This paper presents an update on the content, accessibility and analytical tools of the EnteroBase platform for web-based pathogen genome analysis. EnteroBase provides manually curated databases of genome sequence data and associated metadata from currently >1.1 million bacterial isolates, more recently including Streptococcus spp. and Mycobacterium tuberculosis, in addition to Salmonella,Escherichia/Shigella,Clostridioides,Vibrio,Helicobacter,YersiniaandMoraxella. We have implemented the genome-based detection of antimicrobial resistance determinants and the new bubble plot graphical tool for visualizing bacterial genomic population structures, based on pre-computed hierarchical clusters. Access to data and analysis tools is provided through an enhanced graphical user interface and a new application programming interface (RESTful API). EnteroBase is now being developed and operated by an international consortium, to accelerate the development of the platform and ensure the longevity of the resources built. EnteroBase can be accessed at https://enterobase.warwick.ac.uk as well as https://enterobase.dsmz.de.

Trisomy of human chromosome 21 (T21) gives rise to Down syndrome (DS), the most frequent live-born autosomal aneuploidy. T21 triggers genome-wide transcriptomic alterations that result in multiple atypical phenotypes with highly variable penetrance and expressivity in individuals with DS. Many of these phenotypes, including atypical neurodevelopment, emerge prenatally. To enable in vitro analyses of the cellular and molecular mechanisms leading to the neurological alterations associated with T21, we created and characterized a panel of genomically diverse T21 and euploid induced pluripotent stem cells (iPSCs). We subsequently differentiated these iPSCs to generate a panel of neural progenitor cells (NPCs). Alongside characterizing genotype effects from T21, we found that T21 NPCs showed inter-individual variability in growth rates, oxidative stress, senescence characteristics, and gene and protein expression. Pathway enrichment analyses of T21 NPCs identified vesicular transport, DNA repair, and cellular response to stress pathways. These results demonstrate T21-associated variability at the cellular level and suggest that cell lines from individuals with DS should not solely be analyzed as a homogenous population. Examining large cohorts of genetically diverse samples may more fully reveal the effects of aneuploidy on transcriptomic and phenotypic characteristics in T21 cell types. A panel of genomically diverse T21 and euploid induced pluripotent stem cells (iPSCs) were created and subsequently differentiated into neural progenitor cells (NPCs). T21 NPCs showed reduced growth, increased oxidative stress, and inter-individual variability in gene and protein expression. This inter-individual variability suggests that studies with large cohorts of genetically diverse T21 samples may more fully reveal the effects of aneuploidy.

Salmonella enterica causes severe food-borne infections through contamination of the food supply chain. Its evolution has been associated with human activities, especially animal husbandry. Advances in intensive farming and global transportation have substantially reshaped the pig industry, but their impact on the evolution of associated zoonotic pathogens such as S. enterica remains unresolved. Here we investigated the population fluctuation, accumulation of antimicrobial resistance genes and international serovar Choleraesuis transmission of nine pig-enriched S. enterica populations comprising more than 9,000 genomes. Most changes were found to be attributable to the developments of the modern pig industry. All pig-enriched salmonellae experienced host transfers in pigs and/or population expansions over the past century, with pigs and pork having become the main sources of S. enterica transmissions to other hosts. Overall, our analysis revealed strong associations between the transmission of pig-enriched salmonellae and the global pork trade.

Abstract Background and aims Several non-invasive tests for detecting bladder cancer (BC) are commercially available and are based on detecting small panels of BC-associated mutations and/or methylation changes in urine DNA. However, it is not clear which type of biomarker is best, or if a combination of the two is needed. In this study we address this question by taking a 23-gene mutation panel (GALEAS™ Bladder, GB) and testing if adding a panel of methylation markers improves the sensitivity of BC detection. Methods Twenty-three methylation markers were assessed in urine DNA by bisulphite conversion, multiplex PCR, and next generation sequencing in 118 randomly selected haematuria patients with pre-existing GB data (56 BCs and 62 non-BCs), split into training and test sets. We also analysed an additional 16 GB false-negative urine DNAs. Results The methylation panel detected bladder cancer in haematuria patients with 69% sensitivity at 96% specificity (test set results, 95% CIs 52-87% and 80-99%, respectively). Corresponding sensitivity and specificity for GB were 92% and 89%. Methylation and mutation markers were highly concordant in urine, with all GB false-negative samples also negative for methylation markers. Conclusions and limitations Our data show that, with a comprehensive mutation panel, any gains from adding methylation markers are, at best, marginal. It is likely that low tumour content is the commonest cause of false-negative urine test results. Our study does have a limited sample size and other methylation markers might behave differently to the those studied here.

