Inferring Mycobacterium Tuberculosis Drug Resistance and Transmission using Whole-genome Sequencing in a High TB-burden Setting in China

Objective China is among the 30 countries with a high burden of tuberculosis(TB)worldwide,and TB remains a public health concern.Kashgar Prefecture in the southern Xinjiang Autonomous Region is considered as one of the highest TB burden regions in China.However,molecular epidemiological studies of Kashgar are lacking.Methods A population-based retrospective study was conducted using whole-genome sequencing(WGS)to determine the characteristics of drug resistance and the transmission patterns.Results A total of 1,668 isolates collected in 2020 were classified into lineages 2(46.0%),3(27.5%),and 4(26.5%).The drug resistance rates revealed by WGS showed that the top three drugs in terms of the resistance rate were isoniazid(7.4%,124/1,668),streptomycin(6.0%,100/1,668),and rifampicin(3.3%,55/1,668).The rate of rifampicin resistance was 1.8%(23/1,290)in the new cases and 9.4%(32/340)in the previously treated cases.Known resistance mutations were detected more frequently in lineage 2 strains than in lineage 3 or 4 strains,respectively:18.6%vs.8.7 or 9%,P<0.001.The estimated proportion of recent transmissions was 25.9%(432/1,668).Multivariate logistic analyses indicated that sex,age,occupation,lineage,and drug resistance were the risk factors for recent transmission.Despite the low rate of drug resistance,drug-resistant strains had a higher risk of recent transmission than the susceptible strains(adjusted odds ratio,1.414;95%CI,1.023–1.954;P=0.036).Among all patients with drug-resistant tuberculosis(DR-TB),78.4%(171/218)were attributed to the transmission of DR-TB strains.Conclusion Our results suggest that drug-resistant strains are more transmissible than susceptible strains and that transmission is the major driving force of the current DR-TB epidemic in Kashgar.

Population genetics of marmosets in Asian primate research centers and loci associated with epileptic risk revealed by whole-genome sequencing

The common marmoset(Callithrix jacchus)has emerged as a valuable nonhuman primate model in biomedical research with the recent release of high-quality reference genome assemblies.Epileptic marmosets have been independently reported in two Asian primate research centers.Nevertheless,the population genetics within these primate centers and the specific genetic variants associated with epilepsy in marmosets have not yet been elucidated.Here,we characterized the genetic relationships and risk variants for epilepsy in 41 samples from two epileptic marmoset pedigrees using whole-genome sequencing.We identified 14558184 single nucleotide polymorphisms(SNPs)from the 41 samples and found higher chimerism levels in blood samples than in fingernail samples.Genetic analysis showed fourth-degree of relatedness among marmosets at the primate centers.In addition,SNP and copy number variation(CNV)analyses suggested that the WW domain-containing oxidoreductase(WWOX)and Tyrosine-protein phosphatase nonreceptor type 21(PTPN21)genes may be associated with epilepsy in marmosets.Notably,KCTD18-like gene deletion was more common in epileptic marmosets than control marmosets.This study provides valuable population genomic resources for marmosets in two Asian primate centers.Genetic analyses identified a reasonable breeding strategy for genetic diversity maintenance in the two centers,while the case-control study revealed potential risk genes/variants associated with epilepsy in marmosets.

Safety assessment of a novel marine multi-stress-tolerant yeast Meyerozyma guilliermondii GXDK6 according to phenotype and whole genome-sequencing analysis

The application of microorganisms as probiotics is limited due to lack of safety evaluation.Here,a novel multi-stress-tolerant yeast Meyerozyma guilliermondii GXDK6 with aroma-producing properties was identified from marine mangrove microorganisms.Its safety and probiotic properties were assessed in accordance with phenotype and whole-genome sequencing analysis.Results showed that the genes and phenotypic expression of related virulence,antibiotic resistance and retroelement were rarely found.Hyphal morphogenesis genes(SIT4,HOG1,SPA2,ERK1,ICL1,CST20,HSP104,TPS1,and RHO1)and phospholipase secretion gene(VPS4)were annotated.True hyphae and phospholipase were absent.Only one retroelement(Tad1-65_BG)was found.Major biogenic amines(BAs)encoding genes were absent,except for spermidine synthase(JA9_002594),spermine synthase(JA9_004690),and tyrosine decarboxylase(inx).The production of single BAs and total BAs was far below the food-defined thresholds.GXDK6 had no resistance to common antifungal drugs.Virulence enzymes,such as gelatinase,DNase,hemolytic,lecithinase,and thrombin were absent.Acute toxicity test with mice demonstrated that GXDK6 is safe.GXDK6 has a good reproduction ability in the simulation gastrointestinal tract.GXDK6 also has a strong antioxidant ability,β-glucosidase,and inulinase activity.To sum up,GXDK6 is considered as a safe probiotic for human consumption and food fermentation.

