Partial Genome Research Articles

Identical Viral Genetic Sequence Found in Black Flies (Simuliumbivittatum) and the Equine Index Case of the 2006 U.S. Vesicular Stomatitis Outbreak.

In 2006, vesicular stomatitis New Jersey virus (VSNJV) caused outbreaks in Wyoming (WY) horses and cattle after overwintering in 2004 and 2005. Within two weeks of the outbreak onset, 12,203 biting flies and 194 grasshoppers were collected near three equine-positive premises in Natrona County, WY. Insects were identified to the species level and tested by RT-qPCR for VSNJV polymerase (L) and phosphoprotein (P) gene RNA. Collected dipterans known to be competent for VSV transmission included Simulium black flies and Culicoides biting midges. VSNJV L and P RNA was detected in two pools of female Simulium bivittatum and subjected to partial genome sequencing. Phylogenetic analysis based on the hypervariable region of the P gene from black flies showed 100% identity to the isolate obtained from the index horse case on the same premises. This is the first report of VSNJV in S. bivittatum in WY and the first field evidence of possible VSV maintenance in black fly populations during an outbreak.

'Candidatus Xiphinematincola pachtaicus' gen. nov., sp. nov., an endosymbiotic bacterium associated with nematode species of the genus Xiphinema (Nematoda, Longidoridae).

An intracellular bacterium, strain IAST, was observed to infect several species of the plant-parasitic nematode genus Xiphinema (Xiphinema astaregiense, Xiphinema incertum, Xiphinema madeirense, Xiphinema pachtaicum, Xiphinema parapachydermum and Xiphinema vallense). The bacterium could not be recovered on axenic medium. The 16S rRNA gene sequence of IAST was found to be new, being related to the family Burkholderiaceae, class Betaproteobacteria. Fungal endosymbionts Mycoavidus cysteinexigens B1-EBT (92.9 % sequence identity) and ‘Candidatus Glomeribacter gigasporarum’ BEG34 (89.8 % identity) are the closest taxa and form a separate phylogenetic clade inside Burkholderiaceae. Other genes (atpD, lepA and recA) also separated this species from its closest relatives using a multilocus sequence analysis approach. These genes were obtained using a partial genome of this bacterium. The localization of the bacterium (via light and fluorescence in situ hybridization microscopy) is in the X. pachtaicum females clustered around the developing oocytes, primarily found embedded inside the epithelial wall cells of the ovaries, from where they are dispersed in the intestine. Transmission electron microscopy (TEM) observations supported the presence of bacteria inside the nematode body, where they occupy ovaries and occur inside the intestinal epithelium. Ultrastructural analysis of the bacterium showed cells that appear as mostly irregular, slightly curved rods with rounded ends, 0.8–1.2 µm wide and 2.5–6.0 µm long, possessing a typical Gram-negative cell wall. The peptidoglycan layer is, however, evident only occasionally and not detectable by TEM in most cells. Another irregularly occurring shell surrounding the endosymbiont cells or the cell clusters was also revealed, probably originating from the host cell membrane. Flagella or spore-like cells do not occur and the nucleoid is diffusely distributed throughout the cell. This endosymbiont is transmitted vertically through nematode generations. These results support the proposal of IAST as a new species, although its obligate intracellular and obligate endosymbiont nature prevented isolation of a definitive type strain. Strain IAST is therefore proposed as representing ‘Candidatus Xiphinematincola pachtaicus’ gen. nov., sp. nov.

