Biology subjects

Chen, M.

Publications and source records attributed to Chen, M..

At least 307 records · Page 17Linked to original sources

bioRxiv2023

CircRNAs and their regulatory networks associated with the antioxidant enzymes and immune responses of Asian honey bee larvae to fungal infection

Non-coding RNA (ncRNA) plays an important role in the regulation of immune responses, growth, and development in plants and animals. Here, the identification, characteristic investigation, and molecular verification of circRNAs in Apis cerana cerana larval guts were conducted, and the expression pattern of larval circRNAs during Ascosphaera apis infection was analyzed. This was followed by exploration of the potential regulatory part of differentially expressed circRNAs (DEcircRNAs) in host immune responses. A total of 3178 circRNAs in the larval guts of A. c. cerana were identified, with a length distribution ranging from 15 nt to 96007 nt. Additionally, 45, 33, and 48 up-regulated circRNAs, as well as 110, 62, and 38 down-regulated circRNAs were identified in the A.-apis-inoculated 4-, 5-, and 6-day-old larval guts in comparison with the corresponding uninoculated larval guts. These DEcircRNAs were predicted to target 29, 25, and 18 parental genes, which were relative to 12, 20, and 17 GO terms as well as 144, 114, and 61 KEGG pathways, including five cellular and four humoral immune pathways containing melanization, phagosomes, lysosomes, endocytosis, apoptosis, MAPK, Ras, and Jak-STAT signaling pathways. Furthermore, complex competing endogenous RNA (ceRNA) regulatory networks were detected as being formed among DEcircRNAs, DEmiRNAs, and DEmRNAs. The target DEmRNAs were engaged in 36, 47, and 47 GO terms as well as 331, 332, and 331 pathways, including six cellular and six humoral immune-related pathways. In total, nineteen DEcircRNAs, five DEmiRNAs, and three mRNAs were included in the sub-networks relative to three antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST). Finally, back-splicing sites within 15 circRNAs and the difference in the 15 DEcircRNAs expression between uninoculated and A.-apis-inoculated larval guts were confirmed utilizing molecular methods. These findings not only enrich our understanding of bee host-fungal pathogen interactions, but also lay a foundation for illuminating the mechanism underlying the DEcircRNA-mediated immune defense of A. c. cerana larvae against A. apis invasion.

molecular biology↗

bioRxiv2023

Structural basis for auto-inhibition and activation of a short prokaryotic Argonaute associated TIR-APAZ defense system

Short prokaryotic Ago accounts for most prokaryotic Argonaute (pAgo) and is involved in defending bacteria against invading nucleic acids. Short prokaryotic Ago associated with APAZ-TIR (SPARTA) has been shown to oligomerize and deplete NAD+ upon guide-mediated target DNA recognition. However, the molecular basis of SPARTA inhibition and activation remains unknown. Here we determine the cryo-EM structures of Crenotalea thermophila SPARTA in its inhibited, transient, as well as activated states. The SPARTA is auto-inhibited by its acidic tail, which occupies the guide-target binding channel. Guide mediated target binding expels this acidic tail and triggers substantial conformational changes to expose Ago-Ago dimerization interface. As a result, SPARTA assembles into an active TIR-APAZ4/short Ago4 octamer, where the four TIR domains are rearranged and packed to form NADase active sites. Together with biochemical evidence, our results provide a panoramic vision explaining SPARTA auto-inhibition and activation, and expand understanding of pAgo mediated bacterial defense systems.

biochemistry↗

bioRxiv2023

A machine learning approach for quantifying age-related histological changes in the mouse kidney.