Genome-wide scan for selection signatures based on whole-genome re-sequencing in Landrace and Yorkshire pigs

We performed a genome-wide scan to detect selection signatures that showed evidence of positive selection in the domestication process by re-sequencing the whole genomes of Landrace and Yorkshire pigs.Fifteen annotated elements with 13 associated genes were identified using the Z-transformed FST(Z(FST))method,and 208 annotated elements with 140 associated genes were identified using the Z-transformed heterozygosity(ZHp)method.The functional analysis and the results of previous studies showed that most of the candidate genes were associated with basic metabolism,disease resistance,cellular processes,and biochemical signals,and several were related to body morphology and organs.They included PPP3CA,which plays an essential role in the transduction of intracellular Ca2+-mediated signals,and WWTR1,which plays a pivotal role in organ size control and tumor suppression.These results suggest that genes associated with body morphology were subject to selection pressure during domestication,whereas genes involved in basic metabolism and disease resistance were subject to selection during artificial breeding.Our findings provide new insights into the potential genetic variation of phenotypic diversity in different pig breeds and will help to better understand the selection effects of modern breeding in Landrace and Yorkshire pigs.

Cost-effective low-coverage whole-genome sequencing assay for the risk stratification of gastric cancer

BACKGROUND Gastric cancer(GC), a multifactorial disease, is caused by pathogens, such as Helicobacter pylori(H. pylori) and Epstein-Barr virus(EBV), and genetic components.AIM To investigate microbiomes and host genome instability by cost-effective,low-coverage wholegenome sequencing,as biomarkers for GC subtyping.METHODS Samples from 40 GC patients were collected from Taizhou Hospital,Zhejiang Province,affiliated with Wenzhou Medical University.DNA from the samples was subjected to low-coverage wholegenome sequencing with a median genome coverage of 1.86×(range:1.03×to 3.17×) by Illumina×10,followed by copy number analyses using a customized bioinformatics workflow ultrasensitive chromosomal aneuploidy detector.RESULTS Of the 40 GC samples,20 (50%) were found to be enriched with microbiomes.EBV DNA was detected in 5 GC patients (12.5%).H.pylori DNA was found in 15 (37.5%) patients.The other 20(50%) patients were found to have relatively higher genomic instability.Copy number amplifications of the oncogenes,ERBB2 and KRAS,were found in 9 (22.5%) and 7 (17.5%) of the GC samples,respectively.EBV enrichment was found to be associated with tumors in the gastric cardia and fundus.H.pylori enrichment was found to be associated with tumors in the pylorus and antrum.Tumors with elevated genomic instability showed no localization and could be observed in any location.Additionally,H.pylori-enriched GC was found to be associated with the Borrmann type Ⅱ/Ⅲ and gastritis history.EBV-enriched GC was not associated with gastritis.No statistically significant correlation was observed between genomic instability and gastritis.Furthermore,these three different molecular subtypes showed distinct survival outcomes (P=0.019).EBV-positive tumors had the best prognosis,whereas patients with high genomic instability (CIN+) showed the worst survival.Patients with H.pylori infection showed intermediate prognosis compared with the other two subtypes.CONCLUSION Thus,using low-coverage whole-genome sequencing,GC can be classified into three categories based on disease etiology;this classification may prove useful for GC diagnosis and precision medicine.