Molecular identification of Haemaphysalis sulcata (Acari: Ixodidae) larval stages collected using the Berlese funnel in Northern Iran

Molecular detection techniques based on conventional PCR and sequencing of the partial genome of living organisms are considered an important tool for identification. BLASTn and comparison of evolutionary relationships between taxa are the next analysis steps on sequences. The construction of a phylogenetic tree is done using genetic distance difference; nucleotide substitution models and comparison with the outgroup. In the present study, two samples of tick larvae were collected in Mirafzal forest area (36°07'39.0N 53°35'45.0E) located in Mazandaran province, northern Iran using the Berlese funnel. Tick samples were initially identified using a generic identification key (Bregetova et al. 1955) and in order to determine specific identification of species, PCR of partial internal transcribed spacer 2 (ITS2) gene and Sanger sequencing were performed. Morphological results showed that tick samples belonged to Haemaphysalis genus because they had a relatively short capitulum, no eyes with festoons. DNA extraction, PCR amplification and sequencing of a partial fragment (ca. 1400-bp) ITS2 gene of tick sample were done, successfully. The results of BLASTn showed that the larvae belonged to the species Haemaphysalis sulcata. A nucleotide DNA sequence of ITS2 was submitted to GenBank under the accession number MW929218. The molecular technique of this study is recommended to identify immature and dead tick samples that cannot be reared until the adult stage. The present study was the first report on the identification of H. sulcata larvae isolated from the Berlese funnel. The result of this study will help to better understand the biology of this tick and the presence of immature larval stages with questing behaviour in the soil environment.

RT-PCR based SARS-CoV-2 variant screening assays require careful quality control.

BackgroundDistinctive genotypes of SARS-CoV-2 have emerged that are or may be associated with increased transmission, pathogenicity, and/or antibody escape. In many countries, clinical and diagnostic laboratories are under mandate to identify and report these so-called variants of concern (VOC).ObjectivesWe used an external quality assessment scheme to determine the scope, accuracy, and reliability of laboratories using various molecular diagnostic assays to identify current VOC (03 March 2021).Study designParticipant laboratories were sent the same five patient-derived samples and were asked to provide their variant detection methods, variant detection results and interpretation of results.ResultsTwenty-five laboratories reported a range of RT-qPCR-based assays to identify specific variations in the SARS-CoV-2 spike protein that are characteristic of three VOC lineages. Laboratories that detected VOC-associated nucleotide mutations at four specific sites had the highest ratio of correct classification. Low template copy number and additional variation in target regions resulted in loss of confidence and accuracy in sample classification.ConclusionsMelting-curve-based assays to identify genomic variants are less time-consuming and require less bioinformatic analysis compared to partial or whole genome sequencing. However, our results suggest that correct classification of a given genotype/lineage (e.g., a VOC) relies on the ability to detect more than one variant site, adequate template in the sample (i.e., relatively high viral load/copy number) and results may be unclear in certain samples with additional genetic variations. These initial results suggest that some diagnostic laboratories may require additional training to interpret and report complex genetic information about a dynamic emerging virus.

Clinical evaluation of a Hepatitis C Virus whole-genome sequencing pipeline for genotyping and resistance testing

ObjectivesWe sought to evaluate clinically a hepatitis C virus (HCV) whole-genome, next-generation sequencing (NGS) pipeline that is agnostic to viral genotype. MethodsPerformance of the NGS pipeline was assessed through comparison of results with Sanger sequencing (SS) of partial HCV genomes. ResultsThere was 98.7% (376/381) concordance for viral subtype between SS and NGS. The positive and negative per cent agreements for determination of resistance-associated substitutions were 97.8% (95% CI 92.5–99.4%) and 99.9% (95% CI 99.5–100.0%), respectively. The NGS pipeline was also able to detect novel subtypes, mixtures, recombinants, transiently occurring resistance mutations and distinguish re-infection with the same subtype from relapse. DiscussionParticular scenarios where NGS may be used include settings without universal access to pan-genotypic antiviral regimens, those infected with a ‘rare’ subtype or who have been failed by first-line therapy, and in cases of suspected re-infection.

Illuminating the Plant Rhabdovirus Landscape through Metatranscriptomics Data.