The ability to quantify aging-related changes in histological samples is important, as it allows for evaluation of interventions intended to effect health span. We used a machine learning architecture that can be trained to detect and quantify these changes in the mouse kidney. Using additional held out data, we show validation of our model, correlation with scores given by pathologists using the Geropathology Research Network aging grading scheme, and its application in providing reproducible and quantifiable age scores for histological samples. Aging quantification also provides the insights into possible changes in image appearance that are independent of specific geropathology-specified lesions. Furthermore, we provide trained classifiers for H&E-stained slides, as well as tutorials on how to use these and how to create additional classifiers for other histological stains and tissues using our architecture.This architecture and combined resources allow for the high throughput quantification of mouse aging studies in general and specifically applicable to kidney tissues.

pathology↗

bioRxiv2023

Single-cell landscape reveals NAMPT mediated macrophage polarization that regulate smooth muscle cell phenotypic switch in pulmonary arterial hypertension

RationalePulmonary arterial hypertension (PAH) is a progressive and lethal disease that leads to elevated pulmonary vascular resistance and right ventricular failure. The phenotypic switching of pulmonary arterial smooth muscle cells (SMCs) plays a crucial role in the pathological progression of PAH. However, the underlying mechanism of SMC phenotypic modulation remains unclear. ObjectivesWe aim to provide a comprehensive understanding of SMC phenotypes and regulatory networks by analyzing hypertensive and non-diseased pulmonary arteries. MethodsWe performed single-cell RNA sequencing (scRNA-seq) on pulmonary arteries obtained from patients with PAH and healthy donors. This was followed by bioinformatics analyses, mouse models, and in vitro studies to construct a normal pulmonary artery atlas, characterize SMC phenotypes, investigate intercellular communication, and explore the molecular mechanisms underlying SMC phenotypic switching. Measurements and Main ResultsOur scRNA-seq analysis identified specific activation of vascular cells, including myofibrocytes, macrophage M2 polarization, endothelial-mesenchymal transition, and chondroid-like SMCs in healthy pulmonary arteries. In PAH pathology, there was an enhanced phenotypic switch of SMCs from contractile to fibroblast-like. Intercellular communication revealed increased M1 macrophage-SMC crosstalk in PAH, which was facilitated by NAMPT. Using a cellular co-culture system, we found that NAMPT-mediated M1 macrophage polarization induced fibroblast-like phenotypic switching in SMCs via the CCR2/CCR5 axis. ConclusionsOur findings provide a comprehensive cell atlas of healthy human pulmonary arteries and demonstrate that NAMPT-driven M1 macrophage polarization plays a critical role in the fibroblast-like phenotypic switching of SMCs through CCR2/CCR5 cellular crosstalk in PAH.

molecular biology↗

bioRxiv2023

T4SEpp: a pipeline integrated with protein language models effectively predicting bacterial type IV secreted effectors

Many pathogenic bacteria use type IV secretion systems(T4SSs) to deliver effectors (T4SEs) into the cytoplasm of eukaryotic cells, causeing diseases. The identification of effectors is a crucial step in understanding the mechanisms of bacterial pathogenicity, but this remains a major challenge. In this study, we used the full-length embedding features generated by six pre-trained protein language models to train classifiers predicting T4SEs, and compared their performance. An integrated model T4SEpp was assembled by a module searching full-length, signal sequence and effector domain homologs of known T4SEs, a machine learning module based on the hand-crafted features extracted from the signal sequences, and the third module containing three best-performing protein language pre-trained models. T4SEpp outperformed the other state-of-the-art (SOTA) software tools, achieving [~]0.95 sensitivity at a high specificity of [~]0.99, based on the assessment of an independent testing dataset. Additionally, we performed a comprehensive search among 8,761 bacterial species, leading to the discovery of 227 species belonging to 3 phyla and 117 genera that possess T4SSs. Furthermore, leveraging the power of T4SEpp, we successfully identified a grand total of 12,622 plausible T4SEs. Overall, T4SEpp provides a better solution to assist in the identification of bacterial T4SEs, and facilitates studies of bacterial pathogenicity. T4SEpp is freely accessible at https://bis.zju.edu.cn/T4SEpp.