Analysis of the genomic landscape of primary central nervous system lymphoma using whole-genome sequencing in Chinese patients

Primary central nervous system lymphoma(PCNSL)is an uncommon non-Hodgkin’s lymphoma with poor prognosis.This study aimed to depict the genetic landscape of Chinese PCNSLs.Whole-genome sequencing was performed on 68 newly diagnosed Chinese PCNSL samples,whose genomic characteristics and clinicopathologic features were also analyzed.Structural variations were identified in all patients with a mean of 349,which did not significantly influence prognosis.Copy loss occurred in all samples,while gains were detected in 77.9%of the samples.The high level of copy number variations was significantly associated with poor progression-free survival(PFS)and overall survival(OS).A total of 263 genes mutated in coding regions were identified,including 6 newly discovered genes(ROBO2,KMT2C,CXCR4,MYOM2,BCLAF1,and NRXN3)detected in≥10%of the cases.CD79B mutation was significantly associated with lower PFS,TMSB4X mutation and high expression of TMSB4X protein was associated with lower OS.A prognostic risk scoring system was also established for PCNSL,which included Karnofsky performance status and six mutated genes(BRD4,EBF1,BTG1,CCND3,STAG2,and TMSB4X).Collectively,this study comprehensively reveals the genomic landscape of newly diagnosed Chinese PCNSLs,thereby enriching the present understanding of the genetic mechanisms of PCNSL.

Complete Genome Sequencing and Analysis of Rehmannia Mosaic Virus Isolate from Shanxi Province

Using double-stranded RNA(dsRNA)technology and sequence-independent amplification(SIA),the molecular identification on infected Rehmannia glutinosa in the field with mosaic symptoms was performed and the whole-genome of the Rehmannia mosaic virus(ReMV)Shanxi isolate(ReMV-SX)was sequenced.Sequencing analysis showed that the virus that infected Rehmannia glutinosa was Rehmannia mosaic virus(ReMV).The full-length of the obtained ReMV-SX sequence(GenBank accession no.JX575184)was 6395 nt,containing four open reading frames(ORFs).The sequence homology analysis of the complete nucleotide sequence showed that ReMV-SX was 93.8%-97.0%homologous to ReMV in Tobamovirus subgroup Ⅰ,while only 49.8%-58.9%homologous to the isolates in subgroups Ⅱ and Ⅲ of the same genus.Phylogenetic analysis showed that ReMV-SX and ReMV-Henan formed a separate branch and had the closest genetic relationship.The results laid the foundation for ongoing researches in the taxonomic status and evolution of ReMV and for further investigating the pathogenic mechanism of ReMV infecting Rehmannia glutinosa.

Molecular diagnosis of autosomal recessive cerebellar ataxia in the whole exome/genome sequencing era

Autosomal recessive cerebellar ataxias(ARCA) are a clinically and genetically heterogeneous group of rare neurodegenerative disorders characterized by autosomal recessive inheritance and an early age of onset. Progressive ataxia is usually the prominent symptom and is often associated with other neurological or additional features. ARCA classification still remains controversial even though different approaches have been proposed over the years. Furthermore, ARCA molecular diagnosis has been a challenge due to phenotypic overlap and increased genetic heterogeneity observed within this group of disorders. Friedreich's ataxia and ataxia telangiectasia have been reported as the most frequent and well-studied forms of ARCA. Significant progress in understanding the genetic etiologies of the ARCA has been achieved during the last 15 years. The methodological revolution that has been observed in genetics over the last few years has contributed significantly to the molecular diagnosis of rare diseases including the ARCAs. Development of high throughput technologies has resulted in the identification of new ARCA genes and novel mutations in known ARCA genes. Therefore,an improvement in the molecular diagnosis of ARCA is expected. Moreover, based on the fact that many patients still remain undiagnosed, additional forms of ataxia are expected to be identified. We hereby review the current knowledge on the ARCAs, focused on the genetic findings of the most common forms that were molecularly characterized before the whole exome/genome era, as well as the most recently described forms that have been elucidated with the use of these novel technologies. The significant contribution of wholeexome sequencing or whole-genome sequencing in the molecular diagnosis of ARCAs is discussed.

Study on Mutation and Its Characteristics of Mycobacterium Tuberculosis Multidrug Resistance Genes Based on Whole-genome Sequencing

