185. Among these, QLr.lfnu-1BL2, QLr.lfnu-7BL1 and QLr.lfnu-7BL2 overlapped with previously reported loci, whereas QLr.lfnu-1BL1 and QLr.lfnu-2AL are likely to be novel. Two KASP markers, QLr.lfnu-2AL and QLr.lfnu-7BL, were significantly associated with leaf rust resistance in a diverse panel of 150 wheat varieties mainly from China. Totally, 34 potential candidate genes encoded the NLR proteins, receptor-like kinases, signaling kinases and transcription factors were selected as candidate genes for the resistance loci. These findings will provide stable QTL, available breeding KASP markers and candidate genes, and will accelerate the progresses of wheat leaf rust resistance improvement through marker-assisted selection breeding. Full article

Bacterial wilt, caused by Ralstonia solanacearum, is a major constraint to tomato production globally. To uncover resistance loci and develop efficient molecular tools for breeding, we conducted disease phenotyping over two growing seasons, which revealed consistent variation in resistance and moderate broad-sense heritability (H² = 0.22–0.28), suggesting a genetic basis. A genome-wide association study (GWAS) was performed on a diverse panel of 267 tomato accessions, evaluated against two R. solanacearum strains. A major resistance locus was identified on chromosome 12, with the strongest association observed at SNP S12_2992992, located within a gene encoding a leucine-rich repeat (LRR) receptor-like protein. Haplotype analysis indicated that the resistance-associated allele is relatively rare (~13.5%) in the population, underscoring its potential value in breeding programs. Functional validation in an F₂ population derived from a cross between the susceptible ‘Seedathip6’ and the resistant ‘Hawaii 7996’ confirmed that the TT genotype at S12_2992992 was significantly associated with enhanced resistance. A Kompetitive Allele Specific PCR (KASP) marker was developed for this SNP, facilitating cost-effective and high-throughput selection. Collectively, these findings establish S12_2992992 as a robust and functionally informative marker, offering a valuable tool for accelerating bacterial wilt resistance breeding in tomato through marker-assisted selection. Full article

Drought severely threatens wheat production. Under drought conditions, root system architecture (DRSA)-related traits in common wheat significantly affect wheat production. In China, Zhoumai16 is a high-yield winter wheat variety in the Huang-Huai wheat region. It is suitable for high-fertilizer and high-water cultivation and has moderate drought tolerance. DK171 is a newly developed high-yield and stress-tolerant variety, with higher drought tolerance. Thus, identifying genetic loci associated with DRSA-related traits from DK171 and developing available molecular markers are of great importance for enhancing wheat stress tolerance breeding. In this study, DRSA-related traits, including the total root dry weight (DDRW), total root length (DTRL), total root area (DTRA), and the number of root tips (DNRT) under drought stress, were assessed using the hydroponic system in Zhoumai16/DK171 recombinant inbred lines (RIL) population. A total of five quantitative trait loci (QTL) for DRSA-related traits were identified, e.g., QDDRW.daas-1BL, QDTRS.daas-4AL, QDNRT.daas-4DS, QDTRL.daas-3AL, and QDDRW.daas-5D, and explained 6.1% to 18.9% of the phenotypic variances, respectively. Among these, QDTRS.daas-4AL and QDTRL.daas-3AL were consistent with previous reports, whereas the QDDRW.daas-1BL, QDNRT.daas-4DS, and QDDRW.daas-5D are novel. The favorable alleles of QDTRS.daas-4AL and QDNRT.daas-4DS were inherited from Zhoumai16, whereas the favorable alleles for QDDRW.daas-1BL, QDTRL.daas-3AL, and QDDRW.daas-5D were contributed by DK171. Furthermore, five kompetitive allele-specific PCR (KASP) markers, Kasp_1BL_DTRS (QDDRW.daas-1BL), Kasp_3AL_DTRS (QDTRL.daas-3AL), Kasp_4A_DTRS (QDTRA.daas-4A), Kasp_5D_DDRW (QDDRW.daas-5D), and Kasp_4D_DNRT (QDNRT.daas-4D), were developed and validated in a diverse panel with 108 wheat varieties mainly from China. Additionally, eight candidate genes related to plant hormone regulation, ABC transporters, and calcium-dependent lipid-binding domain proteins were identified. This study offers new loci, candidate genes, and available KASP markers for wheat drought tolerance breeding and facilitating progress in developing drought-tolerant wheat cultivars. Full article