Treating plant bacterial diseases is notoriously difficult because of the lack of available antimicrobials. Pseudomonas syringae pathovar syringae (Pss) is a major pathogen of cherry (Prunus avium) causing bacterial canker of the stem, leaf and fruit, impacting productivity and leading to a loss of trees. In an attempt to find a treatment for this disease, naturally occurring bacteriophage (phage) that specifically target Pss is being investigated as a biocontrol strategy. However, before using them as a biocontrol treatment, it is important to both understand their efficacy in reducing the bacterial population and determine if the bacterial pathogens can evolve resistance to evade phage infection. To investigate this, killing curve assays of five MR phages targeting Pss showed that phage resistance rapidly emerges in vitro, even when using a cocktail of the five phages together. To gain insight to the changes occurring, Pss colonies were collected three times during a 66-h killing curve assay and separately, Pss and phage were also coevolved over 10 generations, enabling the measurement of genomic and fitness changes in bacterial populations. Pss evolved resistance to phages through modifications in lipopolysaccharide (LPS) synthesis pathways. Bacterial fitness (growth) and virulence were affected in only a few mutants. Deletion of LPS-associated genes suggested that LPS was the main target receptor for all five MR phages. Later generations of coevolved phages from the coevolution experiment were more potent at reducing the bacterial density and when used with wild-type phages could reduce the emergence of phage-resistant mutants. This study shows that understanding the genetic mechanisms of bacterial pathogen resistance to phages is important for helping to design a more effective approach to kill the bacteria while minimizing the opportunity for phage resistance to manifest.

Preterm birth is the leading cause of infant morbidity and mortality. There has been an interest in developing prostaglandin F2α (PGF2α) antagonists as a new treatment for preterm birth, although much of the rationale for their use is based on studies in rodents where PGF2α initiates labour by regressing the corpus luteum and reducing systemic progesterone concentrations. How PGF2α antagonism would act in humans who do not have a fall in systemic progesterone remains unclear. One possibility, in addition to an acute stimulation of contractions, is a direct alteration of the myometrial smooth muscle cell state towards a pro-labour phenotype. In this study, we developed an immortalised myometrial cell line, MYLA, derived from myometrial tissue obtained from a pregnant, non-labouring patient, as well as a novel class of PGF2α receptor (FP) antagonist. We verified the functionality of the cell line by stimulation with PGF2α, resulting in Gαq-specific coupling and Ca2+ release, which were inhibited by FP antagonism. Compared to four published FP receptor antagonists, the novel FP antagonist N582707 was the most potent compound [Fmax 7.67 ± 0.63 (IC50 21.26 nM), AUC 7.30 ± 0.32 (IC50 50.43 nM), and frequency of Ca2+ oscillations 7.66 ± 0.41 (IC50 22.15 nM)]. RNA-sequencing of the MYLA cell line at 1, 3, 6, 12, 24, and 48 h post PGF2α treatment revealed a transforming phenotype from a fibroblastic to smooth muscle mRNA profile. PGF2α treatment increased the expression of MYLK, CALD1, and CNN1 as well as the pro-labour genes OXTR, IL6, and IL11, which were inhibited by FP antagonism. Concomitant with the inhibition of a smooth muscle, pro-labour transition, FP antagonism increased the expression of the fibroblast marker genes DCN, FBLN1, and PDGFRA. Our findings suggest that in addition to the well-described acute contractile effect, PGF2α transforms myometrial smooth muscle cells from a myofibroblast to a smooth muscle, pro-labour–like state and that the novel compound N582707 has the potential for prophylactic use in preterm labour management beyond its use as an acute tocolytic drug.

