Rfam 14: expanded coverage of metagenomic, viral and microRNA families

Telomere-to-telomere genome assembly reveals insights into the adaptive evolution of herbivore-defense mediated by volatile terpenoids in Oenanthe javanica

Releasing large quantities of volatiles is a defense strategy used by plants to resist herbivore attack. Oenanthe javanica, a perennial herb of the Apiaceae family, has a distinctive aroma due to volatile terpenoid accumulation. At present, the complete genome and genetic characteristics of volatile terpenoids in O. javanica remain largely unclear. Here, the telomere-to-telomere genome of O. javanica, with a size of 1012.13 Mb and a contig N50 of 49.55 Mb, was established by combining multiple sequencing technologies. Comparative genome analysis revealed that O. javanica experienced a recent species-specific whole-genome duplication event during the evolutionary process. Numerous gene family expansions were significantly enriched in the terpenoid biosynthesis process, monoterpenoid, and diterpenoid biosynthesis pathways, which resulted in abundant volatile substance accumulation in O. javanica. The volatile terpenoids of O. javanica showed repellent effects on herbivores. Terpenoid biosynthesis was activated by wounding signals under exogenous stimuli. The TPS gene family was significantly expanded in O. javanica compared to those in other species, and the members (OjTPS1, OjTPS3, OjTPS4, OjTPS5, OjTPS7, OjTPS16, OjTPS18, OjTPS30 and OjTPS58) responsible for different terpenoid biosynthesis were functionally characterized. These results reveal the genome evolution and molecular characteristics of volatile terpenoids in the process of plant-herbivore interactions. This study also provides genomic resources for genetic and molecular biology research on O. javanica and other plants.

Altered levels of angiogenin and tRNA-derived fragments associate with severe asthma

Recent discoveries highlight angiogenin (ANG) and 5' tRNA-derived fragments as key factors in stress response and cell survival. To explore their role in asthma pathogenesis, particularly in severe cases, we evaluated the levels of ANG and 5' tRNA halves (tRHs) derived from tRNA Glu (5'-tRH Glu: tRF-32-87R8WP9N1EWJM) and tRNA Gly (5'-tRH Gly: tRF-30-PNR8YP9LON4V), two abundant tRHs in the respiratory tract, in sputum and blood samples from asthmatic patients. We found ANG expression is significantly increased in circulating leukocytes from severe asthma patients but not in sputum infiltrates. On the contrary, tRHs levels showed significant alterations only in extracellular compartments. Both tRHs were downregulated in the plasma of asthmatic patients, while elevated 5'-tRH Gly levels were observed in severe sputum samples, indicating tissue-specific roles in disease pathology. Additionally, tRH expression in leukocytes was negatively associated with the disrupted corticosteroid response in asthmatic patients. Altered levels of ANG and 5'-tRH Glu and 5'-tRH Gly were further validated in an in vitro model of pollutant-aggravated, allergen-stimulated macrophages. In summary, our findings provide new insights into the role of ANG and tRHs in asthma pathogenesis, highlighting their potential as novel markers for asthma phenotyping.

Chromosome-level genome assembly of Sambus kanssuensis (Coleoptera: Buprestidae)

Sambus kanssuensis Ganglbauer, 1890 (Coleoptera: Buprestidae), distributed in Gansu and Sichuan Provinces of China, is a phytophagous pest that feeds on the toxic plant Buddleja. However, the genomic resources of this beetle remain unknown, which impedes the understanding of its ecological adaptations. Consequently, this study presents a complete, well-assembled, and annotated genome of S. kanssuensis. The assembled results indicate a genome size of 312.42 Mb, comprising 206 scaffolds, with an N50 of 34.04 Mb; 98.68% of the assembly sequences were anchored to 11 chromosomes, including one sex chromosome. The genome contains 12,723 protein-coding genes, of which 11,977 have been annotated. BUSCO analysis revealed that the completeness of the chromosome-level genome is 97.9%. This chromosome-level genome provides valuable data for further investigations into detoxification mechanisms, ecological adaptations, population genetics, and the evolution of Buprestidae.

A vetiver-specific terpene synthase VzTPS9 contributes to the high attractiveness of vetiver to rice stem borer

Vetiver (Vetiveria zizanioides) is highly attractive to the rice stem borer (Chilo suppressalis, RSB) and is widely utilized as a trap plant for RSB control in East Asia. However, the underlying mechanism driving this high level of attractiveness remains unclear. In this study, we identified volatiles emitted by vetiver using SPME/GC-MS and found that cedrol constitutes 12.15% of the total volatile profile. Both Y-tube olfactometer and electroantennography assays revealed that cedrol is highly attractive to female RSB moths at a concentration of 200 μg/μL. To investigate the mechanism responsible for the high level of cedrol in vetiver, we sequenced and assembled a chromosome-level genome of vetiver, identifying a vetiver-specific terpene synthase, VzTPS9, which is responsible for the synthesis of cedrol from farnesyl pyrophosphate (FPP). Subsequently, we constructed a transgenic rice line by integrating VzTPS9 into the rice genome. Enzyme assays and gene expression analyses demonstrated that the transgenic rice produced higher levels of cedrol, which were positively correlated with VzTPS9 expression levels, and consequently, with increased attractiveness to female RSB moths. These findings suggest that increased expression of VzTPS9 in vetiver leads to elevated cedrol synthesis, contributing to its enhanced attractiveness to RSB. This work uncovers the molecular mechanism behind vetiver's high attractiveness to RSB and provides valuable insights for developing more effective strategies for utilizing vetiver as a trap plant in RSB control.

Genomic structure of yellow lupin (Lupinus luteus): genome organization, evolution, gene family expansion, metabolites and protein synthesis

Yellow lupin (Lupinus luteus) gives valuable high-quality protein and has good sustainability due to its ability in nitrogen fixation and exudation of organic acids, which reduces the need for chemical-based phosphate fertilization in acid soils. However, the crop needs further improvements to contribute in a major way to sustainable agriculture and food security.In this study, we present the first chromosome-level genome assembly of L. luteus. The results provide insights into its genomic organization, evolution, and functional attributes. Using integrated genomic approaches, we unveil the genetic bases governing its adaptive responses to environmental stress, delineating the intricate interplay among alkaloid biosynthesis, mechanisms of pathogen resistance, and secondary metabolite transporters. Our comparative genomic analysis of closely related species highlights recent speciation events within the Lupinus genus, exposing extensive synteny preservation alongside notable structural alterations, particularly chromosome translocations. Remarkable expansions of gene families implicated in terpene metabolism, stress responses, and conglutin proteins were identified, elucidating the genetic basis of L. luteus' superior nutritional profile and defensive capabilities. Additionally, a diverse array of disease resistance-related (R) genes was uncovered, alongside the characterization of pivotal enzymes governing quinolizidine alkaloid biosynthesis, thus shedding light on the molecular mechanisms underlying "bitterness" in lupin seeds.This comprehensive genomic analysis serves as a valuable resource to improve this species in terms of resilience, yield, and seed protein levels to contribute to food and feed to face the worldwide challenge of sustainable agriculture and food security.

New insights into the cold tolerance of upland switchgrass by integrating a haplotype-resolved genome and multi-omics analysis

BACKGROUND

Switchgrass (Panicum virgatum L.) is a bioenergy and forage crop. Upland switchgrass exhibits superior cold tolerance compared to the lowland ecotype, but the underlying molecular mechanisms remain unclear.

RESULTS

Here, we present a high-quality haplotype-resolved genome of the upland ecotype "Jingji31." We then conduct multi-omics analysis to explore the mechanism underlying its cold tolerance. By comparative transcriptome analysis of the upland and lowland ecotypes, we identify many genes with ecotype-specific differential expression, particularly members of the cold-responsive (COR) gene family, under cold stress. Notably, AFB1, ATL80, HOS10, and STRS2 gene families show opposite expression changes between the two ecotypes. Based on the haplotype-resolved genome of "Jingji31," we detect more cold-induced allele-specific expression genes in the upland ecotype than in the lowland ecotype, and these genes are significantly enriched in the COR gene family. By genome-wide association study, we detect an association signal related to the overwintering rate, which overlaps with a selective sweep region containing a cytochrome P450 gene highly expressed under cold stress. Heterologous overexpression of this gene in rice alleviates leaf chlorosis and wilting under cold stress. We also verify that expression of this gene is suppressed by a structural variation in the promoter region.

CONCLUSIONS

Based on the high-quality haplotype-resolved genome and multi-omics analysis of upland switchgrass, we characterize candidate genes responsible for cold tolerance. This study advances our understanding of plant cold tolerance, which provides crop breeding for improved cold tolerance.

