Putative Candidate Genes Research Articles

Unique regulatory network of dragon fruit simultaneously mitigates the effect of vanadium pollutant and environmental factors.

Under changing climatic conditions, plants are simultaneously facing conflicting stresses in nature. Plants can sense different stresses, induce systematic ROS signals, and regulate transcriptomic, hormonal, and stomatal responses. We performed transcriptome analysis to reveal the integrative stress response regulatory mechanism underlying heavy metal stress alone or in combination with heat and drought conditions in pitaya (dragon fruit). A total of 70 genes were identified from 31,130 transcripts with conserved differential expression. Furthermore, weighted gene co-expression network analysis (WGCNA) identified trait-associated modules. By integrating information from three modules and protein-protein interaction (PPI) networks, we identified 10 interconnected genes associated with the multifaceted defense mechanism employed by pitaya against co-occurring stresses. To further confirm the reliability of the results, we performed a comparative analysis of 350 genes identified by three trait modules and 70 conserved genes exhibiting their dynamic expression under all treatments. Differential expression pattern of genes and comparative analysis, have proven instrumental in identifying ten putative structural genes. These ten genes were annotated as PLAT/LH2, CAT, MLP, HSP, PB1, PLA, NAC, HMA, and CER1 transcription factors involved in antioxidant activity, defense response, MAPK signaling, detoxification of metals and regulating the crosstalk between the complex pathways. Predictive analysis of putative candidate genes, potentially governing single, double, and multifactorial stress response, by several signaling systems and molecular patterns. These findings represent a valuable resource for pitaya breeding programs, offering the potential to develop resilient "super pitaya" plants.

Fine mapping and identification of a Fusarium wilt resistance gene FwS1 in pea.

A Fusarium wilt resistance gene FwS1 on pea chromosome 6 was identified and mapped to a 91.4kb region by a comprehensive genomic-based approach, and the gene Psat6g003960 harboring NB-ARC domain was identified as the putative candidate gene. Pea Fusarium wilt, incited by Fusarium oxysporum f. sp. pisi (Fop), has always been a devastating disease that causes severe yield losses and economic damage in pea-growing regions worldwide. The utilization of pea cultivars carrying resistance gene is the most efficient approach for managing this disease. In order to finely map resistance gene, F2 populations were established through the cross between Shijiadacaiwan 1 (resistant) and Y4 (susceptible). The resistance genetic analysis indicated that the Fop resistance in Shijiadacaiwan 1 was governed by a single dominant gene, named FwS1. Based on the bulked segregant analysis sequencing analyses, the gene FwS1 was initially detected on chromosome 6 (i.e., linking group II, chr6LG2), and subsequent linkage mapping with 589 F2 individuals fine-mapped the gene FwS1 into a 91.4kb region. The further functional annotation and haplotype analysis confirmed that the gene Psat6g003960, characterized by a NB-ARC (nucleotide-binding adaptor shared by APAF-1, R proteins, and CED-4) domain, was considered as the most promising candidate gene. The encoding amino acids were altered by a "T/C" single-nucleotide polymorphism (SNP) in the first exon of the Psat6g003960, and based on this SNP locus, the molecular marker A016180 was determined to be a diagnostic marker for FwS1 by validating its specificity in both pea accessions and genetic populations with different genetic backgrounds. The FwS1 with diagnostic KASP marker A016180 could facilitate marker-assisted selection in resistance pea breeding in pea. In addition, a comparison of the candidate gene Psat6g003960 in 74SN3B and SJ1 revealed the same sequences. This finding indicated that 74SN3B carried the candidate gene for FwS1, suggesting that FwS1 and Fwf may be closely linked or an identical resistant gene against Fusarium wilt.

Determination of genomic regions associated with early storage root formation and bulking in cassava.