Background: High-temperature stress is one of the major abiotic stresses limiting cotton production. Identifying genetic loci and genes for heat tolerance is crucial for breeding heat-tolerant varieties. Methods: Given the complexity of heat tolerance phenotypes in cotton, this study, which focused on resource materials, identified an A/C SNP mutation at position 5486185 on chromosome D06 within the heat tolerance interval through genome-wide association studies (GWAS) of natural Gossypium hirsutum populations. Results: A total of 308 resource materials were identified and evaluated for their heat tolerance phenotypes over two years of field research. Kompetitive allele-specific PCR (KASP) molecular markers were developed on the basis of the D06-5486185 SNP to characterize the heat tolerance phenotypes of these 308 resource materials. Genotyping for heat tolerance-related traits and agronomic traits was also performed. Materials with the C/C haplotype at position D06-5486185 presented increased heat tolerance (higher pollen viability (PV), leaf area (LA), chlorophyll (Chl) and number of bolls on the third fruit branch (FB3) and a lower number of dry buds (DBs) and drop rate (DR)) without negatively impacting key yield traits. This locus is located in the intergenic region of two adjacent bZIP transcription factor genes (GH_D06G0408 and GH_D06G0409). Expression analysis revealed that the expression levels of these two genes were significantly greater in heat-tolerant accessions (C/C type) than in sensitive accessions and that their expression levels were significantly correlated with multiple heat-tolerant phenotypes. Conclusions: In summary, this study developed a Kompetitive Allele Specific PCR (KASP) marker associated with heat tolerance in G. hirsutum and identified two key heat tolerance candidate genes. These results provide an efficient marker selection tool and important genetic resources for the molecular breeding of heat-tolerant G. hirsutum, laying an important foundation for further establishing a molecular marker-assisted breeding system for heat tolerance in G. hirsutum. Full article

GADD45 (growth arrest and DNA damage inducible 45) is a crucial signaling regulator in cells and plays an important role in various biological processes, including cellular stress response, cell cycle control, DNA damage repair, apoptosis, and tumor suppression. Our previous studies identified GADD45b as a candidate gene associated with resistance to largemouth bass ranavirus (LMBV) infection in largemouth bass (Micropterus salmoides). In the present study, the upstream intergenic polymorphisms of GADD45b were investigated to explore their association with resistance/susceptibility to LMBV. We employed the kompetitive allele specific PCR (KASP) assay to genotype 118 resistant individuals and 122 susceptible individuals following LMBV infection. The results revealed that SNP38943374 C>A and SNP38943495 G>A were significantly associated with LMBV resistance/susceptibility (p < 0.01). Individuals with the CC genotype of SNP38943374 and the GG genotype of SNP38943495 were more prevalent in resistant groups and have advantages in survival time after LMBV infection. Linkage disequilibrium analysis indicated strong linkage among these two loci. The distinct dynamic expression patterns of GADD45b in different genotypes following LMBV infection suggest its functional role in viral infection. Additionally, dynamic expression levels of immune-related genes (IFN-γ, TNF-α, and IL-10) also varied among different genotypes. These results demonstrated that the two SNPs in GADD45b could be used as candidate markers for further investigation of selective breeding of resistant largemouth bass to LMBV. Full article

Faba bean rust is one of the major threats to the cultivation of faba beans worldwide. Three genes for rust resistance (Uvf-1, Uvf-2 and Uvf-3) and fifteen marker-trait associations have been identified so far. This study examines the genetic basis of rust resistance derived from BPL-261, an accessions that exhibits low infection frequency and a long latency period. We constructed a genetic map based on a RIL6 population derived from the BPL-261/Vf-274 cross, which consists of 91 individuals. Subsequent generations were used to evaluate rust resistance in Lattakia (Syria), Kafr El-Sheikh (Egypt) and Córdoba (Spain). A total of six QTLs for resistance were detected on chromosomes II, III, IV and V. Comparative analyses suggest that the QTL located on chromosome V is likely to be associated with Uvf-3. The QTL on chromosome III is close to Uvf-2 but it seems to be a different QTL since the confidence intervals do not overlap. Finally, the other QTLs constitute additional sources of rust resistance in faba beans. Functional analysis of the candidate genes within the confidence intervals suggests the hypothetical involvement of various resistance mechanisms, with salicylic acid playing a significant role but it should be confirmed with further studies. Our results advance understanding of rust resistance in faba bean. Markers identified in this study should be used to develop kompetitive allele-specific PCR (KASP) assays, after their utility has been confirmed in different genetic backgrounds. This will contribute to the development of durable rust-resistant faba bean cultivars. Full article

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

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