Immunoregulatory mechanisms and cross-kingdom bacteriostatic effects of microRNAs in crustacean

MicroRNAs (miRNAs) are crucial regulators of gene expression, which contribute to immune response regulation in various organisms, including crustaceans. To investigate the immunoregulatory roles of miRNAs in Portunus trituberculatus, a comparative miRNAomic analysis of Vibrio parahaemolyticus infection was carried out. Through comparative miRNAomic analysis, we identified 17 differentially expressed miRNAs (DE-miRNAs), of which 12 were upregulated. Subsequently, miRNA-mRNA regulatory network analysis revealed that the DE-miRNAs were enriched in immune-related signaling pathways. Within the miRNA-mRNA regulatory network, miRNA novel0045 was identified as a crucial regulator of the tumor necrosis factor (TNF) pathway via targeting the TNF receptor-associated factor 6 gene. This result was corroborated by our RNA interference assay, confirming the significance of miRNA novel0045 in resistance to V. parahaemolyticus infection. Moreover, miRNA novel0294 was noted to possess cross-kingdom regulatory potential, translocating into bacterial cells and directly inhibiting V. parahaemolyticus proliferation. We validated this finding through fluorescence labeling and confocal microscopy, confirming effective internalization and presence of miRNA within bacterial. These results expand the current understanding of miRNA-mediated immune responses in crustaceans, highlighting the roles of miRNAs in host immune defense and cross-kingdom regulatory function in bacterial infection suppression, and have potential implications in the development of RNA-based antimicrobial strategies.

An annotated near-complete sequence assembly of the Magnaporthe oryzae 70-15 reference genome

Magnaporthe oryzae is a devastating fungal pathogen that causes substantial yield losses in rice and other cereal crops worldwide. A high-quality genome assembly is critical for addressing challenges posed by this pathogen. However, the current widely used MG8 assembly of the M. oryzae strain 70-15 reference genome contains numerous gaps and unresolved repetitive regions. Here, we report a complete 44.82 Mb high-quality nuclear genome and a 35.95 kb circular mitochondrial genome for strain 70-15, generated using deep-coverage PacBio high-fidelity sequencing (HiFi) and high-resolution chromatin conformation capture (Hi-C) data. Notably, we successfully resolved one or both telomere sequences for all seven chromosomes and achieved telomere-to-telomere (T2T) assemblies for chromosomes 2, 3, 4, 6, and 7. Based on this T2T assembly, we predicted 12,100 protein-coding genes and 493 effectors. This high-quality T2T assembly represents a significant advancement in M. oryzae genomics and provides an enhanced reference for studies in genome biology, comparative genomics, and population genetics of this economically important plant pathogen.

Methyl jasmonate induces the regulation of protostane triterpene biosynthesis by microRNAs in Alisma orientale

Protostane triterpenes are medicinally important components found in members of the Alismataceae botanical family, notably Alisma orientale. Methyl jasmonate (MeJA) is known to regulate protostane triterpene biosynthesis in A. orientale, but the microRNA (miRNA) mechanism underlying MeJA response to promote triterpene biosynthesis remains unknown. In this study, we conducted miRNA sequencing analysis after MeJA induction in A. orientale to uncover the role of miRNAs in protostane triterpene biosynthesis. We identified 222 known miRNAs and 379 novel miRNAs, including 16 differentially expressed miRNAs (DEMs) between control and MeJA-treated leaf samples. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) enrichment analysis, four DEMs and eight miRNA target genes were significantly enriched in the triterpene biosynthesis pathway. Integrated analysis of the transcriptome and miRNAome revealed a negative expression pattern between miRNAs and their target genes. We then constructed a regulatory network of miRNA-target gene relationships involved in the triterpene biosynthesis pathway. We found miRNAs may be involved in the response of A. orientale to exogenous MeJA by regulating the expression of key biosynthesis enzymes, leading to increased accumulation of medically important protostane triterpenes.

Telomere-to-telomere gap-free genome assembly provides genetic insight into the triterpenoid saponins biosynthesis in Platycodon grandiflorus

Platycodon grandiflorus has been widely used in Asia as a medicinal herb and food because of its anti-inflammatory and hepatoprotective properties. P. grandiflorus has important clinical value because of the active triterpenoid saponins in its roots. However, the biosynthetic pathway of triterpenoid saponins in P. grandiflorus remains unclear, and the related genes remain unknown. Therefore, in this study, we assembled a high-quality and integrated telomere-to-telomere P. grandiflorus reference genome and combined time-specific transcriptome and metabolome profiling to identify the cytochrome P450s (CYPs) responsible for the hydroxylation processes involved in triterpenoid saponin biosynthesis. Nine chromosomes were assembled without gaps or mismatches, and nine centromeres and 18 telomere regions were identified. This genome eliminated redundant sequences from previous genome versions and incorporated structural variation information. Comparative analysis of the P. grandiflorus genome revealed that P. grandiflorus underwent a core eudicot γ-WGT event. We screened 211 CYPs and found that tandem and proximal duplications may be crucial for the expansion of CYP families. We outlined the proposed hydroxylation steps, likely catalyzed by the CYP716A/72A/749A families, in platycodin biosynthesis and identified three PgCYP716A, seven PgCYP72A, and seven PgCYP749A genes that showed a positive correlation with platycodin biosynthesis. By establishing a T2T assembly genome, transcriptome, and metabolome resource for P. grandiflorus, we provide a foundation for the complete elucidation of the platycodins biosynthetic pathway, which consequently leads to heterologous bioproduction, and serves as a fundamental genetic resource for molecular-assisted breeding and genetic improvement of P. grandiflorus.

In a nutshell: pistachio genome and kernel development

Pistachio is a sustainable nut crop with exceptional climate resilience and nutritional value. However, the molecular processes underlying pistachio nut development and nutritional traits are largely unknown, compounded by limited genomic and molecular resources. To advance pistachios as a future food source and a model system for hard-shelled fruits, we generated a chromosome-scale reference genome of the most widely grown pistachio cultivar (Pistacia vera 'Kerman') and a spatiotemporal study of nut development. We integrated tissue-level physiological data from thousands of nuts over three growing seasons with transcriptomic data encompassing 14 developmental time points of the hull, shell, and kernel to assemble gene modules associated with physiological changes. Our study defined four distinct stages of pistachio nut growth and maturation. We then focused on the kernel to identify transcriptional and metabolic changes in molecular pathways governing nutritional quality, such as the accumulation of unsaturated fatty acids, which are vital for shelf life and dietary value. These findings revealed key candidate conserved regulatory genes, such as PvAP2-WRI1 and PvNFYB-LEC1, likely involved in oil accumulation in kernels. This work yields new knowledge and resources that will inform other woody crops and facilitate further improvement of pistachio as a globally significant, sustainable, and nutritious crop.

Genome assembly of pomegranate highlights structural variations driving population differentiation and key loci underpinning cold adaption

Cold damage poses a significant challenge to the cultivation of soft-seeded pomegranate varieties, hindering the growth of the pomegranate industry. The genetic basis of cold tolerance in pomegranates has remained elusive, largely due to the lack of high-quality genome assemblies for cold-tolerant varieties and comprehensive population-scale genomic studies. In this study, we addressed these challenges by assembling a high-quality chromosome-level reference genome for 'Sanbai', a pomegranate variety renowned for its freezing resistance, achieving an impressive contig N50 of 15.93 Mb. This robust assembly, enhanced by long-read sequencing of 38 pomegranate accessions, facilitated the identification of 14 239 polymorphic structural variants, revealing their critical roles in genomic diversity and population differentiation related to cold tolerance. Of particular significance was the discovery of a ~ 5.4-Mb inversion on chromosome 1, which emerged as an important factor affecting cold tolerance in pomegranate. Moreover, through the integration of bulked segregant analysis, differential selection analysis, and genetic transformation techniques, we identified and validated the interaction between the PgNAC12 transcription factor and PgCBF1, disclosing their pivotal roles in response to cold stress. These findings mark a significant advancement in pomegranate genomics, offering novel insights into the genetic mechanisms of cold tolerance and providing valuable resources for the genetic improvement of soft-seeded pomegranate varieties.