Early cassava storage root formation and bulking is a medium of escape that farmers and processors tend to adopt in cases of abiotic and biotic stresses like drought, flood, and destruction by domestic animals. In this study, 220 cassava genotypes from the International Institute of Tropical Agriculture (IITA), National Root Crops Research Institute (NRCRI), International Center for Tropical Agriculture (CIAT), local farmers (from farmer's field), and NextGen project were evaluated in three locations (Umudike, Benue, and Ikenne). The trials were laid out using a split plot in a randomized incomplete block design (alpha lattice) with two replications in 2 years. The storage roots for each plant genotype were sampled or harvested at 3, 6, 9, and 12 month after planting (MAP). All data collected were analyzed using the R-statistical package. The result showed moderate to high heritability among the traits, and there were significant differences (p< 0.05) among the performances of the genotypes. The genome-wide association mapping using the BLINK model detected 45 single-nucleotide polymorphism (SNP) markers significantly associated with the four early storage root bulking and formation traits on Chromosomes 1, 2, 3, 4, 5, 6, 8, 9, 10, 13, 14, 17, and 18.A total of 199 putative candidate genes were found to be directly linked to early storage root bulking and formation. The functions of these candidate genes were further characterized to regulate i) phytohormone biosynthesis, ii) cellular growth and development, and iii) biosynthesis of secondary metabolites for accumulation of starch and defense. Genome-wide association study (GWAS) also revealed the presence of four pleiotropic SNPs, which control starch content, dry matter content, dry yield, and bulking and formation index. The information on the GWAS could be used to develop improved cassava cultivars by breeders. Five genotypes (W940006, NR090146, TMS982123, TMS13F1060P0014, and NR010161) were selected as the best early storage root bulking and formation genotypes across the plant age. These selected cultivars should be used as sources of early storage root bulking and formation in future breeding programs.

Transcriptomics of developing grains reveals putative candidate genes for grain zinc and iron in bread wheat cultivar Zincol-2016

A high grain zinc wheat cultivar, Zincol-2016, was released in Pakistan to mitigate mineral malnutrition. Here, we used RNAseq based approach to reveal transcriptional landscape of its developing grains, and to identify genetic variants in zinc (Zn) and iron (Fe) homeostasis genes. Differential gene expression analysis identified 8370 differentially expressed genes (DEGs) over the course of grain filling. The profiling of 265 Fe/Zn homeostasis genes revealed the homeologs of TaNAS9, TaFER1, TaNAAT2, TaDMAS, TaZIFL5-A, TaZIFL5-D, TaZIP14-B, TaNRAMP3, TaVIT1, TaPRI2-D, TabZIPF1-7B, TabZIPF1-7D, TabZIPF2-5A, and TabZIPF2-5B had increased expression in Zincol-2016 relative to other cultivars from expVIP database. The variant calling identified 358 SNPs and 34 InDels in the Fe/Zn homeostasis genes. Two of those SNPs in TaZIP14-B (TraesCS3B02G140400), and TaNAAT2-B (TraesCS1B02G300600), were associated with grain zinc and iron concentrations (GZnC and GFeC) in a diverse panel of 145 wheat cultivars. The Zincol-type alleles of both genes significantly increased GZnC and GFeC by 7.3–8.6% and 5.9–6.3%, respectively. In addition, 8 SNPs causing missense mutation and 2 InDels causing frameshift mutation were found unique to Zincol. The present study forms a basis for understanding the genetic basis of high GZnC and GFeC in Zincol-2016 and can help efforts to biofortify other wheat varieties.

Detecting the genetic variants associated with key culinary traits in Dioscorea alata

Quality attributes play a pivotal role in determining consumers’ acceptance and market value of food crops. Dioscorea alata is a major yam species for food security in tropical areas, but our understanding of the genetic factors underlying tuber culinary traits is limited. This study aimed at elucidating the genetic basis of key culinary attributes, including apparent dry matter content (DM), cooking time, boiled yam hardness, and moldability, through genome-wide association studies (GWAS). Phenotypic assessment revealed notable variations among the D. alata genotypes and significant correlations among the quality traits. The GWAS identified 25 significant associations distributed across 14 chromosomes. A total of 12, 1, 6, 6 single nucleotide polymorphisms were detected for cooking time, moldability, hardness and DM. Allele segregation analysis of the identified loci highlighted favorable alleles for short cooking time, good moldability, high hardness and DM content. Within a set of 42 putative candidate genes, we identified genes differentially expressed in tubers of genotypes with contrasting quality attributes. Our study offers valuable insights into the links between these key culinary traits and the underlying genetic basis in D. alata. These findings have practical implications for breeding programs aimed at enhancing the quality attributes of greater yam.

A systems genetic analysis identifies putative mechanisms and candidate genes regulating vessel traits in poplar wood.

