Genomic Components Research Articles

Natural diversity of heat-induced transcription of retrotransposons in Arabidopsis thaliana.

Transposable elements (TEs) are major components of plant genomes, profoundly impacting the fitness of their hosts. However, technical bottlenecks have long hindered our mechanistic understanding of TEs. Using RNA-Seq and long-read sequencing with Oxford Nanopore Technologies' (ONT) direct cDNA sequencing, we analyzed the heat-induced transcription of TEs in three natural accessions of Arabidopsis thaliana (Cvi-0, Col-0, and Ler-1). In addition to the well-studied ONSEN retrotransposon family, we confirmed Copia-35 as a second heat-responsive retrotransposon family with particularly high activity in the relict accession Cvi-0. Our analysis revealed distinct expression patterns of individual TE copies and suggest different mechanisms regulating the GAG protein production in the ONSEN versus Copia-35 families. In addition, analogously to ONSEN, Copia-35 activation led to the upregulation of flanking genes such as AMUP9 and potentially to the quantitative modulation of flowering time. ONT data allowed us to test the extent to which read-through formation are important in the regulation of adjacent genes. Unexpectedly, our results indicate that for both families, the upregulation of flanking genes is not predominantly directly initiated by transcription from their 3' LTRs. These findings highlight the intraspecific expressional diversity linked to retrotransposon activation under stress.

Comparative satellite DNA mapping in species of the genus Prochilodus (Teleostei, Characiformes) and its evolutionary implications.

Satellite DNA (satDNA) sequences are dynamic components of the eukaryotic genome, that can play significant roles in species diversification. The Prochilodontidae family, which includes 21 Neotropical fish species, is characterized by a conserved karyotype of 2n = 54 biarmed chromosomes, with variation in some species and populations regarding the presence or absence of B chromosomes. This study aimed to investigate whether the chromosomal distribution of specific satDNA sequences is conserved among three Prochilodus species (P. lineatus, P. costatus, and P. argenteus) regarding organization and number of loci, and to compare their genomes using comparative genomic hybridization (CGH). Our results demonstrated that most satDNA sequences share a similar distribution pattern across the three species, and CGH analysis corroborated that their karyotypes are very similar in terms of repetitive DNA distribution. We also identified a potential CENP-B box sequence within PliSat01, a satDNA located in the pericentromeric region of all analyzed species. In contrast, PliSat04 and PliSat14 displayed differential locations and variations in the number of loci per genome, underscoring the dynamic nature of repetitive sequences even in species with otherwise highly conserved genomes. These findings represent the first evidence of karyotype diversification in Prochilodus, highlighting the evolutionary dynamism of satDNA sequences.

The burst of satellite DNA in Leptidea wood white butterflies and their putative role in karyotype evolution.

Satellite DNAs (satDNAs) are abundant components of eukaryotic genomes, playing pivotal roles in chromosomal organization, genome stability and evolution. Here, we combined cytogenetic and genomic methods to characterize the satDNAs in the genomes of Leptidea butterflies. Leptidea is characterized by the presence of a high heterochromatin content, large genomes and extensive chromosomal reshuffling as well as the occurrence of cryptic species. We show that, in contrast to other Lepidoptera, satDNAs constitute a considerable proportion of Leptidea genomes, ranging between 4.11%-11.05%. This amplification of satDNAs, together with the hyperactivity of transposable elements, contributes to the substantial genome expansion in Leptidea. Using chromosomal mapping, we show that, particularly LepSat01-100 and LepSat03-167 satDNAs, are preferentially localized in heterochromatin exhibiting variable distribution that could influence in the highly diverse karyotypes within the genus. The satDNAs also exhibit W-chromosome accumulation, suggesting their involvement in sex chromosome evolution. Our results provide insights into the dynamics of satDNAs in Lepidoptera genomes and highlight their role in genome expansion and chromosomal organization, which could influence the speciation process. The high proportion of repetitive DNAs in the genomes of Leptidea underscores the complex evolutionary dynamics revealing the interplay between repetitive DNAs and genomic architecture in the genus.