Comprehensive expression genome-wide association study of long non-coding RNAs in four porcine tissues

BACKGROUND

Long non-coding RNAs (lncRNAs), a type of non-coding RNA molecules, are known to play critical regulatory roles in various biological processes. However, the functions of the majority of lncRNAs remain largely unknown, and little is understood about the regulation of lncRNA expression. In this study, high-throughput DNA genotyping and RNA sequencing were applied to investigate genomic regions associated with lncRNA expression, commonly referred to as lncRNA expression quantitative trait loci (eQTLs). We analyzed the liver, lung, spleen, and muscle transcriptomes of 100 three-way crossbred sows to identify lncRNA transcripts, explore genomic regions that might influence lncRNA expression, and identify potential regulators interacting with these regions.

RESULT

We identified 6380 lncRNA transcripts and 3733 lncRNA genes. Correlation tests between the expression of lncRNAs and protein-coding genes were performed. Subsequently, functional enrichment analyses were carried out on protein-coding genes highly correlated with lncRNAs. Our correlation results of these protein-coding genes uncovered terms that are related to tissue specific functions. Additionally, heatmaps of lncRNAs and protein-coding genes at different correlation levels revealed several distinct clusters. An expression genome-wide association study (eGWAS) was conducted using 535,896 genotypes and 1829, 1944, 2089, and 2074 expressed lncRNA genes for liver, spleen, lung, and muscle, respectively. This analysis identified 520,562 significant associations and 6654, 4525, 4842, and 7125 eQTLs for the respective tissues. Only a small portion of these eQTLs were classified as cis-eQTLs. Fifteen regions with the highest eQTL density were selected as eGWAS hotspots and potential mechanisms of lncRNA regulation in these hotspots were explored. However, we did not identify any interactions between the transcription factors or miRNAs in the hotspots and the lncRNAs, nor did we observe a significant enrichment of regulatory elements in these hotspots. While we could not pinpoint the key factors regulating lncRNA expression, our results suggest that the regulation of lncRNAs involves more complex mechanisms.

CONCLUSION

Our findings provide insights into several features and potential functions of lncRNAs in various tissues. However, the mechanisms by which lncRNA eQTLs regulate lncRNA expression remain unclear. Further research is needed to explore the regulation of lncRNA expression and the mechanisms underlying lncRNA interactions with small molecules and regulatory proteins.

RNA sample optimization for cryo-EM analysis

RNAs play critical roles in most biological processes. Although the three-dimensional (3D) structures of RNAs primarily determine their functions, it remains challenging to experimentally determine these 3D structures due to their conformational heterogeneity and intrinsic dynamics. Cryogenic electron microscopy (cryo-EM) has recently played an emerging role in resolving dynamic conformational changes and understanding structure-function relationships of RNAs including ribozymes, riboswitches and bacterial and viral noncoding RNAs. A variety of methods and pipelines have been developed to facilitate cryo-EM structure determination of challenging RNA targets with small molecular weights at subnanometer to near-atomic resolutions. While a wide range of conditions have been used to prepare RNAs for cryo-EM analysis, correlations between the variables in these conditions and cryo-EM visualizations and reconstructions remain underexplored, which continue to hinder optimizations of RNA samples for high-resolution cryo-EM structure determination. Here we present a protocol that describes rigorous screenings and iterative optimizations of RNA preparation conditions that facilitate cryo-EM structure determination, supplemented by cryo-EM data processing pipelines that resolve RNA dynamics and conformational changes and RNA modeling algorithms that generate atomic coordinates based on moderate- to high-resolution cryo-EM density maps. The current protocol is designed for users with basic skills and experience in RNA biochemistry, cryo-EM and RNA modeling. The expected time to carry out this protocol may range from 3 days to more than 3 weeks, depending on the many variables described in the protocol. For particularly challenging RNA targets, this protocol could also serve as a starting point for further optimizations.

Identification and comparison of exosomal and non-exosomal microRNAs in mantle tissue of Pinctada fucata (Akoya pearl oyster)

MicroRNAs (miRNA) are a class of endogenous non-coding small RNA molecules that are widely found in tissues, biological fluids, and vesicles such as exosomes. Exosomes are extracellular vesicles released from multivesicular bodies of various cell types. They are involved in intercellular communication and transport and immune regulation and may serve as potential biomarkers for diagnosis and monitoring. The function of exosomal miRNAs and their potential applications as biomarkers are a topic of interest. However, identification and comparison of miRNA expression in different biological sample types have rarely been studied. Therefore, in this study, the miRNA profiles of tissue- and tissue-derived exosomes of Pinctada fucata were characterized and compared to screen for differentially expressed miRNAs. The miRNAs functioned within tissues and were also packaged into exosomes. Simultaneously, some miRNAs were preferentially exported to exosomes for their biological functions. Functional analyses suggested that the predicted genes targeted by these differentially expressed miRNAs were extensively involved in intracellular vesicle trafficking and vesicle-mediated substrate transport. Overall, our findings provide insights into the roles of tissue-derived miRNAs and circulating exosomal miRNAs in cell communication and gene regulation. Moreover, this study serves as an additional reference for sample type selection for P. fucata small RNA analysis.

Screening and transcriptomic analysis of anti-Sporothrix globosa targeting AbaA

Introduction

Sporotrichosis is a fungal disease caused by a complex of Sporothrix schenckii, leading to chronic infections of the epidermis and subcutaneous tissue in both humans and animals.

Methods

Through virtual screening targeting the key gene abaA to screen out the small-molecule drugs to treat Sporotrichosis. To further validate the antifungal activity of small-molecule drugs, growth curves, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC) for Sporothrix globosa (S. globosa) and Sporothrix schenckii (S. schenckii) were measured. In addition, we have done animal experiments to explore the function of the drugs. At the same time, qRT-PCR and transcriptome were used to verify the important role of abaA gene in Sporothrix.

Results

Azelastine and Mefloquine effectively inhibit S. globosa and S. schenckii. MBC, and MIC for S. globosa and S. schenckii confirmed that both Azelastine and Mefloquine inhibited the growth of S. globosa and S. schenckii. Additionally, animal experiments demonstrated that Azelastine and Mefloquine reduced skin lesions in mice; post-treatment observations revealed improvements in inflammatory infiltration and granuloma formation. Through transcriptome analysis and qRT-PCR for validation, our findings demonstrate that the abaA gene plays a crucial role in regulating the attachment of the Sporothrix cell wall to the host matrix and in melanin regulation. Notably, when the abaA gene was inhibited, there was a marked increase in the expression of repair genes. These results emphasize the significance of the abaA gene in the biology of Sporothrix.

Discussion

Two small-molecule drugs exhibit the ability to inhibit Sporothrix and treat sporotrichosis both in vitro and in murine models, suggesting their potential for development as therapeutic agents for sporotrichosis. And qRT-PCR and transcriptome results underscore the significance of the abaA gene in Sporothrix. Our results lay the foundation for the search for new treatments for other mycosis.

A divide-and-conquer approach based on deep learning for long RNA secondary structure prediction: Focus on pseudoknots identification

The accurate prediction of RNA secondary structure, and pseudoknots in particular, is of great importance in understanding the functions of RNAs since they give insights into their folding in three-dimensional space. However, existing approaches often face computational challenges or lack precision when dealing with long RNA sequences and/or pseudoknots. To address this, we propose a divide-and-conquer method based on deep learning, called DivideFold, for predicting the secondary structures including pseudoknots of long RNAs. Our approach is able to scale to long RNAs by recursively partitioning sequences into smaller fragments until they can be managed by an existing model able to predict RNA secondary structure including pseudoknots. We show that our approach exhibits superior performance compared to state-of-the-art methods for pseudoknot prediction and secondary structure prediction including pseudoknots for long RNAs. The source code of DivideFold, along with all the datasets used in this study, is accessible at https://evryrna.ibisc.univ-evry.fr/evryrna/dividefold/home.

Symmetric adenine methylation is an essential DNA modification in the early-diverging fungus Rhizopus microsporus

The discovery of N6-methyladenine (6mA) in eukaryotic genomes, typically found in prokaryotic DNA, has revolutionized epigenetics. Here, we show that symmetric 6mA is essential in the early diverging fungus Rhizopus microsporus, as the absence of the MT-A70 complex (MTA1c) responsible for this modification results in a lethal phenotype. 6mA is present in 70% of the genes, correlating with the presence of H3K4me3 and H2A.Z in open euchromatic regions. This modification is found predominantly in nucleosome linker regions, influencing the nucleosome positioning around the transcription start sites of highly expressed genes. Controlled downregulation of MTA1c reduces symmetric 6mA sites affecting nucleosome positioning and histone modifications, leading to altered gene expression, which is likely the cause of the severe phenotypic changes observed. Our study highlights the indispensable role of the DNA 6mA in a multicellular organism and delineates the mechanisms through which this epigenetic mark regulates gene expression in a eukaryotic genome.