Wood is the water conducting tissue of tree stems. Like most angiosperm trees, poplar wood contains water-conducting vessel elements whose functional properties affect water transport and growth rates, as well as susceptibility to embolism and hydraulic failure during water stress and drought. Here we used a unique hybrid poplar pedigree carrying genomically characterized chromosomal insertions and deletions to undertake a systems genomics analysis of vessel traits. We assayed gene expression in wood forming tissues from clonal replicates of genotypes covering dosage quantitative trait loci with insertions and deletions, genotypes with extreme vessel trait phenotypes, and control genotypes. A gene co-expression analysis was used to assign genes to modules, which were then used in integrative analyses to identify modules associated with traits, to identify putative molecular and cellular processes associated with each module, and finally to identify candidate genes using multiple criteria including dosage responsiveness. These analyses identified known processes associated with vessel traits including stress response, abscisic acid and cell wall biosynthesis, and in addition identified previously unexplored processes including cell cycle and protein ubiquitination. We discuss our findings relative to component processes contributing to vessel trait variation including signaling, cell cycle, cell expansion, and cell differentiation.

Transcriptome-wide association mapping provides insights into the genetic basis and candidate genes governing flowering, maturity and seed weight in rice bean (Vigna umbellata)

BackgroundRice bean (Vigna umbellata), an underrated legume, adapts to diverse climatic conditions with the potential to support food and nutritional security worldwide. It is used as a vegetable, minor food crop and a fodder crop, being a rich source of proteins, minerals, and essential fatty acids. However, little effort has been made to decipher the genetic and molecular basis of various useful traits in this crop. Therefore, we considered three economically important traits i.e., flowering, maturity and seed weight of rice bean and identified the associated candidate genes employing an associative transcriptomics approach on 100 diverse genotypes out of 1800 evaluated rice bean accessions from the Indian National Genebank.ResultsThe transcriptomics-based genotyping of one-hundred diverse rice bean cultivars followed by pre-processing of genotypic data resulted in 49,271 filtered markers. The STRUCTURE, PCA and Neighbor-Joining clustering of 100 genotypes revealed three putative sub-populations. The marker-trait association analysis involving various genome-wide association study (GWAS) models revealed significant association of 82 markers on 48 transcripts for flowering, 26 markers on 22 transcripts for maturity and 22 markers on 21 transcripts for seed weight. The transcript annotation provided information on the putative candidate genes for the considered traits. The candidate genes identified for flowering include HSC80, P-II PsbX, phospholipid-transporting-ATPase-9, pectin-acetylesterase-8 and E3-ubiquitin-protein-ligase-RHG1A. Further, the WRKY1 and DEAD-box-RH27 were found to be associated with seed weight. Furthermore, the associations of PIF3 and pentatricopeptide-repeat-containing-gene with maturity and seed weight, and aldo–keto-reductase with flowering and maturity were revealed.ConclusionThis study offers insights into the genetic basis of key agronomic traits in rice bean, including flowering, maturity, and seed weight. The identified markers and associated candidate genes provide valuable resources for future exploration and targeted breeding, aiming to enhance the agronomic performance of rice bean cultivars. Notably, this research represents the first transcriptome-wide association study in pulse crop, uncovering the candidate genes for agronomically useful traits.

Multiomics-assisted characterization of rice-Yellow Stem Borer interaction provides genomic and mechanistic insights into stem borer resistance in rice.

By deploying a multi-omics approach, we unraveled the mechanisms that might help rice to combat Yellow Stem Borer infestation, thus providing insights and scope for developing YSB resistant rice varieties. Yellow Stem Borer (YSB), Scirpophaga incertulas (Walker) (Lepidoptera: Crambidae), is a major pest of rice, that can lead to 20-60% loss in rice production. Effective management of YSB infestation is challenged by the non-availability of adequate sources of resistance and poor understanding of resistance mechanisms, thus necessitating studies for generating resources to breed YSB resistant rice and to understand rice-YSB interaction. In this study, by using bulk-segregant analysis in combination with next-generation sequencing, Quantitative Trait Loci (QTL) intervals in five rice chromosomes were mapped that could be associated with YSB resistance at the vegetative phase in a resistant rice line named SM92. Further, multiple SNP markers that showed significant association with YSB resistance in rice chromosomes 1, 5, 10, and 12 were developed. RNA-sequencing of the susceptible and resistant lines revealedseveral genes present in the candidate QTL intervals to be differentially regulated upon YSB infestation. Comparative transcriptome analysis revealed a putative candidate gene that was predicted to encode an alpha-amylase inhibitor. Analysis of the transcriptome and metabolite profiles further revealed a possible link between phenylpropanoid metabolism and YSB resistance. Taken together, our study provides deeper insights into rice-YSB interaction and enhances the understanding of YSB resistance mechanism. Importantly, a promising breeding line and markers for YSB resistance have been developed that can potentially aid in marker-assisted breeding of YSB resistance among elite rice cultivars.