Background: There is an unmet need for an accurate, validated, noninvasive test for diagnosing and monitoring bladder cancer (BC). Detection of BC-associated mutations in urinary DNA via targeted deep sequencing could meet this need. Objective: To test the ability of mutational analysis of urinary DNA to noninvasively detect BC within the context of haematuria investigations and non-muscle-invasive BC (NMIBC) surveillance. Design, setting, and participants: Capture-based ultra-deep sequencing was performed for 443 somatic mutations in 23 genes in 591 urine cell-pellet DNAs from haematuria clinic patients and 293 from NMIBC surveillance patients. Variant calling was optimised to minimise false positives using urine samples from 162 haematuria clinic patients without BC. Outcome measurements and statistical analysis: The sensitivity and specificity for BC diagnosis were determined. Results and limitations: Mutational analysis of urinary DNA detected 144 of the 165 haematuria patients diagnosed with incident BC from two independent cohorts, yielding overall sensitivity of 87.3% (95% confidence interval [CI] 81.2-92.0%) at specificity of 84.8% (95% CI 79.9-89.0%). The sensitivity was 97.4% for grade 3, 86.5% for grade 2, and 70.8% for grade 1 BC. Among NMIBC surveillance patients, 25 out of 29 recurrent BCs were detected, yielding sensitivity of 86.2% (95% CI 70.8-97.7%) at specificity of 62.5% (95% CI 56.1-68.0%); a positive urine mutation test in the absence of clinically detectable disease was associated with a 2.6-fold increase in the risk of future recurrence. The low number of recurrences in the NMIBC surveillance cohort and the lower sensitivity for detecting grade 1 pTa BC are limitations. Conclusions: Detection of mutations in a small panel of BC-associated genes could facilitate noninvasive BC testing , expedite haematuria investigations. Following further validation, the test could also play a role in NMIBC surveillance. Patient summary: Identification of alterations in genes that are frequently mutated in bladder cancer appears to be a promising strategy for detecting disease from urine samples and reducing reliance on examination of the bladder via a telescopic camera inserted through the urethra. (c) 2022 The Authors. Published by Elsevier B.V. on behalf of European Association of Urology. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4.0/).

Oculocutaneous albinism (OCA) is a rare disorder of pigment production. Affected individuals have variably decreased global pigmentation and visual-developmental changes that lead to low vision. OCA is notable for significant missing heritability, particularly among individuals with residual pigmentation. Tyrosinase (TYR) is the rate-limiting enzyme in melanin pigment biosynthesis and mutations that decrease enzyme function are one of the most common causes of OCA. We present the analysis of high-depth short-read TYR sequencing data for a cohort of 352 OCA probands, ∼50% of whom were previously sequenced without yielding a definitive diagnostic result. Our analysis identified 66 TYR single-nucleotide variants (SNVs) and small insertion/deletions (indels), 3 structural variants, and a rare haplotype comprised of two common frequency variants (p.Ser192Tyr and p.Arg402Gln) in cis-orientation, present in 149/352 OCA probands. We further describe a detailed analysis of the disease-causing haplotype, p.[Ser192Tyr; Arg402Gln] ("cis-YQ"). Haplotype analysis suggests that the cis-YQ allele arose by recombination and that multiple cis-YQ haplotypes are segregating in OCA-affected individuals and control populations. The cis-YQ allele is the most common disease-causing allele in our cohort, representing 19.1% (57/298) of TYR pathogenic alleles in individuals with type 1 (TYR-associated) OCA. Finally, among the 66 TYR variants, we found several additional alleles defined by a cis-oriented combination of minor, potentially hypomorph-producing alleles at common variant sites plus a second, rare pathogenic variant. Together, these results suggest that identification of phased variants for the full TYR locus are required for an exhaustive assessment for potentially disease-causing alleles.

Despite the knowledge that the soil–plant–microbiome nexus is shaped by interactions amongst its members, very little is known about how individual symbioses regulate this shaping. Even less is known about how the agriculturally important symbiosis of nitrogen-fixing rhizobia with legumes is impacted according to soil type, yet this knowledge is crucial if we are to harness or improve it. We asked how the plant, soil and microbiome are modulated by symbiosis between the model legume Medicago truncatula and different strains of Sinorhizobium meliloti or Sinorhizobium medicae whose nitrogen-fixing efficiency varies, in three distinct soil types that differ in nutrient fertility, to examine the role of the soil environment upon the plant–microbe interaction during nodulation. The outcome of symbiosis results in installment of a potentially beneficial microbiome that leads to increased nutrient uptake that is not simply proportional to soil nutrient abundance. A number of soil edaphic factors including Zn and Mo, and not just the classical N/P/K nutrients, group with microbial community changes, and alterations in the microbiome can be seen across different soil fertility types. Root endosphere emerged as the plant microhabitat more affected by this rhizobial efficiency-driven community reshaping, manifested by the accumulation of members of the phylum Actinobacteria. The plant in turn plays an active role in regulating its root community, including sanctioning low nitrogen efficiency rhizobial strains, leading to nodule senescence in particular plant–soil–rhizobia strain combinations. The microbiome–soil–rhizobial dynamic strongly influences plant nutrient uptake and growth, with the endosphere and rhizosphere shaped differentially according to plant–rhizobial interactions with strains that vary in nitrogen-fixing efficiency levels. These results open up the possibility to select inoculation partners best suited for plant, soil type and microbial community.