Whole-genome sequencing of Klebsiella pneumoniae MDR circulating in a pediatric hospital setting: a comprehensive genome analysis of isolates from Guayaquil, Ecuador

BackgroundKlebsiella pneumoniae is the major cause of nosocomial infections worldwide and is related to a worsening increase in Multidrug-Resistant Bacteria (MDR) and virulence genes that seriously affect immunosuppressed patients, long-stay intensive care patients, elderly individuals, and children. Whole-Genome Sequencing (WGS) has resulted in a useful strategy for characterizing the genomic components of clinically important bacteria, such as K. pneumoniae, enabling them to monitor genetic changes and understand transmission, highlighting the risk of dissemination of resistance and virulence associated genes in hospitals. In this study, we report on WGS 14 clinical isolates of K. pneumoniae from a pediatric hospital biobank of Guayaquil, Ecuador.ResultsThe main findings revealed pronounced genetic heterogeneity among the isolates. Multilocus sequencing type ST45 was the predominant lineage among non-KPC isolates, whereas ST629 was found more frequently among KPC isolates. Phylogenetic analysis suggested local transmission dynamics. Comparative genomic analysis revealed a core set of 3511 conserved genes and an open pangenome in neonatal isolates. The diversity of MLSTs and capsular types, and the high genetic diversity among these isolates indicate high intraspecific variability. In terms of virulence factors, we identified genes associated with adherence, biofilm formation, immune evasion, secretion systems, multidrug efflux pump transporters, and a notably high number of genes related to iron uptake. A large number of these genes were detected in the ST45 isolate, whereas iron uptake yersiniabactin genes were found exclusively in the non-KPC isolates. We observed high resistance to commonly used antibiotics and determined that these isolates exhibited multidrug resistance including β-lactams, aminoglycosides, fluoroquinolones, quinolones, trimetropins, fosfomycin and macrolides; additionally, resistance-associated point mutations and cross-resistance genes were identified in all the isolates. We also report the first K. pneumoniae KPC-3 gene producers in Ecuador.ConclusionsOur WGS results for clinical isolates highlight the importance of MDR in neonatal K. pneumoniae infections and their genetic diversity. WGS will be an imperative strategy for the surveillance of K. pneumoniae in Ecuador, and will contribute to identifying effective treatment strategies for K. pneumoniae infections in critical units in patients at stratified risk.

Investigation of chimeric transcripts derived from LINE-1 and Alu retrotransposons in cerebellar tissues of individuals with autism spectrum disorder (ASD)

LINE-1 and Alu retrotransposons are components of the human genome and have been implicated in many human diseases. These elements can influence human transcriptome plasticity in various mechanisms. Chimeric transcripts derived from LINE-1 and Alu can also impact the human transcriptome, such as exonization and post-transcriptional modification. However, its specific role in ASD neuropathology remains unclear, particularly in the cerebellum tissues. We performed RNA-sequencing of post-mortem cerebellum tissues from ASD and unaffected individuals for transposable elements profiling and chimeric transcript identification. The majority of free transcripts of transposable elements were not changed in the cerebellum tissues of ASD compared with unaffected individuals. Nevertheless, we observed that chimeric transcripts derived from LINE-1 and Alu were embedded in the transcripts of differentially expressed genes in the cerebellum of ASD, and these genes were related to developments and abnormalities of the cerebellum. In addition, the expression levels of these genes were correlated with the significantly decreased thickness of the molecular layer in the cerebellum of ASD. We also found that global methylation and expression of LINE-1 and Alu elements were not changed in ASD, but observed in the ASD sub-phenotypes. Our findings showed associations between transposable elements and cerebellar abnormalities in ASD, particularly in distinct phenotypic subgroups. Further investigations using appropriate models are warranted to elucidate the structural and functional implications of LINE-1 and Alu elements in ASD neuropathology.