Meta QTL analysis for dissecting abiotic stress tolerance in chickpea

BackgroundChickpea is prone to many abiotic stresses such as heat, drought, salinity, etc. which cause severe loss in yield. Tolerance towards these stresses is quantitative in nature and many studies have been done to map the loci influencing these traits in different populations using different markers. This study is an attempt to meta-analyse those reported loci projected over a high-density consensus map to provide a more accurate information on the regions influencing heat, drought, cold and salinity tolerance in chickpea.ResultsA meta-analysis of QTL reported to be responsible for tolerance to drought, heat, cold and salinity stress tolerance in chickpeas was done. A total of 1512 QTL responsible for the concerned abiotic stress tolerance were collected from literature, of which 1189 were projected on a chickpea consensus genetic map. The QTL meta-analysis predicted 59 MQTL spread over all 8 chromosomes, responsible for these 4 kinds of abiotic stress tolerance in chickpea. The physical locations of 23 MQTL were validated by various marker-trait associations and genome-wide association studies. Out of these reported MQTL, CaMQAST1.1, CaMQAST4.1, CaMQAST4.4, CaMQAST7.8, and CaMQAST8.2 were suggested to be useful for different breeding approaches as they were responsible for high per cent variance explained (PVE), had small intervals and encompassed a large number of originally reported QTL. Many putative candidate genes that might be responsible for directly or indirectly conferring abiotic stress tolerance were identified in the region covered by 4 major MQTL- CaMQAST1.1, CaMQAST4.4, CaMQAST7.7, and CaMQAST6.4, such as heat shock proteins, auxin and gibberellin response factors, etc.ConclusionThe results of this study should be useful for the breeders and researchers to develop new chickpea varieties which are tolerant to drought, heat, cold, and salinity stresses.

Unique genetic architecture of prolificacy in 'Sikkim Primitive' maize unraveled through whole-genome resequencing-based DNA polymorphism.

'Sikkim Primitive' maize landrace, unique for prolificacy (7-9 ears per plant) possesses unique genomic architecture in branching and inflorescence-related gene(s), and locus Zm00001eb365210 encoding glycosyltransferases was identified as the putative candidate gene underlying QTL (qProl-SP-8.05) for prolificacy. The genotype possesses immense usage in breeding high-yielding baby-corn genotypes. 'Sikkim Primitive' is a native landrace of North Eastern Himalayas, and is characterized by having 7-9 ears per plant compared to 1-2 ears in normal maize. Though 'Sikkim Primitive' was identified in the 1960s, it has not been characterized at a whole-genome scale. Here, we sequenced the entire genome of an inbred (MGUSP101) derived from 'Sikkim Primitive' along with three non-prolific (HKI1128, UMI1200, and HKI1105) and three prolific (CM150Q, CM151Q and HKI323) inbreds. A total of 942,417 SNPs, 24,160 insertions, and 27,600 deletions were identified in 'Sikkim Primitive'. The gene-specific functional mutations in 'Sikkim Primitive' were classified as 10,847 missense (54.36%), 402 non-sense (2.015%), and 8,705 silent (43.625%) mutations. The number of transitions and transversions specific to 'Sikkim Primitive' were 666,021 and 279,950, respectively. Among all base changes, (G to A) was the most frequent (215,772), while (C to G) was the rarest (22,520). Polygalacturonate 4-α-galacturonosyltransferase enzyme involved in pectin biosynthesis, cell-wall organization, nucleotide sugar, and amino-sugar metabolism was found to have unique alleles in 'Sikkim Primitive'. The analysis further revealed the Zm00001eb365210 gene encoding glycosyltransferases as the putative candidate underlying QTL (qProl-SP-8.05) for prolificacy in 'Sikkim Primitive'. High-impact nucleotide variations were found in ramosa3 (Zm00001eb327910) and zeaxanthin epoxidase1 (Zm00001eb081460) genes having a role in branching and inflorescence development in 'Sikkim Primitive'. The information generated unraveled the genetic architecture and identified key genes/alleles unique to the 'Sikkim Primitive' genome. This is the first report of whole-genome characterization of the 'Sikkim Primitive' landrace unique for its high prolificacy.