bioinformatics↗

bioRxiv2023

Pan-genome and Haplotype Map of Cultivars and Their Wild Ancestors Provides Insights into Adaptive Evolution of Cassava (Manihot esculenta Crantz)

Cassava is the most important starch sources, a tropical model crop. We constructed nearly T2T genomes of cultivar AM560, wild ancestors FLA4047 and W14, pan-genome of 24 representatives and a clarified evolutionary tree with 486 accessions. Comparison of SVs and SNVs between the ancestors and cultivated cassavas revealed predominant expansion, contraction of genes and gene families. Significantly selective sweeping occurred in the cassava genomes in 122 footprints with 1,519 candidate domestication genes. We identified selective mutations in MeCSK and MeFNR3 promoting photoreaction associated with MeNADP-ME of C4 assimilation in modern cassava. Co-evolved retardation of floral primordia and initiation of storage roots arose from MeCOL5 mutants with altered bindings to MeFT1, MeFT2 and MeTFL2. MebHLHs evolved to regulate the biosynthesis, transport and endogenous remobilization of cyanogenic glucosides, with new functionalities of MeMATE1, MeGTR in selected sweet cassava. These findings enhanced comprehensive knowledge and database on the evolution and breeding of cassava. HIGHLIGHTSO_LIThree nearly T2T cassava genomes of cultivar AM560 and its wild ancestors FLA4047 and W14. C_LIO_LIA species-level cassava panSV haplotype map across 346,322 structural variations over 31,362 gene families and 96,032,008 SNPs and InDels variations globally and a clarified evolutionary tree with 486 accessions. C_LIO_LISelective mutations in MeCSK and MeFNR3 promoted photoreaction associated with MeNADP-ME of C4 assimilation shaped the C3-C4 intermediate photosynthesis of modern cassava. C_LIO_LICoevolution of floral primordia contrary to initiated storage root is pivotal for the domestication of cassava, and arose from MeCOL5 mutants altered the binding with MeFT1, MeFT2 (SP6A), and MeTFL2. C_LI

systems biology↗

bioRxiv2023

Applying Artificial Intelligence to Identify Common Targets for Treatment of Asthma, Eczema, and Food Allergy

Allergic disorders are common diseases marked by the abnormal immune response towards foreign antigens that are not pathogens. Often patients with food allergy also suffer from asthma and eczema. Given the similarities of these diseases and a shortage of effective treatments, developing novel therapeutics against common targets of multiple allergies would offer an efficient and cost-effective treatment for patients. Herein, we employed the artificial intelligence-driven target discovery platform, PandaOmics, to identify common targets for treating asthma, eczema, and food allergy. Thirty-two case-control comparisons were generated from 15, 11, and 6 transcriptomics datasets related to asthma (558 cases, 315 controls), eczema (441 cases, 371 controls), and food allergy (208 cases, 106 controls) respectively, and allocated into three meta-analyses for target identification. Top-100 high-confidence targets and Top-100 novel targets were prioritized by PandaOmics for each allergic disease. Six common high-confidence targets (i.e., IL4R, IL5, JAK1, JAK2, JAK3, and NR3C1) across all three allergic diseases have approved drugs for treating asthma and eczema. Based on the targets dysregulated expression profiles and their mechanism of action in allergic diseases, three potential therapeutic targets were proposed. IL5 was selected as a high-confidence target due to its strong involvement in allergies. PTAFR was identified for drug repurposing, while RNF19B was selected as a novel target for therapeutic innovation. Analysis of the dysregulated pathways commonly identified across asthma, eczema, and food allergy revealed the well-characterized disease signature and novel biological processes that may underlie the pathophysiology of allergies. Altogether, our study dissects the shared pathophysiology of allergic disorders and reveals the power of artificial intelligence in the exploration of novel therapeutic targets.

immunology↗

bioRxiv2023

Establishment of a novel non-integrated human pluripotent stem cell-based gastruloid model