Deficiency of interleukin-1 receptor antagonist in mice differentially affects bone properties under different genomic backgrounds

When IL-1 receptor antagonist (IL-1rn) is knocked out, mice have shown strain background dependent and major QTL regulated susceptibility to spontaneously inflammatory arthritis disease (SAD). The impact on bone properties resulting from the interactions of IL-1rn, genomic background strains, and the QTL locus, is unknown. Bone properties in the four specifically bred mouse strains with mutation of IL-1rn and variations in genomic components were investigated with high-resolution MicroCT and genomic analytical tools. Two congenic mouse strains were also measured to evaluate the influence on bone properties by a QTL in the region in chromosome 1. Our results reveal that several bone phenotypes, including bone mineral density (BMD), bone volume, tibial length, and cortical thickness of the tibia are different between wild type and IL-1rn knockout mice in both Balb/c and DBA/1 backgrounds, but IL-1rn knockout affects BMD differently between the two mouse strains. The absence of IL-1rn decreases BMD in Balb/c mice but increases BMD in DBA/1−/− mice compared to their respective wild type counterparts. A QTL transferred from the Balb/c genetic background which affects arthritis in congenic strains appears to also regulate BMD. While several genes, including Ctsg and Prg2, may affect BMD, Ifi202b is the most favored candidate gene for regulating BMD as well as SAD. In conclusion, the previously mentioned bone phenotypes are each influenced in different ways by the loss of IL-1ra when considered in mice from varying genomic backgrounds.

Decoding the genomic landscape of chromatin-associated biomolecular condensates

Biomolecular condensates play a significant role in chromatin activities, primarily by concentrating and compartmentalizing proteins and/or nucleic acids. However, their genomic landscapes and compositions remain largely unexplored due to a lack of dedicated computational tools for systematic identification in vivo. To address this, we develop CondSigDetector, a computational framework designed to detect condensate-like chromatin-associated protein co-occupancy signatures (CondSigs), to predict genomic loci and component proteins of distinct chromatin-associated biomolecular condensates. Applying this framework to mouse embryonic stem cells (mESC) and human K562 cells enable us to depict the high-resolution genomic landscape of chromatin-associated biomolecular condensates, and uncover both known and potentially unknown biomolecular condensates. Multi-omics analysis and experimental validation further verify the condensation properties of CondSigs. Additionally, our investigation sheds light on the impact of chromatin-associated biomolecular condensates on chromatin activities. Collectively, CondSigDetector provides an approach to decode the genomic landscape of chromatin-associated condensates, facilitating a deeper understanding of their biological functions and underlying mechanisms in cells.

Biological and Molecular Characterization of the Cucumber Mosaic Virus Infecting Purple Coneflowers in China

Purple coneflower (Echinacea purpurea L.), which is a perennial herbaceous plant belonging to the Asteraceae family, is extensively cultivated because of its medicinal applications. However, in Hohhot, Inner Mongolia, China, purple coneflowers in the field exhibited symptoms such as mottle, mosaic, and crinkle. This study aimed to explore the biological and molecular characteristics of the cucumber mosaic virus (CMV) infecting the purple coneflowers in China. We observed isometric particles approximately 30 nm in diameter in the symptomatic leaf specimens. Infection with the CMV was confirmed via high-throughput sequencing and RT-PCR validation. Mechanical inoculation assays demonstrated that the CMV-SGJ isolate could infect both Nicotiana benthamiana and Nicotiana tabacum. Three viral genomic components were identified: RNA1 with 3321 nucleotides, RNA2 with 3048 nucleotides, and RNA3 with 2209 nucleotides. Phylogenetic analysis revealed that the CMV-SGJ isolate clustered into phylogenetic subgroup IA, exhibiting a nucleotide identity of 92.2–95% with subgroup IA CMV isolates in GenBank. This report is the first documentation of the complete genome of the CMV infecting purple flowers in China.

HPV16 Genomes: In Silico Analysis of E6 and E7 Oncoproteins in 20 South American Variants.

Human papillomavirus (HPV) is the main risk factor for the development of squamous cell cervical cancer, and E6 oncoprotein and E7 oncoprotein are important components of the viral genome and its oncogenic potential. It is known that different viral variants of HPV16 have different pathology and impact on the development of neoplasia, although few studies have been performed on South American variants. Therefore, the present study aimed to analyze in silico the genomic diversity of HPV16 in 20 complete genome variants of South America in the National Center for Biotechnology Information (NCBI) database. We performed a descriptive study to characterize the polymorphic regions of the E6 and E7 genes in HPV16 variants, using software for genomic data and single nucleotide polymorphism (SNP) analysis and others for phylogenetic analysis. The variants analyzed included six SNPs linked to cancer (A131G, G145T, C335T, T350G, C712A, and T732C) and significant variation (798 nucleotide substitutions). Despite this, the variants showed low genetic diversity. Eighteen variants of unclear significance (VUS) were identified, 10 of which were in the coding E6 regions and 8 in the coding E7 regions. The prevalence of lineage D variants is of concern due to their pathology in cervical cancer and requires more research and epidemiological vigilance regarding their prevalence in the population. The data obtained in this study may contribute to future research on South American variants of HPV16, their pathogenicity, and the development of treatments.