Mining genomic regions associated with agronomic and biochemical traits in quinoa through GWAS

Quinoa (Chenopodium quinoa Willd.), an Andean crop, is a facultative halophyte food crop recognized globally for its high nutritional value and plasticity to adapt to harsh conditions. We conducted a genome-wide association study on a diverse set of quinoa germplasm accessions. These accessions were evaluated for the following agronomic and biochemical traits: days to 50% flowering (DTF), plant height (PH), panicle length (PL), stem diameter (SD), seed yield (SY), grain diameter (GD), and thousand-grain weight (TGW). These accessions underwent genotyping-by-sequencing using the DNBSeq-G400R platform. Among all evaluated traits, TGW represented maximum broad-sense heritability. Our study revealed average SNP density of ≈ 3.11 SNPs/10 kb for the whole genome, with the lowest and highest on chromosomes Cq1B and Cq9A, respectively. Principal component analysis clustered the quinoa population in three main clusters, one clearly representing lowland Chilean accessions, whereas the other two groups corresponded to germplasm from the highlands of Peru and Bolivia. In our germplasm set, we estimated linkage disequilibrium decay to be ≈ 118.5 kb. Marker-trait analyses revealed major and consistent effect associations for DTF on chromosomes 3A, 4B, 5B, 6A, 7A, 7B and 8B, with phenotypic variance explained (PVE) as high as 19.15%. Nine associations across eight chromosomes were also found for saponin content with 20% PVE by qSPN5A.1. More QTLs were identified for PL and TGW on multiple chromosomal locations. We identified putative candidate genes in the genomic regions associated with DTF and saponin content. The consistent and major-effect genomic associations can be used in fast-tracking quinoa breeding for wider adaptation across marginal environments.

Genetic insights into agronomic and morphological traits of drug-type cannabis revealed by genome-wide association studies

Cannabis sativa L., previously concealed by prohibition, is now a versatile and promising plant, thanks to recent legalization, opening doors for medical research and industry growth. However, years of prohibition have left the Cannabis research community lagging behind in understanding Cannabis genetics and trait inheritance compared to other major crops. To address this gap, we conducted a comprehensive genome-wide association study (GWAS) of nine key agronomic and morphological traits, using a panel of 176 drug-type Cannabis accessions from the Canadian legal market. Utilizing high-density genotyping-by-sequencing (HD-GBS), we successfully generated dense genotyping data in Cannabis, resulting in a catalog of 800 K genetic variants, of which 282 K common variants were retained for GWAS analysis. Through GWAS analysis, we identified 18 markers significantly associated with agronomic and morphological traits. Several identified markers exert a substantial phenotypic impact, guided us to putative candidate genes that reside in high linkage-disequilibrium (LD) with the markers. These findings lay a solid foundation for an innovative cannabis research, leveraging genetic markers to inform breeding programs aimed at meeting diverse needs in the industry.

Gene expression profiles of white bass (Morone chrysops) and hybrid striped bass (M. chrysops x M. saxatilis) gill tissue following Flavobacterium covae infection

Columnaris disease is a prevalent disease in freshwater environments caused by the ubiquitous aquatic pathogen Flavobacterium species. Adhesion to the external mucosal surfaces of fishes is the initial stage of infection, and the gills specifically have been identified as both a primary target and release site for this pathogen. Demonstrated here and in previous research, the hybrid striped bass (Morone chrysops x M. saxatilis), a prominent United States aquaculture product, is more susceptible to infection with F. covae than the maternal white bass (M. chrysops) parental species. To further elucidate the mechanisms underlying differences in resistance between these fish we examined gill gene expression profiles using RNA sequencing at different timepoints after F. covae infection. Patterns of differential gene expression and association with key enrichment terms indicate the effective immune response observed in white bass includes the up-regulation of multiple cytokines (IL-1β, IL-17C, TNF-α, G-CSF, IL-8, CCL16, CXCL9), hepcidins (HAMP and HAMP2), ribosomal subunit components (e.g., RPL13), and, interestingly, the down-regulation of leptin (LEPA) during initial (1 – 4 h) stages of infection. Conversely, up-regulation of the same genes was not detected in hybrid striped bass until 24 h after infection, indicating a delay in immune response mechanisms that is ultimately ineffective in protecting the host, as this was concurrent with the onset of mortality in these fish. Collectively, the presented results include several putative pathways and candidate genes for further investigation toward characterizing immune defense mechanisms underlying the resistance (white bass) and susceptibility (hybrid striped bass) for selective breeding efforts and/or biotechnological intervention.