Rhabdoviruses infect a large number of plant species and cause significant crop diseases. They have a negative-sense, single-stranded unsegmented or bisegmented RNA genome. The number of plant-associated rhabdovirid sequences has grown in the last few years in concert with the extensive use of high-throughput sequencing platforms. Here, we report the discovery of 27 novel rhabdovirus genomes associated with 25 different host plant species and one insect, which were hidden in public databases. These viral sequences were identified through homology searches in more than 3000 plant and insect transcriptomes from the National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA) using known plant rhabdovirus sequences as the query. The identification, assembly and curation of raw SRA reads resulted in sixteen viral genome sequences with full-length coding regions and ten partial genomes. Highlights of the obtained sequences include viruses with unique and novel genome organizations among known plant rhabdoviruses. Phylogenetic analysis showed that thirteen of the novel viruses were related to cytorhabdoviruses, one to alphanucleorhabdoviruses, five to betanucleorhabdoviruses, one to dichorhaviruses and seven to varicosaviruses. These findings resulted in the most complete phylogeny of plant rhabdoviruses to date and shed new light on the phylogenetic relationships and evolutionary landscape of this group of plant viruses. Furthermore, this study provided additional evidence for the complexity and diversity of plant rhabdovirus genomes and demonstrated that analyzing SRA public data provides an invaluable tool to accelerate virus discovery, gain evolutionary insights and refine virus taxonomy.

Microbial metagenomic approach uncovers the first rabbit haemorrhagic disease virus genome in Sub-Saharan Africa

Rabbit Haemorrhagic Disease (RHD) causes high morbidity and mortality in rabbits and hares. Here, we report the first genomic characterization of lagovirus GI.2 virus in domestic rabbits from sub-Saharan Africa. We used an unbiased microbial metagenomic Next Generation Sequencing (mNGS) approach to diagnose the pathogen causing the suspected outbreak of RHD in Ibadan, Nigeria. The liver, spleen, and lung samples of five rabbits from an outbreak in 2 farms were analyzed. The mNGS revealed one full and two partial RHDV2 genomes on both farms. Phylogenetic analysis showed close clustering with RHDV2 lineages from Europe (98.6% similarity with RHDV2 in the Netherlands, and 99.1 to 100% identity with RHDV2 in Germany), suggesting potential importation. Subsequently, all the samples were confirmed by RHDV virus-specific RT-PCR targeting the VP60 gene with the expected band size of 398 bp for the five rabbits sampled. Our findings highlight the need for increased genomic surveillance of RHDV2 to track its origin, understand its diversity and to inform public health policy in Nigeria, and Sub-Saharan Africa.

Isolation and characterization of microsatellite markers from Garcinia indica and cross species amplification

Garcinia indica popularly known as ‘Kokum’ or Murugalu”, is a medium-sized evergreen tree found in the western-ghats of India. This tree species is highly exploited to produce anti-obesity drugs and culinary purposes. Its population is threatened by overexploitation and loss of habitat. The development of microsatellite markers would help in understanding the genetic structure and further to develop appropriate conservation strategies. In this study, using next generation sequencing platform Illumina Hiseq 2000, we have sequenced the partial genome of G. indica and identified 3725 microsatellites. Forty-eight microsatellite markers were analyzed using 30 accessions. Polymorphism information content (PIC) values ranged from 0.718 to 0.968 with a mean value of 0.922. Allele per locus ranged from 3 to 33 per locus. The probability of identity values ranged from 0.00329 to 0.30489. Cross-species amplification SSR primers in the related species showed a moderate transferability from 12.5 % (for G. morella) to 18.7%(for G. gummigutta)

Isolation and characterization of microsatellite markers from Garcinia indica and cross species amplification

Garcinia indica popularly known as ‘Kokum’ or Murugalu”, is a medium-sized evergreen tree found in the western-ghats of India. This tree species is highly exploited to produce anti-obesity drugs and culinary purposes. Its population is threatened by overexploitation and loss of habitat. The development of microsatellite markers would help in understanding the genetic structure and further to develop appropriate conservation strategies. In this study, using next generation sequencing platform Illumina Hiseq 2000, we have sequenced the partial genome of G. indica and identified 3725 microsatellites. Forty-eight microsatellite markers were analyzed using 30 accessions. Polymorphism information content (PIC) values ranged from 0.718 to 0.968 with a mean value of 0.922. Allele per locus ranged from 3 to 33 per locus. The probability of identity values ranged from 0.00329 to 0.30489. Cross-species amplification SSR primers in the related species showed a moderate transferability from 12.5 % (for G. morella) to 18.7%(for G. gummigutta)