Molecular Analysis of Persistent and Recurrent Barrett's Esophagus in the Setting of Endoscopic Therapy.

Early neoplastic progression of Barrett's esophagus (BE) is often treated with endoscopic therapy. Although effective, some patients are refractory to therapy or recur after apparent eradication of the BE. The goal of this study was to determine whether genomic alterations within the treated BE may be associated with persistent or recurrent disease. We performed DNA sequencing on pre-treatment esophageal samples from 45 patients who were successfully treated by endoscopic therapy and did not recur as well as pre-treatment and post-treatment samples from 40 patients who had persistent neoplasia and 21 patients who had recurrent neoplasia. The genomic alterations were compared between groups. The genomic landscape was similar between all groups. Patients with persistent disease were more likely to have pre-treatment alterations involving the receptor tyrosine kinase pathway ( P = 0.01), amplifications of oncogenes ( P = 0.01), and deletions of tumor suppressor genes ( P = 0.02). These associations were no longer significant after adjusting for patient age and BE length. More than half of patients with persistent (52.5%) or recurrent (57.2%) disease showed pre-treatment and post-treatment samples that shared at least 50% of their driver mutations. Pre-treatment samples were genomically similar between those who responded to endoscopic therapy and those who had persistent or recurrent disease, suggesting there is not a strong genomic component to treatment response. Although it was expected to find shared driver mutations in pre-treatment and post-treatment samples in patients with persistent disease, the finding that an equal number of patients with recurrent disease also showed this relation suggests that many recurrences represent undetected minimal residual disease.

Genetic differentiation across a steep and narrow environmental gradient: Quantitative genetic and genomic insights into Lake Superior populations of Quercus rubra.

Adaptive differentiation of traits and underlying loci can occur at a small geographical scale if natural selection is stronger than countervailing gene flow and drift. We investigated this hypothesis using coupled quantitative genetic and genomic approaches for a wind-pollinated tree species, Quercus rubra, along the steep, narrow gradient of the Lake Superior coast that encompasses four USDA Hardiness Zones within 100 km. For the quantitative genetic component of this study, we examined phenotypic differentiation among eight populations in a common garden, measuring seed mass, germination, height, stem diameter, leaf number, specific leaf area and survival. For the genomic component, we quantified genetic differentiation for 26 populations from the same region using RAD-seq. Because hybridisation with Quercus ellipsoidalis occurs in other parts of the species' range, we included two populations of this congener for comparison. In the common garden study, we found a strong signal of population differentiation that was significantly associated with at least one climate factor for nine of 10 measured traits. In contrast, we found no evidence of genomic differentiation among populations based on FST or any other measures. However, both distance-based and genotype-environment association analyses identified loci showing the signature of selection, with one locus in common across five analyses. This locus was associated with the minimum temperature of the coldest month, a factor that defines the climate zones and was also significant in the common garden analyses. In addition, we documented introgression from Q. ellipsoidalis into Q. rubra, with rates of introgression correlated with the climate gradient. In sum, this study reveals signatures of selection at the quantitative trait and genomic level consistent with climate adaptation, a pattern that is more often documented at a much broader geographical scale, especially in long-lived wind-pollinated species.

Partitioning the Genomic Components of Behavioral Disinhibition and Substance Use (Disorder) Using Genomic Structural Equation Modeling.