Duckweed genomes and epigenomes underlie triploid hybridization and clonal reproduction

The Lemnaceae (duckweeds) are the world's smallest but fastest-growing flowering plants. Prolific clonal propagation facilitates continuous micro-cropping for plant-based protein and starch production and holds tremendous promise for sequestration of atmospheric CO2. Here, we present chromosomal assemblies, annotations, and phylogenomic analysis of Lemna genomes that uncover candidate genes responsible for the unique metabolic and developmental traits of the family, such as anatomical reduction, adaxial stomata, lack of stomatal closure, and carbon sequestration via crystalline calcium oxalate. Lemnaceae have selectively lost genes required for RNA interference, including Argonaute genes required for reproductive isolation (the triploid block) and haploid gamete formation. Triploid hybrids arise commonly among Lemna, and we have found mutations in highly conserved meiotic crossover genes that could support polyploid meiosis. Further, mapping centromeres by chromatin immunoprecipitation suggests their epigenetic origin despite divergence of underlying tandem repeats and centromeric retrotransposons. Syntenic comparisons with Wolffia and Spirodela reveal that diversification of these genera coincided with the "Azolla event" in the mid-Eocene, during which aquatic macrophytes reduced high atmospheric CO2 levels to those of the current ice age. Facile regeneration of transgenic fronds from tissue culture, aided by reduced epigenetic silencing, makes Lemna a powerful biotechnological platform, as exemplified by recent engineering of high-oil Lemna that outperforms oil-seed crops.

High-Quality Genome Assembly and Transcriptome of Rhododendron platypodum Provide Insights into Its Evolution and Heat Stress Response

R. platypodum (Rhododendron platypodum) is an endangered alpine species with a highly restricted distribution in the southwestern region of China, which possesses significant ornamental and horticultural value. In this study, the high-quality genome assembly of R. platypodum at the chromosomal level is reported. The total genome size was determined to be 642.25 Mb, with a contig N50 of 25.64 Mb, and it contains 36,522 predicted genes. Comparative genomic analysis between R. platypodum and other species revealed the expansion of gene families, such as those related to transition metal ion binding and sodium ion transport, as well as the contraction of gene families involved in the recognition of pollen and pollen-pistil interaction. These findings might explain the adaptation of R. platypodum to rocky habitats and contribute to its endangered status. Furthermore, a heat stress experiment was conducted on R. platypodum, followed by transcriptome sequencing and physiological co-analysis to construct a co-expression network. This analysis identified the candidate gene TAR1-A and other transcription factors exhibiting differential expression under heat stress. The whole-genome sequencing, transcriptome analysis, and physiological co-analysis of R. platypodum provide valuable resources for its conservation and offer insights into its mechanisms of heat stress.

A conserved terpene cyclase gene in Sanghuangporus for abscisic acid-related sesquiterpenoid biosynthesis

BACKGROUND

The medicinal mushroom Sanghuangporus is renowned in East Asia for its potent therapeutic properties, attributed in part to its bioactive sesquiterpenoids. However, despite their recognized medicinal potential, the biosynthetic pathways and specific enzymes responsible for sesquiterpenoid production in Sanghuangporus remain unexplored, limiting opportunities to optimize their medicinal applications.

RESULTS

Sesquiterpenoids from four Sanghuangporus species were extracted through targeted isolation using mass spectrometry (MS)-based metabolomics, resulting in the discovery of six known abscisic acid-related compounds and one new compound, whose structure was determined through spectroscopic and computational analysis. We employed a natural product genome mining approach to identify a putative biosynthetic gene cluster (BGC) containing a sesquiterpene synthase gene, ancA, associated with the detected compounds. Biosynthetic pathways for these compounds were proposed based on an integrative approach combining BGC analysis and MS2 fragment-based dereplication. Further analyses revealed that the gene content and synteny of the ancA BGC are relatively well-conserved across Sanghuangporus species but less so outside the genus.

CONCLUSIONS

A sesquiterpene synthase gene, its associated BGC, and the biosynthetic pathway for a group of detected abscisic acid-related sesquiterpenoids in Sanghuangporus were predicted through genomic and metabolic data analyses. This study addresses a critical gap in understanding the genetic basis of sesquiterpenoid production in Sanghuangporus and offers insights for future research on engineering metabolic pathways to enhance sesquiterpenoid production for medicinal use.

Reprogramming site-specific retrotransposon activity to new DNA sites

Retroelements have a critical role in shaping eukaryotic genomes. For instance, site-specific non-long terminal repeat retrotransposons have spread widely through preferential integration into repetitive genomic sequences, such as microsatellite regions and ribosomal DNA genes1-6. Despite the widespread occurrence of these systems, their targeting constraints remain unclear. Here we use a computational pipeline to discover multiple new site-specific retrotransposon families, profile members both biochemically and in mammalian cells, find previously undescribed insertion preferences and chart potential evolutionary paths for retrotransposon retargeting. We identify R2Tg, an R2 retrotransposon from the zebra finch, Taeniopygia guttata, as an orthologue that can be retargeted by payload engineering for target cleavage, reverse transcription and scarless insertion of heterologous payloads at new genomic sites. We enhance this activity by fusing R2Tg to CRISPR-Cas9 nickases for efficient insertion at new genomic sites. Through further screening of R2 orthologues, we select an orthologue, R2Tocc, with natural reprogrammability and minimal insertion at its natural 28S site, to engineer SpCas9H840A-R2Tocc, a system we name site-specific target-primed insertion through targeted CRISPR homing of retroelements (STITCHR). STITCHR enables the scarless, efficient installation of edits, ranging from a single base to 12.7 kilobases, gene replacement and use of in vitro transcribed or synthetic RNA templates. Inspired by the prevalence of nLTR retrotransposons across eukaryotic genomes, we anticipate that STITCHR will serve as a platform for scarless programmable integration in dividing and non-dividing cells, with both research and therapeutic applications.

Chromosome-level genome assembly of the traditional medicinal plant Lindera aggregata

Lindera aggregata is a renowned medicinal plant in China, particularly the variety from Tiantai, Zhejiang Province, which is esteemed for its superior medicinal properties. Beyond its medicinal value, it holds significant economic potential and phylogenetic significance. Utilizing a range of sequencing techniques, we have successfully assembled and annotated a high-quality chromosome-level genome of L. aggregata. The assembled genome spans approximately 1.59 Gb, with a scaffold N50 length of 132.62 Mb. Approximately 93.07% of the assembled sequences have been anchored to 12 pseudo-chromosomes, and 70.02% of the genome consists of repetitive sequences. According to the annotations, a total of 33,283 genes are identified, of which 96.95% can predict function. This high-quality chromosome-level assembly and annotation will greatly assist in the development and utilization of L. aggregata's valuable resources, and also provide a crucial molecular foundation for investigating the evolutionary relationships within the Lauraceae family and the mechanisms behind the synthesis of active ingredients in L. aggregata.

Reprogrammable RNA-targeting CRISPR systems evolved from RNA toxin-antitoxins

Despite ongoing efforts to study CRISPR systems, the evolutionary origins giving rise to reprogrammable RNA-guided mechanisms remain poorly understood. Here, we describe an integrated sequence/structure evolutionary tracing approach to identify the ancestors of the RNA-targeting CRISPR-Cas13 system. We find that Cas13 likely evolved from AbiF, which is encoded by an abortive infection-linked gene that is stably associated with a conserved non-coding RNA (ncRNA). We further characterize a miniature Cas13, classified here as Cas13e, which serves as an evolutionary intermediate between AbiF and other known Cas13s. Despite this relationship, we show that their functions substantially differ. Whereas Cas13e is an RNA-guided RNA-targeting system, AbiF is a toxin-antitoxin (TA) system with an RNA antitoxin. We solve the structure of AbiF using cryoelectron microscopy (cryo-EM), revealing basic structural alterations that set Cas13s apart from AbiF. Finally, we map the key structural changes that enabled a non-guided TA system to evolve into an RNA-guided CRISPR system.