GWAS in a Collection of Bulgarian Old and Modern Bread Wheat Accessions Uncovers Novel Genomic Loci for Grain Protein Content and Thousand Kernel Weight.

Genetic enhancement of grain production and quality is a priority in wheat breeding projects. In this study, we assessed two key agronomic traits-grain protein content (GPC) and thousand kernel weight (TKW)-across 179 Bulgarian contemporary and historic varieties and landraces across three growing seasons. Significant phenotypic variation existed for both traits among genotypes and seasons, and no discernible difference was evident between the old and modern accessions. To understand the genetic basis of the traits, we conducted a genome-wide association study with MLM using phenotypic data from the crop seasons, best linear unbiased estimators, and genotypic data from the 25K Infinium iSelect array. As a result, we detected 16 quantitative trait nucleotides (QTNs) associated with GPC and 15 associated with TKW, all of which passed the false discovery rate threshold. Seven loci favorably influenced GPC, resulting in an increase of 1.4% to 8.1%, while four loci had a positive impact on TKW with increases ranging from 1.9% to 8.4%. While some loci confirmed previously published associations, four QTNs linked to GPC on chromosomes 2A, 7A, and 7B, as well as two QTNs related to TKW on chromosomes 1B and 6A, may represent novel associations. Annotations for proteins involved in the senescence-associated nutrient remobilization and in the following buildup of resources required for seed germination have been found for selected putative candidate genes. These include genes coding for storage proteins, cysteine proteases, cellulose-synthase, alpha-amylase, transcriptional regulators, and F-box and RWP-RK family proteins. Our findings highlight promising genomic regions for targeted breeding programs aimed at improving grain yield and protein content.

Genetic architecture of post-harvest tuber quality traits in bush yam (Dioscorea praehensilis Benth.) germplasm through association mapping

IntroductionBush yam (Dioscorea praehensilis Benth.) is an important semi-domesticated food crop in West Africa. Limited information on the genetic architecture and its poor post-harvest tuber quality traits significantly hinder its use as food and source of income. Hence, dissecting the genetics underlying the expression of its post-harvest tuber quality traits is essential for establishing proper breeding schemes.MethodsIn this study, 138 D. praehensilis accessions collected in Ghana were sequenced using Diversity Array Technology (DArTSeq). The materials were profiled for dry matter content (DMC), tuber flesh oxidation (TBOXI) and for tuber flesh hardness (TBhard) during two cropping seasons.Results and discussionDiversity assessment using population structure, principal component analysis and hierarchical clustering methods revealed the presence of three major groups. Six genetic models were used for the trait association analysis using multiple random locus mixed linear model (MrMLM). Sixteen SNP markers distributed across the yam genome were identified to be associated with the evaluated traits. The associated SNP markers displayed a phenotypic variance ranged from 4.22% in TBHard to 16.92% in TBOXI. A total 25 putative candidate genes were identified around the SNP markers. The putative genes were identified to play key roles in tuber bulking, oxidative browning and starch hydroxylase. This study provides a valuable insight on the genetics underlying tuber quality traits in bush yam and opens avenues for developing genomic resources to improve D. praehensilis.

Abstract LB146: Multi Omics analyses identified novel loci and genes for lung cancer risk among European Descendants