Externalizing behaviors encompass manifestations of risk-taking, self-regulation, aggression, sensation-/reward-seeking, and impulsivity. Externalizing research often includes substance use (SUB), substance use disorder (SUD), and other (non-SUB/SUD) "behavioral disinhibition" (BD) traits. Genome-wide and twin research have pointed to overlapping genetic architecture within and across SUB, SUD, and BD. We created single-factor measurement models-each describing SUB, SUD, or BD traits-based on mutually exclusive sets of European ancestry genome-wide association study (GWAS) statistics exploring externalizing variables. We then assessed the partitioning of genetic covariance among the three facets using correlated factors models and Cholesky decomposition. Even when the residuals for indicators relating to the same substance were correlated across the SUB and SUD factors, the two factors yielded a large correlation (rg=0.803). BD correlated strongly with the SUD (rg=0.774) and SUB (rg=0.778)factors. In our initial decompositions, 33% of total BD variance remained after partialing out SUD and SUB. The majority of covariance between BD and SUB and between BD and SUD was shared across all factors, and, within these models, only a small fraction of the total variation in BD operated via an independent pathway with SUD or SUB outside of the other factor. When only nicotine/tobacco, cannabis, and alcohol were included for the SUB/SUD factors, their correlation increased to rg=0.861; in corresponding decompositions, BD-specific variance decreased to 27%. Further research can better elucidate the properties of BD-specific variation by exploring its genetic/molecular correlates.

Expression of Transposable Elements throughout the Fasciola hepatica Trematode Life Cycle.

Transposable elements (TEs) are major components of eukaryotic genomes. The extensive body of evidence suggests that although they were once considered "genomic parasites", transposons and their transcripts perform specific functions, such as regulation of early embryo development. Understanding the role of TEs in such parasites as trematodes is becoming critically important. Fasciola hepatica, a parasite affecting humans and livestock, undergoes a complex life cycle in diverse environments and hosts, and knowledge about its life cycle regulation is scarce so far. We summarized the data regarding the repetitive elements in F. hepatica and conducted bulk RNA-seq analysis across its life cycle stages. TE expression profiles were analyzed, focusing on differential expression and potential homology with previously described long non-coding RNAs (lncRNAs). Differential expression analysis revealed stage-specific TE transcription patterns, notably peaking during egg and metacercariae stages. Some TEs showed homology with known lncRNAs and contained putative transcription factor binding sites. Interestingly, TE transcription levels were highest in eggs and metacercariae compared to adults, suggesting regulatory roles in trematode life cycle transitions. These findings suggest that TEs may play roles in regulating trematode life cycle transitions. Moreover, TE homology with lncRNAs underscores their significance in gene regulation.

Dickeya fangzhongdai was prevalent and caused taro soft rot when coexisting with the Pectobacterium complex, with a preference for Araceae plants.

Bacterial soft rot caused by coinfection with Dickeya spp. and Pectobacterium spp. in hosts can cause successive changes in fields, and it is difficult to prevent the spread of and control the infection. Pectobacterium spp. are prevalent in the growing areas of tuberous crops, including taro and potato. Recently, Dickeya fangzhongdai has emerged as a virulent pathogen in taro. To determine the prevalence status of the causal agents and evaluate the potential spreading risks of D. fangzhongdai, screening and taxonomic classification were performed on phytopathogenic bacteria collected from different taro-growing areas in Guangdong Province, China, and biological and genomic characteristics were further compared among typical strains from all defined species. The causative agents were verified to be phytobacterial strains of D. fangzhongdai, Pectobacterium aroidearum and Pectobacterium colocasium. P. aroidearum and P. colocasium were found to form a complex preferring Araceae plants and show intensive genomic differentiation, indicating their ancestor had adapted to taro a long time prior. Compared with Pectobacterium spp., D. fangzhongdai was more virulent to taro corms under conditions of exogenous infection and more adaptable at elevated temperatures. D. fangzhongdai strains isolated from taro possessed genomic components of additional T4SSs, which were accompanied by additional copies of the hcp-vgrG genes of the T6SS, and these contributed to the expansion of their genomes. More gene clusters encoding secondary metabolites were found within the D. fangzhongdai strains than within the Pectobacterium complex; interestingly, distinct gene clusters encoding zeamine and arylpolyene were both most similar to those in D. solani that caused potato soft rot. These comparisons provided genomic evidences for that the newly emerging pathogen was potentially equipped to compete with other pathogens. Diagnostic qPCR verified that D. fangzhongdai was prevalent in most of the taro-growing areas and coexisted with the Pectobacterium complex, while the plants enriching D. fangzhongdai were frequently symptomatic at developing corms and adjacent pseudostems and caused severe symptoms. Thus, the emerging need for intensive monitoring on D. fangzhongdai to prevent it from spreading to other taro-growing areas and to other tuberous crops like potato; the adjustment of control strategies based on different pathopoiesis characteristics is recommended.