Embryo loss and pregnancy disorders are prevalent worldwide, with both conditions critically associated with dysfunctioning gastrulation processes. Gastrulation and post-gastrulation organogenesis are crucial stages of embryonic development that establish the blueprint for body part formation. These processes involve the sequential generation of three germ layer cells and primordial germ cells, as well as the assembly of the precursor tissues for body parts. However, due to ethical limitations associated with studying human embryogenesis, a more detailed understanding of gastrulation and post-gastrulation organogenesis remains elusive. To ensure that the knowledge obtained from gastruloids is biologically meaningful and clinically relevant, it is critical to create high-fidelity human embryo models that closely mimic embryogenesis in vivo. Here, we developed a two-stage derivation gastruloids in vitro based on human pluripotent stem cells. Morphological tracking mimicks the developmental processes of models from Carnegie Stage 4 (CS4) to early CS7. Our gastruloids exhibit key structures characteristic of human embryos, including amniotic cavity, embryonic disc, primitive streak, primary yolk sac, secondary yolk sac, and blood islets. Comparison of our cell lineage development maps showed that gastruloids closely resembled human natural CS7 gastrula. Our gastruloids exhibited transcriptional characteristics that mimicked the molecular pathways observed in natural embryos development. Importantly, we found that in our model, extraembryonic mesoderm originates from the yolk sac and primordial germ cells originate from the posterior epiblast of the embryonic disc. Moreover, we found that thalidomide affects the differentiation of three germ layer cells, resulting in the arrest of human gastruloid development. In conclusion, by establishing a human gastruloid, we were able to gain valuable insights into the mechanisms responsible for human gastrulation and shed light on the causes of early embryo loss and pregnancy disorders.

developmental biology↗

bioRxiv2023

EquiScore: A generic protein-ligand interaction scoring method integrating physical prior knowledge with data augmentation modeling

Developing robust methods for evaluating protein-ligand interactions has been a long-standing problem. Here, we propose a novel approach called EquiScore, which utilizes an equivariant heterogeneous graph neural network to integrate physical prior knowledge and characterize protein-ligand interactions in equivariant geometric space. To improve generalization performance, we constructed a dataset called PDBscreen and designed multiple data augmentation strategies suitable for training scoring methods. We also analyzed potential risks of data leakage in commonly used data-driven modeling processes and proposed a more stringent redundancy removal scheme to alleviate this problem. On two large external test sets, EquiScore outperformed 21 methods across a range of screening performance metrics, and this performance was insensitive to binding pose generation methods. EquiScore also showed good performance on the activity ranking task of a series of structural analogs, indicating its potential to guide lead compound optimization. Finally, we investigated different levels of interpretability of EquiScore, which may provide more insights into structure-based drug design.

bioinformatics↗

bioRxiv2023

Insights from the Early Cretaceous: The promise of Lycoptera aDNA sequencing

Obtaining high-quality ancient DNA (aDNA) is a crucial process for advancements in molecular paleontology. However, current research is restricted to a limited range of fossil types due to DNA degradation and contamination from environmental DNA (eDNA). Utilizing the technology of nanoparticle affinity beads, we successfully extracted DNA from Lycoptera davidi fossils and obtained 1,258,901 DNA sequences. To ascertain their origins, we developed and implemented a novel protocol, the "mega screen method", designed to categorize aDNA fragments. This approach successfully identified 243 Actinopterygii species-specific fragments (SSFs), which subsequent analysis confirmed as original in situ DNA (oriDNA) sequences. Lycoptera davidi, a ray-finned fish from the Early Cretaceous Jehol Biota, dates back approximately 120 million years (Ma). Notably, the absence of deamination in certain oriDNA and paleoenvironmental DNA (paeDNA) fragments calls into question its reliability as a definitive marker for aDNA identification, a phenomenon potentially attributable to the protective effects of fossil diagenesis. Additionally, we identified a novel mechanism, "coding region sliding replication and recombination", responsible for generating new transposase. This mechanism, distinct from conventional processes such as horizontal gene transfer or vertical inheritance from parents, can facilitate a rapid genomic diversification. The transposase CDS insertion into the GAS2 gene of Anabarilius grahami offers molecular insights into the genetic interactions between ancestral carp and Lycoptera and the swift emergence of the expansion of early fish species starting from the early Cretaceous. These findings enhance our understanding of fossil DNA preservation, lay the groundwork for an ancient species DNA database, and introduce innovative tools for exploring evolutionary relationships across geological timescales.