Mutations at specific hotspots in non-coding regions of ADGRG6, PLEKHS1, WDR74, TBC1D12 and LEPROTL1 frequently occur in bladder cancer (BC). These mutations could function as biomarkers for the non-invasive detection of BC but this remains largely unexplored. Massively-parallel sequencing of non-coding hotspots was applied to 884 urine cell pellet DNAs: 591 from haematuria clinic patients (165 BCs, 426 non-BCs) and 293 from non-muscle invasive BC surveillance patients (29 with recurrence). Urine samples from 142 non-BC haematuria clinic patients were used to optimise variant calling. Non-coding mutations are readily detectable in the urine of BC patients and undetectable, or present at much lower frequencies, in the absence of BC. The mutations can be used to detect incident BC with 66% sensitivity (95% CI 58–75) at 92% specificity (95% CI 88–95) and recurrent disease with 55% sensitivity (95% CI 36–74) at 85% specificity (95% CI 80–89%) using a 2% variant allele frequency threshold. In the NMIBC surveillance setting, the detection of non-coding mutations in urine in the absence of clinically detectable disease was associated with an increased relative risk of future recurrence (RR = 4.62 (95% CI 3.75–5.48)). As urinary biomarkers, non-coding hotspot mutations behave similarly to driver mutations in BC-associated genes and could be included in biomarker panels for BC detection.

Background: Down syndrome is associated with several comorbidities, including intellectual disability, growth restriction, and congenital heart defects. The prevalence of Down syndrome-associated comorbidities is highly variable, and intellectual disability, although fully penetrant, ranges from mild to severe. Understanding the basis of this interindividual variability might identify predictive biomarkers of in utero and postnatal outcomes that could be used as endpoints to test the efficacy of future therapeutic interventions. Objective: The main objective of this study was to examine if antenatal interindividual variability exists in mouse models of Down syndrome and whether applying statistical approaches to clinically relevant measurements (ie, the weights of the embryo, placenta, and brain) could define cutoffs that discriminate between subgroups of trisomic embryos. Study Design: Three commonly used mouse models of Down syndrome (Dp(16)1/Yey, Ts65Dn, and Ts1Cje) and a new model (Ts66Yah) were used in this study. Trisomic and euploid littermate embryos were used from each model with total numbers of 102 for Ts66Yah, 118 for Dp(16)1/Yey, 92 for Ts65Dn, and 126 for Ts1Cje. Placental, embryonic, and brain weights and volumes at embryonic day 18.5 were compared between genotypes in each model. K-mean clustering analysis was applied to embryonic and brain weights to identify severity classes in trisomic embryos, and brain and placental volumetric measurements were compared between genotypes and classes for each strain. In addition, Ts66Yah embryos were examined for malformations because embryonic phenotypes have never been examined in this model. Results: Reduced body and brain weights were present in Ts66Yah, Dp(16)1/Yey, and Ts65Dn embyos. Cluster analysis identified 2 severity classes in trisomic embryos-mild and severe-in all 4 models that were distinguishable using a putative embryonic weight cutoff of <0.5 standard deviation below the mean. Ts66Yah trisomic embryos develop congenital anomalies that are also found in humans with Down syndrome, including congenital heart defects and renal pelvis dilation. Conclusion: Statistical approaches applied to clinically relevant measurements revealed 2 classes of phenotypic severity in trisomic mouse models of Down syndrome. Analysis of severely affected trisomic animals may facilitate the identification of biomarkers and endpoints that can be used to prenatally predict outcomes and the efficacy of treatments.