A telomere-to-telomere genome assembly of cotton provides insights into centromere evolution and short-season adaptation

Cotton (Gossypium hirsutum L.) is a key allopolyploid crop with global economic importance. Here we present a telomere-to-telomere assembly of the elite variety Zhongmian 113. Leveraging technologies including PacBio HiFi, Oxford Nanopore Technology (ONT) ultralong-read sequencing and Hi-C, our assembly surpasses previous genomes in contiguity and completeness, resolving 26 centromeric and 52 telomeric regions, 5S rDNA clusters and nucleolar organizer regions. A phylogenetically recent centromere repositioning on chromosome D08 was discovered specific to G. hirsutum, involving deactivation of an ancestral centromere and the formation of a unique, satellite repeat-based centromere. Genomic analyses evaluated favorable allele aggregation for key agronomic traits and uncovered an early-maturing haplotype derived from an 11 Mb pericentric inversion that evolved early during G. hirsutum domestication. Our study sheds light on the genomic origins of short-season adaptation, potentially involving introgression of an inversion from primitively domesticated forms, followed by subsequent haplotype differentiation in modern breeding programs.

Deep learning for RNA structure prediction

Predicting RNA structures from sequences with computational approaches is of vital importance in RNA biology considering the high costs of experimental determination. AI methods have revolutionized this field in recent years, enabling RNA structure prediction with increasingly higher accuracy and efficiency. With an increase in the number of models proposed for this task, this review presents a timely summary of the applications of AI, particularly deep learning, in RNA structure prediction, highlighting their methodology advances as well as the challenges and opportunities for further work in this field.

An chromosome-level haplotype-resolved genome assembly and annotation of pitaya (Selenicereus polyrhizus)

Pitaya, (Selenicereus spp.), a fruit originating from North and Central America and extensively cultivated in China and Vietnam, holds significant economic value. Utilizing PacBio HiFi sequencing and Oxford Nanopore Technologies ultra-long sequencing, aided by Hi-C data, we have assembled a chromosome-level haplotype-resolved genome. The sizes of the two haplotype genomes were determined to be 1.477 Gb (hap1, contig N50 = 133.35 Mb) and 1.442 Gb (hap2, contig N50 = 132.57 Mb), with 96.7% (hap1) and 98.4% (hap2) respectively allocated to 11 pseudochromosomes. Hap1 comprises 58.94% repeat sequences and predicts a total of 29,139 protein-coding gene models and 18,378 non-coding RNAs. Hap2 comprises 58.37% repeat sequences and predicts a total of 28,538 protein-coding gene models and 19,458 non-coding RNAs. Notably, 93.5% and 93.6% of protein-coding genes were annotated for the two haplotypes. The high-quality genome assembly presented in this study provides a valuable resource for future ecological, evolutionary, biological, and breeding research in pitaya.

Haplotype-resolved genome assembly of the tetraploid Youcha tree Camellia meiocarpa Hu

Camellia meiocarpa Hu, a member of Youcha species in the genus Camellia, is an important woody edible Youcha plant with high ecological and economic value. The haplotype-resolved genome assembly of this tetraploid species can shed light on genomic evolution and the functional divergence among subgenomes and haplotypes. In this study, we achieved the first chromosome-level haplotype-resolved genome assembly using PacBio HiFi, Hi-C, and Illumina sequencing. The scaffolds, with an N50 of 44.46 Mb and 41.40 Mb, were mapped to 60 chromosomes and four distinct haplotypes, each with unique transposon features. The haplotypes varied in length (2967.25 Mb to 3041.66 Mb) and contained 51,336 to 52,631 protein-coding genes, 99.4% of which were annotated. Non-coding RNAs and repetitive elements were identified across haplotypes. This comprehensive genomic resource will enhance molecular and genetic studies, aiding in the conservation and utilization of Youcha.

Non-coding RNAs: the architects of placental development and pregnancy success

Noncoding RNAs (ncRNAs) constitute a significant portion of the transcriptome that lacks evident protein-coding functions; however, they have been confirmed to be crucial in various biological processes, including placental development. Notwithstanding the existence of various ncRNAs, research on their role in placental development and pregnancy has been constrained. The predominant category of identified ncRNAs specific to placental tissue is microRNAs (miRNAs). Given their prevalence, the significantly larger cohort of other non-coding RNAs, such as circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs), is anticipated to exert a considerably greater influence than miRNAs. Syncytiotrophoblast, a fetal-derived cell, serves as a conduit between the fetus and mother by secreting extracellular vesicles that contain fetal proteins and RNA. Alterations in ncRNAs within placental tissue, especially in trophoblast cells and extracellular vesicles, may be linked to placental dysfunction that leads to pregnancy complications, serving either as a causative factor or a result. This review encapsulates the existing understanding of ncRNAs in placental development, pregnancy success, pregnancy-related complications, extracellular vesicle conveyance, and their capacity as innovative diagnostic instruments and therapeutic strategies.

TTLOC: A Tn5 transposase-based approach to localize T-DNA integration sites

Thermal asymmetric interlaced-polymerase chain reaction-based and whole-genome sequencing-based T-DNA localization approaches have been developed for the recovery of T-DNA integration sites (TISs). Nevertheless, a low-cost and high-throughput technique for the detection of TISs, which would facilitate the identification of genetically engineered plants, is in high demand for rapid crop breeding and plant synthetic biology. Here, we present Tn5 transposase-based T-DNA integration site localization (TTLOC), a Tn5-based approach for TIS localization. TTLOC employs specialized adaptor-assembled Tn5 transposases for genomic DNA tagmentation. TTLOC library construction is straightforward, involving only six steps that requires two and a half hours to complete. The resulting pooled library is compatible with next-generation sequencing, which enables high-throughput determination. We demonstrate the ability of TTLOC to recover 95 non-redundant TISs from 65 transgenic Arabidopsis (Arabidopsis thaliana) lines, and 37 non-redundant TISs from the genomes of transgenic rice (Oryza sativa), soybean (Glycine max), tomato (Solanum lycopersicum), potato (Solanum tuberosum), and from the large hexaploid wheat (Triticum aestivum) genome. TTLOC is a cost-effective method, as 1 to 2 Gb of raw data for each multiplexing library are sufficient for efficient TIS calling, independent of the genome size. Our results establish TTLOC as a promising strategy for evaluation of genome engineered plants and for selecting genome safe harbors for trait stacking in crop breeding and plant synthetic biology.

Transcriptomics in the era of long-read sequencing

Transcriptome sequencing revolutionized the analysis of gene expression, providing an unbiased approach to gene detection and quantification that enabled the discovery of novel isoforms, alternative splicing events and fusion transcripts. However, although short-read sequencing technologies have surpassed the limited dynamic range of previous technologies such as microarrays, they have limitations, for example, in resolving full-length transcripts and complex isoforms. Over the past 5 years, long-read sequencing technologies have matured considerably, with improvements in instrumentation and analytical methods, enabling their application to RNA sequencing (RNA-seq). Benchmarking studies are beginning to identify the strengths and limitations of long-read RNA-seq, although there remains a need for comprehensive resources to guide newcomers through the intricacies of this approach. In this Review, we provide a comprehensive overview of the long-read RNA-seq workflow, from library preparation and sequencing challenges to core data processing, downstream analyses and emerging developments. We present an extensive inventory of experimental and analytical methods and discuss current challenges and prospects.

Discovery of Arbuscular Mycorrhizae in Mosses of the Pottiaceae Family from the Chaco Serrano (Tucumán, Argentina)

Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi that associate with the vast majority of terrestrial plants. Among non-vascular plants, while AMF associations are well-documented in liverworts and hornworts, there is a broad consensus that symbiotic associations do not occur in mosses. Here, we report the presence of AMF in the living material of mosses found in Chaco Serrano (Tucumán, Argentina). We found all characteristic structures of AMF when establishing an intimate connection with two moss species of Pottiaceae (Bryophyta). While Gertrudiella uncinicoma exhibited AMF with both Arum- and Paris-type morphologies, Pleurochaete luteola only displayed an Arum-type morphology. Plant tissue samples were subjected to high-throughput sequencing for AMF identification. We determined that Rhizophagus irregularis was a clear dominant species in both moss species, with Glomus sp. also being present as a less abundant element. In addition, we also reported the presence of vesicles, arbuscules, and spores adhered to the hyphae and the presence of septate endophytes. This finding expands our understanding of the interactions between AMF and non-vascular plants and prompt us to further characterize this interaction by considering the diversity of mycorrhizal associations with concurrent implications for the ecology of mosses and the functionality of the ecosystems.