Abstract Introduction Genome-wide association studies (GWAS) have identified &amp;gt;60 genomic loci for lung cancer risk. However, causal genes and the underlying biological mechanisms for most of these loci remain unknown. Therefore, we conducted a multi-omics study to identify lung cancer susceptibility genes. Method We first conducted a transcriptome-wide association study (TWAS) using S-PrediXcan framework. Whole transcriptome data from adjacent-normal lung tissue samples and genomic data from 304 European-ancestry lung cancer patients were used to build genetic prediction models for expression levels of protein-coding genes and lincRNAs. The prediction models were then applied to GWAS meta-analysis results for lung cancer with 39,363 cases and 621,480 controls of European descents from TRICL-ILCCO, the UK Biobank, and FinnGen. COJO was used to assess whether those significant genes were independent of proximal (±1.5 Mb) GWAS-identified risk variants. To replicate our TWAS-identified genes, we used data from GTEx version 8 normal lung tissue (N=444) to build imputation models and then run association analyses. We acquired gene (N=107) and protein expression data (N=111) from tumor and matched adjacent-normal lung tissues from European-ancestry participants in the Clinical Proteomic Tumor Analysis Consortium. Paired Wilcoxon rank sum tests were then conducted to assess whether identified genes and their corresponding proteins were expressed differentially. Results Out of 18,850 genes (read count &amp;gt;6 and TPM &amp;gt;0.1 in at least 20% samples), 6,754 protein-coding genes and 802 lincRNAs were predicted reliably using genetic variants (R&amp;gt;0.1 and P&amp;lt;0.05). Among them, genetically proxied expression levels of 24 genes located at 15 loci were significantly associated with lung cancer risk at a Bonferroni adjusted P &amp;lt;0.05. Four genes were located at four novel loci, including SERF1A at 5q13.2, SMIM33 at 5q31.2, MUC5B at 11p15.5, and RASSF10 at 11p15.2. Six putative candidate genes, namely H4C13, HCP5B, STN1, COPS2, SKIV2L, and LINC00243 resided in previously GWAS-identified lung cancer loci but have not been reported. Of these six genes, SKIV2L (Padjust=1.49e-5) and LINC00243 (Padjust=3.47e-5) were independently associated with lung cancer risk even after adjusting for GWAS-identified variants. Among 24 identified genes, 16 showed a consistent significant association with lung cancer risk (p&amp;lt;0.05) based on the prediction models built using GTEx data. Of ten unreported or novel genes, MUC5B, SMIM33, SERF1A, STN1, COPS2, and LINC00243 showed differential gene expression at P &amp;lt;0.05 and consistent association direction with TWAS results. Three proteins, STN1, COPS2, and SKIV2L, showed differential expression in tumor and adjacent-normal tissue at P&amp;lt;0.05, which is consistent with our TWAS direction. Conclusion Our findings offer novel insights into lung cancer carcinogenesis by uncovering new genes and loci. Citation Format: Shuai Xu, Yaohua Yang, Tianying Zhao, Jiajun Shi, Jie Ping, Wanqing Wen, Hui Cai, Xingyi Guo, Ran Tao, Xiao-Ou Shu, Wei Zheng, Jirong Long, Qiuyin Cai. Multi Omics analyses identified novel loci and genes for lung cancer risk among European Descendants [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB146.

Genome-wide analysis of the PME gene family reveals its role in suppressing fruit lignification in pear

In pears, the presence of stone cells adversely affects fruit quality. Pectin methylesterase (PME) plays various roles in plant biology, including lignin biosynthesis. However, only a limited fraction has been functionally characterized, and the distribution and function of PME in many Rosaceae trees remain unexplored. In this study, we identified 396 putative PME family candidate genes, with 81 in Pyrus bretschneideri, 92 in Malus domestica, 62 in Fragaria vesca, 65 in Prunus mume, 15 in Pyrus communis, and 81 in Pyrus pyrifolia. Leveraging insights from model plants, we categorized PME family genes into four groups. Additionally, the evolution of the PME gene family was shaped by various gene duplication events, primarily dispersed duplication, influenced by purifying selection. A specific gene, Pbr031522.1, designated PbPME35, emerged as a candidate associated with lignin biosynthesis in pear fruits, supported by RNA-seq data. The role of PbPME35 in repressing lignification was validated through its overexpression in pear callus and Arabidopsis. Overall, our findings highlight the ability of PbPME35 to reduce lignin content in pear fruit by downregulating the expression levels of lignin biosynthesis genes. These findings provide new insights into the characteristics of PME genes and their role in regulating lignification in pear fruits.

Mapping the genetic architecture of low-temperature stress tolerance in citron watermelon.