Objective: The increase in the development of resistance to multiple drugs in mycobacterium tuberculosis(MTB) poses a substantial obstacle to the prevention and management of tuberculosis(TB). A thorough investigation of the genotypes linked to multidrug resistance is crucial for comprehending the mechanisms underlying drug resistance. The objective of this research was to assess the attributes of gene mutations associated with multidrug resistance in clinical isolates of mycobacterium tuberculosis through the utilization of whole-genome sequencing. Methods: A total of 124 strains of drug-resistant mycobacterium tuberculosis were collected, and the genomic DNA of both multidrug-resistant and rifampin-resistant strains were extracted and sequenced. Bioinformatics was used to analyze and compare multidrug resistance-related gene sequences in order to detect the variation of multidrug resistance genes. Results: The results revealed that the resistance spectrum of XDR-TB group was much wider than that of the other three groups, with the RR-TB group having the most limited resistance spectrum.Within the MDR-TB strains, fabG1 exhibited the highest frequency of mutations, while RRS, gyrA, and rpoB were identified as the predominant mutation bases in XDR-TB strains. Additionally, rpoB emerged as the primary mutation base in MDR-TB and RR-TB strains. Notably, the fabG1 mutation was found to be closely associated with PDR-TB. Furthermore, the correlation between the mutation rate of rpoB and multidrug resistance was deemed to be of secondary importance. Conclusion: Various strains of MTB exhibited distinct mechanisms of drug resistance, with the gene mutations of fabG1,RRS, gyrA, and rpoB potentially playing a pivotal role in the development of drug resistance. However, the primary genes responsible for drug resistance mutations varied among different strains of TB.

Microdeletion on Xq27.1 in a Chinese VACTERL-Like Family with Kidney and Anal Anomalies

Objective VATER/VACTERL-like association is associated with adverse pregnancy outcomes.Genetic evidence of this disorder is sporadic.In this study,we aimed to provide genetic insights to improve the diagnosis of VACTERL.Methods We have described a Chinese family in which four members were affected by renal defects or agenesis,anal atresia,and anovaginal fistula,which is consistent with the diagnosis of a VACTERL-like association.Pedigree and genetic analyses were conducted using genome and exome sequencing.Results Segregation analysis revealed the presence of a recessive X-linked microdeletion in two living affected individuals,harboring a 196–380 kb microdeletion on Xq27.1,which was identified by familial exome sequencing.Genome sequencing was performed on the affected male,confirming a-196 kb microdeletion in Xq27.1,which included a 28%loss of the CDR-1 gene.Four family members were included in the co-segregation analysis,and only VACTERL-like cases with microdeletions were reported in X27.1.Conclusion These results suggest that the 196–380 kb microdeletion in Xq27.1 could be a possible cause of the VATER/VACTERL-like association.However,further genetic and functional analyses are required to confirm or rule out genetic background as the definitive cause of the VACTERL association.

Population genomic data reveal low genetic diversity,divergence and local adaptation among threatened Reeves's Pheasant(Syrmaticus reevesii)

Population genomic data could provide valuable information for conservation efforts;however,limited studies have been conducted to investigate the genetic status of threatened pheasants.Reeves’s Pheasant(Syrmaticus reevesii)is facing population decline,attributed to increases in habitat loss.There is a knowledge gap in understanding the genomic status and genetic basis underlying the local adaptation of this threatened bird.Here,we used population genomic data to assess population structure,genetic diversity,inbreeding patterns,and genetic divergence.Furthermore,we identified candidate genes linked with adaptation across the current distribution of Reeves’s Pheasant.The present study assembled the first de novo genome sequence of Reeves’s Pheasant and annotated 19,458 genes.We also sequenced 30 individuals from three populations(Dabie Mountain,Shennongjia,Qinling Mountain)and found that there was clear population structure among those populations.By comparing with other threatened species,we found that Reeves’s Pheasants have low genetic diversity.Runs of homozygosity suggest that the Shennongjia population has experienced serious inbreeding.The demographic history results indicated that three populations experienced several declines during the glacial period.Local adaptative analysis among the populations identified 241 candidate genes under directional selection.They are involved in a large variety of processes,including the immune response and pigmentation.Our results suggest that the three populations should be considered as three different conservation units.The current study provides genetic evidence for conserving the threatened Reeves’s Pheasant and provides genomic resources for global biodiversity management.