Niemann–Pick disease type C1 (NPC1) is a rare, prematurely fatal lysosomal storage disorder which exhibits highly variable severity and disease progression as well as a wide-ranging age of onset, from perinatal stages to adulthood. This heterogeneity has made it difficult to obtain prompt diagnosis and to predict disease course. In addition, small NPC1 patient sample sizes have been a limiting factor in acquiring genome-wide transcriptome data. In this study, primary fibroblasts from an extensive cohort of 41 NPC1 patients were used to validate our previous findings that the lysosomal quantitative probe LysoTracker can be used as a predictor for age of onset and disease severity. We also examined the correlation between these clinical parameters and RNA expression data from primary fibroblasts and identified a set of genes that were significantly associated with lysosomal defects or age of onset, in particular neurological symptom onset. Hierarchical clustering showed that these genes exhibited distinct expression patterns among patient subgroups. This study is the first to collect transcriptomic data on such a large scale in correlation with clinical and cellular phenotypes, providing a rich genomic resource to address NPC1 clinical heterogeneity and discover potential biomarkers, disease modifiers, or therapeutic targets.

The definition of bacterial species is traditionally a taxonomic issue while bacterial populations are identified by population genetics. These assignments are species specific, and depend on the practitioner. Legacy multilocus sequence typing is commonly used to identify sequence types (STs) and clusters (ST Complexes). However, these approaches are not adequate for the millions of genomic sequences from bacterial pathogens that have been generated since 2012. EnteroBase (http://enterobase.warwick.ac.uk) automatically clusters core genome MLST allelic profiles into hierarchical clusters (HierCC) after assembling annotated draft genomes from short-read sequences. HierCC clusters span core sequence diversity from the species level down to individual transmission chains. Here we evaluate HierCC's ability to correctly assign 100 000 s of genomes to the species/subspecies and population levels for Salmonella, Escherichia, Clostridoides, Yersinia, Vibrio and Streptococcus. HierCC assignments were more consistent with maximum-likelihood super-trees of core SNPs or presence/absence of accessory genes than classical taxonomic assignments or 95% ANI. However, neither HierCC nor ANI were uniformly consistent with classical taxonomy of Streptococcus. HierCC was also consistent with legacy eBGs/ST Complexes in Salmonella or Escherichia and with O serogroups in Salmonella. Thus, EnteroBase HierCC supports the automated identification of and assignment to species/subspecies and populations for multiple genera.This article is part of a discussion meeting issue ‘Genomic population structures of microbial pathogens’.

The definition of bacterial species is traditionally a taxonomic issue while bacterial populations are identified by population genetics. These assignments are species specific, and depend on the practitioner. Legacy multilocus sequence typing is commonly used to identify sequence types (STs) and clusters (ST Complexes). However, these approaches are not adequate for the millions of genomic sequences from bacterial pathogens that have been generated since 2012. EnteroBase ( http://enterobase.warwick.ac.uk ) automatically clusters core genome MLST allelic profiles into hierarchical clusters (HierCC) after assembling annotated draft genomes from short-read sequences. HierCC clusters span core sequence diversity from the species level down to individual transmission chains. Here we evaluate HierCC's ability to correctly assign 100 000s of genomes to the species/subspecies and population levels for Salmonella, Escherichia, Clostridoides, Yersinia, Vibrio and Streptococcus . HierCC assignments were more consistent with maximum-likelihood super-trees of core SNPs or presence/absence of accessory genes than classical taxonomic assignments or 95% ANI. However, neither HierCC nor ANI were uniformly consistent with classical taxonomy of Streptococcus. HierCC was also consistent with legacy eBGs/ST Complexes in Salmonella or Escherichia and with O serogroups in Salmonella . Thus, EnteroBase HierCC supports the automated identification of and assignment to species/subspecies and populations for multiple genera. This article is part of a discussion meeting issue ‘Genomic population structures of microbial pathogens’.

The definition of bacterial species is traditionally a taxonomic issue while bacterial populations are identified by population genetics. These assignments are species specific, and depend on the practitioner. Legacy multilocus sequence typing is commonly used to identify sequence types (STs) and clusters (ST Complexes). However, these approaches are not adequate for the millions of genomic sequences from bacterial pathogens that have been generated since 2012. EnteroBase ( http://enterobase.warwick.ac.uk ) automatically clusters core genome MLST allelic profiles into hierarchical clusters (HierCC) after assembling annotated draft genomes from short read sequences. HierCC clusters span core sequence diversity from the species level down to individual transmission chains. Here we evaluate HierCC’s ability to correctly assign 100,000s of genomes to the species/subspecies and population levels for Salmonella, Escherichia, Clostridoides, Yersinia, Vibrio and Streptococcus . HierCC assignments were more consistent with maximum-likelihood super-trees of core SNPs or presence/absence of accessory genes than classical taxonomic assignments or 95% ANI. However, neither HierCC nor ANI were uniformly consistent with classical taxonomy of Streptococcus. HierCC was also consistent with legacy eBGs/ST Complexes in Salmonella or Escherichia and with O serogroups in Salmonella . Thus, EnteroBase HierCC supports the automated identification of and assignment to species/subspecies and populations for multiple genera.