Prevalence of anaplasmosis in cattle from Chattogram Division of Bangladesh

Bovine anaplasmosis is an important haemoparasitic disease of farm animals associated with significant economic loss. The current study was designed to determine the prevalence and associated risk factors and molecular characterization of Anaplasma species. A total of 1680 blood (crossbred=455, local=1225) from cattle of selected hilly, coastal and plain areas of Chattogram Division. Bangladesh. The conventional microscopic examination using the Giemsa staining technique was considered to examine the samples. A total of 50 randomly selected blood samples (apparently positive as determined by microscopy) were tested using polymerase chain reaction (PCR) to confirm the disease. Partial genome sequencing (based on 16S rRNA gene) and phylogenetic analyses were performed. Results demonstrated that a total of 8.21% of cattle (n=1680) were positive for Anaplama marginale infection. The prevalence of anaplasmosis in the hilly area was 9.33% followed by coastal area (9.00%) and plain area (5.83%). The prevalence of Anaplasma spp. was higher (P>0.05) in crossbred compared to indigenous cattle. The infection was significantly higher (P

Metagenome-assembled genome (MAG) of Oceancaulis alexandrii NP7 isolated from Mediterranean Sea polluted marine sediments and its bioremediation potential.

Oceanicaulis alexandrii strain NP7 is a marine bacterium which belongs to the Hyphomonadaceae family and was isolated from sediments highly contaminated with metals and polycyclic aromatic hydrocarbons released for decades by industrial activities in the Gulf of Naples (Mediterranean Sea). Here, we report the partial genome sequence and annotation of O. alexandrii strain NP7 that contains a chromosome of 2,954,327 bp and encodes for 2914 predicted coding sequences (CDSs) and 44 RNA-encoding genes. Although the presence of some CDSs for genes involved in hydrocarbon degradation processes (e.g., alkB) have already been described in the literature associated with the Oceanicaulis, this is the first time that more than 100 genes involved in metal detoxification processes and hydrocarbon degradation are reported belonging to this genus. The presence of a heterogeneous set of genes involved in stress response, hydrocarbon degradation, heavy metal resistance, and detoxification suggests a possible role for O. alexandrii NP7 in the bioremediation of these highly contaminated marine sediments.

Genome Warehouse: A Public Repository Housing Genome-scale Data

The Genome Warehouse (GWH) is a public repository housing genome assembly data for a wide range of species and delivering a series of web services for genome data submission, storage, release, and sharing. As one of the core resources in the National Genomics Data Center (NGDC), part of the China National Center for Bioinformation (CNCB; https://ngdc.cncb.ac.cn), GWH accepts both full and partial (chloroplast, mitochondrion, and plasmid) genome sequences with different assembly levels, as well as an update of existing genome assemblies. For each assembly, GWH collects detailed genome-related metadata of biological project, biological sample, and genome assembly, in addition to genome sequence and annotation. To archive high-quality genome sequences and annotations, GWH is equipped with a uniform and standardized procedure for quality control. Besides basic browse and search functionalities, all released genome sequences and annotations can be visualized with JBrowse. By May 21, 2021, GWH has received 19,124 direct submissions covering a diversity of 1108 species and has released 8772 of them. Collectively, GWH serves as an important resource for genome-scale data management and provides free and publicly accessible data to support research activities throughout the world. GWH is publicly accessible at https://ngdc.cncb.ac.cn/gwh.

Predicting Antimicrobial Resistance Using Partial Genome Alignments.