TetraRNA, a tetra-class machine learning model for deciphering the coding potential derivation of RNA world

CncRNAs (coding and noncoding RNAs) are a class of bifunctional RNAs that that has both coding and noncoding biological activity. An increasing number of cncRNAs are being identified, prompting reassessment of our knowledge of RNA. However, most existing RNA classification tools are based on binary classification models which are not effective in distinguishing cncRNAs from mRNAs or long noncoding RNAs (lncRNAs). Our statistical analysis demonstrated that mRNA-derived cncRNAs (untranslated mRNAs, untr-mRNAs) and lncRNA-derived cncRNAs (translated ncRNAs, tr-ncRNAs) do not fall in the same cluster. Therefore, in this study, we devised a novel tetra-class RNA classification model that is systematically optimized for RNA feature extraction. According to our model, all human RNAs can be reclassified into one of four categories - mRNA, untr-mRNA, lncRNA, and tr-ncRNA - representing a novel RNA classification system and allowing the discovery of more potential cncRNAs. Further analysis revealed significant differences among the four types of RNAs in tissue-specific expression, functional annotation, sequence composition, and other factors, providing insights into their divergent evolution trajectories. Moreover, investigation of the small tr-ncRNA peptides demonstrated that their evolution is coordinated with that of the the conserved functional small RNAs associated with them. All analysis results have been integrated into a database - TetraRNADB accessible online (http://tetrarnadb.liu-lab.com/).

The Three-Dimensional Structure of the Genome of the Dark Septate Endophyte Exophiala tremulae and Its Symbiosis Effect on Alpine Meadow Plant Growth

The establishment of artificial grassland is a good pathway for resolving serious social and economic problems in the Qinghai-Tibet Plateau. Some beneficial indigenous microbes may be used to improve productivity in artificial grassland. The genome of the indigenous dark septate fungus, Exophiala tremulae CICC2537, was sequenced and assembled at the chromosome level using the PacBio sequencing platform, with the assistance of the Hi-C technique for scaffolding, and its 3D genome structures were investigated. The genome size of E. tremulae is 51.903848 Mb, and it contains eight chromosomes. A total of 12,277 protein-coding genes were predicted, and 11,932 genes (97.19%) were annotated. As for the distribution of exon and intron number and the distribution of gene GC and CDS GC, E. tremulae showed similar distribution patterns to the other investigated members of the genus Exophiala. The analysis of carbohydrate-active enzymes showed that E. tremulae possesses the greatest number of enzymes with auxiliary activities and the lowest number of enzymes with carbohydrate-binding modules among the investigated fungi. The total number of candidate effector proteins was 3337, out of which cytoplasmic and apoplastic effector proteins made up 3100 and 163, respectively. The whole genome of E. tremulae contained 40 compartment As and 76 compartment Bs, and there was no significant difference in GC content in its compartment As and Bs. The whole genome of E. tremulae was predicted to contain 155 topologically associating domains (TADs), and their average length was 250,000 bp, but there were no significant differences in the numbers of genes and the GC content per bin localized within the boundaries and interiors of TADs. Comparative genome analysis showed that E. tremulae diverged from Exophiala mesophila about 34.1 (30.0-39.1) Myr ago, and from Exophiala calicioides about 85.6 (76.1-90.6) Myr ago. Compared with all the investigated fungi, the numbers of contraction and expansion gene families in the E. tremulae genome were 13 and 89, respectively, and the numbers of contraction and expansion genes were 14 and 670, respectively. Our work provides a basis for the use of the dark septate fungus in alpine artificial grassland and further research into its symbiosis mechanisms, which may improve the growth of plant species used in the Qinghai-Tibet Plateau.

Chromosome-level genome assembly and annotation of the White-spotted spinefoot Siganus canaliculatus

The White-spotted spinefoot S. canaliculatus, is an economically important marine fish in South China and featured by possessing poisonous glands in its fin spines. However, the unavailability of the S. canaliculatus genome has been a serious obstacle to genetic breeding as well as basic researches such as uncovering genomic basis underlying its toxigenic glands. Here, we presented a chromosome-level genome assembly coupled with good annotation of S. canaliculatus using multiple omics technologies. The assembled genome size was 547.39 Mb, with a contig N50 and scaffold N50 length of 21.41 Mb and 21.79 Mb, respectively. Approximately 95.32% (521.76 Mb) of assembled sequences were placed into 24 pseudochromosomes with the support of Hi-C contact map. Furthermore, around 16.37% of the genome was composed of repetitive elements. The quality of the assembly assessed using BUSCO showed that 98.6% of BUSCO genes were identified as complete. 25,323 protein-coding genes were predicted after integration of three kinds of evidence, of which 96.96% were functionally annotated in at least one of nine protein databases. In sum, the chromosome-level genome assembly and annotation provide fundamental resources for genetic breeding and molecular mechanism related studies of S. canaliculatus.

Metatranscriptomic analysis reveals gut microbiome bacterial genes in pyruvate and amino acid metabolism associated with hyperuricemia and gout in humans

Several pathologies with metabolic origin, such as hyperuricemia and gout, have been associated with the gut microbiota taxonomic profile. However, there is no evidence of which bacterial genes are being expressed in the gut microbiome, and of their potential effects on hyperuricemia and gout. We sequenced the RNA of 26 fecal samples from 10 healthy normouricemic controls, 10 with asymptomatic hyperuricemia (AH), and six gout patients. The coding sequences were mapped to KEGG orthologues (KO). We compared the expression levels using generalized linear models and validated the expression of four KO in a larger sample by qRT-PCR. A distinct genetic expression pattern was identified among groups. AH individuals and gout patients showed an over-expression of KOs mainly related to pyruvate metabolism (Log2foldchange > 23, p-adj ≤ 3.56 × 10- 9), the pentose pathway (Log2foldchange > 24, p-adj < 1.10 × 10-12) and purine metabolism (Log2foldchange > 22, p-adj < 1.25 × 10- 7). AH subjects had lower expression of KO related to glycine metabolism (Log2foldchange=-18, p-adj < 1.72 × 10-6) than controls. Gout patients had lower expression (Log2foldchange=-22.42, p-adj < 3.31 × 10- 16) of a KO involved in phenylalanine biosynthesis, in comparison to controls and AH subjects. The over-expression seen for the KO related to pyruvate metabolism and the pentose pathway in gout patients´ microbiome was validated. There is a differential gene expression pattern in the gut microbiome of normouricemic individuals, AH subjects and gout patients. These differences are mainly located in metabolic pathways involved in acetate precursors and bioavailability of amino acids.

Small nucleolar RNAs promote the restoration of muscle differentiation defects in cells from myotonic dystrophy type 1

Recently, the repertoire of human small nucleolar noncoding RNAs (snoRNAs) and their potential functions has expanded with the discovery of new snoRNAs and messenger RNA (mRNA) targets, for which snoRNA-guided modifications may influence their stability, translatability, and splicing. We previously identified snoRNAs that are abundant in healthy human muscle progenitor cells. In this study, we demonstrated that SNORA40 and SNORA70 loss-of-function impairs myogenic differentiation. Interestingly, gain-of-function can rescue impaired differentiation muscle progenitor cells in myotonic dystrophy type 1 (DM1). We identified cyclin D3 (CCND3) mRNA, which is partially located in the nucleolus, as a target for SNORA40 and SNORA70, which are required for its pseudouridylated status. Expression of the CCND3 protein is required for muscle progenitors to exit the cell-cycle when they are induced to differentiate. We revealed that this switch requires SNORA40/70. Finally, we observed that DM1 cells show reduced levels of SNORA40/70 and undetectable CCND3 protein. However, restoring normal levels of SNORA40/70 partially restored CCND3 protein expression, coinciding with improved cell fusion capacity in DM1 muscle progenitors. Collectively, these data suggest that this effect may stem from SNORA40/70-dependent pseudouridylation of CCND3 mRNA, emphasizing snoRNAs as key players in normal and pathological muscle differentiation.

DRLiPS: a novel method for prediction of druggable RNA-small molecule binding pockets using machine learning

Ribonucleic Acid (RNA) is the central conduit for information transfer in the cell. Identifying potential RNA targets in disease conditions is a challenging task, given the vast repertoire of functional non-coding RNAs in a human cell. A potential druggable target must satisfy several criteria, including disease association, cellular accessibility, binding pockets for drug-like molecules, and minimal cross-reactivity. While several methods exist for prediction of druggable proteins, they cannot be repurposed for RNAs due to fundamental differences in their binding modality. Taking all these constraints into account, a new structure-based model, Druggable RNA-Ligand binding Pocket Selector (DRLiPS), is developed here to predict binding site-level druggability of any given RNA target. A novel strategy for sampling negative binding sites in RNA structures using three parallel approaches is demonstrated here to improve model specificity: backbone motif search, exhaustive pocket prediction, and blind docking. An external blind test dataset has also been curated to showcase the model's generalizability to both experimental and modelled apo state RNA structures. DRLiPS has achieved an F1-score of 0.70, precision of 0.61, specificity of 0.89, and recall of 0.73 on this external test dataset, outperforming two existing methods, DrugPred_RNA and RNACavityMiner. Further analysis indicates that the features selected for model-building generalize well to both apo and holo states with a backbone RMSD tolerance of 3 Å. It can also predict the effect of binding site single point mutations on druggability, which can aid in optimizing synthetic RNA aptamers for small molecule recognition. The DRLiPS model is freely accessible at https://web.iitm.ac.in/bioinfo2/DRLiPS/.