Sweet-fleshed watermelon (Citrullus lanatus) is an important vegetable crop of the tropical origin. It is widely grown and consumed around the world for its hydration and nutritional quality values. Low-temperature stress can affect early planting, seedling establishment, and expansion of crop production to new areas. A collection of 122 citron watermelon (Citrullus amarus) accessions were obtained from the USDA's National Plant Germplasm Repository System gene bank in Griffin, GA. The accessions were genotyped using whole genome resequencing to generate single nucleotide polymorphisms (SNPs) molecular markers and screened under cold-stressed and non-stressed control conditions. Four low-temperature stress tolerance related traits including shoot biomass, vine length, maximum quantum efficiency of photosystem II, and chlorophyll content were measured under cold-stressed and non-stressed control treatment conditions. Correlation analysis revealed the presence of positive relationships among traits. Broad-sense heritability for all traits ranged from 0.35 to 0.73, implying the presence of genetic contributions to the observed phenotypic variation. Genomic regions underlying these traits across several citron watermelon chromosomes were identified. Four low-temperature stress tolerance related putative candidate genes co-located with the peak SNPs from genome-wide association study. These genomic regions and marker information could potentially be used in molecular breeding to accelerate genetic improvements for low-temperature stress tolerance in watermelon.

Genome-Wide Association Study Revealed Putative SNPs and Candidate Genes Associated with Growth and Meat Traits in Japanese Quail.

The search for SNPs and candidate genes that determine the manifestation of major selected traits is one crucial objective for genomic selection aimed at increasing poultry production efficiency. Here, we report a genome-wide association study (GWAS) for traits characterizing meat performance in the domestic quail. A total of 146 males from an F2 reference population resulting from crossing a fast (Japanese) and a slow (Texas White) growing breed were examined. Using the genotyping-by-sequencing technique, genomic data were obtained for 115,743 SNPs (92,618 SNPs after quality control) that were employed in this GWAS. The results identified significant SNPs associated with the following traits at 8 weeks of age: body weight (nine SNPs), daily body weight gain (eight SNPs), dressed weight (33 SNPs), and weights of breast (18 SNPs), thigh (eight SNPs), and drumstick (three SNPs). Also, 12 SNPs and five candidate genes (GNAL, DNAJC6, LEPR, SPAG9, and SLC27A4) shared associations with three or more traits. These findings are consistent with the understanding of the genetic complexity of body weight-related traits in quail. The identified SNPs and genes can be used in effective quail breeding as molecular genetic markers for growth and meat characteristics for the purpose of genetic improvement.

Identification of genetic loci and candidate genes underlying freezing tolerance in wheat seedlings.

Ten stable loci for freezing tolerance (FT) in wheat were detected by genome-wide association analysis. The putative candidate gene TaRPM1-7BL underlying the major locus QFT.ahau-7B.2 was identified and validated. Frost damage restricts wheat growth, development, and geographical distribution. However, the genetic mechanism of freezing tolerance (FT) remains unclear. Here, we evaluated FT phenotypes of 245 wheat varieties and lines, and genotyped them using a Wheat 90K array. The association analysis showed that ten stable loci were significantly associated with FT (P < 1 × 10-4), and explained 6.45-26.33% of the phenotypic variation. In particular, the major locus QFT.ahau-7B.2 was consistently related to all nine sets of FT phenotypic data. Based on five cleaved amplified polymorphic sequence (CAPS) markers closely linked to QFT.ahau-7B.2, we narrowed down the target region to the 570.67-571.16Mb interval (0.49Mb) on chromosome 7B, in which four candidate genes were annotated. Of these, only TaRPM1-7BL exhibited consistent differential expression after low temperature treatment between freezing-tolerant and freezing-sensitive varieties. The results of cloning and whole-exome capture sequencing indicated that there were two main haplotypes for TaRPM1-7BL, including freezing-tolerant Hap1 and freezing-sensitive Hap2. Based on the representative SNP (+1956, A/G), leading to an amino acid change in the NBS domain, a CAPS marker (CAPS-TaRPM1-7BL) was developed and validated in 431 wheat varieties (including the above 245 materials) and 318 F2 lines derived from the cross of 'Annong 9267' (freezing-tolerant) × 'Yumai 9' (freezing-sensitive). Subsequently, the TaRPM1-7BL gene was silenced in 'Yumai 9' by virus-induced gene silencing (VIGS), and these silenced wheat seedlings exhibited enhanced FT phenotypes, suggesting that TaRPM1-7BL negatively regulates FT. These findings are valuable for understanding the complex genetic basis of FT in wheat.