ABSTRACTAntimicrobial resistance (AMR) is an important global health threat that impacts millions of people worldwide each year. Developing methods that can detect and predict AMR phenotypes can help to mitigate the spread of AMR by informing clinical decision making and appropriate mitigation strategies. Many bioinformatic methods have been developed for predicting AMR phenotypes from whole-genome sequences and AMR genes, but recent studies have indicated that predictions can be made from incomplete genome sequence data. In order to more systematically understand this, we built random forest-based machine learning classifiers for predicting susceptible and resistant phenotypes for Klebsiella pneumoniae (1,640 strains), Mycobacterium tuberculosis (2,497 strains), and Salmonella enterica (1,981 strains). We started by building models from alignments that were based on a reference chromosome for each species. We then subsampled each chromosomal alignment and built models for the resulting subalignments, finding that very small regions, representing approximately 0.1 to 0.2% of the chromosome, are predictive. In K. pneumoniae, M. tuberculosis, and S. enterica, the subalignments are able to predict multiple AMR phenotypes with at least 70% accuracy, even though most do not encode an AMR-related function. We used these models to identify regions of the chromosome with high and low predictive signals. Finally, subalignments that retain high accuracy across larger phylogenetic distances were examined in greater detail, revealing genes and intergenic regions with potential links to AMR, virulence, transport, and survival under stress conditions.IMPORTANCE Antimicrobial resistance causes thousands of deaths annually worldwide. Understanding the regions of the genome that are involved in antimicrobial resistance is important for developing mitigation strategies and preventing transmission. Machine learning models are capable of predicting antimicrobial resistance phenotypes from bacterial genome sequence data by identifying resistance genes, mutations, and other correlated features. They are also capable of implicating regions of the genome that have not been previously characterized as being involved in resistance. In this study, we generated global chromosomal alignments for Klebsiella pneumoniae, Mycobacterium tuberculosis, and Salmonella enterica and systematically searched them for small conserved regions of the genome that enable the prediction of antimicrobial resistance phenotypes. In addition to known antimicrobial resistance genes, this analysis identified genes involved in virulence and transport functions, as well as many genes with no previous implication in antimicrobial resistance.

High-Quality Genome Reconstruction of Candida albicans CHN1 Using Nanopore and Illumina Sequencing and Hybrid Assembly.

ABSTRACTWe report an improved, nearly closed, high-quality draft genome reconstruction of the Candida albicans CHN1 strain (ATCC MYA-4779), a human isolate, using Illumina and Nanopore sequencing. Covering six complete and two partial nuclear chromosomes along with a partial mitochondrial genome, this assembly is 14,787,852 bases in size, with 5,935 genes.

Genetic Characterization of a New HIV-1 Sub-Subtype A in Cabo Verde, Denominated A8.

Previous molecular characterization of Human immunodeficiency virus (HIV-1) samples from Cabo Verde pointed out a vast HIV-1 pol diversity, with several subtypes and recombinant forms, being 5.2% classified as AU-pol. Thus, the aim of the present study was to improve the characterization of these AU sequences. The genomic DNA of seven HIV-1 AU pol-infected individuals were submitted to four overlapping nested-PCR fragments aiming to compose the full-length HIV-1 genome. The final classification was based on phylogenetic trees that were generated using the maximum likelihood and bootscan analysis. The genetic distances were calculated using Mega 7.0 software. Complete genome amplification was possible for two samples, and partial genomes were obtained for the other five. These two samples grouped together with a high support value, in a separate branch from the other sub-subtypes A and CRF26_A5U. No recombination was verified at bootscan, leading to the classification of a new sub-subtype A. The intragroup genetic distance from the new sub-subtype A at a complete genome was 5.2%, and the intergroup genetic varied from 8.1% to 19.0% in the analyzed fragments. Our study describes a new HIV-1 sub-subtype A and highlights the importance of continued molecular surveillance studies, mainly in countries with high HIV molecular diversity.