Whole-genome sequencing to detect mutations associated with resistance to insecticides and Bt proteins in Spodoptera frugiperda

The fall armyworm(FAW),Spodoptera frugiperda,is a major pest native to the Americas that has recently invaded the Old World.Point mutations in the target-site proteins acetylcholinesterase-1(ace-1),voltage-gated sodium channel(VGSC)and ryanodine receptor(RyR)have been identified in S.frugiperda as major resistance mechanisms to organophosphate,pyrethroid and diamide insecticides respectively.Mutations in the adenosine triphosphate-binding cassette transporter C2 gene(ABCC2)have also been identified to confer resistance to Cry IF protein.In this study,we applied a whole-genome sequencing(WGS)approach to identify point mutations in the target-site genes in 150 FAW individuals collected from China,Malawi,Uganda and Brazil.This approach revealed three amino acid substitutions(A201S,G227A and F290V)of S.frugiperda ace-1,which are known to be associated with organophosphate resistance.The Brazilian population had all three ace-1 point mutations and the 227A allele(mean frequency=0.54)was the most common.Populations from China,Malawi and Uganda harbored two of the three ace-1 point mutations(A201S and F290V)with the 290V allele(0.47-0.58)as the dominant allele.Point mutations in VGSC(T929I,L932F and L1014F)and RyR(I4790M and G4946E)were not detected in any of the 150 individuals.A novel 12-bp insertion mutation in exon 15 of the ABCC2 gene was identified in some of the Brazilian individuals but absent in the invasive populations.Our results not only demonstrate robustness of the WGS-based genomic approach for detection of resistance mutations,but also provide insights for improvement of resistance management tactics in S.frugiperda.

Whole-genome sequencing of monozygotic twins discordant for schizophrenia indicates multiple genetic risk factors for schizophrenia

Schizophrenia is a common disorder with a high heritability, but its genetic architecture is still elusive.We implemented whole-genome sequencing(WGS) analysis of 8 families with monozygotic(MZ) twin pairs discordant for schizophrenia to assess potential association of de novo mutations(DNMs) or inherited variants with susceptibility to schizophrenia. Eight non-synonymous DNMs(including one splicing site) were identified and shared by twins, which were either located in previously reported schizophrenia risk genes(p.V24689 I mutation in TTN, p.S2506 T mutation in GCN1L1, IVS3+1G > T in DOCK1) or had a benign to damaging effect according to in silico prediction analysis. By searching the inherited rare damaging or loss-of-function(LOF) variants and common susceptible alleles from three classes of schizophrenia candidate genes, we were able to distill genetic alterations in several schizophrenia risk genes, including GAD1, PLXNA2, RELN and FEZ1. Four inherited copy number variations(CNVs; including a large deletion at 16p13.11) implicated for schizophrenia were identified in four families, respectively. Most of families carried both missense DNMs and inherited risk variants, which might suggest that DNMs, inherited rare damaging variants and common risk alleles together conferred to schizophrenia susceptibility. Our results support that schizophrenia is caused by a combination of multiple genetic factors, with each DNM/variant showing a relatively small effect size.

Genomic landscapes of Chinese sporadic autism spectrum disordersrevealed by whole-genome sequencing

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with considerable clinical and genetic heterogeneity.In this study,we identified all classes of genomic variants from whole-genome sequencing (WGS) dataset of 32 Chinese trios with ASD,including de novo mutations,inherited variants,copy number variants (CNVs) and genomic structural variants.A higher mutation rate (Poisson test,P<2.2×10) in exonic (1.37×10) and 3’-UTR regions (1.42×10) was revealed in comparison with that of whole genome (1.05×10).Using an integrated model,we identified 87 potentially risk genes (P<0.01) from 4832 genes harboring various rare deleterious variants,including CHD8 and NRXN2,implying that the disorders may be in favor to multiple-hit.In particular,frequent rare inherited mutations of several microcephaly-associated genes (ASPM,WDR62,and ZNF335)were found in ASD.In chromosomal structure analyses,we found four de novo CNVs and one de novo chromosomal rearrangement event,including a de novo duplication of UBE3A-containing region at 15q11.2-q13.1,which causes Angelman syndrome and microcephaly,and a disrupted TNR due to de novo chromosomal translocation t (1;5) (q25.1;q33.2).Taken together,our results suggest that abnormalities of centrosomal function and chromatin remodeling of the microcephaly-associated genes may be implicated in pathogenesis of ASD.Adoption of WGS as a new yet efficient technique to illustrate the full genetic spectrum in complex disorders,such as ASD,could provide novel insights into pathogenesis,diagnosis and treatment.