paleontology↗

bioRxiv2023

Systematic single-cell analysis reveals dynamic control of transposable element activity orchestrating the endothelial-to-hematopoietic transition

BackgroundThe endothelial-to-hematopoietic transition (EHT) process during definitive hematopoiesis in vertebrate is highly conserved. Stage-specific expression of transposable elements (TEs) has been detected during zebrafish EHT and may promote hematopoietic stem cell formation by activating inflammatory signaling. However, little is known about how TEs contribute to the EHT process in human and mouse. ResultsWe reconstructed the single-cell EHT trajectories of human and mouse, and resolved the dynamic expression patterns of TEs during EHT. Most TEs presented a transient co-upregulation pattern along the conserved EHT trajectories. Enhanced TE activation was tightly associated with the temporal relaxation of epigenetic silencing systems. TE products can be sensed by multiple pattern recognition receptors, triggering inflammatory signaling to facilitate the emergence of hematopoietic stem cells. Furthermore, we observed that hypoxia-related signals were enriched in cells with higher TE expression. Additionally, we constructed the hematopoietic cis-regulatory network of accessible TEs and identified potential enhancers derived by TEs, which may boost the expression of specific EHT marker genes. ConclusionsOur study provides a systematic vision on how TEs are dynamically controlled to promote the hematopoietic fate decision through transcriptional and cis-regulatory networks, and pre-train the immunity of nascent hematopoietic stem cells.

bioinformatics↗

bioRxiv2023

Decoding Root Biogeography: Building Reduced Complexity Functional Rhizosphere Microbial Consortia

The rhizosphere microbiome plays a crucial role in supporting plant productivity and contributes to ecosystem functioning by regulating nutrient cycling, soil integrity, and carbon storage. However, characterizing their functional attributes and microbial relationships remains challenging due to their complex taxonomic and functional compositions. To enable such studies, the development of reduced complexity microbial consortia derived from the rhizosphere microbiome of the natural ecosystem is highly desirable. Designing and assembling reduced complexity consortia that mimic natural communities with consistent, stable, predictable features are highly sought after but is challenging to deliver. Here we present our systematic controlled design towards successful assembly of several such rhizosphere derived reduced complexity consortia. From Brachypodium grown in natural soil under controlled lab conditions, we enriched the root-associated microbes, utilizing carbon compounds prevalent in Brachypodium root exudates. By transferring the enrichments every 3 or 7 days for 9 generations, we developed both fast and slow-growing microbial communities. 16S rRNA amplicon analysis revealed that both inoculum and carbon substrates significantly influence microbial community composition. For example, 1/10 R2A preferentially enriched Amplicon Sequence Variants (ASVs) from slow growing taxa vital to plant including Acidobacteria and Verrucomicrobia. Network analysis revealed that although fast and slow growing microbial consortia have distinct key taxa, the key hubs (keystone taxa) for both belong to genera with plant growth promoting (PGP) traits. This suggests that PGP bacteria might play a central role in controlling the microbial networks among rhizospheric microbiomes. Based on the stability and richness results from different transfers, most carbon substrates lead to microbial consortia with reduced complexity and high stability after a few transfers. The stability tests of the derived microbial consortia also showed high stability, reproducibility, and revivability of the constructed microbial consortia. Our study represents a significant step towards understanding and harnessing the potential of rhizosphere microbiomes, with implications for sustainable agriculture and environmental management.