Dynamics of replication origin over-activation

Safeguards against excess DNA replication are often dysregulated in cancer, and driving cancer cells towards over-replication is a promising therapeutic strategy. We determined DNA synthesis patterns in cancer cells undergoing partial genome re-replication due to perturbed regulatory interactions (re-replicating cells). These cells exhibited slow replication, increased frequency of replication initiation events, and a skewed initiation pattern that preferentially reactivated early-replicating origins. Unlike in cells exposed to replication stress, which activated a novel group of hitherto unutilized (dormant) replication origins, the preferred re-replicating origins arose from the same pool of potential origins as those activated during normal growth. Mechanistically, the skewed initiation pattern reflected a disproportionate distribution of pre-replication complexes on distinct regions of licensed chromatin prior to replication. This distinct pattern suggests that circumventing the strong inhibitory interactions that normally prevent excess DNA synthesis can occur via at least two pathways, each activating a distinct set of replication origins.

Full-Genome Sequences of Alphacoronaviruses and Astroviruses from Myotis and Pipistrelle Bats in Denmark.

Bat species worldwide are receiving increased attention for the discovery of emerging viruses, cross-species transmission, and zoonoses, as well as for characterizing virus infections specific to bats. In a previous study, we investigated the presence of coronaviruses in faecal samples from bats at different locations in Denmark, and made phylogenies based on short, partial ORF1b sequences. In this study, selected samples containing bat coronaviruses from three different bat species were analysed, using a non-targeted approach of next-generation sequencing. From the resulting metagenomics data, we assembled full-genome sequences of seven distinct alphacoronaviruses, three astroviruses, and a polyomavirus, as well as partial genome sequences of rotavirus H and caliciviruses, from the different bat species. Comparisons to published sequences indicate that the bat alphacoronaviruses belong to three different subgenera—i.e., Pedacovirus, Nyctacovirus, and Myotacovirus—that the astroviruses may be new species in the genus Mamastrovirus, and that the polyomavirus could also be a new species, but unassigned to a genus. Furthermore, several viruses of invertebrates—including two Rhopalosiphum padi (aphid) viruses and a Kadipiro virus—present in the faecal material were assembled. Interestingly, this is the first detection in Europe of a Kadipiro virus.

Lumpy skin disease outbreak in cattle population of Chattogram, Bangladesh.

BackgroundLumpy skin disease (LSD) is an important viral disease causing significant economic losses in commercial livestock production. In mid‐2019, an outbreak of LSD has been reported in cattle population from different parts of Bangladesh including Chattogram division. A cross‐sectional surveillance study was undertaken from August 2019 to December 2019 to investigate the prevalence and associated risk factors of LSD in cattle in Chattogram district.MethodsA total of 3,327 cattle from 19 commercial farms were examined for the LSD specific skin lesions and associated risk factors. A total of 120 skin biopsies were collected from the suspected animal for the confirmation of the disease using molecular detection and histopathological examination. Partial genome sequencing and phylogenetic analyses were performed on selected viral isolates.ResultsThe overall clinical prevalence of LSD in the study population was 10% (95% confidence interval [CI]: 9.4%–11%) where the highest farm level outbreak frequency was 63.33% (95% CI: 45.51%–78.13%) and the lowest 4.22% (95% CI: 3.39%–5.25%). Crossbred and female cattle showed a significantly higher prevalence of the disease compared to their counterparts. Introduction of new animals in farms was found to be one of the most significant risk factors in the transmission of the disease. All suspected skin biopsies were positive for LSD virus (LSDV) infection with granulomatous and pyogranulomatous dermatitis was revealed on histopathology. Phylogenetic analysis based on the inverted terminal repeat region of the LSDV gene suggested that the locally circulating strain was closely related to the strains isolated from the Middle East and North African countries.ConclusionsThe data generated in this study would be beneficial to the field veterinarians and animal health decision makers in the country as well as it will aid in taking appropriate measures to prevent further relapse or outbreak of this disease in future.