Draft genome sequence of a less-known wild Vigna: Beach pea(V. marina cv. ANBp-14-03)

Beach pea or beach cowpea(Vigna marina(Burm.)Merr.)belongs to the family Fabaceae.It is a close relative of cultivated Vigna species such as adzuki bean(V.angularis),cowpea(V.unguiculata),mung bean(V.radiata),and blackgram(V.mungo),and is distributed throughout the tropics.With its ability to tolerate salt stress,beach pea has great potential to contribute salt-tolerance genes for developing salt-tolerant cultivars in cultivated Vigna species.However,it is still underutilized in Vigna breeding programs.A draft genome sequence of beach pea was generated using a high-throughput next-generation sequencing platform,yielding 23.7 Gb of sequence from 79,929,868 filtered reads.A de novo genome assembly containing 68,731 scaffolds gave an N50 length of 10,272 bp and the assembled sequences totaled 365.6 Mb.A total of 35,448 SSRs,including 3574 compound SSRs,were identified and primer pairs for most of these SSRs were designed.Genome analysis identified 50,670 genes with mean coding sequence length 1042 bp.Phylogenetic analysis revealed highest sequence similarity with V.angularis,followed by V.radiata.Comparison with the V.angularis genome revealed 16,699 SNPs and 2253 InDels and comparison with the V.radiata genome revealed 17,538 SNPs and 2300 InDels.To our knowledge this is the first draft genome sequence of beach pea derived from an accession(ANBp-14-03)adapted locally in the Andaman and Nicobar Islands of India.The draft genome sequence may facilitate the genetic enhancement in cultivated Vigna species.

Integrating Culture-based Antibiotic Resistance Profiles with Whole-genome Sequencing Data for 11,087 Clinical Isolates

Emerging antibiotic resistance is a major global health threat. The analysis of nucleic acid sequences linked to susceptibility phenotypes facilitates the study of genetic antibiotic resistance determinants to inform molecular diagnostics and drug development. We collected genetic data (11,087 newly-sequenced whole genomes) and culture-based resistance profiles (10,991 out of the 11,087 isolates comprehensively tested against 22 antibiotics in total) of clinical isolates including 18 main species spanning a time period of 30 years. Species and drug specific resistance patterns were observed including increased resistance rates for Acinetobacter baumannii to carbapenems and for Escherichia coli to fluoroquinolones. Species-level pan-genomes were constructed to reflect the genetic repertoire of the respective species,including conserved essential genes and known resis-tance factors. Integrating phenotypes and genotypes through species-level pan-genomes allowed to infer gene–drug resistance associations using statistical testing. The isolate collection and the analysis results have been integrated into GEAR-base,a resource available for academic research use free of charge at https://gear-base.com.

JAX-CNV:A Whole-genome Sequencing-based Algorithm for Copy Number Detection at Clinical Grade Level

We aimed to develop a whole-genome sequencing(WGS)-based copy number variant(CNV)calling algorithm with the potential of replacing chromosomal microarray assay(CMA)for clinical diagnosis.JAX-CNV is thus developed for CNV detection from WGS data.The performance of this CNV calling algorithm was evaluated in a blinded manner on 31 samples and compared to the 112 CNVs reported by clinically validated CMAs for these 31 samples.The result showed that JAX-CNV recalled 100%of these CNVs.Besides,JAX-CNV identified an average of 30 CNVs per individual,representing an approximately seven-fold increase compared to calls of clinically validated CMAs.Experimental validation of 24 randomly selected CNVs showed one false positive,i.e.,a false discovery rate(FDR)of 4.17%.A robustness test on lowercoverage data revealed a 100%sensitivity for CNVs larger than 300 kb(the current threshold for College of American Pathologists)down to 10×coverage.For CNVs larger than 50 kb,sensitivities were 100%for coverages deeper than 20×,97%for 15×,and 95%for 10×.We developed a WGS-based CNV pipeline,including this newly developed CNV caller JAX-CNV,and found it capable of detecting CMA-reported CNVs at a sensitivity of 100%with about a FDR of 4%.We propose that JAX-CNV could be further examined in a multi-institutional study to justify the transition of first-tier genetic testing from CMAs to WGS.JAX-CNV is available at https://github.com/TheJacksonLaboratory/JAX-CNV.