microbiology↗

bioRxiv2023

Deep-learning Based Pathological Assessment of Frozen Procurement Kidney Biopsies Predicts Graft Loss and Guides Organ Utilization: A Large-scale Retrospective Study

BackgroundLesion scores on procurement donor biopsies are commonly used to guide organ utilization. However, frozen sections present challenges for histological scoring, leading to inter- and intra-observer variability and inappropriate discard. MethodsWe constructed deep-learning based models to recognize kidney tissue compartments in H&E stained sections from procurement biopsies performed at 583 hospitals nationwide in year 2011-2020. The models were trained and tested respectively on 11473 and 3986 images sliced from 100 slides. We then extracted whole-slide abnormality features from 2431 kidneys, and correlated with pathologists scores and transplant outcomes. Finally, a Kidney Donor Quality Score (KDQS) incorporating digital features and the Kidney Donor Profile Index (KDPI) was derived and used in combination with recipient demographic and peri-transplant characteristics to predict graft loss or assist organ utilization. ResultsOur model accurately identified 96% and 91% of normal/sclerotic glomeruli respectively; 94% of arteries/arterial intimal fibrosis regions; 90% of tubules. Three whole-slide features (Sclerotic Glomeruli%, Arterial Intimal Fibrosis%, and Interstitial Fibrosis%) demonstrated strong correlations with corresponding pathologists scores (n=2431), but had superior associations with post-transplant eGFR (n=2033) and graft loss (n=1560). The combination of KDQS and other factors predicted 1- and 4-year graft loss (discovery: n=520, validation: n=1040). Finally, by matching 398 discarded kidneys due to "biopsy findings" to transplanted population, the matched transplants from discarded KDQS<4 group (110/398, 27.6%) showed similar graft survival rate to unmatched transplanted kidneys (2-, 5-year survival rate: 97%, 86%). KDQS [≥] 7 (37/398, 9.3%) and 1-year survival model score [≥] 0.55 were determined to identify possible discards (PPV=0.92). ConclusionThis deep-learning based approach provides automatic and reliable pathological assessment of procurement kidney biopsies, which could facilitate graft loss risk stratification and organ utilization. Translational StatementThis deep-learning based approach provides rapid but more objective, sensitive and reliable assessment of deceased-donor kidneys before transplantation, and improves the prognostic value of procurement biopsies, thus could potentially reduce inappropriate discard and stratify patients needing monitoring or preventative measures after transplantation. The pipeline can be integrated into various types of scanners and conveniently generates report after slide scanning. Such report can be used in conjunction with pathologists report or independently for centers lacking renal pathologists.

bioinformatics↗

bioRxiv2023

Imputation Efficacy Across Global Human Populations

Genotype imputation is now fundamental for genome-wide association studies but lacks fairness due to the underrepresentation of populations with non-European ancestries. The state-of-the-art imputation reference panel released by the Trans-Omics for Precision Medicine (TOPMed) initiative contains a substantial number of admixed African-ancestry and Hispanic/Latino samples to impute these populations with nearly the same accuracy as European-ancestry cohorts. However, imputation for populations primarily residing outside of North America may still fall short in performance due to persisting underrepresentation. To illustrate this point, we curated genome-wide array data from 23 publications published between 2008 to 2021. In total, we imputed over 43k individuals across 123 populations around the world. We identified a number of populations where imputation accuracy paled in comparison to that of European-ancestry populations. For instance, the mean imputation r-squared (Rsq) for 1-5% alleles in Saudi Arabians (N=1061), Vietnamese (N=1264), Thai (N=2435), and Papua New Guineans (N=776) were 0.79, 0.78, 0.76, and 0.62, respectively. In contrast, the mean Rsq ranged from 0.90 to 0.93 for comparable European populations matched in sample size and SNP content. Outside of Africa and Latin America, Rsq appeared to decrease as genetic distances to European reference increased, as predicted. Further analysis using sequencing data as ground truth suggested that imputation software may over-estimate imputation accuracy for non-European populations than European populations, suggesting further disparity between populations. Using 1496 whole genome sequenced individuals from Taiwan Biobank as a reference, we also assessed a strategy to improve imputation for non-European populations with meta-imputation, which can combine results from TOPMed with smaller population-specific reference panels. We found that meta-imputation in this design did not improve Rsq genome-wide. Taken together, our analysis suggests that with the current size of alternative reference panels, meta-imputation alone cannot improve imputation efficacy for underrepresented cohorts and we must ultimately strive to increase diversity and size to promote equity within genetics research.