Identification of mungbean yellow mosaic India virus and susceptibility-related metabolites in the apoplast of mung bean leaves.

The investigation of MYMIV-infected mung bean leaf apoplast revealed viral genome presence, increased EVs secretion, and altered stress-related metabolite composition, providing comprehensive insights into plant-virus interactions. The apoplast, an extracellular space around plant cells, plays a vital role in plant-microbe interactions, influencing signaling, defense, and nutrient transport. While the involvement of apoplast and extracellular vesicles (EVs) in RNA virus infection is documented, the role of the apoplast in plant DNA viruses remains unclear. This study explores the apoplast's role in mungbean yellow mosaic India virus (MYMIV) infection. Our findings demonstrate the presence of MYMIV genomic components in apoplastic fluid, suggesting potential begomovirus cell-to-cell movement via the apoplast. Moreover, MYMIV infection induces increased EVs secretion into the apoplast. NMR-based metabolomics reveals altered metabolic profiles in both apoplast and symplast in response to MYMIV infection, highlighting key metabolites associated with stress and defense mechanisms. The data show an elevation of α- and β-glucose in both apoplast and symplast, suggesting a shift in glucose utilization. Interestingly, this increase in glucose does not contribute to the synthesis of phenolic compounds, potentially influencing the susceptibility of mung bean to MYMIV. Fructose levels increase in the symplast, while apoplastic sucrose levels rise significantly. Symplastic aspartate levels increase, while proline exhibits elevated concentration in the apoplast and reduced concentration in the cytosol, suggesting a role in triggering a hypersensitive response. These findings underscore the critical role of the apoplast in begomovirus infection, providing insights for targeted viral disease management strategies.

Virus versus host: influenza A virus circumvents the immune responses.

Influenza A virus (IAV) is a highly contagious pathogen causing dreadful losses to humans and animals around the globe. As is known, immune escape is a strategy that benefits the proliferation of IAVs by antagonizing, blocking, and suppressing immune surveillance. The HA protein binds to the sialic acid (SA) receptor to enter the cytoplasm and initiate viral infection. The conserved components of the viral genome produced during replication, known as the pathogen-associated molecular patterns (PAMPs), are thought to be critical factors for the activation of effective innate immunity by triggering dependent signaling pathways after recognition by pattern recognition receptors (PRRs), followed by a cascade of adaptive immunity. Viral infection-induced immune responses establish an antiviral state in the host to effectively inhibit virus replication and enhance viral clearance. However, IAV has evolved multiple mechanisms that allow it to synthesize and transport viral components by "playing games" with the host. At its heart, this review will describe how host and viral factors interact to facilitate the viral evasion of host immune responses.

Genomic and Transcriptome Analysis Reveals the Biosynthesis Network of Cordycepin in Cordyceps militaris.

Cordycepin is the primary active compound of Cordyceps militaris. However, the definitive genetic mechanism governing cordycepin synthesis in fruiting body growth and development remains elusive, necessitating further investigation. This study consists of 64 C. militaris strains collected from northeast China. The high-yielding cordycepin strain CMS19 was selected for the analysis of cordycepin production and the genetic basis of cordycepin anabolism. First, the whole-genome sequencing of CMS19 yielded a final size of 30.96 Mb with 8 contigs and 9781 protein-coding genes. The genome component revealed the presence of four additional secondary metabolite gene clusters compared with other published genomes, suggesting the potential for the production of new natural products. The analyses of evolutionary and genetic differentiation revealed a close relationship between C. militaris and Beauveria bassiana. The population of strains distributed in northeast China exhibited the significant genetic variation. Finally, functional genes associated with cordycepin synthesis were identified using a combination of genomic and transcriptomic analyses. A large number of functional genes associated with energy and purine metabolism were significantly enriched, facilitating the reconstruction of a hypothetical cordycepin metabolic pathway. Therefore, our speculation of the cordycepin metabolism pathway involved 24 genes initiating from the glycolysis and pentose phosphate pathways, progressing through purine metabolism, and culminating in the core region of cordycepin synthesis. These findings could offer fundamental support for scientific utilizations of C. militaris germplasm resources and standardized cultivation for cordycepin production.