Complete genome sequence of a Rodent Torque teno virus in Hainan Island, China and establishment of a real-time PCR for detecting Rodent Torque teno virus 3

Objective:To perform whole-genome sequencing and phylogenetic analysis of the local endemic strain of Rodent Torque teno virus (RoTTV), RoTTV3-HMU1, found in Rattus norvegicus, Haikou City, Hainan Province, and establish a SYBR Green I based real-time PCR detection assay for RoTTV3.Methods: Based on the high-throughput genome sequencing analysis, specific primers were designed and the whole genome sequence was amplified by PCR and Sanger sequencing. Specific detection primers were designed based on the conserved sequences of RoTTV3. The recombinant plasmid contained the whole genome of RoTTV3-HMU1 was constructed as a standard control. The experimental conditions were optimized and the real-time PCR detection assay of RoTTV3 was established.Results: The genomic sequence of RoTTV carried by Rattus norvegicus in Haikou City was successfully sequenced. Phylogenetic analysis indicated that the virus belongs to the RoTTV3 genotype. In this experiment, the real-time PCR detection method of RoTTV3 was established. The standard curve generated had a wide dynamic range from 1×(102-108) copies/μL, with a linear correlation (R2=1.000). The melting curve analysis using SYBR Green showed only one specific melting peak and no primer-dimmers represented. The detection limit was 100 copies/reaction.Discussion: This study was the first report of the RoTTV in Hainan Islands, and its phylogenetic analysis was of great significance to the origin and evolution of RoTTV. The RoTTV3 real-time PCR detection method established in this experiment has a high sensitivity and good specificity, which lays a technical foundation for the epidemiological investigation of RoTTV3.

Genotyping Characteristics of Human Fecal Escherichia coli and Their Association with Multidrug Resistance in Miyun District, Beijing

Objective To explore the genotyping characteristics of human fecal Escherichia coli(E. coli) and the relationships between antibiotic resistance genes(ARGs) and multidrug resistance(MDR) of E. coli in Miyun District, Beijing, an area with high incidence of infectious diarrheal cases but no related data.Methods Over a period of 3 years, 94 E. coli strains were isolated from fecal samples collected from Miyun District Hospital, a surveillance hospital of the National Pathogen Identification Network. The antibiotic susceptibility of the isolates was determined by the broth microdilution method. ARGs,multilocus sequence typing(MLST), and polymorphism trees were analyzed using whole-genome sequencing data(WGS).Results This study revealed that 68.09% of the isolates had MDR, prevalent and distributed in different clades, with a relatively high rate and low pathogenicity. There was no difference in MDR between the diarrheal(49/70) and healthy groups(15/24).Conclusion We developed a random forest(RF) prediction model of TEM.1 + baeR + mphA + mphB +QnrS1 + AAC.3-IId to identify MDR status, highlighting its potential for early resistance identification. The causes of MDR are likely mobile units transmitting the ARGs. In the future, we will continue to strengthen the monitoring of ARGs and MDR, and increase the number of strains to further verify the accuracy of the MDR markers.

Genome-Wide Dissection of Quan 9311A Breeding Process and Application Advantages

Germplasm resource innovation is a crucial factor for cultivar development,particularly within the context of hybrid rice breeding based on the three-line system.Quan 9311A,a cytoplasmic male sterile(CMS)line,has been successfully cultivated using rice restoration materials and extensively employed as a female parent in hybrid breeding program in China.This line was developed by crossing the CMS line Zhong 9A with a two-line restorer line 93-11,with the intention of eliminating the restoring ability of 93-11 while retaining the sterility gene WA352c from Zhong 9A.Quan 9311A effectively amalgamates the most favorable agronomic traits from both parental lines.In this study,the relationship between phenotypic characteristics and the known functional genes of Quan 9311A were analyzed using the rice genome navigation technology based on whole-genome sequencing.The findings revealed that Quan 9311A harbors multiple superior alleles from both 93-11 and Zhong 9A,providing exceptional agronomic traits that are unavailable in earlier CMS lines.Despite the removal of the fertility restorer gene Rf3 from 93-11,numerous chromosomal segments from 93-11 persist in the Quan 9311A genome.Furthermore,the hybrid rice Quanyousimiao(QYSM)and the restorer line Wushansimiao(WSSM)were used as examples to illustrate the important role of Quan 9311A as the female parent in heterosis.It was found that QYSM carries a great number of superior alleles,which accounts for its high grain yield and wide adaptability.These insights not only advanced the utilization of hybrid rice pairing groups but also provided guidance for future breeding endeavors.The study introduced innovative concepts to further integrate genomics with traditional breeding techniques.Ultimately,Quan 9311A signified a significant milestone in rice breeding technology,opening up novel avenues for hybrid rice development.