genetics↗

bioRxiv2023

The Haplotype-resolved Autotetraploid Genome Assembly Provides Insights into the genomic evolution and fruit divergence in Wax apple (Syzygium samarangense (BI.) Merr.et Perry)

The wax apple (Syzygium samarangense) is an economically important fruit crop with great potential value to human health because it has rich antioxidant substances. Here, we presented one haplotype-resolved autotetraploid genome assembly of the wax apple with size of 1.59 Gb. Comparative genomic analysis revealed three rounds of whole-genome duplication (WGD) events, including two independent WGDs after WGT-{gamma}. Resequencing analysis of 35 accessions partitioned these individuals into two distinct groups, including 28 landraces and seven cultivated species, and several selectively swept genes possibly contributed to fruit growth, including KRP1-like, IAA17-like, GME-like, and FLACCA-like genes. Transcriptome analysis in three different varieties during flower and fruit development identified key genes related to fruit size, sugar content, and male sterility. We found AP2 also affects the fruit size by regulating the sepal development in wax apples. The expression of sugar transport-related genes (SWEETs and SUTs) was high in ZY, likely contributing to a high level of sugar content. Male sterility in Tub was associated with tapetal abnormalities due to the decreased expression of DYT1, TDF1, and AMS, which affects the early tapetum development. The chromosome-scale genome and large-scale transcriptome data presented in this study offer new valuable resources for biological research on S. samarangense, and sheds new light on fruit size control, sugar metabolism, and male sterility regulatory metabolism in wax apple.

genomics↗

bioRxiv2023

Transposon elements shape population divergence of rice blast fungus Magnaporthe oryzae

Dynamic transposition of transposable elements (TEs) in fungal pathogens have significant impact on genome stability, gene expression, and virulence to the host. In Magnaporthe oryzae, genome plasticity resulting from TE insertion is a major driving force leading to the rapid evolution and diversification of this fungus. Despite their importance in M. oryzae population evolution and divergence, our understanding of TEs in this context remains limited. Here we conducted a genome-wide analysis of TE transposition dynamics in the 11 most abundant TE families in M. oryzae populations. Our results show that these TEs have specifically expanded in recently isolated M. oryzae rice populations, with the presence/absence polymorphism of TE insertions highly concordant with population divergence on Geng/Japonica and Xian/Indica rice cultivars. Notably, the genes targeted by clade-specific TEs showed clade-specific expression patterns and are involved in the pathogenic process, suggesting a transcriptional regulation of TEs on targeted genes. Our study provides a comprehensive analysis of TEs in M. oryzae populations and demonstrates a crucial role of recent TE bursts in adaptive evolution and diversification of the M. oryzae rice-infecting lineage. IMPORTANCEM. oryzae is the causal agent of the destructive blast disease, which caused massive loss of yield annually worldwide. The fungus diverged into distinct clades during adaptation toward two rice subspecies, Xian/indica and Geng/japonica. Although the role of TEs in the adaptive evolution was well established, mechanisms underlying how TEs promote the population divergence of M. oryzae remains largely unknown. In this study, we reported that TEs shape the population divergence of M. oryzae by differentially regulating gene expression between Xian/Indica-infecting and Geng/Japonica-infecting populations. Our results revealed a TE insertion mediated gene expression adaption that led to the divergence of M. oryzae population infecting different rice subspecies.