Legumes house nitrogen-fixing endosymbiotic rhizobia in specialized polyploid cells within root nodules, which undergo tightly regulated metabolic activity. By carrying out expression analysis of transcripts over time in Medicago truncatula nodules, we found that the circadian clock enables coordinated control of metabolic and regulatory processes linked to nitrogen fixation. This involves the circadian clock-associated transcription factor LATE ELONGATED HYPOCOTYL (LHY), with lhy mutants being affected in nodulation. Rhythmic transcripts in root nodules include a subset of nodule-specific cysteine-rich peptides (NCRs) that have the LHY-bound conserved evening element in their promoters. Until now, studies have suggested that NCRs act to regulate bacteroid differentiation and keep the rhizobial population in check. However, these conclusions came from the study of a few members of this very large gene family that has complex diversified spatio-temporal expression. We suggest that rhythmic expression of NCRs may be important for temporal coordination of bacterial activity with the rhythms of the plant host, in order to ensure optimal symbiosis.

Niemann-Pick C1 disease (NPC1) is a rare, fatal neurodegenerative disease caused by mutations in NPC1, which encodes the lysosomal cholesterol transport protein NPC1. Disease pathology involves lysosomal accumulation of cholesterol and lipids, leading to neurological and visceral complications. Targeting the central nervous system (CNS) from systemic circulation complicates treatment of neurological diseases with gene transfer techniques. Selected and engineered capsids, for example, adeno-associated virus (AAV)-PHP.B facilitate peripheral-to-CNS transfer and hence greater CNS transduction than parental predecessors. We report that systemic delivery to Npc1 m1N/m1N mice using an AAV-PHP.B vector ubiquitously expressing NPC1 led to greater disease amelioration than an otherwise identical AAV9 vector. In addition, viral copy number and biodistribution of GFP-expressing reporters showed that AAV-PHP.B achieved more efficient, albeit variable, CNS transduction than AAV9 in Npc1 m1N/m1N mice. This variability was associated with segregation of two alleles of the putative AAV-PHP.B receptor Ly6a in Npc1 m1N/m1N mice. Our data suggest that robust improvements in NPC1 disease phenotypes occur even with modest CNS transduction and that improved neurotrophic capsids have the potential for superior NPC1 AAV gene therapy vectors.

Here, we report an improved and complete genome sequence of Sinorhizobium (Ensifer) meliloti strain WSM1022, a microsymbiont of Medicago species, revealing its tripartite structure. This improved genome sequence was generated combining Illumina and Oxford nanopore sequencing technologies to better understand the symbiotic properties of the bacterium. The 6.75 Mb WSM1022 genome consists of three scaffolds, corresponding to a chromosome (3.70 Mb) and the pSymA (1.38 Mb) and pSymB (1.66 Mb) megaplasmids. The assembly has an average GC content of 62.2% and a mean coverage of 77X. Genome annotation of WSM1022 predicted 6058 protein coding sequences (CDSs), 202 pseudogenes, 9 rRNAs (3 each of 5S, 16S, and 23S), 55 tRNAs, and 4 ncRNAs. We compared the genome of WSM1022 to two other rhizobial strains, closely related Sinorhizobium (Ensifer) meliloti Sm1021 and Sinorhizobium (Ensifer) medicae WSM419. Both WSM1022 and WSM419 species are high-efficiency rhizobial strains when in symbiosis with Medicago truncatula, whereas Sm1021 is ineffective. Our findings report significant genomic differences across the three strains with some similarities between the meliloti strains and some others between the high efficiency strains WSM1022 and WSM419. The addition of this high-quality rhizobial genome sequence in conjunction with comparative analyses will help to unravel the features that make a rhizobial symbiont highly efficient for nitrogen fixation.