A telomere-to-telomere genome assembly of Chinese grain sorghum 654

The grain sorghum inbred line 654 serves as a parent for numerous Chinese commercial hybrids and recombinant inbred lines (RILs), which have played a pivotal role in the cloning of several agronomically important traits. In this study, we present a telomere-to-telomere (T2T) genome assembly of the inbred line 654 (728.81 Mb) using PacBio HiFi, ultra-long Oxford Nanopore Technology, and Hi-C sequencing data. The T2T genome assembly has high integrity (contains all of 10 centromeres and 20 telomeres without any gaps), high contiguity (contig N90: 52.02 Mb), high completeness (98.33% BUSCO completeness, 98.88% k-mer completeness, and LAI 24.38), and extremely low base error (3.37 × 10-7, QV: 64.72). A total of 62.34% sequences were identified as repetitive, and rest region contained 44,399 protein-coding genes, of which 30,245 were functionally annotated. The gap-free T2T genome assembly enables the full picture of the potential translational genomics, and provides the highest resolution genetic map for future studies on genome evolution, structure variation, and the genetic control of agronomic traits in sorghum breeding.

Insights into dill (Anethum graveolens) flavor formation via integrative analysis of chromosomal-scale genome, metabolome and transcriptome

INTRODUCTION

Dill (Anethum graveolens) is a significant medicinal herb belonging to the Apiaceae family. Owing to its high levels of volatile organic compounds (VOCs), dill is commonly utilized for essential oil extraction and medicine purpose. However, the biosynthesis of the crucial VOC in dill remains obscure.

OBJECTIVES

Identify the key VOCs related to the flavor formation in dill and dissect the regulatory mechanism of their synthesis.

METHODS

The dill chromosomal-level genome was constructed by PacBio HiFi, Hi-C, and BGISEQ second generation sequencing and assembly. The VOCs in dill leaves were identified through GC-MS. The potential mechanism involved in regulating the VOC accumulation in dill flavor formation was analyzed by multi-omics analysis.

RESULTS

A 1.17 Gb chromosome-scale genome of dill with a contig N50 of 10.78 Mb was constructed. A total of 46,538 genes were annotated across 11 assembled chromosomes. Comparative genomics analysis suggested that transposable element insertions, especially LTR-Gypsy, have contributed to the evolution and expansion of the dill genome. The flavor formation of dill was mainly attributed to terpenoids, especially α-phellandrene, β-ocimene, and o-cymene. The contribution of expansion and replication of terpenoid synthesis pathway genes, especially terpene synthase (TPS), to the abundant terpenoid production of dill was identified. Differential gene expression patterns observed at various developmental stages and tissues provided key candidate genes for the regulation of terpenoid synthesis, as well as transcription factors. The different accumulation of esters and aromatics also affected the flavor formation of dill. The key genes implicated in the synthesis of anethole, namely AIS and AMT were further identified.

CONCLUSION

This study constructed the chromosome level genome and identified the main VOCs and related key genes in flavor formation of dill, shedding lights on our understanding of terpenoid biosynthesis but also offered guidance for future genetic research on molecular breeding in Anethum graveolens.

Bacterial response to the 2021 Orange County, California, oil spill was episodic but subtle relative to natural fluctuations

An oil spill began in October 2021 off the coast of Orange County, California, releasing 24,696 gallons of crude oil into coastal environments. Although oil spills, such as this one, are recurrent accidents along the California coast, no prior studies have been performed to examine the severity of the local bacterial response. A coastal 10-year time series of short-read metagenomes located within the impacted area allowed us to quantify the magnitude and duration of the disturbance relative to natural fluctuations. We found that the largest change in bacterial beta-diversity occurred at the end of October. The change in taxonomic beta-diversity corresponded with an increase in the sulfur-oxidizing clade Candidatus Thioglobus, an increase in the total relative abundance of potential hydrocarbon-degrading bacteria, and an anomalous decline in the picocyanobacteria Synechococcus. Similarly, changes in function were related to anomalous declines in photosynthetic pathways and anomalous increases in sulfur metabolism pathways as well as aromatic degradation pathways. There was a lagged response in taxonomy and function to peaks in total PAHs. One week after peaks in total PAH concentrations, the largest shifts in taxonomy were observed, and 1 week after the taxonomy shifts were observed, unique functional changes were seen. This response pattern was observed twice during our sampling period, corresponding with the combined effect of resuspended PAHs and increased nutrient concentrations due to physical transport events. Thus, the impact of the spill on bacterial communities was temporally extended and demonstrates the need for continued monitoring for longer than 3 months after initial oil exposure.IMPORTANCEOil spills are common occurrences in waterways, releasing contaminants into the aquatic environment that persist for long periods of time. Bacterial communities are rapid responders to environmental disturbances, such as oil spills. Within bacterial communities, some members will be susceptible to the disturbance caused by crude oil components and will decline in abundance, whereas others will be opportunistic and will be able to use crude oil components for their metabolism. In many cases, when an oil spill occurs, it is difficult to assess the oil spill's impact because no samples were collected prior to the accident. Here, we examined the bacterial response to the 2021 Orange County oil spill using a 10-year time series that lies within the impacted area. The results presented here are significant because (i) susceptible and opportunistic taxa to oil spills within the coastal California environment are identified and (ii) the magnitude and duration of the in situ bacterial response is quantified for the first time.

Chromosome-level genome assembly of the clam, Xishi tongue Coelomactra antiquata

Xishi tongue (Coelomactra antiquata), a commercially valuable marine bivalve, is distributed along the coastal waters of East Asia. In China, significant morphological and genetic differences have been observed between northern and southern populations. Overfishing and pollution have caused a severe decline in its natural populations, rendering the species endangered. In this study, we constructed the first chromosome-level genome of C. antiquata based on PacBio HiFi and Hi-C sequencing data. The assembled genome was 791.83 Mb in size, with the scaffold N50 of 44.05 Mb, and 99.79% of the sequences (790.13 Mb) were anchored to 19 chromosomes. A total of 24,592 protein-coding genes were predicted in the final assembly, of which 89.88% were functionally annotated. The BUSCO analysis revealed a genome completeness of 97.69%. The high-quality genome serves as a critical resource for advancing research on population genetics and germplasm conservation of this commercial shellfish, thereby facilitating sustainable management and conservation efforts.

Genomic investigation of benthic invertebrates from the Clarion-Clipperton fields of polymetallic nodules

The abyssal plains of the Clarion-Clipperton Zone (CCZ) are famous for their fields of polymetallic nodules, which are inhabited by benthic invertebrates. Ten specimens from the Interoceanmetal Joint Organisation (IOM) licence area in the CCZ were collected in 2014 and submitted to a short-read genome skimming sequencing. In total, mitochondrial genomes and nuclear ribosomal genes were retrieved for nine different organisms belonging to Ophiuroidea, Holothuroidea, Polychaeta, Bryozoa, Porifera, and Brachiopoda (assigned to these phyla immediately upon retrieval from the seafloor). As many of these samples were partial and physically deteriorated following their seven-year storage in IOM's collections, their morphology-based taxonomic identification could rarely be performed at the lowest possible level (species or genus) prior to preparing the samples for molecular or genomic investigations. Therefore, it was not possible to apply the reverse identification scheme recommended for such investigations. However, several of these specimens represent poorly studied groups for which few molecular references are available as of now. In two cases, the presence of introns in the mitochondrial genome questions the practicability of using the cox1 gene for further routine molecular barcoding of these organisms. These results might be useful in future DNA primers design, molecular barcoding, and phylogeny or population genetic studies when more samples are obtained.