genomics↗

bioRxiv2023

Lipid transfer proteins initiate nuclear phosphoinositide signaling

Phosphoinositide (PIPn) messengers are present in non-membranous regions of nuclei where they are assembled into a phosphatidylinositol (PI) 3-kinase (PI3K)/Akt pathway that is distinct from the cytosolic membrane-localized pathway. In the nuclear pathway, PI kinases/phosphatases bind the p53 tumor suppressor protein (wild-type and mutant) to generate p53-PIPn complexes (p53-PIPn signalosome) that activate Akt by a PI3,4,5P3-dependent mechanism in non-membranous regions of the nucleus. This pathway is dependent on a source of nuclear PIPns that is poorly characterized. Here we report that a subset of PI transfer proteins (PITPs), which transport PI between membranes to enable membrane-localized PIPn synthesis, also interact with p53 in the nucleus upon genotoxic stress. Class I PITPs (PITP/{beta}) specifically supply the PI required for the generation of p53-PIPn complexes and subsequent signaling in the nucleus. Additionally, the PI 4-kinase PI4KII binds to p53 and the PITPs to catalyze the formation of p53-PI4P. p53-PI4P is then sequentially phosphorylated to synthesize p53-PIPn complexes that regulate p53 stability, nuclear Akt activation and genotoxic stress resistance. In this way, PITP/{beta} and PI4KII bind p53 and collaborate to initiate p53-PIPn signaling by mechanisms that require PI transfer by PITP/{beta} and the catalytic activity of PI4KII. Moreover, the identification of these critical upstream regulators of p53-PIPn signaling point to PITP/{beta} and PI4KII as potential therapeutic targets in this pathway for diseases like cancer. In BreifPhosphatidylinositol transfer proteins and a PI 4-kinase initiate nuclear p53-PIPn signaling in membrane-free regions.

cell biology↗

bioRxiv2023

Genetic basis of expression and splicing underlying spike architecture in wheat (Triticum aestivum L.)

IntroductionWheat is one of the most important staple crops worldwide, and an important source of human protein and mineral element intake. Continuously increasing stable production of wheat is critical for global food security under the challenge of population growth and limited resource input. ObjectiveSpike architecture determines the potential grain yield of wheat. However, the mechanisms of transcriptional regulation of spike architecture in wheat remain largely unknown, limiting further genetic improvement of wheat yield. In this study we explored the genetic basis of spike architecture in wheat. MethodsPopulation RNA-seq methods were used to identify the eQTLs and sQTLs associated with spike architecture and applied this to dissection of the genetic basis of gene expression and splicing controlling these complex yield-related traits. ResultsIn total, 4,143 expression quantitative trait loci (eQTLs) and 12,933 splice QTLs (sQTLs) were identified in wheat based on 178 RNA-seq samples, revealing 774 cis-eQTLs and 321 cis-sQTLs for 86 eGenes and 73 sGenes, respectively. Integration of eQTLs and sQTLs with genome-wide association study (GWAS) identified dozens of additional novel candidate genes that may contribute to spike-related traits. Gene network analysis showed that eQTLs and sQTLs were widely involved in the co-expression modules that regulate wheat spike architecture. Notably, the eQTL locus AX-108754757 regulated the expression of 5 eGenes that negatively controled grain number per spike. AX-111592099 regulated both the splicing and expression of TraesCS7B02G442100, encoding an E3 ubiquitin ligase, and playing a central role in regulating spike length. ConclusionThis study provides new insights into the genetic basis of spike architecture. This improved understanding of spike-related traits in wheat will contribute to more rapid genetic improvement.

plant biology↗