Legumes house nitrogen-fixing endosymbiotic rhizobia in specialized polyploid cells within root nodules, which are factories of metabolic activity. We discovered that the circadian clock-associated transcriptional factor LATE ELONGATED HYPOCOTYL (LHY) affects nodulation in Medicago truncatula . By carrying out expression analysis of transcripts over time in nodules we found that the clock enables coordinated control of metabolic and regulatory processes linked to nitrogen fixation. Rhythmic transcripts in root nodules include a subset of Nodule-specific Cysteine Rich peptides (NCRs) that have the LHY-bound conserved Evening Element in their promoters. Until now, studies have suggested that NCRs act to regulate bacteroid differentiation and keep the rhizobial population in check. However, these conclusions came from the study of a few members of this very large gene family that has complex diversified spatio-temporal expression. We suggest that rhythmic expression of NCRs may be important for temporal coordination of bacterial activity with the rhythms of the plant host, in order to ensure optimal symbiosis. Highlights The circadian clock-associated transcriptional factor LATE ELONGATED HYPOCOTYL (LHY) impacts on successful Medicago truncatula -rhizobial symbiosis The plant clock coordinates rhythmic patterns of metabolic and regulatory activity in nodules and drives rhythmic expression of a subset of Nodule-specific Cysteine Rich (NCR) genes. Rhythmic expression of NCRs may be important for temporal coordination of bacterial activity with plant host rhythms to ensure optimal symbiosis.