Comparative analysis of transposable elements dynamics in fish with different sex chromosome systems.

Transposable elements (TEs) are widespread genomic components with substantial roles in genome evolution and sex chromosome differentiation. In this study, we compared the TE composition of three closely related fish with different sex chromosome systems: Megaleporinus elongatus (Z1Z1Z2Z2/Z1W1Z2W2), Megaleporinus macrocephalus (ZZ/ZW) (both with highly differentiated W sex chromosomes), and Leporinus friderici (without heteromorphic sex chromosomes). We created custom TE libraries for each species using clustering methods and manual annotation and prediction, and we predicted TE temporal dynamics through divergence-based analysis. The TE abundance ranged from 16% to 21% in the three mobilomes, with L. friderici having the lowest overall. Despite the recent amplification of TEs in all three species, we observed differing expansion activities, particularly between the two genera. Both Megaleporinus recently experienced high retrotransposon activity, with a reduction in DNA TEs, which could have implications in sex chromosome composition. In contrast, L. friderici showed the opposite pattern. Therefore, despite having similar TE compositions, Megaleporinus and Leporinus exhibit distinct TE histories that likely evolved after their separation, highlighting a rapid TE expansion over short evolutionary periods.

A pan-TE map highlights transposable elements underlying domestication and agronomic traits in Asian rice.

Transposable elements (TEs) are ubiquitous genomic components and hard to study due to being highly repetitive. Here we assembled 232 chromosome-level genomes based on long-read sequencing data. Coupling the 232 genomes with 15 existing assemblies, we developed a pan-TE map comprising both cultivated and wild Asian rice. We detected 177084 high-quality TE variations and inferred their derived state using outgroups. We found TEs were one source of phenotypic variation during rice domestication and differentiation. We identified 1246 genes whose expression variation was associated with TEs but not single-nucleotide polymorphisms (SNPs), such as OsRbohB, and validated OsRbohB's relative expression activity using a dual-Luciferase (LUC) reporter assays system. Our pan-TE map allowed us to detect multiple novel loci associated with agronomic traits. Collectively, our findings highlight the contributions of TEs to domestication, differentiation and agronomic traits in rice, and there is massive potential for gene cloning and molecular breeding by the high-quality Asian pan-TE map we generated.

First report of Tomato leaf curl New Delhi virus (a bipartite begomovirus) from round gourd plant in Swat region of Pakistan: its phylogenetic and biogeographic analysis

Background: The family Geminiviridae contains plant viruses commonly referred to as geminiviruses, which cause diseases in numerous important plants. Geminiviridae is one of the most important family of plant-infecting viruses that has been divided into fourteen recognized genera. Amongst these, the genus Begomovirus is the largest and economically most important one, viruses of the genus are further categorized into bipartite (two genomic components called DNA-A and DNA-B) and monopartite (single genomic component or DNA-A) begomoviruses.Method: The genomic DNA was extracted from symptomatic plant samples and both the DNA-(B and A) components of a bipartite begomovirus were amplified via rolling circular amplification (RCA) and PCR. The amplified DNA-A and DNA-B were cloned and sequenced by Primer walking, Sanger sequencing, and Illumina sequencing methods. The phylogenetic and biogeographic analyses of both components were performed by various bioinformatics tools.Results: DNA-A (accession number MW722701) and DNA-B (accession number MW722782) of begomoviruses that were sequenced shared >95% sequence similarity with the bipartite begomovirus known as Tomato Leaf Curl New Delhi virus (TLCuNDV). Phylogenetic and biogeographic analyses proposed several possible ancestors, and multiple dispersal and vicariance events may be involved in the evolution of this virus. Conclusions: This is the first time a bipartite begomovirus has been found to infect a plant in the study area (District Swat, Pakistan). The existence of ToLCNDV may pose a major danger to other important crops in the region.Keywords: Bipartite Begomoviruses; Phylogeny; Biogeography; BLAST; S-DIVA; BBM; DEC