Comparative genomic analysis demonstrates that true reinfection following SARS-CoV-2 infection is possible

BackgroundIn recent months, multiple cases of confirmed SARS-CoV-2 reinfection have been reported. However, accurate epidemiological and virological data, including genomic analysis where possible, are required to differentiate cases of prolonged viral RNA shedding (i.e. intermittent detection) from true reinfection. The objective of this review was to systematically identify and summarise all cases of SARS-CoV-2 reinfection confirmed by comparative genomic analysis. MethodsA protocol based on Cochrane rapid review methodology was employed. Databases and pre-print servers were searched until 9/11/2020. ResultsTen studies, representing 17 patients, were identified (mean age=40; 71% male). The time interval between primary infection and reinfection ranged from 13 to 142 days (median: 60).Comparative whole genome sequencing confirmed reinfection in 14 patients (the primary and secondary infections were caused by different viruses). A further three cases had strong, but not confirmed evidence of reinfection, as only partial genomes were retrieved on primary infection.Across 12 studies that reported the number of single nucleotide polymorphisms (SNPs) comparing the first and second genomes, between 8 and 24 SNPs were discovered. With an average SARS-CoV-2 mutation acquisition rate of 1–2 per month, in all cases it is likely that the secondary infection was caused by a different SARS-CoV-2 virus, rather than prolonged shedding of viral RNA from the primary infection.In five reinfection cases, the primary and secondary infections were caused by different SARS-CoV-2 lineages/clades, strongly indicating that infections were caused by different viruses. ConclusionComparative genomic analyses from 14 patients confirm that SARS-CoV-2 reinfection can occur.

Cyanophage Diversity and Community Structure in Dead Zone Sediments.

Up to 20% of prokaryotic organisms in the oceans are estimated to die every day due to viral infection and lysis. Viruses can therefore alter microbial diversity, community structure, and biogeochemical processes driven by these organisms. Cyanophages are viruses that infect and lyse cyanobacterial cells, adding bioavailable carbon and nutrients into the environment. Cyanobacteria are photosynthesizing bacteria, with some species capable of N2 fixation, which are known to form large blooms as well as resistant resting cells known as akinetes. Here, we investigated cyanophage diversity and community structure plus cyanobacteria in dead zone sediments. We sampled surface sediments and sequenced DNA and RNA, along an oxygen gradient-representing oxic, hypoxic, and anoxic conditions-in one of the world's largest dead zones located in the Baltic Sea. Cyanophages were detected at all stations and, based on partial genome contigs, had a higher alpha diversity and different beta diversity in the hypoxic-anoxic sediments, suggesting that cyanobacteria in dead zone sediments and/or environmental conditions select for specific cyanophages. Some of these cyanophages can infect cyanobacteria with potential consequences for gene expression related to their photosystem and phosphate regulation. Top cyanobacterial genera detected in the anoxic sediment included Dolichospermum/Anabaena, Synechococcus, and Cyanobium RNA transcripts classified to cyanobacteria were associated with numerous pathways, including anaerobic carbon metabolism and N2 fixation. Cyanobacterial blooms are known to fuel oxygen-depleted ecosystems with phosphorus (so-called internal loading), and our cyanophage data indicate the potential for viral lysis of cyanobacteria which might explain the high nutrient turnover in these environments.IMPORTANCE Cyanophages are viruses that target cyanobacteria and directly control their abundance via viral lysis. Cyanobacteria are known to cause large blooms in water bodies, substantially contributing to oxygen depletion in bottom waters resulting in areas called dead zones. Our knowledge of cyanophages in dead zones is very scarce, and so far, no studies have assembled partial cyanophage genomes and investigated their associated cyanobacteria in these dark and anoxic sediments. Here, we present the first study using DNA and RNA sequencing to investigate in situ diversity of cyanophages and cyanobacteria in dead zones. Our study shows that dead zone sediments contain different cyanophages compared to oxic sediments and suggest that these viruses are able to affect cyanobacterial photosystem and phosphate regulation. Furthermore, cyanophage-controlled lysis of cyanobacteria might also increase the turnover of carbon, phosphorus, and nitrogen in these oxygen-free environments at the bottom of the sea.