Accumulating evidence implies the utility of DNA-based urine biomarkers for initial detection of bladder cancer (BC) and surveillance of non-muscle-invasive BC [1, 2]. We have previously described gene panels with utility for these indications, identifying UBC-associated mutations in 96% of all BCs, such that the associated urine test is not reliant on the initial identification of mutations in primary tumour tissue [1]. By contrast, the utility of urine as a liquid biopsy for the surveillance of patients with muscle-invasive BC (MIBC) treated by bladder preservation (radiotherapy ± chemotherapy) remains understudied; one previous publication describes microsatellite analysis of urinary DNA to detect bladder recurrences in five out of six radiotherapy patients [3]. We undertook a pilot study to evaluate whether measuring common BC-associated mutations in urinary DNA can contribute to the monitoring of treatment responses in patients with organ-confined MIBC treated with curative intent. Our objectives were to: (i) investigate the potential of urine DNA analysis before, during and after treatment as indicators of treatment response; (ii) investigate the prognostic value of an absence of detectable genomic alterations post treatment; and (iii) compare two orthogonal methodologies for detecting variants in urinary DNA (capture and Illumina sequencing vs PCR and Ion Torrent sequencing). As part of the TUXEDO trial (a phase I/II feasibility study of cetuximab plus 5FU and mitomycin C or cisplatin with concomitant radiotherapy in patients with organ-confined MIBC; ethics approval 11/LO/1313, protocol at https://www.birmingham.ac.uk/research/crctu/trials/tuxedo/index.aspx), urine samples were collected from patients with MIBC before, during and after treatment with chemoradiotherapy. Briefly, urine samples (50 mL) were collected prior to treatment on the first day of weeks −1 to +7 (treatment completion) and at one post-treatment visit using urine preservation tubes (Norgenbiotek.com). Urine samples were centrifuged for 10 min at 2000g and DNA extracted from the pellet using the QuickDNA kit (Zymoresearch.com) and quantitated by Qubit. Capture-based libraries were prepared using 25 ng urine cell pellett DNA (cpDNA) and Nonacus Cell3Target (Nonacus.com). Target enrichment was via a custom panel covering c.10 kb and including hotspots/regions of 29 genes: coding regions of 23 genes plus the TERT promotor and an additional five non-coding mutation hotspots, as previously defined by large-scale tumour sequencing [1, 4]. Libraries were sequenced on an Illumina Nextseq system (2 × 150 bp); reads were aligned to hg19 genome version using BWA. Variant allele frequencies (VAFs) were extracted using the bam-readcount tool for the disease-associated single-nucleotide variants (SNVs) identified previously [1, 4]. We considered a 0.5% VAF to be the limit of detection for SNVs [5], and a 1% VAF to be the limit of quantitation. We report quantitative changes in the VAFs of urinary SNVs during treatment for all SNVs that exceeded 1% VAF at any time in each patient. Average raw and consensus read depths were 27 100× and 3000×, respectively. Multiplex-PCR-based libraries were prepared using AmpliseqHD reagents (ThermoFisher) and workflow. Two panels of target-specific primers and 2 × 20 ng urine cpDNA were used to amplify the same target regions as for the capture-based approach. The libraries were sequenced using 540 chips on an S5 Ion Torrent system (2 × 100 bp; ThermoFisher). Alignments, consensus-building and variant calling were performed using Ion Reporter software. Average raw and consensus read depths were 79 300× and 5500×, respectively. We excluded AmpliseqHD data for the TERT promoter as this GC-rich amplicon did not give sufficient consensus reads for reliable variant calling. In this way, common UBC-associated mutations were determined longitudinally in six patients. For one patient, no mutations were detected at any time point. For coding and TERT promoter mutations, cpDNA of four out of five patients contained high levels of tumour DNA (VAFs 4–20%) at baseline (post-transurethral resection, pre-chemoradiotherapy). VAFs in cpDNA decreased to lower levels in all patients by the end of treatment (Fig. 1). In patient A, multiple mutations in the TERT promoter were detected at >20% VAF at baseline. The unusual co-occurrence of the 242/243 and 250 TERT mutations was confirmed by Sanger sequencing (data not shown). These mutations were detected at higher VAFs after 1 week of cetuximab-loading and after 1 week of radiotherapy, then decreased rapidly to approximately 5% VAF, remained clearly detectable through the later stages of treatment, and were present at 1.4% VAF after treatment completion. Patient A relapsed with local recurrence (grade/stage unknown) 7 months later. In patient B, TERT 228A and FGFR3 S249C mutations were present at baseline; both were undetectable post-treatment. Patient B remained disease-free 16 months post-treatment. In patient C, TERT and TP53 mutations were present at baseline and, despite showing a downward trend, remained detectable at 1.7% VAF after treatment. Patient C was diagnosed with malignant ascites 3 months post-treatment. In patient D, TERT and TP53 mutations were present at baseline, dropped rapidly during treatment, and were undetectable after completion of treatment. Patient D was diagnosed with local recurrence (G3pT1) 5 months post-treatment. In patient E, a TERT promoter mutation was present at low VAF at baseline; this mutation did not show a clear trend over time and remained detectable at most time points. Patient E was diagnosed with local recurrence (G3pT1) 9 months post-treatment. PCR-based library preparation (AmpliseqHD) combined with Ion Torrent sequencing verified Illumina-based mutation detection and quantitation in cpDNA, except for the TERT promoter which amplified poorly (data not shown). VAFs measured by the two methods correlated well (r2 = 0.96), and AmpliseqHD confirmed 84%, 94% and 98% of SNVs detected by capture-based sequencing at ≥0.5%, 1% and 2% VAF, respectively. Copy number profiles (a by-product of off-target reads from capture-based target enrichment) for all cpDNA were inspected manually; copy number variant levels mirrored SNV levels (data not shown). In summary, two out of the four patients who relapsed (three local, one distant, 3–9 months after completing treatment) had undetectable urinary VAFs on treatment completion. This finding is particularly surprising for the two out of three bladder recurrences with undetectable urinary VAFs on treatment completion given that, in other cancer settings, the ‘clearance of mutations’ in liquid biopsy samples is associated with significantly improved outcomes [6]. The corollary is that two out of the three patients with detectable mutations on treatment completion experienced relapse within 7 months. Notwithstanding, we suggest that urine-based liquid biopsy monitoring of post-radiotherapy MIBC patients remains challenging, and should be combined with plasma ctDNA monitoring [7], or primary tumour tissue sequencing (to permit personalized urinary liquid biopsies with much lower detection thresholds [8]), or both. Methodologically, both targeted capture-based and PCR-based library preparation and next-generation sequencing can be used to identify common BC-associated mutations in urinary cpDNA. These pilot data suggest the need for further liquid biopsy research in this specific MIBC setting. The authors thank Katie Marquis, Florence Pethick and Giorgio Pea from Thermo Fisher UK, Nonacus Limited, and West Midlands Regional Genetics Laboratory. The liquid biopsy work was funded by a Cancer Research UK Early Detection Committee – CRUK-OHSU Spark Award (C16909/A27035). The TUXEDO trial was funded by Cancer Research UK (CRUK/09/021) and cetuximab was supplied by Merck Serono Ltd. Timur Mitin: UpToDate, Inc (royalties for chapter authorship), Novocure (study grant and advisory board), AstraZeneca (advisory board). Richard T. Bryan: Olympus Medical Systems (advisory board), Janssen (advisory board), UroGen Pharma (research grant), QED Therapeutics (research grant), Nonacus Limited (advisory board). Douglas G. Ward: Nonacus Limited (advisory board). The liquid biopsy work was funded by a Cancer Research UK Early Detection Committee – CRUK-OHSU Spark Award (C16909/A27035). The TUXEDO trial was funded by Cancer Research UK (CRUK/09/021) and cetuximab was supplied by Merck Serono Ltd.