Rare pathogenic structural variants show potential to enhance prostate cancer germline testing for African men

Prostate cancer (PCa) is highly heritable, with men of African ancestry at greatest risk and associated lethality. Lack of representation in genomic data means germline testing guidelines exclude for Africans. Established that structural variations (SVs) are major contributors to human disease and prostate tumourigenesis, their role is under-appreciated in familial and therapeutic testing. Utilising clinico-methodologically matched deep-sequenced whole-genome data for 113 African versus 57 European PCa patients, we interrogate 42,966 high-quality germline SVs using a best-fit pathogenicity prediction workflow. We identify 15 potentially pathogenic SVs representing 12.4% African and 7.0% European patients, of which 72% and 86% met germline testing standard-of-care recommendations, respectively. Notable African-specific loss-of-function gene candidates include DNA damage repair MLH1 and BARD1 and tumour suppressors FOXP1, WASF1 and RB1. Representing only a fraction of the vast African diaspora, this study raises considerations with respect to the contribution of kilo-to-mega-base rare variants to PCa pathogenicity and African-associated disparity.

Understanding dysbiosis and resilience in the human gut microbiome: biomarkers, interventions, and challenges

The healthy gut microbiome is important in maintaining health and preventing various chronic and metabolic diseases through interactions with the host via different gut-organ axes, such as the gut-brain, gut-liver, gut-immune, and gut-lung axes. The human gut microbiome is relatively stable, yet can be influenced by numerous factors, such as diet, infections, chronic diseases, and medications which may disrupt its composition and function. Therefore, microbial resilience is suggested as one of the key characteristics of a healthy gut microbiome in humans. However, our understanding of its definition and indicators remains unclear due to insufficient experimental data. Here, we review the impact of key drivers including intrinsic and extrinsic factors such as diet and antibiotics on the human gut microbiome. Additionally, we discuss the concept of a resilient gut microbiome and highlight potential biomarkers including diversity indices and some bacterial taxa as recovery-associated bacteria, resistance genes, antimicrobial peptides, and functional flexibility. These biomarkers can facilitate the identification and prediction of healthy and resilient microbiomes, particularly in precision medicine, through diagnostic tools or machine learning approaches especially after antimicrobial medications that may cause stable dysbiosis. Furthermore, we review current nutrition intervention strategies to maximize microbial resilience, the challenges in investigating microbiome resilience, and future directions in this field of research.

Comprehensive benchmarking of large language models for RNA secondary structure prediction

In recent years, inspired by the success of large language models (LLMs) for DNA and proteins, several LLMs for RNA have also been developed. These models take massive RNA datasets as inputs and learn, in a self-supervised way, how to represent each RNA base with a semantically rich numerical vector. This is done under the hypothesis that obtaining high-quality RNA representations can enhance data-costly downstream tasks, such as the fundamental RNA secondary structure prediction problem. However, existing RNA-LLM have not been evaluated for this task in a unified experimental setup. Since they are pretrained models, assessment of their generalization capabilities on new structures is a crucial aspect. Nonetheless, this has been just partially addressed in literature. In this work we present a comprehensive experimental and comparative analysis of pretrained RNA-LLM that have been recently proposed. We evaluate the use of these representations for the secondary structure prediction task with a common deep learning architecture. The RNA-LLM were assessed with increasing generalization difficulty on benchmark datasets. Results showed that two LLMs clearly outperform the other models, and revealed significant challenges for generalization in low-homology scenarios. Moreover, in this study we provide curated benchmark datasets of increasing complexity and a unified experimental setup for this scientific endeavor. Source code and curated benchmark datasets with increasing complexity are available in the repository: https://github.com/sinc-lab/rna-llm-folding/.

NucleoSeeker-precision filtering of RNA databases to curate high-quality datasets

The structural prediction of biomolecules via computational methods complements the often involved wet-lab experiments. Unlike protein structure prediction, RNA structure prediction remains a significant challenge in bioinformatics, primarily due to the scarcity of annotated RNA structure data and its varying quality. Many methods have used this limited data to train deep learning models but redundancy, data leakage and bad data quality hampers their performance. In this work, we present NucleoSeeker, a tool designed to curate high-quality, tailored datasets from the Protein Data Bank (PDB) database. It is a unified framework that combines multiple tools and streamlines an otherwise complicated process of data curation. It offers multiple filters at structure, sequence, and annotation levels, giving researchers full control over data curation. Further, we present several use cases. In particular, we demonstrate how NucleoSeeker allows the creation of a nonredundant RNA structure dataset to assess AlphaFold3's performance for RNA structure prediction. This demonstrates NucleoSeeker's effectiveness in curating valuable nonredundant tailored datasets to both train novel and judge existing methods. NucleoSeeker is very easy to use, highly flexible, and can significantly increase the quality of RNA structure datasets.

Chromosome-level genome assembly of Iodes seguinii and its metabonomic implications for rheumatoid arthritis treatment

Iodes seguinii is a woody vine known for its potential therapeutic applications in treating rheumatoid arthritis (RA) due to its rich bioactive components. Here, we achieved the first chromosome-level assembly of the nuclear genome of I. seguinii using PacBio HiFi and chromatin conformation capture (Hi-C) sequencing data. The initial assembly with PacBio data produced contigs with an N50 length of 9.71 Mb, and Hi-C data anchored these contigs into 13 chromosomes, achieving a total length of 273.58 Mb, closely matching the estimated genome size. Quality assessments, including BUSCO, long terminal repeat assembly index, transcriptome mapping rates, and sequencing coverage, confirmed the high quality, completeness, and continuity of the assembly, identifying 115.28 Mb of repetitive sequences, 1062 RNA genes, and 25,270 protein-coding genes. Additionally, we assembled and annotated the 150,599 bp chloroplast genome using Illumina sequencing data, containing 121 genes including key DNA barcodes, with maturase K (matK) proving effective for species identification. Phylogenetic analysis positioned I. seguinii at the base of the Lamiales clade, identifying significant gene family expansions and contractions, particularly related to secondary metabolite synthesis and DNA damage repair. Metabolite analysis identified 84 active components in I. seguinii, including the discovery of luteolin, with 119 targets predicted for RA treatment, including core targets like AKT1, toll-like receptor 4 (TLR4), epidermal growth factor receptor (EGFR), tumor necrosis factor (TNF), TP53, NFKB1, janus kinase 2 (JAK2), BCL2, mitogen-activated protein kinase 1 (MAPK1), and spleen-associated tyrosine kinase (SYK). Key active components such as flavonoids and polyphenols with anti-inflammatory activities were highlighted. The discovery of luteolin, in particular, underscores its potential therapeutic role. These findings provide a valuable genomic resource and a scientific basis for the development and application of I. seguinii, addressing the genomic gap in the genus Iodes and the order Icacinales and underscoring the need for further research in genomics, transcriptomics, and metabolomics to fully explore its potential.

Pangeneric genome analyses reveal the evolution and diversity of the orchid genus Dendrobium

Orchids constitute one of the most diverse families of angiosperms, yet their genome evolution and diversity remain unclear. Here we construct and analyse chromosome-scale de novo assembled genomes of 17 representative accessions spanning 12 sections in Dendrobium, one of the largest orchid genera. These accessions represent a broad spectrum of phenotypes, lineages and geographical distributions. We first construct haplotype-resolved genomes for a Dendrobium hybrid and uncover haplotypic variations and allelic imbalance in the heterozygous genome, demonstrating the significance of diverse ancestry. At Dendrobium genus-wide scale, we further elucidate phylogenetic relationships, evolutionary dynamics, entire gene repertoire, and the mechanisms of preserving ancient genetic variants and rapid recent genome evolution for habitat adaption. We also showcase distinctive evolutionary trajectories in MADS-box and PEBP families over 28 Ma. These results considerably contribute to unearthing the mystery of orchid origin, evolution and diversification, laying the foundation for efficient use of genetic diversity in breeding.

A telomere-to-telomere genome assembly of the protandrous hermaphrodite blackhead seabream, Acanthopagrus schlegelii

A remarkable life cycle of the protandrous blackhead seabream (Acanthopagrus schlegelii), initiating as a male during the first two years and then naturally transforming to a female since the third year, makes this fish a valuable model for studying molecular mechanisms of sex change. Here, we constructed a gap-free telomere-to-telomere (T2T) genome assembly for a male blackhead seabream, by integration of PacBio HiFi, Ultra-long ONT and Hi-C sequencing techniques. With 97.87% of the entire sequences anchored into 24 chromosomes, this haplotypic genome assembly spans 714.98 Mb. In terms of correctness (quality value QV: 52.95) and completeness (BUSCO score: 99.9%), this chromosome-scale assembly is indeed of high quality. It has been annotated with 24,581 protein-coding genes, and predicted with low percentage (30.95%) of repetitive sequences. As the first reference T2T-level genome assembly of various protandrous fishes, it provides a valuable genetic resource for expansion of fish genomics database. It will also allow for in-depth genomic comparisons among diverse hermaphrodite vertebrates, as well as offer fundamental genome data to support extensive research on blackhead seabream.